• 농촌지도와개발
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• 제17권3호
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• pp.527-548
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• 2010

The objective of this study is to suggest the developmental tasks for the successful fostering the Farmer's Study Group which have been guided by the agricultural extension work since 1994 in Korea. The 3,278 farmers study groups with 148,420 memberships have been organized in field of grains, cash crop, horticulture, livestock, improving living conditions, food processing and so on. Although the number of study groups have rapidly expanded, there also are tasks to be secured for their successful development in terms of (a) desirable phase of the study groups and goals of its fostering, (b) managements / administration of them, (c) long-term tasks to be reviewed. With regard to the desirable phase of the study groups and goals of its fostering, they should secure differential mission and the way of works compare to the other farmer's groups. Also, there should be consensus on the proper number of study groups to be fostered with a agricultural technical center at local level. With regard to the managements / administration of the study groups, there should be the different support, assistance and guidance according to the developmental level of the groups. For these, there should be evaluation works on the groups, and guidance manuals for the extension workers. Also extension works should facilitate the establishment of networks among groups over the counties. Finally, to establish the nationwide association in hierarchy and to make the cooperative works with similar farmer's group, doing the value-added activities rather than mere information exchange, and the introduction of capacity building programs for the extension workers are long-term tasks needed to review for the successful fostering study groups.

• 한국유기농업학회지
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• 제19권spc호
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• pp.263-266
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• 2011

Crop protection strategies in organic horticulture aim to prevent insect pest and plant disease problems through utilization of non-chemical based control means. In order to develop a model for management of plant diseases and insects in organic cucumber cultivation, we compared efficacies between chemical pesticide spraying system and biological control means in semi-forcing and retarding cucumber cultivation during 2005 and 2006. Conventional chemical spray program using various chemical pesticides was applied 5 - 10 days intervals, while two different non-chemical pesticide application programs using two formulated biopesticides Topseed$^{TM}$ and Q-fect$^{TM}$, Suncho$^{TM}$, and Sangsungje$^{TM}$ (biocontrol agents 1) and using egg-yolk and cooking oil(EYCO), Bordeaux mixture, Suncho$^{TM}$, and Sangsungje$^{TM}$ (biocontrol agents 2) were applied 5 - 7 days intervals during entire cucumber cultivation period. Efficacy of both biocontrol agents programs was effective to comparable to conventional chemical pesitice spray program to control plant diseases such as powdery mildew and downy mildew as well as insect pests such as aphids and thrips which are known as major threats in cucumber organic cultivation. In this study, we established and evaluated an effective and economic crop protection strategy using various biological resources can be used to control plant diseases and pests simultaneously in organic cucumber cultivation field.

• 수산해양기술연구
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• 제57권4호
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• pp.271-282
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• 2021

This study aims to understand the opening efficiency of the finless porpoise escape guide net by the type of extension net that is the part to which the escape guide net is attached in stow net. To this end, extension nets were manufactured in full size and the net mouth area and towing tension were investigated according to the towing speed (0.2, 0.4, 0.6 and 0.8 m/s) and the type of extension net (25 mm net and raschel net) in the water tank. As a result, the net mouth area of the guide net was larger when the raschel net was used for the extension net than when the 25 mm net was used under all towing speeds. In addition, regardless of the type of extension net, the net mouth area reached about 80% of the maximum value at a towing speed of 0.4 m/s. In the field, fishing operation of stow net is performed only when the current speed is above 0.4 m/s. Therefore, the speed of 0.4 m/s was confirmed as a meaningful value to determine whether it is possible to operate. As a result of analyzing the relationship between the net mouth area of the guide net and the towing tension, it was confirmed that the difference in the net mouth area of the guide net according to the type of the extension net was due to the difference in the solidity ratio.

• 한국전자통신학회논문지
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• 제4권3호
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• pp.197-203
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• 2009

부호이론이나 암호학의 응용분야에 유한체는 매우 중요한 내용이고, 컴퓨터에서의 구현시에는 종규기저를 사용하는 것이 효과적이다. 본 논문에서는 유한체 타입 I 최적정규기저를 가지는 $GF(2^{mk})$는 $GF(2^m)$의 확대체가 된다는 사실을 이용하여 지금까지 알려진 가장 효율적인 Reyhani-Masoleh and Hasan의 곱셈기보다 25%정도 빠른 곱셈기를 소개하려고 한다.

• 응용통계연구
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• 제8권2호
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• pp.133-145
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• 1995

고장원인이 여럿인 수리불가능한 제품에 대하여 사용환경에서 얻어진 고장데이터와 추적조사에 의해 얻어진 설명변수에 관한 데이터를 이용하여 제품의 고장원인별 수명분포를 추정한 배도선 등(1995)의 연구를 수리가능한 제품의 경우로 확장하였다. 수명분포의 모수와 설명변수가 대수선형 관계일 때 비동질성 포아송과정을 이용하여 의사우도함수를 유도하고, 고장원인별 수명이 와이블 분포를 따를 때의 의사 최우추정량과 점근분산을 구하였다. 추적조사 방법으로는 보증기간동안 고장이 발생하지 않은 제품의 일정비율을 추적조사하는 경우와 총 시험제품의 일정비율을 랜덤하게 선택하고 이들 중에서 보증기간동안 한번도 고장이 발생하지 않은 제품에 대해서만 추적조사하는 경우를 고려하였다.

• Kyungpook Mathematical Journal
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• 제49권3호
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• pp.419-424
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• 2009

Let J be the Jacobian variety of a hyperelliptic curve over $\mathbb{Q}$. Let M be the field generated by all square roots of rational integers over a finite number field K. Then we prove that the Mordell-Weil group J(M) is the direct sum of a finite torsion group and a free $\mathbb{Z}$-module of infinite rank. In particular, J(M) is not a divisible group. On the other hand, if $\widetilde{M}$ is an extension of M which contains all the torsion points of J over $\widetilde{\mathbb{Q}}$, then $J(\widetilde{M}^{sol})/J(\widetilde{M}^{sol})_{tors}$ is a divisible group of infinite rank, where $\widetilde{M}^{sol}$ is the maximal solvable extension of $\widetilde{M}$.

• 농촌지도와개발
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• 제4권1호
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• pp.359-370
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• 1997

The Korea National Agricultural College (KNAC) was established as a special three academic years(six semesters) course by the Presidential Act in July 1995 and opened on March 20, 1997. According to the Act, the students of KNAC are granted free boarding in dormitory, full support of educational expenses, and, after completion, exception in military service and financial support for farming, which is their obligation to do for a double period of the total school year. With these institutional favors KNAC is hight expected to bring up promising young farm managers in Korea. However, actual competitive young farm managers are brought up by the well organized education with emphasis on learning by doing approach. With the relation to the education this study was performed to review and examine present situation of faculty organization, facilities and equipments, curriculum including field training in home land and oversea's counties. This study found out that there were undesirable aspects such as unbalanced faculty members among the departments, lack of practice farm land and limited budget in field training, which should be improved to achieve the objectives of KNAC.

• Corrosion Science and Technology
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• 제20권4호
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• pp.169-174
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• 2021

In this study, performance tests, a field evaluation, and a life cycle cost (LCC) analysis for high performance coating systems were conducted to prepare a plan to reduce the cost of maintenance coating and contribute to the service life extension of steel bridges by applying high performance coatings to steel bridges that will be constructed in the future. From the deterioration models based on the field evaluation for chlorinated rubber and urethane topcoat systems, which have been applied often, the mean service lives were derived as 20.8 and 26.6 years, respectively. For the other coating systems that have not been applied in practice, the coordination factors were differentially applied with evaluation items. The most durable coating system was predicted to be thermal spray coating (TSC) primer/epoxy intermediate coat/fluoride resin topcoat, with a predicted value as long as 42.2 years. The LCC analysis indicates that partial application of high performance coating, such as TSC and fluoride resin, to specific parts vulnerable to corrosion and ultraviolet ray (UV) is more advantageous than the use of general coating systems.

• 대한수학회지
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• 제54권2호
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• pp.417-426
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• 2017

We explicitly determine fundamental units and regulators of an infinite family of cyclic quartic function fields $L_h$ of unit rank 3 with a parameter h in a polynomial ring $\mathbb{F}_q[t]$, where $\mathbb{F}_q$ is the finite field of order q with characteristic not equal to 2. This result resolves the second part of Lehmer's project for the function field case.

• 대한수학회지
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• 제39권5호
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• pp.765-773
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• 2002

Let $textsc{k}$＝$F_{q}$(T) be a rational function field. Let $\ell$ be a prime number with ($\ell$, q-1) ＝ 1. Let K/$textsc{k}$ be an elmentary abelian $\ell$-extension which is contained in some cyclotomic function field. In this paper, we study the $\ell$-divisibility of ideal class number $h_{K}$ of K by using cyclotomic units.s.s.