• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.762-764
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• 2016

The ECQV(Elliptic Curve Qu-Vanstone) is a implicit certificate scheme based on ECC(Elliptic Curve Cryptography). Implicit certificates are smaller and faster than a traditional explicit certificate. Therefore, it can be used in a memory or bandwidth constraint communication environments. Also, the butterfly key expansion algorithm is a method to issue many certificates by using only one public key. In this study, by applying the butterfly key expansion algorithm to ECQV, we suggest a new useful issuing certificate method that can be used in vehicular communication environments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.4
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• pp.744-752
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• 2017

ECQV implicit certificate reconstructs the public key from the certificate without validation of the signature unlike the explicit certificate. Like this, the certificate and the public key is implicitly validated when a public key is reconstructed from a certificate. Hence, ECQV implicit certificate is shorter than the explicit certificate due to be only comprised of the public key reconstruction data instead of the signature and the public key, and faster to reconstruct the public key from the certificate than validating the signature. Furthermore, ECQV is well suited for environments and application that resources such as memory and bandwidth are limited because it is shorter the key length, and faster the performance than other cipher cryptography due to be run on ECC. In this paper, we describe prerequisites of ECQV specified in the SECG SEC 4 and issuance of an implicit certificate, reconstruction of the public key from an implicit certificate. Also we designed and implemented ECQV, and measured the performance of it.

• Journal of computational fluids engineering
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• v.9 no.3
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• pp.39-48
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• 2004

In the present study, an efficient implementation technique of the van Leer's implicit operator is suggested in accordance with the Roe's explicit operator. By using an efficient treatment of the off-diagonal terms, which occupy most of the memory requirement for the linear system of equations, it is shown that the improved scheme only requires less than 30% of memory and is approximately 10-20% faster than the baseline scheme.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.3
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• pp.19-28
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• 1995

The explicit scheme for finite element analysis of sheet metal forming problems has been widely used for providing practical solutions since it improves the convergency problem, memory size and computational time especially for the case of complicated geometry and large element number. The explicit schemes in general use are based on the elastic-plastic modelling of material requiring large computation time. In the present work, rigid-plastic explicit finite element method is introduced for analysis of sheet metal forming processes in which plane strain normal anisotropy condition can be assumed by dividing the whole piece into sections. The explicit scheme is in good agreement with the implicit scheme for numerical analysis and experimental results of auto-body panels. The proposed rigid-plastic explicit finite element method can be used as robust and efficient computational method for prediction of defects and forming severity.

• 한국노년학
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• v.28 no.4
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• pp.925-940
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• 2008

As the proportion of old people in contemporary societies steadily increases, the influence on cognitive rehabilitation strategy of the memory deficit associated with normal and pathological aging grows greater as well. This paper reviewed the current memory rehabilitation techniques for older adults. In the first part of this article, human memory systems as a framework for understanding memory aging were considered. In the second part, research findings concerning memory performance in normal aging and Alzheimer's disease were reviewed. Finally, recent evidence for the kinds of memory rehabilitation procedures with proven efficacy were offered. The existent memory rehabilitation technique have focused on prompt of residual explicit memory, use of preserved implicit memory, utilization of memory external memory aids. A suggestion of memory training based on brain plasticity as a novel approach is offered.

• Journal of Korean Institute of Industrial Engineers
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• v.36 no.3
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• pp.193-202
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• 2010

The recommender system is a typical software solution for personalized services which are now popular in e-commerce sites. Most of the existing recommender systems are based on customers' explicit rating data on items (e.g., ratings on movies), and it is only recently that recommender systems based on implicit ratings have been proposed as a better alternative. Implicit ratings of a customer on those items that are clicked but not purchased can be inferred from the customer's navigational and behavioral patterns. In this article, a dimensionality reduction (DR) technique is newly applied to the implicit rating-based recommender system, and its effectiveness is assessed using an experimental e-commerce site. The experimental results indicate that the performance of the proposed approach is superior or at least similar to the conventional collaborative filtering (CF)-based approach unless the number of recommended products is 'large.' In addition, the proposed approach requires less memory space and is computationally more efficient.

• Korean Journal of Cognitive Science
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• v.11 no.3_4
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• pp.33-43
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• 2000

The distinction between short-term store (STS) and long-term store (LTS) has been made in the perspective of information processing. Memory system theorists have argued that memory could be conceived as multiple memory systems beyond the concept of a single LTS. Popular memory system models are Schacter & Tulving (994)'s multiple memory systems and Squire (987)'s the taxonomy of long-term memory. Those m models agree that amnesic patients have intact STS but impaired LTS and have preserved implicit memory. However. there is a debate about the nature of the long-term memory impairment. One model considers amnesic deficit as a selective episodic memory impairment. whereas the other sees the deficits as both episodic and semantic memory impairment. At present, it remains unclear that episodic memory should be distinguished from semantic memory in terms of retrieval operation. The distinction between declarative memory and nondeclarative memory would be the alternative way to reflect explicit memory and implicit memory. The research focused on the function of frontal lobe might give clues to the debate about the nature of LTS.

• 한국전산유체공학회:학술대회논문집
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• 2001.05a
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• pp.38-44
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• 2001

An efficient Gauss-Seidel time integration scheme is developed for solving the Euler and Navier-Stokes equations on unstructured meshes. Roe's FDS is used for the explicit residual computations and van Leer's FVS for evaluating implicit flux Jacobian. To reduce the memory requirement to a minimum level, off-diagonal flux Jacobian contributions are repeatedly calculated during the Gauss-Seidel sub-iteration process. Computational results based on the present scheme show that approximately $15\%$ of CPU time reduction is achieved while maintaining the memory requirement level to $50-60\%$ of the original Gauss-Seidel scheme.

• Proceedings of the Korean Society of Computer Information Conference
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• 2019.01a
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• pp.223-224
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• 2019

스마트폰 애플리케이션 시장은 단기간 비약적인 성장을 거듭했다. 여러 각종 분야에서 애플리케이션 개발을 원하는 곳이 많아졌고 그만큼 앱 개발자들을 원하는 시장이 늘어나고 있다. 본 연구는 앱 개발을 도전하려는 1인 혹은 소규모 아마추어 개발자 입장에서 관련 실력을 효과적으로 늘릴 수 있는 방법을 제공하고 전반적인 애플리케이션 개발과 환경에 관한 유익한 정보들을 쉽게 접근함으로써 조금 더 애플리케이션 개발에 관심을 갖게 되는 계기가 될 것이다. 또한 본 연구의 게임 애플리케이션은 사용자들의 명시적 기억과 암묵적 기억 훈련에 도움을 줄 수 있도록 개발하였다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.1
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• pp.88-99
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• 1996

The explicit scheme for finite element analysis of sheet metal forming problems has been widely used for providing practical solutions since it improves the convergency problem, memory size and computational time especially for the case of complicated geometry and large element number. The explicit schemes in general use are based on the elastic-plastic modeling of material requiring large computataion time. In the present work, a basic formulation for rigid-plastic explicit finite element analysis of plain strain sheet metal forming problems has been proposed. The effect of some basic parameters involved in the dynamic analysis has been studied in detail. Thus, the effective ranges of parameters have been proposed for numerical simultion by the rigid-plastic explicit finite element method. A direct trial-and-error method is introduced to treat contact and friction. In computation, sheet material is assumed to possess normal anisotropy and rigid-plastic workhardening characteristics. In order to show the validity and effectiveness of the proposed explicit scheme, computations are carried out for cylindrical punch stretching and the computational results are compared with those by the implicit scheme as well as with a commercial code. The proposed rigid-plastic exlicit finite element method can be used as a robust and efficient computational method for analysis of sheet metal forming.