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General dependability definition:
The dependability of a system is its ability to deliver
specified services to the end users sothat they can justifiably
rely on and trust the services provided by the system.
Dependability has several attributes, including reliability,
availability, maintainability,
confidentiality, integrity, and safety.
- Availability. The availability of a system for a period (0,t)
is the probability that
the system is available for use at any random time in (0,t).-
eliability. The reliability of a system for a period (0,t) is the
probability that the
system is continuously operational (i.e., does not fail) in time
interval (0,t) given
that it is operational at time 0.
- !aintainability" The maintainability of a system is a measure
of the ability of thesystem to undergo maintenance or to return to
normal operation after a failure.
- #onfidentiality" The confidentiality of a system is a measure
of the degree to
$hich the system can ensure that an unauthori%ed user $ill not
be able to
understand protected information in the system.- &ntegrity
and Trust$orthiness. The integrity of a system is the probability
that
errors or attac's $ill not lead to damages to the state of the
system, includingdata, code, etc.
- afety. The safety of a system for a period (0,t) is the
probability that the system
$ill not incur any catastrophic failures in time interval
(0,t).
Dependability research for net-centric applications includes
methods for assuring and
methods for uantitatively assessing each of the dependability
attributes of the system.
Dependability Requirement Engineeringeuirement specification and
analysis of dependability aspects of net$or'
centricapplications.
- Dependability reuirements elicitation
- *ormal and informal methods for the specification of system
dependabilityaspects
- euirement analysis focusing on
o Determination of overall system dependability reuirements as
$ell as
dependability reuirements of various system entities
o Assessment of feasibility, consistency and the cost of
achieving specified
levels of dependability
- Tool support for dependability reuirement specification and
analysis
Dependability Design
Architecture, design and techniues of dependability aspects of
net$or' centricapplications that may dynamically evolve
- Aspect-oriented design for separating out consideration of
dependability aspects
from functional and other non-functional aspects of a given
net-centric application
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- Architectural styles and design patterns for achieving
specific dependability
objectives, e.g., high reliability and+or safety
- Determination of component-+subsystem-level dependability
reuirements formeeting specified dependability objectives for a
given architecture
- Design and development of generic and domain-specific
dependability
assurance+assessment algorithms and techniues
Dependability System Integration and Synthesis
!ethods for selecting and integrating components into systems or
semi-automated orautomated synthesis of the systems that achieve
desired dependability
- !ethods for achieving dependability in integrated systems by
achieving
dependability in individual subsystems
- !ethods for collaborative composition of a set of net-centric
components orservices to build an application to ensure
satisfaction of dependability
reuirements and resolution of conflicting dependability goals
$ithin and across
domains
- ynthesis for system dependability aspects (automatic
transformation of a systemto satisfy dependability reuirements)
Dependability Verification and Validation
#ollaborative verification, validation, and uantitative
assessment of dependability of
dynamically evolving net-centric application systems
- Dependability assessment metrics in net-centric settings-
*ormal methods for verification of the satisfaction of
dependability reuirements
of the system in all phases of the system development
process
- Testing methods for efficient and effective testing of
large-scale net-centric
application systems, including testing techniues for different
entities in the
system and the overall system- #ompositional system
dependability assessment approaches
- Techniues for pin-pointing problem entities
Dependability Run Time Monitoring and daptation
un time modeling, measurement and analysis of the dependability
aspects andadapting to satisfy evolving dependability
reuirements
- Techniues for run time modeling, measurement, and analysis
- Distributed monitoring and efficient assembly of individual
assessment results to
estimate the overall system healthiness and vulnerability-
Techniues and middle$are for dynamic reconfiguration, adaptation,
or s$apping
of system components to achieve evolving dependability
reuirements
