• Proceedings of the Korean Information Science Society Conference
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• 2001.10c
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• pp.844-846
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• 2001

홈기반의 분산 공유메모리 모델은 지금 현재 가장 적은 외부 통신비용을 가진 프로토콜 모델이다. 본 논문에서는 기존의 Recoverpoint와 Recoverpoint Server를 이용한 결함허용모델 (Checkpoint Model)을 보다 향상시키기 위하여 향상된 결함복구후 재실행 알고리즘을 제안한다. 이 알고리즘은 피기백(Piggyback)방식과 복수개의 Checkpoint를 사용하며 기존의 Vector Time Stamp 기법시스템보다 더 낳은 확장성과 실행속도를 제공한다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10a
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• pp.322-324
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• 2004

보안 시스템은 암호화 기능을 필요로 하고 암호화를 위 한 비밀키로 난수를 사용한다 난수 발생기에는 순수 난수 발생기와 의사 난수 발생기가 있다. 본 논문에서는 펜티엄부터 인텔 프로세서들이 가지고 있는 타임스탬프 카운터 레지스터(TSC MSR)에서 시드를 가져와 비트 가공을 통해 난수를 발생하는 난수 발생기를 구현하였다. 구현된 난수 발생기의 난수 품질을 평가하기 위해 순수 난수 발생기, 의사 난수 발생기의 난수 시퀀스와 비교하였다. 구현된 난수 발생기가 생성한 난수 시퀀스는 순수 난수 발생기의 난수 시퀀스와 큰 차이가 없고 특정 디바이스 없이 응용이 간단하다는 점에서 보안 시스템의 암호화키로 사용하기에 적합하다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.403-404
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• 2010

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1998.06a
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• pp.65-73
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• 1998

The design analysis of axisymmetric, multi-stage deep drawing dies was performed using the rigid-viscoplastic finite element formulation. In the formulation, the axisymmetric CFS algorithm was employed. Hill's non-quadratic normal anisotropic yield criterion and isotropic hardening rule were considered. For trial initial displacements and tool contact points, the geometric force equilibrium method was adopted. In order to see the validity of the formulation, the multi-stage deep drawing processes of shell-cylinder front part of hydraulic booster were simulated. The simulation showed good agreements with measurements and PAM-STAMP.

• Proceedings of the Korea Multimedia Society Conference
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• 2002.05c
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• pp.68-72
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• 2002

CIS 응용에서 공간 객체들이 여러 사이트에 걸쳐 중복 저장되어 있다면, 이 객체들의 수정 시 일관성 제어를 위한 중복 제어 기법이 필요하다. 그러나, 일반적인 비즈니스 데이터를 위한 정통적인 중복 제어기법은 공간 데이터에는 그대로 사용될 수 없다. 공간 데이터의 수정은 긴 트랜 션을 필요로 하며, 또한 일반 데이터와 달리 데이터간의 공간 종속성을 지니기 때문이다. 본 논문은 기존의 Primary Copy 중복 제어 기법을 확장하며, time-stamp에 기반하여 Primary Copy 사이트가 변경되는 Floating Primary Copy 기법을 제안한다. 본 논문에서 제안하는 중복 제어 기법은 Primary Copy 사이트를 동적으로 변경함으로써, 긴 트랜 션의 중복 일관성 제어를 지원할 수 있다.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.861-864
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• 2012

타임스탬프 서비스 형태에서 서비스제공자, 이용자에 따라 현재의 타임스탬프 모델보다 보안의 강도를 높이면서 최적의 성능을 보장할 수 있도록 모델을 설계하고 비교 분석한다. 문서를 그룹하여 타임스탬프를 발급 받으려는 이용자는 Multi Linear Hash Tree 구조를 제안하고 타임스탬프 서비스 제공업체는 Multi Prefix 이진 트리 구조를 제안한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.617-619
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• 2013

대표적인 마케팅 전략 중에 하나인 종이스탬프는 관리와 휴대가 불편하고 정산 과정과 처리가 힘들어서 효과적인 관리 방안이 필요하다. 따라서 본 논문에서는 사용자나 가맹점에서 스마트기기를 이용하여 스탬프을 적립하고 휴대와 관리를 보다 손쉽게 할 수 있는 시스템을 설계하였다.

• Journal of KIISE:Databases
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• v.30 no.6
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• pp.606-628
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• 2003

Recently, there have been many research efforts reported in the literature that focus on the cache consistency problems of mobile clients resulting from their frequent disconnections with a server in mobile environments. To cope with this problem, a number of methods based on the invalidation report scheme has been proposed. However, these proposed methods are sensitive to the disconnection time of mobile clients and independent of the frequency of data updates in the server. As a result, although the number of data updated in the server is small, the traditional methods can not guarantee the cache consistency of mobile clients if their disconnection time is over the time period the invalidation report is allowed to cover. In this paper, we propose an efficient cache consistency method called CCI(Cost-based Cache Invalidation) for mobile clients that take into account not only the disconnection time but also the frequencies of data updates in the server We also present an in-depth experimental analysis by comparing CCI method with BT(Broadcasting Time stamp) method based on Invalidation Report.

• Journal of the Ergonomics Society of Korea
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• v.36 no.5
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• pp.485-498
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• 2017

Objective: This study aims to survey and compare three systemic accident investigation techniques of Accimap, STAMP and FRAM, based on the application studies of the Sewol ferry accident. Background: Traditional accident investigation methods such as domino models, FTA, etc. work well for losses caused by physical component failures or actions of human in relatively simple systems, but are unable to depict mechanisms generating errors and violations in the current complex socio-technical systems. For better understanding the structure and behavior of the socio-technical systems, systemic techniques have been developed and used. Method: This study was mainly based on survey of literatures through surfing webpages of ScienceDirect and Google, and ergonomics relevant journals. The key words of Sewol, Sewol ferry, Sewol ferry accident, etc. were used in the survey. Results: Three systemic accident investigation methods included similar actors in the Sewol ferry accident including government, Ministry of Ocean and Fisheries, Korean Coast Guard, Korean Register of Shipping, Korea Shipping Association, Chonghaejin Marine Company, crew members. The methods graphically represented each level's failures or performance variabilities of relevant functions and relationships between them. It was shown that the systemic methods consider the entire system, ranging from the environment in which the accident occurred, to the role of government in shaping the system of work. Each method has its own comparative pros and cons, but the Accimap has advantages in terms of time of analysis, data required, model complexity and degree of comprehensiveness. Conclusion: This study reviewed and compared three systemic accident investigation methods, which showed that there are systemic characteristics and pros and cons in the methods. Application: The results would be used as a guideline when selecting accident investigation methods.

• Journal of Digital Contents Society
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• v.8 no.2
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• pp.205-211
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• 2007

The marketing using coupons policy is using in various business departments. The coupon marketing gives advantages to consumers and stores, too. The coupon policy gives discount to consumers. The stores can reduce cost of advertisement. It activates the motivation of consumers to give his loyalty to the specific store. Although the coupon marketing has these merits, there are too many coupons in the purse of consumers. The consumers should collect their coupons in their purse. The shops have to calculate the points of each consumer's coupons differently. The processing process of coupons is too complex to manage. This paper implements the managing system to control stamps in mobile devices. "Collecting Stamp" resolves those problems and enables to manage various coupons in mobile environment.