• 정보통신설비학회논문지
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• 제10권1호
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• pp.33-39
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• 2011

This paper considers a performance analysis of set-top box (STB) power saving schemes. STB converts the signal into content which is then displayed on the television (TV) screen, and there are typically two operation modes: on mode and stand-by mode. The total energy consumption (TEC), a typical measure of power consumption of STB, is defined by the sum of power consumption in each mode. Recently there are some works of STB power saving schemes that transit STB operation modes efficiently, and the mode transition time point of those schemes can be different. Thus it is required to develop a performance evaluation method that reflects mode transition time points of each scheme to get TEC correctly. This paper proposes a performance evaluation method for STB power consumption using Poisson process to consider the mode transition time point. By modeling STB mode transitions as events of Poisson process, the average time duration of STB mode is computed and accordingly the effect of power saving is evaluated. The performance evaluation result shows that the proposed method achieves 1 to 19% improvement in power consumption compared with a conventional performance evaluation method.

• 한국가스학회지
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• 제23권5호
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• pp.8-14
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• 2019

국내 도시가스 보급률은 크게 성장했지만, 국내 가스계량기 계량·안전점검·요금 분야는 아직 서비스 초기방식에서 벗어나지 못하고 있다. 스마트가스미터에 관한 개발과 연구가 활발히 이루어지고 있지만 스마트가스미터의 도입에는 신뢰성과 안전성을 검증할 수 있는 합리적인 성능평가 방안과 기준이 필요하다. 본 논문은 스마트가스미터의 성능을 시험하기 위한 성능시험 시작품을 제작하고 시작품의 실증 운용을 통해 성능평가 방안을 최적화하여 국내에 스마트가스미터가 원활하게 확대/보급될 수 있도록 하는 것을 목적으로 한다.

• 한국지진공학회논문집
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• 제23권1호
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• pp.71-82
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• 2019

Most school buildings consist of reinforced concrete (RC) moment frames with masonry infills. The longitudinal direction frames of those school buildings are relatively weak due to the short-column effects caused by the partial masonry infills and need to be evaluated carefully. In 'Manual for Seismic Performance Evaluation and Retrofit of School Facilities' published in 2018, response modification factor of 2.5 is applied to non-seismic RC moment frames with partial masonry infills, but sufficient verification of the factor has not been reported yet. Therefore, this study conducted seismic performance evaluation of planar RC moment frames with partial masonry infills in accordance with both linear analysis and nonlinear static analysis procedures presented in the manual. The evaluation results from the different procedures are compared in terms of assessed performance levels and number of members not meeting target performance objectives. Finally, appropriate response modification factors are proposed with respect to a shear-controlled column ratio.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1024-1027
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• 2005

This paper describes the performance index of mobile robot and development of testbed which is used to evaluate the index. The developed testbed has rectangular structure similar to a living room of home. It is semi-automation testbed system for evaluation of cleaning performance index. This system is composed with scattering and cleaning equipment of test materials, equipment rifting of objects in inner space and sides itself, vision processing system. To be consistent of performance evaluation of cleaning robot, we make use of camera in this system for the sake of measurement of robot s mobility, path and suction quantity.

• 전기학회논문지
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• 제59권12호
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• pp.2179-2189
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• 2010

This paper deals with analytical techniques for performance evaluation of small scaled wind power generator with outer permanent magnet rotor. In part (1), using transfer relations theorem, magnetic field distribution characteristics by PM and armature reaction field are derived. Moreover, electrical parameters such as back-EMF, inductance and resistance are calculated from the obtained field characteristic equations. The proposed analytical techniques are validated by nonlinear finite element method using commercial software 'Maxwell' and performance experiments of the manufactured generator. In part (2), generating characteristics analysis such as constant speed characteristics and constant resistive load characteristics, and performance evaluation according to variation of wind speed will be accomplished using the derived electrical parameters.

• 산업공학
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• 제9권2호
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• pp.191-202
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• 1996

A variety of approaches on performance evaluation modeling have appeared in the technical literature for flexible manufacturing systems(FMS) which can be evaluated only through computer simulation. This study represents a comparative approach for FMS performance evaluation modeling based on reliability, availability and maintainability, and life cycle cost. The methodology proposed in this research includes the following three-step generative approaches. First, a static model to find the initial system configuration is considered under the assumption that the system availability is given as one (failure and maintenance are not considered), and in second step, a stochastic simulation is proposed to serve as a performance evaluation model for FMS with stochastic failure and repair time. In the last step, we developed a simulation modeling using a simulator, FACTOR/AIM to consider a variety of performance factors and dynamic behavior of FMS. Also the applicability and validity of the proposed approaches has been tested and compared through the results of a sample problem using computer programs and procedures developed in each step.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1143-1147
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• 2010

The verification of the seismic performance of many urban railway bridges will be done or is done by the regulations of "Seismic Performance Evaluation Methods(Tips) of Existing Bridges" developed by KISTEC in 2004. This present process may involve some of the issues such as the unreflecting of the characteristics of the urban railway bridge and the appearance of ductility-based seismic design method. In this paper, the new and improved seismic performance evaluation system is proposed.

• Management Science and Financial Engineering
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• 제11권3호
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• pp.19-45
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• 2005

Collaborative filtering is one of the most common methods that e-commerce sites and Internet information services use to personalize recommendations. Collaborative filtering has the advantage of being able to use even sparse evaluation data to predict preference scores for new products. To date, however, no in-depth investigation has been conducted on how the data sparsity effect in customers' evaluation data affects collaborative filtering-based recommendation performance. In this study, we analyzed the sparsity effect and used a hybrid method based on customers' evaluations and purchases collected from an online bookstore. Results indicated that recommendation performance decreased monotonically as sparsity increased, and that performance was more sensitive to sparsity in evaluation data rather than in purchase data. Results also indicated that the hybrid use of two different types of data (customers' evaluations and purchases) helped to improve the recommendation performance when evaluation data were highly sparse.

• 한국수소및신에너지학회논문집
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• 제22권6호
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• pp.810-818
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• 2011

This paper analyzed the suitability about the isolation performance criteria which was based on human impedance and effect of current in IEC 60479-1 on the safety of human being was examined. The method of evaluation by megger and DC voltmeter was analyzed. The differences of isolation performance according to design of high-voltage system were analyzed. The factors which affect the insulation performance were analyzed for HFCV, EV, HEV, etc. through analysis of the isolation performance evaluation method. Finally, design for improved isolation performance was proposed.

• 대한안전경영과학회지
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• 제9권4호
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• pp.49-56
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• 2007

It is known that human factors account for 80 percent of all railway accidents. To reduce human errors must be the most efficient shortcut to railway safety. For public transportation employees like railway, the more delicate safety management should be executed in individual level. However, there are rarely efforts to improve safety performance of workers who are the subject operating the railway system. This paper develops a hierarchy model to evaluate the human safety performance in railway industry. To evaluate the model, AHP (Analytic Hierarchy Process) methodology is adopted. The hierarchy model is composed of four levels which are objective, two criteria, specific factors of criteria, and rating scales. In addition, since employees for evaluation are over 10, the pairwise comparisons for rating scales are carried out by the absolute measurement. We explore the applicability of AHP to the performance evaluation of railway safety workers by an example and also investigate the changes of alternatives that are railway employees according to the changes of human characteristic which is one of criteria.