1,415 research outputs found
Knowledge Representation Concepts for Automated SLA Management
Outsourcing of complex IT infrastructure to IT service providers has
increased substantially during the past years. IT service providers must be
able to fulfil their service-quality commitments based upon predefined Service
Level Agreements (SLAs) with the service customer. They need to manage, execute
and maintain thousands of SLAs for different customers and different types of
services, which needs new levels of flexibility and automation not available
with the current technology. The complexity of contractual logic in SLAs
requires new forms of knowledge representation to automatically draw inferences
and execute contractual agreements. A logic-based approach provides several
advantages including automated rule chaining allowing for compact knowledge
representation as well as flexibility to adapt to rapidly changing business
requirements. We suggest adequate logical formalisms for representation and
enforcement of SLA rules and describe a proof-of-concept implementation. The
article describes selected formalisms of the ContractLog KR and their adequacy
for automated SLA management and presents results of experiments to demonstrate
flexibility and scalability of the approach.Comment: Paschke, A. and Bichler, M.: Knowledge Representation Concepts for
Automated SLA Management, Int. Journal of Decision Support Systems (DSS),
submitted 19th March 200
Designing Normative Theories for Ethical and Legal Reasoning: LogiKEy Framework, Methodology, and Tool Support
A framework and methodology---termed LogiKEy---for the design and engineering
of ethical reasoners, normative theories and deontic logics is presented. The
overall motivation is the development of suitable means for the control and
governance of intelligent autonomous systems. LogiKEy's unifying formal
framework is based on semantical embeddings of deontic logics, logic
combinations and ethico-legal domain theories in expressive classic
higher-order logic (HOL). This meta-logical approach enables the provision of
powerful tool support in LogiKEy: off-the-shelf theorem provers and model
finders for HOL are assisting the LogiKEy designer of ethical intelligent
agents to flexibly experiment with underlying logics and their combinations,
with ethico-legal domain theories, and with concrete examples---all at the same
time. Continuous improvements of these off-the-shelf provers, without further
ado, leverage the reasoning performance in LogiKEy. Case studies, in which the
LogiKEy framework and methodology has been applied and tested, give evidence
that HOL's undecidability often does not hinder efficient experimentation.Comment: 50 pages; 10 figure
Executable specication of open multi-agent systems
Multi-agent systems where the agents are developed by parties with competing interests, and where there is no access to an agent's internal state, are often classi ed as `open'. The members of such systems may inadvertently fail to, or even deliberately choose not to, conform to the system speci cation. Consequently, it is necessary to specify the normative relations that may exist between the members, such as permission, obligation, and institutional power. We present a framework being developed for executable speci cation of open multi-agent systems. We adopt a bird's eye view of these systems, as opposed to an agent's perspective whereby it reasons about how it should act. This paper is devoted to the presentation of various examples from the NetBill protocol formalised in terms of institutional power, permission and obligation. We express the system speci cation in the Event Calculus and execute the speci cation by means of a logic programming implementation. We also give several example formalisations of sanctions for dealing with violations of permissions and obligations. We distinguish between an open multi-agent system and the procedure by which an agent enters and leaves the system. We present examples from the speci cation of a role-management protocol for NetBill, and demonstrate the interplay between such a protocol and the corresponding multi-agent system
Formal Verification of Hand-Coded Software Some Industrial Experiments and Lessons Learnt
International audienceThis paper gives an account of an ongoing attempt to prove the safety properties, of a hand-coded safety critical embedded software of industrial size. The method used is based on annotating the C source files with assertions that encode the safety-related functional properties to be satisfied by the software, and then generating proof obligations to be discharged by some theorem provers. We discuss what has been achieved and what difficulties were encountered, from which we derive requirements regarding the evolution of the verification tools involved in that experiment
09121 Abstracts Collection -- Normative Multi-Agent Systems
From 15.03. to 20.03.2009, the Dagstuhl Seminar 09121 ``Normative Multi-Agent Systems \u27\u27 was held in Schloss Dagstuhl~--~Leibniz Center for Informatics.
During the seminar, several participants presented their current
research, and ongoing work and open problems were discussed. Abstracts of
the presentations given during the seminar as well as abstracts of
seminar results and ideas are put together in this paper. The first section
describes the seminar topics and goals in general
Formal and Fault Tolerant Design
Software quality and reliability were verified for a long time at the post-implementation level (test, fault sce-nario ...). The design of embedded systems and digital circuits is more and more complex because of inte-gration density, heterogeneity. Now almost ¾ of the digital circuits contain at least one processor, that is, can execute software code. In other words, co-design is the most usual case and traditional verification by simu-lation is no more practical. Moreover, the increase in integration density comes with a decrease in the reliabil-ity of the components. So fault detection, diagnostics techniques, introspection are essential for defect toler-ance, fault tolerance and self repair of safety-critical systems. The use of a formal specification language is considered as the foundation of a real validation. What we would like to emphasize is that refinement (from an abstract model to the point where the system will be implemented) could be and should be formal too in order to ensure the traceability of requirements, to man-age such development projects and so to design fault-tolerant systems correct by proven construction. Such a thorough approach can be achieved by the automation or semi-automation of the refinement process. We have studied how to ensure the traceability of these requirements in a component-based approach. Re-liability, fault tolerance can be seen here as particular refinement steps. For instance, a given formal specifi-cation of a system/component may be refined by adding redundancy (data, computation, component) and be verified to be fault-tolerant w.r.t. some given fault scenarios. A self-repair component can be defined as the refinement of its original form enhanced with error detection. We describe in this paper the PCSI project (Zero Defect Systems) based on B Method, VHDL and PSL. The three modeling approaches can collaborate together and guarantee the codesign of embedded systems for which the requirements and the fault-tolerant aspects are taken into account for the beginning and formally verified all along the implementation process
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