Wolfgang Renz

• Prof. Dr.rer.nat.
• Professor (Full) at HAW Hamburg

For integration of growing amounts of volatile renewable energy in the European electricity system, reliable weather prognosis gains importance. But, depending on weather conditions, forecast reliability of wind speed for predicting wind power can vary drastically with time. Thus, relevance of risk-aware system operation strategies is increasing ba...

Due to the European trend of rising penalty costs for causing imbalances, aggregators face higher financial risks when pooling many renewable energy systems in regions with frequent grid congestion. Intra-day deviations from prognosis-based day-ahead schedules can be crucial in case of premature or delayed feed-in reduction. To reduce this risk, th...

Virtual power plant operators with pools of large amounts of regenerative power face high imbalance risk in case of uncertain day-ahead weather prognosis. In contrast to forecast-based balancing at low risk, they need a strategy for operating distributed energy resources (DER) like an insurance scheme under high risk circumstances. In this paper, w...

Building renovation plays a huge role in reducing CO2 emissions and energy demand. To understand the effects of different renovation strategies, expert users and decision makers need to explore urban renovation scenarios both spatially and temporally. The ongoing GEWISS project aims to do this by providing a GIS (Geographical Information System) to...

In the context of European climate goals municipalities have an increasing interest in an accurate estimation of current and future energy demand in buildings, as the domestic energy consumption is one of the major adjusting screws for the reduction of electrical and thermal energy consumption, whereas the demand for space heating has the highest i...

A growing number of Distributed Energy Resources will be connected to the grid. These distributed energy resources have different technical capabilities, operational constraints and are distributed throughout the electricity network which results in an increasing operational complexity. Aggregators controlling these resources in a virtual power pla...

The purpose of this contribution is to show 1. a systematic perturbation-theoretical method of solving multivariate Fokker-Planck equations (FP eq.) as they appear in galactic dynamics. 2. that it is not only important to consider the cooling of the stellar disk by birth of new stars but also to include stellar death processes in the equation. This...

The increasing dissemination of Distributed Energy Resources (DER) has lead to the introduction of the Virtual Power Plant (VPP) concept to enable small and medium sized consumers, producers and prosumers in larger markets. Although the market participation of these VPPs in classical markets can cover many different business cases, the growing degr...

A key requirement to realize modern distributed systems is the ability to adapt the system’s behavior autonomously at runtime towards changing environmental conditions, in order to preserve their operation even in the presence of uncertain changes. The different parts of such a distributed self-organizing system have to be coordinated in order to a...

Currently, bike-sharing systems undergo a rapid expansion due to technical improvements in the operation combined with an increased environmental and health awareness of people. When it comes to the acceptance of such systems the reliability is of great importance. It depends heavily on the availability of bicycles at the stations. But, in spite of...

A key requirement for the realization of modern distributed systems is their ability to dynamically adapt their behavior to changing environmental conditions to preserve their operation even in the presence of uncertain changes. In order to accomplish this, the different parts of such a self-organizing system have to be coordinated to achieve meani...

The growing dissemination of distributed energy resources with steadily changing power flows in combination with the rising demand for electricity leads to increasing problems in grid management. Planning and managing these resources with information and communication technology as well as automation technology for optimal operational planning whil...

The Smart Grid is a paradigm shift towards a bi-directional energy and communication system relying on rich information exchange among all involved actors. Based on the experience of the participation in the CEN-CENELEC-ETSI Smart Grid Coordination Group (SG-CG) report creation for the EU-Mandate 490 "European Smart Grid Standardization"[1], the EU...

The increasing number of volatile Distributed Energy Resources (DERs) in the electricity grid implies a rising level of complexity and dynamics. The integration and management of these DERs have lead to the introduction of the aggregator role, with the aim of providing energy services to system operators and the market. With regard to the often cha...

After the liberalization of energy markets in Europe the Virtual Power Plant (VPP) concept has been introduced to enable smaller Distributed Energy Resources (DER) to participate in larger markets. Although markets and processes between VPP-aggregators and smart grid actors, such as system operators and balance responsible parties, have been improv...

The Smart Grid is a paradigm shift towards a bidirectional energy and communication system relying on rich information exchange among all involved actors. Based on the experience of the participation in the CEN-CENELEC-ETSI Smart Grid Coordination Group (SG-CG) report creation1 for the EU-Mandate 490 "European Smart Grid Standardization" [1], the E...

Bike-sharing systems undergo a rapid expansion due to technical improvements in the operation combined with an increased environmental and health awareness of people. The acceptance of such system depends heavily on the availability of bikes at stations. In spite of truck-based redistribution efforts by the operators, stations still tend to become...

In the ongoing GEWISS project it is planned to implement a geographical heat information and simulation system. It shall provide a planning and simulation tool for the interlinking of urban development and district heat network development to support the political decision making process in the City of Hamburg. The system shall combine macroscopic...

Over one decade of research in engineering of self-organization (SO) has established SO as the decentralized way to build self-adaptive systems. However, such SO systems even when well engineered may, under certain conditions, exhibit unwanted dynamical behavior, e.g. performance may decrease and/or starvation may occur. A promising concept to over...

Today, mass presence of distributed energy resources (DERs) connected to the grid is often seen as having adverse effects on grid reliability and robustness. The apprehension is that it complicates or even compromises network management by distribution system operators (DSOs). The central aim of the Open System for Energy Services (OS4ES) project...

Demand-Side-Management (DSM) is one of the key factors in the future smart grid, utilizing the consumer side as an additional degree of freedom for planning and controlling the grid. Caused by the growing dissemination of distributed energy resources (DERs), the classical top-down oriented modus operandi transforms towards new operational models. W...

Die herkömmliche Struktur der Ingenieurstudiengänge weist in der Eingangsphase häufig ein Nebeneinander von isolierten Grundlagenmodulen auf. Die Notwendigkeit der zu vermittelnden Kompetenzen und ihre Beziehungen zu den Anwendungen des Studienfachs ausreichend deutlich zu machen, stellt dabei eine besondere Herausforderung dar. Auch gewährleistet...

Simulationen sind ein entscheidender Teil, um intelligente Lösungen und Konzepte für zukünftige Smart Cities zu finden. Bevor Konzepte und Lösungen in der Realität umgesetzt werden können, ist es unerlässlich sie mit Hilfe von Simulationen auf ihre Tauglichkeit zu überprüfen. Im Rahmen des GEWISS Projektes soll ein geographisches Wärmeinformations-...

Dynamic and volatile grid conditions caused by the growing amount of renewable energy producers require the operation of large-scale distributed Demand-Side Management (DSM) applications. This is one of the tasks of the aggregator role in smart grid operation according to the Smart Grid Architecture Model (SGAM). For the optimization of distributed...

Demand-Side-Management (DSM) is one of the key applications in the future smart grid, creating a new degree of control in order to reduce losses and fluctuations caused by volatile distributed energy resources (DERs). To integrate the consumer side, several approaches like flexible tariffs, have been proposed and tested. However, many of these appr...

This paper presents a scalable integration approach for algorithms and models written in fourth generation (programming) languages for massive Smart Grid simulations as well as applications. While fourth generation languages (4GL) focus on rapid application development and the reduction of lines of code, they lack of integration and scalability fea...

The current development in the energy sector leads towards decentralized and distributed power generation. The coordination of the small- and medium-scaled distributed energy resources (DER) as well as further energy services will be a major challenge in smart grids. Many operation concepts like the Virtual Power Plant or microgrid operation will c...

In recent years, technical improvements combined with an increasing environmental and health awareness lead to a rapid expansion of bike-sharing systems worldwide. The operation of bike-sharing systems in big cities depends mainly on the availability of bikes at stations. But bike-sharing systems in big cities exhibit the problem of system reliabil...

Coordination is an important aspect to realize Self-organizing Systems usually implemented as part of the functional properties of the system. This paper promotes a separation of concerns via a declarative approach to realize decentralized coordination in Self-organizing Multi-Agent Systems (MAS). In previous work the concept of Coordination Spaces...

The massive growth in the usage of renewable, but fluctuating energy sources in connection with the energy turnaround calls for a similar growth of the integration of flexible loads. This seems to be a vital aspect to maintain the balance between production and consumption in the transportation grid as well as in the distribution grid at low voltag...

Coordination is an important aspect to realize Self-organizing Systems usually implemented as part of the functional properties of the system. This paper promotes a separation of concerns via a declarative approach to realize decentralized coordination in Self-organizing Multi-Agent Systems (MAS). In previous work the concept of Coordination Spaces...

This chapter discusses several case studies to evaluate the methods introduced in chapter 23, Methods. Each case study focuses on a specific issue and the advanced cases build up on previous findings. The first ones are dealing with the low-level fv directly and then the scope widens to the interrelationship of multiple fv until their combination w...

With rapid development of digital technologies, building an efficient and reliable image retrieval system is always challenging in computing science and related application disciplines. This book part presents an investigation in how “Content-Based Image Retrieval (CBIR)” queries could be designed in order to achieve an extensible language understa...

In this chapter, a CBIR design based on previous work of the author (Pein, 2008) is presented. The available system already allows for a retrieval by a query string (Pein, Lu, & Renz, 2008a). In the context of this investigation, the system has been extended to support alternative user interfaces as well as a testing module used in the case studies...

In this final chapter of the section, the conclusion of this book section is given. It is summarized how the initial hypothesis has been investigated and which answer has been found. A brief summary of the achievements as well as the intended future work in this area are presented.

This chapter points out certain technologies that are often applied in a CBIR system. A prototypical retrieval system has been developed in order to evaluate the research hypothesis. Following common principles of information hiding, the software is designed to have multiple layers of abstraction. The top layer needs to be user friendly and also ha...

The research field of “Content-Based Image Retrieval (CBIR)” is closely related to several others. This chapter provides an overview of the most relevant research fields and their interrelationship regarding this investigation. For each one, a summary of recent, related research is presented. In addition, the related preliminary work of the author...

In resource–flow systems e.g. production lines resources are processed by agents applying certain capabilities to them. Such systems profit from self–organization like self– healing as they become more robust against failures. In this paper the development of a decentralized coordination process for such a system is described. The system is realize...

The construction of self–organizing Multi–Agent Systems (MAS) is still short of systematic validation methods. These are crucial for acceptance of self–organization in mainstream software engineering. Validation of such systems requires the use of formal descriptions of the underlying coordinating process during the engineering process. The here pr...

In resource-flow systems, e.g. production lines, agents are processing resources by applying capabilities to them in a given order. Such systems benefit from self-organization as they become easier to manage and more robust against failures. In this paper, we demonstrate the conception of a decentralized coordination process for resource-flow syste...

Business applications in open and dynamic service markets offer great opportunities for both consumers as well as for providers of services. However, the management of related business processes in such environments requires considerable (often still manual) effort. Specific additional challenges arise in highly dynamic environments which may lead,...

Service-orientation provides concepts and tools for flexible composition and management of large-scale distributed software applications. The automated run-time management of such loosely coupled software systems, however, poses still major challenges and is therefore an active research area, including the use of novel computing paradigms. In this...

The AgentContest 2009 provided a revised Cows and Herders scenario which extended the last year’s setting. First, additional environment objects, i.e., fences and switches, were introduced. Secondly, the team score is calculated by the net amount of herded cows at the game end. In this paper we present the design of the multi-agent system (MAS) pro...

The embedding of self-organizing inter-agent processes in distributed software applications enables the decentralized coordination system elements, solely based on concerted, localized interactions. The separation and encapsulation of the activities that are conceptually related to the coordination, is a crucial concern for systematic development p...

The embedding of self-organizing inter-agent processes in distributed software applications enables the decentralized coordination system elements, solely based on concerted, localized interactions. The separation and encapsulation of the activities that are conceptually related to the coordination, is a crucial concern for systematic development p...

The third of the S-Cube technology layers provides infrastructure capabilities for defining basic communication patterns and interactions involving as well as providing facilities for providing, for example, contextual and qualitative information about a service’s and their client’s environment and performance. Providing these capabilities to other...

In resource-flow systems, e.g. production lines, agents are processing resources by applying capabilities to them in a given order. Such systems profit from self-organization as they become easier to manage and more robust against failures. This paper proposes a decentralized coordination process that restores a system's functionality after a failu...

For reasons of authenticity, didactic concept and domain-specific content, lecturers at universities want to use their own manuscripts. Therefore, the common lecturer needs support in generating light-weight digital courses by enriching their manuscripts with reusable micromodular learning objects. Large amounts of interactive visualizations and an...

Agent Oriented Software-Engineering (AOSE) proposes the design of distributed software systems as collections of autonomous and pro-active actors, so-called agents. Since software applications results from agent interplay in Multi-Agent Systems (MAS), this design approach facilitates the construction of software applications that exhibit self-organ...

S-Cube’s Foundations for the Internet of Services Today’s Internet is standing at a crossroads. The Internet has evolved from a source of information to a critical infrastructure which underpins our lives and economies. The demand for more multimedia content, more interconnected devices, more users, a richer user experience, services available any...

The effective and reliable coordination of agent activities is a momentous problem for Multi–Agent System (MAS) developers. Particularly challenging is the decentral-ized coordination of agents that enables systems to exhibit self–organization. Natural phenomena typically serve as de-sign metaphors and developers apply Decentralized Coordi-nation M...

The integration of self-organizing processes in distributed software systems allows to equip applications with adaptive features that rise from the (inter-)actions of agents. In this paper, we address the systematic development of decentralized inter-agent processes in Multi-Agent Systems (MAS) that give rise to self-organizing properties. A system...

The steadily increasing size and complexity of distributed software systems demand the systematic construction of self-managing software architectures that reduce administrative overheads. Self-adaptive architectures are typically conceived by introducing managing entities which establish closed-loop control mechanism. Here, we propose a fully dece...

One of the most important bits of every search engine is the query interface. Complex interfaces may cause us- ers to struggle in learning the handling. An example is the query language SQL. It is really powerful, but usually remains hidden to the common user. On the other hand the usage of current languages for Internet search engines is very simp...

This paper addresses the automated management and simulation of capacity problems for motor highway infrastructures, which often cannot keep up with traffic increases produced by, e.g., cars, motorbikes and trucks. Such kinds of problems require rather intelligent highway infrastructure management with strategies with, often, contradictory goals: O...

Organization–oriented modeling approaches are established tools for Agent–Oriented Software Engineering (AOSE) efforts. Role and Group concepts are prevalent concepts in the design of agent–based applications. These allow the definition and partition of static organizational structures and facilitate the description of agent behaviors in terms of r...

The design of agent-based software applications is supported by modeling approaches that focus on the design of individual agents as well as their arrangement in organizational structures. However, it is a challenging task to deduce the collective system behavior from the sum of designs of the autonomous, pro-active actors and their collaboration c...

Self-organizing systems promise new software quality attributes that are very hard to obtain using standard software engineering approaches. In ac- cordance with the visions of e.g. autonomic computing and organic computing, self-organizing systems promote self-adaptability as one major property helping to realize software that can manage itself at...

The integration of self-organizing processes in distributed software systems allows to equip applications with adaptive features that rise from the (inter-)actions of agents. In this paper, we address the systematic development of decentralized inter-agent processes in Multi-Agent Systems (MAS) that give rise to self-organizing properties. A system...

The systematic conception of decentralized and self-adaptive software systems, as demanded for the run-time management of today’s distributed, multi-tier software architectures, is an active research area. Here, we discuss a coordination architecture that facilitates the enactment of externalized coordination models in Multi-agent Systems (MAS). Co...

The purposeful development of MAS, particularly when addressing complex, decentralized application architectures, demands the ability to anticipate the effects of agent coaction. Sophisticated design and modeling tools support the development of individual agent models and their arrangement in organizational structures. However, only limited suppor...

Enabling distributed software systems to purposefully self-organize, i.e. to adapt to dynamically changing execution contexts by the collective adjustment of individual components, challenges current development practices. Since the dynamics of self-organizing systems arise from agent coaction, developers cannot directly infer the macroscopic syste...

One of the most important bits of every search engine is the query interface. Complex interfaces may cause users to struggle in learning the handling. An example is the query language SQL. It is really powerful, but usually remains hidden to the common user. On the other hand the usage of current languages for Internet search engines is very simple...

This paper proposes a generic design for 3D model retrieval. It has been developed in cooperation with EADS, which deals with Computer Aided Design / Computer Aided Engineering (below CAD/CAE) data through the product life cycle. Sharing these models with users across the enterprise is a challenging task. CAD/CAE models may be hundreds of megabytes...

The Cows and Herders scenario of the 2008 Multi–Agent Programming Contest provides a challenging testbed for the coordination of intelligent agents. Our first–time participation in this contest is based on a set of BDI agents which share knowledge and coordinate by a centralized planning guidance to cope with the (possibly) hostile environment. The...

Conceiving applications as sets of autonomous agents is a prominent approach to the construction of complex distributed systems. Particularly attractive are decentralized application designs that enable adaptive, robust and scalable applications by allowing agents to self–organize. Tools to the construction of self–organizing MAS, e.g. decentralize...

Enterprise architecture management is based on a holistic view on the en- terprise addressing business and IT aspects in an integrated manner. EA management is a process to manage the complexity of the overall architecture and to improve the alignment of business and IT. In order to achieve these goals, it is necessary but not sufficient to manage...

Agent oriented software engineering (AOSE) proposes the design of distributed software systems as collections of autonomous and pro-active actors, so-called agents. Since software applications results from agent interplay in multi-agent systems (MASs), this design approach facilitates the construction of software applications that exhibit self-orga...

Software-Engineering provides techniques to ease handling the essential complexity of software. A number of engineering paradigms and architectures have been devised and each generation claims to relieve future development efforts. But to date little is known about how different development approaches affect the underlying implemenation structures,...

Since Multi-Agent Systems (MAS) are composed of sets of (inter-)acting autonomous and pro-active agents, they provide suitable concepts to the construction of self- organizing processes, promising robust and adaptive system behaviors. An examination of current software-engineering approaches to self-organizing MAS identified a lack of requirement e...

The European Physical Society (EPS) is a not for profit association whose members include 41 National Physical Societies in Europe, individuals from all fields of physics, and European research institutions. As a learned society, the EPS engages in activities that strengthen ties among the physicists in Europe. As a federation of National Physical...

The decomposition of a software system into a set of autonomous entities (agents) is a promising modeling approach to today¿s distributed applications. Agent interplay in these sets of agents, so-called Multi-agent Systems (MAS), enables the rise of complex, i. e. self-organizing and emergent system dynamics. Engineers revise agent implementations...

The utilization of self-organizing processes promises scala- bility, robustness and adaptivity in Multi-Agent Systems (MAS), solely based on decentralized coordination of individual actors. Bionic develop- ment approaches are being established, which reuse decentralized coor- dination mechanisms that are derived from natural self-organizing sys- te...

Testing and Debugging multi-agent systems (MAS) - which are inherently concurrent and distributed - is a challenging task. While complex application scenarios demand intelligent entities with autonomous reasoning capabilities, the applied reasoning mechanisms impair current approaches to validate MAS implementations. Reactive planning sys- tems, na...

Testing and Debugging multi-agent systems (MAS) – which are inherently concurrent and distributed – is a challenging task. While complex application scenarios demand intelligent entities with autonomous reasoning capabilities, the applied reasoning mechanisms impair current approaches to validate MAS implementations. Reactive planning systems, name...

Purposeful, time– and cost–oriented engineering of Multi–Agent Systems (MAS) requires developers to understand the relationships between the numerous behaviors exhibited by individual agents and the resulting global MAS behavior. While development methodologies have drawn attention to verification and debugging of single agents, software producing...

Binary decisions are common in our daily lives and often individuals can gain by choosing the minority’s side. The socio–economically inspired Minority Game (MG) has been introduced as an exact model of the famous El Farol’s Bar Problem, which exhibits complex behavior. In this paper we show that the MG players can be naturally modeled by agents us...

Recent research discussed several approaches to understand the relation between microscopic agent behavior and macroscopic multi–agent system (MAS) behavior. A structured methodology to derive these models will have impact on MAS design, evaluation and debugging. Current results have established the description of macroscopic behavior, including co...

Hydrogen diffusivities D in C14-ZrCr2H0.4 and C15-ZrCr2Hx (0.2<or=*<or=0.5) have been measured by means of pulsed-field-gradient nuclear magnetic resonance over the temperature range 130-430 K. In all the samples studied the temperature dependence of D follows an Arrhenius law above 200 K but shows marked deviations from Arrhenius behaviour below a...

A one-dimensional lattice-gas model with order preservation is considered where the occupation probabilities of sites correspond to Bose statistics as a consequence of the prescribed dynamics. The master equation for the particle-cluster dynamics at the sites is formulated. The corresponding continuum nonlinear diffusion equation is derived for the...

This paper summarizes results of a project on a massively parallel computer. The project encompasses ffl time evolution of a complex system, ffl data analysis of the relevant measures and ffl interactive visualization of the time dependent emerging structures within an integrated tool. We develop visualization and interpretation models for the gene...

The diffusivities D of hydrogen isotopes in Laves-phase hydrides have been measured by means of pulsed-field-gradient nuclear magnetic resonance over a wide temperature range. A brief review is given of the diffusion coefficients of protons in ZrCr2Hx, ZrV2Hx, ZrMo2Hx, ZrTi2Hx, TaV2Hx and HfV2Hx, and of both protons and deuterons in HfV2HyD4−y, wit...

Hydrogen diffusion in C15ZrTi2H3.7 has been measured in the temperature range 230 K to 450 K by means of pulsed-field-gradient nuclear magnetic resonance. The temperature dependence of the diffusivity shows an Arrhenius behavior, D = D0·exp(−HakBT), with an activation enthalpy Ha = 0.22 eV and a pre-exponential factor D0 = 1.8 · 10−8 m2 s−1. These...

Hydrogen diffusion in ZrH(x) (1.58 less-than-or-equal-to x less-than-or-equal-to 1.98) in the temperature range 600 K to 970 K has been measured by means of pulsed-field-gradient nuclear magnetic resonance. The activation enthalpy for hydrogen diffusion, H(a), obtained by fitting an Arrhenius expression D = D0 exp(-H(a)/k(B)T) to the diffusivities,...

Some years ago it was established that the muon catalyzed fusion phenomenon could be used for the production of energy. This fact has been causing a rebirth of interest in the universal methods of solving the quantum Coulomb three-body problem. The adiabatic hyperspherical (AHS) approach considered in this joint project has definite advantages in c...

The macroscopic diffusivities of protons in zirconium dihydrides, ZrH{sub x} (1.58 {le} x {le} 1.93), have been investigated by means of pulsed-field-gradient NMR at temperatures up to 900 K. The diffusion coefficients follow normal Arrhenius behavior, D = D{sub 0} {center dot} exp({minus}H{sub a}/k{sub B}T), with activation energies between E{sub...

A non-interacting lattice gas with order preservation in a constant external field is studied by numerical and analytical methods. The equilibrium distribution is of the Bose-Einstein type. If additional hard-core repulsion is imposed, it becomes a distribution of Fermi-Dirac type. When relaxing the order preservation condition the classical Boltzm...

The competition between adsorption and entropic repulsion of a single self-avoiding polymer trapped in quenched media consisting of parallel, adsorbing rods distributed at random in the perpendicular plane are studied by simulations and analytical arguments. The chain undergoes an adsorption transition at finite temperature which is not observed in...

We present a new approach to the linear macroscopic behaviour of polymeric liquids and melts in terms of the macroscopic variables : velocity field, density, entropy density and strain field and we discuss how the classical Maxwell model emerges as a limiting special case. The novel approach used here, which considers the strain field as an additio...