Wolfram Hardt | Technische Universität Chemnitz (original) (raw)

Papers by Wolfram Hardt

International Journal of Imaging and Robotics, Jan 27, 2013

An important aspect in the field of selforganisation in mobile Ad Hoc networks is an efficient cr... more An important aspect in the field of selforganisation in mobile Ad Hoc networks is an efficient crosslinking of all nodes in a high-dynamic network topology. This should be durable against disturbances and partial losses and distribute the net load on all net elements as evenly as possible. Past research approaches limit their solutions to the usage of a homogeneous topology on basis of a unique radio standard. This paper deals with an approach for a communication in mobile Ad Hoc networks, that integrates multiple radio standards. Thereby, the choice of the used radio standard is invisible for the respective application. For the protocol conversion on the hardware side a special interface block is used. Thus enables an economical, radio standard spanning point-to-point communication on basis of the TCP/IP protocol stack. Furthermore, the concept offers the possibility of integrating already existing devices with standardised radio modules into an existing network topology.

Communications in Computer and Information Science, Sep 17, 2014

This paper describes beta version of implementation tool which we developed to test structure ori... more This paper describes beta version of implementation tool which we developed to test structure oriented evaluation model for e-learning. The structure oriented evaluation (SURE) model consists of eight steps where included all essential parts of evaluation processes. The Mongolian University of Science and Technology and Technische Universitaet Chemnitz first time used this evaluation model for inner evaluation processes. To test advantages of SURE model we developed web based application -tool for SURE model. The beta version of tool was used in evaluation processes of above mentioned two universities. This application includes main functions of evaluation process: to create online survey based in the evaluation goal structures, to collect data online, to process data using calculation rules of SURE model, to produce graphical and statistical diagrams by evaluation scores.

Proceedings of 13th Annual Ieee International Asic Soc Conference, Feb 1, 2000

In 1 this paper we present a customized approach to performance and area optimization of asynchro... more In 1 this paper we present a customized approach to performance and area optimization of asynchronous functional blocks. First an abstract model of the block architecture is introduced and an analytical method for throughput maximization is described. Secondly, area optimization can be performed with respect to data dependencies and merged data paths. These methods have been implemented and validated by several examples. A first chip implementing all relevant architecture blocks has been produced. The chip is named FLYSIG 2 and operates completely delay-insensitive.

The proposed research work represents a generic, energy-efficient concept for the synchronised lo... more The proposed research work represents a generic, energy-efficient concept for the synchronised logging, processing and visualisation of any kind of sensor data. The concept enables a chronological coordination and correlation of information from different, distributed sensor networks as well as from any other self-sufficient measurement systems. Based on the achieved relation between the several sensor sources, the information quality can be increased significantly. Therefore, the system-wide description of the monitoring scenario and each data set is realised in XML. Accordingly, the aggregated, heterogeneous sensor information are convertible into multiple output formats. Dependent on the application specific requirements for the visualisation, we are able to consider additional meta-information from the test environment to optimise the data representation. The definition of advanced data fusion techniques and pre-processing mechanisms allows a selective data filtering to shrink the network load. To evaluate of basic usability requirements and the efficiency of the proposed concept, an automotive sensor network represents a capable test system for the proposed framework. Within the demonstrator, the available on-board measurement systems were extended by high-precision sensor nodes, which establish wireless sensor network topology. Afterwards, the correlated measurement information were converted and visualised for several professional data analysis tools, e.g., jBEAM, Google Earth, and FlexPro.

Kurzfassung. Die vorgestellte Arbeit präsentiert ein geschlossenes Konzept für die synchronisiert... more Kurzfassung. Die vorgestellte Arbeit präsentiert ein geschlossenes Konzept für die synchronisierte Erfassung, Verarbeitung und Aufbereitung beliebiger Sensor-Informationen. Es ist nun möglich, heterogene Sensornetze sowie dedizierte, autarke Messsysteme zeitlich zu koordinieren und entsprechend in Relation zu setzen. Auf Basis von XML erfolgt die ganzheitliche Beschreibung des Monitoring-Szenarios und die Einordnung der einzelnen Datensätze. Die Informationen können nun in beliebigen Ausgabeformaten anwendungsspezifisch definiert und visualisiert werden. Zusätzlich ermöglichen Mechanismen zur gezielten Messwert-Vorverarbeitung und -Filterung eine Senkung des benötigten Datenvolumens. Die Funktionalität des vorgestellten GREASE-Frameworks 1 wird am Beispiel eines geschlossenen Test-Systems aus dem Automotive-Bereich evaluiert. Dabei wird die vorhandene Sensorik eines Kfz-Bordnetzes mit einem zusätzlichen Netzwerk aus Sensorknoten verfeinert. Die korrelierten Daten werden anschließend für die Visualisierung mittels Google Earth, jBEAM und anderen Lösungen aufbereitet.

Testing is still the only way to verify complex systems. As different technologies for testing sm... more Testing is still the only way to verify complex systems. As different technologies for testing small components of a system are established, e.g. unit tests, no common methodologies or approaches exists for testing the whole systems. Reasons for this purpose is the diverseness of the systems to be tested. But during development, especially the testing of whole systems, composed of distributed and communicating subsystems, is very important to find errors or weaknesses in the designs. Since the complexity of such systems causes an immens amount of testcases, an automated process is preferable.

In this paper, a new Energy-Balanced, Cooperative Routing approach (EBCR) for radio standard span... more In this paper, a new Energy-Balanced, Cooperative Routing approach (EBCR) for radio standard spanning mobile Ad Hoc networks (MANETs) will be introduced and evaluated. Past research approaches are limited to the usage in homogeneous topologies on basis of a unique radio standard. The proposed reactive EBCR provides an efficient routing of data in heterogeneous multi-standard network topologies. In addition to an improved reachability, a primary objective is to balance the overall power consumption in each operating node to prolong the lifetime of the whole topology. Instead of using static cost factors for the route path calculation, EBCR integrates a dynamic cost vector for the handling and processing of a data packet. This includes parameters like the required field strength for the data transmission and the node's current energy level to calculate the cooperative, optimal route path. Thereby, EBCR operates only on the basis of local network information. For evaluating the conceptual advantages of this approach, multiple scenarios with static and high-dynamic network topologies have been analysed in a dedicated simulation environment. The simulation results verify the significant improvements in the topology lifetime and the reachability up to 15%.

Proceedings of the Ieee Symposium and Workshop on Engineering of Computer Based Systems, 1996

This paper describes an environment for the rapid analysis,synthesis and optimization of embedded... more This paper describes an environment for the rapid analysis,synthesis and optimization of embedded systems. Sincethe implementation of these systems is rather complicated,we propose a methodology which automates the entiredesign flow. Flexibility is achieved by allowing manualintervention which is realized via a modular implementationof algorithms which are being provided. The applicabilityof the proposed approach is shown in terms of anexample (UNIX

Ecbs, 1996

Iics, Jun 1, 2010

Load generation is asuitable concept for system leveltest of complexsystems. We present anovelapp... more Load generation is asuitable concept for system leveltest of complexsystems. We present anovelapproach especially for service based systems. Test scenarios are defined as inputs and describe aquantification of the wanted load to aservice. A test-automation component partitions and distributes these abstract load values to aset of clients. These clients execute service requests to generate the calculated load. Since the partition and distribution are done during the test runtime, it can handle adynamic set of clients with fluctuating resources. The proposed framework will be able to test a wide range of systems. It is aimed to run system leveltests under laboratory and field test conditions.

Proceedings. Ninth International Workshop on Rapid System Prototyping (Cat. No.98TB100237), 2000

Twelfth Annual IEEE International ASIC/SOC Conference (Cat. No.99TH8454), 2000

In this paper we present the architecture and implementation of our new configurable and scalable... more In this paper we present the architecture and implementation of our new configurable and scalable chip well suited for rapid prototyping of asynchronous designs. A flexible number of arithmetic operators, e.g. 720 add/sub operators for the first chip, are interconnected via a configurable network. For demonstration a DCT algorithm was mapped onto the chip

Der vorliegende Beitrag diskutiert das Nutzungspotential des deterministischen Bussystems FlexRay... more Der vorliegende Beitrag diskutiert das Nutzungspotential des deterministischen Bussystems FlexRay im Automobil. Dabei wird sowohl auf das Konzept einer zeitgesteuerten System- und Knotenarchitektur sowie deren mögliche Umsetzung näher eingegangen. In Verbindung mit dem Standard AUTOSAR und geeigneter Betriebssystemunterstützung lässt sich ein deterministisches Zeitverhalten und dadurch eine erhebliche Verbesserung in der Qualität von Fahrwerkregelsystemen erreichen. Ergänzt wird der Artikel um praktische Erfahrungen bei der Anwendung der aktuellen Entwicklungsumgebung.

This paper describes a methodology for system level design. The starting point is a specification... more This paper describes a methodology for system level design. The starting point is a specification given as standard C program. After a HW/SW-codesign step, design space exploration is performed by examining several versions of the initial design created by means of high-level transformations. Our approach includes an acceleration of the design loop by replacing all tasks of physical design (especially the expensive task of logic synthesis) by a corresponding estimation step. For this, design space exploration can be carried out completely without considering physical design. A complete synthesis process has to be performed once for the only design identified for implementation within the design space exploration phase. The applicability of our methodology is demonstrated by means of an example application, the algorithm for computation of the discrete cosine transformation.

This paper deals with a measure theoretical model for evaluation of e-learning programs. Based on... more This paper deals with a measure theoretical model for evaluation of e-learning programs. Based on methods of general measure theory an evaluation model is developed which can be used for assessment of complex target structures in context of e-learning programs. With the presented rating function target structures can be evaluated by a scoring value which indicates how the targets in sense of a given logical target structure has been reached. A procedure is developed for the estimation of scoring values for target structures based on adapted assessment checklists. 3

Proceedings IEEE Symposium and Workshop on Engineering of Computer-Based Systems, 2000