• 설비공학논문집
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• 제23권6호
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• pp.406-412
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• 2011

This paper describes the analysis on freeze and refrigeration capacity of cold storage facilities for fisheries products during the last 15 years. And based on the analysis results, we prospect the number and scale of cold storage facilities in the near future. The main analysis results are summarized by the followings; Under the present conditions, the number and scale of our facilities is 879 and 3,586,824 ton, respectively. In comparison of the present and last 15 years ago, the business number increases about 22%, the accommodation capacity increases approximately 80%. In the reported update reference with the related data during the last 15 years, the capacity of cold storage facilities in 2011 expects to reach up to 4,600,000 ton. The newlyestablished facility in 2011 has the function of a multi-purpose distribution center as well as the existing cold storage, but this facilities converges in the capital area. Therefore, in this paper, we provided the basic reference data for the present situation and prediction of our cold storage facilities. But it is necessary to investigate and analyse widely our cold storage facilities for fisheries products in the near future.

• Nuclear Engineering and Technology
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• 제55권10호
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• pp.3898-3906
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• 2023

The paper notes that the most common way of handling spent nuclear fuel (SNF) of power reactors is its temporary long-term dry storage. At the same time, the operation of the dry spent fuel storage facilities almost never use the modern capabilities of information systems in safety control and collecting information for the next studies under implementation of aging management programs. The author proposes a structure of an information system that can be implemented in a dry spent fuel storage facility with ventilated storage containers. To control the thermal component of spent fuel storage safety, a database structure has been developed, which contains 5 tables. An algorithm for monitoring the thermal state of spent fuel was created for the proposed information system, which is based on the comparison of measured and forecast values of the safety criterion, in which the level of heating the ventilation air temperature was chosen. Predictive values of the safety criterion are obtained on the basis of previously published studies. The proposed algorithm is an implementation of the information function of the system. The proposed information system can be used for effective thermal monitoring and collecting information for the next studies under the implementation of aging management programs for spent fuel storage equipment, permanent control of spent fuel storage safety, staff training, etc.

• 한국재료학회지
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• 제2권3호
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• pp.220-227
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• 1992

전기유변유체(electrorheological fluid : ERF)는 크기가 $10^{-6}m$정도를 가진 분극성이 강한 입자 분말을 유전유체속에 혼합하여 만든 콜로이드용액으로서 외부전기 장에 의하여 액체상태로부터 겔(gel)상태로 상태변환을 한다. 상태변환과정은 가역과정이며 $10^{-3}$초 정도의 빠른 시간내에 이루어진다. 본 논문에서는 주기적응력이나 주기적 변형이 가해지는 강제진동실험을 통하여 ERF의 점탄성 특성을 조사하였다. 점탄성은 복소수로서 실수부인 동적전단탄성율(storage shear modulus, G')과 허수부인 동적손실율(loss modulus, G")의 합으로 표현된다. 동적전단탄성율은 강제진동의 진폭과 주파수의 함수로 외부전기장에 의하여 크게 변화되었으나 손실계수(loss factor, ${\eta}=G"/G'$)는 진동의 진폭, 진동수 및 외부전기 장에 거의 독립적이었다. 실험(1)은 강제진동의 진폭을 고정하고 진동수를 변화하는 방법(frequency sweep)과 실험(2)는 진동 진폭을 변화시키는 방법(amplitude sweep)으로 실행했다. 본 실험에서는 cornstarch입자를 corn oil에 혼합한 것과 zeolite입자를 silicone oil에 흔합한 콜로이드 용액이 ERF로서 사용되었으며 인가된 전기장은 약$(1~3){\times}10^6V/m$의 직류전기장이 가하여졌다.기장이 가하여졌다.

• 한국식품과학회지
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• 제43권4호
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• pp.419-425
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• 2011

머스크멜론의 저장온도 차이에 따른 저장 중 미세한 향기성분의 변화를 질량분석기 기반 전자코를 이용하여 품질 변화 정도를 판단하였다. 저장기간이 증가함에 따라 향기성분이 변화하면서 휘발성분이 증가하였는데, 판별함수분석 결과 DF1값이 99.8%로 큰 영향을 받았으며 향기성분의 변화가 크게 나타날수록 DF1 값이 음의 방향으로 이동하였다. 이후 DF1 뿐만 아니라 DF2도 음의 값으로 변하면서 저장 초기와는 확연히 다른 향기성분의 변화가 일어난 것으로 판단된다. 0$^{\circ}C$ 저장에서는 28일, 4와 7$^{\circ}C$에서는 21일, 10$^{\circ}C$에서는 14일까지 저장 초기와 유사한 향기성분을 나타났으며, 이는 저장 온도가 낮아질수록 휘발성분의 변화가 적게 일어났다. 이러한 향기성분의 변화는 머스크멜론이 저장 중숙기가 지나고 노화가 진행되어지면서 일어난 것으로 유추된다. 또한 전자코로 분석한 DF1 값을 이용하여 일반성분들(비타민 C 함량, 꼭지 수분함량, 산도)의 저장 중 경향도 예측 가능 하였다. 머스크멜론의 저장 중 변화하는 전자코의 mass spectrum에 나타난 주요 향기성분은 이미 보고된 GC/MS의 분석 결과와 유사한 ethyl acetate, butyl acetate, nonanol, dodecanoic acid, hexadecanoic acid, tricosane과 같은 성분들로 나타났으며, 저장 중 전자코에 감지되는 양은 계속적으로 증가하였다.

• 한국농공학회논문집
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• 제47권3호
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• pp.15-25
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• 2005

Ninety tow percent of over 1,800 gate controlled dams in Korea are classified as small dams. The primary purpose of these small dams is to supply irrigation water. Therefore, while large dams can store as much as 80 percent of precipitation and thus are efficient to control flood, small dams are often lack of flood control function resulting in increased susceptibility drought and flood events. The purpose of this study is to develope a storage management model for irrigation dams occupying the largest portion of small dams. The proposed Storage Management Model (STMM) can be applied to the Seongju dam for efficient management. Besides, the operation standard is capable of analyzing additional available water, considering water demand and supply conditions of watershed realistically. And the model can improve the flood control capacity and water utilization efficiency by the flexible operation of storage space. Consequently, if the small dams are managed by the proposed Storage management model, it is possible to maximize water resources securance and minimize drought and flood damages.

• 설비공학논문집
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• 제12권11호
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• pp.982-993
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• 2000

This paper describes an optimal control scheduling of an encapsulated ice storage system with a chiller of nominal chiller 34RT(103,200kcal/hr) and an ice storage tank of 170RT-hrs(514,080 kcal). The optimization technique used in the study is dynamic programing. The objective function is summed cost during a day including charge and discharge periods. Control strategies being used commercially are chiller priority and storage priority control. In chiller priority control, the chiller is allowed to run at full capacity during the day, subject to limitations of the building load, and the ice is only melted when and if the load exceeds the chillers full capacity. In contrast to chiller priority control, the aim in storage priority control is to melt as much as ice as possible during the day time period. The system simulation calculates the operation costs for the three control strategies in the condition of the same cooling load and the same ice storage system. The simulation period is a day, assuming that initially the tank is stored fully and the cooling load is perfectly predicted for the scheduling. Also Final state of the tank is to be charged fully.

• Journal of Power Electronics
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• 제9권1호
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• pp.51-60
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• 2009

Hybrid Electric Vehicles (HEVs) utilize electric power as well as a mechanical engine for propulsion; therefore the performance of HEV s can be directly influenced by the characteristics of the Energy Storage System (ESS). The ESS for HEVs generally requires high power performance, long cycle life and reliability, as well as cost effectiveness. So the Hybrid Energy Storage System (HESS), which combines different kinds of storage devices, has been considered to fulfill both performance and cost requirements. To improve operating efficiency, cycle life, and cold cranking of the HESS, an advanced dynamic control regime with which pertinent storage devices in the HESS can be selectively operated based on their status was presented. Verification tests were performed to confirm the degree of improvement in energy efficiency. In this paper, an advanced HESS with improved an Battery Management System (BMS), which has optimal switching control function based on the estimated State of Charge (SOC), has been developed and verified.

• 한국정보과학회논문지:데이타베이스
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• 제29권1호
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• pp.15-26
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• 2002

대부분의 멀티미디어 저장 시스템은 사용자의 요청을 라운드-로빈(round-robin) 방식으로 수행한다. 즉, 사용자는 일정한 간격을 두고 정해진 시간 동안 저장 시스템의 서비스를 받게 된다. 더욱이, 여기에 사용되는 대부분의 알고리즘들은 시스템과 밀접하게 연관된 비용함수를 바탕으로 평가를 받게 된다. 이러한 알고리즘의 FCFS, SCAN, SCAN-EDF 등이 있다. 본 논문에서는 주어진 사용자 요청에 대해서 사용자 대기 시간이나 최대 디스크 대역폭과 같은 제약 조건들을 만족시키는 동시에 임의의 비용 함수에 대해 최적의 스케줄인 통합 읽기 요청(Unified Read Request)을 생성하는 요청 통합기(Request Unifier) 모듈을 설계한다. 그리고 이러한 사용자 요청 통합에 사용될 수 있는 세 개의 알고리즘을 제안하고 성능 평가를 통해 그들의 장단점을 비교해 본다.

• 한국인터넷방송통신학회논문지
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• 제19권6호
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• pp.191-196
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• 2019

도시철도 시설물의 경우, 대중교통의 특성상 전력공급이 차단되면 혼란이 발생하므로 통신설비, 방재설비 및 승차장 안전문 등이 안전한 승객의 이동을 위해 전원공급이 유지되어야 한다. 또한, 도시철도 운행노선에는 다수의 전동차가 운행 중이므로 운행 간격과 시설복구 시간을 고려하면 승차장 안전문은 최소 30분 이상, 통신설비 및 방재설비는 1시간 이상의 설비가동이 요구된다. 따라서 도시철도 구간의 역사나 차량화재발생 시 화재로 인한 추가확산을 막기 위해 주요전력이 차단되므로 유도등 및 배연설비의 안정적 동작 유지를 위해 비상 전원공급이 필수적이다. 최근에는 비상시 정전을 방지하는 UPS (uninterruptible power supply, 무정전 전원공급장치) 기능과 가격이 저렴한 야간 시간대에 전기를 저장하였다가 주간 피크시간대에 사용할 수 있도록 하여 전기요금을 절감해주는 ESS 기능을 합친 비상발전용 UPS 기능을 갖춘 복합형 전력저장시스템을 개발하는 추세이다.

• 전기학회논문지
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• 제65권3호
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• pp.371-381
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• 2016

This paper presents a study on reliability assessment and new contribution function development of power system including Wind Turbine Generator(WTG) combined with Battery Energy Storage System(BESS). This paper develops and proposes new reliability contribution function of BESS installed at wind farms. The methodology of reliability assessment, using Monte Carlo Simulation(MCS) method to simulate sample state duration, is proposed in detail. Forced Outage Rate(FOR) considered probabilistic approach for conventional generators is modelled in this paper. The penetration of large wind power can make risk to power system adequacy, quality and stability. Although the fluctuation of wind power, BESS installed at wind farms may smooth the wind power fluctuation. Using small size system as similar as Jeju island power system, a case study of reliability evaluation and new proposed contribution function of power system containing WTG combined with BESS is demonstrated in this paper, which would contributes to BESS reliability contribution and assessment tools of actual power system in future.