• 전기학회논문지
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• 제67권1호
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• pp.22-28
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• 2018

In case of developing a combined system by a number of distributed resources with storage device, a number of application suggests a huge capacity can derive operational flexibility both power supply issues or when unexpected situation imposed. However, it is important to determine a resonable energy capacity because the device have many controversial cost issues in current power system industry. An ESS application which focusing essentially required points can induce appropriate storage capacity that required in economic operation. In this paper, a curtailment supporting algorithm based on storage device is introduced, and applied in the capacity calculation method. The main algorithm pursues handling minor exceeding quantities which can cause mechanical load at blade; This paper tries to include it for configuring hybrid algorithm with pitch control. Several fluctuating conditions are utilized in simulation to reflect critical situation. The analyzing process focuses on the control feasibility with applied capacity and control method.

• 정보저장시스템학회논문집
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• 제6권1호
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• pp.31-36
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• 2010

Data storage related with writing and retrieving requires high storage capacity, fast transfer rate and less access time. Today any data storage system cannot satisfy these conditions, however holographic data storage system can perform faster data transfer rate because it is a page oriented memory system using volume hologram in writing and retrieving data. System can be constructed without mechanical actuating part so fast data transfer rate and high storage capacity about 1Tb/cm3 can be realized. In this research, to correct errors of binary data stored in holographic data storage system, a new method for reduction errors is suggested. First, find cluster centers using subtractive clustering algorithm then reduce intensities of pixels around cluster centers. By using this error reduction method following results are obtained ; the effect of Inter Pixel Interference noise in the holographic data storage system is decreased and the intensity profile of data page becomes uniform therefore the better data storage system can be constructed.

• 한국산림과학회지
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• 제83권3호
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• pp.391-399
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• 1994

임지(林地)의 지피상태별(地被狀態別) 침투능(侵透能)을 조사, 분석하여 임지의 수저유(水貯留) 특성(特性)을 밝히고, 임지의 수보전기능(水保全機能)을 계량화(計量化)하기 위해 경북(慶北) 경주군(慶州郡) 내남면(內南面) 용장리(茸長里) 소재(所在) 영남대학교(嶺南大學校) 농축산대학(農畜産大學) 부속(附屬) 연습림(演習林)에서 1993년(年) 6월(月)부터 9월(月)에 걸쳐 수행한 연구결과는 다음과 같다. 1. 지피상태에 따른 임지 표층 (0~20cm)의 침투능은 참나무림지 > $A_o$층을 제거 한 참나무림지 > $A_o$층을 제거한 소나무림지>소나무림지>임간라지(林間裸地)>초지(草地)의 크기 순위였다. 2. 강우강도(降雨强度)의 증대에 따른 지피상대별 침투능의 순향(順向)은 큰 변화가 없었고, 침투능의 절대량(絶對量)은 증가하였다. 3. 침투능과 그 영향인자들과의 상관관계(相關關係)에 있어 서 침투능은 토양경도(土壤硬度) 및 전공극량(全孔隙量)과 고도(高度)의 상관이 있었다. 4. Horton의 침투식(侵透式) 모형(模型)에 근거한 침투방정식(侵透方程式)을 지피상태별로 각각 추정(推定)할 수 있었다. 5. 전공극과 토양경도를 이용하여 나타낸 침투능으로 임지의 수저류량 추정모델을 산출(算出)할 수 있었다. 본 연구에서는 침투능이 산지지피상태에 따라 차이를 보이고 있음을 밝혔고, 침투능에 영향을 미치는 주요인자를 구명함과 동시에 추정식을 산출하였다. 이 결과로 산지의 수원함양기능의 계량화에 접근할 수 있었으며 또한 산지의 효율적인 수자원 관리를 위한 대책수립에 도움을 줄 것으로 기대된다.

• Journal of Biosystems Engineering
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• 제27권1호
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• pp.39-44
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• 2002

In order to obtain the information of bio-environment control, the thermal characteristics of soil in the greenhouse heated by the heat pump and latent heat storage system were experimentally analyzed. The experimental systems were composed of the greenhouse with a heat pump and a latent heat storage system (system I), the greenhouse with a heat pump (system II), the greenhouse with a latent heat storage system (system III), and the greenhouse without auxiliary heating system (system IV). The thermal characteristics experimentally analyzed in each system were temperature of soil layers, soil heat storage and release, soil heat capacity and soil heat storage ratio. The results could be summarized as follows. 1. Time to reach the highest temperature at 20cm deep in soil layers of the crop routs in case of system I was shown to be delayed by 6 hours in comparison to the time of the highest temperature at the soil surface. 2. In the clear winter days, the stored heat capacity values fur the system I and the system II were shown to be 22.3% and 11.0% higher than the released heat capacity respectively, and the stored heat capacity values for the system III and the system IV were shown to be 6.2% and 29.6% lower than the released heat capacity respectively This confirms that the system I provided the best heat storage effect. j. The heat quantity values stored or released were shown to be highest at 5 cm depth of soil layers. And it was reduced with increasing of depth of soil layers until 20 cm and was not changed under the soil layer of 20 cm depth. 4. The heat absorption rates of soil, the ratio between supplied and stored heat energy, fur both the system I and system II were lower than 23%.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2012년도 춘계학술발표대회 논문집
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• pp.529-533
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• 2012

By introducing RPS(Renewable Portfolio Standard) for reduction of greenhouse gas, Renewable energy sources have becoming widespread gradually. However, Renewable energy sources, such as wind power and PV are difficult to control the output and they have intermittent characteristics of the output. These characteristics would cause some problems when it is connected in the power system. In order to solve these problems, Energy Storage Systems(ESS) are considered to use. Although there are many different storage devices, the utilization of Secondary Battery is the one of the best ways to stabilize an output fluctuation of RES because of its fast responsibility. For that reason, it would better fit a large-capacity of Secondary battery for stabilization. However, batteries cannot be installed with a large capacity blindly because of its expensive cost. So to select proper capacity of the battery is an important consideration. This paper presented a methodology for the optimal capacity and operation of ESS in microgrids.

• 정보저장시스템학회:학술대회논문집
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• 정보저장시스템학회 2005년도 추계학술대회 논문집
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• pp.83-87
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• 2005

Data storage related with writing and retrieving requires high storage capacity, fast transfer rate and less access time in. Today any data storage system can not satisfy these conditions, but holographic data storage system can perform faster data transfer rate because it is a page oriented memory system using volume hologram in writing and retrieving data. System architecture without mechanical actuating pare is possible, so fast data transfer rate and high storage capacity about 1Tb/cm3 can be realized. In this paper, to correct errors of binary data stored in holographic digital data storage system, find cluster centers using clustering algorithm and reduce intensities of pixels around centers. We archive the procedure by two algorithms of C-mean and subtractive clustering, and compare the results of the two algorithms. By using proper clustering algorithm, the intensity profile of data page will be uniform and the better data storage system can be realized.

• 대한산업공학회지
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• 제18권1호
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• pp.11-24
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• 1992

The performance of Storage assignment policies is traditionally evaluated with the storage capacity of and AS/RS taken as given. However, the storage capacity is closely related to the inventory model used in real situations. This paper presents a model of evaluating the performance of three storage policies(random storage, class-based storage, and full turnover-based storage) considering production lot-sizing simultaneously with storage assignment of inventory items. The objective of the model is to achieve a balance of warehouse throughput and space requirements such that a total of material handling cost, production ordering cost, and inventory holding cost is minimized. The effects of the parameters involved in the model are investigated on the performance of each storage policy through example problems.

• 전기학회논문지
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• 제63권8호
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• pp.1159-1163
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• 2014

This paper have been dealt with the analysis for energy efficiency improvement effect of unity storage capacity as a part of the energy storage application study to improve energy efficiency in the electric railway systems. Especially, in order to estimate the amount of energy saving according to the variation of power capacity of each storage, the current limit module was mounted on an existing DC electric railway loadflow program which is based on the analysis model for railway system and storages, and combined optimization algorithm to determine optimal voltage boundary.

• 한국농공학회지
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• 제40권2호
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• pp.69-80
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• 1998

The optimal reservoir storage capacity is needed to be determined at the stage of reservoir planning. The reservoir storage capacity should be based on water balance between demand and supply, and meet the water deficity during the growing season. However, the optimal reservoir storage capacity should be determined considering benefit-cost analysis for the project. In this study, Two models are developed. The one is the RSOM(Reservoir Storage Optimization Model), that is consisted by three submodels, MROPER (Modified Reservoir OPERation model), RESICO(REservoir SIze and the construction COst computation) model. And the other is the BECA(BEnefit-Cost Anaysis) model. For model application, three districts, Chungha, Ipsil and Edong were selected. The relative difference of B/C ratio between project planning data and estimation by RSOM is 17.9, 15.0 and 7.3% respectively, which may be applicable for water resources development feasibility planning.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.697-700
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• 2007

Six thousands of vehicles are operated on Korean urban transit system. 95% of them have regeneration system. Especially, the VVVF-Inverter vehicle has a merit of the highest regeneration rate. Therefore, the energy storage system is needed to be developed to use regeneration energy when the vehicle is braking. Therefore, Measuring regeneration energy in the substation need to know how much regeneration energy occurs, how much capacity of energy storage system is needed. After measuring regeneration energy, we design the capacity of energy storage system.