• Korean Institute of Interior Design Journal
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• v.18 no.4
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• pp.97-104
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• 2009

This thesis analyzed arrangement and mixture method of function elements, which are getting more important in museum planning. It used quantitative method, Space Syntax and Visibility Graph Analysis tool to analyze five case museums. Through this analysis, advantages and disadvantages of two methods were derived and case museums' arrangement and mixture attributes were grasped. Results of the analysis were derived differently by two kinds of plan form which were room to room type and open type. Open typed museum recorded similar graphs of Integration, Visual Integration and Visual Connectivity. Since whole space structures were relatively simple and structure of exhibition halls were opened, the results of Space Syntax and Visibility Graph Analysis had similar graphs. Room to room typed museum showed differences in Integration, Visual Integration and Visual Connectivity. In the result, the most accessible space was lobby and Mediation Space became the center of visibility. Also, the exhibition hall, where the opening of room to room typed exhibition hall was penetrated visually, became a center of visibility. Lobby space, which was close to entrance, had the highest Visibility Connectivity. As Space Syntax could analyze the museum as whole space structure, Space Syntax showed strength in room to room typed museum analysis compared to open typed museum analysis which has relatively simple structure. Visibility Graph Analysis could expect the flow of exhibit distance including visibility analysis unlike the flow of exhibit distance with space arrangement. The exhibition hall, which secures the sight to penetration of an opening, couldn't be analyzed in existing Space Syntax. However, it became the biggest advantages in Visibility Graph Analysis of room to room typed museum. Visibility Graph Analysis derived detailed results in exhibit arrangement so it will be the useful method not only for architecture but also for planning of exhibit arrangement in open typed museum. Through this study, various possibilities on Quantitative Analysis Method of Museum Architecture could be verified. However, the analysis still has limitation of second dimension. Therefore, diverse and liberal following study will be expected to accomplish.

• Journal of the military operations research society of Korea
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• v.16 no.2
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• pp.56-74
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• 1990

Programming-in-the-Large refers to software development environment and includes the organization and representation of a system structure, module decomposition, component dependence analysis, seperate compilation, subsystem and composition identification. The most intricate problem in this environment is the mastery of the structural complexity of large software systems. Ada programming language is tailored to the needs for building of large, integrated software systems from many program units. The visibility graph generating model presented in this paper transforms Ada source program into a visibility graph with nodes for program units and edges for visibility relations among program units. The system description in terms of program units and their visibility relations produced by this model can be utilized for some apects of Programming-in-the-Large environment and also assists designeers, programmers, integrators and maintainers in defining, understanding and exploring the structure of evolving software systems. The model designed and implemented in Ada programming language runs on PCs and will remain useful both in practice and as experimental tool.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.1
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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.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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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.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.12
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• pp.874-880
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• 2019

This paper introduces a method which can be effectively used for the path planning of UAV in a realistic map which has mountainous terrains, air defense networks and radars based on the Visibility Graph. Existing studies of Visibility Graph have been studied mainly for simple shape obstacles in 2-dimensional environment such as self-driving cars which avoid buildings. However, for UAV, Visibility Graph must be used in 3-dimensional environment for the variance of altitude. This occurs significant elapsed time increase because of the increase of the amount of the visibility of node sets. To solve this problem, this paper decrease the number of nodes which consists the complex terrain environments using convex hull based on Layered Visibility Graph. With convex hull method, this paper confirmed that the elapsed time is decreased about 99.5% compared to the case which has no decrease of the number of nodes.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.418-418
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• 2000

This paper proposes a path planning algorithm for mobile robot. To generate an optimal path and minimum time path for a mobile robot, we use the Genetic Algorithm(GA) and Visibility Graph. After finding a minimum-distance between start and goal point, the path is revised to find the minimum time path by path-smoothing algorithm. Simulation results show that the proposed algorithms are more effective.

• Journal of the Korea Society for Simulation
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• v.15 no.2
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• pp.31-39
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• 2006

The visibility graph is a well-known method for efficient path-finding with the minimum search space modelling the game world. The generalized visibility graph is constructed on the expanded obstacle boundaries to eliminate the "wall-hugging" problem which is a major disadvantage of using the visibility graph. The paths generated by the generalized visibility graph are guaranteed to be near optimal and natural-looking. In this paper we propose the method to apply the generalized visibility graph efficiently for game characters who moves among static obstacles between varying start and goal points. Even though the space is minimal once the generalized visibility graph is constructed, the construction itself is time-consuming in checking the intersection between every two links connecting nodes. The idea is that we build the map for static obstacles first and then incorporate start and goal nodes quickly. The incorporation of start and goal nodes is the part that must be executed repeatedly. Therefore we propose to use the rotational plane-sweep algorithm in the computational geometry for incorporating start and goal nodes efficiently. The simulation result shows that the execution time has been improved by 39%-68% according to running times in the game environment with multiple static obstacles.

• Korean Institute of Interior Design Journal
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• v.23 no.2
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• pp.166-173
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• 2014

This study analyzed visual-perceptual centrality as a measure to solve the confusion that might occur in visitor's movement in analyzing contemporary museums that have recently expand. Also, this study proposed a new methodology to understand the relationships of the occurrence and convergence of visual-perceptual power. The existing visibility graph analysis mostly ends up in identifying nodes corresponding to the physical environment of museums while the newly proposed visibility graph analysis is a methodology that can analyze the landmark on which the visual-perceptual power occurs and converges, by setting visible space elements as analysis variables, which showed a possibility to draw more reliable results in parallel to the existing analysis, and the results of this analysis are as follows. A public museum located in downtown has a limitation that it cannot but be multi-layered as a way to enlarge for the accommodation of a variety of programs on a limited site. Also, this study found that the problem of visitor orientation occurring in the multi-layer process was solved by a major space which was visual-perceptually void. Also, its types can be summarized into two types: One is setting parameter spaces (ramps, staircases, hallways) linked visual-perceptually to the major space and the other is solving the confusion of the visitor's movement by composing a simple exhibition space. In particular, it is judged that the type solving the confusion of the visitor's movement by composing a simple exhibition space also had a relationship with changes in the characteristics of the exhibited works by period. In addition, it was found that the entrance also appeared in two types: dependent type and independent type in the major space according to the characteristics of the major space.

• International Journal of Aeronautical and Space Sciences
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• v.8 no.2
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• pp.107-120
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• 2007

Coordination of multiple UAVs is an essential technology for various applications in robotics, automation, and artificial intelligence. In general, it includes 1) waypoints assignment and 2) trajectory generation. In this paper, we propose a new method for this problem. First, we modify the concept of the standard visibility graph to greatly improve the optimality of the generated trajectories and reduce the computational complexity. Second, we propose an efficient stochastic approach using simulated annealing that assigns waypoints to each UAV from the constructed visibility graph. Third, we describe a method to detect collision between two UAVs. FinallY, we suggest an efficient method of controlling the velocity of UAVs using A* algorithm in order to avoid inter-UAV collision. We present simulation results from various environments that verify the effectiveness of our approach.

• International Journal of High-Rise Buildings
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• v.12 no.1
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• pp.83-91
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• 2023

Under the dual pressure of population growth and land shortage, threedimensional development is the inevitable choice for cities in China. In such a scenario, a mixed-use complex has considerable potential in its realization and research. Based on space syntax and the three-dimensional visibility graph analysis, this paper describes the spatial and functional layout of the Shanghai Super Brand Mall and studies the relationship between spatial visibility and user behaviour through linear regression analysis and correlation analysis. This paper studies three different types of user behaviour, namely, path selection, staying selection, and store selection, and finds that spatial visibility and accessibility have different effects on user behaviour depending on the type and purpose of the activity. This paper reveals the influence of spatial and functional layout on user behaviour and puts forward the corresponding design strategy under the three-dimensional environment.