• 한국통신학회논문지
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• 제34권11A호
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• pp.862-869
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• 2009

본 논문에서는 순간적인 채널 상태에 따라 K, 즉 survivor path의 개수를 적응적으로 조절하는 MIMO(Multiple Input Multiple Output) 검출 기법을 제안한다. 최적의 성능을 가지지만 높은 복잡도의 단점을 가지는 MLD(Maximum Likelihood Detection)의 단점을 개선하기 위해 MLD에 근접한 성능을 가지면서 복잡도는 확연히 감소시킨, 적응형 K-best SD (Sphere Decoding) 기법들이 제안되었지만, 채널 상태를 판별하기 위한 지표로, 채널의 페이딩 이득만을 이용할 뿐 순시적인 SNR(Signa1 to Noise Ratio) 값은 반영하지 못하는 단점을 가진다. 제안된 기법은 이러한 단점을 보완하기 위해 K를 조절하기 위한 채널 지표로 채널의 페이딩 성분뿐 아니라 SNR 성분까지 반영하는 path metric 값의 특성을 이용하여, 기존의 기법과 동일한 성능을 가지면서 낮은 복잡도를 가진다.

• 한국실내디자인학회논문집
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• 제15권3호
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• pp.155-162
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• 2006

Space is integrated or segment with organic formation by circulation path. It estimates important problem to grasp as factor that promote movement of visitor and space organization without grasping circulation as connection relation about simple space function from these viewpoint, is a thing which this study does not cause confusion to visitor's circulation path through data that analyze form of space connection and visitor's circulation path as quantitative in museum space and layout form that access by easy each unit exhibition grasps what it is. This study does factor grasping for guideline and inspection circulation path of layout by purpose in exhibition space on the basis of analytical result that grasps connection form between exhibition area that grasp laying stress on visitor's movement and appears in space through follow-up survey for circulation path of museum exhibition area. Space connection form that is expose by sequence of investigation and analysis(II) estimates on constituent affecting to visitor's circulation, and these do not speak for all space connection forms at the museum, but may systematize typology about connection form of unit spaces to utilize by indicator pointer of space planning if continue study to various spatial sphere more than hereafter. Unit exhibition area, divide connection form of space by grid and tree and laying stress on this quantitative data by spectator follow-up survey comparison and Estimate that space connection form provides partial basis of judgement for supposition that can promote direction and circulation path about visitor's movement if summarize result of investigation and analysis (III).

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
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• pp.283-286
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• 1996

This study suggests a new methodology for the fault diagnosis based on the signed digraph in developing the fault diagnosis system of a boiler plant. The suggested methodology uses the new model, fault-effect tree. The SDG has the advantage, which is simple and graphical to represent the causal relationship between process variables, and therefore is easy to understand. However, it cannot handle the broken path cases arisen from data uncertainty as it assumes consistent path. The FET is based on the SDG to utilize the advantages of the SDG, and also covers the above problem. The proposed FET model is constructed by clustering of measured variables, decomposing knowledge base and searching the fault propagation path from the possible faults. The search is performed automatically. The fault diagnosis system for a boiler plant, ENDS was constructed using the expert system shell G2 and the advantages of the presented method were confirmed through case studies.

• Journal of information and communication convergence engineering
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• 제14권1호
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• pp.14-20
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• 2016

The AODV protocol uses many RREQ messages and one RREP message in the path-discovery process. This protocol has only one metric, the number of hops. Although it is simple, this protocol is not efficient. To avoid this problem, we propose a new AODV with two auxiliary metrics (AuM-2-AODV). The AuM-2-AODV protocol tries multiple route replies, which reduces the chance of path failure and helps the network obtain a better data rate. It has two auxiliary metrics, the remaining energy of its nodes and the number of HELLO messages received at the nodes. With these two metrics, the reliable path from the source node to the destination node will be chosen. In this paper, the performance of the AuM-2-AODV is evaluated using the NS-3 simulator. The performance results show that AuM-2-AODV provides greater throughput and packet delivery ratio by 20% and up to 50% and about 100% in some cases, respectively, than previous protocols.

• 한국컴퓨터정보학회논문지
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• 제9권3호
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• pp.71-77
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• 2004

게임을 하다보면 유닛들이 목표를 찾아 가야하는데 알고리즘에 따라 시간과 거리가 많이 차이 나게 된다. 본 논문에서는 깊이 우선 탐색과 너비 우선 탐색 그리고 거리 값을 주어 개선된 알고리즘과 A* 알고리즘의 각각을 비교하며 특징들을 기술하고 알고리즘을 논하였다. 또한 A* 알고리즘에서 실제로 추정값을 구하여 가장 개선된 값을 찾는다. 마지막으로 A* 알고리즘과 다른 알고리즘의 비교를 통하여 A* 알고리즘을 우수성을 입증하고 A* 알고리즘을 이용한 간단한 길찾기를 제안하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 추계종합학술대회 논문집
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• pp.421-424
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• 1998

본 논문에서는 지역최소점에 도달하는 문제가 발생하지 않으며 빠르고 간편한 방식으로 로보트의 장애물 회피를 할 수 있는 윈도우 분석법을 이용한 새로운 장애물 회피와 경로계획 알고리듬 알고리듬을 제안한다. 미지의 경로상에서 장애물 윈도우에서의 특징을 이용하여 안전한 주행 경로를 선택하며, 장애물 회피를 한다. 시뮬레이션의 결과를 통하여 이 방법의 신회성과 우수성을 입증한다.

• 대한기계학회논문집A
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• 제25권12호
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• pp.2009-2018
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• 2001

This paper presents a region offsetting algorithm for tool-path generation. The proposed region offsetting algorithm is developed by expanding the 'PWID offset algorithm [Choi and Park, 1999]'designed to offset a simple polygon. The PWID offset algorithm has three important steps; 1) remove 'local invalid ranges'by invoking a PWID test, 2) construct a raw offset owe and 3) remove 'global invalid ranges'by finding self-intersections of the raw offset cure. To develop a region offsetting algorithm, we modified the PWID offset algorithm by expanding the concept of the 'global invalid range'in the third step. The time complexity of the proposed algorithm is approximately Ο(n), where n is the number of points, and it is free of numerical errors for practical purposes. The proposed algorithm has been implemented and tested with various real regions obtained by intersecting a sculptured surface with a plane.

• International Journal of Naval Architecture and Ocean Engineering
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• 제2권3호
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• pp.119-126
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• 2010

The response of ship roll oscillation under random ice impulsive loads modeled by Poisson arrival process is very important in studying the safety of ships navigation in cold regions. Under both external and parametric random excitations the evolution of the probability density function of roll motion is evaluated using the path integral (PI) approach. The PI method relies on the Chapman-Kolmogorov equation, which governs the response transition probability density functions at two close intervals of time. Once the response probability density function at an early close time is specified, its value at later close time can be evaluated. The PI method is first demonstrated via simple dynamical models and then applied for ship roll dynamics under random impulsive white noise excitation.

• International Journal of Ocean System Engineering
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• 제2권3호
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• pp.139-150
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• 2012

This paper presents an improved guidance algorithm for autonomous underwater vehicles (AUV) in 3D space for generating smoother vehicle turn during the course change at the way-points. The way-point guidance by the line-of-sight (LOS) method has been modified for correcting the reference angles to achieve minimal calculation and smoother transition at the way-points. The algorithm has two phases in which the first phase brings the vehicle to converge to a distance threshold point on the line segment connecting the first two way-points and the next phase generates an angular path with smoother transition at the way-points. Then the desired angles are calculated from the reference and correction angles. The path points are regularly parameterized in the spherical coordinates and mapped to the Cartesian coordinates. The proposed algorithm is found to be simple and can be used for real time implementation. The details of the algorithm and simulation results are presented.

• 한국멀티미디어학회논문지
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• 제12권6호
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• pp.824-832
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• 2009

Multi-radio multi-channel Wireless Mesh Network requires an effective management policy to control the assignment of channels to each radio. We concentrated our investigation on modeling method and solution to find a dynamic channel assignment scheme that is adapted to change of network traffic. Multi-path routing scheme was chosen to overwhelm the unreliability of wireless link. For a particular traffic state, our optimization model found a specific traffic distribution over multi-path and a channel assignment scheme that maximizes the overall network throughput. We developed a simple heuristic method for channel assignment by gradually removing clique load to obtain higher throughput. We also presented numerical examples and discussion of our models in comparison with existing research.