• Journal of Power Electronics
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• 제4권1호
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• pp.18-27
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• 2004

The output storage capacitor of the PFC converters is commonly designed for the selected hold-up time or the allowed output ripple voltage percentage. Nevertheless, this output capacitor is a main contribution factor to the PFC system stability. Moreover, seeking for a minimum output storage capacitor that assures the PFC desired operation under all condition, and providing the advantage of a small size and low cost is the main interesting target for engineering. Therefore, in this issue the design steps of the PFC converter have been discussed depending on three choices, output ripple, hold-up time, and stability. It is cleared that any design must take the minimum required storage capacitor for stability prospective as step-l in deign, then apply for any other specification like hold-up time or ripple percentage.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2005년도 춘계학술발표대회
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• pp.1705-1708
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• 2005

Recently, flash memory is becoming popular as storage system to store and retrieve multimedia files. However, there are few researches about multimedia file system for flash memory based storage devices. We have been designing and developing a novel multimedia file systems for flash memory. In this paper, we describe the semantics of real-time retrieval of multimedia data and present scheduling scheme to guarantee the real-time requirements in our multimedia file system.

• 한국컴퓨터정보학회논문지
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• 제5권4호
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• pp.106-111
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• 2000

멀티미디어 화일 전송과 같은 실시간 응용에서 저장시스템으로서 디스크 배열의 사용은 필수적이다. 멀티미디어 데이터 저장 서버에서 동시에 보다 많은 고객들에게 요청되어지는 서비스를 제공하기 위해서는 여러 분야에서의 다양한 정책들이 고려될 수 있으나, 특히 시스템의 환경과 비디오 데이터의 특성에 따른 스트라이핑 블록 크기의 관계와 같은 여러 가지 디스크 배열 특성변수들은 성능을 좌우하는 중요한 요인이다. 본 논문에서는 실제 멀티미디어 서버의 환경에 저장시스템과 관련된 특성변수들을 다양한 작업부하에 적용해 봄으로써 최적의 저장시스템 구조를 평가하였다.

• 정보저장시스템학회논문집
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• 제1권2호
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• pp.137-142
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• 2005

In this paper, we propose a new servo system design strategy to reduce the position error signal(PES) and track mis-registration(TMR) in magnetic disk drive systems. The proposed method provides a systematic design procedure based on the plant model and an optimal solution via an optimization with a 'Robust Random Neighborhood Search(RRNS)' algorithm. In addition, it guarantees the minimum PES level as well as stability to parametric uncertainties. Furthermore, the proposed method can be used to estimate the performance at the design stage and thus can reduce the cost and time for the design of the next generation product. The reduction of PES as well as robust stability is demonstrated by simulation and experiments.

• 대한산업공학회지
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• 제24권4호
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• pp.579-589
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• 1998

Full turnover-based storage policy (FULL) is often used to minimize the travel time needed to perform storage/retrieval operations in automated storage/retrieval systems (AS/RSs). This paper presents an approach for determining the required storage capacity for a unit load AS/RS under the FULL. An analytic model is formulated such that the total cost related to storage space and space shortage is minimized while satisfying a desired service level. To solve the model, some analytic properties are derived and based on them, an iterative search algorithm which always generates optimal solutions is developed. To illustrate the validity of the approach, an application is provided when the standard economic-order-quantity inventory model is used.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.469-475
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• 1991

In this paper, we suggest the exact perturbation analysis(Exact_PA) technique with respect to the buffer storage in tandem queueing networks, through which the optimal buffer storage design problem is considered. The discrete event dynamic equations for the departure time of a customer are presented together with the basic properties of Full Out(FO) and No Input(NI) with respect to the buffer storage. The new perturbation rules with respect to the buffer storage are suggested, from which the exact perturbed path can be obtained. The optimal buffer storage problem is presented by introducing a performance measure consisting of the throughput and the buffer storage cost. An optimization algorithm maximizing this performance measure is derived by using the Exact_PA technique. The proposed perturbation analysis technique and the optimization algorithm are validated by numerical examples.

• 한국식품조리과학회지
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• 제24권5호
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• pp.565-572
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• 2008

The principal objective of this study was to determine the optimal conditions for making muffins with sea-tangle powder, which is known to be a healthy food supplement. The characteristics of the sea-tangle muffins were analyzed in a quality evaluation. Sea-tangle powder was added to the muffins at concentrations of 0%, 5%, 10%, 15%, 20% prior to baking. The height of the muffins to which the sea-tangle powder had been added, after storage at $20^{\circ}C$, was shown to decrease with increases in the concentration of sea-tangle powder. The weight of the muffins increased with increasing storage time, but these differences were not profound. The moisture content of the muffins decreased with increased storage time. The change in pH in accordance with storage time differed only slightly. In terms of the color of the sea-tangle powder-supplemented muffins, after storage at $20^{\circ}C$, the “L” and “b” values decreased with increasing amounts of added sea-tangle powder. The “a” value increased with increasing amounts of added sea-tangle powder. With regard to the textural properties of the sea-tangle powder-supplemented muffins, after storage at $20^{\circ}C$, the hardness and chewiness increased with greater quantities of added sea-tangle powder. Springness, cohesiveness, and adhesiveness differed only slightly as more sea-tangle powder was added. With regard to the sensory characteristics of the muffins, the overall quality of the muffin to which 10% sea-tangle powder was added was evaluated as the best. The color, flavor, and softness were also assessed as the highest. The sweetness of the muffins was assessed as weak.

• Asian-Australasian Journal of Animal Sciences
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• 제19권2호
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• pp.292-296
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• 2006

Meat marination has been applied to improve product's physical and sensory attributes for years, but usually it is not intended to improve microbial quality of the product. Tumbling, which helps the distribution of marinade solution during processing, should enhance the action of antimicrobial agents. The objective of this study is to evaluate the combined effects of nisin, tumbling and storage time on total microflora and psychrotrophs counts on poultry. A marinade that contained acetic acid (1%) and salt (3%) with pH adjusted to 4 was developed as a standardized marinade. Drumsticks were marinated with various nisin levels (0, 50, or 100 IU/ml) combined with tumbling (0, 10, or 20 min), and then stored at $4^{\circ}C$ for 18 h. The total microflora and psychrotrophs counts of the samples were evaluated after 0, 2, 4, and 7 days of storage. The results indicated that at a given storage time, the samples tumbled for either 10 or 20 min had significantly (p<0.05) lower microbial counts when compared with the samples without the tumbling treatment. The microbial counts of the tumbled samples increased as storage time increased. Microbial counts significantly (p<0.05) decreased when more nisin was increased up to the level of 100 IU/ml. In conclusion, adding of nisin at the level of 50 IU/ml with tumbling for 10 min decreased the total microflora and psychrotrophs counts of the marinated chicken broiler drumsticks.

• 한국식품조리과학회지
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• 제8권3호
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• pp.309-314
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• 1992

The purpose of this study was to investigate me effects of garlic or lemon juice on quality characteristics of fish muscle. The samples treated with garlic or lemon juice by me amount of 5% or 10% (w/w) of fish muscIe were stored at $4{\pm}1^{\circ}C$ and $-18{\pm}2^{\circ}C$ for 10 and 40 days, respectively. The results are summarized as follows; 1. In me taste of samples, me samples treated with 5% garlic juice showed me most favorite tendency all me storage time at $4{\pm}1^{\circ}C$ and $-18{\pm}2^{\circ}C$. 2. There were significant in fishy odor after 5 days of storage at $4{\pm}1^{\circ}C$ and 40 days of storage at $-18{\pm}2^{\circ}C$ . The fishy odor of samples treated with garlic juice were weaker man those of samples untreated or treated with lemon juice. 3. The appearance was evaluated the worst in 10% lemon juice treated sample among all me samples. 4. The hardness of the samples treated with lemon juice were lower man those of samples untreated or treated with garlic juice during all the storage time at $4{\pm}1^{\circ}C$ and $-18{\pm}2^{\circ}C$. 5. The score of overall quality was the highest in sample treated with 5% garlic juice during all the storage time at $-18{\pm}2^{\circ}C$.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.1261-1266
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• 2008

Experimental study was performed to understand the operations of a showcase working in a discount store. Temperatures of evaporation, condenser were measured and also electric power consumption of compressor were measured. The purpose of this study is to application use of cold-heat storage systems operated the showcase. At the condition using ice storage system, the ice making process was operated during midnight being not needed the cooling of the showcase through the continuous running of the condenser unit. And then, the refrigerant was sub-cooled using stored cold-heat after being discharged from the air cooling condenser during the day time. The cooling performance was increased owing to the sub-cooling of refrigerant during day time, hence the running time of the compressor was effectively decreased. In other words, this study showed that power consumption during daytime can be transferred to the midnight for making use of the refrigerant sub-cooling. So the operating characteristics of the showcase system under various working conditions were analyzed and discussed.