• Journal of Information Technology Services
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• v.9 no.3
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• pp.123-144
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• 2010

As knowledge becomes a critical success factor of companies nowadays, lots of rule-based systems have been and are being developed to support their activities. Large number of rule-based systems serve as Web sites to advise, or recommend their customers. They usually use a backward chaining inference algorithm based on backtrack to implement those interactive Web-enabled rule-based systems. However, when the users like customers are using these systems interactively, it happens frequently where the users do not know some of the answers for the questions from the rule-based systems. We are going to design a backward chaining inference methodology considering unknown facts based on backtrack technique. Firstly, we review exact and inexact reasoning. After that, we develop a backward chaining inference algorithm for exact reasoning based on backtrack, and then, extend the algorithm so that it can consider unknown facts and reduce its search space. The algorithm speeded-up inference and decreased interaction time with users by eliminating unnecessary questions and answers. We expect that the Web-enabled rule-based systems implemented by our methodology would improve users' satisfaction and make companies' competitiveness.

• Journal of Information Processing Systems
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• v.8 no.4
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• pp.685-692
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• 2012

B frame bi-directional predictions and the DIRECT mode coding of the H.264 video compression standard necessitate a complex mode decision process, resulting in a long computation time. To make H.264 feasible, this paper proposes an image backtrack-based fast (IBFD) algorithm and evaluates the performances of two promising fast algorithms (i.e., AFDM and IBFD). Evaluation results show that an image backtrack-based fast (IBFD) algorithm can determine DIRECT mode macroblocks with 13% higher accuracy, as compared with the AFDM. Furthermore, IBFD is shown to reduce the motion estimation time of B frames by up to 23% with a negligible quality degradation.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.6
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• pp.27-36
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• 1995

This paper covers algorithms to determine a machine assignment strategy to locations on a single straight track by minimizing the total backtrack distance. Three different algorithms ar presented: an efficient heuristic procedure, the branch-and-bound algorithm, and the nerual network approach. Simulation results show that the proposed algorithms have potential power to design an on-line optimizer.

• The Transactions of the Korea Information Processing Society
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• v.4 no.2
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• pp.606-615
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• 1997

This paper proposes an dffcient method for test pattern generation.Current test pattern genration systems generate a test vester for fault $F_{i+l}$ independently of the computation previously done for faults F1,F2...,Fi The proposed algorithm generates a test vector for fault $F_{i+l}$ by inheriting the test vector for fault Fi. A new test vector is grnerated from inherited values by gradually changing the inhderited values .The inherited values may partially activate a fauog and propagate the fault signal,Normally,this reduses the number of decision steps and backtracks in the second search.Experimental results for well-Known benchmark circuts show that the proposed algorithm is very efficient with small backtrack kimit;in combination eith other algorithms,it is very efficient for arbitrary backtrack limits.

• Journal of the Korea Society of Computer and Information
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• v.13 no.5
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• pp.219-227
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• 2008

As found in research on constraint satisfaction problems, the choice of variable ordering heuristics is crucial for effective solving of constraint optimization problems. For the special problems such as energy-efficient clustering in heterogeneous wireless sensor networks, in which cluster heads have an inclination to be near a base station, we propose a new approach based on the static preferences variable orderings and provide a pnode heuristic algorithm for a specific application. The pnode algorithm selects the next variable with the highest Preference. In our problem, the preference becomes higher when the cluster heads are closer to the optimal region, which can be obtained a Priori due to the characteristic of the problem. Since cluster heads are the most dominant sources of Power consumption in the cluster-based sensor networks, we seek to minimize energy consumption by minimizing the maximum energy dissipation at each cluster heads as well as sensor nodes. Simulation results indicate that the proposed approach is more efficient than other methods for solving constraint optimization problems with static preferences.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1996.10a
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• pp.106-110
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• 1996

고밀도 집적회로(VLSI)의 설계 과정에 있어 테스트(test)는 매우 중요한 과정으로서, 회로내의 결함(fault)을 찾기 위해 일련의 입력값을 넣어 그 출력값으로 고장 여부를 판단한다. 회로의 테스트를 위하여 사용되는 일련의 입력값을 테스트패턴(test pattern)이라 하며 최고 2n개의 테스트패턴이 생성될 수 있다. 그러므로 얼마나 작은 테스트패턴을 사용하여 회로의 결함 여부를 판단하느냐가 주된 관점이 된다. 기존의 테스트 패턴 생성 알고리즘인 휴리스틱(heuristic)조건에서 가장 큰 문제점은 빈번히 발생하는 백트랙(backtrack)과 이로 인한 시간과 기억장소의 낭비이다. 본 논문에서는 이러한 문제점을 보완하기 위해 퍼지 기법을 이용한 새로운 알고리즘을 제안한다. 제안된 기법에서는 고장신호 전파과정에서 여러개의 전파경로가 존재할 때, 가장 효율적인 경로를 선택하는 단계에서 퍼지 관계곱(Fuzzy Relational Product)을 이용한다. 이 퍼지 기법은 백트랙 수를 줄이고 기억장소와 시간의 낭비를 줄여 테스트 패턴 생성의 효율을 증가시킨다.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07b
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• pp.595-597
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• 2005

본 논문에서는 자율 에이전트에 의해 미지의 공간을 탐사하는 실시간 그래프 탐색 알고리즘 DFS-RTA*와 DFS-PHA*를 제안하고 그 효율성을 비교한다. 두 알고리즘들은 모두 깊이-우선 탐색(DFS)을 기초로 하고 있으며, 직전 노드로의 빠른 후진(backtrack) 을 위해 각각 실시간 최단 경로 탐색 방법인 RTA*와 PHA*를 적용하는 것이 특징이다. 본 논문에서는 대표적인 3차원 온라인 게임 환경인 Unreal Tournament 게임과 지능형 캐릭터 에이전트인 KGBot를 이용한 실험을 통해 두 탐색 알고리즘의 완전성과 효율성을 분석해본다.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2005.05a
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• pp.222-231
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• 2005

본 논문에서는 자율 에이전트에 의해 미지의 공간을 탐사하는 실시간 그래프 탐색 알고리즘 $DFS-RTA^{\ast}$와 $DFS-PHA^{\ast}$를 제안하고 그 효율성을 비교한다. 두 알고리즘들은 모두 깊이-우선 탐색(DFS)을 기초로 하고 있으며, 직전 노드로의 빠른 후진(backtrack) 을 위해 각각 실시간 최단 경로 탐색 방법인 $RTA^{\ast}$와 $PHA^{\ast}$를 적용하는 것이 특징이다. 본 논문에서는 대표적인 3차원 온라인 게임 환경인 Unreal Tournament 게임과 지능형 캐릭터 에이전트인 KGBot를 이용한 실험을 통해 두 탐색 알고리즘의 완전성과 효율성을 분석해본다.

• International Journal of Computer Science & Network Security
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• v.22 no.3
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• pp.285-291
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• 2022

WSN is the major component for information transfer in IoT environments. Source Location Privacy (SLP) has attracted attention in WSN environments. Effective SLP can avoid adversaries to backtrack and capture source nodes. This work presents a Two-Level Randomized Sector-based Routing (TLRSR) model to ensure SLP in wireless environments. Sector creation is the initial process, where the nodes in the network are grouped into defined sectors. The first level routing process identifies sector-based route to the destination node, which is performed by Ant Colony Optimization (ACO). The second level performs route extraction, which identifies the actual nodes for transmission. The route extraction is randomized and is performed using Simulated Annealing. This process is distributed between the nodes, hence ensures even charge depletion across the network. Randomized node selection process ensures SLP and also avoids depletion of certain specific nodes, resulting in increased network lifetime. Experiments and comparisons indicate faster route detection and optimal paths by the TLRSR model.

• The Transactions of the Korea Information Processing Society
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• v.4 no.4
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• pp.982-992
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• 1997

Almost all the software develpoment cost is especially spwnede in the test phase of kifecycle.Backtracking method and program slicing methed are often used for debugging.But these have need of abundant experience on debuggers or can't apply for large scale programs.In this paper, I used informations of design documents which is generally used, and proposed a new determination method of error positions combining backtracking method and program slcing method.I described several fundamental concepts, error classes, standard design documents and determination method of error positions to porpose a debugging method, and I explained the process of proposed method using an example program with errors.Finally, I compared and analysed the proposed method with usual slicing methods.