• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2007.11a
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• pp.464-467
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• 2007

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.12
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• pp.2962-2969
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• 1993

Recently, a study on the mirror-like surface grinding of brittle materials is active and as branch of these study, new dressing method for superabrasive wheel, electrolytic inprocess dressing(Elid) was developed. Using Elid, the mirror-like surface of brittle material can be generated without polishing or lapping process. In the future, Elid grinding will take important place in industry. But so far the analysis on Elid grinding was not quantitative but qualitative. In this study, The purpose is the quantitative analysis on Elid grinding by computer simulation, For computer simulation, the mean and the variance of the abrasive distribution were measured by tracing of the grinding wheel with stylus in transverse direction in the case of respective dressing current condition. This measurement result in a density distribution of abrasive by mathematical formulation using statistical method. The prediction of the surface roughness in Elid grinding was based on this density distribution.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06a
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• pp.494-497
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• 2011

함수 복귀 예측은 이론적으로 오버플로가 발생하지 않는 한도 내에서 100%의 정확도를 보여야 한다. 하지만, 투기적 실행을 지원하는 현대 마이크로프로세서 환경 하에서는 잘못된 실행 경로로의 수행 결과를 무효화 할 때 RAS의 오염이 발생하며, 이는 함수 복귀 주소의 예측 실패로 이어진다. 본 논문에서는 이러한 RAS의 오염을 방지하기 위하여 RAS 재명명 기법을 제안한다. RAS 재명명 기법은 RAS의 스택을 소프트 스택과 하드 스택으로 나누어 관리한다. 소프트 스택은 투기적 실행에 의한 데이터의 변경을 복구할 수 있는 항목을 관리하고, 하드 스택은 소프트 스택의 크기 제한으로 겹쳐쓰기가 일어나는 데이터 가운데 이후에 재사용될 데이터를 관리하는 구조로 구성된다. 제안된 기법을 모의실험 한 결과, RAS 오염방지 기법이 적용되지 않은 시스템과 비교하여 함수 복귀 예측 실패를 약 1/90로 감소시켰으며, 최대 6.95%의 IPC 향상을 가져왔다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.8C
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• pp.569-574
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• 2008

Noise predictive maximum likelihood(NPML) detector embeds noise prediction! whitening process in the branch metric calculation of Viterbi detector and improves the reliability. In this paper, some high-density optical storage channels are examined, and appropriate NPML systems are designed for each channel.

• Journal of Construction Engineering and Project Management
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• v.4 no.3
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• pp.47-52
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• 2014

In the last decades, Facility Management (FM) has established itself as a key building service factor.FM includes supporting services and organizing functions essential for maintaining, operating and managing physical component and material. The purpose of the paper is to develop an economical analysis for building facilities management during its service life based on limited cost. This method helps to facilities managers and engineers to make better decisions for reducing of facilities assessment costs and increasing the facilities' service life. This paper presents the preliminary development of a model involves three stages process namely data collection, economic computation and economic process optimization. This process was tested for fiberglass doors example in a building interior and exterior system. If executives can manage essential points effectively and make decisions according to a key performance index, cost can be optimized and safety can be enhanced for installation building.

• Journal of Distribution Science
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• v.12 no.3
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• pp.33-41
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• 2014

Purpose - The purpose of this study was to predict the selection of independent auditors in the companies listed on the Tehran Stock Exchange (TSE) using a combination of PSO algorithm and CART. This study involves applied research. Design, approach and methodology - The population consisted of all the companies listed on TSE during the period 2005-2010, and the sample included 576 data specimens from 95 companies during six consecutive years. The independent variables in the study were the financial ratios of the sample companies, which were analyzed using two data mining techniques, namely, PSO algorithm and CART. Results - The results of this study showed that among the analyzed variables, total assets, current assets, audit fee, working capital, current ratio, debt ratio, solvency ratio, turnover, and capital were predictors of independent auditor selection. Conclusion - The current study is practically the first to focus on this topic in the specific context of Iran. In this regard, the study may be valuable for application in developing countries.

• Proceedings of the Korea Water Resources Association Conference
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• 1991.07a
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• pp.221-230
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• 1991

Various Models of the moisture content-capillary pressure hysteresie based on the approach of domain concept in porous media are compared with each other, Model III-1(Mualem, 1984) is superio to others as expected. A new model based on Model III-1 is proposed of which asuumption is the linearization of P$$($\theta$) accounting for the pore blockage effect against air-entry. The feature of this model is that only one branch of boundary curve is needed to calibrate it, which is the advantage to Model III-1. The prediction of boundary drying curve from boundary wetting curve using this model is better than that using Model I-1, II-1 compared with the experimental data. This model is to simulate scanning curves, while Model I-1, II-1 is not.

• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.1
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• pp.48-59
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• 2018

This paper is mainly concerned with developing the formulae of predicting thermal deformation of steel plate due to multi-line heating. By investigating the results of line heating test and numerical analysis, reasonable heat flux model has been defined. Formulae of predicting the transverse shrinkage and the angular distortion as the dominant thermal deformation types in plate forming by line heating have been derived based on the results of line heating test and numerical analysis with varying plate thickness, heating speed and distance between torches. This paper illustrates how the derived formulae are used in investigating the effect of multi-line heating upon the thermal deformation and how they can be used in defining the limit distance with that there is no interacted effect between torches. This paper ends with describing the extension of the present study.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.10a
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• pp.456-458
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• 2019

정보보안을 달성하기 위해서 컴퓨터가 보급된 이래로 많은 노력이 이루어졌다. 그중 메모리 보호 기법에 대한 연구가 가장 많이 이루어졌지만, 컴퓨터의 성능 향상으로 이전의 메모리 보호 기법들의 문제들이 발견되고, 부채널 공격의 등장으로 새로운 방어책이 필요 되었다. 본 논문에서는 프로그램에 정적 바이너리 재작성(Static Binary Rewriting) 기법을 통해 페이지(Page)마다 4~8byte 의 난수를 삽입하여 메모리 공유 기반 부채널 공격을 방어할 수 있는 2 가지 방법을 제시한다. 최근 아키텍처는 분기 예측(Branch Prediction)을 통해 jmp 명령어에 대한 분기처리가 매우 빠르고 정확하게 처리되기 때문에 난수를 삽입할 때 사용하는 jmp+rand 방식은 오버헤드가 매우 낮다. 또한 특정 프로그램에만 난수 삽입이 가능하므로 특히 클라우드 환경에서 중복제거 기능과 함께 사용하면 높은 효율성을 보일 수 있다고 예상한다.

• Structural Engineering and Mechanics
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• v.10 no.2
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• pp.165-180
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• 2000

An analytical model with tension softening for the prediction of the capacity of prestressed concrete beams under pure torsion and under torsion combined with shear and flexure is introduced. The proposed approach employs bilinear stress-strain relationship with post cracking tension softening branch for the concrete in tension and special failure criteria for biaxial stress states. Further, for the solution of the governing equations a special numerical scheme is adopted which can be applied to elements with practically any cross-section since it utilizes a numerical mapping. The proposed method is mainly applied to plain prestressed concrete elements, but is also applicable to prestressed concrete beams with light transverse reinforcement. The aim of the present work is twofold; first, the validation of the approach by comparison between experimental results and analytical predictions and second, a parametrical study of the influence of concentric and eccentric prestressing on the torsional capacity of concrete elements and the interaction between torsion and shear for various levels of prestressing. The results of this investigation presented in the form of interaction curves, are compared to experimental results and code provisions.