• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.1 s.118
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• pp.65-71
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• 2007

Tolerance analysis method for natural frequencies of multi-body systems having a equilibrium position is suggested in this paper. To perform the tolerance analysis, the Monte-Carlo Method is conventionally employed. However, the Monte-Carlo Method has some weakness; spending too much time for analysis and having a low accuracy and hard to converge in the dynamical unstable area. To resolve these problems, a tolerance analysis method is suggested in this paper. Sensitivity equations of natural frequencies are derived at the equilibrium position. By employing the sensitivity information of mass, damping and stiffness matrices, the sensitivity of natural frequencies can be calculated.

• Journal of the Semiconductor & Display Technology
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• v.6 no.3
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• pp.55-59
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• 2007

Wavelet Transform is amenable to efficient algorithms. So wavelet transform was adopted many signal processing and communication applications. For example, the wavelet transform was adopted as the transform for JPEG2000. However, Wavelet has weakness about smoothness along the contours and limited directional information. Hence, recently, some new transforms have been introduced to take advantage of this property. So we use to other transform, called contourlet transform in compression. In this paper, we propose a new method for image compression based on the contourlet transform, which has been recently introduced. Contourlet transform has a good result about images with smooth contours. Moreover, Contourlet is feasible multiresolution and multidirection expansion using non-separable filter bank. This treatise shows a good image representation after compressing using contourlet transform.

• Review of KIISC
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• v.26 no.1
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• pp.34-41
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• 2016

최근 사이버 공격은 분야와 대상을 막론하지 않고 곳곳에서 발생하고 있으며 소프트웨어의 보안 취약점을 이용한 지능적인 수법으로 지속적인 공격을 수행하는 APT 공격 또한 확산하고 있다. 이와 같은 공격을 예방하기 위해서는 공격에 직접 이용되는 소프트웨어 보안 취약점을 사전에 제거해야 한다. 소프트웨어 보안 취약점(vulnerability)의 원천 원인은 소프트웨어 허점, 결점, 오류와 같은 보안 약점(weakness)이다. 그러므로 소프트웨어에서 보안 약점은 개발 단계에서 완전히 제거하는 것이 가장 좋다. 이를 위해 소프트웨어 개발 생명주기(SDLC:Software Development Life Cycle) 전반에 걸쳐 보안성을 강화하는 활동을 수행한다. 이는 소프트웨어 배포 이후에 발생할 수 있는 보안 취약점에 대한 보안 업데이트 및 패치에 대한 비용을 효과적으로 감소시키는 방안이기도 한다. 본 논문에서는 소프트웨어 개발 단계 보안을 강화한 소프트웨어 개발 생명주기로서 시큐어 SDLC에 대한 주요 사례를 소개한다.

• Computers and Concrete
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• v.13 no.6
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• pp.749-764
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• 2014

Structural safety has always been a key preoccupation for engineers responsible for the design of civil engineering projects. One of the mechanisms of structural failure, which has gathered increasing attention over the past few decades, is referred to as 'progressive collapse' which happens when one or several structural members suddenly fail, whatever the cause (accident, attack, seismic loading(.Any weakness in design or construction of structural elements can induce the progressive collapse in structures, during seismic loading. Masonry infill panels have significant influence on structure response against the lateral load. Therefore in this paper, seismic performance and shear strength of R.C frames with brick infill panel under various lateral loading patterns are investigated. This evaluation is performed by nonlinear static analysis. The results provided important information for additional design guidance on seismic safety of RC frames with brick infill panel under progressive collapse.

• Journal of the Semiconductor & Display Technology
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• v.9 no.4
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• pp.57-61
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• 2010

The wavelet transform was adopted as the transform for JPEG2000. However, wavelet has weakness about smoothness along the contours and limited directional information. So we use to other transform, called contourlet transform in compression. Objective quality assessment methods currently used Peak signal to noise Ratio(PSNR). But that is not very well matched to perceived visual quality. So new image quality assessment is required. In this paper, we propose a new method for image compression based on the contourlet transform, which has been recently introduced. In addition we evaluated compression image quality using PSNR and SSIM. Finally contourlet transform has a good result about images with smooth contours and SSIM is good method for image evaluation compared to PSNR.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.35C no.3
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• pp.16-23
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• 1998

In this paper, we present a fast and efficient Iterative Improvement Partitioning(IIP) technique for VLSI circuits and hybrid bucket structures on its implementation. The IIP algorithms are very widely used in VLSI circuit partition due to their time efficiency. As the performance of these algorithms depends on choices of moving cell, various methods have been proposed. Specially, Cluster-Removal algorithm by S. Dutt significantly improved partition quality. We indicate the weakness of previous algorithms wjere they used a uniform method for choice of cells during for choice of cells during the improvement. To solve the problem, we propose a new IIP technique that selects the method for choice of cells according to the improvement status and present hybrid bucket structures for easy implementation. The time complexity of proposed algorithm is the same with FM method and the experimental results on ACM/SIGDA benchmark circuits show improvment up to 33-44%, 45%-50% and 10-12% in cutsize over FM, LA-3 and CLIP respectively. Also with less CUP tiem, it outperforms Paraboli and MELO represented constructive-partition methods by about 12% and 24%, respectively.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.3
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• pp.139-145
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• 1993

Partitioning is an important step in the hierarchical design of very large scale integrated circuits. In this research, a new effective partitioning algorithm based on 2-level hierarchy is presented. At the beginning, clusters are formed to reduce the problem size. To overcome the weakness of the iterative improvement techniques that the partitioning result is dependent on the initial partitioning and to consistently produce good results, the cluster-level partitioning is performed several times using several sets of parameters. Then the best result of cluster-partitioning is used as the initial solution for lower level partitioning. For each partitioning, the gradual constraint enforcing partitioning method has been used. The clustering-based partitioning algorithm has been applied to several benchmark examples and produced promising results which show that this algorithm is efficient and effective.

• Journal of Applied Reliability
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• v.17 no.3
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• pp.256-263
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• 2017

Purpose: This article provides the efficiency test results of conducting depot maintenance. Method: ANOVA (analysis of variance) and ANCOVA (analysis of covariance) tests are conducted using data obtained from Defense Logistics Integrated Information System (DELIIS). Results: The result shows that although the effect of the depot maintenance is significant, some parts do not follow the overall effect of the depot maintenance. In order to solve the problem we provide some suggestions to be improved. Conclusion: For improving the combat readiness condition of K-1 main battle tank, the maintenance policies and regulation must be revised for the parts of the weakness. In addition, the collection way of the operation and maintenance data must be redesigned.

• KIEAE Journal
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• v.11 no.2
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• pp.45-57
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• 2011

As climate change and environmental degradation become more evident, the public's concern and knowledge on sustainable development requires planners to have regards to social impacts and long term economic viability, as well as environmental impacts. The main objective of this study is to analyze existing sustainability assessment tools for single detached houses. The most widely used oversea tools are selected. From analysis on the existing assessment tools, "Impact Estimator" by Athena Institute, "Bees 4.0" by NIST, "CASBEE for Home" by JSBC, "Envest for Housing" by Energy Saving Trust, "LISA" by Center for Sustainable Technology, "SBTool" by iiSBE (International Initiative for Sustainable Built Environment), it can be seen that the current sustainability assessment programs are in need of much improvement. The selected programs are analyzed on scope of program setting & running, data input & output, assessment categories, and strength & weakness. This study is to supplement the existing sustainability assessment tools for single detached houses, and provide information for the development of web-based program to assist architects or home owners to plan sustainable houses in Korea in the schematic design stage.

• The KIPS Transactions:PartC
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• v.14C no.5
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• pp.389-394
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• 2007

Recently, a location-based threshold-endorsement(LTE) scheme is proposed to thwart bogus data injection attacks. The scheme exhibits much greater filtering power than earlier symmetric schemes and results in enhanced energy savings. In this paper, we show that LTE has fatal vulnerabilities. We also propose an improved scheme that mitigates the weakness and thereby achieves the original claims without lessening remarkable filtering power intended in LTE.