Klaus Kabitzsch

A new beacon order adaptation algorithm for IEEE 802.15.4 networks

The new IEEE 802.15.4 standard enables deployment of low-rate low-power personal area networks. It provides a mechanism for adaptation of the protocols duty cycle during runtime. In this paper we propose BOAA, a new algorithm for beacon order adaptation in IEEE 802.15.4 star-topology networks. By observing the communication frequency, the coordinator in such a network determines the required duty cycle and adapts the beacon interval accordingly. Investigations reveal that the algorithm enables power saving with a trade-off according to message delay

Extraction of feature models from formal contexts

For economical reasons, the creation of feature oriented software should include previously created products and should not be done from scratch. To speed up this migration process, feature models have to be generated automatically from existing product variants. This work presents an approach based on formal concept analysis that analyzes incidence matrices containing matching relations as input and creates feature models as output. The resulting feature models describe exactly the given input variants. The introduced novel optimized approach performs this transformation in reasonable time even for large product libraries.

Software Agents in Industry: A Customized Framework in Theory and Praxis

Recently, distributed agents are increasingly adopted in automation control systems, where they are used for monitoring, data collection, fault diagnosis and control. However, existing agent platforms do not always fulfill the requirements of practical automation applications in respect of real-time properties and resource usage. Often, they offer a lot of functionality that is not necessary in automation and leads to significant overhead in respect of design effort and runtime resources. To meet the specific requirements of the automation domain, a resource-efficient agent platform was developed, which relies on established concepts of agent platforms, but modifies and supplements them accordingly. This platform is implemented in Java and in several C++ variants. This paper describes the architecture of the platform and discusses several performance issues. Results of various performance tests are presented in comparison to the established agent platform JADE. Finally, a practical use case is presented, where the platform is utilized to drive a hardware-in-the-loop emulation and testing environment.

Automated Design of Building Automation Systems

The design of large building automation systems (BASs) with thousands of devices is a laborious task with a lot of recurrent works for identical automated rooms. The usage of prefabricated off-the-shelf devices and design patterns simplifies this task nowadays but creates new interoperability problems. As a result, the selection of devices is essential for a good system design but is often limited by a lack of information. This paper introduces a novel automatic design approach for large BASs that covers the device selection, interoperability evaluation, and composition of BASs. It follows a continuous top-down design with different levels of abstraction starting at requirement engineering and ending at a fully developed and industry-spanning BAS design.

Towards Comparison of Deadband Sampling Types

The deadband sampling can be used in networked control systems to reduce the number of triggered events. The purpose of this paper is to define the influence of different factors on the efficiency of deadband sampling. Different deadband criteria, control algorithms and configurations of closed control loops using deadband samplings are compared on the basis of extensive simulations. The control loop performance and the number of triggered events are evaluated simultaneously.

A traffic model for networked devices in the building automation

Traffic models play a decisive part in the performance evaluation and design of communications systems. However, the growing diversification of devices in large networks asks for automated generated traffic models. In this paper, we present a generic device model which is suited for automated generation in the domain of building automation. The traffic is deduced successive for common devices from measurements and simulations using classification of the devices by their traffic behaviour and automated parameterization of the device models

A new protocol for a low power sensor network

This paper proposes a simple protocol for low-power sensor networks with battery-operated sensing devices. The sensors are expected to become active only when certain events in the environment occur. Therefore, a scheme for the application and medium access cycles is developed which avoids common problems of energy loss due to idle actions. Subsequently, the protocol is evaluated according to sensor lifetime. In contrast to common performance analysis, the approach considers the application behavior as a main impact on the sensor lifetime. Capabilities to save energy are derived.

Ontology-based device descriptions and device repository for building automation devices

Device descriptions play an important role in the design and commissioning of modern building automation systems and help reducing the design time and costs. However, all established device descriptions are specialized for certain purposes and suffer from several weaknesses. This hinders a further design automation, which is strongly needed for the more and more complex building automation systems. To overcome these problems, this paper presents novel Ontology-based Device Descriptions (ODDs) along with a layered ontology architecture, a specific ontology view approach with virtual properties, a generic access interface, a triple store-based database backend, and a generic search mask GUI with underlying query generation algorithm. It enables a formal, unified, and extensible specification of building automation devices, ensures their comparability, and facilitates a computer-enabled retrieval, selection, and interoperability evaluation, which is essential for an automated design. The scalability of the approach to several ten thousand devices is demonstrated.

Automatic variation-point identification in function-block-based models

Function-block-based modeling is often used to develop embedded systems, particularly as system variants can be developed rapidly from existing modules. Generative approaches can simplify the handling and development of the resulting high variety of function-block-based models. But they often require the development of new generic models that do not utilize existing ones. Reusing existing models will significantly decrease the effort to apply generative programming. This work introduces an automatic approach to recognize variants in a set of models and identify the variation points and their dependencies within variants. As result it offers automatically generated feature models and ICCL content to regenerate the given variants.

BASont - A modular, adaptive building automation system ontology

Several ontologies exist that model aspects of home or building automation systems for specific use cases. However, no comprehensive approach exists, that models building automation systems in a modular way to be usable in various use cases and tools. The paper proposes the BASont that addresses various use cases over the life cycle of a building automation system from design, to commissioning, to operation, and refurbishment. The use of the BASont is demonstrated for a data retrieval and self-commissioning use case.