• Journal of KIISE:Software and Applications
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• v.32 no.4
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• pp.247-257
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• 2005

Generally, the network topology design problem is characterized as a kind of NP-hard combinatorial optimization problem, which is difficult to solve with the classical method because it has exponentially increasing complexity with the augmented network size. In this paper, we propose the efficient approach with two phase that is comprised of evolutionary computation approach based on Prufer number(PN), which can efficiently represent the spanning tree, and a heuristic method considering 2-connectivity, to solve the highly reliable network topology design problem minimizing the construction cost subject to network reliability: firstly, to find the spanning tree, genetic algorithm that is the most widely known type of evolutionary computation approach, is used; secondly, a heuristic method is employed, in order to search the optimal network topology based on the spanning tree obtained in the first Phase, considering 2-connectivity. Lastly, the performance of our approach is provided from the results of numerical examples.

• Journal of Technology Innovation
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• v.22 no.4
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• pp.117-143
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• 2014

Tracing an evolutionary technological trajectory in the macroscopic viewpoint is useful for technology policy, but not for corporate technology and intellectual property strategy. Tackling this issue, recent bibliometric studies using patents and papers have made efforts to identify more specific and detailed technological trajectory. However, these studies cannot go beyond simple description of the past trajectory. Also, identification of technology fusion and evolution relies on experts judgments. We suggest a way of identifying microscopic evolutionary technological trajectories by combining patent citation network analysis with dynamic technology tree. Also, using new indicators of generality, diversity and novelty, we can detect key technologies that can be a starting point of next generation technology and derivative technology. HVDC(High Voltage DC transmission) system technology is exemplified.

• International Journal of Control, Automation, and Systems
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• v.6 no.6
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• pp.809-817
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• 2008

Program plagiarism is widespread due to intelligent software and the global Internet environment. Consequently the detection of plagiarized source code and software is becoming important especially in academic field. Though numerous studies have been reported for detecting plagiarized pairs of codes, we cannot find any profound work on understanding the underlying mechanisms of plagiarism. In this paper, we study the evolutionary process of source codes regarding that the plagiarism procedure can be considered as evolutionary steps of source codes. The final goal of our paper is to reconstruct a tree depicting the evolution process in the source code. To this end, we extend the well-known bioinformatics approach, a local alignment approach, to detect a region of similar code with an adaptive scoring matrix. The asymmetric code similarity based on the local alignment can be considered as one of the main contribution of this paper. The phylogenetic tree or evolution tree of source codes can be reconstructed using this asymmetric measure. To show the effectiveness and efficiency of the phylogeny construction algorithm, we conducted experiments with more than 100 real source codes which were obtained from East-Asia ICPC(International Collegiate Programming Contest). Our experiments showed that the proposed algorithm is quite successful in reconstructing the evolutionary direction, which enables us to identify plagiarized codes more accurately and reliably. Also, the phylogeny construction algorithm is successfully implemented on top of the plagiarism detection system of an automatic program evaluation system.

• Journal of the Korean Operations Research and Management Science Society
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• v.32 no.2
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• pp.109-121
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• 2007

This paper focuses on algorithms based on the evolution, which is applied to various optimization problems. Especially, among these algorithms based on the evolution, we investigate the simple genetic algorithm based on Darwin's evolution, the Lamarckian algorithm based on Lamark's evolution and the Baldwin algorithm based on the Baldwin effect and also Investigate the difference among them in the biological and engineering aspects. Finally, through this comparison, we suggest a new algorithm to find more various solutions changing the genotype or phenotype search space and show the performance of the proposed method. Conclusively, the proposed method showed superior performance to the previous method which was applied to the constrained minimum spanning tree problem and known as the best algorithm.

• Fisheries and Aquatic Sciences
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• v.11 no.3
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• pp.177-181
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• 2008

Glyceraldehyde 3-phosphate dehydrogenase(GAPDH) is a key enzyme for carbohydrate metabolism in most living organisms. Recent reports and our own searches of teleost species in publicly available genomic databases have identified at least two distinct GAPDH genes in a given species. The two GAPDH genes are located on the same chromosome in teleosts, whereas they are located on the different chromosomes in mammals. Thus, we reconstructed a phylogenetic tree to better understand the evolutionary history of the GAPDH genes in the vertebrate lineage. Our phylogenetic analysis revealed unambiguously that the two GAPDH genes of teleosts are phylogenetically closely affiliated to one of the cytosolic GAPDH and spermatogenic GAPDH-S of mammals. This indicates that the two paralogous GAPDH genes shared a common ancestor and subsequently underwent a gene duplication event during early vertebrate evolution. However, GAPDH-S of teleosts showed significant differences in the polypeptide residues and tissue distribution of its mRNA transcripts from that of mammals, implying they have undergone a different history of functionalization.

• The Korean Journal of Mycology
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• v.23 no.4 s.75
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• pp.318-324
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• 1995

The evolutionary relationships of the genus Trichoderma and related taxa were assessed using partial sequencing of 18S ribosomal RNA. Phylogenetic tree divided into three major groups; 1. Saccharomyces cerevisiae-Geotrichum klebahnii-Alternaria mali group; 2. Neurospora crassa-Aspergillus-Penicillium-Chrysosporium pannorum-Scopulariopsis sp. group; 3. Trichoderma group. The genus Trichoderma seemed to be phylogenetically separated from Saccharomyces cerevisiae, Aspergillus and Penicillium groups, and have passed through it's own evolutionary pathway.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.12
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• pp.3117-3132
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• 2012

The tree topology in multicast systems has high transmission efficiency, low latency, but poor resilience to node failures. In our work, some nodes are selected as backbone nodes to construct a tree-like core overlay. Backbone nodes are reliable enough and have strong upload capacity as well, which is helpful to overcome the shortcomings of tree topology. The core overlay is organized into a spanning tree while the whole overlay is of mesh-like topology. This paper focuses on improving the performance of the application-layer multicast overlay by optimizing the core overlay which is periodically adjusted with the proposed optimization algorithm. Our approach is to construct the overlay tree based on the out-degree weighted reliability where the reliability of a node is weighted by its upload bandwidth (out-degree). There is no illegal solution during the evolution which ensures the evolution efficiency. Simulation results show that the proposed approach greatly enhances the reliability of the tree-like core overlay systems and achieves shorter delay simultaneously. Its reliability performance is better than the reliability-first algorithm and its delay is very close to that of the degree-first algorithm. The complexity of the proposed algorithm is acceptable for application. Therefore the proposed approach is efficient for the topology optimization of a real multicast overlay.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2652-2657
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• 2008

An analytical study was carried out on the flow resistance of tree-shaped channel flow architectures, based on the principle of the constructal law of evolutionary increase of flow access through the generation of better flowing configurations with two diameters in the square domain. Two types of tree-shaped configurations are optimized. The minimized global flow resistance decreases definitely as the system size, N, increases. And the best channel configurations among the first construct and second construct as a result of regarding pressure drop was selected. We also show that the freedom to morph the design and to increase its performance can be enhanced by using tree-tree configurations with $2^{nd}$ construct when N is greater than 18.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10b
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• pp.823-825
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• 2003

시간이 흐름에 따라 생화학 시스템이 변화하는 것을 기록한 데이터로부터 이 시스템의 상태 전이 및 시스템을 구성하는 각 생화학 물질간의 관계를 모델링하기 위한 방법으로 S-tree 구조를 제안한다. 이것은 주로 생화학 시스템의 동적 특성을 모델링 하기 위하여 연구되어 온 S-system을 나무 구조로 표현한 것이다. 본 논문에서는 진화 연산을 통해 주어진 시계열 데이터를 잘 설명하는 S-tree의 구조 및 그 변수들을 동시에 효과적으로 탐색하는 방법을 개발하였다. 이 방법에서는 구조 탐색을 위해 유전 프로그래밍(genetic programming)에서 사용되어 온 나무 구조의 교차 및 돌연변이 연산과 더불어 다양한 형태의 구조 탐색 연산자들을 도입하였고, 또한 동시에 알맞은 변수 값들을 찾기 위하여 확률적 돌연변이 연산을 통한 언덕 오르기(hill-climbing)를 수행한다. 제안된 방법을 효모의 혐기성 발효 데이터에 적용한 결과 주어진 시스템을 성공적으로 모델링할 수 있었다.

• Journal of the Korean Operations Research and Management Science Society
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• v.27 no.2
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• pp.33-49
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• 2002

CBM (Condition-Based Maintenance) has increasingly drawn attention in industry because of its many benefits. CBM Problem Is characterized as a state-dependent scheduling model that demands simultaneous maintenance actions, each for an attribute that influences on machine condition. This problem is very hard to solve within conventional Markov decision process framework. In this paper, we present an intelligent machine maintenance scheduler, for which a new incremental decision tree learning method as evolutionary system identification model and shortest path problem as schedule generation model are developed. Although our approach does not guarantee an optimal scheduling policy in mathematical viewpoint, we verified through simulation based experiment that the intelligent scheduler is capable of providing good scheduling policy that can be used in practice.