• Proceedings of the KIEE Conference
• /
• 2004.11c
• /
• pp.520-522
• /
• 2004

In this paper, we propose the algorithm of path planning and obstacle avoidance for mobile robot. We call the proposed method Random Access Sequence(RAS) method. In the proposed method, a small region is set first and numbers are assigned to its neighbors, then the path is selected using these numbers. It has an advantage of fast planning and simple operation. This means that new path selection may be possible within short time and that helps a robot to avoid obstacle in any direction. When a robot meets moving obstacles, it avoids obstacles in a random direction. Sonar ranger is useful to get obstacle information and RAS may be a good solution for path planning.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.23 no.4
• /
• pp.11-20
• /
• 1998

This paper deals with a mathematical model and an algorithm for the problem of determining k most vital arcs in the shortest path problem. First, we propose a 0-1 integer programming model for finding k most vital arcs in shortest path problem given the ordered set of paths with cardinality q. Next, we also propose an algorithm for finding k most vital arcs ln the shortest path problem which uses the 0-1 Integer programming model and shortest path algorithm and maximum flow algorithms repeatedly Malik et al. proposed a non-polynomial algorithm to solve the problem, but their algorithm was contradicted by Bar-Noy et al. with a counter example to the algorithm in 1995. But using our algorithm. the exact solution can be found differently from the algorithm of Malik et al.

• Management Science and Financial Engineering
• /
• v.11 no.2
• /
• pp.85-103
• /
• 2005

In this paper, we consider the routing and wavelength assignment problem in survivable WDM transport network without wavelength conversion. We assume the single-link failure and a path protection scheme in optical layer. When a physical network and a set of working paths are given, the problem is to select a link-disjoint protection path for each working path and assign a wavelength for each working and protection path. We give an integer programming formulation of the problem and propose an algorithm to solve it. Though the formulation has exponentially many variables, we solve the linear programming relaxation of it by using column generation technique. We devise a branch-and price algorithm to solve the column generation problem. After solving the linear programming relaxation, we apply a variable fixing procedure combined with the column generation to get an integral solution. We test the proposed algorithm on some randomly generated data and test results show that the algorithm gives very good solutions.

• Journal of Korea Multimedia Society
• /
• v.21 no.4
• /
• pp.535-544
• /
• 2018

Developing a new texture path tool is crucial in 3D industries to automatically manage and set up texture paths for characters and environment modelings. For a better study, I compare the problems, methods and functions of the new tool(SongRepath tool) with other commonly used tools such as File Path Editor, Genie, He Texture Path. Next, I analyze the top down method system for these commonly used tools, and create a new bottom-up algorithm for a better use and efficiency. Finally, analyzing and comparing SongRepath tool with other tools in terms of operation in convenience, steps for results, checking number of Texture files, checking the numbers of new paths, checking the numbers of files not found, checking the numbers of path not changed, errors or problems, and availability of cancelation while proceeding the result. As a result, this study shows that SongRepath tool has less errors and saves more time on the processing works.

• Journal of the Korea Society for Simulation
• /
• v.12 no.1
• /
• pp.11-19
• /
• 2003

Dubins showed that any shortest path of a car-like robot consists of exactly three path segment which are either arcs of circles of radius r(denoted C), or straight line segments(denoted S). Possible six types classified into two families, i.e. CSC and CCC. CSC includes 2 types(LRL and RLR) and CSC includes 4 types(LSL, RSR, LSR, RSL). This paper proposes new formulae for CSC family to find the shortest smooth path between the initial and final configurations of a car-like robot. The formulae is used for finding connection points explicitly between C\longrightarrowS and S\longrightarrowC which are necessary for real applications. The formulae have simple forms mainly because they are transformed into origin of their original coordinates of initial and target configuration, and derived from a standard forms which are a representative configuration of LSL and LSR type respectively. The proposed formulae, which are derived from the standard forms, are simple and new method.

• Journal of Computational Design and Engineering
• /
• v.3 no.2
• /
• pp.132-139
• /
• 2016

In this paper, a minimum time path planning strategy is proposed for multi points manufacturing problems in drilling/spot welding tasks. By optimizing the travelling schedule of the set points and the detailed transfer path between points, the minimum time manufacturing task is realized under fully utilizing the dynamic performance of robotic manipulator. According to the start-stop movement in drilling/spot welding task, the path planning problem can be converted into a traveling salesman problem (TSP) and a series of point to point minimum time transfer path planning problems. Cubic Hermite interpolation polynomial is used to parameterize the transfer path and then the path parameters are optimized to obtain minimum point to point transfer time. A new TSP with minimum time index is constructed by using point-point transfer time as the TSP parameter. The classical genetic algorithm (GA) is applied to obtain the optimal travelling schedule. Several minimum time drilling tasks of a 3-DOF robotic manipulator are used as examples to demonstrate the effectiveness of the proposed approach.

• Journal of Biomedical Engineering Research
• /
• v.24 no.2
• /
• pp.77-82
• /
• 2003

Virtual colonoscopy is a non-invasive computerized procedure to detect polyps by examining the colon from a CT data set. To fly through the inside of colons. the extraction of a suitable flight-path is necessary to Provide the viewpoint and view direction of a virtual camera. However. manual path extraction by Picking Points is a very time-consuming and difficult task due 1,c, the long and complex shape of colon. Also, existing automatic methods are computationally complex. and tend to generate an improper and/or discontinuous path for complicated regions. In this paper, we propose a fast flight-path generation algorithm using the distance and order maps. The order map Provides all Possible directions of a path. The distance map assigns the Euclidean distance value from each inside voxel to the nearest background voxel. By jointly using these two maps. we can obtain a proper centerline regardless of thickness and curvature of an object. Also, we Propose a simple smoothing technique that guarantees not to collide with the surface of an object. The phantom and real colon data are used for experiments. Experimental results show that for a set of human colon data, the proposed algorithm can provide a smoothened and connected flight-path within a minute on an 800MHz PC. And it is proved that the obtained flight-Path provides successive volume-rendered images satisfactory for virtual navigation.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2000.10a
• /
• pp.113-116
• /
• 2000

The purpose of this study is to present a method for determining the k most vital arcs in shortest path problem using an evolutionary algorithm. The problem of finding the k most vital arcs in shortest path problem is to find a set of k arcs whose simultaneous removal from the network causes the greatest increase in the total length of shortest path. The problem determining the k most vital arcs in shortest path problem has known as NP-hard. Therefore, in order to deal with the problem of real world the heuristic algorithm is needed. In this study we propose to the method of finding the k-MVA in shortest path problem using an evolutionary algorithm which known as the most efficient algorithm among heuristics. For this, the expression method of individuals compatible with the characteristics of shortest path problem, the parameter values of constitution gene, size of the initial population, crossover rate and mutation rate etc. are specified and then the effective genetic algorithm will be proposed. The method presented in this study is developed using the library of the evolutionary algorithm framework (EAF) and then the performance of algorithm is analyzed through the computer experiment.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.18 no.11
• /
• pp.1048-1055
• /
• 2005

The formula to calculate a variation of optical path length of single crystal by the electric field was derived by this study. The formula was applied to $Bi_{12}SiO_{20}$ single crystal. The results are as follows. In case of the applied electric field in the body diagonal direction and the passing light along the same direction, the variation of optical path length had the largest value. The symmetry of the space distribution of optical path length satisfied $E3C_2\;8C_3$, the set of elements of the symmetry of $Bi_{12}SiO_{20}$ single crystal. The property which gave the largest influence to the variation of optical path length is the strain of length by the Inverse piezoelectric effect. The second influence, is the variation of the refractive index by the electro-optic effect. The variation of optical path length by the inverse piezoelectric effect and by the electro-optic effect have a reverse sign each other.

• Journal of Korea Multimedia Society
• /
• v.16 no.7
• /
• pp.897-904
• /
• 2013

The recursive circulant network G(N,d) can be widely used in the design and implementation of parallel processing architectures. It consists of N identical nodes, each node is connected through bidirectional, point-to-point communication channels to different neighbors by jumping $d^i$, where $0{\leq}i{\leq}{\lceil}{\log}_dN{\rceil}$ - 1. In this paper, we investigate the routing of a message on $G(2^m,4)$, a special kind of RCN, that is key to the performance of this network. On $G(2^m,4)$ we would like to transmit k packets from a source node to k destination nodes simultaneously along paths on this network, the $i^{th}$ packet will be transmitted along the $i^{th}$ path, where $1{\leq}k{\leq}m-1$, $0{{\leq}}i{{\leq}}m-1$. In order for all packets to arrive at a destination node quickly and securely, we present an $O(m^4)$ routing algorithm on $G(2^m,4)$ for generating a set of one-to-many node-disjoint and nearly shortest paths, where each path is either shortest or nearly shortest and the total length of these paths is nearly minimum since the path is mainly determined by employing the Hungarian method.