• 산업공학
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• 제23권3호
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• pp.257-263
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• 2010

Taguchi defined a good quality as 'A correspondence of product characteristic's expected value to the objective value satisfying the minimum variance condition.' For his good quality, he suggested Taguchi Method which is called Robust design which is irrelevant to the effect of these noise factors. Taguchi Method which has many success examples and which is used by many manufacturing industry. But Optimal solution of Taguchi Method is one among the experiments which is not optimal area of experiment point. On the other hand, Response Surface Method (RSM) which has advantage to find optimal solution area experiments points by approximate polynomial regression. But Optimal of RSM is depended on initial point and RSM can not use many factors because of a great many experiment. In this paper, we combine the Taguchi Method and the Response Surface Method with each advantage which is called Taguchi-RSM. Taguchi-RSM has two step, first step to find first solution by Taguchi Method, second step to find optimal solution by RSM with initial point as first step solution. We give example using catapults.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 춘계학술대회논문집
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• pp.343-346
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• 2003

In order to construct the extrusion die surface of arbitrarily shaped sections, an automatic surface construction method based on NURBS surface and area mapping method is proposed in the present work. In the present study, a center point for area mapping is determined by introducing the marring concept based on constant area proportionality between original billet and final product. The characteristic points of inlet profile is determined using the traditional area mapping method and the root finding numerical method. The inlet and outlet profiles are precisely described with NURBS curves using the characteristic points of entry and exit sections. For the construction of NURBS surface, an interpolation method for the pre-determined two section curves has been developed to be used in the generation of interior control points and weights. To show the validity of the proposed method, automatic die surface generation is carried out for the several kinds of shaped sections.

• 소성∙가공
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• 제12권4호
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• pp.348-357
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• 2003

In order to construct the extrusion die surface of arbitrarily shaped sections, an automatic surface construction method based on NURBS surface and area mapping method is proposed in the present work. A center point fur area mapping is determined by introducing the mapping concept based on constant area proportionality between original billet and final product. The characteristic points of inlet profile are determined using the traditional area mapping method and the root finding numerical method. The inlet and outlet profiles are precisely described with NURBS curves using the characteristic points of entry and exit sections. For the construction of NURBS surface, an interpolation method for the pre-determined two section curves has been developed to be used in the generation of interior control points and weights. To show the validity of the proposed method, automatic die surface generation is carried out for the several kinds of shaped sections.

• 한국정밀공학회지
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• 제20권10호
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• pp.208-217
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• 2003

In order to construct the extrusion die surface of T -shaped sections, an automatic surface construction method based on NURBS surface and area mapping method is proposed in the present work. In the present study, a center point for area mapping is determined by introducing the mapping concept based on constant area proportionality between original billet and final product. The characteristic points of inlet profile are determined using the traditional area mapping method and the root finding numerical method. The inlet and outlet profiles are precisely described with NURBS curves using the characteristic points of entry and exit sections. For the construction of NURBS surface, an interpolation method for the pre-determined two section curves has been developed to be used in the generation of interior control points and weights. To show the validity of the proposed method, automatic die surface generation is carried out for the T-shaped section and T-shaped section with rounded corners.

• 한국지역지리학회지
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• 제10권2호
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• pp.389-406
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• 2004

최근 지역 연구의 활성화와 더불어 지역 자료의 중요성이 점점 강조되고 있다. 그런데 실제 이용가능한 지역 자료의 공간단위는 연구 분석을 위한 기능지역 단위와 일치하지 않는 경우가 종종 발생하며, 이로 인해 발생하는 문제를 해결하기 위해 이용가능한 지역 단위 자료를 연구 분석을 위한 공간 단위로 재구성하는 방법이 요구된다. 본 연구는 면적 가중치 내삽법, pycnophylactic 방법, dasymetric 방법, Area-to-point 내삽법 등을 검토하고 도시지역 자료의 효율적인 재구성 방법으로 면적 가중치 내삽법을 수정하여 인구 가중치 내삽법(population weighted interpolation)을 제안하였다. 인구 가중치 내삽법은 미국 뉴욕주 이리 카운티(Erie County)를 연구 사례로 면적 가중치 방법 pycnophylactic 방법을 RMS 에러, 자료 분포 유형, 공간 자기상관의 측면에서 비교되었다.

• 한국수자원학회논문집
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• 제47권4호
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• pp.357-370
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• 2014

본 연구에서는 격자기반의 공간분포 강우장에서 호우지속기간동안 지속시간별 면적최대강우량을 산정할 수 있는 탐색기법을 개발하여 DAD 분석을 실시하고 그 적용성을 평가하고자 한다. 우선, 세 가지 탐색기법(Box-tracking, Point-tracking, Advanced point-tracking)의 알고리즘을 구성하고, 가상의 강우장(1 hr 지속시간)을 대상으로 각 탐색기법의 성능을 검증하였다. 다음으로 용담댐 유역의 실제 강우사상을 선택하여 개발된 탐색기법과 GIS를 이용한 고전적인 방법을 사용하여 DAD 분석을 실시하고 그 결과를 비교 분석하였다. Box-tracking의 경우, Point-tracking과 Advanced point-tracking에 비하여 상대적으로 빠른 검색이 가능하지만, 강우장의 공간분포 형태를 고려하지 못하여 타 탐색기법에 비해 유역크기별 면적최대강우량이 과대 산정되었다. 반면, Point-tracking과 Advanced point-tracking은 강우장의 공간분포 형태를 적절하게 반영하여 면적최대강우량 산정이 가능하였으며, 특히 두개 이상의 호우중심이 존재할 경우 Advanced point-tracking은 Point-tracking보다 우수한 탐색성능을 보여주었다. 따라서 본 연구에서 제안하는 탐색기법은 DAD 분석 및 면적감소계수 계산을 위한 유용한 도구로 활용이 가능할 것으로 판단된다.

• 전기학회논문지
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• 제59권6호
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• pp.1034-1040
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• 2010

This paper presents a calculation method of the area of severity for the stochastic assessment of voltage sags. In general, the annual expected numbers of voltage sags at an individual load point can be estimated stochastically. However, in order to assess the system voltage sag performance considering many sensitive load points together, it is necessary to determine and analysis the area of severity for the load points. The area of severity to voltage sags is the network region where the fault occurrences will simultaneously lead to voltage sags at different load points. In this paper, the concept of the voltage sag assessment and the calculation method of the area of severity are addressed. The analysis of the area of severity is performed on the IEEE 30-bus test system by using the proposed method. The method is useful for the stochastic assesment of voltage sags and the establishment of systematic plans for voltage sag mitigation.

• 한국게임학회 논문지
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• 제11권2호
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• pp.161-166
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• 2011

본 논문에서는 동작인식 위한 정확한 배경 분할 및 특징점 추출 방법을 제안한다. 배경 분할 과정에서는 먼저, HSV 입력 이미지를 RGB 색상 공간에서 HSV 색상 공간으로 변환한 뒤, H와 S 값에 대한 두 개의 임계치를 사용하여 살색 영역을 분할, 프레임간의 차영상을 이용하여 움직임이 있는 영역을 추출한다. 차영상에서 발생하는 잔상 영역을 제거하기 위하여 헤시안 어파인 영역 검출기를 적용하고, 잡음이 제거된 차 영상과 살색 영역의 이진화 영상을 이용하여 사람의 동작이 나타나는 영역을 분할한다. 특징점 추출 과정은 전체 영상을 블록 단위로 나눠서 각 블록 안에서 분할된 영상에 포함되는 픽셀들의 중점을 구하여 특징점을 추출한다. 실험결과 복잡한 환경에서도 정확한 배경 분할과 사용자 동작을 대표하는 특징점 추출이 약 12 fps로 가능함을 알 수 있었다.

• 로봇학회논문지
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• 제18권1호
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• pp.1-9
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• 2023

This paper presents an optimal path planning strategy for aerial searching and surveying of a user-designated area using multiple Unmanned Aerial Vehicles (UAVs). The method is designed to deal with a single unseparated polygonal area, regardless of polygonal convexity. By defining the search area into a set of grids, the algorithm enables UAVs to completely search without leaving unsearched space. The presented strategy consists of two main algorithmic steps: cellular decomposition and path planning stages. The cellular decomposition method divides the area to designate a conflict-free subsearch-space to an individual UAV, while accounting the assigned flight velocity, take-off and landing positions. Then, the path planning strategy forms paths based on every point located in end of each grid row. The first waypoint is chosen as the closest point from the vehicle-starting position, and it recursively updates the nearest endpoint set to generate the shortest path. The path planning policy produces four path candidates by alternating the starting point (left or right edge), and the travel direction (vertical or horizontal). The optimal-selection policy is enforced to maximize the search efficiency, which is time dependent; the policy imposes the total path-length and turning number criteria per candidate. The results demonstrate that the proposed cellular decomposition method improves the search-time efficiency. In addition, the candidate selection enhances the algorithmic efficacy toward further mission time-duration reduction. The method shows robustness against both convex and non-convex shaped search area.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제27권1호
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• pp.75-86
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• 2023

The angle of attack is highly sensitive to pitch point in the airfoil shape and the decline of pitch point value induces smaller angle of attack, which implies that airfoil profile possessing closer pitch point to the airfoil tip reacts more sensitively to upcoming wind. The method of conformal transformation functions is employed for airfoil profiles and airfoil surfaces are expressed with a trigonometric series form. Attack angle and ideal lift coefficient distributions are investigated for various airfoil profiles in wind turbine blade regarding conformal transformation and pitch point. The conformed angle function representing the surface angle of airfoil shape generates various attack angle distributions depending on the choice of surface angle function. Moreover, ideal attack angle and ideal lift coefficient are susceptible to the choice of airfoil profiles and uniform loading area. High ideal attack angle signifies high pliability to upcoming wind, and high ideal lift coefficient involves high possibility to generate larger electric energy. According to results obtained pitch point, airfoil shape, uniform loading area, and the conformed airfoil surface angle function are crucial factors in the determination of angle of attack.