• 한국수산과학회지
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• 제55권6호
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• pp.946-953
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• 2022

Using the management strategy evaluation methods and data on the Korea chub mackerel Scomber japonicus where the state-space logistic production model is used as the operation and the estimation model respectivley, we examined the effects of both Dorn's rule, α and the buffer value for ABC (allowable biological catch), which are used by the Korea fishery managers for decision rules. We set scenarios that have different pairs of buffer and α values, which include those currently used in the management in Korea. Under each sceanario, we projected the fish population biomass until year 2050, during which ABC is determined in each year with the decision rule. We used three kinds of performance measures: (i) whether the biomass in 2050 is overfished; (ii) the average of annual yields over the simulation period; and (iii) the variability of annual yields over the period. We found that the current practice (buffer=0.9, and α = 0.05) resulted in the best performance in terms of avoiding the "overfished" status. However, the current practice failed to reach the maximum average of the annual yields and led to larger uncertainty in the annual yields.

• 품질경영학회지
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• 제18권2호
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• pp.18-24
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• 1990

The location of inspection stations is a significant component of production systems. In this paper, a prototype expert system is designed for deciding the optimal location of inspection stations. The production system is defined as a single channel of n serial operation stations. The potential inspection station can be located after any of the operation stations. Nonconforming units are generated from a compound binomial distribution with known parameters at any given operation station. Traditionally Dynamic programming, Zero-one integer programming, or Non-linear programming techniques are used to solve this problem. However a problem with these techniques is that the computation time becomes prohibitively large when t be number of potential inspection stations are fifteen or more. An expert system has the potential to solve this problem using a rule-based system to determine the near optimal location of inspection stations. This prototype expert system is divided into a static database, a dynamic database and a knowledge base. Based on defined production systems, the sophisticated rules are generated by the simulator as a part of the knowledge base. A generate-and-test inference mechanism is utilized to search the solution space by applying appropriate symbolic and quantitative rules based on input data. The goal of the system is to determine the location of inspection stations while minimizing total cost.

• 한국지역지리학회지
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• 제14권2호
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• pp.93-104
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• 2008

이 논문은 연변지역의 농업 변화과정을 일제시기, 사회주의시기, 개혁개방시기 등 3개시기로 나누고 각 시기 연변지역의 농업이 외부환경의 변화에 따라 어떻게 시계열적으로 변화 발전되어 왔는지에 대해 살펴보았다. 그 결과를 요약하면 다음과 같다. 첫째, 일제시기 연변의 농경지는 이민정책, 자작농창정, 집단부락건설 등의 형식으로 일제의 수중에 집중되면서 자신들의 전쟁 수요와 국내 수요에 따라 농작물 재배를 통제할 수 있고 또한 농작물을 마음대로 약탈 할 수 있는 기반을 마련하여 전형적인 주변부 특징을 띠고 있었다. 둘째, 사회주의 시기 연변지역은 농촌의 인민공사화를 실현함에 따라 토지는 전부 국가소유로 되었다. 이와 같은 토지의 국가 소유는 농업생산에 있어 강력한 국가의 개입을 가능케 하였다. 그리하여 당시 계획경제체제 하에서 농업생산은 시장 논리에 의해 좌우된 것이 아니라 식량생산만을 중요시하는 '이양위강(以糧爲綱)'정책의 영향으로 농업 내부에 있어 경작업만 중요시하고 경작업 내부에서도 식량생산만을 중요시 하여 풍부한 자연자원을 효과적으로 이용할 수 없게 되었다. 셋째, 개혁개방 이후 농촌에서 호도거리책임제를 실시함에 따라 농민들이 토지를 장기간 임대할 수 있게 되어 농민들의 생산의지가 크게 고양되었다. 게다가 사회주의 상품경제에서 시장경제체제로 전이함에 따라 시장의 수요에 따라 농작물을 재배할 수 있게 되었다. 그리하여 연변지역의 농업은 전통적인 식량작물 생산 위주에서 점차 다각화 방향으로 발전하게 되었다.

• Asian-Australasian Journal of Animal Sciences
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• 제18권5호
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• pp.723-727
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• 2005

Ghrelin is a novel growth-hormone-releasing acylated peptide, which has been purified and identified in rat stomach. In the present study, the full-length sequence of bovine ghrelin cDNA was cloned by RT-PCR. The bovine ghrelin cDNA sequence derived in the present study included a 348 bp open reading frame and a 137 bp 3'UTR. The putative amino acid sequence of bovine prepro-ghrelin consisted of 116 amino acids, which contained the 27-amino acid ghrelin. The sequence analysis of the bovine ghrelin gene revealed that an intron existed between Gln$^{13}$ and Arg$^{14}$ of ghrelin. This exon-intron boundary matched the GT-AG rule of the splicing mechanism. Compared with rats, which have two tandem CAG sequences in the 3'end of intron, bovine ghrelin genome has only one CAG sequence. Therefore, although rats can produce 28 amino acid-ghrelin and 27 amino acid-des-Gln$^{14}$-ghrelin by alternative splicing, ruminant species, including bovines, might be able to produce only one type of ghrelin peptide, des-Gln$^{14}$-ghrelin. The influence of aging on plasma ghrelin concentration was also examined. Plasma ghrelin concentration increased after birth to approximately 600 days of age, and then remained constant.

• 정보처리학회논문지B
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• 제10B권7호
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• pp.757-768
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• 2003

본 논문에서는 가중 퍼지 Pr/T 네트에 기반을 둔 규칙기반시스템을 위한 가중 퍼지 추론알고리즘을 제안한다. 이때 퍼지 생성규칙의 확신도, 규칙에 나타나는 술어의 진리값과 술어의 중요도를 나타내는 가중값을 퍼지 숫자로 표현한다. 제안한 추론알고리즘은 퍼지 생성규칙에 있는 술어의 중요도에 따라 부여한 가중값을 이용하여 추론하기 때문에 $\circled1$ 술어의 가중값 없이 퍼지 생성규칙의 확신도만을 기반으로 단순하게 min과 max 연산을 하거나[10], $\circled2$ 술어의 가중값 없이 퍼지 생성규칙에 있는 퍼지 개념에 따라 믿음값 평가함수로 퍼지 생성규칙의 믿음값을 평가하는[12] 방법보다 더 유연하고 사람의 직관과 추론에 가깝다.

• KDI Journal of Economic Policy
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• 제36권4호
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• pp.1-32
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• 2014

주파수와 같이 매우 희소한 경제적 자원을 배분하는 경우 경매는 배분적 외부성으로 인하여 비효율적 결과를 낳을 수 있다. 경매수입이 아닌 사회후생을 기준으로 하면, 경매를 통한 배분은 경매참여자가 2인일 때에도 비효율적일 수 있다. 이는 2위 기업이 주파수를 더 효율적으로 활용할 수 있다 하더라도 이를 통해 얻는 이익은 크지 않은 반면에 선도기업이 시장을 잠식당함으로써 입는 손실이 클 때 발생한다. 2-경기자 호텔링 모형을 사용하여 분석한 결과, 2위 기업의 입찰가에 어떠한 승수를 곱함으로써 2위 기업을 경매에서 유리하게 만들 경우 경매를 통한 배분 결과가 파레토 개선된다. 승수는 시장점유율을 바탕으로 구할 수 있으며 시장점유율 격차가 클수록 높다.

• 산업경영시스템학회지
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• 제38권4호
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• pp.159-167
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• 2015

We consider a wafer lot transfer/release planning problem from semiconductor wafer fabrication facilities to probing facilities with the objective of minimizing the deviation of workload and total tardiness of customers' orders. Due to the complexity of the considered problem, we propose a two-level hierarchical production planning method for the lot transfer problem between two parallel facilities to obtain an executable production plan and schedule. In the higher level, the solution for the reduced mathematical model with Lagrangian relaxation method can be regarded as a coarse good lot transfer/release plan with daily time bucket, and discrete-event simulation is performed to obtain detailed lot processing schedules at the machines with a priority-rule-based scheduling method and the lot transfer/release plan is evaluated in the lower level. To evaluate the performance of the suggested planning method, we provide computational tests on the problems obtained from a set of real data and additional test scenarios in which the several levels of variations are added in the customers' demands. Results of computational tests showed that the proposed lot transfer/planning architecture generates executable plans within acceptable computational time in the real factories and the total tardiness of orders can be reduced more effectively by using more sophisticated lot transfer methods, such as considering the due date and ready times of lots associated the same order with the mathematical formulation. The proposed method may be implemented for the problem of job assignment in back-end process such as the assignment of chips to be tested from assembly facilities to final test facilities. Also, the proposed method can be improved by considering the sequence dependent setup in the probing facilities.

• 한국정밀공학회지
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• 제33권10호
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• pp.851-856
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• 2016

Planetary gear systems have several advantages over traditional gearboxes with parallel axis gear shafts. The planetary gearbox arrangement also creates greater stability due to the even distribution of mass and increased rotational stiffness. However, gears in planetary gear systems occasionally have a short-life due to wear and breakage by repetitive load during operation time. In this study, we evaluated variables of the strength design for each part and conducted structural analysis of seven cases of the planetary gear system. The result of structural analysis was applied to shape optimization method and obtaining the weight lightening designed value. Subsequently, the planetary gear system was performed to ensure the durability of gears during operation time with miner's rule.

• 한국시뮬레이션학회논문지
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• 제8권4호
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• pp.73-87
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• 1999

Order Review/Release (ORR) System is the linkage between planning system and actual production. Reduction of the waiting time on the machines, work in process and lead time variation may be achieved by adopting ORR strategies. But researchers on the ORR do not agree on the effectiveness of ORR. Some say that the overall system flow time may be increased if ORR is adopted, but others say that ORR can reduce work in process, flow time and variation of flow time. The objective of this research is to clarify under what environments order release strategy is effective. Simulation study was conducted in a hypothetical job shop. The experimental results show that dispatching rule is much more important than ORR is in controlling the shop floor. But the results indicate that ORR can reduce mean shop flow time, average work in process and variation of shop flow time under such environments where utilization level is high and planned order is weekly released to the order pool. And the results also show that the effect of plan smoothing on the ORR is insignificant, which is inconsistent with the results of the previous researches.

• 한국정밀공학회지
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• 제18권1호
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• pp.63-73
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• 2001

This paper presents a process and operation planning system with an NC code post-processor for effective machining of press dies for production of cars. Based on the machining features, major parts of press dies are categorized into 15 groups and a standard process plan is defined for each group. The standard process plan consists of a series of processes where a process is defined as a group of operations that can be done with one setup. Details such as cutting tools, cutting conditions, and tool paths are decided at the operation planning stage. At the final stage of process and operation planning, the NC code post-processor we developed adjusts feedrates along the tool path to reduce machining time. The adjustment rule is selected based on the metal removal rate estimated by virtually machining with virtual cutting tool.