• Journal of KIISE:Computer Systems and Theory
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• v.27 no.10
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• pp.861-867
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• 2000

최근 들어 계산분자생물학 분야에서 유전자 재배열 문제가 많은 관심을 끌고 있다. 특히 이러한 문제에는 전도(reversal)나 전치(transposition)와 같은 재배열 연산들이 사용되고 있다. 전도와 전치 두가지 연산을 모두 사용하는 정렬은 필요한 최소 연산 회수의 2배 이내의 연산 수행만으로 가능하다고 알려져 있다. 이 논문에서는 기존의 알고리즘을 분석하고 휴리스틱을 사용함으로써 실제 연산 수행 회수를 대폭 줄일 수 있음을 보였다. 또한, 기존의 알고리즘보다 간단한 새로운 알고리즘을 제시하고, 이 알고리즘과 휴리스틱을 같이 사용하는 경우 수행 시간과 실험적 근사비(approximation ratio)에 있어서 매우 효과적임을 보였다.

• Korean Journal of Cognitive Science
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• v.17 no.4
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• pp.323-336
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• 2006

In this paper, we present a pilot system that can extract paraphrases from a parallel corpus using to-training method. Paraphrases are useful for the applications that should rreate a varied ind fluent text, such as machine translation, question-answering system, and multidocument summarization system. One of the difficulties in extracting paraphrases is to find a rich source from which we can extract paraphrases. The bible is one of the good sources fur extracting paraphrases as it has several Korean versions in which every sentence can be easily aligned by the chapter and the verse. We ran extract not only the lexical-level paraphrases but also the phrasal-level paraphrases from the parallel corpus which consists of the bibles using co-training method.

• Journal of KIISE:Computer Systems and Theory
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• v.36 no.2
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• pp.68-72
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• 2009

The suffix array is a data structure storing all suffixes of a string in lexicographical order. It is widely used in string problems instead of the suffix tree, which uses a large amount of memory space. Many researches have shown that not only the suffix array can be built in O(n), but also it can be constructed with a small time and space usage for real-world inputs. In this paper, we analyze a practical suffix sorting algorithm due to Maniscalco and Puglisi [1], and we propose an efficient algorithm which improves Maniscalco-Puglisi's running time.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.8
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• pp.1843-1849
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• 2009

In real-time 3D Graphics, pipeline optimization is one of techniques enhancing rendering performance. Pipeline optimization is kind of buffer reordering problem, but it is NP-hard. Therefore techniques that is approximating optimal solution and suitable for real-time 3D graphics are needed. This paper analyze pattern of rendering states changing costs for real-time 3D graphics, and based on this, the algorithm that brings rendering states into line by changing costs is proposed. The proposed technique shows good performance enhancement when costs of some rendering states are much higher than others. Proposed technique shows 2.5 to 4 times better performance than non-ordering algorithm and becomes more faster when rendering costs of a state gets higher.

• Journal of KIISE:Software and Applications
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• v.36 no.4
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• pp.329-334
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• 2009

The ontology alignment has two kinds of major problems. First, the features used for ontology alignment are usually defined by experts, but it is highly possible for some critical features to be excluded from the feature set. Second, the semantic and the structural similarities are usually computed independently, and then they are combined in an ad-hoc way where the weights are determined heuristically. This paper proposes the modified parse tree kernel (MPTK) for ontology alignment. In order to compute the similarity between entities in the ontologies, a tree is adopted as a representation of an ontology. After transforming an ontology into a set of trees, their similarity is computed using MPTK without explicit enumeration of features. In computing the similarity between trees, the approximate string matching is adopted to naturally reflect not only the structural information but also the semantic information. According to a series of experiments with a standard data set, the kernel method outperforms other structural similarities such as GMO. In addition, the proposed method shows the state-of-the-art performance in the ontology alignment.

• Korean Journal of Optics and Photonics
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• v.33 no.5
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• pp.210-217
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• 2022

In this paper, a study is conducted on the acceptable tolerance of an alignment device to reduce the optical loss caused by the alignment tolerance of a window hermetic optical connector. To increase the transmission distance of optical signals and fiber-optic communication systems, it is necessary to maintain and improve the high optical efficiency of the connectors used to bond optical fibers. In the case of the window hermetic optical connector, the optical system is aligned through an alignment device. At this time, since the two connectors are used together, each component is fixed, and further alignment is impossible. The alignment tolerance of the housing system and pin used to align the optical system of the connector causes optical loss, leading to serious problems in the fiber-optic communication system. Thus, to find the acceptable tolerance required for manufacturing the optical-connector alignment device, tolerance analysis is performed on the components of the optical connector, such as the ball lens and the window. We also implement single-mode and multimode optical-connector systems, respectively. Based on the results, we determine an acceptable tolerance value for the alignment device.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.4
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• pp.395-403
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• 2012

This is direct bonding many of the metal bumps between FPCB and HPCB substrate. By using an ultrasonic horn mounted on an ultrasonic bonding machine, it is possible to bond gold pads onto the FPCB and HPCB at room temperature without an adhesive like ACA or NCA and high heat and solder. This ultrasonic bonding technology minimizes damage to the material. The process conditions evaluated for obtaining a greater bonding strength than 0.6 kgf, which is commercially required, were 40 kHz of frequency; 0.6MPa of bonding pressure; and 0.5, 1.0, 1.5, and 2.0 s of bonding time. The peel off test was performed for evaluating bonding strength, which was found to be more than 0.80 kgf.

• Journal of KIISE:Databases
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• v.33 no.6
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• pp.590-599
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• 2006

Disordered streams cause two issues in processing sliding windows: i) how to place input tuples into a buffer in an increasing order efficiently and ii) how to determine a time point to process the windows from input tuples in the buffer. To address these issues, we propose a structure and method of operators for processing sliding windows. We first present a structure of the operators using an index to handle input tuples efficiently. Then, we propose a method to determine the time point to process the windows, which is called a mean-based estimation. In the proposed method, users can describe parameters required for estimation in a query specification, which provides a way for users to control the properties of query results such as the accuracy or the response time according to application requirements. Our experimental results show that the mean-based estimation provides better adaptivity and stability than the one used in the existing method.

• Proceedings of the Optical Society of Korea Conference
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• 2003.07a
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• pp.208-209
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• 2003

고밀도 광집적회로의 광도파로는 단일모드 광섬유와 굴절률의 차이 및 코어 크기에 의해 모드 부정합 문제가 존재한다. 본 논문은 이러한 모드 부정합 문제를 해결할 수 있는 모드 크기 변환기를 설계 하고 3-D Beam Propagation Method (BPM)을 이용하여 분석하였다. 모드 크기 변환기술에는 마이크로 렌즈, 테이퍼 광섬유, 렌즈화 광섬유가 사용되고 있으나 이는 패키징 가격이 높으며 광섬유와의 정렬 문제가 존재하므로, 집적된 실리콘 기판위에 제작하는 모드 크기 변환기에 대한 연구가 다각도에서 시도되고 있다. (중략)

• Journal of Intelligence and Information Systems
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• v.17 no.2
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• pp.1-22
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• 2011

In this paper, we propose an adaptive genetic algorithm (aGA) approach for effectively solving the sequencing problem with precedence constraints (SPPC). For effective representation of the SPPC in the aGA approach, a new representation procedure, called the topological sort-based representation procedure, is used. The proposed aGA approach has an adaptive scheme using a fuzzy logic controller and adaptively regulates the rate of the crossover operator during the genetic search process. Experimental results using various types of the SPPC show that the proposed aGA approach outperforms conventional competing approaches. Finally the proposed aGA approach can be a good alternative for locating optimal solutions or sequences for various types of the SPPC.