Local energy production and distributed energy storage facilities will take a prominent position in the future smart grid along with the challenge of sustainability. To cope with that, smart grid simulation platforms are needed in order to analyze the problems of two-way data and energy flow. The Power Trading Agent Competition (Power TAC) provides an open source, smart grid simulation platform to enable various smart grid studies from the perspective of sustainability. In this paper, we present AgentUDE, which competed in the Power TAC 2014 and 2015 Final games as a broker agent. Here, we create and formalize information system artefacts for the electricity trading problem in a continuous and competitive environment. The main trading problem is partitioned to smaller problems to reduce the complexity. Therefore, wholesale and retail electricity market activities are individually discussed for AgentUDE14. In 2015 competition, we added a capacity control capability to AgentUDE14, which was introduced as AgentUDE15. We show that AgentUDE is a successful broker agent in many metrics, analyzing its performance in controlled experiments and international tournaments. We have also reviewed the tournament data from the winner agent’s point of view.

The current transformation process of how energy is supplied attracts great interest from many different market players.As a consequence, many proprietary solutions for "smart" energy applications are flooding the market.This turns out to be rather a problem than part of the solution for the systematic development of future energy grids.Additionally, the absence of necessary standards blocks further developments that enable the creation of novel, market-driven and hybrid control solutions.To overcome these problems, we suggest a standardized control approach for hybrid energy systems by means of a so called Energy Option Model (EOM).This unifying model and the therewith developed decision support system provides the necessary technical understanding and the economic assessment options for network-connected energy conversion systems.Thus, it can be used for single onsite systems as well as for aggregated systems that are controlled in centralized or decentralized manner.This paper presents and discusses exemplary use cases for our EOM that illustrate the centralized as well as the decentralized use of our approach within hybrid energy systems.Overall, we believe that the EOM represents the key approach for a further systematic development of an open hybrid energy grid.

The paper interprets a smart grid as an enhanced service environment. For a reliable, autonomic integration of services without permanent actions of experts, the Service Discovery has to agree on the semantic interpretation of nonfunctional and technical criteria. The proposed service environment for smart grids applies our Service Discovery framework ACTAS (Adaptive Composition and Trading with Agents for Services), which is based on software agents and enhances SOC with ontologies for the classification and quasi-standardization of criteria and their constraints for a commonly agreed Service Discovery, Composition, and Selection taking advantage of established algorithms.

Discovery is the task of locating (Web) Services by means of their semantic annotation. Semantic Web Services (SWS) annotate semantic information about their functionality through capability descriptions (e.g. WSMO, OWL-S). Many approaches of automatic discovery and composition of business services take advantage from SWS. However, discovery and composition of general services or discovery based on other service aspects as functionality are neglected. The paper introduces models of a Discovery Framework called ACTAS (Adaptive Composition and Trading based on Agents), which allows the matching through semantic characteristics and algorithms. Semantic service characteristics, published through an ontological repository, wrap service property objects and constraints. The description of services with the SWS interface needs rather an expert (e.g. in description logic (DL)). Semantic Service Characteristics can offer interfaces adapted for a definite user groups or domains. They allow the keeping of domain specific ontologies.

The specification of join point selections (also known as "pointcuts") is a major design issue in Aspect-Oriented Software Development. Aspect-oriented systems generally provide specific language constructs (subsumed by the term "pointcut language") for specifying such a join point selection. Pointcut languages differ widely with respect to their syntax and semantics. Consequently, developers familiar with one specific language can hardly benefit from this knowledge when designing and implementing pointcuts in another language. This implies that developers working with different aspect-oriented languages can hardly communicate their design to each other, and knowledge about aspect-oriented design can hardly be transferred among developers developing in different languages. In order to overcome this problem, we present novel specification means based on the UML to represent diverse ways of join point selections — without relying on language-specific syntax and semantics. Instead, the proposed language constructs are able to express join point selections in a variety of different aspect-oriented programming languages.

Active database management systems have been developed for applications needing an automatic reaction in response to certain events. Events can be simple in nature or complex. Complex events rely on simpler ones and are usually specified with the help of operators of an event algebra. There are quite a few papers dealing with extensions of existing event algebras. However, a systematic and comprehensive analysis of the semantics of complex events is still lacking. As a consequence most proposals suffer from different kinds of peculiarities. Independent aspects are not treated independently, leading to shady mixtures of aspects in operators. Moreover, aspects are not always treated uniformly. Operators may have other semantics than expected. The paper addresses these problems by an extensive and in-depth analysis of the foundations of complex events. As a result of this analysis, a (formal) meta-model for event algebras is introduced that subdivides the semantics of complex events into elementary, independent dimensions. Each of these dimensions are discussed in detail. The resulting language specification fulfils the criteria for a good language design (like orthogonality, symmetry, homogeneity, lean set of language constructs) to a large extent.

OOPS is an object-oriented programming environment with integrated data management facilities. It is designed to especially support advanced applications, like engineering and office applications. Rich data modeling facilities, including the concepts of classification, generalization, and aggregation are provided. Additionally, complex semantic integrity constraints, exception-handling mechanisms, and triggers can be specified. Since all these facilities are integrated into a single language, the artificial distinction between database language and programming language is no longer existent. The main features of the programming language and the architecture of OOPS are presented.>

The original approach of optimistic concurrency control /2/ has some serious weaknesses with respect to validation, long transactions and starvation. This paper first discusses design alternatives which avoid these disadvantages. Essential improvements can be reached by a new validation scheme which is called snapshot validation. The paper then discusses a validation scheme which especially supports read transactions, so that the number of backups decreases substantially. Finally a very simple solution for the starvation problem is presented. The proposal is perfectly consistent with the underlying optimistic approach.

No abstract available.

A non-procedural query language for network databases is described. The language is very powerful as compared to other implemented languages. It allows to formulate complex queries which, among other things, include conditions for CODASYL-sets and conditions for n:m-relationships. Cyclic database structures can be processed to some extent.Note: This report is not written for the "naive" user of NOAH, and is not meant to replace a NOAH manual. Instead, this report describes the foundations, the underlying concepts, and the structure of the language in more theoretically oriented, technical terms.This research was performed at the university of Hagen, West Germany, and was partially supported by Triumph Adler AG, Nürnberg, West Germany.