• Journal of Information Processing Systems
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• v.17 no.3
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• pp.615-629
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• 2021

With the development of mobile edge computing, how to utilize the computing power of edge computing to effectively and efficiently offload data and to compute offloading is of great research value. This paper studies the computation offloading problem of multi-user and multi-server in mobile edge computing. Firstly, in order to minimize system energy consumption, the problem is modeled by considering the joint optimization of the offloading strategy and the wireless and computing resource allocation in a multi-user and multi-server scenario. Additionally, this paper explores the computation offloading scheme to optimize the overall cost. As the centralized optimization method is an NP problem, the game method is used to achieve effective computation offloading in a distributed manner. The decision problem of distributed computation offloading between the mobile equipment is modeled as a multi-user computation offloading game. There is a Nash equilibrium in this game, and it can be achieved by a limited number of iterations. Then, we propose a distributed computation offloading algorithm, which first calculates offloading weights, and then distributedly iterates by the time slot to update the computation offloading decision. Finally, the algorithm is verified by simulation experiments. Simulation results show that our proposed algorithm can achieve the balance by a limited number of iterations. At the same time, the algorithm outperforms several other advanced computation offloading algorithms in terms of the number of users and overall overheads for beneficial decision-making.

• Journal of the Korean Operations Research and Management Science Society
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• v.4 no.1
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• pp.41-51
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• 1979

The Classical multi-server heterogeneous queuing system can be more generalized by using the concept of the switching rules. The descriptions of these systems, the relations among the state probebilities at the various points of interest, and comparisons with the single-server system will be presented. Instead of using the imbedded markov chain we set up the simultaneous equations for the state probabilites by the supplementary variable method.

• Journal of Broadcast Engineering
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• v.12 no.4
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• pp.342-349
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• 2007

In general multi-view system, all the view sequences acquired at the server are transmitted to the client. However, this kind of system requires high processing power of the server as well as the client, thus it is posing a difficulty in practical applications. To overcome this problem, a relatively simple method is to transmit only two view-sequences requested by the client in order to deliver a stereoscopic video. In this system, effective communication between the server and the client is one of important aspects. Therefore, we propose an efficient multi-view system that transmits two view-sequences according to user's request. The view selection process is integrated into MPEG-21 DIA (Digital Item Adaptation) so that our system is compatible to MPEG-21 multimedia framework. Furthermore, multi-view descriptors related to multi-view camera and systems are newly introduced. The syntax of the descriptions and their elements is represented in XML (extensible Markup Language) schema. Intermediate view reconstruction (IVR) is used to reduce such discomfort with excessive disparity. Furthermore, IVR is useful for smooth transition between two stereoscopic view sequences. Finally, through the implementation of testbed, we can show the valuables and possibilities of our system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.2
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• pp.924-944
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• 2017

Telecare Medical Information System (TMIS) helps the patients to gain the health monitoring information at home and access medical services over the mobile Internet. In 2015, Das et al proposed a secure and robust user AKA scheme for hierarchical multi-medical server environment in TMIS, referred to as DAKA protocol, and claimed that their protocol is against all possible attacks. In this paper, we first analyze and show DAKA protocol is vulnerable to internal attacks, impersonation attacks and stolen smart card attack. Furthermore, DAKA protocol also cannot provide confidentiality. We then propose a lightweight pseudonym AKA protocol for multi-medical server architecture in TMIS (short for PAKA). Our PAKA protocol not only keeps good security features declared by DAKA protocol, but also truly provides patient's anonymity by using pseudonym to protect sensitive information from illegal interception. Besides, our PAKA protocol can realize authentication and key agreement with energy-saving, extremely low computation cost, communication cost and fewer storage resources in smart card, medical servers and physical servers. What's more, the PAKA protocol is proved secure against known possible attacks by using Burrows-Abadi-Needham (BAN) logic. As a result, these features make PAKA protocol is very suitable for computation-limited mobile device.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.3
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• pp.190-198
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• 2013

Since the facilities for the remote users tend to be deployed in distributed manner, authentication schemes for multi-server communication settings, which provide various web services, are required for real-world applications. A typical way to authenticate a remote user relies on password authentication mostly. However, this method is vulnerable to attacks and inconvenient as the system requires users to maintain different identities and corresponding passwords. On the other hand, the user can make use of a single password for all servers, but she may be exposed to variants of malicious attacks. In this paper, we propose an efficient and secure authentication scheme based on a brokered authentication along with smart-cards in multi-server environment. Further we show that our scheme is secure against possible attacks and analyze its performance with respect to communication and computational cost.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.897-900
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• 2011

최근 새로운 소프트웨어 배포 방식인 SaaS가 주목을 받고 있다. SaaS는 원활하고 효율적인 서비스 제공을 위하여 소프트웨어 서비스를 제공하는 SaaS 어플리케이션과 과금, 사용자 인증과 같은 공통 서비스들을 제공하는 SaaS 플랫폼으로 역할이 분리되어 있다. 이런 배경을 바탕으로 본논문에서는 효율적인 사용자인증을 위한 SaaS 플랫폼의 사용자인증 서비스인 Multi-Authentication Server를 설계 한다. 본논문에서 설계되는 Multi-Authentication Server는 OpenID, OAuth, CAS, X.509 프로토콜을 통합하여 웹기반의 사용자인증 서비스를 구현한다. 마지막으로 웹기반 사용자 인증의 보안성 한계 극복과, 최근 하드웨어 보안기능을 이용하여 RADIUS 프로토콜과 TPM칩을 통합한 하드웨어 기반 네트워크 인증서비스를 제공한다.

• Journal of the Korea Society of Computer and Information
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• v.7 no.4
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• pp.33-39
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• 2002

The present so many systems are used by evolution of Program to expel DNC(Direct Numerical Control) Network Infra for many CNC Controller. However, these systems is an inefficiency side in case of mutual connection at a long distance between Server Computer and Machining center Also, the machining center have so many controversial points in data transmission-receiver from the NC data server. So, this thesis well constructed the remote control system from CNC(Computer Numerical Control) Controller to CAD/CAM Server Computer. This system have some kinds of merits. Firstly. the machining center's user can easily use the saved NC data transmission from the CAD/CAM Server Secondly, the remote control is possible without the mutual conversation between the CAD/CAM Server and the machining center.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.4
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• pp.833-838
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• 2014

Recently the use router is to allow multiple computers by one IP can be connect to the Internet. Also, the PC or server in order to use a Web server or a print server, Web Hard, P2P should be settings. In this paper, we are building a multi-functional Web server that using a router supported OpenWRT based on network settings and firewall settings and a variety of services. A web server can be provided the Internet phone and secure multimedia service Web server router based OpenWRT may be provided through a mobile app and the PC application service.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.10
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• pp.60-71
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• 2012

This paper proposes a new design and implementation of multi-protocol IED for networked control system of multi-induction motor in industrial fields. The experimental multi-induction motor based multi-protocol IED of Modbus/LonTalks/TCP/IP module is designed and fabricated. This article addresses issues in architecture of LonWorks/Ethernet sever, embedded processors architecture for converting Modbus protocol to LonTalks protocol, integrating preconfigured software, and Internet technologies. It is also verified that the multi-induction motor control and monitoring system using LonWorks/Ethernet server have available, interoperable, reliable performance characteristics from the experimental results, especially, the seamless integration of TCP/IP networks with control networks allows access to any control point from anywhere. Thus, the results provide available technical data for remote distributed motor control system of industrial field or building microgrid with LonWorks BAS.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.01a
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• pp.69-70
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• 2022

본 논문에서는 Photon Network를 사용하여 경찰과 도둑 컨셉으로 5명이 함께 즐길 수 있는 Multi Game을 구현하였다. 서버는 리슨 서버 방식으로 Master Client가 게임을 시작하면 Game에 참가한 모든 Player는 Photon Network의 RPC 기능을 사용하여 Player의 동작, Game 진행 상황 등을 실시간으로 Server에 동기화한다.