Concept of DEOS

In order to achieve Open Systems Dependability, we have proposed the concepts of the following three_items;

    1. DEOS Process
    2. DEOS Architecture
    3. D-Case

Below, each is explained.

1. DEOS Process

  • An iterative process, which consists of the followings is indispensable.
     - A cycle to adapt the system according to changes in objectives and environment
     - A cycle to take immediate actions and fix failures when they occur
  • The process, which consists of these two cycles, is a Process of Processes
    composed of component processes and states
     - These processes are organically united.

We named this integrated iterative process "DEOS Process".

DEOS Process DEOS Process

2. DEOS Architecture

In order to apply the DEOS process to systems, an architecture that can effectively support the DEOS process is required. We think that key components of this DEOS architecture include; 1) A set of tools to support the requirements elicitation/risk analysis phase, and database to store agreement and the process to reach agreement, 2) A set of tools for program verification, benchmarking, and fault injection test, and 3) A runtime environment to monitor the system all the time, to record and report events, and to react dynamically to minimize the damage to the services when failure occurs. We named the architecture as "DEOS Architecture".

DEOS Architecture DEOS Architecture

3. D-Case

The largest benefits to be gained by using the "DEOS Process" are that sufficient agreement can be carried out leading to agreement after the stakeholders have change their demands and that reasoning / argument that reached the agreed-upon results / conclusion.can be recorded. We named this consensus building method "D-Case", and also call the agreement document produced based on the agreement descriptions "D-Case".

By clearly and completely describing the following four points, "D-Case" offers the framework for building a more firmly based argument.

  • Claim
  • Argumentation
  • Evidence
  • Explicit Assumption

D-Case D-Case

"D-Case" is an important means enabling action to be taken that is suitable at the time an obstacle arises, and is a in the "DEOS architecture." Moreover, "D-Case" supports cause investigation of the obstacle and achievement of complete of accountability.

Sample Movie : The system which "DEOS Architecture" cooperates with "D-Case" ( 12.5MB 2min27sec )

Note: Voice narration can be heard.

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