• 한국항해학회지
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• 제22권4호
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• pp.31-36
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• 1998

The whistle is a very important information source for the safety navigation under foggy weather. But navigator has no concern about this, because it must be achived by human hearing sense and considered as a vague signal. If the range and relative bearing of signal source can be detected automatically, it would be very useful system for preventing marine casualties making a lot of economic loss and environment pollution. Before the algorithm of 2-dimensional sound source tracking system was reported. This paper describes the method that can obtain the time lag between three signals and the theory of cross-correlation analysis and subtraction method for cauculating the time lag by using the digital signal data sequences. And a series of experiments were carried out for various position of sound source in the range from 200cm to 530cm. As a result, we have recognized that sound source tracking system is possible to the sea field with improvement of position error.

• 대한전기학회논문지
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• 제32권4호
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• pp.145-154
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• 1983

This paper presents a new method for optimal real and reactive power dispatch for the economic operation of a power system. Unlike the usual approach of minimizing the transmission loss, this method minimizes the total production cost not only for the real power optimization problem, but also for the reactive power optimization. The control variables are real power generation of units for real power optimization, and reactive power optimization. The constraints are the operating limits on these control variables and the limits on the bus voltages. Methematical models are developed to represent the sensitivity relationships between dependent and control variables for both real and reactive power optimization modules, and thus eliminate the use of B-coefficients. In order to handle many functional inequality constraints, a modified version of the gradient projection method is developed for optimization procedure, and has shown a remarkable advantage in computation efficiency.

• 전기학회논문지P
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• 제54권2호
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• pp.101-107
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• 2005

The reduced power quality due to some of disturbances on power system has great influence on the efficient and life of load for bad with serious economic loss. The response of load about disturbance needs to analysis quantitatively in detail to improve load characteristics. In this research, a power supply device is developed to supply disturbed power similar to that of power system. The developed device can output a voltage and frequency from 180[V] to 240[V], 55[Hz] to 65[Hz] respectively. The most outstanding feature of this device is a function to be performed steady and dynamic state characteristic experiment on load or appliances. Also, this device is designed to include high accuracy ouput and simple measurement.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.403-405
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• 1999

Power transformers have a tendency of ultra-high voltage and huge capacity as power demand increases day after day. Therefore, the fault by insulation destruction gives rise to large area of power failure in huge capacity transformers. On-line predictive diagnostics is very important In power transformers because of economic loss and its spreading effect. Hence, this study presents experiments of partial discharge method using ultrasonic sensor in order to confirm the possibility of ultrasonic sensor in power transformers. It carries out the experiments of measuring delay time between ultrasonic sensor and transducer, sensitiities by temperature change of oil and by barriers inside transformers. It is also Included wave analysis by ultrasonic sensor for needle-plate electrode powered on through high-voltage equipments.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1903-1905
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• 2000

Power transformers have a tendency of ultra-high voltage capacity as power demand increases day after day KEPCO also will have plan to supply transmission power from 345KV to 765KV in the early of 2000. Therefore, the fault by insulation destruction gives rise to large area of power failure in huge capacity transformers. On-line predictive diagnostics is very important in power transformers because of economic loss and its spreading effect. This study presents the algorithm for transformer oil analysis used KEPCO code, IEC code, gas pattern method and Dornenburg & Roger Ratio method. We also describe the MMI display of expert system programmed by Element Expert Tool(Neuron Data Inc.).

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 춘계 학술논문 발표대회
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• pp.109-110
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• 2015

Estimation of rebar quantity may be used as an index to evaluate the economic feasibility of structural designs. However, when using the software to estimate the rebar quantity, there may be some limitations such as data loss caused by human errors and estimation delays caused by increased input time, since the information on arrangement of rebar is inserted manually. To solve the problems of such quantity estimation software, it is necessary to develop a method on automatic input/output of structural design information for quantity estimation and an algorithm for accurate estimation of rebar quantity. The purpose of this study is to improve the existing rebar quantity estimation by connecting with the database on information related to rebar estimation and the algorithm for rebar estimation, in order to develop an algorithm to estimate an accurate, net rebar quantity. The study result can be used as basic data for development of software for efficient structural designs and automatic framework estimation of buildings.

• BMB Reports
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• 제51권4호
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• pp.167-173
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• 2018

Experimental results obtained from research using only one sex are sometimes extrapolated to both sexes without thorough justification. However, this might cause enormous economic loss and unintended fatalities. Between years 1997 and 2000, the US Food and Drug Administration suspended ten prescription drugs producing severe adverse effects on the market. Eight of the ten drugs caused greater health risks in women. Serious male biases in basic, preclinical, and clinical research were the main reason for the problem. This mini-review will describe why and how funding organizations such as the European Commission, the Canadian Institutes of Health Research, and the US National Institutes of Health have tried to influence researchers to integrate sex/gender not only in clinical research, but also in basic and preclinical research. Editorial policies of prominent journals for sex-specific reporting will also be introduced, and some considerations in integrating sex as a biological variable will be pointed out. To produce precise and reproducible results applicable for both men and women, sex should be considered as an important biological variable from basic and preclinical research.

• 한국정보시스템학회지:정보시스템연구
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• 제15권1호
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• pp.215-238
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• 2006

The purpose of this study is to develop the measures of the perceived risks involved in e-commerce. To do this, we first review the literature and examine the sub-constructs of the perceived risks. The risks classified are economic risk, product performance risk, social risk, technology/time loss risk, and privacy risk. Based on these findings, we identify the appropriate items for assessing these various risks. Then, we evaluate, basically using a structural equation model, the important several attributes of the measurs such as various validities and reliability. This study finally provides the rigorously tested measuring instruments of the construct of the perceived risks.

• 한국시뮬레이션학회논문지
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• 제6권1호
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• pp.97-108
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• 1997

For the purpose of decreasing economic loss from the traffic jam, a car route guidance system efficiently utilizing the existing roads has attracted a great deal of attention. In this paper, the search algorithm for optimal path and alternative paths, which is the main function of a car route guidance system, was presented using evolution program. Search efficiency was promoted by changing the population size of path individuals in each generation, applying the concept of age and lifetime to path individuals. Through simulation on the virtual road-traffic network consisting of 100 nodes with various turn constraints and traffic volumes, not only the optimal path with the minimal cost was obtained, avoiding turn constraints and traffic congestion, but also alternative paths with similar costs and acceptable difference was acquired, compared with optimal path.

• 한국건축시공학회지
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• 제2권4호
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• pp.137-144
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• 2002

In the modern age. Building is getting higher and larger according to owner and social demands. Now when we are facing the need of the cost down and the reduction of economic loss. In this paper, the characteristics of the present conditions of site management were investigated with the field survey. And The Purpose of this study is to suggest the rational plans of construction planning in site management. The method of site management. however depends on experience of a construction manager. in order to solve this situation, it is necessary to create a method of site management that is adequate for the condition of construction. By cultivating excellent sub contractors, we can expect precise construction with a few experts. improvement in qualify of construction from standardization, computerization of each process. And the expectancies of this paper are that it can be used as efficient data for improvement of system to systematize site management work in Korea.