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Utilization Factor (utilization + factor)
Selected AbstractsAn overlapping task assignment scheme for hierarchical coarse-grain task parallel processingCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 11 2006Akimasa YoshidaArticle first published online: 12 JAN 200 Abstract This paper proposes an overlapping task assignment scheme for the hierarchical coarse-grain task parallel processing on multiprocessor systems. In coarse-grain task parallel processing, the compiler extracts parallelism among coarse-grain tasks automatically and the coarse-grain tasks are assigned to processor clusters at runtime. However, several programs may decrease the processor-cluster utilization factor owing to lack of parallelism inside each coarse-grain task. Therefore, in order to improve the processor-cluster utilization factor, this paper proposes the execution scheme with overlapping task assignment whose dynamic scheduler can assign several coarse-grain tasks to a processor cluster simultaneously. Also, the performance evaluations by simulations and executions on SMP showed that the proposed scheme could reduce the execution time remarkably. Copyright © 2006 John Wiley & Sons, Ltd. [source] A simple method for output voltage control of a three-phase multilevel inverter considering DC voltage fluctuationELECTRICAL ENGINEERING IN JAPAN, Issue 3 2010Kenji Amei Abstract Multilevel inverter circuit generates the stair-like voltage without using transformer and interphase reactor, and it is the circuit which realizes reduction in the harmonics and enlargement of the capacity. In addition, the application of PWM control improves the waveform, and reduces the switching component to the conventional half, and the filter capacity is reduced. In this paper, improvement on the voltage utilization factor and feedback control of output voltage are applied to multilevel inverter circuit. For the DC power supply with the intense fluctuation, it is necessary to construct inverter circuit which can supply stabilized AC voltage. One-chip microcomputer with various functions is used for the control equipment of this circuit, and miniaturization and cost reduction of the control equipment are realized. Here, the control principle and experimental results of this equipment are mainly reported. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 170(3): 40,47, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20906 [source] Examples of fire engineering design for steel members, using a standard curve versus a new parametric curveFIRE AND MATERIALS, Issue 2-4 2004C. R. Barnett Abstract This paper presents examples of the differences that can occur when a standard time-temperature curve and a parametric time-temperature curve are used to determine temperatures likely to be reached by uninsulated and insulated steel members during a fire. For low and moderate structural fire severity situations, determination of the adequacy of a steel member by comparing the temperature reached in a ,design fire' with the limiting temperature based on the member heat sink characteristics, extent of insulation and utilization factor is becoming increasingly common fire engineering design practice. For this it is important to have an accurate and widely applicable parametric fire model as is practicable. The standard time-temperature curve used in the examples is the ISO 834 curve. The two parametric time-temperature curves used in the paper are the Eurocode parametric curve and a recently developed one termed the ,BFD curve'. The latter has been found to fit the results of a wide range of actual fire tests more closely than do existing parametric curves and is mathematically simpler in form. The shape of the BFD curve and the parameters used to define it bear a strong relationship to both the pyrolysis coefficient (R/Avhv0.5) and the opening factor, F02. The curve also models the development of fire without the need for time shifts. It uses a single and relatively simple equation to generate the temperature of both the growth and decay phases of a fire in a building and only three factors are required to derive the curve. These factors are (i) the maximum gas temperature, (ii) the time at which this maximum temperature occurs, and (iii) a shape constant for the curve. If desired, the shape constant can be different on the growth and the decay sides to model a very wide range of natural fire conditions and test results. This paper presents an overview of the background to the BFD curve. It then illustrates its use in a simple fire engineering design application, where the adequacy of a steel beam is checked using the Eurocode parametric curve and the BFD curve to represent the fire. Copyright © 2004 John Wiley & Sons, Ltd. [source] Performance evaluation of an electricity base load engine cogeneration systemINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 9 2010Denilson Boschiero do Espirito Santo Abstract Decentralized electricity production by cogeneration can result in primary energy economy, as these systems operate with a high-energy utilization factor (EUF), producing electricity and recovering energy rejected by the prime mover to meet site thermal demands. Because energy demands in buildings vary with such factors as the hour of the day, level of activity and climatic conditions, cogeneration case studies should consider different system configurations, energy demand profiles and climatic profiles. This paper analyzes an engine cogeneration system as an integrated thermal system by means of a computational simulation program. The simulation takes into account characteristics of the system, characteristics of the pieces of equipment, design choices and parameters, the variability of operating conditions, site energy demand profiles and climatic data to evaluate the performance of the cogeneration plant. Performance evaluation is based on: (i) the EUF, (ii) the exergy efficiency and (iii) primary energy savings analysis. Copyright © 2009 John Wiley & Sons, Ltd. [source] | ||||||||||