Ein Multi-Agentensystem für die modellbasierte Echtzeit-Fehlerdiagnose

Real-time AI systems, among them multiagent systems, are gaining importance in complex technical applications. This paper presents VEX, an ambitious multiagent system for model-based real-time fault diagnosis in modular production systems. The architecture comprises several process agents, a simulation agent and a user agent. We discuss the most interesting characteristics of this real-time AI architecture. As implementation examples we present the multi-DSP core of the simulation agent, the client-server communication protocol for the process agents and the user agent’s graphical interface.     

Computed tomographic angiography of the thoracic vessels: the method, initial experience and outlook for its use

The paper presents the data available in the literature on computed tomographic angiography and the first experience with it to study thoracic vessels. It details the principles of spiral computed tomography and CT angiography. Practical aspects of their implementation, as well as basic concepts are outlined. It is concluded that CT angiography is promising in studying thoracic vessels in various abnormalities.     

Zur Bestimmung der Einflußbereiche bei Beeinflussungsuntersuchungen

This paper deals with the global basis of evaluation in different cases of electrical interference due to Austrian standards. Conditions are explained to harmonize standards in case of inductive interference, electrostatic influence and resistive interference in connection to probability factors. Relevant notions as zone of exposure, area of protection and restricted area are explained to create optimal strategies of planning.     

Assessment of a radioactive waste disposal site at Enewetak Atoll

The 43 nuclear tests conducted at Enewetak Atoll by the United States between 1948 and 1958 produced close-in fallout that contaminated the islands and lagoon of the atoll with radioactive fission and activation products, and unfissioned nuclear fuel. In 1972, the U.S. government announced that it would conduct a cleanup and restoration operation to return the atoll to the Enewetak people. The radiological cleanup began in 1977 and lasted to 1980 and focused on reducing the concentration of the transuranium elements (238,239,240Pu and 241Am = TRU) in soils on some of the islands that might eventually be used for residence or for subsistence agricultural. The cleanup plan called for relocating soil and some other contaminated debris to Runit Island on the eastern perimeter of the Atoll. Some of the contaminated soil was mixed with cement and the mixture placed below the water level in the Cactus Crater that was formed by a nuclear explosion in 1958. The remainder of the contaminated material was mixed with concrete and placed above ground over the crater in the shape of a dome. A concrete cap was constructed over the dome of soil. Concern has been expressed by the people of Enewetak and by others over the possible aquatic impacts from the radionuclides entombed in the crater. A National Academy of Sciences committee examined the dome and concluded that the containment structure and its contents present no credible health hazard to the people of Enewetak, either now or in the future. The committee suggested that "at least part of the radioactivity contained in the structure is available for transport to the groundwater and subsequently to the lagoon and it is important to determine whether this pathway may be a significant one." Therefore, a surveillance program was started in 1980, in conjunction with other research efforts, to study the radionuclides in samples of fish, groundwater, and lagoon seawater. Our data and conclusions support the findings suggested by the National Academy committee over a decade ago in that any assumption of rapid remobilization of all or any of the dome's transuranics or other radionuclides is an extreme one. Any fear that this structure contains amounts of activity whose release would cause damage to the environment that will result in greater effect on human health is unfounded.     

Verteilte Flickermessungen in Windparks

Wind power stations in windfarms connected to the power system can disturb the power quality. Effects like pole-reconnections, shadowing-effects as well as wind squalls will result in power fluctuations. So voltage fluctuations and flicker effects will occur. We present results of field measurements, carried out on windfarms in Germany in April 1998.