• Korean Journal of Construction Engineering and Management
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• v.7 no.5
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• pp.177-190
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• 2006

Construction projects are facing delay problems. Delays in construction have been immense effect on performance or satisfactory delivery of the project. Delays have been causing project cost overrun as well as it is a source of dispute hence damaging the relationship between the project participants. The purpose of this study was to explore the causes of delay risk through a field survey study. Data were collected from construction professionals working in owner, consultant and contractor organizations. All together 208 questionnaire instruments were used and analyzed by employing statistical tools (SPSS computer program). 19 delay factors were identified by this study, out of which following factors were critical: Frequent interruptions from public (local people, pressure group etc.), changed site condition, failure to provide required construction site, unrealistic project time estimation and design errors.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.947-951
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• 2010

본 연구는 강우시 A 공업단지와 B 농공단지의 공업지역에서 통계적인 오염물질 농도와 오염물질 특성을 찾아내기 위하여 모니터링 및 분석을 수행하였으며, 강우유출수 조사방법에 따른 원단위 산정을 위하여 유량가중평균농도(EMC)산정, 강우계급별 유량가중평균농도를 산정하였으며, 공업지역의 대표 유량가중평균농도(EMCz) 산정, 유출율을 산정하였으며, 앞에 산정한 자료를 이용하여 선정한 공업지역 원단위를 산정하여 기존 원단위 값과 비교분석 하였다. 이렇게 산출된 자료는 공업지역 비점오염원 최적관리를 위한 과학적 근거자료 제공 및 기초자료서의 활용, 모니터링을 통한 공업지역의 비점오염원의 관리대책 및 낙동강 수질개선을 위한 정책자료에 관한 기초자료 제공, 국내 실정에 부합하는 최적 비점오염원 저감시설의 설치를 위한 기초자료로 활용될 수 있을 것이다.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09c
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• pp.86-95
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• 2010

Ground movements during tunnelling have the potential for major impact on nearby buildings, utilities and streets. The impacts on buildings are assessed by linking the magnitude of ground loss at the source of ground loss around tunnel to the lateral and vertical displacements on the ground surface, and then to the lateral strain and angular distortion, and resulting damage in the building. To prevent or mitigate the impacts on nearby buildings, it is important to understand the whole mechanism from tunnelling to building damage. This paper discusses tunneling-induced ground movements and their impacts on nearby buildings, including the importance of the soil-structure interactions. In addition, a building damage criterion, which is based on the state of strain, is presented and discussed in detail and the overall damage assessment procedure is provided for the estimation of tunnelling-induced building damage considering the effect of soil-structure interaction.

• KSBB Journal
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• v.8 no.3
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• pp.272-281
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• 1993

State varibles were estimated for fermentations of K. marxianus under various dilution rates and dissolved oxygen concentrations. The number of elementary reaction stoichiometry with fixed coefficients was determined by singular variable decomposition. Stoichiometry with feasible physical meaning was obtained by target factor analysis. States of fermentations were estimated by linear quadratic programming. The process conditions of single cell production to maximize carbon source consumption were suggested.

• Journal of Communications and Networks
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• v.18 no.1
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• pp.19-26
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• 2016

In this paper, the performance of dual-hop multi-relay maximum ratio transmission (MRT) over Rayleigh flat fading channels is studied with both conventional (all relays participate the transmission) and opportunistic (best relay is selected to maximize the received signal-to-noise ratio (SNR)) relaying. Performance analysis starts with the derivation of the probability density function, cumulative distribution function and moment generating function of the SNR. Then, both approximate and asymptotic expressions of symbol error rate (SER) and outage probability are derived for arbitrary numbers of antennas and relays. With the help of asymptotic SER and outage probability, diversity and array gains are obtained. In addition, impact of imperfect channel estimations is investigated and optimum power allocation factors for source and relay are calculated. Our analytical findings are validated by numerical examples which indicate that multi-relay MRT can be a low complexity and reliable option in cooperative networks.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.152-155
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• 2000

PWM inverter-fed traction motor is able to occur problems by additive transient surge stress and harmonic loss in contrast with motor driven by 60Hz sine wave alternating source. Therefore in this paper, test method and standard of existed already were investigate, "thermal + electric" complex degradation test that considered additive degradation occurred by inverter drive carried out in order to obtain insulation reliability of traction motor driven by inverter. It seems that this test method confers large value of application at reliability estimation which the subject of complete motor not windings sample from now on.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04a
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• pp.28-30
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• 2003

DVR은 아날로그(analog) 테이프 레코더(tape recorder)에 비해 여러 가지 장점을 가지고 있어 빠른 속도로 아날로그 테이프 레코더를 대치하고 있다［1］. 지금까지 대부분의 DVR시스템은 MS사의 윈도우즈 (MS-windows)애 기반하여 개발되었으나 MS윈도우즈 운영체제의 비공개 소스 코드(source code)로 인해 효율적인 시스템을 개발하기 어려운 문제점이 있다. 이에 본 논문에서는 운영체제의 코드가 오픈 되어있어 누구나 원하는 소프트웨어를 개발할 수 있는 리눅스(Linux) 운영체제를 기반으로 한 DVR시스템의 통신 모듈을 설계한다. 또한 본 논문에서는 리눅스 운영체제의 스케쥴링에 의한 실시간 프로그램의 부하를 측정하고, 본 논문에서 구현한 통신 모듈을 사용하여 프로세스의 개수에 따른 DVR시스템의 성능을 측정하였다. 측정 결과 구현한 통신 모듈은 20Mbps이상의 전송 속도로 수행되는 것으로 나타났다.

• Economic and Environmental Geology
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• v.28 no.5
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• pp.487-491
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• 1995

The multipulse model of linear predictive coding (LPC), which has been successfully used for compressing of speech signals into an impulse excitation, is here applied to seismic data which contains multiples. Multiples are happened by successive reflection between layers and make the seismic interpretation difficult In this paper, the author applied the enhanced multipulse method to seismic traces to compress source-wavelets into spikes, and to eliminate/reduce multiples. The enhanced multipulse method which was applied to seismic traces extracted the amplitudes and locations of reflectivity function, which depicts the subsurface configuration, by iterative computation of autoregressive (AR) estimation method.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.1
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• pp.42-47
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• 2014

The use of BLDC motor in Vehicle and industrial field, it is operated by continuous and intermittent driving. When the intermittent driving is occurred by the rise and fall of temperature repeatedly, it was represented by different characteristics in case of continuous driving. So, it is very important that heat source estimation according to the duty ratio. In this paper, temperature characteristics according to the operating method of BLDCM was calculated by using the thermal equivalent circuit, and the validity of the study was demonstrated as compared to the calculated and experimental results.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2009.06a
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• pp.496-497
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• 2009

This paper describes about the realization of a remote RF sensor system and its applications. RF Sensor System was designed and realized on DSP over the range of high frequency such as about 200[KHz]. It should be "wireless", "implantable" and "batteryless". Futhermore, the system should be consist of passive components such as R, Land C. The measurement was given using the inductive coupling principle between primary source part and secondary sensor part. This newly developed parameter estimation system can be easily applied to the Ambient Intelligent System including the ubiquitous computing and the sensitive environmental changes.