• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1939-1944
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• 2003

This paper presents a global path planning algorithm based on a visibility graph method, and applies additionally various constraints for constructing the reduced visibility graph. The modification algorithm for generating the rounded path is applied to the globally shortest path of the visibility graph using the robot size constraint in order to avoid the obstacle. In order to check the visibility in given 3D map data, 3D CAD data with VRML format is projected to the 2D plane of the mobile robot, and the projected map is converted into an image for easy map analysis. The image processing are applied to this grid map for extracting the obstacles and the free space. Generally, the tree size of visibility graph is proportional to the factorial of the number of the corner points. In order to reduce the tree size and search the shortest path efficiently, the various constraints are proposed. After short paths that crosses the corner points of obstacles lists up, the shortest path among these paths is selected and it is modified to the combination of the line path and the arc path for the mobile robot to avoid the obstacles and follow the rounded path in the environment. The proposed path planning algorithm is applied to the mobile robot LCAR-III.

• 한국조경학회지
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• 제25권2호
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• pp.31-42
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• 1997

Visibility has been used for Visual Impact Assessment and Buildingheight Control. The purpose of this study is to elaborate visibility analysis technique in GIS, and to design a visual information system baed on this technique for diverse application. The results of this study are as follows : 1) By classifying visibility analysis techniques into two groups, Each one's merits and demerits were investigated. Practically GIS visibility analysis by DTM model using contour map and investigating it by means of site-observation can be the most effective method. 2) A visibility analysis techniquwe for V.I.A. and B.H.C. was presented by studying GIS visibility analysis by means of DTM model using contour map. There were 5 problems. 3) Adequate analysis techniques were presented according to the landscape factor-road, ship-route, port, mountain, etc. 4) Viewing distance from road and ship-route in visual corridor, landma가 visibility and distance, the angle of incidence and invisible region's depth are helpful for land scape management or land use planning.

• 제어로봇시스템학회논문지
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• 제16권1호
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• pp.48-52
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• 2010

In this paper, we introduce a new path planning algorithm which combines the merits of a visibility graph algorithm and an adaptive cell decomposition. We quantize a given map with empty cells, blocked cells, and mixed cells, then find the optimal path on the quantized map using a visibility graph algorithm. For reducing the number of the quantized cells we use the quad-tree technique which is used in an adaptive cell decomposition, and for improving the performance of the visibility checking in making a visibility graph we propose a new visibility checking method which uses the property of the quad-tree instead of the well-known rotational sweep-line algorithm. For the more efficient visibility checking, we propose two additional improvements for our suggested method. Both of them are used for reducing the visited cells in the quad-tree. The experiments for a performance comparison of our algorithm with other well-known algorithms show that our proposed method is superior to others.

• 한국군사과학기술학회지
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• 제12권1호
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• pp.80-87
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• 2009

The purpose of this study is to analyze the MAUP's effect in visibility analysis using GIS. MAUP normally occurs in the process in terrain spatial analysis including visibility analysis. There are two different types of grid data(based on digital map and Digital Terrain Elevation Data) and 10 different types of areal units are made for modeling, such as $5m{\times}5m,\;10m{\times}10m,\;15m{\times}15m,\;20m{\times}20m,\;25m{\times}25m,\;30m{\times}30m,\;35m{\times}35m,\;40m{\times}40m,\;45m{\times}45m,\;50m{\times}50$. By analyzing the result, it was possible to observe varying viewshed areas according to different grid cell sizes and the viewshed area did not varied linearly as expected. From a general point of view, smaller unit data map out the real world in more detail, but the results of modeling do not always reach a good conclusion when data are used in modeling for terrain analysis because of the MAUP' effect. The grid cell sizes of 30m or less seems to be adequate for visibility analysis, including terrain analysis considering vegetation heights.

• 한국통신학회논문지
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• 제31권12C호
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• pp.1194-1200
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• 2006

본 논문에서는 국부 통계 특성을 이용한 적응 MAP 방식의 고해상도 영상 복원 알고리즘에 대해 제안한다. 고해상도 원 영상의 윤곽선을 보존하기 위해 저해상도 영상의 국부 특성을 이용하여 시각함수를 정의하였고, MAP(Maximum A Posteriori) 추정 방식을 이용하여 국부적인 열화 정도(smoothness)를 조절하였다. 또한 가중치가 부여된 함수를 이용하여 원 고해상도 영상에 가능한 가까운 최적의 해를 찾기 위하여 반복기법을 사용하였으며, 열화 요소는 매 반복 단계마다 부분적으로 복원된 고해상도 영상으로부터 이용하였다. 제안된 방식의 성능을 실험 결과를 통해 확인할 수 있었다.

• 한국멀티미디어학회논문지
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• 제11권5호
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• pp.692-702
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• 2008

게임이나 가상현실공간에서의 경로 계획은 자율적으로 움직이는 캐릭터들의 수가 많아짐에 따라 그 비중이 높아지고 있다. 로드맵 방식이란 이동 가능한 경로를 나타내는 지도를 사전에 제작하여 경로를 계획하는데 이용하는 방법을 말하며 높은 품질의 경로를 제공할 수 있다는 장점이 있다. 그렇지만 로드맵이 한번 정해지면 모든 캐릭터가 하나의 지도 위에서 움직이기 때문에 크기가 다른 캐릭터들의 특성이 반영되지 못하는 단점이 있다. 본 논문에서는 캐릭터별로 자신의 크기에 맞는 로드맵을 가지고 경로 계획에 각자 이용할 수 있는 효율적인 방법을 제안한다. 이 방법은 캐릭터의 수에 관계없이 전체 지도는 가시성 그래프를 응용하여 1회만 생성하고, 캐릭터의 크기에 따라 이동 가능한 경로를 점진적으로 추가하는 방식으로 제안되기 때문에 효율적이다. 시뮬레이션을 통해 개별 로드맵 방식으로 얻을 수 있는 효과를 보여주며 이때 수반되는 트레이드오프를 분석한다.

• 한국시뮬레이션학회논문지
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• 제15권2호
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• pp.31-39
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• 2006

가시성그래프는 최소 탐색 공간으로 게임환경을 모델링하여 효과적으로 길을 찾을 수 있도록 하는 방법으로 잘 알려져 있다. 일반화 가시성그래프는 가시성그래프의 가장 큰 단점으로 지적되는 "벽-껴안기" 문제를 해결하기 위해 확장된 장애물의 경계 위에 생성된 가시성그래프이다. 일반화 가시성그래프에 의해 구해진 경로는 근사 최적이며 자연스럽게 보이는 장점이 있다. 본 논문에서는 변화하는 출발점과 목표점과 정적인 장애물 사이를 움직이는 게임 캐릭터에 효과적으로 일반화 가시성그래프를 적용하는 방법을 제안한다. 일반화 가시성그래프는 일단 생성되면 최소 탐색공간을 보장하지만 그 생성 자체는 노드사이의 링크의 교차 여부론 일일이 체크하여야 하므로 시간이 많이 소요된다. 아이디어는 먼저 정적인 장애물만으로 지도를 생성해 놓고 출발점과 목표점을 빠르게 포함시키는 것이다. 출발점과 목표점의 포함 부분이 여러 번 반복되어야 하는 과정이므로 출발점과 목표점을 빠르게 포함시키는데에 연산 기하학 분야의 회전 plane-sweep 알고리즘을 이용할 것을 제안한다. 시뮬레이션 결과는 전체 그래프를 매번 생성하는 것보다 제안한 방법의 실행시간이 39%-68% 정도 향상되었음을 보여준다.

• Journal of information and communication convergence engineering
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• 제22권1호
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• pp.70-79
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• 2024

Bad weather conditions such as haze lead to a significant lack of visibility in images, which can affect the functioning and reliability of image processing systems. Accordingly, various single-image dehazing (SID) methods have recently been proposed. Existing SID methods have introduced effective visibility improvement algorithms, but they do not reflect the image's perspective, and thus have limitations that distort the sky area and nearby objects. This study proposes a new SID method that reflects the sense of space by defining the correlation between image brightness and haze. The proposed method defines the haze intensity by calculating the airlight brightness deviation and sets the weight factor of the depth map by classifying images based on the defined haze intensity into images with a large sense of space, images with high intensity, and general images. Consequently, it emphasizes the contrast of nearby images where haze is present and naturally smooths the sky region to preserve the image's perspective.

• 한국항공우주학회지
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• 제35권12호
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• pp.1095-1100
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• 2007

도심지에서는 지형지물 및 건물 등에 의한 영향으로 가시위성 확보가 어려워지게 되며, 이는 사용자 위치결정 및 정확도에 영향을 미친다. 본 논문에서는 3D GIS 수치지도를 이용하여 서울 도심의 특정 지역을 3D 모델로 생성하는 기법에 대해 기술하고, 직선-폴리곤 충돌검사 알고리즘을 적용한 도심지에서의 가시위성 분석 기법 개발 및 필드 실험을 통한 검증을 수행하였다. 도심의 3D 모델을 이용하여 GPS/갈릴레오 단독 수신과 동시 수신의 경우에 대한 가시성을 DOP (Dilution of Precision)관점에서 분석하였다

• IEIE Transactions on Smart Processing and Computing
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• 제3권2호
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• pp.65-73
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• 2014

An overall responding security-centered framework is necessary required for infringement accidents, failures, and cyber threats. On the other hand, the correspondence structures of existing administrative, technical, physical security have weakness in a system responding to complex attacks because each step is performed independently. This study will recognize all internal and external users as a potentially threatening element. To perform connectivity analysis regarding an action, an intelligent convergence security framework and road map is suggested. A suggested convergence security framework was constructed to be independent of an automatic framework, such as the conventional single solution for the priority defense system of APT of the latest attack type, which makes continuous reputational attacks to achieve its goals. This study suggested the next generation convergence security framework to have preemptive responses, possibly against an APT attack, consisting of the following five hierarchical layers: domain security, domain connection, action visibility, action control, and convergence correspondence. In the domain, the connection layer suggests a security instruction and direction in the domains of administrative, physical and technical security. The domain security layer has consistency of status information among the security domain. A visibility layer of an intelligent attack action consists of data gathering, comparison and decision cycle. The action control layer is a layer that controls the visibility action. Finally, the convergence corresponding layer suggests a corresponding system of before and after an APT attack. The administrative security domain had a security design based on organization, rule, process, and paper information. The physical security domain is designed to separate into a control layer and facility according to the threats of the control impossible and control possible. Each domain action executes visible and control steps, and is designed to have flexibility regarding security environmental changes. In this study, the framework to address an APT attack and load map will be used as an infrastructure corresponding to the next generation security.