Holger Wache

University of Applied Sciences and Arts Northwestern Switzerland | FHNW · School of Business

A dramatic increase in network capacity demand is to be expected in the future, especially at times of high production or consumption. This is due to the electrification of the global energy system and a shift towards distributed power production from sustainable sources. Energy management solutions have been proposed that help mitigate high costs...

We present a new method to control an aggregated electric load profile by exploiting the flexibilities provided by residential homes. The method is based on a common energy price combined with inclining block rates, broadcasted to all households allowing them to minimize their energy provisioning cost. The distributed home energy management systems...

The continuous increase of competitiveness of renewable energy in combination with the necessity of fossil fuel substitution leads to further electrification of the global energy system and therefore a need for large-scale power grid capacity increase. While physical grid expansion is not feasible for many countries, grid-driven energy management i...

The increasing number of volatile energy sources, such as solar power plants, challenges the power network operators, the energy brokers as well as the electricity market actors. In this work, a multi-agent based approach will be introduced that allows multiple households to trade flexibilities, on top of the usual selling of produced energy to the...

Large scale telecommunications networks need to be continuously monitored to detect problems and react accordingly to ensure the networks stability. Current monitoring systems are well capable to monitor such large scale installations for simple situations like failing routers, links or abnormal link utilization. However, current systems fail to pr...

This paper discusses how usage patterns and preferences of inhabitants can be learned efficiently to allow smart homes to autonomously achieve energy savings. We propose a frequent sequential pattern mining algorithm suitable for real-life smart home event data. The performance of the proposed algorithm is compared to existing algorithms regarding...

This paper presents a case study of a recommender system that can be used to save energy in smart homes without lowering the comfort of the inhabitants. We present an algorithm that uses consumer behavior data only and uses machine learning to suggest actions for inhabitants to reduce the energy consumption of their homes. The system mines for freq...

In this article, the "SmartStability" concept is introduced and first results are shown. The concept is based on the exchange of electrical energy within a network of households that possess temporal flexibilities in consuming or providing energy from or to the network. The exchange is governed by a market-economic negotiation principle between the...

Several European countries are increasingly focusing on renewable energy in order to satisfy their demand. A core problem of these sources is their reliability, which means less continuously available energy is accessible. Smart grids are trying to cope with this problem by adding intelligence to the net, which tries to adjust the load according to...

Location-based services (LBS) in general allow information processing with respect to three dimensions: space, time and semantics/content. Social me-dia allows using people's social network for information processing. The wide use of both techniques motivates to merge them into new application domains. In this paper we present our first experiences...

The Smart Grid will largely increase the amount of measurement data that needs to be processed on distribution grid level in order to fulfill the promised smart behavior. Many modern information systems are capable of handling the produced data amounts quite well. However they are usually highly specialized systems that are costly to change or limi...

Software-as-a-Service (SaaS) is a delivery model whose basic idea is to provide applications to the customer on demand over the Internet. In contrast to similar but older approaches, SaaS promotes multi-tenancy as a tool to exploit economies of scale. This means that a single application instance serves multiple customers. However, a major throwbac...

In this paper we describe an approach to graphically externalize the cloud potential of a company, considering its architectural description. For this purpose it is shown how current architectural description can be extended, in terms of knowledge and graphical representation. The goal is to focus on the most important features and aspects to consi...

Today we’re witnessing the necessity to align Business and Information Technology (IT). Based on the assumption that businesses in different sectors of the economy will require IT for different reasons and in different ways, this paper describes the challenges arising and our solutions concerning that alignment. Our idea is to link human interpreta...

Handling changes of business processes, and making sure systems are up and running after a change in the business process with minimum downtime is something which has been of interest to researchers for long and there have been several approaches proposed for it. With Cloud computing becoming increasingly popular businesses require a strong system...

Cloud computing has emerged as a strong factor driving companies to remarkable business success. Far from just being an IT level support solution cloud computing is triggering changes in their core business models by making them more efficient and cost-effective. This has generated an interest for a lot of companies to try and adopt cloud computing...

Models are a valuable knowledge asset for an enterprise. An enterprise model repository can improve sharing of enterprise knowledge and thus can exploit the use of the knowledge for various applications. In this work we present a framework for the organisation of enterprise models. The framework was derived from enterprise architecture frameworks....

Research in Cooperative Query answering is triggered by the observation that users are often not able to correctly formulate queries to databases that return the intended result. Due to a lack of knowledge of the contents and the structure of a database, users will often only be able to provide very broad queries. Existing methods for automatically...

The extensive work on Knowledge Engineering in the 1990s has resulted in a systematic analysis of task-types, and the corresponding problem solving methods that can be deployed for different types of tasks. That analysis was the basis for a sound and widely accepted methodology for building knowledge-based systems, and has made it possible to build...

E-Government is no longer a concern of single public administration units. State wide E-Government strategies, E-Government architectures and frameworks are established now and public administrations are willing to suit the action to the word. Also, semantically enriched techniques for service description, discovery and invocation are ready to come...

In this paper we introduce a prototype job portal which uses semantically annotated job oers and applicants. In our opinion, using Semantic Web technologies substantially increase market transparency, lower transaction costs and speed up the procurement process. How- ever adding semantics is not a panacea for everything. We identify some outstandin...

EU-IST Network of Excellence (NoE) IST-2004-507482 KWEB Deliverable D2.1.3.1 (WP2.1) This deliverable gives an overview of concepts and methods necessary for achieving scalability through modularization of ontologies. This includes partitioning algorithms for large ontolo-gies into smaller modules, distributed reasoning, e.g. distributed RDF queryi...

EU-IST Network of Excellence (NoE) IST-2004-507482 KWEB Deliverable D2.5.4 (WP2.5) Keyword list: description logics, ontology language, query language, RDF, OWL DL, OWL-E The current deliverable surveys a number of real-world use cases encountered in the course of the KnowledgeWeb project which demonstrate limitations of the Semantic Web ontology l...

Governmental processes are complex and knowledge-intensive. Most pro- cess management systems fail to support them in an adequate way. On the other hand semantic technologies like Semantic Web Services allow to incorporate knowledge in process. But often this techniques are overdimensioned and can not be executed properly. Here we proposed a more p...

An issue that is equally arising both from social networks and the Semantic Web is the fact that, without the consistent use of the same identifier for an object across systems, it is unnecessarily hard to perform information integration. We are addressing this issue where both fields intersect, namely in the context of FOAF profiles, which describ...

More and more companies are going to use Internet for their job procurement process, i.e. to search for job seekers and publish open positions. However, common search techniques based on classical key-word search fail to match job seekers with job offers since particular (over-constraint) queries return no answers and search engines are un-able to...

Research in Cooperative Query answering is triggered by the obser- vation that users are often not able to correctly formulate queries to databases that return the intended result. Due to a lack of knowledge of the contents and the structure of a database, users will often only be able to provide very broad queries. Existing methods for automatical...

While using semantic data can enable improved retrieval of suitable jobs or applicants in a recruitment process, cases of inconsistent or overly specific queries which would return no results still have to be dealt with. In this paper the extension of a semantic job portal with a novel query relaxation technique is presented which is able to return...

Ontology management and maintenance are considered cor- nerstone issues in current Semantic Web applications in which semantic integration and ontological reasoning play a fundamental role. The ability to deal with inconsistency and to accommodate change is of utmost importance in real- world applications of ontological reasoning and management, wh...

We take a general perspective on alignment in order to develop common,theoretical foundations for the subject. The deliverable comprises,a comparative,study of di erent mapping,languages by means,of distributed first-order logic, and a study on category-theoretical modelling of alignment and merging by means of pushout-combinations. Keyword list: s...

Approximation has been identified as a potential way of re- ducing the complexity of logical reasoning. Here we explore approxi- mation for speeding up instance retrieval in a Semantic Web context. For OWL ontologies, i.e., Description Logic (DL) Knowledge Bases, it is known that reasoning is a hard problem. Especially in instance retrieval when th...

EU-IST Network of Excellence (NoE) IST-2004-507482 KWEB Deliverable D2.5.3 (WP2.5) Keyword list: description logics, ontology language, query language, RDF, OWL DL, OWL-E In D2.5.2 "Report on Query Language Design and Standardisation", we have investigated query answering of conjunctive queries in the OWL-QL framework, including treating RDF triple...

In many application scenarios, the use of the Web ontology language OWL is hampered by the complexity of the underlying logic that makes reason- ing in OWL intractable in the worst case. In this paper, we address the question whether approximation techniques known from the knowledge representation lit- erature can help to simplify OWL reasoning. In...

EU-IST Network of Excellence (NoE) IST-2004-507482 KWEB Deliverable D2.1.1 (WP2.1) This deliverable gives an overview of methods necessary for achieving scalability. This includes general methods for approximating symbolic inference engines and for compiling knowledge bases, different methods for modularisation and distributed reasoning, and a surv...

The need to represent mappings between different ontologies has been recognized as a result of the fact that different ontologies may partially overlap, or even represent the same domain from different points of view. Unlike ontology languages, work on languages to represent ontology mappings has not yet reached a state where a common understand- i...

Since the last decade, management trends as just-in-time, or shortened time-to-market and a more flexible consideration of customer' demands are leading to a rapid change of market requirements cooperative relationships in logistic networks. In distributed logistics the knowledge about products, production processes, and distribution are becoming c...

We review the use on ontologies for the integration of heterogeneous information sources. Based on an in-depth evaluation of existing approaches to this problem we discuss how ontologies are used to support the integration task. We evaluate and compare the languages used to represent the ontologies and the use of mappings between ontologies as well...

Specification -- Topic 11 Open GIS Consortium (OGC) International [OGC, 1999] Recommendations on Metadata (V 2.0) Center for Earth Observation Programme (CEO) EU The Dublin Core, for example, was developed by an international working group of librarians to organize electronic libraries [Weibel et al., 1995] , [Weibel, 1999]. Since 1996, the Dublin...

To date the World Wide Web consists mainly of loosely structured data. In order to change this situation and make the Semantic Web successful this vast amount of data needs to be given structure and more importantly, meaning. Ontologies are considered a support in this process as they help us explicitly define concepts. A drawback when using ontolo...

In the past a lot of approaches concerning the integration of heterogeneous information sources are developed. In the last years the semantics, which play an important role during the integration task, come into the focus leading to the so called ontology-based integration approaches. This paper provides a survey of most prominent ontologybased int...

This paper discusses the use of contextual reasoning, i.e. context transformation for achieving semantic interoperability in heterogeneous information systems. We introduce terminological contexts and their explication in terms of formal ontologies. Using a real-world example, we compare two practical approaches for context transformation one based...

We review the use on ontologies for the integration of heterogeneous information sources. Based on an in-depth evaluation of existing approaches to this problem we discuss how ontologies are used to support the integration task. We evaluate and compare the languages used to represent the ontologies and the use of mappings between ontologies as well...

Environmental information systems have gained more importance both in the public administration and industry since the beginning of 1990. For example, in public administration, every state in the Federal Republic of Germany has developed a type of environmental information system. National and European legislation demanding far reaching transparenc...

Environmental information systems have gained more importance both in the public administration and industry since the beginning of 1990. For example, in public administration, every state in the Federal Republic of Germany has developed a type of environmental information system. National and European legislation demanding far reaching transparenc...

We present a new approach, which proposes to minimize the numerous problems existing in order to have fully interoperable GIS. We discuss the existence of these heterogeneity problems and the fact that they must be solved to achieve interoperability. These problems are addressed on three levels: the syntactic, structural and semantic level. In addi...

Mediators are middleware components that provide a exible integration of several heterogeneous information systems. But current approaches ignore that each information has to be considered in its context. Besides the integration the information has to be also converted from its source context into the context of the integrated view in order to achi...

On the basis of new information technologies, today's business evolves towards distributed and cooperative service processing resulting in a network of co- operating organizations. This paradigm also influences engineering and production processes. Both the characteristics of these processes and the interoperability be- tween different organization...

. On the basis of new information technologies, today's business evolves towards distributed and cooperative service processing resulting in a network of cooperating organizations. This paradigm also influences engineering processes. Both the characteristics of engineering processes and the interoperability between different organizations challenge...

Mediators are used for the integration of heterogeneous information sources. Rule--based mediators map the sources to an integrated view by transformation rules reconciling structural heterogeneity problems. But the reconciliation of semantic heterogeneity problems play a subordinate role. In this paper, we present an approach that extends rule--ba...

Compared with frame-based systems, description logics have the advantage of well-defined semantics and powerful inferences. In order to exploit these advantages in technical domains, the ability to use concrete domains is needed, e.g. systems of (in)equalities over (non)linear polynomials to handle physical laws. Existing systems can only cope with...

Mediator specification and terminology development are two labor-intensive tasks that are serious obstacles to the widespread use of mediator-based systems. In this paper, we propose a three-step approach to acquire mediator specifications and to gradually build a domain terminology at the same time. The approach also allows the support of software...

We discuss the extended LP environment of the project VEGA (knowledge validation and exploration by global analysis), a toolbox that supports the development and maintenance of declarative knowledge bases. The knowledge is represented in a declarative language that merges Horn logic with finite domains, sort hierarchies, functions, and integrity co...

> U = R I or m = r f ffl procedures in the mechanical engineering domain there are procedures verifying and/or calculating values like temperature in crankshaft ffl ... Therefore, to describe components and their relationships a KR system needs a rich and expressive language. In our opinion, terminological systems provide such a language. On the in...

Information technology support for complex, dynamic, and distributed business processes as they occur in engineering domains requires an advanced process management system which enhances currently available workflow management services with respect to integration, flexibility, and adaptation. We present an uniform and flexible framework for advance...

> U = R I or m = r f ffl procedures in the mechanical engineering domain there are procedures verifying and/or calculating values like temperature in crankshaft ffl ... Therefore, to describe components and their relationships a KR system needs a rich and expressive language. In our opinion, terminological systems provide such a language. On the in...

Using quantitative models of simple mechanisms as an example domain, we show how the basic principles of consistency-based diagnosis can be implemented using description logics with expressive concrete domains. In addition, description logics provide the inference services necessary to organize and validate model libraries, an aspect that is neglec...

Compared with frame-based systems, description logics have the advantage of well-defined semantics and powerful inferences. In order to exploit these advantages in technical domains, the ability to use concrete domains is needed, e.g. systems of (in)equalities over (non)linear polynomials to handle physical laws. Existing systems can only cope with...

We informally introduce TaxLog, a close integration of logic programming and terminological reasoning. Terminological systems are handling declarative logic-based descriptions of conceptual knowledge. Most of them restrict their expressiveness and focus on (efficient) reasoning algorithms for certain services. This imposes principal restrictions on...

The use of logic-based representations in distributed environments such as the semantic web has led to work on the representation of and reasoning with mappings between distributed ontologies. Up to now the investigation of reasoning methods in this area was restricted to the use of mapping for query answering or subsumption reasoning. In this pape...

We take a general perspective on alignment in order to develop common theoretical foundations for the subject. The deliverable comprises a comparative study of di erent mapping languages by means of dis- tributed first-order logic, and a study on category-theoretical modelling of alignment and merging by means of pushout-combinations. Keyword list:...

Deliverable D2.3.9 (WP2.3) presents a study on theoretical aspects of ontology lifecycle and dynamic maintenance. Several crucial topics are analysed, ranging from logical groundwork of ontology dynamics based on belief-change theory, through semantics of ontology diffs, to multi- version reasoning. Building on the theoretical studies, ba sic pract...