• Journal of the Korea Institute of Information and Communication Engineering
• /
• 제18권8호
• /
• pp.1955-1960
• /
• 2014

Many routing protocols have been proposed for low-power and ad-hoc networks to deliver command or data among nodes and recently, various researches are carried out about networking scheme considering reliability and scalability. In low-power networking technology, the performance of network layer is closely connected with the operation of data link layer and mesh routing mechanisms based on TDMA MAC are considered for reliability and scalability. This paper proposes mesh routing algorithm utilizing the characteristics of TDMA MAC and topological addressing in TDMA based low-power and ad-hoc networks and implementation results are presented.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• 제17권5호
• /
• pp.1168-1173
• /
• 2013

This paper proposes a new visualization method based on cloud technique which uses internal relationship of user correlation and external relation of social network to visualize user relationship hierarchy. The visualization method of this paper can well represent user-focused relationship hierarchy on social networks by a correlation matrix. The importance of a access node reflects into user relationship hierarchy by exploiting external relation of social network. Users of the method can well understand user relationships on account of representing user relationship hierarchy from social networks. In addition, the method use hadoop and hive for distribution storing and parallel processing which the result of calculation visualizes hierarchy graph using D3.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 한국정보통신학회 2017년도 추계학술대회
• /
• pp.485-487
• /
• 2017

The whirlpool hash function adopted as an ISO / IEC standard 10118-3 by the international standardization organization is an algorithm that provides message integrity based on an SPN (Substitution Permutation Network) structure similar to AES block cipher. In this paper, we describe the hardware implementation of the Whirlpool hash function. The round block is designed with a 64-bit data path and encryption is performed over 10 rounds. To minimize area, key expansion and encryption algorithms use the same hardware. The Whirlpool hash function was modeled using Verilog HDL, and simulation was performed with ModelSim to verify normal operation.

• Journal of KIISE:Computer Systems and Theory
• /
• 제26권4호
• /
• pp.472-487
• /
• 1999

본 논문에서는 효율적인 이동성 관리를 위한 이동성 예측 기법을 소개한다. 이동 컴퓨팅 환경에서는 사용자가 지리적 위치의 제약없이 언제, 어디서나 다른 네트워크 시스템과 메시지를 주고 받을수 있다. 그러나, 통신자원의 부족, 잦은 접속단절 , 사용자의 움직임 등과같은 이동 컴퓨팅 시스템의 특징 때문에, 지능적이고 효율적인 이동성관리가 요구된다. 이동 컴퓨팅 시스템이 지능적이고 효율적인 이동성관리를 통하여 높은 질의 서비스를 제공하기 위해서는 이동 사용자의 움직임 패턴들을 능동적으로 고려하는 것이 바람직하다. 본 논문에서는 이동 사용자의 과거수일, 수개월동안의 움직임 패턴 즉, 이동사용자의 위치연혁으로부터 미래 위치를 예측하는 지능적 이동성 예측기법(intelligent mobility prediction scheme)을 제안한다. 모델링 방법으로서 뉴로-퍼지 추론시스템(neuro-fuzzy inference system)을 이용한다. 뉴로-퍼지 추론 시스템이 이동 사용자가 움직이게 되는 미래 위치를 예측하기 때문에 , 본 논문에서의 이동성 예측 기법은 통신채널의 사전 배당, 부족한 자원의 사전 할당등을 위해서 사용될 수 있다. 게다가, 본 논문의 시뮬레이션 결과는 제안하는 기법이 다양한 이동 환경에 대해서 높은 예측 정확도를 갖음을 보여준다.

• Journal of KIISE:Computer Systems and Theory
• /
• 제30권7_8호
• /
• pp.331-340
• /
• 2003

Low-cost commodity SMP(Symmetric Multiprocessor) is widely used as a node of cluster system. In this paper, we implement and evaluate the performance of SDSM system for SMP clusters. Our SDSM system provides HLRC(Home-based Lazy Release Consistency) memory consistency model. Our protocol utilize shared memory within same SMP node, so that page fetch and message passing through network can be reduced. It is implemented on 8 node of 2-way Pentium-III SMP interconnected with 100Mbps Fast Ethernet, and uses TCP/IP for transport/network layer protocol. The experiment with eight applications shows that our SMP protocol achieves maximum 33% speedup improvement and 13%-52% reduction of page fetch compared with uniprocessor protocol.

• KIISE Transactions on Computing Practices
• /
• 제22권5호
• /
• pp.235-239
• /
• 2016

'Commit-bug link', the link between commit history and bug reports, is used for software maintenance and defect prediction in bug tracking systems. Previous studies have shown that the links are automatically detected based on text similarity, time interval, and keyword. Existing approaches depend on the quality of commit history and could thus miss several links. In this paper, we proposed a technique to link commit and bug report using not only messages of commit history, but also the similarity of files in the commit history coupled with bug reports. The experimental results demonstrated the applicability of the suggested approach.

• KIISE Transactions on Computing Practices
• /
• 제22권8호
• /
• pp.345-350
• /
• 2016

Cloud computing services have different characteristics from the traditional computing environment such as resource sharing, virtualization, etc. These characteristics of cloud computing environment necessitate specific properties such as user identify, access control, security control property, etc. Recently, Yoo proposed an attribute-based authentication scheme for secure cloud computing. However, Yoo's authentication scheme is vulnerable to customer attack and an adversary can modify the authentication request message. In this paper, we propose a secure and efficient attribute-based authentication scheme for cloud computing based on Yoo's scheme.

• Proceedings of the Korean Information Science Society Conference
• /
• 한국정보과학회 2010년도 한국컴퓨터종합학술대회논문집 Vol.37 No.1(B)
• /
• pp.126-131
• /
• 2010

IT 자원의 상호운용성 및 재활용성 등의 장점 통하여 새로운 비즈니스 환경변화에 가장 빠르게 대응할 수 있는 최적의 대안으로 서비스 지향 아키텍처(SOA : Service Oriented Architecture)가 최근 각광받고 있다. 그러나 구현의 복잡성 및 그에 따른 낮은 ROI(Return on Investment) 평가와 같은 SOA의 문제점들을 보완하기 위해 웹 지향 아키텍처(WOA: Web Oriented Architecture)가 제안되었다. 하지만 WOA 또한 보안 및 안정적인 메시지 전달 등의 문제점들을 안고 있다. 본 논문에서는 SOA와 WOA 구현의 핵심 개념을 연구하고, SOA 또는 WOA를 이용하여 서비스를 구현할 경우 중요한 핵심 개념의 복잡도를 AHP(Analytic Hierarchy Process) 기법을 통하여 평가하였다. 이를 통하여 SOA 또는 WOA 구현 시 요구되는 핵심 요구사항의 중요도를 평가하고 개발자에게 미치는 구현 복잡도를 측정할 수 있다.

• The KIPS Transactions:PartC
• /
• 제15C권1호
• /
• pp.51-60
• /
• 2008

Micro-mobility protocols have been developed to reduce the control message overhead due to movements of mobile nodes. With the spread of mobile devices, services using mobile nodes are increasing and multicast services are becoming more important in providing multimedia services. In this paper we propose a new multicast protocol suitable for micro-mobility environments. The proposed protocol is designed to maintain optimal multicast routing paths and continue to provide multicast services without disruption in spite of frequent handoffs due to movements of mobile nodes. We used simulation to evaluate the proposed protocol, compared its performance with existing multicast protocols for mobile environments including bi-directional tunneling, remote subscription, and MMA, and observed that the proposed protocol exhibited better performance in terms of transmission success ratio and overhead on the network.

• The KIPS Transactions:PartD
• /
• 제15D권5호
• /
• pp.699-704
• /
• 2008

By the dependence on Web from popularization of internet and increasing number of users, web services capability and security problem of communication is becoming a great issue. Existing web services technology decrease the capability of web application server by limiting the number of synchronous client, decreasing the processing load and increasing average response time. The encryption process to secure communication and the early expense of handshake decrease transmission speed and server capability by increasing the calculation time for connecting. Accordingly, this paper executes an encryption procedure by elliptical encryption algorithm to satisfy secure demands, improve the overload of server for web services and get reliability and security of web server architecture and proposes an improved mobile web sever which provides better ability and the techniques for deferred processing.