• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.2
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• pp.331-339
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• 2017

This paper proposes a thread pool management technique of an websocket server that is applicable to embedded systems. WebSocket is a proposed technique for consisting a dynamic web, and is constructed using HTML5 and jQuery. Various studies have been progressing to construct a dynamic web by Apache, Oracle and etc. Previous web service systems require high-capacity, high-performance hardware specifications and are not suitable for embedded systems. The node.js which is consist of HTML5 and jQuery is a typical websocket server which is made by open sources, and is a java script based web application which is composed of a single thread. The node.js has a limitation on the performance for processing a high velocity data on the embedded system. We make up a multi-thread based websoket server which can solve the mentioned problem. The thread pool is managed by a bit register and suitable for embedded systems. To evaluate the performance of the proposed algorithm, we uses JMeter that is a network test tool.

• ETRI Journal
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• v.22 no.4
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• pp.25-31
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• 2000

Design of secure and efficient public-key encryption schemes under weaker computational assumptions has been regarded as an important and challenging task. As far as ElGamal-type encryption schemes are concerned, some variants of the original ElGamal encryption scheme based on weaker computational assumption have been proposed: Although security of the ElGamal variant of Fujisaki-Okamoto public -key encryption scheme and Cramer and Shoup's encryption scheme is based on the Decisional Diffie-Hellman Assumption (DDH-A), security of the recent Pointcheval's ElGamal encryption variant is based on the Computational Diffie-Hellman Assumption (CDH-A), which is known to be weaker than DDH-A. In this paper, we propose new ElGamal encryption variants whose security is based on CDH-A and the Elliptic Curve Computational Diffie-Hellman Assumption (EC-CDH-A). Also, we show that the proposed variants are secure against the adaptive chosen-ciphertext attack in the random oracle model. An important feature of the proposed variants is length-efficiency which provides shorter ciphertexts than those of other schemes.

• ETRI Journal
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• v.38 no.4
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• pp.724-734
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• 2016

To achieve confidentiality, integrity, authentication, and non-repudiation simultaneously, the concept of signcryption was introduced by combining encryption and a signature in a single scheme. Certificate-based encryption schemes are designed to resolve the key escrow problem of identity-based encryption, as well as to simplify the certificate management problem in traditional public key cryptosystems. In this paper, we propose a new certificate-based signcryption scheme that has been proved to be secure against adaptive chosen ciphertext attacks and existentially unforgeable against chosen-message attacks in the random oracle model. Our scheme is not based on pairing and thus is efficient and practical. Furthermore, it allows a signcrypted message to be immediately verified by the public key of the sender. This means that verification and decryption of the signcrypted message are decoupled. To the best of our knowledge, this is the first signcryption scheme without pairing to have this feature.

• The Journal of Society for e-Business Studies
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• v.1 no.2
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• pp.133-160
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• 1996

It is accomplished on the practical usage for STEP in enterprise. But they has feeble grasp of STEP, therfore it is hard to apply. That is due to take a negative policy with the lack of advertising and understanding, most of studies are going on a studentlike attitude rather than the practical usage or implementation, so they don't know exactly what is STEP, and how can they apply to their own enterprise. This paper aimed to present more detail understanding of STEP usage and practical usage of STEP data in enterprise. We describe EXPRESS that is description method of STEP, four ways of implementation method, and introduce to using ST-Developer and ST-Oracle by STEP Tools Inc. for more detail understand of STEP. Thereafter we propose practical usage of STEP with CAD systems and PDM systems on the knowledge of previous study, and propose total system implementation image on STEP data in enterprise, finally discuss conclusion and luther study issues.

• Annual Conference on Human and Language Technology
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• 2017.10a
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• pp.87-91
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• 2017

구문분석은 자연언어처리의 오랜 관심 분야로 다양한 접근방법과 알고리즘이 시도되어 계속 발전하고 있다. 하지만 기존의 접근방법은, 학습단계에서는 정답으로부터 추출된 이전 정보를 사용하고 평가 단계에서는 예측으로 이루어진 정보를 활용한다는 근본적인 차이가 있다. 이러한 차이를 극복하기 위한 다양한 시도가 있었고 그 중 동적 오라클 기법이 합리적인 시간 증가와 성능향상을 보였다. 본 연구에서는 이러한 동적 오라클 기법을 한국어 구문분석에 적용하였다. 동적 오라클 기법을 한국어에 적용할 때 고려해야하는 부분에 대해 탐구하고 실험을 통해 동적 오라클 기법을 한국어 구문분석에 적용하여 결과를 살펴보았다.

• Korean Journal of Computational Design and Engineering
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• v.8 no.1
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• pp.48-54
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• 2003

In a design-to-manufacturing environment, the product data is shared by various CAD/CAM/CAE systems with little integration or substantial data redundancy. The main purpose of this paper is to build a database containing all the features required for STEP-NC machining and to show how a STEP-NC repository can support the complete process for machining. A STEP-NC database schema has been constructed and several query functions have been built for the purpose of implementing the retrieving system of a STEP-NC database. The EXPRESS data model of ISO 14649 has been mapped to the database data definition language of the Oracle database. To apply the STEP-NC database to an industry example, the ISO 14649 part program has been stored into the STEP-NC database. To implement example scenarios, the sample query interface has been built.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.11
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• pp.2928-2940
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• 2013

Key exposure is a major threat to secure cryptosystems. To mitigate the impact caused by key-compromise attacks, a key-insulated cryptographic mechanism is a better alternative. For securing the large message communication in peer-to-peer networks, in this paper, we propose the first novel identity-based key-insulated encryption (IB-KIE) scheme with message linkages. Our scheme has the properties of unbounded time periods and random-access key-updates. In the proposed scheme, each client can periodically update his private key while the corresponding public one remains unchanged. The essential security assumption of our proposed scheme is based on the well-known bilinear Diffie-Hellman problem (BDHP). To ensure the practical feasibility, we also formally prove that the proposed scheme achieves the security requirement of confidentiality against indistinguishability under adaptive chosen-ciphertext attacks (IND-CCA2) in the random oracle model.

• Communications for Statistical Applications and Methods
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• v.26 no.6
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• pp.611-622
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• 2019

This paper considers the estimation of the long memory parameter in nonparametric regression with strongly correlated errors. The key idea is to minimize a unified mean squared error of long memory parameter to select both kernel bandwidth and the number of frequencies used in exact local Whittle estimation. A unified mean squared error framework is more natural because it provides both goodness of fit and measure of strong dependence. The block bootstrap is applied to evaluate the mean squared error. Finite sample performance using Monte Carlo simulations shows the closest performance to the oracle. The proposed method outperforms existing methods especially when dependency and sample size increase. The proposed method is also illustreated to the volatility of exchange rate between Korean Won for US dollar.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1993.04a
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• pp.369-378
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• 1993

현대의 극심한 경쟁체제속에서 제조업체의 생존여부는, 얼마나 좋은제품을 신속히 시장에 출시하느냐에 달려있으며, 이러한 경쟁력을 갖추기 위해서는 제품개발에 관련된 각종정보의 부문간 공유 및 흐름의 제어가 그 성패의 관건이라 할 수 있다. 따라서 본 연구의 목적은 삼성전자의 제품개발과정에서 발생되는 모든 기술정보를 효율적으로 관리할 수 있는 체계를 확립하고, 이 체계를 System적으로 구현하여 각종 기술정보를 생성하고, 조회하는 개발자들의 현업에 이 System을 적용하고자 하는데 있다. 본 연구에 사용된 개발 Tool은 X-terminal과 HP EWS이었고, 실제 사용자들의 운용기종은 선진각국의 Server & Client추세에 따라, DB Server로는 HP9000/865S를 채택하고, Client로는 HP EWS, X-terminal, PC386등의 기종을 적용하였다. 또한 개발언어는 'C'language를 사용하였고 DBMS는 IBM MIS와의 연계를 위해, Oracle을 이용하였다. 본 연구의 결과로써 나타나는 효과는, 외형적으로 각종 기술정보의 공유로 인한 설계품질향상과 개발 납기 단축이라 할 수 있으며, 그 내면에 있는 개발관련 각종자료 및 업무의 표준화와 도면관리System의 개발 기술확보 또한 중요한 성과라 할 수 있다.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10c
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• pp.321-324
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• 2006

일반적으로 Oracle과 같은 RDBMS에서 클라이언트가 데이터베이스를 접근하거나 관리하기 위해서는 RDBMS 서버에 리스너가 실행되어야 한다. 리스너는 네트워크를 이용해 클라이언트에서 서버로 연결하기 위한 네트워크 관리자로서, 수행정보의 전송 및 관리 기능을 수행한다. 이에 반해, 정보검색시스템에서의 시스템 기동 및 폐쇄, 데이터의 관리는 온라인이 아닌 오프라인 작업으로 이루어지는 것이 보통이다. 이는 각 시스템이 추구하는 것이 관리와 검색으로 각각 다르기 때문에 구조적인 차이가 존재한다. 정보검색관리시스템 KRISTAL은 기본적으로 정보검색엔진기반의 DBMS를 적용하였기 때문에 데이터베이스 관리도구 자체가 엔진과 밀결합된 형태가 아닌, 별도의 API로 제공되기 때문에 클라이언트가 온라인상으로 서버에게 관리 기능을 요청할 수 없는 단점이 있다. 이에 본 논문에서는 KRISTAL기반 데이터베이스 관리를 위한 KRISTAL 리스너를 제안한다. KRISTAL 리스너는 RDBMS 리스너의 일반적인 기능뿐만 아니라 KRISTAL 데이터베이스 검색 데몬 프로세스 관리, 스키마 및 테이블 관리, 백업관리, 분산검색 데몬 등 온라인으로 KRISTAL 서버를 제어할 수 있는 관리 기능을 제공한다.