Abstract:
An automotive vehicle includes one or more computers. The one or more computers are configured to, in a first mode of operation, receive and store, at a plurality of instances, inventory information about assets in a vicinity of the vehicle, and identify patterns in asset inventories based on the inventory information and a history of vehicle locations associated with the inventory information. The one or more computers are also configured to, in a second mode of operation, generate output representing at least one suggested vehicle destination based on the identified patterns and assets detected in the vicinity of the vehicle.

Description:
BACKGROUND 
       [0001]    Several systems and techniques are known for electronically monitoring material assets. U.S. Pat. No. 7,151,454 to Washington, as an example, provides systems and methods that may be employed to visually locate and/or track objects equipped with active radio frequency identification (RFID) tags. The systems and methods may employ an articulated camera, such as closed circuit television or other suitable type of articulated camera, that is equipped with an antenna array. 
         [0002]    U.S. Pat. No. 7,138,916 to Schwartz et al., as another example, provides a computerized system to inventory articles, and to locate and recover lost or stolen articles. The system applies an electronic tag to each article of a multiplicity of articles, or only to a valuable article, and employs a computer to maintain an inventory of all articles. Use is made of a global positioning system to locate a lost or stolen article as well as to track movements of the article. A history of the movement of the article may also be plotted on a map. An electronic geographic boundary area may also be placed around an article that can be used to emit a signal indicative of the article leaving the area. 
         [0003]    U.S. Pat. No. 7,123,149 to Nowak et al., as yet another example, provides an integrated system for tracking assets and personnel associated with a work site. Personnel are equipped with tracking devices having at least geo-location capability. Assets are tagged with radio frequency identification (RFID) tags, which are interrogated at portals, by mobile scanners, or by personnel tracking devices having RFID reading capability. The tag readers and tracking devices are all in communication with a common “information backbone” and all data is delivered to, and processed by, a common command and control subsystem. 
       SUMMARY 
       [0004]    An automotive vehicle includes one or more computers. The one or more computers are configured to, in a first mode of operation, receive and store, at a plurality of instances, inventory information about assets in a vicinity of the vehicle, and identify patterns in asset inventories based on the inventory information and a history of vehicle locations associated with the inventory information. The one or more computers are also configured to, in a second mode of operation, generate output representing at least one suggested vehicle destination based on the identified patterns and assets detected in the vicinity of the vehicle. 
         [0005]    An automotive vehicle includes one or more radio frequency receivers configured to detect signals generated by activated wireless identification tags in a vicinity of the vehicle. The signals represent identifiers embedded in the wireless identification tags. The vehicle also includes one or more computers in communication with the receivers. The one or more computers are configured to, in a first mode of operation, record occurrences of detected identifiers, and identify a set of two or more tags based on the recorded occurrences. The two or more tags having been together within the vicinity of the vehicle on more than a predetermined number of occasions. The one or more computers are also configured to, in a second mode of operation, determine whether a particular detected tag belongs to the identified set, and determine whether other tags belonging to the identified set are also detected in the vicinity of the vehicle. 
         [0006]    While example embodiments in accordance with the invention are illustrated and disclosed, such disclosure should not be construed to limit the claims. It is anticipated that various modifications and alternative designs may be made without departing from the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a schematic diagram of an embodiment of an asset management system. 
           [0008]      FIG. 2  is a schematic diagram of an example user interface of the system of  FIG. 1 . 
           [0009]      FIG. 3  is another schematic diagram of the system of  FIG. 1 . 
           [0010]      FIG. 4  depicts an example data structure used by the system of  FIG. 1 . 
           [0011]      FIG. 5  is a schematic diagram of another example user interface of the system of  FIG. 1 . 
           [0012]      FIG. 6  depicts another example data structure used by the system of  FIG. 1 . 
           [0013]      FIG. 7  is a schematic diagram of yet another example user interface of the system of  FIG. 1 . 
           [0014]      FIG. 8  depicts yet another example data structure used by the system of  FIG. 1 . 
           [0015]      FIG. 9  is a flow chart depicting an embodiment of an algorithm for selecting and tracking assets. 
           [0016]      FIG. 10  is a schematic diagram illustrating the flow of data during the execution of a portion of the algorithm of  FIG. 9 . 
           [0017]      FIG. 11  is another schematic diagram illustrating the flow of data during the execution of another portion of the algorithm of  FIG. 9 . 
           [0018]      FIG. 12  depicts still yet another example data structure used by the system of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    Referring now to  FIG. 1 , a vehicle  8  includes an asset selecting and tracking system  10 . The system  10  includes a computer data processing unit  12  in communication with antennae  14   n . A receiver, transmitter or transceiver (not shown) may be the interface between the processing unit  12  and antennae  14   n . (As used herein, a transceiver may include a receiver and a transmitter.) The antennae  14   n  enable communication with wireless asset tracking technology. As an example, under the command of the processing unit  12 , the antennae  14   n  may generate signals in the radio frequency spectrum. The signals may excite circuitry in the form of radio frequency identification (RFID) tags affixed to various assets, e.g., tools, computers, sports equipment, etc. The excited circuitry may generate response signals in the radio frequency spectrum for detection by the antennae  14   n  and processing by the processing unit  12 . 
         [0020]    In some embodiments (such as the embodiment of  FIG. 1 ), the processing unit  12  and antennae  14   n  reside within a vehicle. In other embodiments, the processing unit  12  resides within a vehicle and the antennae  14   n  reside within a trailer, tool box or other location remote from the vehicle. In still other embodiments, the processing unit  12  resides within a location remote from the vehicle and the antennae  14   n  reside within the vehicle. Other arrangements are also possible. 
         [0021]    A computer  18  and the system  10  may communicate via a communication link facilitated by an Internet  20 , server  22 , network  25  (such as the public switched telephone network or PSTN), cellular network  26 , cellular transceiver  28  and modem(s)  30 . As an example, information from the computer  18  passes through the Internet  20  before it is received at the server  22 . The server  22  is configured with software that permits the computer  18  to access the system  10 . The server  22  stores and retrieves data from a database  23 . Information from the server  22  may be transmitted to the cellular network  26  via the network  25 . The cellular network  26  may then broadcast the information, depending on the communication technique. Signals received by the cellular transceiver  28  may be demodulated at the modem(s)  30  before processing by the processing unit  12 . 
         [0022]    A cell phone  32  and the system  10  may communicate via a communication link facilitated by a radio frequency transceiver  34 , such as a BLUETOOTH transceiver. As an example, information transmitted by the cell phone  32  is received by the transceiver  34  and demodulated by the modem(s)  30  before processing by the processing unit  12 . Outgoing information may also be communicated to the cellular network  26  via the cell phone  32  at link  36 . Alternatively, the cellular transceiver  28  and modem(s)  30  may be integrated with the system  10  for communication with the cellular network  26 . 
         [0023]    A mobile computer  38  and the system  10  may communicate via a wireless communication link facilitated by the transceiver  34 . As an example, information transmitted by the mobile computer  38  is received by the transceiver  34  and demodulated by the modem(s)  30  before processing by the processing unit  12 . As another example, the mobile computer  38  and the system  10  may communicate over a hard wire communication link via ETHERNET or Universal Serial Bus (USB). 
         [0024]    The system  10  may be accessed from any of example interfaces  16   a - 16   d  associated with the computer  18 , vehicle  8 , cell phone  32  and mobile computer  38  respectively. As an example, a foreman accessing the system  10  via the interface  16   a  may query the vehicle  8  as to its location. The system  10  may access an on-board navigation system that includes a receiver  41  capable of receiving signals from a satellite  42  that permit the processing unit  12  to determine its geographic location based on the received signals. The system  10  then responds to the query from the foreman with the geographic location information. The foreman may then assign a job to a construction crew using (or otherwise associated with) the vehicle  8 . In response, the system  10  performs a scan of the vehicle  8  to determine whether some or all required assets are present and/or missing. The system  10  informs the foreman of the presence of the assets. Alternatively, the system  10  may inform the construction crew, via the interface  16   b , of present/missing assets, or instruct the crew to acquire the missing assets. The system  10  may also inform a supervisor, via the interface  16   c , that the foreman has assigned the construction crew using the vehicle  8  a particular job, and that the vehicle  8  includes or is missing certain assets required to perform the job. 
         [0025]    As another example, a crew chief accessing the system  10  via the interface  16   b  may query a fleet of vehicles, each equipped with its own asset selecting and tracking system, regarding whether they have the required assets to perform a selected job. In response, each of the fleet vehicles performs its own scan of the assets within its vicinity and reports the results of the scan to the server  22  for access by the crew chief via the interface  16   b.    
         [0026]    As still yet another example, a construction worker accessing the system  10  via the interface  16   b  may select a job to be performed that day. The selected job information is communicated to a remote processing unit, such as the server  22 , via the communication techniques described above. The server  22  determines the required assets for the job. The required asset information is then communicated to the vehicle  8  along with a command to activate the antennae  14   n  to scan the vehicle  8 . The results of the scan are communicated back to the server  22 . The server  22  determines if any required assets are missing. This information is communicated to the vehicle  8  and displayed via the display  16   b . Other scenarios are also possible. 
         [0027]    The system  10  may identify assets for a selected job and monitor whether those assets are within a vicinity of the antennae  14   n . If any of the assets within the vicinity of the antennae  14   n  “leave” the vicinity of the antennae  14   n , the system  10  may alert a user. As an example, the system  10  may send a message to the cell phone  32 , either by the cellular network  26  or BLUETOOTH, indicating that a tool has left the vicinity of the antennae  14   n . As another example, the system  10  may activate an alarm system associated with the vehicle  8 . As yet another example, a paging signal may be communicated to a key fob (not shown) associated with the vehicle  8 . 
         [0028]    The system  10  may also periodically inventory the assets that are within a vicinity of the antennae  14   n  and compare that inventory to inventories taken at other times. If the system  10  detects differences between the inventories, the system  10  may alert a user. As an example, the system  10  may send a message to the computer  18  indicating that there are differences between an earlier and later performed inventory. This may be performed, for example, when leaving a job site to ensure that no tools are inadvertently left behind 
         [0029]    The system  10  may further record the geographic location of the vehicle  8  when the inventory occurred using information from the navigation system discussed above. As explained below, certain embodiments of the system  10  may use this location and inventory information to learn which assets are taken to particular locations. The system  10  may then suggest possible vehicle destinations based on the presence of certain assets within the vehicle  8  at, for example, vehicle start-up. 
         [0030]    Inventories may be performed at specified intervals or upon the occurrence of specified events. As an example, a user may configure the system  10  to perform an inventory once every hour and at vehicle start-up. As another example, the system  10  may perform an inventory in response to a user pressing a button (not shown) on a key fob or console of the vehicle  8 . Such configuration information may be entered via any of the interfaces  16   a - 16   d.    
         [0031]    Referring now to  FIG. 2 , a “Framing” job/task has been entered into one of the interfaces  16   n . In response, the system  10  has identified a “Drill,” “Hammer,” “Level” and “Nail Gun” as predefined assets required for the “Framing” job/task. The system  10  has also identified that the “Drill” and “Hammer” are currently located in a “Bed” of the vehicle  8  and that the “Level” is currently located in a “Cabin” of the vehicle  8 . The system  10  has further identified that the “Nail Gun” is missing. 
         [0032]    In other embodiments, the information of  FIG. 2  may be displayed for multiple vehicles. As an example, a user of the computer  18  may access a fleet of vehicles equipped with asset selecting and tracking systems, such as the system  10  of  FIG. 1 , to assign jobs/tasks, and query each vehicle as to whether it has the required assets to perform the assigned job/task. The server  22 , acting as a communication hub with the fleet of vehicles, collects the asset information from each of the fleet vehicles and stores it in the database  23 . The server  22  may then create a master view of the fleet vehicles on a single screen, e.g., the display  16   a , that shows, for each vehicle, the assigned job/task and required, present and missing asset information. 
         [0033]    Referring now to  FIG. 3 , the antennae  14   a - 14   f  are positioned throughout the vehicle  8 . The antennae  14   a  and  14   b  are positioned to monitor the front and rear of the vehicle  8  respectively. The antennae  14   c  and  14   d  are positioned to monitor respective sides of the vehicle  8 . The antenna  14   e  is positioned to monitor a cabin  44  of the vehicle  8 . The antenna  14   f  is positioned to monitor a bed  46  of the vehicle  8 . In other embodiments, the antennae  14   n  may be positioned as desired. As an example, one of the antennae  14   n  may be removed from the vehicle  8  and placed, for example, at a work site. 
         [0034]    Referring now to  FIG. 4 , a data structure  48  stored within a memory  49  of the processing unit  12  maps each of the antennae  14   n  with a respective location about the vehicle  8  (or jobsite, if remote antennae are used). In the example of  FIG. 4 , the antenna  14   a  monitors the front of the vehicle  8 , the antenna  14   b  monitors the rear of the vehicle  8 , and so on. The data structure  48  allows the system  10  to translate between a signal received from one of the antennae  14   n  and its location about the vehicle  8 . 
         [0035]    Referring again to  FIG. 3 , the antennae  14   n  have a communication module for communicating with the processing unit  12  via a controller area network (CAN). Commands from the processing unit  12  and responses from the antennae  14   n  are broadcast on the CAN for receipt by the antennae  14   n  and processing unit  12  respectively. In other examples, the processing unit  12  and antennae  14   n  may communicate directly via a hard wire connection. In still other examples, the processing unit  12  and antennae  14   n  may communicate via a wireless connection. Such wireless connections may be particularly suitable for antennae  14   n  configured to be removed from the vehicle  8  and placed, for example, at a work site. Such wireless connections may also be particularly suitable for circumstances where the processing unit  12  is remote from the vehicle  8 . 
         [0036]    Referring now to  FIG. 5 , a set-up mode allows a user to configure the system  10  to recognize a certain set of assets tagged with wireless identification tags. The interface  16   n  prompts the user to enter a description of an asset with such a tag. In the example of  FIG. 5 , the user has entered “Drill.” The user then places the “Drill” in the vehicle  8  and selects the “SCAN” button on the interface  16   n . The user continues this process until all assets have been entered. In other embodiments, the interface  16   n  may prompt the user to enter a tagged asset and an identification code associated with the tagged asset, thus avoiding the scanning step. In still other embodiments, the user may be prompted to enter an identification code associated with a tagged asset and to select, from a list, a description of an asset to be associated with the identification code. Other configuration methods are also possible. 
         [0037]    Referring now to  FIG. 6 , the system  10  creates a data structure  50  that maps each of the identification codes of the tags with its respective asset description as a result of the process described with reference to  FIG. 5 . The data structure  50  may be stored in the memory  49  of the processing unit  12 . In the example of  FIG. 6 , the identification code “3X1” corresponds to the “Drill,” the identification code “4B2” corresponds to the “Hammer,” and so on. The data structure  50  allows the system  10  to translate between the identification codes and the asset descriptions. 
         [0038]    Referring now to  FIG. 7 , the set-up mode also allows the user to configure the system  10  to identify assets necessary for a given job/task. The system  10  prompts the user, via the interface  16   n , to enter a job/task. In the example of  FIG. 7 , the user has entered “Framing.” The interface  16   n  provides a set of assets that may be selected by the user. The user has selected the “Drill,” “Hammer,” “Level” and “Nail Gun” by clicking on the circular fields provided. The user continues this process until all the jobs/tasks have been created. In other embodiments, the interface  16   n  may prompt the user to enter a job/task and a set of assets required for that job/task. In still other embodiments, the system  10  may be pre-loaded with a set of jobs/tasks and associated assets. These pre-loaded settings may be modified by the user. Other configuration methods are also possible. 
         [0039]    Referring now to  FIG. 8 , the system  10  creates a data structure  52  that maps each of the asset descriptions with its respective job/task as a result of the process described with reference to  FIG. 7 . The data structure  52  is stored in the memory  49  of the processing unit  12  or alternatively, in the database  23  of the server  22  illustrated in  FIG. 1 . In the example of  FIG. 8 , the “Drill” corresponds to the jobs/tasks “Framing” and “Drywall,” the “Hammer” corresponds to “All” jobs/tasks and so on. The data structure  52  allows the system  10  to translate between the asset descriptions and the jobs/tasks. 
         [0040]    Referring now to  FIG. 9 , a user may access the system  10  to determine whether the assets required for a particular job/task are in a vicinity of the vehicle  8 . At step  54  the user is prompted to input a job/task into the system  10 . At step  56 , the system identifies assets assigned to the job/task input at step  54 . At step  58 , the system inquires as to the assets in the vicinity of the vehicle  8 . At step  60 , results of the inquiry are reported to the user. 
         [0041]    Referring now to  FIG. 10 , the job/task “Framing” has been input into the system  10  via the interface  16   n . The system  10  identifies the assets required for the job/task “Framing” via the data structure  52 . The system  10  also determines which assets, if any, are in a vicinity of the vehicle  8  by activating the antennae  14   n.    
         [0042]    Referring again to  FIG. 3 , the antennae  14   n  transmit signals (as indicated by dashed lines) capable of exciting circuitry associated with any wireless identification tags. In the embodiment of  FIG. 3 , tools  62 ,  64 ,  66  having tags with the identification codes “3X1,” “4B2” and “7C3” respectively are in a vicinity of the vehicle  8 . In response to the signals transmitted by the antennae  14   n , circuitry associated with each of the tags of the tools  62 ,  64 ,  66  generate a response signal representing their identification code. As an example, the circuitry associated with the tag of the tool  62  generates a response signal representing the identification code “3X1.” 
         [0043]    As explained above, each of the antennae  14   n  are tuned to monitor a specified region about the vehicle  8 . As an example, the antenna  14   e  is tuned to monitor the cabin  44  of the vehicle  8 , and the antenna  14   f  is tuned to monitor the bed  46  of the vehicle  8 . Because of the location of the tools  62 ,  64 ,  66 , the antenna  14   f  receives the response signals generated by the tags of the tools  62 ,  64 , and the antenna  14   e  receives the response signal generated by the tag of the tool  66 . 
         [0044]    Referring now to  FIG. 11 , the system  10  determines the location associated with each of the response signals via the data structure  48 . The system  10  also determines the description associated with each of the identification codes of the response signals via the data structure  50 . 
         [0045]    Referring again to  FIGS. 2 ,  10  and  11 , a comparison performed by the system  10  of the assets identified for the job/task “Framing”, i.e., “Drill,” “Hammer,” “Level” and “Nail Gun,” with the assets located in the vicinity of the vehicle  8 , i.e., “Drill,” “Hammer” and “Level,” reveals that the “Nail Gun” is missing from the vehicle  8 . The information regarding the assets is provided via the display  16   n.    
         [0046]    Referring again to  FIG. 1 , the system  10 , in still other embodiments, may learn (while in a learning mode) which assets are typically in the vicinity of the vehicle  8  on particular days, times and/or locations. The system  10  may also learn, as mentioned above, which assets are typically taken to particular destinations, etc. This learning mode may be initiated via user input or other suitable initiation scheme. The system  10  may, for example, inventory assets in the vicinity of the vehicle  8  upon vehicle start-up (upon vehicle shut-down, upon user request, etc.) for a specified (e.g., user specified) number of days. The system  10  may then analyze this inventory information to identify asset patterns based on, for example, day, time and/or vehicle location, etc. 
         [0047]    With such learned information, the system  10  may, for example, generate an alert if an asset expected to be in the vicinity of the vehicle  8  is missing. The system  10  may also suggest, via the navigation system discussed above, potential vehicle destinations based on the presence of a certain asset (or combination of assets). 
         [0048]    Referring now to  FIGS. 1 and 12 , the system  10  has created an example data structure  68  capturing the date, time, location, and assets detected upon vehicle start-up during a five-day period. (Any suitable data collected during any suitable time period, however, may be used.) The data in this example reveals that (1) on Monday, Wednesday and Friday, “computer” is in the vicinity of the vehicle  8  (e.g., in the vehicle  8 ) upon vehicle start-up around 8:00 am (presumably the time at which the user leaves for work); and, (2) on Tuesday and Thursday, “computer” and “widget” are in the vicinity of the vehicle  8  (e.g., in the vehicle  8 ) around the same time. (As apparent to those of ordinary skill, location data may be obtained from the navigation system discussed with reference to  FIG. 1 ; time and/or date data may be obtained from a clock internal to the vehicle  8  or the navigation system, etc. Of course, any suitable technique may be used to obtain such information.) 
         [0049]    Pre-defined (or user defined) rules may be used, in certain embodiments, to identify asset patterns within the data structure  68 . The rules may be preloaded in the system  10 , or input via the interfaces  16   n  and stored in a memory accessible by the processing unit  12 . These patterns may reveal, for example, which assets are typically in the vicinity of the vehicle  8  during early weekday mornings, which assets are typically in the vicinity of the vehicle  8  on Saturday mornings, which assets are typically taken to work, and which sets of assets are typically taken to particular destinations, etc. 
         [0050]    A first rule, for example, may be used to tally the number of times a given asset at a given location was detected during weekday mornings between the hours of 7:00 am and 9:00 am (other time periods and/or rules, of course, may also be used). In the example of  FIG. 12 , “computer” was detected five times and “widget” was detected two times. A second rule may be used to determine whether the number of times a given asset was detected exceeds a threshold (e.g., four times). In the example of  FIG. 12 , the number of times “computer” was detected (i.e., five) exceeds the example threshold (i.e., four). The system  10  has thus learned (or expects) that on weekday mornings between the hours of 7:00 am and 9:00 am, when the vehicle  8  is “home,” “computer” should be in the vicinity of the vehicle  8 . If on a subsequent Monday (when the system  10  is no longer in learning mode) between the hours of 7:00 am and 9:00 am, “computer” is not detected in the vicinity of the vehicle  8  (and the vehicle  8  is “home”), the system  10  may generate an alert, using any suitable technique, to inform the user via the interfaces  16   n  that “computer” is missing (upon, for example, vehicle start-up). 
         [0051]    Destination data (from the navigation system discussed above) may also be recorded in a data structure similar to the data structure  68  of  FIG. 12  so that the system  10  may learn which assets are taken to certain destinations. (The system  10  may also simply track destination and assets detected, etc., while in learning mode.) In the example above, the day, time, vehicle location, and detected assets are recorded in the data structure  68  upon vehicle start-up. Assuming that the vehicle location at subsequent vehicle shut-down was also recorded (and assuming that location was “work”), rules similar to those discussed above could be constructed to allow the system  10  to learn that “computer” is normally taken to “work.” For example, a rule may be used to tally the number of times a given asset was taken to “work” during five consecutive weekdays. Another rule may be used to determine whether the number of times a given asset was taken to “work” exceeds a threshold. If, when the system  10  is no longer in learning mode, “computer” is missing when the user informs the navigation system that he is going to “work,” the system  10  may generate an appropriate alert. 
         [0052]    Rules may also be constructed that permit the system  10  to suggest a list of potential destinations based on assets that are detected in the vehicle  8 . For example, as discussed above, once the system  10  has learned that “computer” is taken to “work,” a rule may be constructed that prompts the user with a question, via the interface  16   n , asking if the intended destination is “work” if “computer” is detected in the vehicle  8 . As another example, if “golf clubs” are detected, a rule may be constructed to prompt the user with a question asking if “golf course” is the intended destination, etc. As yet another example, if the system  10  has learned that “golf clubs” and “golf shoes” are typically in the vehicle  8  at the same time, if “golf clubs” are placed in the vehicle  8  (but not “golf shoes”), the system  10  may warn the user that “golf shoes” are not in the vehicle  8 . For example, a rule may tally the number of times two or more assets are in the vehicle  8  at the same time (on different occasions). A second rule may determine whether the number of times the two or more assets were in the vehicle  8  at the same time exceeds a threshold. A third rule may prompt the system  10  to determine if all of the two or more assets are detected in the vehicle  8  if any one of the two or more assets are detected. A fourth rule may prompt the system  10  to generate an alert identifying any of the two or more assets that are missing, etc. 
         [0053]    Additional rules may be implemented to refine/augment the learning capabilities of the system  10 . A rule, for example, may determine whether the user has input, via the interface  16   n , a negative response to the alert mentioned above. If so, the system  10  may discontinue such alerts even if an asset expected to be in the vicinity of the vehicle  8  is absent. Other scenarios are also possible. 
         [0054]    Analytical techniques may also be used, in other embodiments, to identify asset patterns. For example, the system  10  may implement a neural network that monitors data similar to that discussed with reference to  FIG. 12  to learn, in a known fashion, which assets should be in the vicinity of the vehicle  8  during certain days, times and/or locations, which assets are typically in the vehicle  8  at the same time, etc. 
         [0055]    While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.