Investigation of Phase-wise Voltage Regulator Control Logics for Compensating Voltage Deviations in an Experimental Low-voltage Network

This paper investigates the control logics of an on-load tap-changer (OLTC) transformer by means of an experimental system validation. The experimental low-voltage unbalanced system consists of a decoupled single-phase OLTC transformer, a 75-metre 16 mm2 cable, a controllable single-phase resistive load and an electric vehicle, which has the vehicle-to-grid function. Three control logics of the OLTC transformer are described in the study. The three control logics are classified based on their control objectives and control inputs, which include network currents and voltages, and can be measured either locally or remotely. To evaluate and compare the control performances of the three control logics, all the tests use the same loading profiles. The experimental results indicate that the modified line compensation control can regulate voltage in a safe band in the case of various load and generation conditions

Knowledge sharing by information retrieval in the semantic web

Effective and efficient information retrieval, knowledge sharing and combining has become an essential part of more and more professional tasks and work flows in different kinds of projects. Our aim is to investigate the use of emerging Semantic Web technologies, tools, and standards in the support of effective information retrieval in real multi-disciplinary activities, such as innovative product design. This paper presents an approach to knowledge sharing and information support that has been developed and adopted, the information system architecture that is being developed to test both this approach, and the Semantic Web techniques that are used in its implementation, some early results, and a discussion of related work in information systems and Semantic Web techniques and tools

Informationsmanagement auf der Basis von Semantic-Web Techniken oder ein Google für Entwickler

Information retrieval often suffers from the lack of suitable search tools or the query complexity. The search of some concrete information on the base of file names or the coincidental occurrence of key words in files is little helpful because the obtainable matches are too much subject to chance. Therefore an effective search must be based on the semantic interpretation of the query and additionally casts of the query into the context of an application domain. Here the development of the search machine prototype WIDE is presented, which builds up the query interpretation on Semantic Web techniques. The search machine can be configured for application domains and is able to map a query to different data sources in parallel. The search machine processes the retrieved results graphically and associates the concepts used in the Query with thematically related concepts. The search machine can be used to retrieve text documents or test bed results of experiments archived in ASAMODS data source

Retrieval analysis of alumina ceramic-on-ceramic bearing couples

BACKGROUND AND PURPOSE: Ceramic-on-ceramic (CoC) bearings have been in use in total hip replacement (THR) for more than 40 years, with excellent long-term survivorship. Although there have been several simulator studies describing the performance of these joints, there have only been a few retrieval analyses. The aim of this study was to investigate the wear patterns, the surface properties, and friction and lubrication regimes of explanted first-generation alumina bearings. MATERIALS AND METHODS: We studied 9 explanted CoC bearings from Autophor THRs that were revised for aseptic loosening after a mean of 16 (range 7–19) years. The 3D surface roughness profiles of the femoral heads and acetabular cups (Srms, Sa, and Ssk) were measured to determine the microscopic wear. The bearings were imaged using an atomic-force microscope in contact mode, to produce a topographical map of the surfaces of the femoral heads. Friction tests were performed on the bearing couples to determine the lubrication regime under which they were operating during the walking cycle. The diametral clearances were also measured. RESULTS: 3 femoral heads showed stripe wear and the remaining 6 bearings showed minimal wear. The femoral heads with stripe wear had significantly higher surface roughness than the minimally worn bearings (0.645 vs. 0.289, p = 0.04). High diametral clearances, higher than expected friction, and mixed/boundary lubrication regimes prevailed in these retrieved bearings. INTERPRETATION: Despite the less than ideal tribological factors, these first-generation CoC bearings still showed minimal wear in the long term compared to previous retrieval analyses