Distribution system simulator

In a series of tests performed under the Department of Energy auspices, power line carrier propagation was observed to be anomalous under certain circumstances. To investigate the cause, a distribution system simulator was constructed. The simulator was a physical simulator that accurately represented the distribution system from below power frequency to above 50 kHz. Effects such as phase-to-phase coupling and skin effect were modeled. Construction details of the simulator, and experimental results from its use are presented

Pembinaan konstruk instrumen penilaian pasca penghunian untuk perumahan bertingkat yang dibina menggunakan kaedah Sistem Binaan Berindustri (IBS)

Post Occupancy Evaluation (POE) is an activity of the building evaluation process with a focus on quality, operational performance and satisfaction of the occupants. The POE is important to evaluate completed and occupied buildings to identify weaknesses and potential for future improvement. To date, there have been various variations of POE instruments and tools to evaluate occupied buildings. However, the POE instrument for assessing high-rise housing constructed using the industrialized building system (IBS) method has not been developed specifically. In this regard, this study aims to discuss the construction of an effective POE instrument to measure the quality and performance of high-rise housing built using the IBS method. For this purpose, the 3 round Delphi method was adapted by involving 15 experts selected based on their background and experience related to IBS. The results of a three-round Delphi study found that 33 out of all sub-constructs were dropped because of low mean scores (<4.2 in two rounds) while 75 sub-constructs were identified as final items. The results of the Delphi study also found that all 10 constructs were 1) Spatial; 2) Design and aesthetics; 3) Physical; 4) Building materials; 5) Quality of work; 6) Comfort and well-being; 7) Environment and health; 8) Maintenance; 9) Value and 10) Cost is the most significant construct for developing PPP instruments. Accordingly, an effective Post-Occupancy Assessment Instrument for measuring the quality, performance and value of a home built using the IBS method should include all of these constructs

Time-Scale Domain Characterization of Time-Varying Ultrawideband Infostation Channel

The time-scale domain geometrical-based method for the characterization of the time varying ultrawideband (UWB) channel typical of an infostation channel is presented. Compared to methods that use Doppler shift as a measure of time-variation in the channel this model provides a more reliable measure of frequency dispersion caused by terminal mobility in the UWB infostation channel. Particularly, it offers carrier frequency independent method of computing wideband channel responses and parameters which are important for ultrawideband systems. Results show that the frequency dispersion of the channel depends on the frequency and not on the choice of bandwidth. And time dispersion depends on bandwidth and not on the frequency. It is also shown that for time-varying UWB, frame length defined over the coherence time obtained with reference to the carrier frequency results in an error margin which can be reduced by using the coherence time defined with respect to the maximum frequency in a given frequency band. And the estimation of the frequency offset using the time-scale domain (wideband) model presented here (especially in the case of multiband UWB frequency synchronization) is more accurate than using frequency offset estimate obtained from narrowband models