Jari Koistinen

Bio: Jari Koistinen is an academic researcher from Hewlett-Packard. The author has contributed to research in topics: Specification language & Quality of service. The author has an hindex of 6, co-authored 7 publications receiving 643 citations. Previous affiliations of Jari Koistinen include Swedish Institute of Computer Science.

Quality of services specification in distributed object systems design

Abstract: Traditional object-oriented design methods deal with the functional aspects of systems, but they do not address quality of service (QoS) aspects such as reliability, availability, performance, security, and timing. However, deciding which QoS properties should be provided by individual system components is an important part of the design process. Different decisions are likely to result in different component implementations and system structures. Thus, decisions about component-level QoS should be made at design time, before the implementation is begun. Since these decisions are an important part of the design process, they should be captured as part of the design. We propose a general Quality-of-Service specification language, which we call QML. In this paper we show how QML can be used to capture QoS properties as part of designs. In addition, we extend UML, the de-facto standard object-oriented modeling language, to support the concepts of QML. QML is designed to integrate with object-oriented features, such as interfaces, classes, and inheritance. In particular, it allows specification of QoS properties through refinement of existing QoS specifications. Although we exemplify the use of QML to specify QoS properties within the categories of reliability and performance, QML can be used for specification within any QoS category-QoS categories are user-defined types in QML.

Quality-of-service specification in distributed object systems

Abstract: Traditional object-oriented design methods deal with the functional aspects of systems, but they do not address quality-of-service (QoS) aspects, such as reliability, availability, performance, security and timing. However, deciding which QoS properties should be provided by individual system components is an important part of the design process. Different decisions are likely to result in different component implementations and system structures. Thus, decisions about component-level QoS should commonly be made at design time, before the implementation is begun. Since these decisions are an important part of the design process, they should be captured as part of the design. We propose a general quality-of-service specification language, which we call QML. In this paper we show how QML can be used to capture QoS properties as part of designs. In addition, we extend UML, the de facto standard object-oriented modelling language, to support the concepts of QML. QML is designed to integrate with object-oriented features, such as interfaces, classes and inheritance. In particular, it allows specification of QoS properties through refinement of existing QoS specifications. Although we exemplify the use of QML to specify QoS properties within the categories of reliability and performance, QML can be used for specification within any QoS category - QoS categories are user-defined types in QML. Sometimes, QoS characteristics and requirements change dynamically due to changing user preferences, or changes in the environment. For such situations static specification is insufficient. To allow for dynamic systems that change and evolve over time, we provide a QoS specification runtime representation. This representation enables systems to create, manipulate and exchange QoS information, and thereby negotiate and adapt to changing QoS requirements and conditions.

Utility-based multi-category quality-of-service negotiation in distributed systems

Abstract: In a distributed system, a method and system for negotiating a multi-category Quality-of-Service (QoS) agreement between a client and a server includes a client agent enabled to calculate an expected utility to a client of multiple multi-category QoS specifications. The client agent obtains the QoS specifications by transmitting a QoS specification request to a server agent or a broker. The expected utility calculation, based on a probabilistic estimate of QoS levels included in the QoS specifications, enables the client agent to distinguish the QoS specifications of greater value from those of lesser value. The client agent selects at least one of the QoS specifications to be included into an offer for a QoS agreement based on the expected utility calculation. In a preferred embodiment, the client agent selects the QoS specifications determined to be most valuable to the client. The offer is transmitted to the server agent to request a service provided by a server at QoS levels represented by the selected QoS specifications. After transmitting the offer, the client monitors a connection to the server agent for either an acceptance, a rejection, or a counteroffer to the offer. Communication between the client agent and the server agent conforms to a negotiation protocol which provides a set of rules for transmission of negotiation messages.

Quality of service aware distributed object systems

Abstract: Computing systems deliver their functionality at a certain level of performance, reliability, and security. We refer to such non-functional aspects as quality-of-service (QoS) aspects. Delivering a satisfactory level of QoS is very challenging for systems that operate in open, resource varying environments such as the Internet or corporate intranets. A system that operates in an open environment may rely on services that are deployed under the control of a different organization, and it cannot per se make assumptions about the QoS delivered by such services. Furthermore, since resources vary, a system cannot be built to operate with a fixed level of available resources. To deliver satisfactory QoS in the context of external services and varying resources, a system must be QoS aware so that it can communicate its QoS expectations to those external services, monitor actual QoS based on currently available resources, and adapt to changes in available resources. A QoS-aware system knows which level of QoS it needs from other services and which level of QoS it can provide. To build QoS-aware systems, we need a way to express QoS requirements and properties, and we need a way to communicate such expressions. In a realistic system, such expressions can become rather complex. For example, they typically contain constraints over user-defined domains where constraint satisfaction is determined relative to a user-defined ordering on the domain elements. To cope with this complexity we are developing a specification language and accompanying runtime representation for QoS expressions. This paper introduces our language but focuses on the runtime representation of QoS expressions. We show how to dynamically create new expressions at runtime and how to use comparison of expressions as a foundation for building higher-level QoS components such as QoS-based traders.

Dimensions for Reliability Contracts in Distributed Object Systems

Abstract: Designing and managing distributed systems with predictable reliability and availability is generally difficult. Whenever components are specified, used, and managed it is often unclear what reliability requirements different components are expected to satisfy. The problem of specifying and satisfying reliability requirements needs to be addressed for many different situations and contexts. We need languages and tools that allow design time and run time specification of reliability requirements and offerings. We need quality of service (QoS) contracts that can be negotiated and monitored dynamically. From a management view, we need the ability to define reliability contracts between system components so that they can be effectively managed and charged for in heterogeneous and federated systems. Common to all these situations is the need for a vocabulary for the specification of reliability characteristics. Such a vocabulary should be complete in the sense that it captures the important aspects of service reliability without getting too complicated. In addition, it should be independent of any implementation techniques and mechanisms. This paper proposes such a vocabulary as a set of dimensions that can be used to characterize the reliability of distributed services. The dimensions are focused on distributed object systems but can easily be abstracted to cover other architectures for distributed systems.

A model for web services discovery with QoS

Abstract: Web services technology has generated a lot interest, but its adoption rate has been slow. This paper discusses issues related to this slow take up and argues that quality of services is one of the contributing factors. The paper proposes a new Web services discovery model in which the functional and non-functional requirements (i.e. quality of services) are taken into account for the service discovery. The proposed model should give Web services consumers some confidence about the quality of service of the discovered Web services.

Modeling Quality of Service for Workflows and Web Service Processes

Abstract: Workflow management systems (WfMSs) have been used to support various types of business processes for more than a decade now. In workflows for e-commerce and Web service applications, suppliers and customers define a binding agreement or contract between the two parties, specifying Quality of Service (QoS) items such as products or services to be delivered, deadlines, quality of products, and cost of services. The management of QoS metrics directly impacts the success of organizations participating in e-commerce. Therefore, when services or products are created or managed using workflows, the underlying workflow system must accept the specifications and be able to estimate, monitor, and control the QoS rendered to customers. In this paper, we present a predictive QoS model that makes it possible to compute the quality of service for workflows automatically based on atomic task QoS attributes. To this end, we present a model that specifies QoS and describe an algorithm and a simulation system in order to compute, analyze and monitor workflow QoS metrics.

System and method to provide routing control of information over networks

Abstract: A system and method for controlling routing of data. It is determined whether at least one data flow is active, the at least one data flow having an ingress portion of a current ingress path to a first point from a second point and an egress portion of a current egress path to the second point from the first point. Another data flow is routed via a next ingress portion of a next path to the first point from the second point.

Interval Neutrosophic Sets and Logic: Theory and Applications in Computing

Abstract: A neutrosophic set is a part of neutrosophy that studies the origin, nature, and scope of neutralities, as well as their interactions with different ideational spectra. The neutrosophic set is a powerful general formal framework that has been recently proposed. However, the neutrosophic set needs to be specified from a technical point of view. Here, we define the set-theoretic operators on an instance of a neutrosophic set, and call it an Interval Neutrosophic Set (INS). We prove various properties of INS, which are connected to operations and relations over INS. We also introduce a new logic system based on interval neutrosophic sets. We study the interval neutrosophic propositional calculus and interval neutrosophic predicate calculus. We also create a neutrosophic logic inference system based on interval neutrosophic logic. Under the framework of the interval neutrosophic set, we propose a data model based on the special case of the interval neutrosophic sets called Neutrosophic Data Model. This data model is the extension of fuzzy data model and paraconsistent data model. We generalize the set-theoretic operators and relation-theoretic operators of fuzzy relations and paraconsistent relations to neutrosophic relations. We propose the generalized SQL query constructs and tuple-relational calculus for Neutrosophic Data Model. We also design an architecture of Semantic Web Services agent based on the interval neutrosophic logic and do the simulation study.