1 A Context Analysis Method for Constructing Reliable Embedded Systems Naoyasu Ubayashi, Toshiki Seto, Hirotoshi Kanagawa, Susumu Taniguchi, and Jun Yoshida (Kyushu Institute of Technology) Takeshi Sumi and Masayuki Hirayama (Toshiba) May 11, 2007 MISE 200 8
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A Context Analysis Method for Constructing Reliable Embedded Systems
MISE 200 8. A Context Analysis Method for Constructing Reliable Embedded Systems. Naoyasu Ubayashi , Toshiki Seto , Hirotoshi Kanagawa, Susumu Taniguchi, and Jun Yoshida (Kyushu Institute of Technology) Takeshi Sumi and Masayuki Hirayama (Toshiba) May 11, 2007. - PowerPoint PPT Presentation
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A Context Analysis Methodfor Constructing Reliable Embedded Systems
Naoyasu Ubayashi, Toshiki Seto, Hirotoshi Kanagawa,Susumu Taniguchi, and Jun Yoshida (Kyushu Institute of Technology)Takeshi Sumi and Masayuki Hirayama (Toshiba)
May 11, 2007
MISE 200 8
Contexts in embedded systems
Many embedded systems not only affect their contexts through actuators but also are affected by their contexts through sensors.
However, requirements analysis is mainly conducted from the viewpoint of system functions, and contexts are only roughly analyzed.
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Unexpected behavior might emerge in a system if a developer does not recognize any possible conflicting combinations between the system and contexts.
It is difficult to decide the boundary of contexts that should be taken into account: which contexts should be included as the targets of requirements analysis.
EmbeddedSystem
Actuator
SensorContexts
Boundary ?Association ?Frame
Problem !
Today’s my talk
We propose a context-dependent requirements analysis method called CAMEmb (Context Analysis Method for Embedded systems).
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UML Profile for Context Analysis
Formal Methods( VDM++ )
CAMEmb is a systematic approach to
exploring context boundary avoiding the frame problem,
verifying whether requirements can be satisfied under the expected contexts,
changing requirements or context boundary if not satisfied.
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Outline
1. Motivation2. CAMEmb3. MDD based on CAMEmb4. Conclusions and Future work
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1. Motivation
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Example: an electric pot
water level sensor
heater
thermostat liquid
context
system
pot
The pot controls the water temperature by turning on or off the heater.
The pot changes its mode to the heat-retaining mode when the temperature becomes 100 Celsius.
The pot observes the volume from the water level.
Boil: () ==> ()Boil() == while thermostat.GetTemperature() < 100.0 do heater.On();
However, faults may occur if the expected contexts are changed.
---for example, the circumstance of the low air pressure
Should air pressure be taken into account ?
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water level sensor
heater
thermostat Liquid
context
system
pot
Non trivial !Air
PressureAir
Pressure
Boundary
? ?This depends on user requirements.
However, it is important to check the consistency if we decide that air pressure must be taken into account.
It is also important to check the impact when air pressure is included in the expected contexts.
Problems to be tackled
The boundary of contexts should be determined from user requirements.
We must take into account the influence that occurs in the cooperation among a target system and contexts within the boundary.
We must also detect defects by recognizing any possible conflicting combinations among the system and contexts.
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Systematic way forcontext analysis
2. CAMEmb
Context Analysis Methodfor Embedded systems
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CAMEmb Overview
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Formal Methods( VDM++ )
UML Profile for Context Analysis
Context modeling
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UML profile for context analysis Steps forexploring boundary
1. Context elements (value object) observed or controlled directly by a sensor or an actuator are extracted.
2. Impact factors that affect the states (values) of these context elements are extracted using guide words.Initial