• 한국콘텐츠학회논문지
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• 제5권3호
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• pp.183-191
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• 2005

송신자 개시 부하 균형 알고리즘에서는 전체 시스템이 과부하일 때 송신자(과부하 프로세서)가 부하를 이전하기 위해 수신자(저부하 프로세서)를 발견할 때까지 불필요한 이전 요청 메시지를 계속 보내게 된다. 따라서 이 같은 상황에서는 저부하 상태인 수신자 프로세서로부터 승인 메시지를 받기까지 불필요한 프로세서 간 통신으로 인하여 프로세서의 이용률이 저하되고 또한 태스크의 처리율이 낮아지는 문제점이 발생한다. 본 논문에서는 이질형 분산 시스템에서의 동적 부하 균형을 위해 유전 알고리즘을 기반으로 하는 접근 방법을 제안한다. 이 기법에서는 불필요한 요청 메시지를 줄이기 위해 요청 메시지가 전송될 프로세서들이 제안된 유전 알고리즘에 의해 결정된다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제10권3호
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• pp.24-31
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• 2005

2차원 불균질 대수층에서 다수의 오염원이 있음 경우 오염물의 거동을 모사할 수 있는 방법을 제시하였다. 이 방법은 유선 시뮬레이션을 기반으로 하며 다차원의 계산을 다수의 일차원으로 분해하여 계산하는 방법으로서 불균질한 매질에서 수두 계산을 한 후, 관심영역에 유선을 분포시키고 그 유선을 띠라 오염물이 전파되는 농도를 계산한다. 개발된 모델을 Visual MODFLOW를 이용하여 검증하였고 시간에 따른 농도 분포나 관측정에서의 용질 도달 곡선이 잘 일치함을 확인할 수 있었다. 개발된 모델은 시뮬레이션 수행 시간에 대한 효율 면에서 Visual MODFLOW보다 뛰어나 많은 연산을 필요로 하는 대규모 대수층의 용질거동 예측이나 반복 계산을 필요로 하는 역산 모델링에서 효과적으로 사용될 수 있다.

• 한국CDE학회논문집
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• 제13권2호
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• pp.89-97
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• 2008

Today's manufacturing environment is becoming a distributed manufacturing process in which a unique and specialized technological background is required in specific domains rather than having a single company execute all the manufacturing processes. This phenomenon is especially true in the automotive industry, where the sharing of product data between companies is rampant; however, this kind of interoperability causes many problems. When each company has its own method of managing product data, the sharing of product data in a distributed environment is a major problem. A data translator module or a data mapping module had to be developed for the exchange of data in heterogeneous systems of product data management (PDM); moreover, this type of module must be continually changed and improved due to the fact that PDM systems change for many reasons. In addition, the growth in corporate partnerships deepens the burden of developing and maintaining this module and creates further data exchange problems due to the increasing complexity of the system. This paper introduces a way of exchanging product data among heterogeneous PDM systems through the use of OpenPDM, which is a kind of virtual data warehouse. The implementation of a PDM integrating system is also discussed with respect to the requirement for a logical integration of product data which are physically distributed.

• 한국대기환경학회지
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• 제12권4호
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• pp.487-494
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• 1996

Simultaneous effects of $C_2H_4$ injection and heterogeneous chemical reactions on non-thermal plasma process to remove $SO_2$ and NOx from flue gas were investigated in the present experimental study. The present results showed that 40% of the electrical power can be reduced in $C_2H_4$ injection and heterogeneous chemical reaction are simultaneously included in the non-thermal plasma precess. As an effort to apply the non-thermal plasma technique to practical flue gas treatment system, a wire-plate type reactor which has technically similar geometry of industrial electrostatic precipitators is used instead of other types of reactors, such as wire-cylinder, packed-bed and surface discharge which are inappropriate to industrial application. In the present study, the photo pictures of positive streamer corona taken by ICCD camera, voltage and current oscillograms, and design criteria of a wire-plate type reactor are also shown, which are needed for industrial application of the non-thermal plasma process.

• Environmental Engineering Research
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• 제18권4호
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• pp.267-276
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• 2013

This study presents a comparison of different protocols for the synthesis of iron-loaded zeolites, and the results of their application, as well as that of zeolite-A (Z-A), to the removal of ammonium and phosphate from aqueous media. Zeolites prepared by three methods were evaluated: iron-incorporated zeolites (IIZ), iron-exchanged zeolites (IEZ), and iron-calcined zeolites (ICZ). The optimal iron content for preparing of IIZ, as determined via scanning electron microscopy and X-ray photoelectron spectroscopy analyses, expressed as molar ratio of $SiO_2:Al_2O_3:Fe$, was below 0.05. Ammonia removal revealed that the iron-loaded zeolites have a higher removal capacity than that of Z-A due, not only to ion-exchange phenomena, but also via adsorption. Greater phosphate removal was achieved with IEZ than with ICZ; additionally, no sludge production was observed in this heterogeneous reaction, even though the coagulation process is generally accompanied by the production of a large amount of undesired chemical sludge. This study demonstrates that the developed synthetic iron-loaded zeolites can be applied as a heterogeneous nutrient-removal materials with no sludge production.

• Journal of Communications and Networks
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• 제18권1호
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• pp.112-122
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• 2016

Cognitive radio (CR) is considered an attractive technology to deal with the spectrum scarcity problem. Multi-radio access technology (multi-RAT) can improve network capacity because data are transmitted by multiple RANs (radio access networks) concurrently. Thus, multi-RAT embedded in a cognitive radio network (CRN) is a promising paradigm for developing spectrum efficiency and network capacity in future wireless networks. In this study, we consider a new CRN model in which the primary user networks consist of heterogeneous primary users (PUs). Specifically, we focus on the energy-efficient resource allocation (EERA) problem for CR users with a special location coverage overlapping region in which heterogeneous PUs operate simultaneously via multi-RAT. We propose a two-tier crossover genetic algorithm-based search scheme to obtain an optimal solution in terms of the power and bandwidth. In addition, we introduce a radio environment map to manage the resource allocation and network synchronization. The simulation results show the proposed algorithm is stable and has faster convergence. Our proposal can significantly increase the energy efficiency.

• 한국물환경학회지
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• 제35권2호
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• pp.115-122
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• 2019

The objective of this study was to investigate the sonophysical and sonochemical effects induced by acoustic cavitation in heterogeneous systemin a 28 kHz double-bath reactor using calorimetry, the aluminiumfoil erosion test, and the luminol test. With no glass beads, calorimetric power in the inner vessel increased as much as the outer sonoreactor lost and total calorimetric power was maintained for various liquid height conditions (0.5 ~ 7 cm) in the vessel. Higher calorimetric energy was obtained at higher liquid height conditions. Similar results were obtained when glass beads were placed with various beads heights (0.5 ~ 2.0 cm) and relatively high calorimetric energy was obtained in spite of large attenuation in the glass beads layer. An aluminium foil placed between the bottom of the inner vessel and the glass beads layer was damaged, indicating significant sonophysical effects. Much less damage was detected when the foil was placed above the beads layer due to large attenuation of ultrasound. Sonochemical effects, visualized by sonochemiluminescence (SCL), also decreased significantly when the beads were placed in the vessel. It was established that the optimization of the liquid height above the solid-material layer could enhance the sonophysical and sonochemical effects in the double-bath sonoreactors.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1997년도 Proceedings International Workshop on New Video Media Technology
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• pp.49-54
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• 1997

For the purpose of a flexible coded video transmission over a heterogeneous network, we propose a new packetization method for coded video data. The proposed method achieves small degradation of coded picture quality in case of packet discard at the network node and does not require heavy processing load for bitrate control operation. Computer simulation results show that the bitrate reduction from 384 kb/s to 192 kb/s does not cause severe degradation in picture quality.

• 산경연구논집
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• 제10권5호
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• pp.49-58
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• 2019

Purpose - Consumer behaviors or decision-making process has been changing recently as the consumer environment, including mobile everyday life, has changed. In view of this changing consumer smart environment, this study aims to investigate structural relation about the influence omni-channel propensity and regulatory focus on consideration set formation. Research design, data, and methodology - In order to proceed with this study, we review previous studies and setting hypotheses. The hypothesis was verified through a survey that was conducted for university students with experience in purchasing in less than three months. With reference to previous studies, operational definition was made for the questionnaire design. From 2018 Nov. to 2019 Feb. Survey was conducted on the panel consumers who purchase item within that period. 315 collected survey data were used to verify hypotheses except the data that had incorrect values. This data were used for SPSS/AMOS for confirm hypothesis which developed by researcher. Results - The results of this study are as follows. First, Consumers were considering a more heterogeneous alternatives if they were more omni-channel propensity in the process of forming consideration set. Second, Consumers were more conscious of the price if they were more omni-channel propensity Third, Consumers were considering a more newness alternatives if they were more omni-channel propensity in the process of forming consideration set. Meanwhile, The results of the study on regulatory focus and consideration set relationships are as follows. Consumers were considering a more heterogeneous alternatives if they were more promotion focus tendency in the process of forming consideration set. Second, Prevention focus tendency were more conscious of the price in the process of considering alternatives. Third, Consumers were considering a more newness alternatives if they were more promotion focus tendency. Conclusions - Depending on the changing consumer environment, the omni-channel propensity was shown to influence the formation of the consideration set. Also, Regulatory focus of consumers significantly influence to formation of consideration set. this study also contributes to the development of the theory as well as the practical approach with understanding consumer decision process on smart(mobile) environment.

• 한국정보과학회논문지:시스템및이론
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• 제32권5호
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• pp.209-218
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• 2005

본 논문에서는 현실세계의 사용자와 주변 환경의 컨텍스트를 이용하여 가상환경과 상호작용하는 컨텍스트 기반 분산 갸상 환경 시스템을 제안한다. 제안된 시스템은 컨텍스트를 이용변경, 공유함으로써 다음과 같은 특징을 갖는다. 첫째, 가상환경의 응용서비스는 사용자의 신원, 연령, 언어 등의 컨텍스트에 따라 가상 환경을 제어하기 위한 인터페이스를 변경함으로써 개인화된 상호작용 환경을 보장한다. 둘째, 가상 환경에 있는 대상물을 제어하는 사용자의 입력 장치 신호를 컨텍스트 정보로 추상화함으로써 사용자가 다른 가상 환경 시스템으로 이동하여도 동일한 입력 장치를 가지고 해당 대상물을 제어할 수 있는 가상 환경과 장치의 적응적 접근성(adaptive access)을 보장한다. 마지막으로 분산 가상 환경 시스템들은 가상환경 변화에 대한 컨텍스트를 공유하여 이기종의 가상 환경 시스템 사이에서 발생하는 데이타 표현의 불일치성을 제거함으로써 이기종 분산 가상 환경 사이의 효과적인 동기화 메카니즘(synchronization)을 제공한다. 따라서 CIVE는 원격회의, 게임, 가상문화 관람 등과 같이 짐차 보편화되고 있는 가상환경 응용분야에서 활용될 수 있다.