Robert Brehm

A Framework for a Dynamic Inter-connection of Collaborating Agents with Multi-layered Application Abstraction Based on a Software-Bus System

With the currently ongoing and necessary process to define standards for multi-agent systems, their potential for adaptation to specific underlying system requirements becomes increasingly challenging. Especially in those applications, where multi-agent systems are coupled to hard- and software systems, which have specific operational characteristics, such as specific response times or quality-of-service requirements. As a result, it is proposed to separate the high-level decision making based on standardized multi-agent systems and the low-level system control into two layers. In this paper, based on a publisher/subscriber software-bus system, we propose a framework which allows dynamic allocation and linking of agents to underlying low-level hardware control. The concept of the framework and its architecture is introduced and an application example is outlined.

A distributed multi-agent linear bi-objective algorithm for energy flow optimization in microgrids

A distributed linear bi-objective optimization algorithm for management of energy flow in a microgrid with individual agents is introduced. In contrast to widely used centralized approaches for energy management a distributed multi-agent scheme for optimization of energy flow within a microgrid consisting of local energy resources and storage capacities is presented which is based on the auction algorithm for assignment problems originally introduced by Bertsekas in 1979 [1]. It is shown that the topology of a microgrid can be represented as a bipartite graph and mathematically be described as a classical transportation problem. This allows applying an auction algorithm scheme in a distributed way where each energy supply system node is either a source or a sink and is represented by an individual acting agent. The single-objective approach is extended towards bi-objectivity to build a framework which gives each agent freedom and authority to intelligently influence the global decision making (optimization) with respect to its own individual objectives and therefore a distributed bi-objective optimization for the energy flow in the microgrid with individual agent objectives is achieved. In the introduced framework computational intelligent agents enhance the intelligence of the global decision making based on their individual agents intelligence.

A DP based scheme for real-time reconfiguration of solar cell arrays exposed to dynamic changing inhomogeneous illuminations

The overall energy conversion efficiency of solar cell arrays is highly effected by partial shading effects. Especially for solar panel arrays installed in environments which are exposed to inhomogeneous dynamic changing illuminations such as on roof tops of electrical vehicles the overall system efficiency is drastically reduced. Dynamic real-time reconfiguration of the solar panel array can reduce effects on the output efficiency due to partial shading. This results in a maximized power output of the panel array when exposed to dynamic changing illuminations. The optimal array configuration with respect to shading patterns can be stated as a combinatorial optimization problem and this paper proposes a dynamic programming (DP) based algorithm which finds the optimal feasible solution to reconfigure the solar panel array for maximum efficiency in real-time with linear time complexity. It is shown that the effective increase of efficiency is up to 50%. An experimental platform to evaluate and validate the DP algorithm performance under real conditions to proof the concept of the proposed reconfiguration scheme is introduced.

Investigations on the performance of a mechatronic system for water well rehabilitation using high power ultrasonics

In Denmark the public water supply is practically 100% served by groundwater abstracted from nearly 20.000 water wells. During time of operation the productivity from a well will often decrease drastically. This impaired performance is usually caused by well clogging. This clogging makes the well economically inefficient for the operator and therefore needs to be rehabilitated. This article examines the performance and evaluates the effectiveness of high power ultrasonics for water well rehabilitation. Special focus is drawn to the inconsistent efficiency of the currently, rarely used ultrasonic cleaning method caused by the specific varying conditions in water wells and correlated ultrasound intensity losses. The scope for improving the, in Denmark, rarely used ultrasonic cleaning method efficiency is investigated and suggestions for improvements based on a proof-of-concept prototype are given based on empirical- as well as theoretical studies.Copyright

Investigation of the limits of a fibre optic sensor system for measurement of temperature distribution.

The aim of this project is to develop an innovative temperature sensor system which is able to measure the temperature distribution along a fibre optical cable. This technique for temperature measurement is based on Optical Time Domain Reflectometry (OTDR)