• East Asian mathematical journal
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• 제34권5호
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• pp.683-691
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• 2018

We consider an optimal control problem for an impulsive stage-structured model involving ordinary differential equations with impulsive values of initial conditions in the next year. The main goal is to maximize a profit of the catch of Pacific cod in the South Korea through optimal harvest strategy as a control of adult cod. We established necessary conditions for the optimal harvest control using idea of Pontryagin's maximum principle. The optimal harvest strategy is to numerically solve the equation by using an iterative method with the Runge-Kutta method. Finally, we compare a monthly average of fishing mortality of Pacific cod from 2013 to 2017 with monthly fishing mortality for result obtained optimal harvest strategy.

• 한국산림과학회지
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• 제101권1호
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• pp.96-103
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• 2012

본 연구에서는 산림수확계획 수립에 있어 벌채지 선정에 효과적으로 활용될 수 있는 수확분배시뮬레이션 모델의 도입을 위한 사례연구를 수행하였다. 이를 위해 Gustafson과 Crow가 개발한 HARVEST를 산림수확 공간분배 모델로 선정하고 국립산림과학원의 광릉시험림을 대상으로 벌채구획의 면적제한, 벌채지 선정방법, 및 벌채지 연접제한과 같은 기본적인 산림수확 경영방침을 적용하여 모델의 적용성을 검토하였다. 연구결과 벌채 구획의 면적제한 조건의 경우 허용벌채면적이 커질수록 벌채구획의 수는 적어지고 벌채구획간의 거리는 멀어지는 것으로 나타났다. 또한 임의산개형, 군상형 군상택벌형 및 영급순 등 벌채임분의 선정방법을 달리하여 수확 시뮬레이션에 적용한 경우 군상택벌형을 제외하고 벌채구획의 크기와 개소 수는 비슷한 경향을 나타내었으나 벌채지간 거리에서 차이를 나타내었다. 벌채지의 연접제한은 이미 벌채된 임분 주변에서의 벌채를 제한하므로 벌채구획의 수를 증가시키는 효과를 나타냈다. 이상의 연구결과를 종합한 결과 HARVEST는 산림수확을 수행하는데 있어 다양한 경영목표에 따라 벌채구획의 수와 공간분포의 정도를 조절할 수 있는 효과적인 도구로 평가되었다.

• Journal of Biosystems Engineering
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• 제20권1호
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• pp.22-35
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• 1995

Pepper is the most important horticultural plant in Korean farm. Pepper harvesting has been known to be the most difficult process in pepper cultivation so that demand for mechanization is strong. In a research to develop a pepper harvesting machine performance and capacity of the harvester should be determined based on both economical feasibility and machine design concept. In order to accomplish an economical analysis of the pepper harvester, a mathematical model for comparing manual harvesting cost to machine harvest cost was developed. Validity of the model depends on the data used in the model. Economical information for the model variables was acquired from the result of farm survey on pepper cultivation technique and economics of pepper farmer. Technical information on pepper harvester were also collected through literature review and analyzed. Based on the economical analysis and synthesis of the technical information on pepper harvesters, its performance and capacity were determined. The operating performances of the harvester such as cutting, conveying, flipping, pepper removing and post-processing (sorting) were determined. Daisy capacity of the machine was determined to be 0.41 ha. A pepper harvester with the suggested capacity was economically feasible if the price of pepper harvester, pepper recovery ratio and service life of harvester were about 6 million won, 80%, and 4 years, respectively.

• Fisheries and Aquatic Sciences
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• 제26권10호
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• pp.617-627
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• 2023

Harvest control rules have been recently developed for some fisheries in Indonesia, including grouper fisheries, and are expected to reverse the trend of declining stocks. One of the proposed options of the harvest control rules is to implement the catch size limit. The catch size limit approach, however, is challenging, unless it is supported also with strong fisheries surveillance, law enforcement, and innovation. The catch size limit approach can be done by implementing changes in fishing methods and gear, including the application of different hook sizes in the hook and line fishing gear. This study examines the impact of different hook sizes on the length at first capture (Lc) and on the bell-shaped maximum selectivity using various selectivity models of the two targeted grouper species (Plectropomus leopardus and Plectropomus maculatus) in the Saleh bay, West Nusa Tenggara, Indonesia. We found that increasing hook size influences the grouper's catch size, increasing the Lc and the bell-shaped maximum selectivity of both species. Based on our findings, hook size can be used as one of the practical tools for grouper management measures, as part of harvest control rules to improve grouper stock in Indonesia.

• 통상정보연구
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• 제13권3호
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• pp.511-541
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• 2011

본 연구에서는 앞으로 있을 한 중 FTA협상 추진 전략을 중국의 낮은 수준의 FTA 체결 선(先)제의에 대한 우리나라의 최적 대응전략 측면에서 고찰하였다. 국제협상 분석 게임모델 중 비협조게임의 기본 모형인 죄수의 딜레마 게임을 기본 틀로 하여 Putnam의 2단계 게임 론을 활용하여 결론을 도출하였다. 향후 한 중 FTA 추진의 전략적 기본원칙은 정부가 주장하는 높은 관세양허 수준의 포괄적 FTA보다는 비록 경제적 효과가 다소 떨어지더라도 가능한 빠른 시일 내 '중간 수준'의 FTA(포괄적이나 전반적으로 낮은 관세양허 방안)를 시작하는 정책을 추진함이 바람직 할 것으로 결론지었다. 이러한 관점에서 한 중 양국이 상대국으로부터의 수입액 중 일정 비율, 가령 70-80%에 해당하는 품목에 대해 협상개시와 함께 관세를 내리는 조기수확 프로그램(EHP: Early Harvest Program)을 활용하는 전략도 한 방법이 될 것이다.

• 기록학연구
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• 제35호
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• pp.133-160
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• 2013

네트워크 및 정보통신기기가 발전함에 따라 웹이 우리 일상에 미치는 영향력은 점점 더 증가하고 있다. 또한 웹 공간에서 생성되는 정보도 각 시대를 반영하는 중요한 기록물로서 그 중요성이 나날이 커지고 있다. 이에 따라 웹 정보들을 아카이빙 할 수 있는 표준화된 방법이 요구되고 있으며, 그중 한 가지가 자동화된 수집도구를 사용하여 주기적으로 수집하는 스냅샷 전략이다. 하지만 스냅샷 전략은 주기적으로 웹 콘텐츠를 수집하기 때문에 동일한 웹 콘텐츠가 중복 수집되는 문제가 있다. 또한 웹 환경에서 구현되는 복잡한 기술로 인하여 의미 없는 웹 콘텐츠가 수집될 가능성도 배제할 수 없는 실정이다. 본 논문에서는 공공기관 홈페이지 웹 콘텐츠를 스냅샷 전략으로 수집한 사례 분석을 통해서 원격 수집할 때 발생할 수 있는 콘텐츠 중복 문제들을 살펴보고, 기술 측면에 해결책을 제시하고자 한다.

• 한국가금학회지
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• 제45권1호
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• pp.1-15
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• 2018

Salmonella infections in livestock industry cause various problems such as worsening animal welfare and productivity, damaging consumer confidence in the food safety of animal products. Chicken meat and eggs are known as major source of pathogen causing human foodborne infections. Therefore food safety concerns have prompted the poultry producers and governments to introduce the strategy and regulation to control these pathogens. Salmonella can persist for long periods of time in a wide range of spaces including feed bin, feed processing facilities, poultry farm, slaughterhouse, processing plants, etc. For the effective and constant Salmonella control, combination of pre-harvest, harvest and post-harvest measures should be considered comprehensively. The control measures would be most effective at farm level where the contamination initiates. Transmission of pathogen from feed origin to the live poultry and finally to the products was proven already. To control bacteria in the feed ingredients and formula feed, thermal processing, irradiation or chemical treatment may be applied. Chemical treatments to inhibit Salmonella in the feed involve the use of products containing organic acids, formaldehyde, or a combination of such compounds. However, recontamination which might occur during storage and transport process and/or by other various factors should always be under control and eliminated. Feed additives used to control Salmonella in birds' gastrointestinal track can be of various types, including prebiotics, probiotics, organic acids and bacteriophages. Although their mode of action varies, they ultimately inhibit the colonization of Salmonella in the gut and improve the performance of birds. This review describes the strategies that could be adapted to the management of feedstuffs and the use of feed additives in pre-harvest stage to control Salmonella contamination in poultry farming.

• 수산경영론집
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• 제45권1호
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• pp.109-119
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• 2014

This study aimed to examine the applicability of a portfolio approach to the ecosystem-based fisheries management targeting the large purse seine fishery. Most fisheries are targeting multispecies and species are biologically and technically interacted each other. It enables a portfolio approach to be applied to find optimal production of each species through expected returns and risk analyses. Under specific assumptions on the harvest quota by species, efficient risk-return frontiers were generated and they showed a combination of optimal production level. Comparisons between portfolio and actual production provided a useful information for targeting strategy and management. Results also showed the possibility of effective multispecies fisheries management by imposing constraints on each species such as total allowable catch quotas.

• The Korean Journal of Physiology and Pharmacology
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• 제12권6호
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• pp.307-314
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• 2008

Retinal prostheses are being developed to restore vision for the blind with retinal diseases such as retinitis pigmentosa (RP) or age-related macular degeneration (AMD). Among the many issues for prosthesis development, stimulation encoding strategy is one of the most essential electrophysiological issues. The more we understand the retinal circuitry how it encodes and processes visual information, the greater it could help decide stimulation encoding strategy for retinal prosthesis. Therefore, we examined how retinal ganglion cells (RGCs) in in-vitro retinal preparation act together to encode a visual scene with multielectrode array (MEA). Simultaneous recording of many RGCs with MEA showed that nearby neurons often fired synchronously, with spike delays mostly within 1 ms range. This synchronized firing - narrow correlation - was blocked by gap junction blocker, heptanol, but not by glutamatergic synapse blocker, kynurenic acid. By tracking down all the RGC pairs which showed narrow correlation, we could harvest 40 functional connectivity maps of RGCs which showed the cell cluster firing together. We suggest that finding functional connectivity map would be useful in stimulation encoding strategy for the retinal prosthesis since stimulating the cluster of RGCs would be more efficient than separately stimulating each individual RGC.

• 한국식품저장유통학회:학술대회논문집
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• 한국식품저장유통학회 2003년도 제23차 추계총회 및 국제학술심포지움
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• pp.51-70
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• 2003

In recent years, Korean rice must compete with the rice of advanced countries under Doha Development Agenda(DDA) and free Trade Agreement(FTA). Therefore we should find more active and positive solution in rice industry according to the inncreasing power of international pressure. Increasing rice production was the most important policy during the past food-deficient days, but recently, with overproduction of rice, various circulation system by the brand(price)-differentiation should be settled in a recent market of Korea. Nowadays, some advanced rice farmers and Rice Processing Complex(RPC) managers developed new brands of rice with high-quality, adding healthy materials and environment-friendly farming methods. Therefore, the future strategy of making a new brand rice should be planned including selection of rice variety, cultural and post-harvest techniques, circulation and processing methods to compete against foreign rice. And environment-friendly farming is also recommendable for food safety and differentiate from imported rice. For the purpose of successful brand-rice, the following points might be considered. Firstly, selection of good quality rice and continual development of good variety must be conducted for the differentiation of Korean rice from foreign rice. Secondly, a special contract between producer and consumer with functional-rice, organic filming-rice, specific-rice will be recommendable. Thirdly, improvement of post-harvest management and milling system are necessary for the production of differentiated-rice. Fortunately, standard of inspection, rules of description for brand-rice must be developed by a more scientific examination in order to settlement of trust for consumer. Finally, provincial or regional-representative brand rice must be settled and conducted for the development of agreement market system between producer and consumer.