• Journal of Biosystems Engineering
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• 제40권3호
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• pp.261-270
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• 2015

Purpose: Cold storage is the most popular method used to preserve highly perishable foods such as beef and fish. However, at refrigeration temperatures, the shelf life of these foods is limited, and spoilage leads to massive food waste. Moreover, freezing significantly affects the food's properties. Ice crystallization and growth during freezing can cause irreversible textural damage to foods through volumetric expansion, moisture migration induced by osmotic pressure gradients, and concentration of solutes,which can lead to protein denaturation. Methods: Although freezing can preserve perishable foods for months, these disruptive changes decrease the consumer's perception of the food's quality. Therefore, the development and testing of new and improved cold storage technologies is a worthwhile pursuit. Results: The process of maintaining a food product in an unfrozen state below its equilibrium freezing temperature is known as supercooling. As supercooling has been shown to offer a considerable improvement over refrigeration for extending a perishable product's shelf life, implementation of supercooling in households and commercial refrigeration units would help diminish food waste. Conclusions: A commercially viable supercooling unit for all perishable food items is currently being developed and fabricated. Buildup of this technology will provide a meaningful improvement in the cold storage of perishable foods, and will have a significant impact on the refrigeration market as a whole.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제51권11호
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• pp.635-644
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• 2002

Many generating units can be in parallel connection to one battery and inverter. However, one of the biggest problems we encountered is that wind speed is fluctuated sharply in accordance with the unstable weather conditions. To solve this problem, we need energy storage equipment such as storage lead-acid battery. We design a system and analyze its modeling so that it supplies a stable power to the load through DC-AC inverter part. In this paper, we applied dual step-up/down buck-boost converter and dual high-frequency half-bridge converter to the proposed system. These converters are used to store energy in the battery regardless of the change of the wind speed. The operation process of two proposed types of converters for high-power battery charging is discussed along with simulation and experimental result. We design a charging circuit which is applicable in the actual wind power generation system for 30kw and confirm the circuit's validity.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2005년도 동계학술발표대회 논문집
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• pp.585-590
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• 2005

It can be said that refrigeration and air-conditioning technology in Korea dates back to the ancient Shilla dynasty, all the way up to the Sokkuram(700s) and Seokbinggo(1700s). But modem refrigeration and air-conditioning technology was first developed in and introduced to Korea in the 1960s with the modernization of Korea. Today it is at a level which meets that of advanced countries in both the industrial and domestic fields. 62 million units of refrigeration and air-conditioning machinery and equipment were produced in 2003, worth a total of 7.7 trillion won(about 7.7 thousand million US$). As of 2003, there were about 700 companies that owned cold storage / freezing / refrigeration facilities, with cold storage capacity of about 2 million ton and capacity per company of about 3 thousand ton. This facilities most are continuously expanding and automatizing their facilities.

• 전기학회논문지
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• 제65권8호
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• pp.1347-1354
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• 2016

This paper presents optimal operational scheduling model and economic assessment of Li-ion battery energy storage systems installed in non-residential customers. The operation schedule of a BESS is determined to minimize electric bill, which is composed of demand and energy charges. Dynamic programming is introduced to solve the nonlinear optimization problem. Based on the optimal operation schedule result, the economics of a BESS are evaluated in the investor and the social perspective respectively. Calculated benefits in the investor or customer perspective are the savings of demand charge, energy charge, and related taxes. The social benefits include fuel cost savings of generating units, construction deferral effects of the generation capacity and T&D infra, and incremental CO2 emission cost impacts, etc. Case studies are applied to an large industrial customer that shows similarly repeated load patterns according to days of the week.

• Asian-Australasian Journal of Animal Sciences
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• 제30권3호
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• pp.424-431
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• 2017

Objective: Study on the application of high pressure processing (HPP) for dark-firm-dry (DFD) beef was conducted to observe whether HPP has any impact on physical properties and to evaluate oxidative deterioration during refrigerated storage under vacuum. Methods: The longissimus lumborum muscles obtained from Friesian Holstein steers ($33{\pm}0.5$ months old) with 24-h postmortem pH higher than 6.0 were vacuum-packed and subjected to pressurization at 200, 400, and 600 MPa for 180 s at $15^{\circ}C{\pm}2^{\circ}C$; the samples were then stored for 9 days at $4^{\circ}C{\pm}1^{\circ}C$ and compared with control (0.1 MPa). Results: HPP increased meat pH by 0.1 to 0.2 units and the tenderness of cooked DFD beef significantly with no significant effects on meat texture profile. The stability of meat pH was well maintained during refrigerated storage under vacuum. No clear effects were found on the activity of catalase and superoxide dismutase, however, glutathione peroxidase activity was significantly reduced by high pressure. HPP and storage time resulted in aroma changes and the increasing amount of malondialdehyde and metmyoglobin relative composition. Conclusion: Although the increasing amount of malondialdehyde content, metmyoglobin formation and aroma changes in HPP-treated samples could not be avoided, HPP at 200 MPa increased $L^*$ and $a^*$ values with less discoloration and oxidative deterioration during storage.

• 한국컴퓨터정보학회논문지
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• 제25권10호
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• pp.1-14
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• 2020

이 논문에서는 낸드 플래시 메모리 기반 저장장치를 기존 섹터 기반 파일시스템에서 사용할 때 사상정보 관리개수의 증가로 인해 시스템 메모리 사용량이 증가하는 문제를 최대한 해결하기 위해 데이터 입출력 시 시간적집약성과 공간적집약성을 함께 고려한 사상기법을 제안한다. 제안기법은 색인 블록을 기반으로 페이지 단위로 사상정보만을 저장하여 이를 블록단위로 관리한다. 제안기법은 이를 위해 스몰 블록 내 하나에 페이지에 다수의 사상정보를 저장하여 관리하기 위한 순차 오프셋을 이용하며 블록 내에서 사상정보에 변경에 대응하는 여유페이지를 위한 역순 오프셋을 이용한다. 제안기법은 이를 통해 기존기법과 비교하여 블록단위 삭제 횟수가 적게 발생하며 사상정보 관리를 위해 필요한 시스템메모리 사용량이 낮은 장점이 있다 제안기법에 색인 블록 사상기법은 기존 로그블록 기법과 비교하여 블록병합 횟수를 약 32% 줄였다.

• 한국식품저장유통학회지
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• 제8권4호
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• pp.385-392
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• 2001

다양한 침지 저장액에 의한 깐밤의 갈변억제에 따른 저장 효과를 비교하였다. 총 폴리페놀의 함량은 저장초기에 13.36 mg%로 매우 낮게 나타났으나, 무처리구는 저장 17일까지 59.12 mg%로 증가 후 다시 감소하였다. 전해산화수 처리구는 저장 8일에 61.02 mg%로 갑작스런 증가를 보인 후 감소하였고, 그 외의 처리구에서는 저장 초기에 미세한 변화를 보이다가 저장 11일에 갑작 스럽게 증가하는 경량을 나타내었다. Polyphenol oxidase 활성의 변화는 기질의 증가시기보다 조금 앞서 증가되기 시작하였으며, 무처리구가 저장 11일에 1,152 units로 가장 높은 활성을 나타내었다. 그리고 명반수 처리구가 저장 8일에 1,117 units로 다른 처리구에 비하여 높은 활성을 나타내었다. 4주간 저장하였을 때에는 유자와 레몬과즙 첨가 전해산화수 처리구가 각각 143.3 units와 180.22 units을 나타내어 타 처리구에 비하여 갈변이 억제되는 것으로 나타났다. 색도 및 관능검사를 통하여 저장기간을 예측하며 본 결과, 무처리구의 경우는 14일, 명반수, 전해산화수 및 NaCl을 첨가한 전해산화수의 경우는 21일, 유자와 레몬을 첨가한 전해산화수 처리구는 28일까지도 저장이 가능한 것으로 나타났다.

• 대한간호학회지
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• 제14권1호
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• pp.34-49
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• 1984

This study was carried out to collect basic information of the budget and management of the nursing service equipment A survey was conducted with charge nurses (72), head nurses (400), supervisors (93), nursing directors (43) in 134 Hospitals The questionnaire was consisted of 34 questions related to management of budget, facility, supplies, and equipment We investigated from l0th to 22nd, Oct 1983. The results obtained were summarized as follows: 1) A budget for the department of nursing was 65.4% (51/78) 2) A budget commitee was 43.6% (34/78) 3) 51.3% took corrective action for the deviation from the budget, if indicated (40/78) 4) An established lost conciousness program in the hospital was 87.2% (64/68) 5) A formalized system for the maintenance of supplies for the patient care units was 87.2% 6) 87.9% had stocks level which was established for patient care units. 7) 64.6% had safeguards for the storage of special equipment which was investigated regularly in 54.7%. 8) The director of nursing or her representative, participates in the selection was 72.4%, 9) 58.2% was provided instruction in the use of equipment by manufacturers of technical equipment.

• 한국ITS학회 논문지
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• 제9권3호
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• pp.85-93
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• 2010

본 논문에서는 SOC 설계 자동화를 위한 할당 및 바인딩을 동시에 수행하는 새로운 동적인 하드웨어 할당 및 바인딩 알고리즘을 제안한다. 제안된 알고리즘은 스케줄링의 결과를 입력으로 받아들이고, 각 기능 연산자에 연결된 레지스터 및 연결 구조가 최대한 공유하도록 제어스텝마다 연산과 기억 소자의 상호 연결 관계를 고려하여 기능 연산자, 연결 구조 및 레지스터를 동시에 할당 및 바인딩을 한다. 제안된 알고리즘은 각 시스템마다 비교 실험을 통하여 기존의 기능 연산자와 레지스터의 수를 미리 정했거나, 분리하여 수행한 방식들과 비교함으로서 제안된 알고리즘의 효용성을 보인다.

• 한국주거학회논문집
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• 제12권2호
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• pp.1-12
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• 2001

The purpose of this study is to analyze characteristics of apartment housing unit plans based on analyzing overall patterns of housing unit plans and identifying the types of unit plans according to the size and to provide the fundamental data for developing diverse dwelling unit plans of apartment. This study deals with apartment housing unit plans built between 1999 and 2000 in Seoul, the capital region and new town. The major findings of this study are as follows; 1) Most apartment housing unit plans have fixed and uniform layouts. Most apartment housing units have L-DK type meaning they have isolated living room space. Certain layouts(especially $60-85\textrm{m}^2$ sized unit plans) show a "trickle-down" phenomenon with respect to the areas of units according to time series. 2) New plan types are rarely proposed since 2000, especially in large-sized(area more than $120\textrm{m}^2$) and $60-85\textrm{m}^2$ sized plans. 3) Another feature of apartment housing unit plans is increase of the service are (balcony, entrance area, additional kitchen, and storage area), and introduction of masters space (composition of master bedroom, dressing room, powder room, path, and etc.) and etc.)