• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권2호
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• pp.811-829
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• 2015

One-way authenticated key agreement protocols, aiming at solving the problems to establish secure communications over public insecure networks, can achieve one-way authentication of communicating entities for giving a specific user strong anonymity and confidentiality of transmitted data. Public Key Infrastructure can design one-way authenticated key agreement protocols, but it will consume a large amount of computation. Because one-way authenticated key agreement protocols mainly concern on authentication and key agreement, we adopt multi-server architecture to realize these goals. About multi-server architecture, which allow the user to register at the registration center (RC) once and can access all the permitted services provided by the eligible servers. The combination of above-mentioned ideas can lead to a high-practical scheme in the universal client/server architecture. Based on these motivations, the paper firstly proposed a new one-way authenticated key agreement scheme based on multi-server architecture. Compared with the related literatures recently, our proposed scheme can not only own high efficiency and unique functionality, but is also robust to various attacks and achieves perfect forward secrecy. Finally, we give the security proof and the efficiency analysis of our proposed scheme.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권1호
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• pp.119-131
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• 2013

With the explosive growth of computer networks, many remote service providing servers and multi-server network architecture are provided and it is extremely inconvenient for users to remember numerous different identities and passwords. Therefore, it is important to provide a mechanism for a remote user to use single identity and password to access multi-server network architecture without repetitive registration and various multi-server authentication schemes have been proposed in recent years. Recently, Tsaur et al. proposed an efficient and secure smart card based user authentication and key agreement scheme for multi-server environments. They claimed that their scheme satisfies all of the requirements needed for achieving secure password authentication in multi-server environments and gives the formal proof on the execution of the proposed authenticated key agreement scheme. However, we find that Tsaur et al.'s scheme is still vulnerable to impersonation attack and many logged-in users' attack. We propose an extended scheme that not only removes the aforementioned weaknesses on their scheme but also achieves user anonymity for hiding login user's real identity. Compared with other previous related schemes, our proposed scheme keeps the efficiency and security and is more suitable for the practical applications.

• 정보처리학회논문지B
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• 제12B권4호
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• pp.459-464
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• 2005

온라인 게임 시스템은 크게 서버와 클라이언트 두 부분으로 나누어 볼 수 있다. 클라이언트는 게임 서버와의 접속 그리고 서버로부터 전송되는 패킷 분석 등의 역할을 하며, 게임 서버는 사용자 정보와 데이터베이스 둥의 관리를 수행한다. 특히 게임 서버는 새로운 클라이언트가 게임을 수행하기 위해 서버로의 접속을 허용할 경우 기존에 연결된 사용자와의 온라인 연결을 유지하면서 새로운 클라이언트의 접속 요청을 받아들여 야 한다. 본 논문에서는 서버의 다중 작업 처리를 위한 방법 중 프로세스(Process) 방법과 쓰레드(Thread) 방법의 처리 형태를 비교한 후, 현재 대부분의 게임 서버에 적용되어 있는 비대칭 분산형 구조에 적합한 비대칭 분산형 다중 서버 구조를 제안하였다. 제안한 비대칭 분산형 다중 서버 구조는 서버의 기능을 로그인 서버, 게임 서버, 통신 서버, 데이터베이스 서버 형태로 세부적으로 분리하여 각각의 기능을 독립적으로 수행한다. 따라서 다른 구조들과 비교하였을 경우 경제적, 기능적으로 더 나은 성능을 보이며 특히 서버의 안정성과 확장성이 향상되었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권7호
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• pp.3371-3396
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• 2016

Authentication protocols for multi-server architectures have gained momentum in recent times due to advancements in computing technologies and associated constraints. Lu et al. recently proposed a biometrics and smartcards-based authentication scheme for multi-server environment. The careful analysis of this paper demonstrates Lu et al.'s protocol is susceptible to user impersonation attacks and comprises insufficient data. In addition, this paper proposes an improved authentication with key-agreement protocol for multi-server architecture based on biometrics and smartcards. The formal security of the proposed protocol is verified using the widely accepted AVISPA (Automated Validation of Internet Security Protocols and Applications) tool to ensure that our protocol can withstand active and passive attacks. The formal and informal security analysis, and performance analysis sections determines that our protocol is robust and efficient compared to Lu et al.'s protocol and existing similar protocols.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권3호
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• pp.911-931
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• 2021

Recently, most cloud services use Docker container environment to provide their services. However, there are no researches to evaluate the performance of communication libraries for multi-GPU based distributed deep learning in a Docker container environment. In this paper, we propose an efficient communication architecture for multi-GPU based deep learning in a Docker container environment by evaluating the performances of various communication libraries. We compare the performances of the parameter server architecture and the All-reduce architecture, which are typical distributed deep learning architectures. Further, we analyze the performances of two separate multi-GPU resource allocation policies - allocating a single GPU to each Docker container and allocating multiple GPUs to each Docker container. We also experiment with the scalability of collective communication by increasing the number of GPUs from one to four. Through experiments, we compare OpenMPI and MPICH, which are representative open source MPI libraries, and NCCL, which is NVIDIA's collective communication library for the multi-GPU setting. In the parameter server architecture, we show that using CUDA-aware OpenMPI with multi-GPU per Docker container environment reduces communication latency by up to 75%. Also, we show that using NCCL in All-reduce architecture reduces communication latency by up to 93% compared to other libraries.

• 조명전기설비학회논문지
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• 제26권10호
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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.

• 한국정보통신학회논문지
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• 제12권10호
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• pp.1866-1874
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• 2008

기존의 웹 서버는 과부하 상태인 경우 폐쇄 연결, 암호 핸드쉐이크 실행 증가와 서버 용량의 현저한 감소로 서버의 처리량에 문제가 발생하여 시스템의 전체적인 성능을 저하시킨다. 또한 쓰레드 블록으로 인하여 다수의 클라이언트 요청 처리가 원활하지 못하고, 쓰레드 활성화를 위하여 많은 시간과 자원을 요구하여, 클라이언트의 요청에 대해 접속시간과 응답 시간이 증가하는 단점이 발생한다. 그러므로 본 논문에서는 웹서버스의 장점인 통합과 커뮤니케이션 지원과 시스템 성능 향상을 위해 서버 과부하를 개선하고, 지연처리를 위해 필요한 기술을 제공하는 확장된 웹서버를 제안한다. 그리고 기존 시스템(Tomcat 5.5에서 구현)과 제안한 모바일 웹 서버 아키텍처를 평가한다. 확장된 서버 아키텍처는 시스템 성능을 위해 우수한 교환 조건을 제공하고, 다중쓰레드와 쓰레드풀을 결합한 개선된 웹 서버 아키텍처를 평가한다. 본 논문에서 제안된 웹서비스 아키텍처는 오리지널 Tomcat 5.5의 평가 결과보다 개선된 성능 이익의 결과를 얻었다.

• Journal of information and communication convergence engineering
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• 제7권3호
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• pp.340-344
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• 2009

Multi-server password authentication schemes enable remote users to obtain service from multiple servers with single password without separately registering to each server. In 2007, Hu-Niu-Yang proposed an improved efficient password authenticated key agreement scheme for multi-server architecture based on Chang-Lee's scheme proposed in 2004. This scheme is claimed to be more efficient and is able to overcome a few existing deficiencies in Chang-Lee's scheme. However, we find false claim of forward secrecy property and some potential threats such as offline dictionary attack, key-compromise attack, and poor reparability in their scheme. In this paper, we will discuss these issues in depth.

• 한국지능정보시스템학회:학술대회논문집
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• 한국지능정보시스템학회 2001년도 The Pacific Aisan Confrence On Intelligent Systems 2001
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• pp.511-515
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• 2001

Many intelligent agent systems are known to incorporate BDI architecture for cognitive reasoning. Since this architecture contains all the knowledge of world model and reasoning rule, it is very complex and difficult to handle. This paper describes a methodology to design and implement BDI architecture, BDIAXml based on XML for multi-agent systems. This XML-based BDI architecture is smaller than any other BDI architecture because it separates knowledge for reasoning from domain knowledge and enables knowledge sharing using XML technology. Knowledge for BDI mental state and reasoning is composed of specific XML files and these XML files are stored into a specific knowledge server. Most systems using BDIAxml architecture can access knowledge from this server. We apply this BDIAXml system to domain of Hospital Information System and show that this architecture performs more efficiently than other BDI architecture system in terms of knowledge sharing, system size, and ease of use.

• 한국국방경영분석학회지
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• 제23권2호
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• pp.25-44
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• 1997

Internet users been rapidly increased due to the convenient GUI environment. Current Web-based HTTP/CGI client/server architecture has several problems such as the CGI bottleneck, no maintaince of state, and no load balancing. However, with Java and CORBA technologies called“Object Web technology”, we can solve them because Java is not only a mobile code but also a platform-independent code, and CORBA has ability to build distributed object and language-independent object model. The goal of “Object Web technology”is to create multivendor, multiOS, multilanguage“legoware”using objects. This paper implement“Book Search System”which is Web-based client/server architecture using distributed objects. Environments of this implementation are Hangul Windows NT(included IIS) server, Hangul Windows 95 client, Visigenic's VisiBroker for Java 1.2 which is a product of CORBA 2.0, HTTP protocol on TCP-IP-based, Sybase SQL Anywhere 5.0 database server, and the interface between application server and database is JDBC-ODBC bridge middleware.