Sebastian Hudert

Negotiating SLAs - An Approach for a Generic Negotiation Framework for WS-Agreement

The current Web Services Agreement specification draft proposes a simple request-response protocol for agreement creation only addressing bilateral offer exchanges. This paper proposes a framework augmenting this WS-Agreement to enable negotiations according to a variety of bilateral and multilateral negotiation protocols. The framework design is based on a thorough analysis of taxonomies for negotiations from the literature in order to allow for capturing a variety of different negotiation models within a single, WS-Agreement compatible, framework. In order to provide for the intended flexibility, the proposed protocol takes a two-stage approach: a meta-protocol is conducted among interested parties to agree on a common negotiation protocol first before the real negotiation is carried out in the second step due to the protocol established in the first step.

On the Simulation of Grid Market Coordination Approaches

Grid computing has recently become an important paradigm for managing computationally demanding applications, composed of a collection of services. The dynamic discovery of services, and the selection of a particular service instance providing the best value out of the discovered alternatives, poses a complex multi-attribute n:m allocation decision problem, which is often solved using a central resource broker. However, decentralized approaches to this service allocation problem represent a much more flexible alternative, thus promising improvements in the efficiency of the resulting negotiations and service allocations. This paper compares centralized and decentralized service allocation mechanisms in Grid market scenarios according to a defined set of metrics.

On computer simulation as a component in information systems research

Computer simulation is widely regarded as a useful activity during various phases of research However, depending on its context, the meaning, definition, and focus of the term can vary: While in traffic planning, for example, simulation is used to determine useful configurations of a road network and thus focuses on the environment, there is an entirely different perspective of simulations when used within multi-agent systems In such settings, the environment of the agents remains static, while the interesting research questions concern the behavior of the agents themselves The research focuses on the microscopic level and resulting emergent behavior This article addresses the different meanings of simulation and puts them in the context of a research process that treats descriptive and prescriptive research as two sides of the same coin Building on this abstract research process, we develop a framework to classify different types of simulation, based on the actual research activity they are intended to be used for This framework can thus serve subsequently as a guideline on the usage of computer simulation as a research tool.

A Negotiation Protocol Description Language for Automated Service Level Agreement Negotiations

The vision of an open and global Internet of Services (IoS) is driven by globalization and fast changing settings when trading on a world-wide scope. It requires automated on-line techniques for handling services and resources themselves, for advertising and discovery as well as for the on-the-flynegotiation of proper terms for their use. In such a setting covering completely different branches and traditions of business, a flexible infrastructure for negotiating service level agreements is mandatory. In this paper, we propose an extended service usage cycle suitable for IoS along with an expressive but still machine manageable protocol description language capable of specifying a multitude of different negotiation protocols. It supports the extended usage cycle and permits choosing services with appropriate SLA negotiation styles as well as performing SLA negotiations based on the style agreed by potential business partners.

CATNETS - open market approaches for self-organizing grid resource allocation

Grid computing has recently become an important paradigm for managing computationally demanding applications, composed of a collection of services. The dynamic discovery of services, and the selection of a particular service instance providing the best value out of the discovered alternatives, poses a complex multi-attribute n:m allocation decision problem. Decentralized approaches to this service allocation problem represent a flexible alternative to central resource brokers, thus promising improvements in the efficiency of the resulting negotiations and service allocations. This paper analyses the impact of the service density on the profit and market price estimation using a decentralized service allocation mechanism in a grid market scenario.

Towards Reputation Enhanced Electronic Negotiations for Service Oriented Computing

Electronic commerce mechanisms are mainly investigated in two independent research areas: service-oriented computing (SOC) and multi-agent systems. The former as a means to deliver electronic services of various granularity and the latter as a testbed of electronic negotiation mechanisms. However, both research areas heavily rely on each other. On the one hand, service-oriented architectures need to support dynamic cooperation, negotiation, and adaptive interactions between offered services. On the other hand SOC represents a promising application for software agent technologies as a paradigm for electronic negotiations which future service economies will more and more rely on. Apart from the high flexibility and efficiency of such service economies, problems similar to the ones in real world economies will arise, such as the trusting problem between market participants. In this paper, we investigate the efficiency of reputation concepts in different negotiation protocols for electronic service economies. Based on social science findings we deduct hypotheses on the applicability of such mechanisms in various electronic negotiation settings.

Transactional service life cycle management in smart electromobility ecosystems

Smart connected electromobility will leverage the cross-domain cooperation along a new value chain of stakeholders from the automotive and energy industry. Intelligent charge management, i.e. charging the electric vehicle as a tradeoff between charging costs and personal or operational constraints, represents an important service in an electronic service market for electromobility. The market features the energy supplier as a service provider, the electric vehicle as a service consumer along with intermediate brokers in between. All of them continuously interact to exchange data, thus implementing the vision of an open and global Internet of Services in an electromobile ecosystem. A joint service life cycle management which considers both, the build-time and the runtime view of a service, is essential for such a service market. It allows the service provider to design, implement and deploy services while investigating systems of deployed services and their on-demand consumption at run-time. In this paper we present such an integrated service life cycle model for electronic electromobility market places. The life cycle model will be elaborated by means of an intelligent charge management use case.

Global grids - making a case for self-organization in large-scale overlay networks

Grid computing has recently become an important paradigm for managing computationally demanding applications, composed of a collection of services. The dynamic discovery of services, and the selection of a particular service instance providing the best value out of the discovered alternatives, poses a complex multi-attribute n:m allocation decision problem, which is often solved using a centralized resource broker. To manage complexity, this article proposes a two-layered architecture for decentralized service discovery in such Application Layer Networks (ALN). The first layer consists of a service market in which complex services are translated to a set of basic services, which are distinguished by price and availability. The second layer provides an allocation of services to appropriate resources in order to enact the specified services. This framework comprises the foundations for a later comparison of centralized and decentralized market mechanisms for allocation of services and resources in ALNs and Grids in general.

A Proposal for a Life Cycle Model for Electronic Service Markets

Researchers and industry envision the next generation Internet to be a global, socio-technical information infrastructure, where humans as well as software agents continuously interact to trade electronic services, forming a digital economy of its own. For an economically successful participation in the IoS a dedicated management approach for electronic services is needed. In this paper we present a proposal for such a service-centric life cycle model acting as a conceptual basis for (automated) service management at both, build and run time. It is used in a second step to define a comprehensive spiral model of service development and usage for electronic service markets. A real-world business case is finally used to demonstrate the benefits of our approach.

From Service Markets to Service Economies – An infrastructure for protocol-generic SLA negotiations

Visions of 21st century’s information systems show highly specialized digital services and resources, interacting continuously and with a global reach. For a broad adoption of this vision in a commercial context it is crucial to have a mechanism in place to guarantee quality of service and to decentrally coordinate the involved resources. Current service infrastructures try to tackle these problems by applying socioeconomic mechanisms such as electronic negotiations and service level agreements. Such technologies allow for the implementation of electronic service markets in analogy to real-world markets for everyday goods. However, economic theory claims that different market situations and negotiated products (i.e. SLAs) demand different negotiation protocols in order to reach the highest-possible overall efficiency of the system. Thus we argue that next generation service infrastructures will be based on a global service economy where several different service markets and thus protocols are present at any given point in time. In this paper we present a novel approach for such an infrastructure, based on structured protocol descriptions and software-agent technology.