Smart Home Technologies

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Smart Home Technologies

• System Engineering

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System Engineering in Intelligent Environments

• Intelligent Environments are complex systems
  consisting of various components
• Building infrastructure
• Sensor and actuator hardware
• Database system
• Prediction and decision making
• Interaction with inhabitants
• Design and construction of such systems requires
  a systematic approach
• Precise specifications are important
• System has to be treated as a whole

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The Goals of System Engineering

• Increase the probability of success
• Assure that the design addresses the actual
  problems
• Ensure that the desired design is technologically
  possible
• Reduce risk
• Assess the potential risks
• Refine design to address risks
• Reduce total-life-cycle cost
• Reduce the likelihood of large-scale redesign

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System Engineering

• System engineering addresses the complete system
  as a whole
• Put software into context
• Relate software to hardware
• Address work flow and other human activities
• Business model
• Business Process Engineering
• Focus on a business enterprise
• Product Engineering
• Focus on a product to be built

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System Elements

• Systems generally consist of a large number of
  elements and processes that combine in various
  ways to address a given problem
• Software
• Hardware
• People
• Database
• Documentation
• Procedures

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The System Life Cycle
Define Requirements
Retirement, Disposal Replacement
Investigate Alternatives
Operation, Maintenance Evaluation
Full-Scale Design
Integration Test
Implementation
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The System Design Process
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The vee Life-Cycle Model
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System Engineering

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

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Systems Engineering Process
Requirements
Management Element
Plan and Organize
Plans and Direction
Control
Analyze Problem
Assess and Select
Synthesize Solution
Outcomes and Decisions
Verify Solution
Technical Element
Physical Solutions
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Systems Engineering Process

• Many steps are involved in systems engineering
• Requirements engineering
• System modeling
• Risk analysis
• System integration
• Steps are not serial but rather parallel and
  highly iterative

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Requirements Engineering

• Requirements engineering attempts to specify a
  system that meets the customers needs and
  expectations.
• Requirements elicitation
• Requirements analysis
• Specification
• Modeling
• Validation
• Management

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Requirements Discovery

• System requirements have to be determined in
  collaboration with the customer
• Preferences
• Low energy consumption
• Automatic taping of favorite TV shows
• Mandatory requirements
• Maintain temperature
• Prevent intrusion

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Requirements Elicitation

• Eliciting requirements from customers is an
  important and difficult process that poses many
  challenges
• Scope
• Defining the system boundary
• Lack of clarity on overall objectives
• Understanding
• Customer not skilled
• Doesnt state the obvious
• Requirements ambiguous, conflicting,
• Volatility
• Requirements change over time

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Requirements Elicitation

• Requirements elicitation process
• Assess feasibility
• Identify people and their roles
• Define technical environment
• Identify domain constraints
• Select elicitation methods
• Solicit participation from several perspectives
• Identify ambiguous requirements
• Create usage scenarios

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Requirements Specification

• Requirements specifications have to be formalized
  so that they can be used in the design and
  construction process
• Elements of a Specification
• Written documents
• Graphical models
• Formal mathematical models
• Final work product
• System Specification

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Requirements Validation

• To 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?

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System Modeling

• Once requirements are specified, systems
  engineering aims at forming a system model at
  various resolutions
• At each resolution
• Define processes
• Represent process behavior
• List process assumptions
• Define external and internal inputs
• Model linkages (control, data, I/O)

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System Modeling

• System modeling identifies and defines the main
  aspects and specifications of the system
• Assumptions
• range of allowable data
• Simplifications
• partition data into categories
• Limitations
• bounds on functionality
• Constraints
• guide the implementation
• Preferences
• indicate preferred architecture (data, functions,
  technology)

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System Modeling

• Part of the role of system modeling is to
  translate the requirements specifications into a
  possible design and to identify potential
  problems
• Evaluate the systems components in relation to
  one another
• Link requirements to system components
• Validate assumptions about data flow, work flow,
  input / output, ...

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Risk Management

• Risk assessment and management identifies and
  assesses different risks in the development
  process and of the product
• Product risk
• Product performance
• Reliability of home access
• Consistency of AC system
• Cost of door authentication system
• Project risk
• Cost, schedule and process performance
• Duration of the technology development
• Cost of production
• Safety and environmental risk
• Risks to the public
• Reliability of outdoor robots

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Risk Management

• Risk management in industrial practice is a
  tradeoff between costs and risks
• Good 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

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System Engineering in Risk-Prone Environments

• At 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.

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Construction And Integration

• The construction phase attempts to take the
  models and specifications and translate them into
  a product
• Construction focuses on the details
• Implementation of individual elements
• Goals
• Implement the architectures and infrastructure
• Integrate and deploy the completed system

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Requirements Management

• Assurance of conformity of models and constructed
  products with the requirements is an important
  part of system engineering
• Active throughout the life-cycle
• Identify, control, and track
• New requirements
• Changes to requirements
• Tools
• Traceability Table
• Relates requirements to features, source,
  dependency, subsystem, interface, etc.

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System Engineering Tasks
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Conclusions

• System engineering is important for the
  successful construction of large scale systems
• Assure requirements are specified correctly
• Engineers and scientists do not necessarily know
  what inhabitants of intelligent environments
  really need
• Model the system to assess feasibility
• Often intended features are not feasible or too
  costly
• The self-regulating home is not (yet)
  technologically possible
• Assess economic viability
• To make intelligent environments reality they
  have to be economical and fit the requirements of
  users
• Assess project risks and track requirements
• Economic as well as physical risks to inhabitants
  have to be taken into account to field a system
• A good engineer in intelligent environments has
  to have some understanding of all aspects of
  system engineering