Software Requirements Specification Template
Contents
1. writers and users involved in sensor networks domain to initiate an open discussion for exploring development opportunities regarding self configuration of sensor services Section 2 discusses the steps that are to be undertaken to avail the self configuration feature In the next section system features with their functional requirements are presented to highlight the major services provided by the intended product Then the external interface requirements highlighting the logical characteristics of each interface between the software product and the users are discussed Finally this specification is concluded with the reference documents on which this document is based on 1 4 Project Scope The final product enabling the self configuration feature will assist a sensor network service to dynamically adapt to the changing environment including the deployment of new components or the removal of existing ones or sudden changes in the system characteristics These variations can happen either as random periodic events or gradual evolutionary changes in the system The underlying principle for building self configuring sensor network services is to provide fundamental mechanisms upon which other networking and system services may be spontaneously specified and reconfigured To make a sensor network service self configurable the following conditions must be met e The tasks involved in the configuration of a service are automated e The automation2. Software Requirements Specification for Semantics based Publish Subscribe System for Self Configuration of Sensor Networks Services Version 1 0 Prepared by Mukaddim Pathan CSIRO ICT Centre 108 North Road Acton ACT 2601 20 February 2011 Software Requirements Specification for Semantics based Publish Subscribe System Page ii Table of Contents Tablic oi C OMGCIIG naian a cacucencacenc ice a il Revision History occa seis cecccssaechantahcesicte Tacs a aea aa aaaea il l MAVGR OC UCU OM 5 eicsseccasesyeccntesiackxcneaceaeneseccaenceeeen eats acca ca Se aeeeaeie Sate adek aaa ENETREEERR 1 1 1 PUDO a T E ats Ca etacihcint 2636 salad aausnnad ta oe tat th aada la imaatnan l 1 2 Doomen COI CHUIONNS seen a A A A l 1 3 Intended Audience and Reading Suggestions cccccccccccsssseccccccececccceccceeceeeeceeceececeeeeeeeeeeees l 1 4 POCO DECODE meene E S A A AS 2 1 5 RETE NCE S eira Re E enters ee en ane ree oe 2 De Overall DOS CHIP O ascris ansaa a sta actevesacddedenieieesetecsees staacivessactdedenieeyeneteserees 2 2A Product PETS PC CU VG carenes iio E ane ee 2 22 Product REU CS anea e a A E E T E S Meo eee ES 3 23 User Classes Amd CMaraC tem SUC recerca a Suassauenens eeeeacarecees 4 2 4 Operating EnVrONMEN sisanne a a a ak tates Raab ean ea 4 2 5 Design and Implementation Constraints i405 c0 icansdsadediaascivinnedecteeeaeeak Sqnedsad teense anedes ei eaeeaaneeentes 5 2 6 User Docume LAL ON gs cass assulsnhce dco N a outer
3. behavior is defined by the activities that execute service actions It can be assumed that that the state of a sensor service is observable and that the results of actions influence the observables and state variables Service types are specified in terms of one or more interfaces whereby one interface may be attached to several configurations An interface characterizes the behavior of a service and enables a common approach to represent the capabilities of a sensor service Interfaces should be considered as the unit of reusability A self configurable service in the Semantic Pub Sub system could be represented by a tuple lt C V T gt where e C is the set of code blocks to perform service functionality l x P where is the set of inputs and p is the set of outputs of a sensor network service and J defines a valid input output set A code block c C makes use of state variables v V Code blocks in the system are invoked through system operations t T One operation can invoke several code blocks e V is the set of state variables in the system accessed through the code blocks It can be expressed as lt 0 Y gt where ois the set of sensors to provide services and yis the set of constraints set that controls access to the sensor and its services Constraints are based on state and or context and can control who invokes the sensor service when and how they are invoked and configured e Tis the set of operations for self con
4. communicate with client applications As an integral part of the product an ontology repository provides necessary information about the underlying sensor networks in terms of observations measurements and sensor capabilities The publish subscribe interactions well adapt to the needs of self configuration of sensor services Software Requirements Specification for Semantics based Publish Subscribe System Page 3 Application Specific q Network and System Client Services Applications lt Subscription gt Semantic Based Sensor Service Configurations Execute Sensor Network Self Configurable Physical Infrastructure Sensor Services Overlay Figure 1 Abstract architecture of Semantic Pub Sub Figure 1 shows an abstract architecture of the intended product Sensor network physical layer consists of heterogeneous sensor nodes placed at distributed locations The application specific network and system services sit on top of the physical infrastructure to provide routing location naming binding information dissemination and aggregation services When there are changes within the self configurable sensor services overlay the runtime information is fed into the related self configuration context ontology using a feedback mechanism The changes trigger the execution of self configuration logic for dynamic adaptation via monitoring analysis planning and execution Figure 1 The main goal of such a mec
5. in the registry 2 If it is a new Service its configuration is registered in the registry with a new service ID Service ID counter is incremented 3 Else resource information in registry is updated in a regular basis 4 When client application queries for service configurations information on available services along with their IDs is supplied to the AE 3 1 6 Exceptions If a sensor service fails its configuration information is removed from registry and the service ID counter is decremented 3 1 7 Functional Requirements REQ 1 The format for representation of service configuration is defined REQ 2 The interaction protocol between Sensor service registry registry AE is defined REQ 3 There is an established norm that any service failure will be reported 3 2 Querying of Service Configuration Subscription This feature relates to the initiation request from client application to get available service configuration from the Semantic Pub Sub system The use case for this feature 1s shown in Figure 4 Software Requirements Specification for Semantics based Publish Subscribe System Request for service configuration Client Application lt lt Actor gt gt AE Figure 4 Client application queries to retrieve service configuration Send query to retrieve service configuration 3 2 1 Actors Client application Requests for service configuration Page 8 AE Receives queries from client applicati
6. interfaces for gateway operation and communication will be used 4 3 Software Interfaces There will be a Web based interface for the intended product through which client applications can subscribe to the published service configurations and get notified Relevant Java libraries Java Server Faces Software Requirements Specification for Semantics based Publish Subscribe System Page 13 JSF or Java Server Pages JSP Tomcat server and MySQL databases will be used to make a complete concept demonstrator of the product Details of the software interface will be included as the product goes through full fledged development 4 4 Communications Interfaces Java Messaging Service JMS will be used to notify subscribing client applications RESTful Web services APIs will be exposed to communicate with the product and integrate into a deployed sensor network Details will be available over the development of the product 5 Other Nonfunctional Requirements 5 1 Performance Requirements The performance of the system will be tested under different scenarios and results will be demonstrated in terms of performance metrics such as response time scalability throughput etc Detailed performance evaluation will be carried out to demonstrate superior performance of the product 5 2 Software Quality Attributes Additional quality characteristics of the product may also be important to the customers or developers Some to consider are adaptability
7. moisture soil temperature and an infrared sensor measuring leaf temperature The plant scientists involved in this project are interested in comprehensive sensor readings based on a number of environment and water quality parameters to run on yield and measure performance after frost heat and drought Based on the observed data scientists are able to map microclimatic conditions such as light temperature and soil moisture across the field to better evaluate and compare new plant varieties By mapping these conditions and combining them with each plant s genetic profile and performance plant scientists can de convolve the effects of microclimate and genome thus improving the accuracy and speed of plant breeding Figure 2 shows an abstraction of the operating environment for the Semantic Pub Sub system identifying the software components assumptions and dependencies Section 2 7 Software Requirements Specification for Semantics based Publish Subscribe System Page 5 Cllents Clients Clients Management Application Semantic Pub Sub Mediation Components SSN Ontology Phenonet Sensor Network eS eS eS as DA Figure 2 Operating environment 2 5 Design and Implementation Constraints The Semantic Pub Sub system should formally capture the structural properties and run time behavior of a sensor network service The structure is defined by the service configurations and status in the system whereas the run time
8. process is initiated based on situations that can be observed or detected in the sensor network system e An authoritative entity in the sensor network must possess sufficient knowledge of sensor network service configuration resources policies and observed data On satisfying these conditions it 1s possible to assemble the automated functions in a set of composed processes to allow a sensor network service to be self configurable These processes can be governed to collect necessary details from the system analyze them to determine the required configuration changes for a sensor service create a plan or action sequence specifying the necessary changes and perform those actions 1 5 References This document builds on the following references e The architecture for self configuration of sensor network services 6 A description of Phenonet the application domain for the Semantic Pub Sub product 2 Semantic specification of sensors 1 and use of semantics for sensor network programming 7 Methods for computing difference of ontology versions 3 4 Semantic based service framework for query processing 5 2 Overall Description 2 1 Product Perspective Development of the Semantic Pub Sub system the product being specified in this SRS requires to 1 define the service configuration in a standard machine readable format 11 publish the definition via a registry in order to make it discoverable and 111 support a protocol to
9. registration of sensor network services with the Semantic Pub Sub system The use case for this feature is shown in Figure 3 lt lt Actor gt gt Sensor Service Publish service configuration lt lt Actor gt gt Service Registry lt lt Actor gt gt AE Figure 3 Sensor service registration with Semantic Pub Sub Register services USES Update service configuration in registry Collect service configurations from registry Software Requirements Specification for Semantics based Publish Subscribe System Page 7 3 1 1 Actors Sensor service Publishes its configuration information to the registry Registry Registers available service configurations and updates them Authoritative Entity AE Collects up to date service configurations from registry 3 1 2 Trigger Service registration is triggered when either one of the following occurs a services are available as a deployed sensor network starts operating b previously registered service configuration needs to be updated and c new services are deployed in the system 3 1 3 Preconditions Available sensor network services are detected along with their configurations such as location type storage data transfer rate etc 3 1 4 Postconditions Sensor services are registered in the registry and being updated in a regular basis 3 1 5 Stimulus Response Sequences 1 Each sensor network services publishes its configuration
10. E Pass service configurations to client applications Figure 5 AE invokes initialization through providing configuration data to client application 3 3 1 Actors Registry Stores service information and sends to AE for delivering to client application AE Receives configuration data from registry 3 3 2 Trigger Upon receiving the query request to initiate semantic pub sub operation AE retrieves service configuration data and passes it to client application 3 3 3 Preconditions Query request is received 3 3 4 Postconditions Service configurations are retrieved and they are sent to client application 3 3 5 Stimulus Response Sequences 1 A query request to initialize semantic pub sub operation is received by AE 2 AE retrieves service information from the registry 3 AE passes configuration data to client applications 3 3 6 Exceptions If the query requests cannot be accepted as there is no matching to the stored service configurations client applications receive null 3 3 7 Functional Requirements REQ 1 The format of service configurations is defined REQ 2 AE registry AE client application interaction protocols are defined REQ 3 AE works in conjunction with the registry to establish semantic pub sub operations Software Requirements Specification for Semantics based Publish Subscribe System Page 10 3 4 Adaptation to Changes Operational Management This feature is responsible for adaptation of sensor netw
11. availability correctness flexibility interoperability maintainability portability reliability reusability robustness testability and usability These additional attributes will be elaborated as the product reaches maturity 6 References 1 M Compton C Henson H Neuhaus L Lefort and A Sheth A survey of the semantic specification of sensors Proc 2nd International Workshop on Semantic Sensor Networks SSN 09 2009 2 B Furbank X Sirault and D Deery Phenonet A distributed sensor network for field crop phenotyping Proc Ist International Plant Phenomics Symposium from Gene to Form and Function 2009 3 B Konev D Walther and F Wolter The logical difference problem for description logic terminologies Automated Reasoning Lecture Notes in Computer Science vol 5195 pp 259 274 2008 4 R Kontchakov F Wolter and M Zakharyaschev Can you tell the difference between DL Lite ontologies Proc 11th International Conference on Principles of Knowledge Representation and Reasoning pp 285 295 2008 5 L Li and K Taylor A framework for semantic sensor network services Proc International Conference on Service Oriented Computing ICSOC 08 pp 347 361 2008 6 M Pathan K Taylor and M Compton Semantics based plug and play configuration of sensor network services Proc 3rd International Workshop on Semantic Sensor Networks SSN 10 Springer 2010 7 K Taylor and P Penkala Usin
12. ctures via an event driven and standards based messaging engine the bus The reasons for using an ESB are increased flexibility decentralization faster integration to existing systems and distributed deployment WSO2 ESB provides a built in repository to store service configurations and metadata Alternatively Apache ActiveMQ an open source message broker that implements the Java Message Service JMS can also be used for message exchange related to Semantic Pub Sub A mediation component developed in Java will integrate the Semantic Pub Sub system with the Phenonet sensor network deployment In addition an open source Java framework called Sesame will be used for storage and querying of RDF data to enable the usage of RESTful Web services APIs 3 System Features The major services and functional requirements for the product can be illustrated by system features This section is organized by use cases for major system features In the following necessary description is provided for each use cases in the system Each use case description provides information of the associated actors triggering condition preconditions postconditions response sequences exceptions and functional requirements assumptions Being a major important section of the SRS this section is expected to go through iterative improvement to make the most logical sense for the intended product 3 1 Service Registration Publish This feature is associated with the
13. e is no subscribing client application the system is decommissioned under governance of AE Software Requirements Specification for Semantics based Publish Subscribe System Page 12 Semantic Pub Sub lt lt Actor gt gt Termination AE condition holds Decommission of the system Figure 7 Decommission of Semantic Pub Sub 3 5 6 Exceptions If there are exceptional circumstances such as natural disaster theft etc for which the deployed sensor network is affected the physical infrastructure is restored to continue operation 3 5 7 Functional Requirements REQ 1 Termination conditions are identified REQ 2 Administrative tasks of AE are established 4 External Interface Requirements 4 1 User Interfaces This section describes the logical characteristics of each interface between the intended software product and the users For user interface design common GUI standards will be followed along with the presence of keyboard shortcuts error message display standards etc and standard buttons and functions 1 e help will appear on every screen Details of the user interface design are intended to be documented in a separate user interface specification 4 2 Hardware Interfaces It is intended that the Semantic Pub Sub system will be deployed within the context of the Phenonet project Therefore relevant hardware interfaces for Fleck sensors will be used to program the deployed sensor nodes In addition common hardware
14. es from the sensor network and they query it to retrieve data The sensor network services may vary configuration as the result of environmental changes or other interesting phenomena The Semantic Pub Sub system supports this users running in conjunction with the network and data stores and match the right capabilities to client applications allowing them to add and remove subscriptions dynamically as the service configurations change In the following example scenarios detailing user characteristics are presented Scenario 1 Consider a standing query a conjunctive query over terms and properties from the ontology submitted by a client application that is checking for temperature threshold values in a sensor network The query represents interest in the data underlying the queried concepts In this case the observed properties can be sensor locations sensor accuracy and sensor manufacturer If any change occurs in some part of the network or the ontology itself on which the query is built the query will be required to change as well A client application would thus subscribe to concepts properties and named individuals in the query The system then monitors change to the ontology and service configuration and notifies subscribers of changes that logically or structurally affect them The dependence on a change can be direct or indirect implied since the ontology is a logical object Scenario 2 From the sensor network perspective a fundamenta
15. figuration that are executed by sequentially invoking code blocks in the system based on the system state changes by manipulating the system variables in V 2 6 User Documentation Along with the software product a user manual would be written to help people understand the working methodology and usage of the developed prototype system It would be written for non technical individuals and the level of content or terminology would differ considerably from for example a System Software Requirements Specification for Semantics based Publish Subscribe System Page 6 Administration Guide which is more detailed and complex The user manual would follow common user documentation styles capturing purpose and scope of the product along with key system features and operations step by step instructions for using the system including conventions messaging structures quick references tips for errors and malfunctions pointers to reference documents and glossary of terms 2 7 Assumptions and Dependencies This product would build on standards based semantic technologies In particular W3C SSN XG ontology will be used to represent the complete sensor network configuration expressed in the Web Ontology Language OWL A significant feature of the Semantic Pub Sub system will be its ability to support flexible subscriptions The product will be built using an Enterprise Service Bus ESB such as WSOZ2 It provides fundamental services for complex archite
16. from time to time They may subscribe interact to an alert service that provides information on the availability of relevant upgrades and decide for themselves when to apply the upgrade Decommission replacement Alternative to an upgrade process sensor network services for the Semantic Pub Sub system could be implemented afresh as part of a system upgrade removing outdated services only after the new ones obtain a proper working status Lifecycle management AE performs simultaneous activities to schedule and prioritize operations A user Software Requirements Specification for Semantics based Publish Subscribe System Page 4 interacts with a service via an appropriate interface provided by AE and retrieves the service description directly from the service As per the node composition rule the sensor service is configured and invoked according to application scenarios and context During the lifetime of the system services are dynamically reconfigured in response to sensed observations and system changes 2 3 User Classes and Characteristics The users of Semantic Pub Sub system are the publishers and subscribers Sensor network services belong to the first category who publishes service configurations expressed using the SSN XG ontology Subscribers are the applications from a number of clients such as scientists plant biologists environmental researchers plant breeders farmers and funding bodies Client applications require different servic
17. g Explicit Semantic Representations for User Programming of Sensor Devices Proc Australasian Ontology Workshop 2009
18. hanism is the decoupling of publishers and subscribers in time space and synchronization 2 2 Product Features The Semantic Pub Sub system can be featured with the following major lifecycle phases Implementation This phase involves service design testing and verification The runtime infrastructure should leverage distributed components to create an optimal configuration according to both application requirements and context It should also allow uniform access to data by applications irrespective of the data format source or location An ontology can be used to represent context and sensor capabilities Installing and configuring This phase involves bringing up a service to an operational state with minimal user involvement It requires explicitly stating a user subscription to correspond to a published configuration in a formal request language To enable this a sensor service will entail a bootstrapping process that begins with the configurations registering itself with the Semantic Pub Sub system Monitoring This phase is included in the self configuration management It involves monitoring configuration changes for sensor network services This is an essential stage for enabling self configuration ability for a service When coupled with event correlation or decision theory the monitored information is useful for problem identification and recovery during system faults Service upgrade Sensor network services may require upgrading them
19. his document describes the requirements specification SRS for the software infrastructure or product that enables the self configuration features in a sensor network deployment with the use of a semantic based publish subscribe component henceforth termed as Semantic Pub Sub It presents a means for a sensor network to enable autonomous structuring of contextual information and resources thus making them available to services It will allow service customization and support employing semantic technologies This document provides a basis for evaluating the proposal for a self configurable sensor network service This is the version 1 0 of the software requirements specification 1 2 Document Conventions When writing this SRS for Semantic Pub Sub the following terminologies are used Semantics Semantic technologies provide a machine understandable meaning of sensed data for automatic information processing and exchange Its use seeks to assist the integration of heterogeneous sensor resources that need to interoperate and support the automation of service configurations Ontology An ontology provides a medium for capturing and reusing the knowledge and experience gained from prior efforts it thus leads to a great level of automation at the semantic level It can be used to describe various aspects of a sensor network service and bridge the gap between services re usable in various scenarios and requirements in the context of an individua
20. l client application Self configuration It is a feature for sensor network services to autonomously adapt to application scenarios and context with enhanced accessibility and reusability Publisher A system component that publishes sensor service configuration modeled using the W3C SSN XG sensor ontology Subscriber Client applications that describes its interest as a module i e managed name topics of the ontology Registry By computing the ontology subsumption hierarchy with a reasoner the registry holds a topic hierarchy of classes and properties that 1s made available for subscription Authoritative Entity AE The central component of the Semantic Pub Sub system administering the operations of sensor network services Web Ontology Language OWL A knowledge representation language for authoring ontologies Abox It refers to an assertion component a fact associated with a terminological vocabulary within a knowledge base Grounded data about particular sensor service configurations are defined in OWL as Abox instances Tbox It refers to a terminological component a vocabulary associated with a set of facts Sensing concepts are defined in OWL as axioms in the Tbox 1 3 Intended Audience and Reading Suggestions This document is written for the researchers software developers advanced practitioners documentation Software Requirements Specification for Semantics based Publish Subscribe System Page 2
21. l example can be when the network is configured and programmed automatically using an ontology with the ontology treated as data loaded into a query interface If terms in the ontology are moved or redefined or if additions are made either to the ontology or the capabilities of the network the query interface and its associated compilation procedure will be notified and the reconfiguration will be reflected in the client interface to take advantage of the changes Scenario 3 An application service that allows the definition and automated orchestration of new sensors and services in terms of the concepts sensors and existing services in the ontology can work as part of the network configuration described above or by building compositions on top of the network s capabilities If the composite sensor application service is defined as a concept in the ontology the concepts and roles used in the definition and construction of a new sensor can subscribe to it If change occurs in any part of the ontology or network on which the new sensor depends the composition service can be notified to reconstruct the composite sensor from the updated definitions and network capabilities 2 4 Operating Environment The product in this SRS will be deployed within the context of the Phenonet project The project deploys a 40 node distributed sensor network to monitor crop growth The sensor network consists of sensors measuring solar radiation air temperature soil
22. on to retrieve relevant service configurations 3 2 2 Trigger It is invoked when a client application wants to subscribe to the Semantic Pub Sub system and show its interest in the form of query reference to a part of the ontology to describe available services 3 2 3 Preconditions Client applications generally interested or dependent on a portion of the complete sensor network ontology 3 2 4 Postconditions A query request is sent to AE to retrieve configuration data from registry 3 2 5 Stimulus Response Sequences 1 Client applications request for configuration data from registry 2 AE sends query request to the registry to retrieve relevant service configurations 3 2 6 Exceptions If there is no matching service configuration in the registry query outcome returns null 3 2 7 Functional Requirements REQ 1 Malicious queries are detected and rejected REQ 2 The format of the query request is defined 3 3 Retrieval of Service Configuration Initiation On receipt of the query request to retrieve configuration data the AE invokes initialization of Pub Sub operation Figure 5 shows use case for this feature Software Requirements Specification for Semantics based Publish Subscribe System Page 9 Authoritative Entity AE Receive query request lt lt Actor gt gt Service Registry Receive service information K USES List service configurations lt lt Actor gt gt A
23. ork services to changing context notifying client applications of changes and for ensuring effective operations of the Semantic Pub Sub system The use case for this feature is shown in Figure 6 Semantic Pub Sub lt lt Actor gt gt Registry Exchange service m information Notify client application Publish service configurations Update service configuration pu a Subscribe to receive Ontology ien i i Application service configuration representation Figure 1 Operations of Semantic Pub Sub 3 4 1 Actors AE Exchanges service configurations and notify client application Registry Publish service configurations and update them Client application Subscribes to receive service configuration and gets notified of changes 3 4 2 Trigger Once client application subscribes to receive updates to service configurations and get notified during the lifetime of the Semantic Pub Sub system 3 4 3 Preconditions A client application has subscribed to a part of the ontological representation of available Services 3 4 4 Postconditions Necessary functional tasks are carried out and administration for effective operations 3 4 5 Stimulus Response Sequences 1 Once a client application has subscribed to receive notifications on changes to service configuration by expressing interest to a part of the ontology the semantic pub sub operations are initiated Software Requirements Specification for Semantics based Publish Sub
24. s dasa eat aut Nadine ounce dese es acest 5 2l Assumptions and Dependent ieS cranienne a E T A E 6 Do SOV SCCM Eear Sania a 6 3 1 Service Reosttation PUDMSN Jarnesisie siaa SEA O e aiSia 6 3 2 Querying of Service Configuration Subscription sssssssssssssssessrrenrerrrerrrrrerrrrrrrrrrrrerrrrren fi 3 3 Retrieval of Service Configuration Initiation cc cc cccccccssccsecceccceeeeeceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeas 8 3 4 Adaptation to Changes Operational Managementt cc 0ccssessessssssssssssessesssessssessseeeeeeeees 10 3 5 Decommiss on Kc PhaC CMe Nieten akorin Aea e a ean Ne ansei a A e 11 4 External Interface Requirements sesssseecosssseecccssscecccssececocssssecosossscecossssecosssseeecosssssessssssee 12 4 1 User UICC SS pastes a E A ER 12 4 2 Hardware Merl ace Seen E NN 12 4 3 SONWAre MieriaceS ai an A E E 12 4 4 COMMUNIC a EONS MieriaceS sia e a E EE EA 13 5 Other Nonfunctional Requirements sssseeoosssseeoccsssscecocssseecocsssecoccosseecocssssecossssseeossssseesssse 13 5 1 Perlormance Reguireine ILS tac ace heck asc ee ta nace adie awe nian ae tae an ad iaen eee aeato ete 13 5 2 Software Quality PACU LSS earair aS E E EAE EAEE E E S 13 Gy Roleros oetoesan E EAA E a EE E aE EA 13 Revision History Reason For Changes Mukaddim Pathan 20 02 2011 Initial Draft Software Requirements Specification for Semantics based Publish Subscribe System Page 1 1 Introduction 1 1 Purpose T
25. scribe System Page 11 2 Registry publishes available sensor services and updates them according to an ontological representation 3 Query request from client application to retrieve the initial configuration data is directed to AE 4 AE exchanges service information with the registry and notify client applications of ongoing changes 5 AE assists in the administration and enforcement of the functional tasks 3 4 6 Exceptions If there is no client application interested in receiving notification of changes in the service configurations the Semantic Pub Sub system ceases operations 3 4 7 Functional Requirements REQ 1 Semantic Pub Sub is operational REQ 2 Service configurations are published REQ 3 Malicious query requests are identified and acted upon REQ 4 Functional tasks are identified and carried out 3 5 Decommission Replacement There could be circumstances under which the Semantic Pub Sub system ceases its operation This feature 1s associated with the use case shown in Figure 7 3 5 1 Actors AE Governs the system operations 3 5 2 Trigger Termination condition holds 3 5 3 Preconditions There is a functional Semantic Pub Sub system 3 5 4 Postconditions The Semantic Pub Sub system is decommissioned 3 5 5 Stimulus Response Sequences 1 The Semantic Pub Sub system is currently in operation and client applications are notified of changes to service configurations that are of interest to them 2 If ther
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