• 전기학회논문지
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• 제63권8호
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• pp.1116-1120
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• 2014

With the shift of the energy paradigm from supply side management to demand side management, demand resource management and demand response plays an important role in the energy industry. As a consequency, a lot of researches have been done to provide a suitable demand response system. However, most of the demand response systems are based on the propriety products that cannot be modified. In this paper, we are proposing an automated demand response system using an EnerNOC provided open source code. We implemented the demand response server (VTN) and demand response client (VEN), and validated the OpenADR2.0 compliances using the open source code. We also used an Arduino microcontoller to demonstrate the communication schemes to control various devices.

• 한국통신학회논문지
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• 제32권10A호
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• pp.1004-1014
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• 2007

In sensor networks, it is crucial to reliably and energy-efficiently deliver sensed information from each source to a sink node. Specifically, in mobile sink (user) applications, due to the sink mobility, a stationary dissemination path may no longer be effective. The path will have to be continuously reconfigured according to the current location of the sink. Moreover, the dynamic optimal path from each source to the sink is required in order to reduce end-to-end delay and additional energy wastage. In this paper, an Adaptive Reversal Optimal path Tree (AROT) protocol is proposed. Information delivery from each source to a mobile sink can be easily achieved along the AROT without additional control overhead, because the AROT proactively performs adaptive sink mobility management. In addition, the dynamic path is optimal in terms of hop counts and the AROT can maintain a robust tree structure by quickly recovering the partitioned tree with minimum packet transmission. Finally, the simulation results demonstrate that the AROT is a considerably energy-efficient and robust protocol.

• 한국농공학회지
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• 제45권7호
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• pp.38-48
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• 2003

Lake water quality assessment information is useful to anyone involved in lake management, from lake owners to lake associations. It provides lake water quality criteria, which can improve the ways how to manage out lake resources and how to measure current conditions. It also provides a knowledge base so that the lakes can be protected and restored. Here, the Freshwater Lake Water Quality Management System(FLAQUM) was developed. The results of FLAQUM application by scenario proved that pollutant load at rainfall by the nonpoint sources was much more than normal times at rainfall. From the result of Scenario I (pollutant source increase case), the concentrations of Boryeong freshwater lake were BOD 9.43mg/L, T-N 4.53 mg/L and T-P 0.21 mg/L, respectively, and those values exceed the standard of agricultural water. And in case of Scenario I and II(the present case) excluding Scenario III (pollutant source decrease case), all of T-N and T-P are either mesotrophication or eutrophication, on the other hand when 60% of pollution source is removed, the concentrations of Scenario III were BOD 3.21 mg/L, T-N 0.95 mg/L, T-P 0.11 mg/L, respectively, and which satisfies the standard of agricultural water quality.

• 생물환경조절학회지
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• 제15권2호
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• pp.173-176
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• 2006

The relationship between source leaf position and photo-assimilate translocation and distribution was characterized for tomato (Lycopersicon esculentum Mill) grown in the greenhouse. Three different positions of source leaf on the stem (first node above or below the first fruit cluster and $5^{th}$ node above the first fruit cluster) were tested for their influence on $^{14}CO_2$ assimilation and transfer to different parts of the plant. The leaves at the $5^{th}$ node above the first fruit cluster transferred the highest (57%) proportion of $C^{14}$ to other plant parts, followed by leaves home on the first node below the first fruit cluster (50%), and the first node above the first fruit cluster (39%). In all treatments, fruits served as the strongest sink for $C^{14}$, followed by stem, leaf, and root tissues. The leaf home on the $5^{th}$ node above the first fruit cluster transferred the largest amount of $C^{14}$ to the second fruit cluster.

• KNOM Review
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• 제22권1호
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• pp.11-19
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• 2019

기술이 발전함에 따라 사용자에게 가해지는 네트워크상의 최신 보안 위협이 늘어나고 있다. 해커가 악의적인 목적을 가지고 산업 또는 기업의 시스템을 공격함으로써 기밀정보가 유출되거나 사이버 테러, 정보 자산의 침해, 금전적인 손해 등의 많은 사회 문제를 야기한다. 복잡하고 다양해지는 위협으로 인해 현 보안 인력만으로 모든 위협을 탐지하고 분석하기에는 역부족인 상황이 되었다. 특히, 365일 24시간으로 돌아가는 산업 기반 시설에서 사용하는 SCADA(Supervisory Control And Data Acquisition)는 정적인 데이터를 수집 및 분석하므로, 실시간으로 발생하는 보안 위협에 대해서는 매우 취약하다. 본 논문에서는 실시간으로 시스템의 상태를 모니터링이 가능하고 보안 위협을 탐지하는 강력한 통합 보안 관리 시스템인 SIEM(Security Information and Event Management)에 대해 소개한다. 다음으로 다양한 기업의 SIEM 솔루션들과 오픈 소스로 배포되는 AlienVault 사의 OSSIM(Open Source SIEM) 을 비교분석하고, OSSIM을 이용한 활용 사례와 OSSIM을 활용할 수 있는 방안을 제시한다.

• Journal of Power Electronics
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• 제2권4호
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• pp.288-296
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• 2002

In this paper, a high frequency transformer - assisted auxiliary active resonant commutated snubber (HFTA-ARCS) for voltage source soft switching pulse width modulated power conversion circuits is presented. A three phase voltage source type soft switching inverter incorporating HFTA-ARCS circuits in its three bridge legs can reduce current rating of auxiliary active power switches and has sensorless simplified control scheme which any specified boost current management is not required for soft switching. Its operation principle and digital control scheme are described and a practical design method of circuit parameters on this HFTA-ARCS circuit is also introduced on the basis of computer simulation. Moreover, this space voltage vector modulated soft switching inverter system with DSP-based digital control scheme Is discussed and its effectiveness is proved on the basis of performance evaluations. The operating performances of this inverter system are also compared with those of conventional three-phase hard switching inverter under practical conditions of specified parameters.

• Environmental Engineering Research
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• 제15권1호
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• pp.29-33
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• 2010

In 2004, the Korean government launched comprehensive measures for nonpoint pollution that were intended to reduce their amount by 34.3% over of those forecast by 2020. During the first and second stages of their implementation; from 2004 to 2011, nonpoint source (NPS) measures have focused on systemic improvements and project management, as well as the introduction of optimal management techniques; accordingly, reductions have been small. However, during the third stage in 2011, serious reductions will be pursued. Accordingly, the gradual expansion of sites subject to NPS measures has focused on the establishment of a basis for reduction measures in connection with model projects during the first half of the plan, with full scale enforcement due in the second half. For Korea, rather than commencing NPS management en masse, it has been more appropriate to gradate NPS management into stages tailored to the different needs of new and existing businesses, as well as to the needs of large and small-scale businesses, in consideration of their specific circumstances. This has allowed sufficient time for such businesses to become accustomed to the concept of NPS management.

• 한국관개배수논문집
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• 제18권2호
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• pp.54-65
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• 2011

This study was performed to analyze the influence of pollutant loads characteristics on the point and non-point sources in Saemangeum watershed area using Hydrological Simulation Program, Fortran (HSPF). The simulation items were flow, BOD, T-N, and T-P(2007~2010). The pollutant loads trend reflects the precipitation. Specifically, the point source loads were almost constant, but the non-point source loads were influenced in the precipitation. It was found that the effect of non-point source is larger than point source. The water quality had a clear trend by the season. However, pollutant loads did not show distinct seasonal changes. The reason is that the pollutant concentration is diluted by the increased flow at summer season. Therefore, it is important to control the non-point source in order to manage water quality in the region. For the management of Saemangeum lake, it is need to control of supplied pollutant loads from Saemangeum watershed.

• 한국물환경학회지
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• 제32권6호
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• pp.528-536
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• 2016

The purpose of Total Pollution Load Control at Tributary is to obtain maximum improvement effect of water quality through finding the most impaired section of water-body and establishing the proper control measure of pollutant load. This study was implemented to determine the optimal management of reach, period, condition, watershed, and pollution source and propose appropriate reduction practices using the Load duration curve (LDC) and field monitoring data. With the data of measurement, LDC analysis shows that the most impaired condition is reach V (G4~G5), E group (flow exceedance percentile 90~100%) and winter season. For this reason, winter season and low flow condition should be preferentially considered to restore water quality. The result of pollution analysis for the priority reach and period shows that agricultural nonpoint source loads from onion and garlic culture are most polluting. Therefore, it is concluded that agricultural reuse of surface effluent (storm-water runoff with non-point sources) and low impact farming that includes reducing fertilization and controlling the height of drainage outlet are efficient water quality management for this study watershed.

• Journal of Advanced Marine Engineering and Technology
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• 제35권3호
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• pp.335-340
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• 2011

Building energy saving is one of the most important issues in these days. Control algorithm for energy saving should be designed properly to reduce power consumption in building. Recently, building energy system consists of hybrid energy system coupling with RE (Renewable Energy) source. In this paper, an optimum control algorithm for building energy saving is applied to BEMS (Building Energy Management System) by using an outdoor air temperature prediction strategy. BEMS coupling with renewable energy can control HVAC (Heating, Ventilating and Air-Conditioning) system effectively. In order to verify the effectiveness of building energy saving, BEMS was tested for several months at a laboratorial chamber with an air conditioner, fan and heater. To this end BEMS embedded control algorithm has been tested successfully.