• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.3
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• pp.547-552
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• 1999

In [1], it is shown that a subclass of ETBFs, which are self-dual ETBFs can be expressed as a weighted average of median subfiltered outputs. In this paper, the ETBF is extended for real-valued input. Using this result, the scale-preservation and translation-invariance properties of the ETBFs are investigated. In particular, it is shown that the ETBFs are scale-preserving if and only if it is extended self-dual.

• Nuclear Engineering and Technology
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• v.44 no.4
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• pp.405-414
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• 2012

In this paper, we propose a reliability estimation method for DI&C systems. At the system level, a fault tree model is suggested and Boolean algebra is used to obtain the minimal cut sets. At the component level, an exponential distribution is used to model hardware failures, and Bayesian estimation is suggested to estimate the failure rate. Additionally, a binomial distribution is used to model software failures, and a recently developed software reliability estimation method is suggested to estimate the software failure rate. The overall system reliability is then estimated based on minimal cut sets, hardware failure rates and software failure rates.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04b
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• pp.235-237
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• 2002

연관규칙(association rule)이란 데이터 베이스에 존재하는 속성들 사이에 유사성 또는 패턴을 기술하는 것으로, 사용자에게 데이터에 관한 유용한 조보를 줄 수 있다. 그러나, 지금가지의 연관규칙은 이진 (boolean) 데이터 베이스에 존재하는 연관규칙의 발견에 대해서 주로 연구되어 왔으며, 정량적(수치적, quantitative) 속성을 갖는 데이터에 대한 연관규칙의 연구는 미비하였다. 그 이유는 정량적 속성을 갖는 데이터를 기호적(nominal) 속성값으로 바꾼 후 연관규칙 보다 성능이 우수함을 보이고 있다. 또한 본 논문에서는 퍼지 연관규칙에서 소속함수(항목, 아이템, 속성값)의 모양과 개수를 데이터 분포에 대한 통계적 특성을 나타내는 히스토그램을 이용하여 소속함수를 자동 생성하는 효율적인 연관규칙 추출방법을 제안한다

• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.50
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• pp.183-193
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• 1999

The problem of discovering association rules has received considerable research attention and several fast algorithms for mining association rules have been developed. In this paper, we propose an efficient algorithm for mining quantitative association rules with item constraints. For categorical attributes, we map the values of the attribute to a set of consecutive integers. For quantitative attributes, we can partition the attribute into values or ranges. While such constraints can be applied as a post-processing step, integrating them into the mining algorithm can reduce the execution time. We consider the problem of integrating constraints that are boolean expressions over the presence or absence of items containing quantitative attributes into the association discovery algorithm using Apriori concept.

• Korean Journal of Computational Design and Engineering
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• v.3 no.1
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• pp.1-14
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• 1998

This paper introduces non-manifold offsetting operations, which add or remove a uniform thickness from a given non-manifold model. Since these operations can be applied to not only solids but also wireframe or sheet objects, they are potentially useful for pipeline modeling, sheet metal and plastic part modeling, tolerance analysis, clearance checking, constant-radius rounding and filleting of solids, converting of abstracted models to solids, HC too1 path generation and so on. This paper describes mathematical properties and algorithms for non-manifold offsetting. In this algorithm, a sufficient set of tentative faces are generated first by offsetting all or a subset of the vertices, edges and faces of the non-manifold model. And then they are merged into a model using the Boolean operations. Finally topological entities which are within offset distance are removed. The partially modified offsetting algorithms for wireframes or sheets are also discussed in order to provide more practical offset models.

• Journal of Ship and Ocean Technology
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• v.9 no.1
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• pp.47-63
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• 2005

In the present study, we suggest a new method for designing complex ship hull forms with multiple domain B-spline surfaces accounting for their topological arrangement, where all subdomains are fully defined in terms of form parameters, e.g., positional, differential and integral descriptors. For the construction of complex hull forms, free-form elementary models such as forebody, afterbody and bulbs are united by Boolean operation and blending surfaces in compliance with the sectional area curve (SAC) of the whole ship. This new design process in this paper is called Sectional Area Curve-Balanced Parametric Design (SAC-BPD).

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.11
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• pp.132-139
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• 1993

This paper presents a new performance-driven multi-levelizer which transforms a two-level description into a boolean network of the multilevel structure satisfied with user's costraints, such as chip area, the number of wires and literals, maximum delay, function level, fanin, fanout, etc.. The performance of circuits is estimated by reference to the informations in cell library through the cell mapping phase, and multi-levelization of circuits is constructed by the decomposition using the kernel and factoring concepts. Here, the saving cost of a common subexpression is defined to the sum of area and delay saved, when it is substituted. The experiments with MCNC benchmarks show the efficiency of the proposed method.

• Korean Institute of Interior Design Journal
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• v.23 no.4
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• pp.129-139
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• 2014

The objective of this research is to suggest new geometric possibilities in digital architecture by investigating the characteristics of hybridization in digital geometry. The research begins with theoretical background research such as defining hybridization, investigating hybrid thinking, and studying the theory of digital geometry, along with the four conceptual characteristics of hybridization that could be drawn, such as temporality, liquidity, complexity, and connectivity. Based on these characteristics, the generative method of hybrid digital geometric languages such as Blob, Particle, Morph, Loft, and Boolean was analyzed with case research in contemporary digital architecture. As a result, diverse hybrid geometric keywords were extracted; these keywords suggest potential meanings of hybridization such as accidentality, mobility, diversity, and identity. Different elements represent the "mobility" in time by the force and wave, and they are "accidentally" combined in gradual change. The united species in "diverse" characters are seamlessly connected and emerge as a new "identity." The research maximizes the generative possibilities in digital geometry and provides a theoretical basis to apply the digital hybrid methods to architectural design by suggesting the potential meanings and possibilities in hybridization.

• Journal of the Ergonomics Society of Korea
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• v.19 no.3
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• pp.61-75
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• 2000

To enhance web site's usability, it has been suggested that the depth of tree structured menus should be minimized. In this research, experimental results are reported to quantitatively compare the methods currently used for reducing the depth of menus in web sites. 25 popular web sites were selected and their menu types were categorized into four types: top menu, drop-down menu, boolean menu, and table of contents. The four types of menu were then sub-categorized into 15 different types according to their sub-menu type, existence of menu colors, and the event occurring after mouse activation. Performance tests and subjective evaluation were carried out. The results showed that there were no significant differences in terms of response time among the 15 menu types, while table of contents and drop-down in which the first and second level of menus were visible induced the least number of errors. In the subjective test, the top-menu structure with colors and presentation of its sub-menu without clicking mouse were preferred.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.1
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• pp.53-64
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• 1994

Rouge cutting process takes the major portion of machining operation using NC milling machine. Especially, most of the machining time is spent in this process when molds are machined. Therefore, an efficient algorithm for generating the tool path for rough cutting is suggested in this paper. The first step of the procedure is getting the volume to be machined by applying the Boolean operation on the finished model and the workpiece which have been modeling system. Basic principle of determining machining procedure is that a large tool should be used at the portion of the simple shape while a small tool should be used at the complex portion. This principle is realized by representing the volume to be machined by an octree, which is basically a set of hexahedrons, and matching the proper tools with the given octants. When the tools are matched with the octants, the tool path can be derived at the same time.