• 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.

• 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.

• 수산경영론집
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• 제42권3호
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• pp.31-39
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• 2011

This paper attempts to extend such analysis to the rather more difficult problem of optimal management of transnational fish stocks jointly owned by two countries. Transboundary fish such as Mackerel creates an incentive to harvest fish before a competitor does and leads to over-exploitation. This tendency is especially poignant for transnational stocks since, in the absence of an enforceable, international agreement, there is little or no reason for either government or the fishing industry to promote resource conservation and economic efficiency. In the current paper I examine a game theoretic setting in which cooperative management can provide more benefits than noncooperative management. A dynamic model of Mackerel fishery is combined with Nash's theory of two countries cooperative games. A characteristic function game approach is applied to describe the sharing of the surplus benefits from cooperation and noncooperation. A bioeconomic model was used to compare the economic yield of the optimal strategies for two countries, under joint maximization of net benefits in joint ocean. The results suggest as follows. First, the threat points represent the net benefits for two countries in absence of cooperation. The net benefits to Korea and China in threat points are 2,000 billion won(${\pi}^0_{KO}$) and 1,130 billion won(${\pi}^0_{CH}$). Total benefits are 3,130 billion won. Second, if two countries cooperate one with another, they reach the solution payoffs such as Pareto efficient. The net benefits to Korea and China in Pareto efficient are 2,785 billion won(${\pi}^0_{KO}$) and 1,605 billion won(${\pi}^0_{CH}$) or total benefits of 4,390 billion won : a gain of 1,260 billion won. Third, the different price effects under the two scenarios show that total benefit rise as price increases.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.1523-1523
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• 2001

The wine industry requires practical methods for objectively measuring the composition of both red wine grapes on the vine to determine optimal harvest time; and of freshly harvested grapes for efficient allocation to vinery process streams for particular red wine products, and to determine payment of contract grapegrowers. To be practical for industry application these methods must be rapid, inexpensive and accurate. In most cases this restricts the analyses available to measurement of TSS (total soluble solids, predominantly sugars) by refractometry and pH by electropotentiometry. These two parameters, however, do not provide a comprehensive compositional characterization for the purpose of winemaking. The concentration of anthocyanin pigment in red wine grapes is an accepted indicator of potential wine quality and price. However, routine analysis for total anthocyanins is not considered as a practical option by the wider wine industry because of the high cost and slow turnaround time of this multi-step wet chemical laboratory analysis. Recent work by this ${group}^{l,2}$ has established the capability of near infrared (NIR) spectroscopy to provide rapid, accurate and simultaneous measurement of total anthocyanins, TSS and pH in red wine grapes. The analyses may be carried out equally well using either research grade scanning spectrometers or much simpler reduced spectral range portable diode-array based instrumentation. We have recently expanded on this work by collecting thousands of red wine grape samples in Australia. The sample set spans two vintages (1999 and 2000), five distinct geographical winegrowing regions and three main red wine grape varieties used in Australia (Cabernet Sauvignon, Shiraz and Merlot). Homogenized grape samples were scanned in diffuse reflectance mode on a FOSE NIR Systems6500 spectrometer and subject to laboratory analysis by the traditional methods for total anthocyanins, TSS and pH. We report here an analysis of the correlations between the NIR spectra and the laboratory data using standard chemometric algorithms within The Unscrambler software package. In particular, various subsets of the total data set are considered in turn to elucidate the effects of vintage, geographical area and grape variety on the measurement of grape composition by NIR spectroscopy. The relative ability of discrete calibrations to predict within and across these differences is considered. The results are then used to propose an optimal calibration strategy for red wine grape analysis.

• 한국수산과학회지
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• 제44권4호
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• pp.359-365
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• 2011

This study was conducted to investigate the production, elver stocking, rearing facilities and rearing method of eel culture to determine aquaculture management conditions for optimal rearing of eel Anguilla japonica. The production of eel culture was evaluated by the proportion of eels from the main inland fin fish species production in Korea. Elver stocking was assessed by the elver stocking densities of pond and recirculation culture. Rearing facilities were investigated according to the rearing tank size proportion of the pond and recirculation culture. We selected sample farms by region and by size. We visited sample farms and recorded the number of elvers stock for pond area, size of tanks, feed and feed quantity, and the size and number of harvest eels. The production capacity of Jeollanam-do and Jeollabuk-do were 71.9% and 21.3% respectively. This production quantity represented 93.2% of the total Korean eel production quantity. In Jeollanam-do, there are 236 eel farms, 202 pond farms, and 34 recirculation aquaculture facilities. The elvers' first density data by each aquaculture method revealed that elvers' first density varied more in recirculation system farms, as compared to pond aquaculture. In intensive pond farms, the elvers' first density decreased as the size of farm increased. There was a correlation between the size of tank(x) and the facility of a water wheel for dissolved oxygen in pond culture systems(y=0.022x-0.494; $R^2$=0.860). Another strong correlation was found between the weight of eel(x) and eel density(y) in pond culture systems(y=283.5x-0.27; $R^2$=0.992). Finally, there was a strong correlation between the length of eel(x) and the weight of eel(y) in intensive pond culture(y=0.0005x-3.2783; $R^2$=0.9775). The final survival rate did not differ significantly among pond sizes and culture types.

• 생물환경조절학회지
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• 제20권4호
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• pp.326-332
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• 2011

본 연구는 주요 봄배추 품종에 대하여 야간 저온처리가 생육 및 추대에 미치는 영향을 평가하여 봄배추 육묘 시 안정 환경관리의 기준을 설정하고자 수행하였다. 시험에는 '춘광' 등 주요 봄배추 7품종을 이용하였으며 생육상을 이용하여 야간에 $5^{\circ}C$ 및 $10^{\circ}C$의 저온처리를 실시하였다. 처리시점은 파종 후 5, 10 및 15일째부터, 처리기간은 각 처리시작 시점부터 5, 10 및 15일간으로 각각 조합 처리한 후 포장에서의 생육 및 추대 여부를 조사하였다. 시험에 사용한 모든 품종에 있어서 최대 $5^{\circ}C$에서 15일간의 야간 저온처리에 의하여 유묘생육은 크게 저하하였으나 재배기간 동안 추대는 일어나지 않았으며 정식 90일 후 정상적인 수확이 가능하였다. '춘광' 품종에 대한 육묘기 야간 저온처리 개시 시점과 처리기간의 복합 처리 결과, 낮은 온도조건으로 어린식물체의 상태에서 처리기간이 길어짐에 따라 묘 생체중이 대조구에 비해 최대 59.3%까지 크게 감소되었다. 반면 저온처리 후 생육이 극도로 억제된 묘는 정식 후 생육이 다시 회복되어 수확시 생체중은 대조구 대비 72.3~110%의 범위를 나타내어 모든 처리구에서 정상적인 수확이 가능하였다. 또한 $5^{\circ}C$ 또는 $10^{\circ}C$에서 최대 15일간의 육묘기 야간저온 처리에 의한 추대 현상은 관찰되지 않았다. 본 연구를 통해 봄배추 주요 품종에 대한 육묘기 야간 저온이 생육에 미치는 영향은 제한적으로 나타났다. 육묘기간 동안 단기간 $5^{\circ}C$ 이하의 저온에 노출된 경우에도 주간의 적정한 온도관리와 포장에서의 기후조건에 따라 추대를 지연시키거나 방지시킬 수 있을 것으로 생각된다.

• Journal of Chest Surgery
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• 제36권6호
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• pp.384-390
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• 2003

1966년 Ross와 Sommerville에 의해서 폐동맥 판 폐쇄 환자의 우심실 유출로 재건에 동종 대동맥 판막 도관 이 처음으로 이식되어 보고된 이후 최근까지 다양한 복잡 선천성 심장기형의 완전 교정술에 꾸준히 사용되어 오고 있다. 이렇게 축적된 경험에 힘입어, 국내에서도 여러 병원에서 적극적으로 사용하고 있지만 아직 임상 경험 및 결과에 대한 국내의 보고가 드물어 본원의 경험을 공유하고자 한다. 대상 및 방법: 1996년 1월부터 2001년 12월까지 우심실 유출로에 심장 외 판막 도관(extra-valved conduit)으로 동종이식편을 사용한 예가 27예 있었는데, 이들 중 1년 이상 추적 관찰이 가능한 22명의 환자들을 대상으로 하였다. 환자의 연령의 중앙값은 16개월(9일~18세)이었다. 수술시 진단은 심실 중격 결손에 폐동맥 판막 폐쇄가 동반 된 환자가 13예로 가장 많았고, 그밖에 총 동맥간 3예, 대 혈관 전위증 혹은 수정 대 혈관 전위증에 우심실 유출로의 폐쇄가 동반된 예가 각각 3예씩 있었다. 이식 편의 크기는 15~26 mm로 다양하였으며, 평균 18$\pm$3.82 mm였다. 추적 관찰 기간의 중앙값은 48개월(기간 12~80.4개월)이었다. 결과: 이식 편 자체의 변성으로 인한 재수술은 없었으나, 말단 폐동맥의 협착으로 인한 이식 도관의 비정상적 확장 및 폐동맥 판막의 역류, 우심실의 기능부전으로 이식 도관의 교체가 필요했던 환자가 1명 있었다. 추적 관찰 시 시행한 심초음파상, 유의한 폐동맥 판막의 협착을 보인 환자가 1명 있었고 폐동맥 판막의 역류가 관찰된 환자가 3명 있었는데, 각각 3~6개월, 1년, 2년에 중등도 이상으로 진행하였다. 그리고, 2명의 환자에서 문합 부분의 경미한 석회화가 관찰되었는데, 모두 대동맥 판막 도관을 이식 받은 환자였다. 결론: 성인과 달리, 소아에서의 우심실 유출로의 재건에 있어서는 아직은 이상적인 대치물이 없다. 본원에서는 초저온 냉동 보관한 동종 판막 도관을 적극적으로 사용하여, 중, 단기 추적 관찰상 비교적 좋은 결과를 보이고 있다. 하지만 향후 동종이식편의 수명에 관련되는 요인들에 대한 면밀한 연구를 통하여, 동종이식편의 채취 및 보관, 사용 등에 대한 기준을 재정립하는 것이 중요할 것이다.