Patent Publication Number: US-2007118496-A1

Title: Service-to-device mapping for smart items

Description:
TECHNICAL FIELD  
      This description relates to smart item technologies.  
     BACKGROUND  
      Smart item technologies may include, for example, radio-frequency identification (RFID) systems, embedded systems, sensor motes, and/or sensor networks, and may be used, for example, to provide business software applications with fast access to real-world data. For example, smart item technologies may be used support the detection, reading, or writing of RFID tags, as well as to support communication with, and control of, wireless sensor networks and embedded systems. In many instances, smart items may include devices having local processing power, memory, and/or communication capabilities, that are capable of providing data about the device and its properties, or information about a current state or environment of the smart item devices. Accordingly, some such devices may be used in the execution of service components of back-end or underlying business applications, and, in particular, may do so in a collaborative way, e.g., by forming mobile ad-hoc networks to collect, process, or transmit business data.  
      Examples of smart item devices include an RFID tag, which may be passive or active, and which may be attached to an object and used to provide product or handling information related to the object. Other examples of smart item devices includes various sensors, such as, for example, environmental sensors (e.g., a temperature, humidity, or vibration sensor), which, as just referenced, may be capable of communicating to form one or more sensor networks. These and other types of smart item devices also may include embedded systems, which may refer generally to any system in which a special-purpose processor and/or program is included, and/or in which the system is encapsulated in the device being controlled.  
      Through automatic real-time object tracking, smart item technology may provide businesses with accurate and timely data about business operations, and also may help streamline and automate the business operations. Accordingly, cost reductions and additional business benefits (e.g., increased asset visibility, improved responsiveness, and extended business opportunities) may be obtained.  
     SUMMARY  
      According to one general aspect, a service is determined, the service being associated with service metadata for describing the service. Device metadata associated with each of a plurality of devices is determined, and a selected device is determined from the plurality of devices, based on the service metadata and the device metadata.  
      Implementations may include one or more of the following features. For example, in determining a service, a request for mapping of the service may be received, and/or the service may be determined as one that is currently running on an originating device.  
      In determining a service, a service executable and the service metadata of the service may be determined from a service repository. Further, service requirements for running the service may be determined from the service metadata. In the latter example, determining the service requirements may include determining one or more of a service behavior, an abstract technical constraint, a concrete technical constraint, a translation between the abstract technical constraint and the concrete technical constraint, an input/output constraint, a precondition, an effect, a static hardware requirement, a dynamic hardware requirement, a processing characteristic, a memory characteristic, a power characteristic, an execution platform, or a network characteristic.  
      Determining device metadata may include defining at least one group of the plurality of devices, defining a group leader device of the group, and instructing the group leader device to query the group to obtain the device metadata for each device within the group, and to forward the obtained device metadata for the group. Further, determining device metadata may include querying the plurality of devices to determine device characteristics of each device. In the latter example, querying the plurality of devices may include determining the device characteristics to include one or more of a device description, a device name, a device identifier, a device type, a device vendor, a software description, an operating system description, a service, a hardware description, a processor description, a connection description, a connection speed, a connection type, a memory description, a total memory, a free memory, a device status, or an execution platform.  
      Determining a selected device from the plurality of devices may include matching corresponding elements between the service metadata and the device metadata. Further, determining a selected device from the plurality of devices may include matching service requirements with corresponding device characteristics of each of the plurality of devices, applying a weighted formula associated with the service to the device characteristics to obtain at least one value associated with each device, and selecting the selected device based on the at least one value.  
      Determining a selected device from the plurality of devices may include determining network metadata associated with a network that includes at least some of the devices, the network metadata including one or more of an available bandwidth, a transmission characteristic, a network protocol, or a current network parameter, and determining the selected device based on the network metadata. Further, determining a selected device from the plurality of devices may include determining administrative system constraints provided by a user requesting deployment of the service, and translating the administrative system constraints for deployment on the selected device.  
      Also, the service may be deployed to the selected device by providing the service to a service injector installed on the selected device.  
      According to another general aspect, a system includes a service repository that is operable to store at least one service in association with service metadata describing service requirements of the service, and a service mapper that is operable to determine device metadata associated with each of a plurality of devices and providing device characteristics of the devices, the service mapper being further operable to map the service to a selected device of the plurality of devices for deployment thereon, based on a matching of corresponding elements of the service requirements and the device characteristics.  
      Implementations may include one or more of the following features. For example, a system monitor may be included that is operable to monitor the plurality of devices and/or network metadata associated with a network in which at least some of the plurality of devices are included.  
      The service mapper may include a global service mapper component that is operable to sort local networks of the sensor network according to local network characteristics, a local service mapper component associated with at least one of the local networks and operable to sort groups of the plurality of devices, and a group service mapper component associated with a group leader of at least one of the groups. The service mapper may be operable to determine the device metadata by distributing device queries using the global service mapper component, the local service mapper component, and the group service mapper component. The service mapper may be operable to map the service by matching the service metadata to the selected device using the global service mapper component, the local service mapper component, or the group service mapper component, and the service mapper may be further operable to update one or more of the global service mapper component, the local service mapper component, or the group service mapper component, in response to the distributing.  
      The service mapper may be operable to determine the selected device based on application of a performance metric to an initial result set of the matching, the performance metric including a weighting of the elements based on each element&#39;s relative importance to executing the service. The devices may include one or more of a radio frequency identification (RFID) reader, a smart items device, a device within a sensor network, a sensor mote, or an embedded systems device.  
      The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a block diagram of a system for service-to-device mapping for smart item devices.  
       FIGS. 2A and 2B  are flowcharts illustrating example operations of the system of  FIG. 1 .  
       FIG. 3  is a block diagram illustrating a system using the three-tier architecture of the system of  FIG. 1 .  
       FIGS. 4A and 4B  are tables illustrating a global service mapper table and a local service mapper table, respectively.  
       FIG. 5  is a block diagram of a smart items infrastructure for implementing the systems of  FIGS. 1 and 3 .  
       FIG. 6  is a flowchart illustrating a service-to-device mapping operation.  
       FIG. 7  is a block diagram of a re-mapping implementation of the system of  FIG. 1 .  
       FIG. 8  is a flowchart illustrating a re-mapping operation according to  FIG. 2B .  
       FIG. 9  is a block diagram of an example implementation of the system(s) of FIGS.  1  and/or  7 .  
       FIG. 10  is a screenshot of a server page for interactively specifying a service-to-device mapping request by a human user.  
       FIG. 11  is an example file format for representing service metadata.  
       FIG. 12  is an example service metadata file using the format of  FIG. 11 .  
       FIG. 13  is an example file format for representing device metadata.  
       FIG. 14  is an example device metadata file using the format of  FIG. 13 .  
       FIG. 15  is a screenshot illustrating results of a service-to-device mapping request.  
       FIG. 16  is a screenshot of a server page showing results of a service-to-device mapping request.  
       FIG. 17  is a screenshot illustrating a portion of a re-mapping procedure. 
    
    
     DETAILED DESCRIPTION  
       FIG. 1  is a block diagram of a system  100  for service-to-device mapping for smart item devices. In the example of  FIG. 1 , a local network  102  that includes various smart item devices provides real-world data to one or more business data processing systems  104  in a timely and accurate manner, using a wide area network  106 . For example, the local network  102  may include smart item devices  108 ,  110 ,  112 , and  114 , referred to herein as “smart items” or simply as “devices,” which may include RFID readers (for reading objects having an RFID tag), various embedded systems, and/or various types of sensors and/or sensor motes.  
      In  FIG. 1 , the device  108  is illustrated as including a central processing unit (CPU)  116 , as well as a memory  118 . Thus, the device  108  should be understood to be capable of various levels of computing capabilities, including, for example, processing or transmitting sensed data (in the case where the device  108  includes a sensor). Although not specifically illustrated in  FIG. 1  for the sake of clarity, it should be understood that the devices  110 ,  112 , and  114  also may include the same or different computing capabilities, including, for example, the capability to form and participate in the local network  102 , such as a wireless network and/or a peer-to-peer network.  
      Thus, the local network  102  may be used to collect, process, filter, aggregate, or transmit data that may be useful to the business data processing systems  104 . For example, the business data processing systems  104  may include inventory management systems, supply chain management systems, retail store management systems, warehouse management systems, and any other system(s) that may be used to execute business processes with respect to real-world objects, where such real-world objects may include, for example, products for sale, pallets or other shipment elements, patients, or manufacturing materials/equipment. By tracking and analyzing such real-world objects, the business data processing systems  104  may be used, for example, to determine inventory levels, set pricing levels, evaluate marketing strategies, evaluate manufacturing or production technologies, reduce theft, or maintain safety.  
      By including smart items as the devices  108 ,  110 ,  112 , and  114  of the local network  102 , processing may be performed very early in the data-collection process(es), so that a burden placed on the business data processing applications  104  may be reduced or eliminated. For example, the business data processing applications  104  may be located at a corporate headquarters, and the local network  102  may represent one of many (types of) networks that may be dispersed across a large geographical region connected by the wide area network  106 . As such, for example, the business data processing systems  104  may only require certain sub-sets or characterizations of data collected by the network  102  (and related networks), and may not need or want all collected data.  
      In some implementations, the business data processing systems  104  may include compound or composite applications that are made from re-usable software components or services that are designed to perform some well-defined task(s). Also, in these or other implementations, the business data processing systems  104  may include legacy applications that may not easily communicate with data-collection devices (or with other business data processing systems), and, in such cases, services or service components may be provided as interfaces between the legacy applications and the data collection devices and/or other systems. The system  100  allows these and other applications and services to be deployed directly on the devices  108 ,  110 ,  112 , and  114 , so that, for example, services may be run on the devices (and data may be collected and/or processed) in a timely, efficient, reliable, automated, cost-effective, and scaleable manner. Thus, for example, business processes may be decomposed into individual services and deployed at different devices.  
      The system  100  includes a service mapper  120  that is operable to select the device  108  as a selected device from among the plurality of devices  108 ,  110 ,  112 , and  114  of the network  102 , for deploying a service  122  thereon, as shown. In so doing, the service mapper  120  accesses a service repository  124  that is operable to store a plurality of services that are eligible for execution within the local network  102  and/or other networks (not shown in  FIG. 1 ). The service mapper  120  determines service metadata  126  along with an actual service executable  128 , and compares the service metadata  126  against device metadata  130  associated with each of the plurality of devices  108 ,  110 ,  112 , and  114 . Based at least on the service metadata  126  and the device metadata  130 , the service mapper  120  may select the device  108  as being particularly well-suited for deployment of the service  122  (including the service executable  128 ) thereon.  
      For example, the device metadata  130  may include a description of each device, the description being constructed according to an ontology and/or schema that is known to the service mapper  120  and common to the various devices  108 ,  110 ,  112 , and  
      114. Additionally, or alternatively, the device metadata  130  may be collected in a device-specific format or structure for each of the devices  108 ,  110 ,  112 , and  114 , e.g., by a system monitor  132 , and may thereafter be converted into such a common schema for use by the service mapper  120 . For example, the device metadata may include a description of various technical capabilities of the devices  108 ,  110 ,  112 , and  114 , provided in an extensible Markup Language (XML)-based language, e.g., by using an XML schema, as described in more detail, below. Of course, other formats, languages, and/or structures may be used, as well.  
      More generally, the device metadata  130  may include, for example, a device description, a software description, a hardware description, and a device status. For example, the device description may include a device name, identifier, or type, or may include vendor information including a vendor name or vendor website. The software description may include an operating system description, including version and/or vendor, or may include a description of services running or allowed to run on the device platform. The hardware description may include information about attributes of the CPU  116  (e.g., name or speed), memory  118  (e.g., total and/or free amount of memory), or connection capabilities (e.g., connection speed or connection type) of the device(s). The device status may include more volatile information, including a device location, current CPU usage, or remaining power or memory. Of course, other device aspects or information may be included in the device metadata  130 , as described below and/or as would be apparent. For example, the device metadata  130  may include information about other devices, such as where the device  108  includes an RFID reader, and the device metadata  130  may include a description of types of RFID tags that may be read and/or written to by the RFID reader.  
      The service metadata  126  may somewhat analogously include various service descriptions and/or requirements that relate to whether and how the service(s) may be executed on one or more devices. For example, the service metadata may include a service behavior description, technical constraints of the service, or information regarding input, output, preconditions, or effects (IOPE) of the service. For example, technical constraints may include a required CPU type or speed, an amount of (free) memory that is needed, a type or speed of connection that is required or preferred, an operating system version/name/description, or a type or status of a battery or other device power source(s).  
      Thus, as with the device metadata  130 , distinctions may be made between static and dynamic service requirements, such as hardware requirements. For example, a static value such as a total memory or maximum processing speed may be included, along with dynamic values such as available memory/processing/power and/or a number or type of other services that may be allowed to concurrently run on a device together with the service(s) in question, at an execution time of the service(s).  
      Construction and use of the service metadata  126  may differ depending on whether the service(s) are considered to be a compound service and/or an atomic service. In this regard, an atomic service refers to a discrete service that runs on a single device, while a compound service refers to a higher-level service that includes and combines one or more atomic services. For example, a compound service may be deployed onto the local network  102  that requires a certain number or type of the devices  108 ,  110 ,  112 , or  114 , in order to provide a cumulative or aggregated function(s), and an atomic service may refer to services, such as the service  122 , that are deployed to individual ones of the devices  108 ,  110 ,  112 , or  114 . For example, the devices  108 ,  110 ,  112 , and  114  may include temperature sensors dispersed in a defined area to determine a temperature distribution or gradient in the area, in which case each of the devices  108 ,  110 ,  112 , or  114  may execute a temperature-collection service (e.g., the service  122  on the device  108 ), while one or more of the devices  108 ,  110 ,  112 , or  114 , or some other device, may execute a compound service that aggregates the temperature data from all of the devices  108 ,  110 ,  112  and  114  and determines information about the temperature distribution or gradient. Thus, for example, it should be understood that part of the service metadata  126  for a compound service may include information regarding atomic services that comprise the compound service.  
      Further, for compound services, abstract constraints such as a density for a service (e.g., a deployment of the compound service at every 5 qm 2 ) may be included in the service metadata  126 , and may need to be translated into a concrete requirement for atomic services involved in the compound service. For instance, the abstract density constraint just mentioned may result in a concrete requirement for atomic services of the corresponding compound service, in which the atomic services are deployed on 10% of all available devices.  
      Thus, a translation process may be used to translate an abstract constraint of a compound service into a concrete service requirement for corresponding atomic services, in the specific context of a given system (e.g., the system  100 ). Such a translation process may determine an abstract constraint of the compound service and translate the abstract constraint into a concrete requirement, based on information regarding the system at hand (e.g., the system  100 ). To the extent that the atomic services for the compound service communicate and work together, it may be reasonable to ensure that the concrete value is the same for all of the atomic services. For example, where the compound service is associated with an abstract constraint of being deployed at every 5 qm 2 , then system information may be applied, such as that a size of a field of the system is 100 qm 2 , with every 5 qm 2  containing ten devices, so that forty devices cover the entire field. Then, the abstract constraint of deployment of the compound service at every 5 qm 2  results in a deployment density of 10% for the corresponding atomic services. That is, in this case, four of the forty devices (10%) will run the compound service and/or the corresponding atomic services, with one device having the service(s) deployed thereon in each 5 qm×5 qm field of the entire 100 qm 2  field.  
      More generally, using at least the service metadata  126  and the device metadata  130 , the service mapper  120  may map a given service onto the devices  108 ,  110 ,  112 , or  114  of the local network  102 . Such a mapping is designed not only to value-match various aspects of the service metadata  126  and the device metadata  130 , where necessary (e.g., matching a required memory specified in the service metadata  126  with a device memory specified in the device metadata  130 ), but also to enable and optimize a deployment and execution of the service in question. For example, it may be the case that both the device  108  and the device  110  are nominally or ostensibly capable of running the service  122  (e.g., both devices  108  and  110  may posses some minimum required values of memory, processing capabilities, or power). However, it may be the case that the service  122  is more power-hungry than memory-hungry (or vice-versa), so that the service mapper  120  may map the service  122  to the device  108  if the device  108  is currently able to provide more power relative to the other candidate device  110 , even if the device  110  currently provides more free memory than the device  108 .  
      More formally, a matching set may be expressed as a function that compares device metadata (e.g., device profiles) for a set of devices with service metadata (e.g., technical requirements) for a service to be deployed. Specifically, a set D cap  may be defined as a set of all available individual device profiles “d,” while s tec  may refer to technical requirements of the service in question. Then the matching set may be defined in Eq. (1) as: 
 
match( s   tec   ,D   cap )={ dεD   cap   |s   tex     ⊂ d}   Eq. (1) 
 
 Thus, a device profile d within the set D cap  is accepted as an element of a matching set only if all technical requirements s tec  of the service in question are fulfilled. 
 
      However, as referenced above, simply matching values of the service metadata  126  with the device metadata  130  may not be sufficient to determine which of the matching or candidate device profiles “d” is qualitatively best-suited to perform the function of the service in question. For example, a performance metric may be applied that assigns a numeric weight to one or more attributes of the device metadata, where the numeric weight(s) may be assigned based on a value of the corresponding attributes to the service in question, so that, for example, the numeric weights may be different for different services (e.g., may be service-specific). For example, such a performance metric may be expressed as in Eq. (2): 
 
 Val   d   =w   1 ( CPU _load)+ w   2 (memory)+ w   3 (battery)+ w   4 (connection_speed)  Eq. (2) 
 
 In Eq. (2), the weighted values w 1 , w 2 , w 3 , and w 4  may be selected to equal “1,” and/or may otherwise be normalized or modified to take into account any differences in units. 
 
      Thus, Eq. (2) may be applied to all available devices (or to all devices within the matching set of Eq. (1)), so that values for Val d  for each device may be obtained. Then, the device-specific values for Val d  may be compared to determine a maximum value for all of the devices in question, and an associated device may be selected by the service mapper  120 . In this way, a device providing a highest-available quality for performing the service in question may be selected.  
      Further, the performance metric of the example of Eq. (2) may be extended to cover other device or application-dependent issues. For example, it may be the case that a certain type or brand of device is known to provide some advantage or benefit in executing a service to be deployed, e.g., in terms of reliability. Therefore, for example, all devices of this type or brand may be assigned an appropriate weight and included in the performance metric of Eq. (2), or in a similar performance metric.  
      Once an appropriate service mapping has been performed, a service injector  134  may be used to install and start the mapped service (e.g., the service  122 ) on the device  108 . The service injector  134  further may more generally be used to manage a life cycle of the service(s), e.g., by performing service updates or stopping the service when necessary.  
      Thus, one task of the service injector  134  is transferring concrete service code (e.g., an appropriate one of the service executable(s)  128 ) to the selected device(s). Thus, the service injector  134  receives and installs the kind of code in question. Such an install component as the service injector  134  may be installed on the device-side as either a single standalone software component, or may cooperate with other installation components in order to distribute the service executables  128 . In the latter case, for example, if the service mapper  120  cannot reach all selected devices for a required service installation, then service injectors on multiple ones of the devices may communicate with each other to accomplish the installation. After installing the service executable  128 , the service  122  may be kept in an inactive state until the service injector sends a start-up signal to change the service to an active state. In a similar way, the service injector  134  may be used to organize the updating and stopping of services.  
      Once mapping of the service  122  has occurred, and the service  122  has been installed and started on the device  108 , then execution of the service  122  may continue, as needed. Over time, however, it may be the case that the device  108  ceases to be the optimal device within the local network  102  for running the service  122 . For example, the device  110  may stop running a service of its own, thereby freeing up sufficient memory, processing, or power resources to surpass the device  108  with respect to running the service  122 . As another example, the device  112  may represent a device that enters the local network  102  at a certain point in time after deployment of the service  122  on the device  108 , and that contains superior resources for running the service  122 . For example, the device  108  may be a Personal Digital Assistant (PDA) and the device  112  may be a laptop with superior computing features than the PDA device  108 . As a final example, it may be the case that the device  108  begins to run low on its own resources (e.g., a battery power may reach an almost-discharged state), thereby resulting in a potential vulnerability of the local network  102  as a whole, and in one of the device  110 ,  112 , or  114  being considered superior for running the service  122 .  
      Thus, the service mapper  120  is operable to re-map, remove, and re-deploy the service  122  from an originating device such as the device  108  to another selected device, e.g., the device  110 , during a run-time of the service  122 . In this way, improved device exploitation and improved reliability may be achieved by relocating services from relatively resource-poor devices to more powerful devices. As described in more detail below, determination of available resources at each device may be performed by the system monitor  132 , so that decisions regarding when and whether to initiate re-mapping may be made accordingly.  
      In executing mapping and/or re-mapping, it may be the case that any or all of the business data processing systems  104 , service repository, system monitor, local network  102 , or devices  108 ,  110 ,  112 , and  114  may be dispersed from one another across a relatively large geographical area that is connected by the wide area network  106 , which may include, for example, the Internet or an enterprise-wide proprietary network. Further, a total number of smart item devices reporting to the business data processing systems  104  may be such that it is impractical or undesirable for the service mapper  120  to individually handle all phases of the service mapping processes for all such devices.  
      Therefore, components or tiers of the service mapper  120  may be used that vary in terms of, for example, the semantics or descriptions used for the service metadata  126  and/or the device metadata  130 , or that vary in terms of available computing power, or that vary in terms of geographical location relative to the business data processing systems  104 , the local network  102 , and/or the devices  108 ,  110 ,  112 , or  114 . For example, a global service mapper (GSM) component  120   a  may be used that is common to a plurality of local networks similar to the local network  102 , and that represents a relatively powerful computing device, such as a workstation or powerful personal computer (PC). Meanwhile, a local service mapper (LSM) component  120   b  may be used that is specific to the local network  102  and the devices contained therein, such as the devices  108 ,  110 ,  112 , and  114  (or other devices, not shown). The LSM component  120   b  may represent a somewhat-less powerful component, such as a Stargate server (described in more detail below) or a PDA. Finally, a group leader service mapper (GLSM) component  120   c  may be used within the local network  102  that is associated with a group that is a sub-set of all devices of the local network  102 . The GLSM component  120   c  may thus be implemented by one of the devices of the local network (e.g., the device  108 , as shown, such as a sensor node), which may generally have the least amount of computing resources of the various service mapper components  120   a ,  120   b , and  120   c . One example of an implementation of such a hierarchical architecture is illustrated and discussed below, with respect to  FIG. 3 .  
      It should be understood that the above description is merely intended to provide an example of a hierarchical layering of an architecture for the service mapper  120 , and that greater or fewer layers of such a hierarchy may be used. By implementing such hierarchically-layered architectures, e.g., as described in more detail below, various features and advantages may be obtained. For example, as referenced above, the system  100  may easily be scaled up to include a large number of smart item devices, while still being able to perform mapping and/or re-mapping of services to and among the devices in a timely, efficient, and cost-effective manner.  
      In the example of  FIG. 1 , the GSM component  120   a  builds the hierarchy&#39;s root of the architecture and may serve as a first addressee of a service mapping request. For example, the GSM component  120   a  may serve as an interface to external modules (such as, for example, a service composition module, not shown in  FIG. 1 ) that may be used to initiate the mapping process.  
      The GSM component  120   a , generally speaking, provides information about its associated local networks (e.g., the local network  102 ), where each such local network may be associated with a physical and/or geographical location, such as a warehouse or a retail store. For example, the GSM component  120   a  may be used to sort the local networks according to their devices, provided services, and any further semantic information, including, as just referenced, location.  
      For instance, the GSM component  120   a  may include a GSM metadata table  136  that stores local network device descriptions that include information about existing devices and device capabilities in the given local network. For example, the GSM metadata table  136  may reflect the information that a given warehouse contains 100 sensors, distributed within the warehouse, and 20 PDA&#39;s that are used by the warehouse employees. In addition to the handling of such device information, the GSM metadata table  136  also may store and provide information about services that are provided in the respective local network. To continue the example just mentioned, the GSM metadata table  136  may store information that a service is installed in the warehouse that measures the warehouse temperature (e.g., using smart item devices, such as sensors). Such information about local networks with their devices, provided services, and further semantic aspects are thus available for use in performing the service mapping to one or more of the devices. A specific example of the GSM metadata table  136  is provided and discussed in more detail below with respect to  FIG. 4A .  
      The GSM component  120   a  generally may not need to include descriptions or information about singular devices and their current usage state(s), and instead may simply maintain descriptions of abstract device classes and associated general attributes. Thus, the responsibility of organizing and tracking individual local networks may be left to the LSM component  120   b . The LSM component  120   b  may be located closer to its associated network devices than is the GSM component  120   a , so that multiple LSM components  120   b  provide a distribution of the data being collected and analyzed by all of the various network smart item devices. As with the GSM component  120   a , the LSM component  120   b  may include a LSM metadata table  138  that stores the device information, along with service information associated with each device, quality of service information, and more specific location information for each device. A specific example of the LSM metadata table  138  is provided below with respect to  FIG. 4B .  
      Although it is possible for the LSM component  120   b  to track and provide information regarding individual smart item devices, the example of  FIG. 1  illustrates a case where the LSM component  120   b  divides its underlying network (e.g., the local network  102 ) into clusters or groups that include a set of possibly heterogeneous devices, typically in close physical proximity. For example, the device  108  and/or one or more of the devices  110 ,  112 , and  114 , and other devices, not shown, may be included in one or more groups associated with the local network  102  and the LSM component  120   b.    
      In the example of  FIG. 1 , the device  108  serves as a group leader for such a group, and contains the GLSM component  120   c . Such a grouping may allow improved control of parts of the landscape of the devices  108 ,  110 ,  112 , and  114 . For example, if a service needs to be evenly distributed in a defined area, then such group partitioning may be helpful. For example, a deployment request or order may require that a service should be installed on 10% of all devices of the local network  102 , so that if the groups are dispersed evenly in the local area, the deployment may occur on a group-by-group basis, rather than with respect to all of the devices at once, so that some of the responsibility for distributing the service may be assigned to the various group leaders.  
      Another example of an advantage provided by the GLSM component  120   c  and the associated device grouping just described relates to an ease and efficiency with which the device metadata  130  is collected, e.g., by the system monitor  132  and/or the service mapper  120  (including the GSM component  120   a , the LSM component  120   b , or the GLSM component  120   c ). For example, at the time of a service deployment request, it may be necessary to determine a current state of certain devices throughout a number of local networks. Accordingly, device queries may be distributed by the GSM component  120   a  to the appropriate LSM components  120   b , and then from the appropriate LSM components  120   b  to the appropriate GLSM components  120   c . In this way, it is not necessary to query all the devices within the global system, or all devices within the various local networks, or even all the devices within a given local network. Rather, only devices that are actual or likely candidates for the particular service mapping may be required to provide their associated device metadata.  
      Analogously, monitoring of the queried devices, or of otherwise-specified devices, may occur at the group and/or local network layer(s), rather than at the global level. For example, the system monitor  132  may include a monitor component  132   a  that is installed on the device  108 . In other examples, however, the monitor component  132   a  may additionally or alternatively be stored on the LSM component  120   b . By monitoring devices in this way, the device metadata  130  may be collected in a timely, efficient, and scaleable manner, so that decisions regarding service mapping or re-mapping may likewise be made expeditiously.  
      Although the above description of  FIG. 1  illustrates examples where the service metadata  126  and the device metadata  130  are used, perhaps with a performance metric, to perform mapping of services from the service repository  124  to one or more of the devices  108 ,  110 ,  112 , or  114 , it should be understood that other information may be useful in performing such a mapping. For example, network metadata  140  may include various network parameters, particularly where such parameters are dynamic and not necessarily discernable from information about any single device. One such example of the network metadata  140  may include available bandwidth on the local network  102 . Other examples include a network topology description describing a distance of devices from the LSM component  120   b  (or other location information), mobility characteristics of the network as a whole, and reliability of network connections. Regarding the location example, for instance, a given service may be deployed to replace a currently-deployed service in a specific area within the local network  102 . In this case, groups within the local network  102  may be associated with a group identifier (ID) as an additional network parameter, so that the deployment may proceed at least in part with respect to such group IDs. For example, the new service may need to be mapped within certain time constraints, so that, in this case, such services may be deployed, based on the group IDs and related information, on devices within groups that are closest to the LSM component  120   b.    
      Further, such group IDs may be used in other settings, as well. For example, a group ID may be used in the service metadata  126  as a service requirement that the service in question be deployed on at least one of a specified number or type of group. Similarly, a group ID may be associated as a parameter of a particular device, within the device metadata  130  associated with that device. In this regard, it should be understood that the group ID may be considered either a static or dynamic (volatile) parameter of the device metadata  130 , depending on whether and how often a device is assigned or re-assigned between groups.  
       FIGS. 2A and 2B  are flowcharts illustrating example operations of the system  100  of  FIG. 1 . Specifically,  FIG. 2A  is a flowchart illustrating an example mapping operation of the system  100 . In the example of  FIG. 2A , a request is received for a service deployment ( 202 ). For example, a user may enter a request to deploy a specified service, using a user interface such as the example user interface discussed below with respect to  FIG. 10 . In other examples, the request may be automated, e.g., may be received from an application of the business data processing systems  104  that requires a service to be deployed.  
      Based on the request, the specified service and associated service metadata may be determined ( 204 ). For example, the service mapper  120 , or, more specifically, the GSM component  120   a , may access the service repository  124  in response to the request to determine whether the requested service is available, and to determine the associated service metadata  126  and service executable  128 . In some examples, the same service may be implemented for a plurality of development platforms, e.g., may be implemented for known development platforms that are based on the C programming language or the Java programming language. By providing such a diversity of development platforms, a given service may be deployable to a wider range or type of devices that may be in use. Information about the development platform(s) of the service in question may be included as a type of the service metadata  126 , along with, for example, any of the various service requirements or preferences for operating the service that are provided and discussed above with respect to  FIG. 1 .  
      Current device metadata may then be obtained for a plurality of devices ( 206 ). For example, the service request may specify particular local networks, device groups, devices, or types of devices. In other examples, the service mapper  120  and/or the GSM component  120   a  may automatically select certain devices or types of devices, based on the service request and/or the associated service metadata. To collect the device metadata  130 , the system monitor  132  may initiate one or more queries (perhaps sent from or in conjunction with the service mapper  120  or associated component thereof) that are distributed to the appropriate devices, and may then collect the device metadata  130  in response to the queries. For example, to distribute the queries and collect the device metadata  130  in return, information from the GSM metadata table  136  and/or the LSM metadata table  138  may be used, and groups of devices may be constructed and associated with group IDs, so as to collect the device metadata in a timely and scaleable manner. In other examples, the device metadata  130  may be collected by periodically requesting device information in anticipation of future service requests.  
      A selected device may be determined from the plurality of devices, based at least on the service metadata  126  and the device metadata  130  ( 208 ). For example, the service mapper  120  or one of its components  120   a ,  120   b ,  120   c  may apply a matching operation according to Eq. (1), in order to determine which of the queried devices allow even the possibility of deploying the service. For example, the matching operation may include a determination that an available platform-specific implementation (executable) of the service (e.g., a Java Virtual Machine for Java-based services) is executable on at least a given one of the device(s), or other device characteristics and capabilities may be matched against service requirements of the service to be deployed. Then, a performance metric such as illustrated in Eq. (2) may be used to determine a selected one of the matched devices as one that allows optimized performance of the service being deployed. Of course, as referenced above, other information may be used to perform the determination of the selected device, including the network metadata  140 .  
      Finally in  FIG. 2A , the service is deployed to the selected device ( 210 ). For example, a service injector, such as the service injector  134 , may be used to deploy, install, and/or start the service on the selected device(s). In some implementations, the service injector  134  represents or includes a plurality of service injectors, where each service injector is associated with a specific development platform. In such cases, the availability of a service injector of a specific type may be included in the device metadata  130  and matched against a corresponding requirement of the service metadata  126 .  
      Thus,  FIG. 2A  illustrates a high-level description of a service-to-device mapping process that may occur in the system  100  or related systems, for the purpose of deploying a service onto a selected device or a set of devices. As referenced above, it may be the case that a service has already been mapped and/or deployed to one or more devices, and that, for a number of possible reasons, it may be determined that the running service should be stopped, removed from the device on which it is currently running, and re-mapped and redeployed to a more preferable device.  FIG. 2B  is thus a flowchart illustrating an example of such a re-mapping process that may be performed by the system  100 .  
      In the example of  FIG. 2B , a motivation for re-deploying a deployed service running on an originating device is determined ( 212 ). For example, as referenced above, it may be the case that the service  122  is deployed and running on an originating device such as the device  108 . Then, the system monitor  132  may be involved in determining a motivation for re-mapping the service  122 , such as, for example, a detection of an availability of a more powerful or better-suited device, e.g., the device  110 , on the local network  102 . For example, such a device may be detected as becoming available as the result of a physical movement of the better-suited device  110  into a range of the local network  102 , or as the result of a cessation of some other service on the device  110  (thereby freeing resources of the device  110  and making the device available for running the service  122 ). In another example, the motivation may include the detection of low power or limited memory at the originating device  108 . In yet another example, the motivation may include a directive to the service mapper  120  to re-deploy the service  122  after some pre-determined time period. As a result of one or more of these motivations, re-mapping may occur that helps ensure that the service  122  is running on a well-suited device on the local network  102 .  
      Once a sufficient motivation has been determined, then re-mapping of the deployed service from the originating device to a device selected from a plurality of devices may occur ( 214 ). For example, the mapping process of  FIG. 2A  may be executed, so that, in such a case, the request for service deployment ( 202 ) of  FIG. 2A  corresponds to the determination of motivation to begin the re-mapping process, which may be expressed or determined, for example, by the system monitor  132 . Further, although the process of  FIG. 2B  is referred to as “re-mapping,” it should be understood that the service on the originating device  108  need not necessarily have been originally mapped by the mapping process of  FIG. 2A . For example, it may be the case that the service  122  was originally installed directly and specifically on the device  108 , without benefit of the mapping process of  FIG. 2A . Thus, re-mapping in this sense refers to any removal and re-deployment of the service  122  or similar service from an originating device to a selected device.  
      Further, it should be understood that some techniques for performing the re-mapping may be dependent on, for example, the motivation for the re-mapping. For example, in a case where a specific device moves into the local network  102 , the mapping may occur directly to that device that initiated the re-mapping in the first place, i.e., such a device will be automatically determined to be the selected or receiving device for the service  122 . In other examples, such as where the motivation includes a detection of impending power loss of the originating device  108 , then the full mapping process of  FIG. 2A  may be performed, e.g., a full querying of devices, matching of the resulting device metadata  130  with the service metadata  126 , and determination and application of the appropriate performance metric, all may occur in order to determine the selected device as including one or more devices such as the device  110 .  
      Once the re-mapping has been performed, the deployed service may be re-deployed at the selected device ( 216 ). For example, the deployed service  122  may be re-deployed from the device  108  to the device  110  or other selected device(s), using a service injector on the device  110 . As discussed in more detail below with respect to  FIG. 7 , such a re-deployment may include a maintaining of a state of the service  122  on the originating device  108 , just prior to the re-deployment. In this way, for example, a continuity of service may be maintained even during the re-mapping process.  
      Then, the deployed service may be removed from the originating device ( 218 ). For example, the service injector  134  on the device  108  may stop and remove the service  122  from the originating device  108 . In this example, removal of the deployed service  122  from the originating device  108  is discussed as occurring after the re-deployment of the service  122  to the device  110 . For example, this may occur in the case where the service  122  is providing some safety function or other service that requires continuity of service (e.g., sensors monitoring dangerous chemicals or condition), so that, especially together with the maintenance of state just referenced, there is little or no time where the dangerous condition(s) are not being monitored. In other examples, however, it should be understood that no state of the service  122  need to be maintained, and the service  122  may be removed from the originating device concurrently with, or before, re-deployment to the device  110 .  
       FIG. 3  is a block diagram illustrating a system  300  using the three-tier architecture of the system of  FIG. 1 . That is, the example of  FIG. 3  illustrates a use of the global, local, and device (group) layers discussed above with respect to  FIG. 1 . For instance,  FIG. 3  illustrates an ability of the system  100  to group different networks by provided service(s) and/or included devices. In this way, a wide range of services may be deployed on a wide range of smart item devices to achieve a variety of business goals, and, moreover, device networks may be structured into communities.  
      Specifically, in  FIG. 3 , a global layer includes a facilities safety management community  302  and an asset tracking community  304 . As should be understood from the above description of  FIG. 1 , each of the facilities safety management community  302  and the asset tracking community  304  may be associated with an implementation of the Global Service Mapper (GSM) component  120   a . Then, for example, the facilities safety management community  302  may include services and devices that are used to determine hazardous conditions (e.g., a presence of combustible or explosive materials or combinations of materials), while the asset tracking community  304  may include services and devices that may be used to track products all the way from their origin/manufacture until the products are placed on a shelf for sale. By segregating services and devices in this way, information from the enterprise may be assigned appropriately, and the various mapping and re-mapping procedures described herein may be performed efficiently, since, for example, no effort is wasted trying to map a vibration-detection service that is useful in the facilities safety management community  302  to a device in the asset tracking community  304 , if it is known in advance that such a service is not useful in the latter context.  
      Then, local networks  306  and  308  may be considered to be part of the local layer referenced above with respect to  FIG. 1 , and may be associated with the facilities safety management community  302 , while a local network  310  is at the local layer and associated with the asset tracking community  304 . As already referenced with respect to  FIG. 1 , each of the local networks  306 ,  308 , and  310  may be associated with a plurality of devices, and, specifically, the local network  306  may be associated with devices  312 ,  314 , and  316 , while the local network  308  may be associated with devices  318 ,  320 , and  322 . Then, the various devices may be grouped to form the group layer of  FIG. 1 , where one of the devices is selected or determined to be a group leader for a given group. In  FIG. 3 , the device  312  is a group leader for the group including the devices  312 ,  314 , and  316 , while the device  322  is the group leader for the devices  318 ,  320 , and  322 .  
      Meanwhile, the local network  310  of the asset tracking community  304  is associated with a group  324  and a group  326 , where the group  324  includes devices  328  (as group leader for the group  324 ),  330 ,  332 , and  334 , and where the group  326  includes devices  336  (group leader for the group  326 ),  338 , and  340 . As should be understood from the above description of  FIG. 1 , the local networks  306 ,  308 ,  310  may include implementations of the local service mapper (LSM) component  120   b . Such an LSM component may include a computing device or server (e.g., laptop computer or Stargate server) that possesses sufficient computing resources and that is physically close to its corresponding devices, compared to their corresponding GSM components. Thus, in  FIG. 3 , the groups  324  and  326  illustrate the fact that in some implementations, only certain devices (e.g., the device  330 ), and not necessarily the group leader device, may have direct access to the device or server running the LSM component  120   b . As a result, in such cases, communications between the LSM component and other devices of the groups  324  and  326  may occur via the directly-connected device  330 .  
       FIGS. 4A and 4B  are tables illustrating examples of the GSM metadata table  136  and the LSM metadata table  138 , respectively. In  FIG. 4A , the GSM metadata table  136  includes a column  402  that identifies an associated local network (e.g., identifies an implementation of the LSM  120   b ). For example, in  FIG. 3 , the column  402  may identify that the local network  306  and/or the local network  308  is associated with an implementation of the GSM component  120   a  that is associated with the facilities safety management community  302 , where this community is identified in a column  404 .  
      Then, a column  406  may be used to refer to corresponding device metadata files (e.g., XML files according to a defined XML schema) that describe, for example, a sensor associated with the LSM component  120   b  that is operable to provide certain capabilities. Analogously, a column  408  may be used to refer to corresponding service metadata files, which describe a general nature of the service(s) in question, including, for example, information regarding a temperature and vibration service that is being implemented by the sensor of the column  406 . A column  410  provides a location of the local network, e.g., with respect to a “warehouse A,” as shown. The device metadata  130  and the service metadata  126  may thus be referenced in the GSM metadata table  136  in a general, high-level way, without requiring the GSM metadata table  136  to maintain a current state of all devices of all (or some) local networks. Of course, other information may be included in the GSM metadata table  136 , such as, for example, whether the device is mobile or fixed.  
      The data files of the GSM metadata table  136  may be stored on one or more servers, and may be loaded by a user on demand. In other implementations, data files of the GSM metadata table  136  may be loaded automatically by the GSM component  120   a , or by an administrator (more generally, it should be understood that virtually any action described herein as being performed by a user may be implemented automatically using an appropriate computing resource(s)). As a result, a service mapping request may be routed to an appropriate GSM component at the global layer, and the corresponding GSM metadata table  136  may be used to determine, e.g., which relevant device/services properties or types may be considered for the service mapping request. By using the GSM metadata table  136  and other such tables, a need to consecutively traverse all available local networks and devices may be reduced or eliminated.  
       FIG. 4B  illustrates an example of the LSM metadata table  138 , and includes a column  412  that identifies a group of devices using an associated group identifier, where a column  414  identifies the members of the group identified in the column  412 . For example, the column  414  may specify that the group of the column  412  includes a PDA and a sensor node, with associated (types of) capabilities.  
      A column  416  specifies (types of) services that may run on the group members (devices) of the column  414 . In  FIG. 4B , the column  416  identifies a display service and a temperature service. Thus, a group may be considered not only as a collection of devices, but also as a collection of services that are offered by the group. In such cases, services may be identified even over a large area and for a number of different types of devices.  
      A column  418  specifies quality-of-service (QoS) issues, such as, for example, a current resource usage of the group identified in the group ID column  412 . By specifying an available QoS of a group, a reliability and performance of the group may be known and evaluated. Finally in  FIG. 4B , a column  420  specifies a location of the identified group within the relevant local network, e.g., within “area  1 ” of a “warehouse A” of the local network, as shown. Thus, the location of the group may be, for example, in close proximity to the LSM component  120   b  for that group, so that, for example, communications between the LSM component  120   b  and the group may be timely and reliable.  
      From  FIGS. 3, 4A , and  4 B and the above discussion, it should be clear that the LSM component  120   b  may be responsible for organizing its own local networks, and, in contrast to the GSM component  120   a  and its storage of higher-level descriptions and classifications of types of devices and/or services, may be responsible for storing information that is specific to actual, individual devices and/or services. As described, the LSM component(s)  120   b  may be physically located closer to their respective devices and networks (e.g., may be located in a same warehouse or other building or site as the devices), and may be used to bridge a space between the GSM component(s)  120   a  and the individual devices. By splitting responsibilities in this manner, a favorable distribution of large amounts of data may be obtained.  
      Thus, the LSM component  120   b  may contain a standard interface to its corresponding GSM component  120   a , from which it may receive mapping requests for mapping a service to one or more of the devices of the LSM component  120   b . The LSM component  120   b , as described in more detail below, may include a gateway server  
      Beyond the examples of  FIGS. 4A and 4B , it should be understood that other parameters and metadata may be included in the GSM metadata table  136  and/or the LSM metadata table  138 . For example, additional properties of the group(s) may be included, such as a scale of each group, e.g., in terms of a maximal number of hops between the group leader and a group member, or in terms of a group size that defines a maximum number of group members that may be included.  
      A third layer of the three-tier architecture(s) of  FIGS. 1 and 3  is the group leader layer, at which the GLSM component  120   c  may be deployed. A group leader thus generally represents a dedicated device of a local network that serves as a representative of a corresponding group into which the local network is clustered (as shown in  FIGS. 1 and 3 ). As shown in  FIG. 4B , such group leaders are registered at the LSM component  120   b  (e.g., stored in the LSM metadata table  138 ) and provide an abstraction from a corresponding, underlying device cluster. Group leaders may thus be used to provide information about respective group members, as well as about the services provided by the group members.  
      The semantic information on each layer of the three-tier architecture may be regarded as building blocks of a light-weight semantic overlay that is put on an underlying mobile ad-hoc network. Such a semantic overlay enables the grouping of semantically-related services or devices together, independent of physical locations of the services/devices. For example, at the global (GSM component  120   a ) layer, physically-distributed local networks may be identified that are connected by the same or similar role(s) within the enterprise. Similarly, groups on the local (LSM component  120   b ) level may be identified with respect to information about the constituent devices and functionalities of these groups.  
       FIG. 5  is a block diagram of a smart items infrastructure  500  for implementing the systems of  FIGS. 1 and 3 , respectively. The smart items infrastructure  500  includes five layers: a device layer  502 , a device level service layer  504 , a business process bridging layer  506 , a system connectivity layer  508 , and an enterprise application layer  510 . The layer  502  may be considered to contain various ones of the devices  108 ,  110 ,  112 , and  114  of  FIG. 1 , or similar devices, across a number of groups, local networks and/or physical locations. Meanwhile, the layers  506 ,  508 , and  510  may be considered to be part of, or associated with, the business data processing systems  104  of  FIG. 1 . Thus, the layer  504  may be considered to represent remaining components of the system  100  of  FIG. 1 , e.g., the service mapper  120  and its components  120   a ,  120   b , and  120   c , the system monitor  132  and its component  132   a , and the service repository  124 , as shown in  FIG. 5 .  
      The device layer  502  thus comprises the actual smart item devices, as well as any communications between them. The device layer  502  also is responsible for presentation of any offered hardware services to the next higher layer, the device level service layer  504 . The devices may include, for example, an RFID device  512 , embedded systems  514 , sensor networks  516 , and any other new or emerging technologies  518 , as would be appropriate.  
      For example, for the RFID device(s)  512 , mobile tags may be attached to real-world objects, and are then read (and optionally written to) by RFID readers. In an implementation using active tags, the active tags may also provide additional sensor data (e.g., a current value or a past value). In RFID, communication is typically initiated by the reader, while tags may or may not directly communicate with each other. Such an RFID reader may be configurable to the extent of processing tag data, e.g., may be configured to perform verification of written data, or to avoid reporting a disappearance of a tag if the ostensibly lost tag in fact reappears within a given time window.  
      Techniques for communicating with the embedded systems  514  may vary on the types of devices of the embedded systems. For example, the embedded systems may represent anything from small-scale, one-chip microcomputers, all the way to full-blown PC hardware. Thus, for example, for devices that have the capabilities of a mobile phone or more (e.g., are able to run a Java Virtual Machine™), implementation may be performed in Java™ or based on OSGi (the latter representing a known framework for implementing a component model for remote installation and management of applications and/or application components). As also described above, the sensor networks  516  may include any number of types of sensors that may include integrated processing power and that may be able to execute peer-to-peer communication.  
      The device level service layer  504  manages the deployable services used by the device layer  502 . Thus, the layer  504  includes the service mapper  120  (and service mapper components  120   a ,  120   b , and  120   c ), the system monitor  132  (and the system monitor component  132 ), and the service repository  124 .  
      As referenced above, the service repository  124  may store at least two kinds of services, compound and atomic services. The compound services generally rely on other services to fulfill their tasks, and may have no directly-executable code of their own; rather, the compound services may include an executable service composition description that is stored in a corresponding service description. Thus, compound services may have one service executable, i.e., the service composition description. In contrast, atomic services do not generally use other services, and have their own directly-executable code. Also, as mentioned above, since an atomic service may be deployable on different platforms, an atomic service may have more than one service executable, e.g., may have a service executable for each of the different platforms.  
      The service repository  124  also may store the service metadata  126 , where such service metadata  126  is described in detail, above, and may include a service name, identifier, version, or vendor, or may describe run-time requirements of the service, including, for example, technical deployment requirements (e.g., high bandwidth, or minimum processing power required), semantic requirements (e.g., that a receiving device have a serial connection and/or many device neighbors), and spatial requirements (e.g., that a receiving device be in the basement, or at a south side of a specified building).  
      Finally at the device-level service layer  504 , a device repository  520  may be included. As should be understood from the above description, the device repository  520  may include, for example, information about devices (e.g., the device metadata) in an manner analogous to that in which the service repository  124  maintains information about services (e.g., the service metadata). For example, device metadata may be stored in the device repository  520  after the results of a device querying operation have been determined, or, in another implementation, may be stored by an administrator based on externally-available information about the devices. For example, as already mentioned, the device metadata may include a device name, power capacity, memory capacity, processing capacity, or other information that may be relevant to mapping (and ultimately deploying) a service to an associated device.  
      At run-time, the system monitor  124  monitors a current system state. Whether and how any part of a state of a service is exposed to the system monitor may be set by a developer of the service at design-time. This state-availability information is thereafter available both to a system administrator and to the service mapper  120 . As also described above, the service mapper  120  receives deployment requests and then determines on which device(s) the corresponding service should be deployed, e.g., by matching the service metadata to the device metadata, which may include a current state of the smart item devices and related local network(s). As also described herein, the service mapper  120  also may react to certain events or conditions, including changes in the network state (as recognized by the system monitor  124 ), and may thereafter decide to re-map a service or add or remove instances of services to better fulfill given deployment requests/requirements.  
      The business process bridging layer  506  includes services designed to aggregate data from the devices at the device layer  502 , provided via the device level service layer  504 , and to transform the data from the device layer  502  into business-relevant information. In so doing, an amount of data sent to back-end enterprise application systems may be reduced, and business logic may be executed for different ones of the enterprise application systems.  
      For example, one or more rule processor  522  may be used to parse incoming messages, support basic operational services (e.g., item movement, association, de-association, or device reading/writing) and support information querying. The rule processor  522  processes user-defined business rules that define or reference any other basic operational services that should be executed or consulted. Using such rules and basic operational services provides a flexible framework to adapt the system  500  to different business scenarios.  
      The rule processor  522  may use a data repository  524  for keeping track of all physical objects of interest, e.g., for keeping track of the current state, location, timestamp, or associated business transaction of a given object being tracked, as well as for keeping track of what future actions are expected. Aggregated information from the data repository  524  may be reported on a regular basis, e.g., daily or monthly.  
      One example of an operation of the layers  502 ,  504 , and  506  includes a “goods receiving” scenario. For example, a provider delivering objects to a receiver may send an Advanced Shipment Notification (ASN) containing a list of all objects in the shipment, along with object identifiers such as Electronic Product Codes (EPCs). The ASN may be stored in the data repository  524 . When the shipment arrives and passes the RFID readers at the device layer  502 , e.g., at a receiving dock door, then the EPCs are read by the RFID readers, and sent to the rule processor  522 . The rule processor looks up the ID of the reader from which the message came, determines a location and role of the reader, and then calls the appropriate basic operational service responsible for handling received shipments. This operational service compares the obtained EPCs with the expected EPCs from previous ASNs, and, if a match is found, reports to an enterprise application  532  that the delivery has arrived and is complete. The executed operational service also may then update the data in the data repository  524 . Services described above, as well as services for receiving and sending the involved messages, may be managed by a service manager  526 .  
      Components in the system connectivity layer  508  may be used to connect different application systems and to support system and data integration. For example, messages and data may be routed to the correct backend systems by an information exchange and transformation module  528 , and also may be transformed thereby to enable a semantically-correct integration. On top of message-routing and transformation services, the system connectivity layer  508  also may be used to transport the service executable(s)  128 , using an external service repository  530 , when a given service is deployed from a development environment to the service repository  124  of the device level service layer  504 .  
      The enterprise application layer  532  includes, for example, traditional enterprise IT systems responsible for controlling and managing enterprise business applications. An enterprise application covering a specific business process may not be a single program, but rather may be composed of different services that work together to achieve a desired functionality. Such services may be provided by the same enterprise system, by another enterprise system within the enterprise application layer  532  (possibly located at a site of a business partner), or by systems from lower layers (e.g., by smart item devices at the device layer  502 ).  
      Finally in  FIG. 5 , development tools  534  may refer to tools for creating enterprise application(s)  532  and other applications/services. Using a development environment integrated with the infrastructure  500  may support the implementation of basic services in manners that are similar to known development tools in the enterprise application space. Further, the development tools  534  may allow the creation of the required service metadata  126 , as well as the inclusion of existing services into new applications. Furthermore, the development tools  534  allow a developer to specify where a certain service should run, to configure individual service instances, and to deploy the services in a desired manner. That is, a developer may develop service metadata/executable(s)  536  using the development tools  534 , and may then provide desired ones of the service metadata/executable(s)  536  for storage in the service repository  124 , and/or for mapping/re-mapping by the service mapper  120  at the same or later time.  
       FIG. 6  is a flowchart  600  illustrating a service-to-device mapping operation. In the example of  FIG. 6 , a service (including and/or associated with service metadata and one or more service executables) is initially developed and registered with the service repository  124  ( 602 ). For example, the development tools  534  of  FIG. 5  may be used to design and construct a service executable and associated service metadata, for implementation on a particular platform type.  
      Local networks may then be identified ( 604 ), at a global level of the three-tier architecture described herein. For example, the GSM metadata table  136  of  FIGS. 1 and 4 A may be determined, in which local network (e.g., LSM) information, including community information, device or service information, and locations, and possibly additional or alternative information, may be stored. As described with respect to  FIG. 4A , such global-level information may be determined and represented at a high or abstract level, e.g., without reference to any particular or singular device, but rather with respect to the types of devices, functions, or services that are known to be associated with a given local network(s). As described below, the GSM metadata table  136  thus serves as a starting point for determining whether and how to proceed with a service-to-device mapping.  
      Accordingly, a service mapping request may be received ( 606 ) at the service mapper  120 , e.g., at the GSM component  120   a . For example, an administrator or other user, or another system component, may access the GSM metadata table  136  with the intent of mapping a desired service to an appropriate local network and device, and may thus issue the service mapping request to the GSM component  120   a  by identifying the desired service or type of service. Such a request may take various forms. For example, the administrator or other system component may request mapping of a specific service to one or more explicitly identified devices, or may request deployment of a service on all (available) devices. The administrator or other system component also may request mapping and deployment of a service to some specified number or percentage of devices. Finally, and as described hereafter in the example of  FIG. 6 , the administrator may specify that the service should be specified on the “best” device or devices for a given context, e.g., according to a performance metric as described above with respect to  FIGS. 1 and 2 A.  
      In the case where target devices are given in the service mapping request, the GSM metadata table  136  may be used to detect all local networks with the specified devices. For instance, if a service needs to be deployed on all PDAs of all local networks, then all local networks which contain PDAs will be retrieved. Thus, a search for the local networks may be supported by abstract device classes maintained in the GSM metadata table  136  as additional information about the local networks.  
      In other examples, descriptions of services may be helpful in determining the local networks. For example, using the service metadata  126 , communities with similar services already running may be found and analyzed to detect relevant (types of) devices that are being used. For example, if a new service that is part of facility safety management needs to be deployed, and since local networks are associated with communities, the corresponding facility safety management community  302  may be used to detect potentially relevant local networks/devices.  
      As further input to the GSM component  120   a , the administrator or other system component may specify certain administrative constraints ( 608 ). For example, the administrator or other system component may specify a required deployment density for the service (as described above with respect to  FIG. 1 ), or may specify use of a certain type of device, or may specify a time constraint for accomplishing the mapping and/or deployment. As also described with respect to  FIG. 1 , such abstract administrative constraints may be translated into concrete constraints with respect to a specific network of devices to which the service will be mapped (e.g., a device density of 10% may be translated into a concrete number of devices in an area associated with a specific local network).  
      The service mapping request may then be compared to the relevant local network information ( 610 ). For example, even at the global layer or level of the GSM metadata table  136 , comparisons of the service mapping request with the local network information may significantly narrow the possible outcomes of the service mapping request. For instance, with regard to  FIG. 3 , if the service mapping request is associated with the asset tracking community  304 , then the local networks  306 ,  308  that are associated with the facilities safety management community  302  may be removed from consideration for the service mapping request. Similarly, device or service or location information of columns  406 ,  408 , or  410 , respectively, may reduce a number of local networks to consider for possible service deployment.  
      Thus, a determination may be made as to whether deployment of the service is feasible ( 612 ). If deployment is not feasible, such as where no devices, services, or locations may be matched with either the service mapping request and/or the administrative constraints, if any, then several actions may be taken ( 614 ). For example, the administrator may be notified, or a wait mode may be entered (e.g., in anticipation of the possibility that some device or network condition will change and deployment will then be feasible). Further, a new service may be provided; e.g., a service may be newly-designed, modified, and (re-)registered with the service repository  124 , such that the newly registered services may be more compatible with prevailing local network conditions.  
      If, however, no obstacles to deployment of the specified service are identified, then the service mapping request may be passed to, and received at, the LSM component  120   b  ( 616 ). The LSM component  120   b  may then open a connection to the service repository  124  to obtain specific service metadata associated with the requested (type of) service ( 618 ). For example, the LSM component  120   b  may obtain an XML document having a pre-determined XML schema and specifying the service metadata, e.g., service requirements, from the service repository  124 .  
      Then, a group and associated group leader thereof may be determined or constructed ( 620 ), in association with a group ID that is unique to the group. As described, a group may be described either by its constituent devices and/or its provided functionality.  
      Group generation within a local network may take place by way of a number of mechanisms. For example, a group may be determined or designated based on a number of parameters/requirements, such as, for example, a maximum number of hops between group member(s) and a (potential) group leader, or a maximum number of members of the group.  
      During group creation, a discovery mechanism may be used that allows device discovery while minimizing network traffic, since network traffic and other send/receive actions of devices are at a premium for smart item devices, which tend to have a relatively small amount of computing and power resources. As part of such processes, message sent out on a local network and intended to build a group may contain both functional and non-functional group attributes, along with the unique group-ID. Then, messages in response from potential group members may be evaluated to create the group. Some devices may be excluded from the arising group due, e.g., to restrictions regarding group size or other attributes. Such rejected devices may start another group creation process in the same or similar way, so that the local network is ultimately divided into groups or clusters (e.g., as shown in  FIG. 3 ).  
      Then, a group leader of each group or cluster may be selected, based on one or more of the following criteria, or on other criteria. For example, in deciding between multiple group members to determine a group leader, factors may be considered that include a resource richness of the potential group leaders relative to one another, since, for example, the group leader may be in communication with the LSM component  120   b  and other group members, and may thus require sufficient resources (e.g., battery, CPU, memory, or bandwidth) to enable this communication. As another example, a larger number of devices to which the potential group leader is connected may allow the potential group leader to act more efficiently in aggregating information from, or propagating information to, its associated group members. As another example, frequent or recent uses of a potential group leader may disqualify that device from acting as group leader again until some condition has been met.  
      Once a group leader has been determined, appropriate routing protocols may be selected to ensure that the potential group member devices may communicate with one another in a feasible and efficient manner. For example, even if a group includes heterogeneous devices such as, for example, laptops, PDAs, or smart phones, communication therebetween should be enabled. Examples of routing protocols include position-based routing (based on physical locations of devices), and/or topology-based routing protocol(s) that relies on a direct proximity of devices.  
      Once the group leader(s) is/are determined, the LSM component  120   b  may send a message to the group leader(s) in order to instruct the group leader(s) to collect device metadata, e.g., device profiles, of its (their) associated group(s) ( 622 ). Collection of device metadata may be performed using various query techniques that are able to collect the device metadata without overwhelming a power and/or communications capacity of the associated local network and devices. Moreover, such query techniques may take into account a potential mobility and unreliability of the local network infrastructure, since, e.g., new devices may join or leave the local network during the query process.  
      Types of query to be performed may vary. For example, hoarding queries may be used that focus on completeness of results. For example, such hoarding queries may execute unique queries (referring to devices that are rare and therefore easily identifiable on the local network), or representative queries (e.g., referring to queries in which service deployment is to occur on all devices of an area, such as all devices in a particular building).  
      In contrast to these hoarding queries, selective queries may include different strategies to provide a scalable and adaptive cluster-based device discovery. Such a device discovery may include (1) an identification of proper clusters that contain required devices, (2) assignment of priority (in which a priority assesses a ranking regarding the query forwarding to the group leader, and indicates from which group more relevant results are expected).  
      Regarding the identification of proper clusters that contain required devices, it should be understood that an absolute number of group members may not be as relevant as a relative number of group members which belong to a specific device class. Regarding assignment of priority, a distance from the group to the gateway server running the LSM component  120   b  may be taken into account. In other words, for example, groups closer to the LSM component  120   b  may require fewer hops to transmit data packets to the LSM component  120   b . Furthermore, groups having relatively greater current resource capabilities may be preferable.  
      For representative queries, which generally target all kinds of devices in the network, a different strategy may be used. For example, the following priorities may be pursued consecutively: groups with the most (non-specific) devices, parallelism of querying and/or retrieval of data, group leader with high available bandwidth, groups with the strongest resource capabilities, and groups close to the LSM component  120   b  in terms of hops.  
      In such representative query techniques, the absolute number of devices which a group contains may be relevant. In these cases, since a representative overview is required, no distinction between specific device types may be required. Parallelism and high availability of bandwidth may be used to enable a fast transfer of a potentially large amount of device profiles, and may be used to organize efficiently the distribution of queries in a mobile and potentially unreliable network.  
      Similar techniques and considerations may be possible for selective queries that target more the performance than the completeness of expected results. For example, strategies regarding “top N” (e.g., ten best nodes on the local networks) and “first N” (e.g., the first devices encountered on the local network and located within a certain distance of the LSM component  120   b ) rely on an appropriate pre-selection of identified device profiles.  
      In general, both these examples of selective queries (“top N” and “first N”) may follow a procedure in which group leaders request device profiles from all their group members, and then the group leaders pre-select received results (i.e., either the best ‘N’ device profiles or the first ‘N’ device profiles). Finally, the group leaders forward the result set to the LSM component  120   b , which may then select the best ‘N’ results overall.  
      It should be understood that in some implementations, a current device landscape will not be permanently monitored. Instead, the necessary information about a current state of the local networks and their devices may be drawn at a time of a service mapping request.  
      Once each group leader has queried its respective group devices using one or more of the query techniques just described, or using other techniques, the group leader may merge the collected device metadata (e.g., device profiles) for forwarding to the associated LSM component ( 624 ). For example, the group leader may create an XML file containing all of the device metadata for its associated devices.  
      In this way, the LSM component has the information necessary to match the known service metadata with the received device metadata ( 626 ). For example, the LSM component  120   b  may have gained the service metadata  126  from the service repository  124 , and, having received the device metadata  130  for a plurality of devices as just described, may match, e.g., service requirements of the service metadata  126  against device profiles of the device metadata  130 . For example, if the service requirements and device profiles are provided in respective XML documents according to a pre-determined XML schema, then parameters and values for, e.g., memory, power, and processing power may be matched against one another to determine some sub-set of devices of at least one group that is capable of handling deployment for the service in question.  
      If an attempt at such a matching operation results in a determination that no deployment is feasible ( 628 ), then one or more of the various options mentioned above ( 614 ) may be invoked, including notification of the administrator, entering a wait mode, registering a new service that is deployable on at least one device, and/or providing new devices or device capabilities.  
      However, if deployment is feasible ( 628 ), and at least a minimum number of matching devices are determined for deployment, then a performance metric may be applied to determine which of the matched devices is/are best-suited to implement the functionality of the service in question. For instance, as in the example above, the service metadata  126  may include information regarding a relative weight or importance of certain ones of the service requirements relative to other ones of the service requirements. Then, these relative weights may be incorporated into the performance metric for comparison against the device metadata, so that the matched devices may be ranked and/or filtered according to which devices are best-suited to perform the service functionality. Then, such best-suited devices may be identified and selected by the LSM component  120   b  for deployment thereon of the service in question.  
      Thus, injection of the service at the selected device(s) may be implemented ( 632 ). For example, as described with respect to  FIG. 1 , the service injector  134  may be used to install and start the service on the selected device. As also mentioned above, the service injector  134  may be selected based on a compatibility with a development platform with the service executable of the service.  
      Once the above-described service-to-device mapping has occurred, the GSM and LSM tables may be updated ( 634 ). For example, information obtained by the LSM component  120   b  and/or the group leader(s) may be reflected in the GSM metadata table  136  and/or the LSM metadata table  138 . For instance, the quality-of-service column  418  of the LSM metadata table  138  may be updated to reflect the new resource usage of each different group. As another example, the group ID column  412  of the LSM metadata table  138  may be updated to reflect the new and/or different groups that exist after the device discovery procedures described above.  
       FIG. 7  is a block diagram of a re-mapping implementation of the system  100  of  FIG. 1 . That is, as already described with respect to  FIG. 2B , the system  100  may be involved in a re-mapping procedure that allows improved device exploitation by relocating services from resource-poor devices to more powerful devices.  
      In  FIG. 7 , devices  110  and  108  are illustrated as the originating device and the selected device, respectively, of the re-mapping procedure of  FIG. 2B . Various elements of devices  108  and  110  are not shown in  FIG. 7  for clarity and brevity, including, e.g., the various elements discussed with respect to the device  108  in the context of  FIG. 1 .  
      The originating device  110  includes a memory  702  that stores a service  704 , a service  706 , and a service  708 . Similarly, the selected device  108  includes the memory  118 , which includes available storage  710  along with a service  712  and a service  714 .  
      The system monitor  132  may include, as shown in the example of  FIG. 7 , system monitor components  132   a  and  132   b , which are operable to detect information about a current resource availability and/or usage of their respective devices for reporting to the service mapper  120 . Of course, in other example implementations, the system monitor  132  may be implemented remotely from the devices  108 ,  110 , and the service mapper  120  may be implemented to include the GSM component  120   a , the LSM component  120   b , and the GLSM component  120   c.    
      Thus, in  FIG. 7 , the monitor components  132   a  and  132   b  may detect and provide resource usage and/or availability information regarding the devices  108  and  110 , respectively. Based on this monitored information, the service mapper  120  may determine that a motivation exists for re-mapping the service  706 . Examples of motivations are provided above, and include a determination of relatively or dangerously low resource levels of the originating device  110 , or an entry of a more powerful or resource-rich device within a range of the local network.  
      As described in more detail below,  FIG. 7  provides an example in which the service  706  is to be re-mapped from the originating device  110  to the selected device  108 . In general, before or during such a re-mapping procedure, a mobility degree of the service  706  (or other service) may be checked by the service mapper  120 , using the associated service metadata of the service  706 . For example, the service metadata may contain information about a location of the originating device  10  (which may limit mobility of the service  706 , e.g., if the originating device  10  is in a location with poor connectivity). As another example, the service metadata may contain information about any dependencies that may exist between the service  706  and the originating device  10  that may prevent the service  706  from being re-mapped.  
      More generally, the mobility degree of the service  706  may be expressed as “fixed,” in which re-mapping is not permitted; “movable,” in which case the service (and possibly a status of the service) may be moved from device to another; and “partly movable,” in which case the service  706  may include different interacting parts, and some of the parts, but not all, are allowed by to be re-mapped.  
      It should be apparent that re-mapping of the service  706  from the originating device  110  to the selected device  108  may, in some implementations, share many features of the mapping process described above, e.g., with respect to  FIG. 6 . Accordingly, re-mapping features that are additional to, or modified from, the mapping process of  FIG. 6  are described in more detail, below.  
      For example, as discussed with respect to  FIG. 2B , it may be necessary or advantageous to save a current state of the running service  706  with respect to the originating device  110 , and, in  FIG. 7 , a data file  716  stored in the memory  702  may be used for this purpose. In this context, the terms state or service state may include, for example, all relevant data that may be associated with the service  706 , and/or that may allow a continuity of execution of the service  706  before, during, and after the re-mapping process.  
      Determination of which data should be moved/included with the service  706  may depend, for example, on the type of service. For example, for an aggregation service like “average temperature,” it may be reasonable to save and to transfer the last calculated temperature value to the selected device  108 . In other implementations, however, it also may be reasonable to transfer the whole temperature history of the average temperature service. Information regarding which service/data may be moved may be included in the corresponding service metadata.  
      The data file  716  may generally be used to save relevant data that is to be moved to the selected device  108 . The data file  716  also may be continuously filled with data during execution of the service  706  on the device  110 , thereby to enable a possible reconstruction of the history or other service data. In either case, it should be understood that any kind of relevant data may be stored in the data file  716  at the time of service re-mapping.  
      Further, the re-mapping procedure, as executed by the service mapper  120 , may be in charge of checking service and/or device data for consistency, and saving them in the data file  716 . In this case, a buffer may be used to facilitate service data storage and transfer. It is also possible to permit different procedures for different services, e.g., to define in the service metadata of a service that the state of the service may be part of a possible relocation.  
      In some implementations, the service  706  (e.g., service executable) may be moved directly from the originating device  10  to the selected device  108 . In other implementations, the service  706  may be identified by the service mapper  120  within the memory  702  of the originating device  110 , but may then be accessed from the service repository  124  for injection onto the memory  118  of the selected device  108 .  
      In some instances, re-mapping may occur between different device types. For example, the originating device  10  may include a PDA, while the selected device  108  may include a laptop computer. Such flexibility may benefit from a selection of proper service executables, which should be able to interpret the service metadata found in the data file  716 . An interpretation of service metadata in this sense may include support information for supporting the corresponding data types, and may include different opportunities of data presentation. For example, a laptop usually has a bigger display size, with a higher resolution, than that of a PDA display. The data transferred from the PDA may be shown by a more sophisticated presentation format, e.g., via a data graph. Additionally, the data storage format and/or technique may be specific to a particular device type, e.g., one device may use a file format/system while another uses a binary format/system.  
      Thus, in some implementations, service re-mapping is only allowed between devices of the same pre-determined classes or types. In other implementations, a translation service (not shown) may be used that translates the given service metadata into an appropriate data format which is supported by the selected device  108 . For example, such a translation service may use the service metadata of the chosen service executable to identify which data transformations are required.  
       FIG. 8  is a flowchart  800  illustrating a re-mapping operation according to  FIG. 2B . In  FIG. 8 , a motivation is determined for re-mapping of a deployed service running on an originating device ( 802 ). For example, as already referenced above, it may be the case that a device is on the verge of running out (or moving below a minimum-required level) of some resource, such as memory or power. In some implementations, and with reference to  FIG. 7 , determining a motivation may include detecting the motivation (e.g., low levels of memory or power) at the monitor component  132   b  running on the originating device  110 , which may then send an alert or notification to the service mapper  120  if device resources run short.  
      Or, a new or changed device landscape may enable or force such a re-mapping, in order to provide better resource utilization for the network as a whole. A new device landscape may include one or more new powerful devices which lend themselves as new service providers. Services running on relatively less-powerful devices may then be transferred to these more capable devices, in order to achieve a better load-balancing within the network.  
      Another example of a motivation for re-mapping includes a directive to conduct re-mapping in specified intervals as part of a global monitoring, which may be initiated, for example, by the GSM component  120   a  and/or the LSM component  120   b . Such a global monitoring may determine the motivation in these cases based on whether other defined system constraints are violated. For instance, it may be preferable that certain device groups obey certain invariants, such as, for example, a battery threshold beneath which the group members should not fall, and these invariants may be used as a system constraint. For example, there may exist some groups within the local network  102  that represent more crucial functionality (i.e., more important services) than other groups, so that, in order to ensure a stable environment for such groups, a possible invariant for such crucial groups may be defined, such as the battery threshold just mentioned.  
      Further, different quality of service (QoS) attributes may be defined for one or more groups, and these QoS attributes may be observed in regular intervals. In these implementations, violation of certain QoS attributes may serve as a motivation for re-mapping. In the context of mobile wireless networks, QoS may refer either to service-level attributes or resource-level attributes. At the service level, reliability and performance may be mentioned, whereas at the resource level, factors such as CPU load, memory, bandwidth, and battery levels represent typical attributes. Generally, then, reliability or performance of a running service may be strongly dependent on current resource capabilities. For example, a lower battery status may increase a probability of device failure in the near future, and may therefore correspond with a reduction in an expected reliability of an associated service.  
      Once proper motivation has been determined, service metadata associated with the service to be re-mapped is determined ( 804 ), and a determination of current device metadata also may be made for each of a plurality of devices ( 806 ). For example, the service metadata  126  may be determined from the service repository  124 , while the device metadata  130  may be determined using the various device discovery, group leader formation, and/or profile-querying and/or forwarding techniques described above in the context of the various service-to-device mapping examples provided above.  
      Of course, such techniques may be modified as needed. For example, in a case where the service  706  is only allowed to be re-mapped within the local network  102 , there may be no need to perform an inspection of other local networks (e.g., using the GSM metadata table  136 ). In another example, it may be the case that the motivation for re-mapping includes the entry of a new device to the local network  102 , in which case device metadata need only be collected for the new device. Thus, for example, the LSM component  120   b  may receive aggregated device profile(s) of one or more devices, from a group leader of the associated local network.  
      Further, re-mapping predicates, if any, may be applied ( 808 ). Re-mapping predicates refer generally to technical requirements of a service that are required to be fulfilled before re-mapping may occur. Such re-mapping predicates may include, for example, requirements of an initial mapping of the service to the originating device, group invariants such as those mentioned above, or location constraints. For example, if the initial mapping did not require the selection of the best devices according to a performance metric, then the re-mapping process of  FIG. 8  may attempt to apply such a performance metric. As another example, location constraints may be used when failure to re-map the service within an initial group results in the service being moved to a device of a closest neighbor group.  
      Then, the selected device may be determined, based on the service metadata and the device metadata ( 810 ). For example, a matching operation may be performed between similarly-tagged items within XML files of the service metadata and the device metadata. Also, a performance metric may be applied after the matching operation concludes, in order to select a device from the matching devices that is best-suited for implementing the service, according to the performance metric.  
      As already described, it should be understood that in some cases an identity of the selected device may ostensibly already be known, e.g., based on the determination of the motivation for re-mapping in the first place, such as when a new powerful device enters the local network and triggers re-mapping. In such cases, determination of the selected device may still be considered to refer to application of a matching operation and/or performance metric to the device metadata of the newly-available device, since the determination of the motivation for a possible re-mapping may not be sufficient to ensure an actual viability or desirability of the re-mapping. For example, a device may enter the network with large available reserves of memory and/or power, but may have some other incompatibility (e.g., only operates on a particular development platform) that may prevent re-mapping.  
      A current service state existing on the originating device may be determined and stored ( 812 ). For example, in  FIG. 7 , the current service state of the service  706  may be stored in the data file  716 . The service state may include, for example, most-recently collected data, or most-recently calculated data analysis, or a recently-updated service history.  
      Then, any re-mapping rules may be determined and applied ( 814 ). In this context, re-mapping rules refer generally to rules that prevent otherwise allowed re-mappings, in order to maintain system stability, performance, and/or reliability. For example, one such rule may limit a number or frequency of re-mappings that may be performed with respect to a particular device or pair of devices. For instance, in a case where the device  108  provides sufficient memory space for re-mapping of the service  706 , it may occur that the following re-mapping process will free up sufficient memory on the device  110  to trigger a determination of motivation to re-map the service  706  back to the device  110 . In other words, the very act of re-mapping may trigger a subsequent re-mapping, which may thus lead to a loop of alternating re-mappings.  
      Therefore, a first example of a re-mapping rule may be based on an ordering of device metadata (e.g., device profiles). For example, a weighted metric similar to Eq. (2) may be used to assign a numeric value to each device profile, i.e., based on weighted resource attributes. Then, to solve the problem of a frequent alternating re-mapping process, a re-mapping rule may be created in which re-mapping is realized if and only if a difference between calculated values of an originating and a selected device is larger than some defined threshold. Thus, depending on a value of this threshold, remapping will only be undertaken in cases where one or more devices with significantly superior resource abilities than the originating device are available.  
      In a second example of a re-mapping rule, a frequency of involvement of each device in re-mapping process(es) may be determined. Then, to avoid alternating re-mappings, an originating device may only become a target or selected device again if a certain defined time has elapsed. Thus, every device may possess a local timer that indicates the last time when the device was involved in a re-mapping process. In other implementations, one or more global timers may be implemented by the LSM component  120   b  that applies to one or more devices of one or more groups of the local network. Such a timer may typically be reset after each re-mapping.  
      Of course, other re-mapping rules may be defined and implemented. Additionally, various combinations of these re-mapping rules may be used, including a combination of the two examples rules just described.  
      If the re-mapping rules are satisfied, then the service may be re-deployed to the selected device ( 816 ). For example, the LSM component  120   b  may transfer the service executable from the service repository  124  to the selected device, e.g., using an appropriate service injector, as already described.  
      The LSM component  120   b  also may initiate the transfer of the service state, e.g., using the data file  716 , and initiate the service on the selected device, e.g., again, using the appropriate service injector ( 818 ). Finally in  FIG. 8 , the LSM component  120   b  may send a stop command for the service on the originating device ( 820 ). In some implementations, the actual stopping of the service on the source device may be accomplished after the transfer is finished. For example, as referenced above, services that are employed to detect or to avoid dangerous situations may be required to be continued until the re-mapped and re-deployed service is ready to take over control from its new position on the selected device.  
       FIGS. 9-19  provide various examples of the service-to-device mapping and/or re-mapping techniques described above.  FIG. 9  is a block diagram of a class diagram of an OSGi implementation of the three-tier service mapper  120 , including the GSM component  120   a , the LSM component  120   b , and the device  108  (running the GLSM component  120   c  of  FIG. 1 ).  
      In the example of  FIG. 9 , examples of appropriate devices for each of the illustrated components are discussed in more detail below, and OSGi bundles are installed on each of the devices and managed by the OSGi environment. The bundles may thus communicate with one another to implement the service-to-device mapping (and/or re-mapping) described herein.  
      More specifically, the GSM component  120   a  may be implemented in the example of  FIG. 9  by a laptop computer running an installed GSM bundle  902 . The GSM bundle  902  is in charge of starting the service mapping and deployment by calling a Java Server Page (JSP), which is an example of a known technique for generating dynamic web pages on a web server, that displays the GSM metadata table  136  (as described in more detail below, with respect to  FIGS. 10 and 17 ). Of course, as referenced above, this implementation is merely an example, and, in other implementations, the service mapping may be initiated by a call from another system component, e.g., using an application program interface (API) associated with the GSM component  120   a . The GSM bundle  902  also may be used to update the GSM metadata table  136  based on results of the service-to-device mapping.  
      The LSM component  120   b  in  FIG. 9  may be a gateway server that may have lesser computational resources than the GSM component  120   a . The LSM component serves as a gateway having an installed LSM bundle  904  that receives a service mapping request from the GSM component  120   a  and then conducts the service-to-device mapping. Specifically, the LSM bundle may forward the service-to-device mapping request, collect device profiles of devices within (groups of) the local network, and match the device profiles or other device metadata against service metadata (e.g., requirements). The LSM bundle  904  thus also may notify the group leader(s) of group(s) of the devices that profiles are needed, notify the GSM component  120   a  of results of the matching operations, and update the LSM metadata table  138 .  
      The device  108  in  FIG. 9  includes a PDA running an installed group leader bundle  906 . The group leader bundle  906  is operable to query/search profiles or other device metadata of group devices, merge the profiles into a single message, and send the message with the profiles to the LSM component  120   b . The group leader bundle  906  also may update group information, e.g., for inclusion in the LSM metadata table  138 .  
      Finally in  FIG. 9 , the device  110  is illustrated as a group member that receives a request for its profile from the group leader  108 , and responds to that request with the appropriate profile. Of course, the device  110  also may ultimately receive the service being mapped or re-mapped, and results of such mapping or re-mapping may be reported to the group leader device  108 , as well.  
       FIG. 10  is a screenshot  1000  illustrating an example of the GSM table prior to a beginning of a service-to-device mapping. In the example of  FIG. 10 , and as mentioned above, the screenshot  1000  may represent a JSP page, on which an administrator or other user may first explore the types of devices and already-installed services may exist in the identified local networks. For example, the GSM metadata table  136  is illustrated as containing information about both the facility safety management community  302  of  FIG. 3 , as well as the asset tracking community  304 .  
      Thus, for example, the administrator may select services and/or devices of the GSM metadata table  136 , e.g., using a drop-down list  1002  for selecting available devices, and/or a drop-down list  1004  for selecting available services. Such selective lists may show all available devices that exist in an enterprise (within the different local networks), as well as all services inserted in the service repository  124 . The administrator may thus select various types of service-to-device mapping. For example, the administrator may start the service mapping/deployment on all devices of a device type (e.g., PDA) chosen by way of the list  1002 , or may deploy a chosen service on the best-available device of a specific device type.  
      In the first example, the service mapper  120  may, in response to a selection of a “check and deploy” button  1006 , investigate whether the technical requirements of a selected service may be fulfilled by the current device capabilities. In the second example, the service mapper may detect the most powerful device with respect to available resources, based on a selection of a “check best device and deploy” button  1008  by the administrator. Finally in  FIG. 10 , a reset button  1010  allows the administrator to reset the fields of the JSP of the screenshot  1000 , while a “notification about deployment” field  1012  provides post-deployment (and/or attempted deployment) information to the administrator (an example of which is shown in  FIG. 16 ). As should be apparent, the described identification of local networks, devices, and/or services may either be performed manually by an administrator, or as part of an automatic process.  
      Once the administrator has started the service-to-device mapping by selecting the button  1006  or  1008 , input parameters such as service name, device type, and deployment mode (e.g., some, all, or best device(s)) are transferred to the LSM component  120   b . Then, the LSM bundle  904  receives these input parameters, and opens a connection to the service repository  124  to retrieve the corresponding service metadata (e.g., a service description file) that may contain information regarding technical requirements of that service.  
       FIG. 11  is an example of such a service metadata file  1100 . Specifically,  FIG. 11  illustrates an XML file (“service.xml”) in which a section  1102  identifies the nature of the file as a service metadata (e.g., service requirements) description file, while a section  1104  in the remainder of the file includes various requirements for service parameters including memory, CPU, battery, platform, and connection characteristics, as shown.  FIG. 12  is an example of a specific instance  1200  of the service metadata file of  FIG. 11 , in which specific parameters are illustrated for the various service requirements. Thus,  FIG. 12  may be understood to be a specific example of an instance of the service metadata  126  of  FIG. 1 . Specifically, for example, section  1402  specifies a memory requirement of 300 MB, a CPU speed of 200 MHz, and corresponding measures for other illustrated parameters related to battery life, platform information, and connection characteristics. Although the illustrated descriptions files are shown as XML files, it should be understood that other file-types and/or representation formats may be used.  
      After the gateway server/LSM component  120   b  receives and saves the service description file (e.g., the file illustrated in  FIG. 12 ), the various service-to-device mapping operations described above (e.g.,  FIG. 2A  and  FIG. 6 ) may be implemented. For example, a message may be sent to the group leader device  108 , which may collect all device metadata (e.g., device profiles) of its group member devices, and merge the profiles into a single XML-file (profiles.xml). This XML-file will be send back to the gateway server/LSM component  120   b .  FIG. 13  is a partial example of such an XML-file  1300 , in which a first section  1302  identifies the nature of the file as a device metadata (e.g., device profile) description file, while a section  1204  in the remainder of the file includes various requirements for service parameters including a device description (e.g., name, type, or vendor) and a hardware description (e.g., CPU description, connection characteristics, and memory description). As just mentioned,  FIG. 13  is a partial example, and it should be understood from the discussion above that various other device characteristics may be included in the device profile. For example,  FIG. 14  illustrates a specific instance  1400  of a full example of the device profile of  FIG. 13 , and includes a description portion  1402 , a hardware description portion  1404 , a software description portion  1406 , and a device status portion  1408 . As illustrated, each of these portions  1402 - 1408  may include various device parameters that correspond to the examples provided above with respect to  FIG. 1 , or may include other device parameters. Thus,  FIG. 14  may be understood to be a specific example of an instance of the device metadata  130  of  FIG. 1 .  
      The gateway server/LSM component  120   b , after receiving the device metadata XML-file with all current device capabilities, may perform matching of the device metadata file with the service metadata file. For example, the gateway server/LSM component  120   b  may parse both XML-files, i.e., the service.xml file of  FIG. 13  and the profiles.xml file of  FIG. 15 . Then, gateway server/LSM component  120   b  may compare the technical requirements of the service with the current device resources. For example, the value of the tag &lt;memory&gt;, contained in service.xml will be compared with the corresponding tag &lt;memory&gt;, contained in profiles.xml-file.  
      Finally, the gateway server/LSM component  120   b  informs the laptop/GSM component  120   a  about the devices on which the requested service may be deployed. If no such device is available, the gateway server/LSM component  120   b  may inform the laptop/GSM component  120   a  that no available device fulfills the technical requirements of the service, and may provide a specific reason as to why the service could not be deployed on that specific device, e.g. not enough available memory.  
      For example, with regard to  FIG. 10 , it may be the case that the administrator wishes to deploy the temperature service showing a current temperature of goods in a warehouse on a PDA. In this example, there may be five PDAs within the warehouse. The administrator may access the JSP of the screenshot  1000  of  FIG. 10 , and select the device(s) and service using the lists  1002  and  1004 , respectively. Then, the administrator may select the “check and deploy” button  1006 .  
      As a result, the gateway server/LSM component  120   b  may perform as already described, with results of such performance being provided in a log window  1500  of  FIG. 15 . Specifically, a section  1502  illustrates that the gateway server/LSM component  120   b  accesses the service repository  124  to obtain the service metadata (e.g., requirements) file, such as is illustrated in  FIG. 12 . In a section  1504 , the gateway server/LSM component  120   b  sends a message to the group leader device  108  with instructions to obtain device metadata (e.g., device profiles) for each device within the group, such as is illustrated in  FIG. 14 , which is then saved.  
      Then, in a section  1506 , a matching operation is performed, in which, in this example, memory requirements of the service are matched against device characteristics. As shown, four of the five checked device profiles have sufficient memory, while a fifth device (PDA) does not. Therefore, in  FIG. 16 , a screenshot  1600  of an updated version of the JSP of the screenshot  1000  is illustrated in which the “notification about deployment” field  1012  informs the administrator of the fact that the service was installed on four of the five devices, but that the fifth device did not have sufficient memory.  
      Of course, the above provides just one example, and many other examples are possible. For instance, the administrator may prefer to deploy the service only on the best PDA of the five PDAs available. In this case, the administrator may simply select the “check best device and deploy” button  1008 , and, in the present example, the service mapper  120  will identify and deploy the service to the PDA having the most memory capacity.  
       FIG. 17  is a screenshot  1700  for performing a re-mapping operation. Specifically,  FIG. 17  illustrates an example in which a JSP is used that includes a field  1702  for identifying a re-mapping rule that governs the re-mapping process. Further, a field  1704  is used to identify a device type, while a field  1706  is used to identify a device property, and a field  1708  is used to identify a threshold for the parameter(s) of the rule. A field  1710  provides space for comments explaining an implementation of the rule. In this case, the rule specifies that re-mapping is to be conducted if the memory of a PDA in the network/group reaches the specified parameter threshold of 30 MB. In other words, for example, the rule specifies that a system monitor component may determine whether and when one or more PDAs of the five available PDAs are capable of providing at least 30 MB of memory for (re-)deployment thereon of a designated service. In the screenshot  1700 , a save button  1712  allows the administrator to save the displayed rule, while a reset button  1714  allows the administrator to reset the contents of the fields  1702 - 1710  of the screenshot  1700 . Finally, a “show rules” button  1706  allows the administrator to view one or more of any rules that have previously been created. Also, as already mentioned, one or more of the various functions described above with respect to  FIG. 17  may be performed by a system component, using an API of the GSM component  120   a , rather than by a human user.  
      During re-mapping, and as already described with respect to  FIGS. 2B and 8 , the re-mapping process may be supported by the gateway server/LSM component  120   b . For example, to enable remapping, the LSM bundle  904  may start a control thread designed to observe whether the administrator has defined any re-mapping rules. If a new rule is set by the administrator, the thread will receive and save it. If a service re-mapping needs to be performed, the gateway server/LSM component  120   b  may relocate the service from a relatively resource-poor device to a relatively resource-rich device (e.g., the most resource-rich device presently available).  
      When the group leader device  108  receives the request from the gateway server/LSM component  120   b , the group leader device  108  begins collecting all device profiles of its associated group. Since, in this example, the group contains four other group members, the group leader device  108  may send a message to the group members, whereupon each one of the group members may respond with its corresponding device metadata (e.g., its device profile).  
      As already described, the group leader device  108  may then receive the incoming device profiles and merge them into a single xml-file (e.g., according to the profiles.xml message format of  FIG. 13 ). Once all profiles are received and merged, the group leader device  108  may send the collected device profiles to the gateway server/LSM component  120   b.    
      Additionally, or alternatively, the PDA bundle  906  may start a control thread which observes the device landscape. Accordingly, if a new device joins the network, the group leader device  108  may be informed by this thread. For example, such a new device may be required to send a “hello-message” to the device landscape thread. If the group leader device  108  recognizes such a new group member, then a collection process for collecting the device profiles (inclusive of the new profile) may start. The group leader device  108  may then send the merged profiles to the gateway server/LSM component  120   b  (as described above), so that the gateway server/LSM component  120   b  may then determine whether and how re-mapping should be conducted.  
      Upon receiving the merged device profiles, the gateway server/LSM component  120   b  may perform the matching operations described herein, and possibly implement an appropriate performance metric. Then, and assuming that at least one of the devices matches the parameter threshold(s) and therefore satisfied the re-mapping rule(s), then the pertinent service may be re-mapped and redeployed as described herein.  
      As described herein, an architectural framework and a service-to-device mapping algorithm enable the automatic intelligent mapping of services to appropriate smart item devices. The mapping mechanism is based on a sophisticated description of the semantics of services (e.g., technical requirements like memory or CPU power, expected input/output, behavior and possibly other properties) and available devices (e.g., technical capabilities in terms of memory, CPU and battery life, as well as reliability). Based on this knowledge, and for a given service to be deployed, the service mapper identifies possible candidate devices that could host the service. Then, based on the technical requirements and properties of the service and the devices, respectively, the most cost-effective device (for example, in terms of processing and memory capabilities) is selected for automatic deployment.  
      Implementations of the various techniques described herein may be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in combinations of them. Implementations may implemented as a computer program product, i.e., a computer program tangibly embodied in an information carrier, e.g., in a machine-readable storage device or in a propagated signal, for execution by, or to control the operation of, data processing apparatus, e.g., a programmable processor, a computer, or multiple computers. A computer program, such as the computer program(s) described above, can be written in any form of programming language, including compiled or interpreted languages, and can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program can be deployed to be executed on one computer or on multiple computers at one site or distributed across multiple sites and interconnected by a communication network.  
      Method steps may be performed by one or more programmable processors executing a computer program to perform functions by operating on input data and generating output. Method steps also may be performed by, and an apparatus may be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application-specific integrated circuit).  
      Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. Elements of a computer may include at least one processor for executing instructions and one or more memory devices for storing instructions and data. Generally, a computer also may include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto-optical disks, or optical disks. Information carriers suitable for embodying computer program instructions and data include all forms of non-volatile memory, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and the memory may be supplemented by, or incorporated in special purpose logic circuitry.  
      To provide for interaction with a user, implementations may be implemented on a computer having a display device, e.g., a cathode ray tube (CRT) or liquid crystal display (LCD) monitor, for displaying information to the user and a keyboard and a pointing device, e.g., a mouse or a trackball, by which the user can provide input to the computer. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback, e.g., visual feedback, auditory feedback, or tactile feedback; and input from the user can be received in any form, including acoustic, speech, or tactile input.  
      Implementations may be implemented in a computing system that includes a back-end component, e.g., as a data server, or that includes a middleware component, e.g., an application server, or that includes a front-end component, e.g., a client computer having a graphical user interface or a Web browser through which a user can interact with an implementation, or any combination of such back-end, middleware, or front-end components. Components may be interconnected by any form or medium of digital data communication, e.g., a communication network. Examples of communication networks include a local area network (LAN) and a wide area network (WAN), e.g., the Internet.  
      While certain features of the described implementations have been illustrated as described herein, many modifications, substitutions, changes and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the embodiments of the invention.