Abstract:
A method and system for monitoring a mobile ad-hoc network node (e.g. a network enabled aircraft) is provided. The method includes, receiving a message notifying when the ad-hoc node is preparing to join the ad-hoc network; and determining based on a threshold value, when the ad-hoc node should be joining a monitoring system that tracks the status and availability of ad-hoc nodes. The method generates a status message if the ad-hoc node fails to join the monitoring system. The message is received by the monitoring system via and external source to the ad-hoc network. The system includes a data center that receives the message notifying when the node is preparing to join the ad-hoc network; and determines based on a threshold value, when the ad-hoc node should be joining the ad-hoc network and monitoring system.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims priority under 35 U.S.C. § 119(e) (1) to the following provisional patent application, the disclosure of which is incorporated herein by reference in its entirety Ser. No. 60/563,358, filing date Apr. 19, 2004. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     This invention relates generally to network monitoring, and more particularly, to a method and system to manage ad-hoc network nodes.  
         [0004]     2. Description of Related Art  
         [0005]     Computer networks exist and operate in various forms. Networks include local area networks, wide area networks, wireless networks, the Internet and others. An ad-hoc network, as used herein throughout the specification is a network that is constantly changing. An ad-hoc network node is an entity that is capable of joining or leaving the ad-hoc network at any given time.  
         [0006]     Various entities exist that may fall within the ad-hoc network node concept described above. For example, aircrafts, ships, boats, trains, buses and even automobiles can be classified as ad-hoc network nodes if they are monitored using a network. With today&#39;s changing global society it is important to efficiently and reliably monitor these ad-hoc network nodes. The term node and ad-hoc network node; and network and ad-hoc network are used interchangeably throughout this specification.  
         [0007]     Conventional monitoring systems fail to effectively monitor ad-hoc network nodes. For example, in the case of aircrafts, currently, ACARS (Aircraft Communications Addressing and Reporting System) a standard message format incorporated herein by reference in its entirety, SITA Flight Briefing Service and other similar systems report data on aircraft flight operations by sending and receiving radio frequency or facsimile messages from a ground station. ACARS and SITA collect information on an aircraft and send messages from the aircraft to a ground station where the messages are sent to a computer.  
         [0008]     Although useful, the data reported by ACARS and the other available systems is delayed and sometimes interrupted or not available for a number of reasons, such as the aircraft being out of range, or weather conditions, etc.  
         [0009]     Real-time aircraft location/position data (may also be referred to as navigation data), for example, longitude and latitude of an airborne aircraft may be collected via satellites. An airplane communicates with one or more satellite and data is sent to a satellite gateway. The gateway in turn provides navigation data to one or more ground stations. Real-time information and ACARS messages are often un-correlated and hence under utilized.  
         [0010]     Therefore, there is a need for a method and system that can receive plural data inputs and efficiently monitor ad-hoc network node (for example, aircraft) status.  
       SUMMARY OF THE INVENTION  
       [0011]     In one aspect of the present invention, a method for monitoring a mobile ad-hoc network node using an ad-hoc network is provided. The method includes, receiving a message notifying when a network node is preparing to join the ad-hoc network; determining based on a threshold value, when the ad-hoc network node should be active; and receiving a message notifying when the ad-hoc network node will no longer be part of the ad-hoc network. The message is received by a monitoring system via a source external to the ad-hoc network. The method also includes, generating a status message if the ad-hoc network node fails to join the monitoring system.  
         [0012]     In yet another aspect, a computer-readable medium storing computer-executable process steps of a process for use in a computer system for monitoring a mobile ad-hoc network node using an ad-hoc network. The medium includes, code for receiving a message notifying when a mobile ad-hoc node is preparing to join the ad-hoc network; and code for determining based on a threshold value, when the mobile ad-hoc node should be joining the ad-hoc network. The computer readable medium also includes code for generating a status message if the mobile ad-hoc node fails to join the ad-hoc network.  
         [0013]     In yet another aspect of the present invention, an apparatus for monitoring a mobile ad-hoc network node is provided. The apparatus includes, a storage device for storing computer executable process steps; and a processor for executing computer executable process steps for receiving a message notifying when a mobile ad-hoc node is preparing to join the ad-hoc network; and determining based on a threshold value, when the mobile ad-hoc node should be joining the ad-hoc network.  
         [0014]     In yet another aspect, the present invention includes, a system for monitoring a mobile ad-hoc node using an ad-hoc network is provided. The system includes, a data center that receives a message notifying when the mobile ad-hoc node is preparing to join the ad-hoc network; and determines based on a threshold value, when the mobile ad-hoc node should be joining the data center. The message is received via a source external to the ad-hoc network.  
         [0015]     In one aspect, the present invention provides a monitoring system that utilizes automated data external to an ad-hoc network (e.g. the Internet or any other network) to receive data from and send messages to an ad-hoc network node (e.g. an aircraft).  
         [0016]     In yet another aspect, an operations data system is connected to a data-center that continuously monitors the status of an ad-hoc network node (e.g. an aircraft) aircraft in real-time, either directly or in conjunction with any existing reporting system. The present invention allows a control center, or any other entity to efficiently monitor ad-hoc nodes.  
         [0017]     In one aspect, the present invention provides flight operations data system that receives information from existing aircraft reporting systems, and may utilize this information to predict the status of an aircraft.  
         [0018]     This brief summary has been provided so that the nature of the invention may be understood quickly. A more complete understanding of the invention can be obtained by reference to the following detailed description of the preferred embodiments thereof, in connection with the attached drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]     The objects and features of the present invention, which are believed to be novel, are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation, together with further objects and advantages, may best be understood by reference to the following description, taken in connection with the accompanying drawings, wherein:  
         [0020]      FIGS. 1A-1C  show block diagrams of flight monitoring systems, used according to one aspect of the present invention;  
         [0021]      FIG. 1A   1  shows a block diagram of a monitoring system for monitoring ad-hoc network nodes, according to one aspect of the present invention;  
         [0022]      FIG. 1D  shows examples of ACARS messages;  
         [0023]      FIGS. 1E-1F  show block diagrams of system components, used according to one aspect of the present invention;  
         [0024]      FIG. 1G  shows a block diagram of a computing system for executing process steps, according to one aspect of the present invention;  
         [0025]      FIG. 1H  shows the internal architecture of the computing system in  FIG. 1G ;  
         [0026]      FIGS. 2-5  show process flow diagrams of computer-executables steps, according to one aspect of the present invention;  
         [0027]      FIG. 6  shows an example of a screen with a status message, according to one aspect of the present invention; and  
         [0028]      FIG. 7  shows a process flow diagram for monitoring an ad-hoc network node, according to one aspect of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0029]     The following description is provided to enable any person skilled in the art to make and use the invention and sets forth the best modes contemplated by the inventors of carrying out their invention. Various modifications, however, will remain readily apparent to those skilled in the art, since the generic principles of the present invention have been defined herein, specifically to provide for a method and system for monitoring the status of ad-hoc nodes in real-time and sending messages to the ad-hoc node and/or an operations center using the ad-hoc network (for example, the Internet).  
         [0030]     In one aspect of the present invention, a method and system is provided whereby an aircraft having an on-board installation for high-speed Internet access may be continuously monitored from a ground station and receive messages via the Internet from the ground station. The system may work alone or in conjunction with other aircraft reporting systems fed from airline control centers to monitor the status of aircraft from loading to unloading and to send messages via the Internet to the aircraft and or airline control centers via email or other systems.  
         [0031]     It is noteworthy that although the examples provided below to illustrate the adaptive aspects of the present invention are based on monitoring aircraft flight status, the same method and system can be used to monitor other ad-hoc nodes, for example, ships, trains, buses and/or automobiles.  
         [0032]     To facilitate an understanding of the preferred embodiments of the invention, the general architecture and operation of a system for collecting an aircraft&#39;s flight operations data will be described. The specific architecture and operation of the preferred embodiments will then be described with reference to the general architecture.  
         [0033]     Data Collection System:  
         [0034]      FIG. 1A   1  shows a top-level block diagram for monitoring the status of an ad-hoc network node  102 B. Ad-hoc network node  102 B can leave or join the network (e.g. the Internet) at any time. Node  102 B is operationally coupled to a data collection center  103 A that transmits node  102 B data to a data center  105 A. As discussed above, node  102 B may be an aircraft, boat, train and/or automobile. Data center  105 A includes an enterprise class operation center (“EOC”)  106  and network operation center (“NOC”)  105  that receive node  102 B data via Internet  101  and/or data collection center  103 A. A block diagram for monitoring an aircraft (i.e. node  102 B) will now be described with respect to  FIGS. 1A-1E .  
         [0035]      FIG. 1A  shows a top-level block diagram for collecting real-time navigation data from an aircraft that functions as ad-hoc network node. An aircraft data center  102  located on aircraft  102 A communicates with a satellite  103  and with the Internet  101  (the ad-hoc network). As shown in  FIG. 1A , plural aircrafts operate as ad-hoc network nodes. Data center  102  has the capability to connect to the Internet  101  via an Internet provider.  
         [0036]     It is noteworthy that the ad-hoc network in this example is Internet  101 , however, the adaptive aspects of the present invention may be implemented using any type of network, for example, SITA or ARINC, a private network or any other automated system that can send and receive messages from an ad-hoc node. Also since data center  105 A is operationally coupled to the Internet  101 , it can also be classified as an ad-hoc network.  
         [0037]     Satellite  103  collects aircraft  102 A flight data and navigation data, which is then passed to satellite gateway  104 , that is functionally, coupled to Internet  101  (described below) and/or a data center  105 A.  
         [0038]     As discussed above, data center  105 A includes a network operation center (“NOC”)  105  and an enterprise operation center (“EOC”)  106 . Both NOC  105  and EOC  106  include at least a computing system for executing the computer-executable code, according to one aspect of the present invention. A description of a computing system used by NOC  105  and/or EOC  106  is provided below.  
         [0039]     NOC  105  monitors a computing network by receiving input from plural sources, for example, ACARS messages, and real-time aircraft status information. NOC  105  processes the various inputs, according to the adaptive aspects of the present invention.  
         [0040]     It is noteworthy that the invention is not limited to data center  105 A architecture. NOC  105  and EOC  106  may be an integral part of data center  105 A to execute the process steps of the present invention. The modular components shown in various figures and described herein are intended to illustrate the adaptive aspects of the present invention and not to limit the present invention to any particular configuration.  
         [0041]      FIG. 1B  shows another block diagram of the data collection system described above with respect to  FIG. 1A .  FIG. 1B  shows plural ground stations  104 A- 104 D that collect data from an aircraft while it is in transit. Ground stations  104 A- 104 D are similar to satellite gateway  104 . Ground station position data  107  includes the locations of plural ground stations  104 A- 104 D and sent to data center  105 A. Data collected from the ground stations is processed by data center  105 A, according to the adaptive aspects of the present invention.  
         [0042]      FIG. 1C  shows a block diagram for collecting ACARS messages that are used by data center  105 A. Aircraft  102 A via data center  102  provides status information to an airline operations center  107 . ACARS message  108  is then sent to data center  105 A via Internet  101 .  
         [0043]     In one aspect, ACARS message  108  may be sent using electronic mail or file transfer protocol (“FTP”). It is noteworthy that the adaptive aspects of the present invention are not limited to any particular protocol or system for transferring ACARS messages. ACARS messages  108  may be stored in database  105 B and is accessible to both NOC  105  and EOC  106  for processing, as described below.  
         [0044]      FIG. 1D  shows a block diagram with various stages for ACARS messages  108 . In general, an ACARS message may include, the flight status (i.e., Pre-flight, Flight Out, Flight Off, Flight On and Flight In), pre-flight time, an Airline unique identifier, flight number, aircraft registration number, scheduled departure airport, scheduled time of departure, actual departure time from the gate, time the aircraft takes off, scheduled arrival airport, passenger count, actual arrival airport, actual landing time and arrival time at the gate.  
         [0045]     ACARS pre-flight message (INT)  108 A includes basic flight information, for example, departure city, schedules departure time, scheduled arrival time, and scheduled arrival city.  
         [0046]     Message (ACARS (OUT)  108 B includes, actual departure time and passenger loading. Message  108 C (ACARS(OFF) provides the time when the aircraft takes off and the time it is in the air.  
         [0047]     Message  108 D (ACARS (ONN) provides the time when the aircraft lands and message  108 E (ACARS (INN) provides the actual arrival time at the gate, actual arrival airport and arrival city.  
         [0048]      FIG. 1E  shows yet another block diagram of a data collection system that receives data  108 ,  109  and  110  from plural sources and is processed according to one aspect of the present invention, as described below. As discussed above with respect to  FIG. 1C , ACARS messages  108  are received by data center  105 A via Internet  101 .  
         [0049]     Ground station  104  provides real-time data, described above with respect to  FIG. 1A . This data is collected by using Aircraft Inertial Reference Unit (‘IRU”) standard interface, incorporated herein by reference in its entirety. Data  104 A may be received by EOC  106  and includes, real-time latitude and longitude positions of the aircraft, ground speed, tack angle, true heading, pitch angle, roll angle, body pitch angle, body role rate, body yaw rate, inertial altitude and inertial vertical speed.  
         [0050]     Data  109  is received from aircraft data center  102  and includes an IATA airline identifier, flight number, aircraft&#39;s unique tail number, the actual departure airport, arrival airport, distance to destination, destination-estimated time of arrival and the time to destination.  
         [0051]     Data  110  may be from any other source, for example, a government entity during an emergency and is received by data center  105 A via the Internet  101 . Data  110  may be delayed or real-time.  
         [0052]      FIG. 1F  shows a top-level block diagram of a system that executes the adaptive process steps, according to one aspect of the present invention. System  105 F includes a receiving module  105 C that receives data from an ad-hoc node  102 B (for example,  104 A,  108 ,  109 , and/or  110 ) and forwards data to processing module  105 D for processing the data, according to the various adaptive aspects of the present invention. Output module  105 E outputs the processed information to a designated source in one or more formats. It is noteworthy that system  105 F may be located in NOC  105  and/or EOC  106 , or any other computing system that can be connected to the Internet  101 .  
         [0053]     Computing System:  
         [0054]      FIG. 1G  is a block diagram of a computing system for executing computer executable process steps according to one aspect of the present invention.  FIG. 1G  includes a host computer  10  and a monitor  11 . Monitor  11  may be a CRT type, a LCD type, or any other type of color or monochrome display (or any other display device including a high definition television station).  
         [0055]     Also provided with computer  10  are a keyboard  13  for entering data and user commands, and a pointing device  14  for processing objects displayed on monitor  11 .  
         [0056]     Computer  10  includes a computer-readable memory storage device  15  for storing readable data. Besides other programs, storage device  15  can store application programs including web browsers by which computer  10  connect to the Internet  101 , and the computer-executable code according to the present invention.  
         [0057]     According to one aspect of the present invention, computer  10  can also access computer-readable floppy disks storing data files, application program files, and computer executable process steps embodying the present invention or the like via a floppy disk drive  16 . A CD-ROM, or CD R/W (read/write) interface (not shown) may also be provided with computer  10  to access application program files, and data files stored on a CD-ROM.  
         [0058]     A modem, an integrated services digital network (ISDN) connection, or the like also provide computer  10  with an Internet connection  12  to the World Wide Web (WWW). The Internet connection  12  allows computer  10  to download data files, application program files and computer-executable process steps embodying the present invention from Internet  101 .  
         [0059]     It is noteworthy that the present invention is not limited to the  FIG. 1G  architecture. For example, notebook or laptop computers, handheld devices, set-top boxes or any other system capable of running computer-executable process steps, as described below, may be used to implement the various aspects of the present invention.  
         [0060]      FIG. 1H  is a block diagram showing the internal functional architecture of computer  10 . As shown in  FIG. 1H , computer  10  includes a central processing unit (“CPU”)  20  for executing computer-executable process steps and interfaces with a computer bus  21 . Also shown in  FIG. 1H  are a video interface  22 , a WWW interface  23 , a display device interface  24 , a keyboard interface  25 , a pointing device interface  26 , and storage device  15 .  
         [0061]     As described above, storage device  15  stores operating system program files, application program files, web browsers, and other files. Some of these files are stored using an installation program. For example, CPU  20  executes computer-executable process steps of an installation program so that CPU  20  can properly execute the application program.  
         [0062]     Random access memory (“RAM”)  27  also interfaces to computer bus  21  to provide CPU  20  with access to memory storage. When executing stored computer-executable process steps from storage device  15  (or other storage media such as floppy disk  16  or WWW connection  12 ), CPU  20  stores and executes the process steps out of RAM  27 .  
         [0063]     Read only memory (“ROM”)  28  is provided to store invariant instruction sequences such as start-up instruction sequences or basic input/output operating system (BIOS) sequences for operation of keyboard  13 .  
         [0064]     Computer-executable process steps, according to one aspect of the present invention may be performed using the Internet  101 . The following provides a brief description of the Internet.  
         [0065]     Internet  101 :  
         [0066]     The Internet connects plural computers world wide through well-known protocols, for example, Transmission Control Protocol (TCP)/Internet Protocol (IP), into a vast network. Information on the Internet is stored world wide as computer files, mostly written in the Hypertext Mark Up Language (“HTML”). Other mark up languages, e.g., Extensible Markup Language (XML) as published by W3C Consortium, Version 1, Second Edition, October 2000, ©W3C may also be used. The collection of all such publicly available computer files is known as the World Wide Web (WWW). The WWW is a multimedia-enabled hypertext system used for navigating the Internet and is made up of hundreds of thousands of web pages with images and text and video files, which can be displayed on a computer monitor. Each web page can have connections to other pages, which may be located on any computer connected to the Internet.  
         [0067]     A typical Internet user uses a client program called a “Web Browser” to connect to the Internet. A user can connect to the Internet via a proprietary network, such as America Online or CompuServe, or via an Internet Service Provider, e.g., Earthlink. The web browser may run on any computer connected to the Internet. Currently, various browsers are available of which two prominent browsers are Netscape Navigator and Microsoft Internet Explorer.  
         [0068]     The Web Browser receives and sends requests to a web server and acquires information from the WWW. A web server is a program that, upon receipt of a request, sends the requested data to the requesting user.  
         [0069]     A standard naming convention known as Uniform Resource Locator (“URL”) has been adopted to represent hypermedia links and links to network services. Most files or services can be represented with a URL. URLs also enable two programs on two separate computers to communicate with each other through simple object access protocol (“SOAP”), extensible markup language (“XML”), and other protocols published by the W3C consortium, incorporated herein by reference in its entirety.  
         [0070]     URLs enable Web Browsers to go directly to any file held on any WWW server. Information from the WWW is accessed using well-known protocols, including the Hypertext Transport Protocol (“HTTP”), the Wide Area Information Service (“WAIS”) and the File Transport Protocol (“FTP”), over TCP/IP protocol. The transfer format for standard WWW pages is Hypertext Transfer Protocol (HTTP). It is noteworthy that the invention is not limited to standard WWW or W3C protocols for server access and information exchange.  
         [0071]     Process Flow:  
         [0072]      FIGS. 2-5  show flow diagrams of computer-executable process steps according to the present invention for monitoring aircraft status. The process steps may be executed using a computing system, for example, system  10 . In one aspect, an independent data point (for example, ACARS message  108 ) is used by NOC  105  to determine when an aircraft should be joining a network monitoring system, for example, flight data center  105 A. Retroactive action may be taken if the aircraft does not join data center  105 A within a set threshold period. The threshold period may be programmed and can vary from one type of aircraft to another.  
         [0073]     Turning in detail to  FIG. 2 , in step S 200  message  108 A (ACARS (INT)) (or  108 B) is received by data center  105 A. Message  108 A (or  108 B) is received by receiving module  105 C in NOC  105 . Based on message  108 A, NOC  105  can estimate when aircraft  102 A should be joining (i.e. communicating in-flight messages) data center  105 A.  
         [0074]     In step S 202 , NOC  105  sends a status message to the airline or any other entity that has interest in monitoring the flight status of aircraft  102 A.  
         [0075]     In  FIG. 3 , in step S 300 , data center  105 A receives ACARS message  108 B notifying data center  105 A that the gate at the departure airport has been closed. In step S 301 , NOC  105  sends an updated status message (i.e., update from step S 202 ,  FIG. 2 ) via output module  105 E.  
         [0076]     Based on  FIG. 2  and  3  process steps, data center  105 A is aware of when an aircraft should be joining NOC  105 . As shown in  FIG. 4 , in step S 400 , NOC  105  determines if aircraft  102 A has joined. This is based on the ACARS messages  108 A and/or  108 B, which are independent of data center  105 A. NOC  105  searches for aircraft  102 A based on the ACARS message  108 A (or  108 B).  
         [0077]     If aircraft  102 A does not join NOC  105  in step S 400 , then in step S 401 , the process sends a message to a competent entity to start investigating why aircraft  102 A failed to join NOC  105 . Various tools may be used to start the investigation, for example, an email or instant message may be sent to the airline, via Internet  101  to seek further clarification on the status. The airline can then send an electronic message to aircraft  102 A. It is noteworthy that encrypted and secured messages may be used for electronic communication. Also, if authorized, data center  105 A may directly send a message to aircraft  102 A via Internet  101 . ACARS  108 A may also be correlated with real-time data  104 A, to ascertain the potential failure in step S 400 .  
         [0078]     If aircraft  102 A joins in step S 400  then in step S 402 , NOC  105  sends an updated message to the airline or any other entity.  
         [0079]     As shown in  FIG. 5 , in step S 500 , data center  105 A continues to monitor flight data for aircraft  102 A. This includes receiving various data points, as discussed above.  
         [0080]     In step S 501 , data center  105 A receives message  108 D, when the plane lands. In step S 502 , NOC  105  determines (using processing module  105 D) if aircraft  102 A landed within a certain window of time to ascertain if aircraft  102 A arrived on time. If aircraft  102 A arrived on time (or time window) then in step S 503  the status of aircraft  102 A is updated.  
         [0081]     If there is a deviation in aircraft  102 A arrival time, i.e., if it arrived too soon or too late, then the process triggers an investigation in step S 504 . The investigation is conducted to determine the cause for early arrival or delay. Again data  104 A,  109  and  110  may be used to determine the cause for such deviation. A message may be sent to the airline or aircraft  102 A, or any other entity involved in the flight. The message may be sent using Internet  101 .  
         [0082]      FIG. 6  shows a screen shot of a status screen, as provided by NOC  105 , in one aspect of the present invention. This report is accessible for an authorized entity, for example, an airline, a partner or customer.  
         [0083]     Various report formats are made available, based on an end-user&#39;s needs. For example, window  600  shows the geographic region where Internet access was provided on aircraft  102 A to passengers. Window  601  provides a listing of cases with abnormal flight patterns, based on the severity of the cases. Window  601  shows that flight 8914 experienced an 8-minute unplanned signal loss. Window  602  provides a graphical display of ‘high severity” reports based on time.  
         [0084]     Window  603  shows a listing of all support cases by a customer and window  604  shows a listing of all orders for a customer. The reports in  FIG. 6  may be produced using output module  105 E and can be used for various logistical and preventive maintenance purposes.  
         [0085]     In one aspect, the present invention provides a flight operations data system that utilizes the Internet to receive data from and send messages to an aircraft. The present invention provides flight operations data system that receives information from existing aircraft reporting systems, and may utilize this information to predict the status of an aircraft. The present invention, in yet another aspect, provides an improved flight operations data system that utilizes the Internet to receive data from and send messages to an aircraft in conjunction with existing aircraft reporting systems to enhance the data available to an airline company or any other entity.  
         [0086]     In yet another aspect, an improved flight operations data system is connected to a Network Operating Center that continuously monitors the status of the aircraft in real-time, either directly or in conjunction with any existing aircraft reporting system on the aircraft.  
         [0087]      FIG. 7  flow diagram shows process steps for monitoring ad-hoc network node(s)  102 B in a generic sense. In step S 700 , data center  105 A receives initial node status, for example, ACARSINT  108 A described above, or a train/boat&#39;s departure. In step S 701 , the process determines when node  102 B will join the ad-hoc network (Internet  101  and/or data center  105 A). In step S 702 , the process monitors node  102 B. Status of node  102 B may be provided from time to time, similar to the status provided with respect to an aircraft described above with respect to  FIGS. 2-6 .  
         [0088]     Those skilled in the art will appreciate that there are adaptations and modifications of the just-described preferred embodiments that can be configured without departing from the scope and spirit of the invention. Therefore, it is to be understood, that within the scope of the intended claims, the invention may be practiced other than is specifically described herein.