• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.5
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• pp.249-257
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• 2022

This paper presents an improved computational framework for the direct-solution-based finite element tearing and interconnecting (FETI) algorithm. The FETI-local algorithm is further improved herein, and localized Lagrange multipliers are used to define the interface among its subdomains. Selective inverse entry computation, using a property of the Boolean matrix, is employed for the computation of the subdomain interface stiffness and load, in which the original FETI-local algorithm requires a full matrix inverse computation of a high computational cost. In the global interface computation step, the original serial computation is replaced by a parallel multi-frontal method. The performance of the improved FETI-local algorithm was evaluated using a numerical example with 64 million degrees of freedom (DOFs). The computational time was reduced by up to 97.8% compared to that of the original algorithm. In addition, further stable and improved scalability was obtained in terms of a speed-up indicator. Furthermore, a performance comparison was conducted to evaluate the differences between the proposed algorithm and commercial software ANSYS using a large-scale computation with 432 million DOFs. Although ANSYS is superior in terms of computational time, the proposed algorithm has an advantage in terms of the speed-up increase per processor increase.

• Journal of the Korean Institute of Telematics and Electronics
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• v.5 no.4
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• pp.1-8
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• 1968

A TANT network is a three-level network composed solely of NAND gates having only true(i.e. uncomplemented) inputs. The paper presents a technique for finding for any given Boolean function a least-cost TANT network. The first step of the technique is to determine essential prime implicants(EPI) by Quine-McCluskey procedure or other methods and generate prime implicants(PI) hving the same head as any one of EPI by consensus operation. The second step is to select common factors among the usable tail factors. The selcetion phase is analogous to the use of C-C table. The last step is to minimize inputs by deleting the redundant PI. the technique permits hand solution of typical five-and six-variable problems.

• Journal of the Korean Society for Library and Information Science
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• v.32 no.4
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• pp.209-225
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• 1998

This research focuses on how users behave when they search by subject using online public access catalog(OPAC). Major findings are as follows. 1)Main access poults are subject field$(55.2\%)$and title field$(42.2\%)$. 2) The search failure rate in subject searching is $59.3\%$. 3) Ma]or reasons for subject search failures are two-fold : use of inappropriate search terms $(48.5\%)$ and non-use of Boolean Operators$(42.5\%)$. 4) In order to overcome search failures users tend to change originally used search terms$(42.0\%)$ and search fields$(33.8\%) into different ones.

• Journal of the Korean Society for information Management
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• v.11 no.1
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• pp.81-102
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• 1994

Accordmg to the development of various information retneval system suitable for Korean database, many researchers have realized the need of R Test ColleAon which can be r d y used for evaluatmg a retneval system. Therefore, This study developed the TEST SET whch helps ob&vely evaluatmg the retrieval performance of an Hangul Automatic Indexer or Korean Information Retrieval System. The developed Test Set has four files such as: 1) Korean Document Set( * . all): 2) Natural Language Query Set(KTsetnq1): 3) Boolean Query Set(Ktset.bq1): 4) Query-Relevance Judgment Set ( KTsetrel) .

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.952-954
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• 2005

D-클래스는 $n{\times}n$ 불리언 행렬의 집합에서 특정 관계(relation)에 따딸라 동치(equivalent) 관계에 있는 불리언 행렬의 집합으로 구성된다. D-클래스 계산은 $n{\times}n$ 불리언 행렬의 전체 집합을 대상으로 이 집합에서 조합할 수 있는 모든 두 $n{\times}n$ 불리언 행렬 사이의 곱셈을 기본적으로 요구한다. 그러나 불리언 행렬에 대한 대부분의 연구는 두 개의 불리언 행렬에 대한 효율적인 곱셈에 집중되었으며 모든 $n{\times}n$ 불리언 행렬 사이의 곱셈에 대한 연구는 최근에야 소수가 보이고 있다. 두개의 $n{\times}n$ 불리언 행렬 곱셈에 대해 최적화된 알고리즘은 현재 알려져 있으나, 모든 $n{\times}n$ 불리언 행렬 사이의 곱셈에 대해 제시된 알고리즘은 아직 실행시간이 크게 향상되지 못하고 있으며 많은 개선과 연구가 필요하다. 본 논문은 개별적인 $n{\times}n$ 불리언 행렬 곱셈 대신 하나의 $n{\times}n$ 불리언 행렬과 불리언 행렬 집합과의 곱셈을 다루고 또한 이 곱셈에서 계산되는 모든 $n{\times}n$ 불리언 행렬을 집합으로 표현하는 방법을 통해 D-클래스 계산을 보다 효율적으로 할 수 있는 알고리즘에 대해 논한다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.2 s.233
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• pp.333-340
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• 2005

Feedrate is one of the factors that have the significant effects on the productivity, qualify and tool life in the cutting mechanism as well as cutting velocity, depth of cut and width of cut. In this study, in order to realize the high-efficient machining, a new feedrate optimization method is proposed based on the concept that the optimum feedrate can be derived from the allowable cutting power since the cutting power can be predicted from the cutting parameters as feedrate, depth of cut, width of cut, chip thickness, engagement angle, rake angle, specific cutting force and so on. Tool paths are extracted from the original NC program via the reverse post-processing process and converted into the infinitesimal tool paths via the interpolation process. And the novel NC program is reconstructed by optimizing the feedrate of infinitesimal tool paths. Especially, the fast feedrate optimization is realized by using the Boolean operation based on the Goldfeather CSG rendering algorithm, and the simulation results reveal the availability of the proposed optimization method dramatically reducing the cutting time and/or the optimization time. As a result, the proposed optimization method will go far toward improving the productivity and qualify.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1302-1306
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• 2004

This paper proposes a model for information filtering (IF) on the Web. The user information need is described into two levels in this model: profiles on category level, and Boolean queries on document level. To efficiently estimate the relevance between the user information need and documents by fuzzy, the user information need is treated as a rough set on the space of documents. The rough set decision theory is used to classify the new documents according to the user information need. In return for this, the new documents are divided into three parts: positive region, boundary region, and negative region. We modified user profile by the user's relevance feedback and discerning words in the documents. In experimental we compared the results of three methods, firstly is to search documents that are not passed the filtering system. Second, search documents that passed the filtering system. Lastly, search documents after modified user profile. The result from using these techniques can obtain higher precision.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2005.09a
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• pp.202-205
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• 2005

Cell phenotypes are determined by the concerted activity of thousands of genes and their products. This activity is coordinated by a complex network that regulates the expression of genes. Understanding this organization is crucial to elucidate cellular activities, and many researches have tried to construct gene regulatory networks from mRNA expression data which are nowadays the most available and have a lot of information for cellular processes. Several computational tools, such as Boolean network, Qualitative network, Bayesian network, and so on, have been applied to infer these networks. Among them, Bayesian networks that we chose as the inference tool have been often used in this field recently due to their well-established theoretical foundation and statistical robustness. However, the relative insufficiency of experiments with respect to the number of genes leads to many false positive inferences. To alleviate this problem, we had developed the algorithm of MONET(MOdularized NETwork learning), which is a new method for inferring modularized gene networks by utilizing two complementary sources of information: biological annotations and gene expression. Afterward, we have packaged and improved MONET by combining dispersed functional blocks, extending species which can be inputted in this system, reducing the time complexities by improving algorithms, and simplifying input/output formats and parameters so that it can be utilized in actual fields. In this paper, we present the architecture of MONET system that we have improved.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.6
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• pp.621-626
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• 2010

For geometric correction of high-resolution images, the authors matched corresponding objects between a large-scale digital map and a QuickBird image to obtain the coefficients of the first order polynomial. Proximity corrections were performed, using the Boolean operation, to perform automated matching accurately. The modified iterative closest point (ICP) algorithm was used between the point data of the surface linear objects and the point data of the edge objects of the image to determine accurate transformation coefficients. As a result of the automated geometric correction for the study site, an accuracy of 1.207 root mean square error (RMSE) per pixel was obtained.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.6 s.183
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• pp.151-159
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• 2006

This paper describes a design process of end-milling cutters: solid model of the designed cutter is constructed along with computation of cutter geometry, and the wheel geometry as well as wheel positioning data f3r fabricating end-mills with required cutter geometry is calculated. In the process, the main idea is to use the cutting simulation method by which the machined shape of an end-milling cutter is obtained via Boolean operation between a given grinding wheel and a cylindrical workpiece (raw stock). Major design parameters of a cutter such as rake angle, inner radius can be verified by interrogating the section profile of its solid model. We studied relations between various dimensional parameters and proposed an iterative approach to obtain the required geometry of a grinding wheel and the CL data for machining an end-milling cutter satisfying the design parameters. This research has been implemented on a commercial CAD system by use of the API function programming, and is currently used by a tool maker in Korea. It can eliminate producing a physical prototype during the design stage, and it can be used for virtual cutting test and analysis as well.