• 설비공학논문집
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• 제16권6호
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• pp.556-565
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• 2004

We have experimented an actual solar water heating system acquiring real data for one year period. On the basis of the operation data, it is necessary to predict the system performance such as collector efficiency and solar fraction, and to analyze the economical efficiency for system optimal design. To estimate the performance of actual systems through simulation, valid modelling for components consisting of the system should be accompanied. The present study is focused on the modelling for load patterns and operating control conditions. We proposed two load models: concentration model which gathers real loads as a meaningful group and distribution model which disperses real loads with time. If grouping of the load distribution is suitable, the predicted values by the concentration model approaches to those by the distribution model close to actual load pattern apparently. As a result, both of them are in good agreement with those by experiment.

• 통상정보연구
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• 제5권2호
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• pp.207-225
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• 2003

The purpose of this study is to examine the legal aspects on the formation of international contract in electronic commerce. The findings could be summarized as follows. rug, the contract doctrine of the contract formation by electronic data message, time of dispatch and receipt of data message, error in electronic communication, contract form and electronic signature could be supported or protected by the existing contract doctrine. Second, In relation to the contract formation arranged by electronic agents, the established contract doctrine provides no clear answer to the question whether changes provided by the interaction of electronic agents are enforceable. The enforceability question is left to future legislation. Finally, It is necessary that a significant level of formality together with the disclosure on the contract formality by certain act be conveyed 10 a potential buyer so that the buyer is impressed that the contact by the certain act could be valid.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 봄 학술발표회 논문집
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• pp.467-474
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• 2000

The application of Terzaghi's theory of consolidation for analysing the settlement of multi-layered soils is not strictly valid because the theory involves an assumption that the soil is homogeneous. The settlement of stratified soils with confined aquifer can be analysed using numerical techniques whereby the governing differential equation is replaced by 2-dimensional finite difference approximations. The problems of discontinuous layer interface are very important in the algorithm and programming for the analysis of multi-layered consolidation using a numerical analysis, finite difference method(F.D.M.). Better results can be obtained by the process for discontinuous layer interface, since it can help consolidation analysis to model the actual ground The purpose of this paper provides an efficient computer algorithm based on numerical analysis using finite difference method(F.D.M) which account for multi-layered soils with confined aquifer to determine the degree of consolidation and excess pore pressures relative to time and positions more realistically.

• 대한음성학회지:말소리
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• 제51호
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• pp.17-37
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• 2004

The purpose of this dissertation is to make the general korean speakers to learn the standard pronunciations. But it is in existence that the obstructions of the command of the standard pronunciations. They are the mistake in the education course on the korean pronunciations, the teacher's capability and the mass communications's duplicity. To overcome this obstructions, we must concentrate our efforts on the propagation of the standard pronunciations. To propagate of the standard pronunciations we can take a several method. These are the presentation of the pronunciation mistakes, audio-visual teaching, the presentation of the pronunciation principles and the use of the korean dictionary. The standard pronunciations are different from the pronunciations of the general korean speakers in many respects. So we can't make an accurate estimate of the pronunciation's changes. No one knows what will happen in the future about the korean pronunciations. But we must teach the standard pronunciations to the general korean speakers. The standard pronunciations are offically valid in the present time.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2004년도 춘계공동학술대회 논문집
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• pp.96-101
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• 2004

In this paper, we propose an effective cut generation method based on the Chvatal-Gomory procedure for a variable-capacity (0,1)-Knapsack problem, which is the same problem as the ordinary binary knapsack problem except that a binary capacity variable is newly introduced. We first derive a class of valid inequalities for the problem using Chvatal-Gomory procedure, then analyze the associated separation problem. Based on the results, we show that there exists a pseudopolynomial time algorithm to solve the separation problem. Preliminary computational results are presented which show the effectiveness of the proposed cut generation method.

• 한국태양에너지학회 논문집
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• 제21권4호
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• pp.21-28
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• 2001

It is a time since sustainable architecture become a main issue of design concept in 21C. However, it is necessary to develope the tool estimating energy loads and uses in our architectural conditions for energy saving design. This study aims to develope the E-Load program to predict heat and cooling loads of houses. The program is developed by modified bin methods derived from ASHRAE TC 4.7. It consists of 4 divisions such as files, data inputs, energy load estimations and output options. The main processes of energy load estimations are based on ASHRAE fundamentals. The developed E-Load program is a easy and valid tool to predict heat and cooling loads of buildings.

• 전기학회논문지
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• 제67권10호
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• pp.1271-1277
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• 2018

This paper deals with a voltage sag assessment based on a voltage monitoring program. The voltage sag performance at a specific site can be evaluated by analyzing voltage monitoring data recorded for a long time period. Although an assessment based on voltage monitoring is an effective way to understand voltage sag performance at a measurement site, the statistical confidence of voltage sag frequency estimation heavily depends on the length of monitoring period and the number of recorded events. Short monitoring period and insufficient recorded data can not provide a reliable assessment result. This paper proposes a compensation assessment method by combining a computer simulation approach for in case that monitoring period and data are not enough for a valid assessment.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.684_685
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• 2009

A digital sampling algorithm that uses a two high resolution integrating Voltmeters which are synchronized by Phase Lock Loop (PLL) time clock for accurately measuring the parameters, active and reactive power, for sinusoidal power measurements is presented. The PLL technique provides high precision measurements, root mean square (rms), phase and complex voltage ratio, of the AC signal. The system has been designed to be used at the Korean Research Institute of Standards and Science (KRISS) as a reference power standard for electrical power calibrations. The test results have shown that the accuracy of the measurements is better than $10 {\mu}W/VA$ and the level of uncertainty is valid for the power factor range zero to 1 for both lead and lag conditions. The system is fully automated and allows power measurements and calibration of high precision wattmeters and power calibrators at the main power frequencies 50 and 60 Hz.

• 소음진동
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• 제11권2호
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• pp.292-300
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• 2001

This research is concerned with the validation of the modeling technique and controller design for slewing beam structures. When cantilever beam rotates about axes perpendicular to the undeformed beam's longitudinal axis, it experiences inertial loading. Hence, the beam vibrates from the initial stage of slewing. In this paper, the analytical model for a single slewing flexible beam with surface bonded piezoelectric sensor and actuator is developed using the Hamilton's principle with discretization by the assumed mode method. Comparisons with the theoretical model are made based upon the frequency responses and time responses. A new factor called the coupling coefficient is introduced to incorporate the discrepancies between the theoretical and experimental results. The slewing is achieved by applying the PID control, which is found to be less sensitive to vibrations. The vibrations are controlled by PPF controller, which is found to be effective in suppressing residual vibrations after slewing. The vibrations occurred during slewing is difficult to control because the piezoceramic actuator is not powerful enough to overcome inertial loadings.

• Animal Systematics, Evolution and Diversity
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• 제33권4호
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• pp.267-273
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• 2017

The opossum shrimp, Siriella Dana, 1850 belongs to the family Mysidae Haworth, 1825. It is the genus of an enormous number of species with frequent morphological variations comprising 84 valid species to date. Among the species, Siriella trispina Ii, 1964 has been recorded from the Yellow Sea and the East China Sea is reported from Korean water for the first time. Siriella trispina is characterized by its exceedingly elongated 5th pair of thoracopods, the spines on the inner ventral margin of the uropodal endopod armed with secondary spinules, and 4-5 pairs of spines on the base of the telson. In the present study, we describe Korean specimens of the species in detail with photographs and illustrations. Siriella trispina is the 8th Siriella species found in Korean fauna.