• Proceedings of the Korea Society for Simulation Conference
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• 1999.10a
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• pp.87-92
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• 1999

교차로 접근지체의 산정은 간선도로의 서비스수준 평가에 있어서 가장 중요한 요소 중의 하나이다. 교차로 접근지체는 상류부 교차로에서 진입하는 교통에 대한 균일지체와 그 이외 단일로 상에 존재하는 세가로등에서 유입되는 교통에 대한 무작위지체, 1회의 신호주기에 교차로를 통과하지 못한 교통에 대한 잔여지체 등과 연동보정계수를 이용하여 산정된다. 우리나라를 비롯한 대부분의 나라에서는 미국에서 차량의 지체와 연동보정계수를 이용하여 개발된 교차로 접근지체 산정식의 구조를 그대로 수용하고 있다. 그러나 도심부 신호교차로 사이의 단일로에 보행자를 위한 횡단신호가 설치되어 있는 경우, 이러한 단일로 횡단신호가 하류부 교차로의 접근지체에 미치는 영향이 있을 것으로 판단한다. 따라서 미국과는 달리 신호교차로간의 간격이 크고, 단일로 상에 보행자용 횡단시호 설치가 빈번한 우리나라의 실정에서는 이에 대한 영향을 분석하여 교차로 접근지체 산정 시 이를 반영하는 것이 바람직하다. 본 연구에서는 단일로 횡단신호가 하류부 신호교차로에서의 접근지체에 미치는 영향을 분석하기 위하여, 상류부 교차로와 단일로 중간부 횡단보도와의 거리, v/c 비, 신호 offset 등 상황을 설정하여 TRANSYT-7F를 이용하여 시뮬레이션을 수행하였다. 본 연구에 의하면 단이로 중간의 횡단신호가 상류부 교차로의 신호와 연동되지 않는 경우에는 하류부 교차로의 접근지체에 미치는 영향이 거의 없는 것으로 나타났으며, 연동 시에는 상류부 교차로와의 거리, v/c 비, 신호 offset 등에 따라 최고 80% 이상 까지 접근지체가 증가하였다. 일반적으로 신호 offset이 40%에서 60% 사이로 연동상태가 불량할수록 하류부 교차로에서의 접근지체가 증가하는 것으로 나타났으며, 그 외에 변수에 대하여서도 신호 offset에 따라 다른 정도로 접근지체에 영향을 미치는 것으로 나타났다. 따라서 현재 우리나라의 신도시 개발 시 일반적으로 나타나는 대규모 구획(super block)과 이로 인하여 불가피한 단일로 중간부의 횡단신호의 설치는 교통운영 측면에서 재고되어야 할 것으로 판단된다.

• The KIPS Transactions:PartC
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• v.12C no.5 s.101
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• pp.643-648
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• 2005

Intranet system for use within an organization, usually a corporation, is to basically pass through user authentication, but information can be leaked, modified, and deleted by malevolent users who disguise an authorized user or due to user's mistakes in using various functions of web browser. Thus, there is a need for measures to protect the information from illegal use, transformation through partial modification, and illegal leakage such as fraudulent use. This paper presents a flexible Web Security Access Control system based ACM which Provide efficient suity Policy to Protect information in intranet. This Web Security Access Control system not only enhances security by Performing encryption/decryption of information in intranet but also, for sharing confidential information among departments, performs effective and useful access control by assigning different authority to the secured web page. And, by controlling the functions of client PC in various ways, information leakage on malicious purpose or by mistake can be prevented.

• The KIPS Transactions:PartC
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• v.15C no.6
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• pp.455-468
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• 2008

In this paper, we propose FAS model for establishing trust based on digital certificates in Grid security framework. The existing RBAC(Role Based Access Control) model is extended to provide permissions depending on the users‘ roles. The FAS model is designed for a system independent integrated Grid security by detailing and extending the fundamental architecture of user, role, and permission. FAS decides each user’s role, allocates access right, and publishes attribute certificate. FAS is composed of three modules: RDM, PCM, and CCM. The RDM decides roles of the user during trust negotiation process and improves the existing low level Grid security in which every single user maps a single shared local name. Both PCM and CCM confirm the capability of the user based on various policies that can restrict priority of the different user groups and roles. We have analyzed the FAS strategy with the complexity of the policy graph-based strategy. In particular, we focused on the algorithm for constructing the policy graph. As a result, the total running time was significantly reduced.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.10
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• pp.821-829
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• 2020

Health management system of airborne software repairs runtime errors to provide safety and to reduce cost of maintenance. It is critical to on-the-fly repair order violation errors, because it is difficult to identify them at the development phase. Previous work, called Repairing Atomicity Violations (Repairing-AV) diagnoses order violations for each access event by comparing execution order of accesses. As a result, Repairing-AV has time overhead that is proportional to the number of access events to shared variable. This paper presents a tool called On-the-fly Repairing System (ORS) that can repair order violations of object methods containing access events. The ORS diagnoses order violations by using correct order of object methods, and treats them by stalling its thread where the error is about to occur. Experimentation with five synthetic programs shows that ORS is more efficient than Repairing-AV when the number of access events is greater than sixty.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.4
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• pp.1035-1044
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• 1998

A new multi-channel access scheme and the associated network architecture for a single-hop WDM local area network is proposed in this paper. The proposed architecture has Central Scheduling Node (CSN) for the transmission coordination among many users, which is one of the key issues in single-hop WDM networks. The data channels, source nodes, and destination nodes are selected at CSN in very simple menner. Our scheme can relive the control processing overhead at all nodes in the network which is caused in existing distributed scheduling algorithms. CSN is simple in the architecture can be implemented easily. in respect to the network performance, the maximum obtainable throughput is up to that of the ideal output queuing because of collision free scheduling. We use the MQMS (multi-queue multi-server) model for performance analaysis.

• The KIPS Transactions:PartC
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• v.13C no.4 s.107
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• pp.521-532
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• 2006

WebDAV is an IETF standard protocol which support asynchronous collaborative authoring on the Web. The recently published WebDAV Access Control Protocol provides various methods of controlling the resources on a WebDAV server and their properties, helping high-level group activities to be performed through the WebDAV server. Based on the WebDAV access control protocol, we developed Group Workspaces which support exchanging and/or sharing data among the group members. Any member of a Group Workspace can create and share resources among the members. Also, any member can add, change or delete the resources. To support the Group Workspaces, we developed a client application named GroupExplorer, which solely supports Group Workspaces. We constructed the server for Group Workspaces using Jakarta Slide - a WebDAV server supporting the WebDAV Access Control Protocol.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.16 no.3
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• pp.87-99
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• 2006

In this paper, we propose a method of conditional access control for encrypted SVC(scalable video coding) bitstream. The main purpose of the proposition is to provide a SVC suitable encryption algorithm and a efficient method for conditional access control using encrypted SVC bitstream. We analyzed requirements for conditional access control of a SVC bitstream. And based on the analysis, we proposed encryption algorithm suitable for SVC bitstream and a method of conditional access control of the encryped bitstream. The proposed conditional access control for encrypted SVC bitstream is performed by bitsream extraction and selective decryption. We verified the usefulness of the proposed method through experiments.

• Journal of Korea Society of Industrial Information Systems
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• v.26 no.1
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• pp.55-65
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• 2021

In this paper, a methodology for reinforcing reverse logistics (RL) activities in a closed-loop supply chain (CLSC) model is proposed. For the methodology, the activities of the recovery center (RC) which can be considered as one of the facilities in the RL are reinforced. By the reinforced activities in the RC, the recovered parts and products after checking and recovering processes of the returned product from customer can be reused in the forward logistics (FL) of the CLSC model. A mathematical formulation is suggested for representing the CLSC model with reinforced RL activities, and implemented using a hybrid genetic algorithm (HGA) approach. In numerical experiment, two different scales of the CLSC model are presented and the performance of the HGA approach is compared with those of some conventional approaches. The experimental results show that the former outperforms the latter in most of performance measures. The robustness of the CLSC model is also proved by regulating various rates of the recovered parts and products in the RC.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.175-177
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• 1998

분산 컴퓨팅 환경에서 응용 프로그램들은 다른 응용 프로그램들과 자원을 공유하고 통신하면서 보다 효율적으로 작업을 수행하게 된다. 이러한 과정에서 침입자들에 의한 자원 손실을 막고 정보 무결성을 유지하는 것은 중요한 문제가 된다. 따라서 분산 환경에서는 분산된 자원 사용에 대한 인증(Authentication) 및 인가(Authorization)과정 등의 중요성이 증대되었다. 이질적인 시스템간의 분산 환경을 구축할 수 있는 미들웨어(Middleware)중 가장 활발히 연구되고 이는 CORBA 에서는 보안 서비스를 제공해 주기 위해 COSS (Common Object Service Specification)3에서 보안 서비스를 정의했다. 하지만 COSS3에서 정의한 객체 접근제어 기법만으로는 효율적인 보안 정책 관리가 어렵다. 따라서 본 논문에서는 CORBA 보안 서비스 중 객체 접근제어를 위해 역할-기반 접근제어 (RBAC : Role - Based Access Control)기법을 이용한 효율적이고 융통성 있는 보안정책 관리에 대해 논한다.

• Journal of the Korea Society of Computer and Information
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• v.9 no.3
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• pp.63-69
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• 2004

The purpose of this paper is to design a system model which is needed for integrating the secure role-based access control model into web-based application systems. For this purpose, firstly, the specific system architecture model using a user-pull method is presented. This model can be used as a design paradigm. Secondly, the practical system working model is proposed. which specifies the mechanism that performs role-based access control in the environment of web-based application systems. Finally, the comparison and analysis is shown in which the merits with the proposed system model is presented.