• 한국유기농업학회지
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• 제19권spc호
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• pp.291-294
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• 2011

We studies a model for management of pepper anthracnose based covering method and spraying system in field. 1. Among 82 organic fungicides, 42 materials showed most effective inhibition against mycelia growth of the Colletotrichum acutatum in vitro. 23 formulated biocontrol agents were chosen to control the disease from 42 biocontrol agents in greenhouse. In the end, five kinds (2 plant extracts, 2 biopesiticides, 1 Bordeaux mixture) were selected from 23 materials in the field. 2. The mulching materials of bed covering in fruit season were thin non-woven fabric sheet and black plastic. The use of a fabric sheet was reduced the spread of anthracnose as compared to the plastic covering. 3. The application with the chosen materials was reduced 34% of anthracnose for 7 times sprays to planting 70 days as compared to the untreated control. In yield, nonwoven fabric sheet with formulated biopesticides was increased 17% than black plastic. 4. This result indicated that the developed biocontrol strategy could be an effective and economic crop protection system in organic pepper cultivation field.

• 유기물자원화
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• 제24권1호
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• pp.11-19
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• 2016

농경지에 작물재배를 위한 양분재료의 과다한 투여는 주변 수계로의 양분유출을 증가시킬 수 있다. 고추재배시 사용되는 양분재료는 화학비료, 우분퇴비, 돈분퇴비 등이 대표적이다. 볏짚은 벼 재배의 부산물로 밭 농사에서 잡초발생 억제, 토양수분 보존, 유기물 재료로 널리 사용된다. 본 연구는 노지 고추 재배에서 밭 고랑을 볏짚으로 피복할 때 강우로 발생하는 표면 유출수에 의한 양분유출 특성을 파악하기 위해 수행하였다. 시험구는 양분재료를 기준으로 하여 화학비료, 우분퇴비, 돈분퇴비로 구분하였고 양분투입량은 토양검정 시비량에 준하여 처리하였다. 각각의 시험구는 화학비료 또는 우분퇴비, 돈분퇴비를 시용한 후 볏짚으로 덮은 경우(피복 처리구)와 덮지 않은 경우(무피복구)로 구분하였다. 화학비료 처리구와 우분퇴비 처리구의 볏짚 고랑 피복 처리는 무피복구 보다 T-N (총질소)의 유출이 각각 $1.4kg\;ha^{-1}$, $2.1kg\;ha^{-1}$ 감소하였다. 반면에 화학비료 처리구와 우분퇴비 처리구, 돈분퇴비 처리구의 볏짚고랑 피복 처리는 무피복구 보다 T-P (총인)의 유출이 각각 $2.1kg\;ha^{-1}$, $2.1kg\;ha^{-1}$, $0.2kg\;ha^{-1}$ 증가하였다. 볏짚은 질소 0.4 %, 인산을 0.3 % 함유하고 있고 증류수에 볏짚을 담근 후 3주일 내에 인산 성분이 유출되므로 T-P의 유출은 고랑을 피복한 볏짚에서 기원한 것으로 추정된다. 무피복구에 비하여 고랑 볏짚 피복구는 잡초발생이 줄었다. 그러나 붉은 고추의 수확량은 무피복구와 볏짚피복구 간에 유의한 차이를 나타내지 않았다. 결론적으로, 고추밭 고랑을 볏짚으로 과다하게 피복하면 T-P의 유출을 유발할 수 있으므로 고랑을 피복하는데 적정한 볏짚량을 산정하기 위한 추가적인 연구가 필요하다고 판단되었다.

• 한국토양비료학회지
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• 제44권5호
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• pp.667-673
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• 2011

우리나라 밭은 대부분 산지를 개간하여 조성한 경사 밭으로 작물이 재배되는 여름철 집중강우에 의해 많은 양의 토양이 유실된다. 특히 경사 밭 전면경운에 의한 토양 교란은 무의 발아, 생육초기 단계로 쏟아지는 강우에 표토가 직접 노출되어 토양유실 위험이 가중되고 있다. 본 연구에서는 고랭지 무 재배의 경우 토양피복방법 개선에 의한 토양유실 저감기술을 개발하고자 수행하였다. 토양피복 방법으로 호밀 예취피복, 호밀 초생피복, 흑색비닐멀칭 등 8 처리를 두었으며, 경사 17%내외 무저라이시메타에서 유거수 및 토양유출 특성과 무 생육특성을 평가하였다. 시험결과 호밀예취피복을 포함한 토양피복처리는 유거수 유출량에 있어 ha당 관행 $2,994m^3$인 반면, $773{\sim}2,325m^3$이 유거되어 관행보다 26~78% 수준으로 유거수 량이 감소하였다. 이와 같은 결과는 토양유실량에도 영향을 미쳐 관행 처리구가 ha당 68.2톤인 반면, 호밀예취피복을 포함한 피복처리구는 0.3~16.1톤으로 관행 대비 76~99%에 해당하는 토양유실 경감 효과가 있는 것으로 평가되었다. 무 수확기 수량 구성요소인 근중은 관행의 경우 ha당 92.5톤 수준을 보였는데, 호밀 초생피복은 40.1톤, 벌개미취 초생피복은 46.1톤, 곰취 초생피복은 78.5톤 수준으로 낮은 경향을 보였다. 반면, 호밀 예취피복은 92.9톤, 들묵새 초생피복은 102.6톤, 흑색비닐멀칭은 109.8톤으로 관행과 비슷하거나 오히려 증수되는 결과를 보였다. 본 연구 결과 호밀 예취피복 및 들묵새 초생피복은 무 수량에 는 영향을 미치지 않으면서 토양유실 경감효과가 매우 높아 경사 밭 토양보전기술로 유용하게 적용 되리라 판단된다.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제18권3호
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• pp.261-268
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• 2011

For a compact Hausdorff space X with its p-fold covering map ${\sigma}$, we construct its corresponding topological groupoid ${\Gamma}$, and show that there is a strong relation between the dynamical structures of (X, ${\sigma}$) and the groupoid structures of ${\Gamma}$.

• 한국경영과학회지
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• 제15권2호
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• pp.97-104
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• 1990

The problem is a variation of the weighted set-covering problem (SCP) which requires the minimum-cost cover to be self-covering. It is shown that direct extension of the well-known greedy heuristic for SCP can have an arbitrarily large error in the worst case. It remains an open question whther these exists a greedy heuristic with a finite error bound.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2007년도 추계학술대회 및 정기총회
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• pp.316-321
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• 2007

The hierarchical covering location problem emphasizes the issue of locating of hierarchical facilities in order to maximize the number of customers that can be covered. In the classical HCLP(Hierarchical Covering Location Problem), it is assumed that the customers are covered completely if they are located within a specific distance from the facility, and not covered otherwise. The generalized HCLP is introduced that the coverage of customers is measured to be any real value rather than 0 or 1, where the service level may decrease according to the distance. Mixed integer programming formulation for the generalized HCLP is suggested with a partial coverage of service. Solutions are found using OPL Studio, and are evaluated for various cases.

• 대한가정학회지
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• 제11권1호
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• pp.26-43
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• 1973

This study was carried out on the Sewbility of Urethane Foam usually used as coldproof lining. The Sewability was estimated with the Puckering Grade and Seam Efficiency according to the thicknes of urethane foam, fineness and material of sewing thread, and the sort of covering fabric. The result shows the following ; 1. The thick foam proportinally shows the low Puckering Grade. 2. Effect on the sewability is small in fineness of sewing thread but large in material. Especially silk thread shows the greatest sewability in foam sewing. When the material of covering fabric is same as that of sewing thread (for example ; p/c fabric and p/c thread) the sewability is excellent in special. 3. Taffeta in covering foam is not suitable to foam sewing, satin and twill show superior sewability without reagrd to the thickness of foam. 4. In case of sewing foam covered with tricot, optimum thickness of foam and fineness of sewing thread through pretest must determine. 5. The thicker foam is the better seam efficiency tends, and Seam Efficiency largely effects to the strength of the sewing thread itself. 6. The seam Efficiency can heighten with the strength of sewing thread in proportion to that of covering fabric.

• 아동학회지
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• 제25권1호
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• pp.13-29
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• 2004

In this study of strategies used by young children in solving rectangular covering tasks before they have been taught area measurement, 75 5-, 6-, and 7-year-old children were asked to solve 3 rectangular covering tasks with a moveable unit. Three different sized units (4 cm., 2 cm., and 1 cm. cardboard squares) were provided and the children were asked to work out how many would be needed to cover a drawn rectangle. The resulting 5 developmental levels include incomplete covering, incomplete arrangement, complete covering, estimating, and measuring. Children using more advanced strategies were able to find correct number of units. While the tendency among older children was to use more advanced strategies, even 5-year-olds had an intuitive understanding of rectangular area measurement.

• Journal of applied mathematics & informatics
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• 제22권1_2호
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• pp.435-440
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• 2006

Let G be a simple graph with vertex set V(G) and edge set E(G). A subset S of E(G) is called an edge cover of G if the subgraph induced by S is a spanning subgraph of G. The maximum number of edge covers which form a partition of E(G) is called edge covering chromatic number of G, denoted by X'c(G). It is known that for any graph G with minimum degree ${\delta},\;{\delta}-1{\le}X'c(G){\le}{\delta}$. If $X'c(G) ={\delta}$, then G is called a graph of CI class, otherwise G is called a graph of CII class. It is easy to prove that the problem of deciding whether a given graph is of CI class or CII class is NP-complete. In this paper, we consider the classification of nearly bipartite graph and give some sufficient conditions for a nearly bipartite graph to be of CI class.

• 대한수학회논문집
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• 제18권1호
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• pp.105-115
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• 2003

It is well known that there exists a regular branched covering map from T$^2$ onto $\={C}$ iff the ramification indices are (2,2,2,2), (2,4,4), (2,3,6) and (3,3,3). In this paper we construct (count-ably many) chaotic homeomorphisms induced by hyperbolic toral automorphism and regular branched covering map corresponding to the ramification indices (2,2,2,2). And we also gave an example which shows that the above construction of a chaotic map is not true in general if the ramification indices is (2,4,4) and also show that there are no chaotic homeomorphisms induced by hyperbolic toral automorphism and regular branched covering map corresponding to the ramification indices (2,3,6) and (3,3,3).