• 대한수학회지
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• 제55권3호
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• pp.623-669
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• 2018

In Donaldson-Thomas theory, moduli spaces are locally the critical locus of a holomorphic function defined on a complex manifold. In this paper, we develop a theory of critical virtual manifolds which are the gluing of critical loci of holomorphic functions. We show that a critical virtual manifold X admits a natural semi-perfect obstruction theory and a virtual fundamental class $[X]^{vir}$ whose degree $DT(X)=deg[X]^{vir}$ is the Euler characteristic ${\chi}_{\nu}$(X) weighted by the Behrend function ${\nu}$. We prove that when the critical virtual manifold is orientable, the local perverse sheaves of vanishing cycles glue to a perverse sheaf P whose hypercohomology has Euler characteristic equal to the Donaldson-Thomas type invariant DT(X). In the companion paper, we proved that a moduli space X of simple sheaves on a Calabi-Yau 3-fold Y is a critical virtual manifold whose perverse sheaf categorifies the Donaldson-Thomas invariant of Y and also gives us a mathematical theory of Gopakumar-Vafa invariants.

• 한국게임학회 논문지
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• 제1권1호
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• pp.61-67
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• 2001

This paper describes a program which learns good strategies for two-poison, deterministic, zero-sum board games of perfect information. The program learns by simply playing the game against either a human or computer opponent. The results of the program's teaming of a lot of games are reported. The program consists of search kernel and a move generator module. Only the move generator is modified to reflect the rules of the game to be played. The kernel uses a temporal difference procedure combined with a backpropagation neural network to team good evaluation functions for the game being played. Central to the performance of the program is the search procedure. This is a the capture tree search used in most successful janggi playing programs. It is based on the idea of using search to correct errors in evaluations of positions. This procedure is described, analyzed, tested, and implemented in the game-teaming program. Both the test results and the performance of the program confirm the results of the analysis which indicate that search improves game playing performance for sufficiently accurate evaluation functions.

• Communications for Statistical Applications and Methods
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• 제17권6호
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• pp.891-898
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• 2010

소프트웨어는 독립적으로 개발된 모듈들을 통합하는 개발과정을 거치며, 통합된 소프트웨어는 가용도, 소프트웨어에 내재된 결함의 제거 수 및 주어진 업무(task)들의 처리능력에 의하여 성능이 평가된다. 본 연구에서는 Lee와 Park (2003)의 마코프 불완전 수리모형을 기반으로 모듈들로 구성된 소프트웨어의 업무처리 능력을 평가할 수 있는 업무의 완전처리확률(completion probability)을 유도하며, 이와함께 개발된 소프트웨어가 출하되는 최적의 시점을 결정하는 방안을 제시하고자 한다.

• Structural Engineering and Mechanics
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• 제82권3호
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• pp.401-416
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• 2022

The aim of this study is to examine the frictionless double receding contact problem for two functionally graded (FG) layers pressed with a uniformly distributed load and resting on a homogeneous half plane (HP) using analytical and numerical methods. The FG layers are made of a non-homogeneous material with an isotropic stress-strain law with exponentially varying properties. It is assumed that the contact at the FG layers and FG layer-HP interface is frictionless. The body force of the FG layers and homogeneous HP are ignored in the study. Firstly, an analytical solution for the contact problem has been realized using the theory of elasticity and the Fourier integral transform techniques. Then, the problem modeled and two-dimensional analysis was carried out by using the ANSYS package program based on FEM. Numerical results for contact lengths and contact pressures between FG layers and FG layer-HP were provided for various dimensionless quantities including material inhomogeneity, distributed load width, the shear module ratio, and the heights of the FG layers for both methods. The results obtained using FEM were compared with the results found using the analytical formulation. It was found that the results obtained from analytical formulation were in perfect agreement with the FEM study.

• 대한수학회지
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• 제60권6호
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• pp.1233-1254
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• 2023

We introduce two subclasses of abelian McCoy rings, so-called π-CN-rings and π-duo rings, and systematically study their fundamental characteristic properties accomplished with relationships among certain classical sorts of rings such as 2-primal rings, bounded rings etc. It is shown that a ring R is π-CN whenever every nilpotent element of index 2 in R is central. These rings naturally generalize the long-known class of CN-rings, introduced by Drazin [9]. It is proved that π-CN-rings are abelian, McCoy and 2-primal. We also show that, π-duo rings are strongly McCoy and abelian and also they are strongly right AB. If R is π-duo, then R[x] has property (A). If R is π-duo and it is either right weakly continuous or every prime ideal of R is maximal, then R has property (A). A π-duo ring R is left perfect if and only if R contains no infinite set of orthogonal idempotents and every left R-module has a maximal submodule. Our achieved results substantially improve many existing results.

• 방송공학회논문지
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• 제28권1호
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• pp.79-89
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• 2023

다시점 디스플레이는 관찰자의 위치에 따라 적절한 시점의 영상을 제공할 수 있어 시청자에게 입체적인 효과를 줄 수 있는 가장 실용적인 기술로 여겨진다. 하지만 대부분의 다시점 디스플레이는 평면 형태로서 시청자가 전방의 제한된 시야각 내에서만 입체 영상을 볼 수 있는 단점이 있다. 본 논문에서는 시청 영역을 360도로 확장하여 완전 시차 시차를 제공하는 구 대칭성을 가지는 볼 렌즈를 적용한 광학계로 구성된 구형 디스플레이를 제안하였다. 제안한 시스템에서 각각의 프로젝션 렌즈는 소형 모듈화하여 어레이로 구성할 수 있으며 모듈 어레이를 볼 렌즈 주위에 구면으로 배치하여 수직, 수평 시차를 제공할 수 있다. 적용된 광학 모듈을 통해 볼 렌즈 내부 중앙에 이미지가 결상되고, 사용자는 디스플레이의 시야창을 통해 선명한 영상을 시청할 수 있다. 따라서 볼 렌즈의 구면 수차를 극복하여 넓은 시야 부피를 제공하는 360도 완전 시차 디스플레이의 실현 가능성을 실험적으로 확인하였다.

• Architectural research
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• 제18권1호
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• pp.1-12
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• 2016

This thesis explores Vitruvius and his impact upon other Renaissance architects who compare a city to a building or a building to a city, who match the city and the building into a human body, and who develop their own works. The objective of this study is to furnish an interpretation of their theory and practice through their literature and designs. In this point of view, this article takes notice of Vitruvius's six concepts coined from venustas and divides them into two parts: i.e. aesthetic quality (ordinatio, dispositio, and distributio) and technical activity (eurythmia, symmetria, and $d{\acute{e}}cor$) each. This thesis indicates that Vitruvius's successive impacts from the concepts bring about concrete design principles through proportional measurements, placing together, and hierarchic values for the former, as well as appropriate use through beautiful look, symmetrical harmony, and appropriate uses for the latter, tracking notions between a city as a house and vice versa, and either the ideas of the house or the city in the synthesis of the human body, which follows the perfect number and module based on the human body. The thesis shows that the representations of architecture and the city take place with the form of a circle and a square that express the religious belief and the cosmos, substantiating the connection between the proportions of the human body and numbers, and ultimately satisfying a concept of centrality, which is slowly extended to the enclosed plaza at the urban level from chambers, atrium, and corridors at the residence level.

• 한국컴퓨터산업학회논문지
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• 제7권5호
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• pp.455-466
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• 2006

본 논문에서는 능동형 센서를 이용하여 실사 객체에 대한 깊이 정보 및 칼라 정보를 획득하고 획득된 데이터를 이용하여 3D 객체를 생성하였다. 길이 정보를 획득하는 방법은 능동형 센서 모듈을 내장한 $Zcam^{TM}$ 카메라를 이용하였다. <중략>세 번째, 세부 파라미터를 조절하여 깊이 정보의 왜곡을 보정하고 보정된 깊이 정보를 이용하여 3D 메쉬 모델을 생성한 후, 서로 인접한 외곽 점들을 연결하여 완전한 객체 메쉬 모델을 만든다. 최종적으로, 완성된 객체 메쉬 모델에 칼라 영상 데이터의 칼라 값을 적용해 매핑 처리를 수행함으로써 3D 객체를 생성하였다. 실험을 통해 능동형 센서가 장착된 카메라로 획득한 데이터만으로 3D 객체를 생성할 수 있다는 가능성을 제시하였으며, 3차원 전용 스캐너를 이용한 것보다 데이터 획득이 간편하고 용이함을 알 수 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.176-180
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• 2001

There are several factors causing re-work in CMP process such as improper polish time calculation by operator, removal rate decline of the polisher, unstable in-suit pad conditioning, slurry supply module problem and wafer carrier rotation inconsistency. And conclusively those fundimental reason for the re-work rate increasement is mainly from the cycle time delay between wafer polish and post measurement. Therefore, Wafer thickness measurement in wet condition could be able to remove those improper process conditions which may happen during the process in comparison with the conventional dried wafer measurement system and it can be able to reduce the CMP process cycle time. CMP scrap reduction by overpolish, re-work rate reduction, thickness control efficiency also can be easily achieved. CMP Equipment manufacturer also trying to develop integrated system which has multi-head & platen, cleaner, pre & post thickness measure and even control the polish time from the calculated removal rate of each polishing head by software. CMP re-work problem such as over & under polish by target thickness may result in the cycle time delay. By reducing those inefficient factors during the process and establish of the automatic process control, CLC system need to be adopted to maximize the process performance. Wafer to Wafer Polish Time Feed Back Control by measuring the wafer right after the polish shorten the polish time calculation for the next wafer and it lead to the perfect Post CMP target thickness control capability. By Monitoring all of the processed the wafer, CMP process will also be stabilize itself.

• 한국재난정보학회 논문집
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• 제13권4호
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• pp.422-441
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• 2017

사물 인터넷을 기반으로 지하철역사의 재난 전조를 조기에 발견하고 승객들에게 피난을 유도하는 지하철 재난전조 감지 시스템 개발에 있어서 재난 발생시 상황대피 유도방법과 정확한 재난 위치 알림 및 대피경로 안내는 재난 상황에 빠른 대피와 인명피해를 최소화 할수 있는 매우 적극적인 대안이 될 수 있다. 좁은 출구밖에 없는 지하공간 구조상 소방 시설 및 장비들의 완벽한 작동을 담보하기란 쉽지 않다. 따라서 본 연구에서는 대피를 가장 효율적으로 유도할 수 있는 재난대응 EL Display 통합 보드를 개발하였으며 이를 현장 실험을 통해 실제 활용성에 대한 검토를 실험하였다. 특히, EL패널을 재난 대피유도용으로 활용한 사례가 없어 현장적용테스트를 거쳐 그 활용 가능성을 검증하였다.