Smart Home Technologies System Engineering. System Engineering in Intelligent Environments Intelligent Environments are complex systems consisting of

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  • Smart Home TechnologiesSystem Engineering

  • System Engineering in Intelligent EnvironmentsIntelligent Environments are complex systems consisting of various componentsBuilding infrastructureSensor and actuator hardwareDatabase systemPrediction and decision makingInteraction with inhabitantsDesign and construction of such systems requires a systematic approachPrecise specifications are importantSystem has to be treated as a whole

  • The Goals of System EngineeringIncrease the probability of successAssure that the design addresses the actual problemsEnsure that the desired design is technologically possibleReduce riskAssess the potential risksRefine design to address risksReduce total-life-cycle costReduce the likelihood of large-scale redesign

  • System EngineeringSystem engineering addresses the complete system as a wholePut software into contextRelate software to hardwareAddress work flow and other human activitiesBusiness modelBusiness Process EngineeringFocus on a business enterpriseProduct EngineeringFocus on a product to be built

  • System ElementsSystems generally consist of a large number of elements and processes that combine in various ways to address a given problemSoftwareHardwarePeopleDatabaseDocumentationProcedures

  • DefineRequirementsInvestigateAlternativesFull-ScaleDesignImplementationIntegration & TestOperation, Maintenance& EvaluationRetirement,Disposal &ReplacementThe System Life Cycle

  • The System Design Process

  • The vee Life-Cycle Model

    text

    MissionAnalysis

    SystemRequirements

    FunctionalDecomposition

    PhysicalDecomposition

    Operation &Retirement

    FinalSystem Test

    VerifySubsystems

    TestComponents

    BuildComponents

    Test Plan

    Verification Plan

    Validation Plan

    Continuous Quality Improvement Plan

    Decomposition

    Integration

    The design downstroke and the manufacturing upstroke

  • System EngineeringSystem engineering is aimed at managing the system life cycle throughout the specification, design, and construction phasesIn a business this has to involve management, engineering, and human factors concernsRequires understanding of all the components that make up a system

  • Management ElementPlan andOrganizeControlTechnical ElementAnalyzeProblemSynthesizeSolutionVerify SolutionAssess and SelectPlans and DirectionOutcomes and DecisionsRequirementsPhysical SolutionsSystems Engineering Process

  • Systems Engineering ProcessMany steps are involved in systems engineeringRequirements engineeringSystem modelingRisk analysisSystem integration Steps are not serial but rather parallel and highly iterative

  • Requirements EngineeringRequirements engineering attempts to specify a system that meets the customers needs and expectations.Requirements elicitationRequirements analysis SpecificationModelingValidationManagement

  • Requirements DiscoverySystem requirements have to be determined in collaboration with the customerPreferencesLow energy consumptionAutomatic taping of favorite TV showsMandatory requirementsMaintain temperature Prevent intrusion

    Box sizes with text.Hit to start anew line of text.

    text

    WriteSystem Requirements

    RewriteRequirements

    No

    Ask Why EachRequirementIs Needed

    Customer Concurs?

    RewriteRequirements

    ValidatedRequirements

    DefineFiguresof Merit

    Validatethe Set ofRequirements

    Valid?

    Yes

    ProblemStatement

    No

  • Requirements ElicitationEliciting requirements from customers is an important and difficult process that poses many challenges Scope:Defining the system boundaryLack of clarity on overall objectivesUnderstanding: Customer not skilledDoesnt state the obviousRequirements ambiguous, conflicting, Volatility:Requirements change over time

  • Requirements ElicitationRequirements elicitation process:Assess feasibilityIdentify people and their rolesDefine technical environmentIdentify domain constraintsSelect elicitation methodsSolicit participation from several perspectivesIdentify ambiguous requirementsCreate usage scenarios

  • Requirements SpecificationRequirements specifications have to be formalized so that they can be used in the design and construction processElements of a Specification:Written documentsGraphical modelsFormal mathematical modelsFinal work product:System Specification

  • Requirements ValidationTo assure that requirements specifications can be used and will lead to good designs they have to be evaluated Are requirements stated clearly?Are requirements verified by an identified source?Are requirements consistent with overall objective?Are requirements consistent with domain constraints?Are requirements essential to overall objective?Are requirements bounded and unambiguous?Are requirements conflicting with other requirements?Are requirements sufficiently abstract?Are requirements achievable in the technical environment?Are requirements testable, with specified tests?Are requirements traceable to the system model?

  • System ModelingOnce requirements are specified, systems engineering aims at forming a system model at various resolutionsAt each resolution:Define processesRepresent process behavior List process assumptions Define external and internal inputsModel linkages (control, data, I/O)

  • System ModelingSystem modeling identifies and defines the main aspects and specifications of the systemAssumptionsrange of allowable dataSimplificationspartition data into categoriesLimitationsbounds on functionalityConstraintsguide the implementationPreferencesindicate preferred architecture (data, functions, technology)

  • System ModelingPart of the role of system modeling is to translate the requirements specifications into a possible design and to identify potential problemsEvaluate the systems components in relation to one anotherLink requirements to system componentsValidate assumptions about data flow, work flow, input / output, ...

  • Risk ManagementRisk assessment and management identifies and assesses different risks in the development process and of the productProduct riskProduct performanceReliability of home accessConsistency of AC systemCost of door authentication systemProject riskCost, schedule and process performanceDuration of the technology development Cost of productionSafety and environmental riskRisks to the publicReliability of outdoor robots

  • Risk ManagementRisk management in industrial practice is a tradeoff between costs and risksGood risk management will not prevent bad things from happening. But when bad things happen, good risk management will have anticipated them and will reduce their negative effects

  • System Engineering in Risk-Prone EnvironmentsAt NASA, the probability of mission failure was about 10-2, but the severity was near 1. The product of these numbers was big, so they did lots of systems engineering.At a big software house, the probability that a new system will destroy user files was about 1, but their perceived severity was around 10-6. They did not care if J.Q. Public lost a few files. Therefore, they did little systems engineering.

  • Construction And IntegrationThe construction phase attempts to take the models and specifications and translate them into a productConstruction focuses on the detailsImplementation of individual elementsGoals:Implement the architectures and infrastructureIntegrate and deploy the completed system

  • Requirements ManagementAssurance of conformity of models and constructed products with the requirements is an important part of system engineering Active throughout the life-cycleIdentify, control, and track:New requirementsChanges to requirementsTools:Traceability TableRelates requirements to features, source, dependency, subsystem, interface, etc.

  • System Engineering Tasks

    State the problem

    Design the system

    Produce documentation

    Understand customer needs

    Sensitivity analyses

    Lead teams

    Discover requirements

    Assess & manage risk

    Assess performance

    Validate requirements

    Reliability analyses

    Prescribe tests

    Investigate alternatives

    Integrate system components

    Conduct reviews

    Define quantitative measures

    Design & manage interfaces

    Verify requirements

    Model the system

    Execute configuration management

    Perform total system test

    Functional decomposition

    Project management

    Re-evaluate & Improve quality

  • ConclusionsSystem engineering is important for the successful construction of large scale systemsAssure requirements are specified correctlyEngineers and scientists do not necessarily know what inhabitants of intelligent environments really needModel the system to assess feasibilityOften intended features are not feasible or too costlyThe self-regulating home is not (yet) technologically possibleAssess economic viabilityTo make intelligent environments reality they have to be economical and fit the requirements of usersAssess project risks and track requirementsEconomic as well as physical risks to inhabitants have to be taken into account to field a systemA good engineer in intelligent environments has to have some understanding of all aspects of system engineering