Abstract — 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 pre-defined 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 logical formalisms for the 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 and examples from common industry use cases to demonstrate the expressiveness of the language and the scalability of the approach.

Abstract. Management, execution and maintenance of Service Level Agreements (SLAs) in the upcoming service oriented IT landscape need new levels of flexibility and automation not available with the current technology. In this paper we evolve a rule based approach to SLA representation and management which allows a clean separation of concerns, i.e. the contractual business logic are separated from the application logic. We make use of sophisticated, logic based knowledge representation (KR) concepts and combine adequate logical formalisms in one expressive logic based framework called ContractLog. ContractLog underpins a declarative rule based SLA (RBSLA) language with which to describe SLAs in a generic way as machine readable and executable contract specifications. Based on ContractLog and the RBSLA we have implemented a high level architecture for the automation of electronic contracts- a rule-based Service Level Management tool (RBSLM) capable of maintaining, monitoring and managing large amounts of complex contract rules. 1 Why declarative rule-based SLA representation? Our studies of a vast number of SLAs currently used throughout the industry have revealed that today’s prevailing contracts are plain natural language documents. Consequently,

Abstract. In this paper we evolve a rule based approach to SLA representation and management which allows separating the contractual business logic from the application logic and enables automated execution and monitoring of SLA specifications. We make use of a set of knowledge representation (KR) concepts and combine adequate logical formalisms in one expressive formal framework called ContractLog. 1

Abstract. Rule-based policy and contract systems have rarely been studied in terms of their software engineering properties. This is a serious omission, because in rule-based policy or contract representation languages rules are being used as a declarative programming language to formalize realworld decision logic and create IS production systems upon. This paper adopts a successful SE methodology, namely test driven development, and discusses how it can be adapted to verification, validation and integrity testing (V&V&I) of policy and contract specifications. Since, the test-driven approach focuses on the behavioral aspects and the drawn conclusions instead of the structure of the rule base and the causes of faults, it is independent of the complexity of the rules and the system under test and thus much easier to use and understand for the rule engineer and the user.

Abstract. Effective SLAs are extremely important to assure business continuity, customer satisfaction and trust. The metrics used to measure and manage performance compliance to SLA commitments are the heart of a successful agreement and are a critical long term success factor. Lack of experience in the use and automation of performance metrics causes problems for many organizations as they attempt to formulate their SLA strategies and set the metrics needed to support those strategies. This paper contributes to a systematic categorization of SLA contents with a particular focus on SLA metrics. The intended goal is to support the design and implementation of automatable SLAs based on efficient metrics for automated monitoring and reporting. The categorization facilitates design decisions, analysis of existing SLAs and helps to identify responsibilities for critical IT processes in disruption management during the execution of SLAs. 1

Abstract. Due to the raising level of abstraction in information systems development many activities of this process are migrating to its early phases. The same is true for testing – modern CASE tools are undertaking validation of software models. In this paper the methodology for checking of conceptual models is proposed as the step-wise process during which model elements including integrity constraints are progressively checked for their adequacy to values of objects, their relationships and constraints of the corresponding problem domain. The checking process is associated with the particular methodology for development of ordered and precise conceptual models (OPCM), which brings improvements to their quality: conformity to normal forms and ontological foundations, and to the observed reality. The rules for checking of integrity constraints are proposed on the base of taxonomy created in the result of analysis of the most promising methods for conceptual modelling.

Event-driven reactive functionalities are an urgent need in nowadays distributed service-oriented applications and (Semantic) Web-based environments. An important problem to be addressed is how to correctly and efficiently capture and process the event-based behavioral, reactive logic represented as ECA rules in combination with other conditional decision logic which is represented as derivation rules. In this paper we elaborate on a homogeneous integration approach which combines derivation rules, reaction rules (ECA rules) and other rule types such as integrity constraint into the general framework of logic programming. The developed ECA-LP language provides expressive features such as ID-based updates with support for external and self-updates of the intensional and extensional knowledge, transactions including integrity testing and an event algebra to define and process complex events and actions based on a novel interval-based Event Calculus variant. 1.

Policy-based systems consist of interacting software artifacts and, at first glance, can be tested as any other software system. In a policy-based system, however, the behavior of system entities may change dynamically and frequently, depending on the policy rules governing this behavior. Therefore, policy-based systems demand for a testing approach that especially allows for the testing of dynamically changing system behavior. Thus, testing of policy rules has to check if the behavior that is actually enforced by a set of policies, conforms to the intended behavior of the corresponding system entities. Scenarios are an important means to specify behavior of software entities. In this paper, we introduce an approach to test policybased systems with scenarios, and present an (embedded) domain-specific language for scenario-based testing. KEY WORDS Policy-based systems, scenario-based testing 1