• 한국조경학회지
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• 제23권4호
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• pp.12-19
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• 1996

Urban parks, as remnant patches, of two older cities and two new towns can be analyzed by a landscape ecological approach. The index of patch shape, the dispersion of patches, the mean edge length, and the mean patch size of parks of each city are ocmpared. The findings of this study are as follows : 1) The mean edge length of urban parks of older cities is longer than that of new towns : Seoul>Suwon>Bundang>Ansan. 2) The mean patch size of urban parks in Seoul is much greater than those of other cities : Seoul> Ansan>Suwon>Bundang. 3) The index of patch shape of urban parks of older cities is greater than that of new towns : Seoul>Suwon>BundangAnsan. 4) The dispersion of patches is in the order of Bundang >Ansan>Seoul>Suwon. The new towns have relatively even distributions of urban parks than older cities. Further research is required to find out the relationship between the index of patch shape and patch interior dynamics.

• Structural Engineering and Mechanics
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• 제58권2호
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• pp.301-326
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• 2016

An optimization method of patch shape was developed in this study, in order to improve repair of cracked plates. It aimed to minimize three objectives: stress intensity factor, patch volume and shear stresses in the adhesive film. The choice of these objectives ensures improving crack repair, gaining mass and enhancing the adhesion durability between the fractured plate and the composite patch. This was a multi-objective optimization combined with Finite elements calculations to find out the best distribution of patch height with respect to its width. The implementation of the method identified families of optimal shapes with specific geometric features around the crack tip and at the horizontal end of the patch. Considerable mass gain was achieved while improving the repair efficiency and keeping the adhesive shear stress at low levels.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2015년도 춘계학술대회
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• pp.480-481
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• 2015

반파장 길이를 가지는 일반적인 마이크로스트립 안테나는 작은 대역폭 특성을 가진다. 패치 안테나의 모서리를 적절하게 잘라내면 입력 임피던스가 변하여 이에 상응하는 광대역 특성을 얻을 수 있다. 본 논문에서는 2.4GHz ISM 대역에서 동작하는 광대역 마이크로스트립 패치 안테나를 대상으로 패치 안테나의 모서리 단면의 모양에 따른 입력 임피던스의 변화를 통하여 광대역 특성을 얻을 수 있도록 설계하였다.

• 소성∙가공
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• 제24권5호
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• pp.368-374
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• 2015

Hydroforming of a non-axisymmetric thin-walled tubular component with variable cross sections was analyzed. In order to solve the sealing problem which occurred due to the thin and non-axisymmetric shape, the use of a lead patch on the punch, which had been successful in hydroforming of thin tubes, was evaluated. A lead patch was attached to the punch to solve the sealing problem, which was caused by the stress gradient in the non-axisymmetric shape. FEM and experiments were also performed to analyze these sealing problems associated with the punch shape and non-axisymmetric shape. Finally, the lead patch was attached at tube surface where intensive local strain concentration would occur to enhance the hydroformability. These methods were successfully used to fabricate non-axisymmetric thin-walled tubular component with variable cross sections that had previously failed during traditional hydroforming.

• The Korean Journal of Ecology
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• 제22권2호
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• pp.69-77
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• 1999

Secondary vegetation. the holistically integrated system of nature and human being, is the complicated ecosystem that is composed of natural and man-created factors. Understanding the ecological function of secondary vegetation supplies us many important informations for sustainable landscape management and ecological restoration planning. In this research, we tried to examine the shape effect of vegetation patch on early structure of populations of pine and oaks. Moreover. we also tried to clarify the ecological functions of patch edge by exploring the patch effect on germination using patch index. In addition, we present the landscape structure of man -made vegetation of our study area, and setting experimental design of research. Vegetation landscape of study area is typical human disturbed landscape mainly composed of disturbance patches. Vegetation types of graveyard and managed pine forest were controlled by periodically repeated management. However, current seedlings of pine occurred well at both vegetation types. Presence of both saplings were more controlled in managed pine forest (PDM) and graveyard (G) than those of undergrowth (PD) and forest edge (FE) with canopy trees. The number of pine seedlings increased with patch size and patch perimeter. That of oak seedlings was, however, not significantly different. Larger graveyards provided higher light availability for germination of pine seedlings. We think, however, most seedlings of both species in the large sized graveyards without shade will die more easily than that of small sized ones before rainy summer. Relationships between patch shape and germination of two woody species cannot be exactly explained enough yet in these results. More informations on spatial interaction of the total species with differently sized patches are necessary to solve the concept of patch effect on species colonization.

• 한국환경복원기술학회지
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• 제16권4호
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• pp.53-63
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• 2013

The purpose of this study is to analyze impacts of the forest fragmentation caused by development project. Furthermore, to investigate the applicability of landscape indicator when 'Feasibility of forest land conversion to other use' is conducted. The study site was consisted of golf course development and road construction. It is to compare before and after impacts of areal and linear development. As for the methods, selecting landscape indices, clustered into 3 Categories have been utilized. Category I was concerned with 'size of forest patches', II as 'shape of forest patches', and III as 'Core Area' These were calculated by FRAGSTATS, the program for analyzing fragmentation. The results showed that linear development caused more fragmented than areal development projects. Also, patch size, patch shape and core area are related to impacts of development, while Patch size decreased, patch shape and core area increased after development. Therefore, it is necessary to minimize the impacts of forest by considering fragmentation when development project is planned.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.492-495
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• 2003

This paper presents a novel method to reduce the size of microstrip patch antennas using shorting post and spiral shape. The spiral conductor shape of the proposed shorted patch antennas increases the length of the current patch for a given area. Two spiral shaped patch antennas with shorting post operating at 700 MHz bands are investigated experimentally.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 하계종합학술대회 논문집(1)
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• pp.197-200
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• 2004

In this paper, a novel triple-band planar inverted F antenna(PIFA) is proposed. The goal of this paper is to design a small antenna which is operated in triple band. Using T-shape slit and stacked U-shape parasitic patch, good impedance matching is achieved in three band. T-shape slit is inserted on the main patch in order to effectively control the excited patch surface current distributions. The proposed antenna occupies a small volume of $26{\times}9.5{\times}6mm^3$, and the obtained impedance bandwidths cover the required operating bandwidths of the GPS(1565-1585MHz), IMT-2000(1885-2200MHz) and Bluetooth (2400-2484MHz) bands.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2012년도 하계학술대회
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• pp.471-472
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• 2012

The active shape model(ASM) is one of the most popular methods among the shape prior based segmentation methods based on its strong shape constraints using the statistic of shape information which is acquired from the training set. ASM has a few drawbacks, such as, the lack of shape variability, and the sensitivity for false locally searched points. In this paper, we suggest the patch-wise robust ASM to overcome the limitations of the ASM. In addition to the SSM, we introduce the patch-wise SSM, to reduce the shape inflexibility and to search reliable points with the point reliance measurement. The quantitative and qualitative results show the robustmness and the accuracy of the proposed method.

• 대한전자공학회논문지SP
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• 제47권6호
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• pp.75-81
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• 2010

연골 영역화는 골관절염의 진단이나 치료를 위해 중요하지만, 모양이 얇고 의료영상 내에서 주변 조직과의 명암 차이가 크지 않기 때문에 현재까지 전문가가 많은 시간과 노력을 들여 수동으로 하고 있다. 이에 따라 본 논문에서는 3차원 자기공명(Magnetic Resonance : MR)영상 내에서 연골을 자동으로 영역화하는 기법을 제안한다. 제안하는 기법은 전문가에 의해 수동으로 영역화된 소수의 의료영상을 학습 데이터베이스로 하여 우선 연골을 지역적인 부분(local patch)들로 분할하여 부분별로 영역화한 후, 부분별 결과들을 취합하고 정제하는 과정으로 이루어진다. 연골 영역화를 위해 먼저 위치와 밝기 값의 외관정보 (appearance)를 이용하여 뼈와 연골의 경계(bone-cartilage interface)를 추출해내고, 이 경계를 기준으로 하여 연골이 포함되는 주변 영역을 일정한 크기의 패치로 분할한다. 다음, 분할된 패치들의 정보를 이용해, 패치마다 형상 사전지식(shape prior)과 외관 사전지식(appearance prior)을 얻어내고 두 사전지식 간의 비율을 적응적으로 결정한다. 이후 패치마다 사전지식 정보를 통해 에너지를 정의하고, 그래프 컷(Graph Cut) 기법을 통해 이 에너지를 최소화하는 최적의 영역화 결과를 도출한다. 마지막으로 지역적으로 얻어진 영역화 결과들을 모양 사전지식으로 하여 전체적인 연골에 대해 전역적 개선 과정을 수행한다. 실험 결과를 통해 제안하는 자동 영역화 기법으로 임상적으로 유용한 영역화 결과를 얻을 수 있음을 제시한다.