• Proceedings of the Korean Information Science Society Conference
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• 2000.04b
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• pp.705-707
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• 2000

본 논문에서는 교육 실험용으로 사용할 수 있는 실시간 시스템 프로토타입 tool kit을 개발하였다. 하드웨어 부분에서는 8개의 센서 입력 채널과 8개의 제어 신호 출력 채널을 가지는 AT(ISA) 버스용 I/O 보드를 제작했다. 소프트웨어 부분에서는 실시간 운영체제인 VxWorks 상에서, 이 I/O 보드를 제어할 수 있는 디바이스 드라이버를 구현하고, 이를 바탕으로 멀티 스레딩과 우선 순위 스케줄링을 이용한 세차장 모델 제어 프로그램을 제작했다. 또, 현재 부각되고 있는 인터넷을 통한 원격 제어를 실현하기 위해 TCP/IP 기반의 웹서버와 자바 애플릿으로 구현된 원격 제어 클라이언트도 내장시켰다. 그리고 이 tool kit의 효용성을 입증하기 위해 Lego Dacta를 이용하여 세차장모형을 제작하고 본 tool kit에 접속하여 인터넷에서 원격 제어가 가능한 실시간 새차장 시스템의 프로토타입을 구현하여 보았다.

• Journal of Engineering Education Research
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• v.22 no.1
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• pp.55-60
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• 2019

This paper deals with the process and requirements of a capstone design project performed by undergraduate students. We discuss about the preliminary study for the capstone design, the derivation of a subject, the level descriptor of the subject, and the system requirements. And then, we summarize the results of the capstone design project entitled as Microsoft Azure based IoT (Internet of Things) system which is performed by 4 undergraduate students during 10 months. This system is composed of a Zigbee sensor network, the TCP/IP Internet, an IoT server, and a smartphone application program, with which we can gather the sensor data and control actuators at the far away area.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.05a
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• pp.781-784
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• 2008

최근 멀티미디어 콘텐츠가 빠르게 확산되고, 초고속 광대역 IP 네트워크 기술이 발전하면서 통신과 방송의 독자적 개별 서비스가 서로 공존하여 통합융합 서비스로 진화발전하고 있다. 대표적 방송/통신융합 서비스인 IPTV는 통합융합서비스의 가장 강력한 응용분야이며, IPTV와 같은 서비스들이 증가함으로 인해 다양한 인터넷 서비스를 구현하기 위해서 인터넷 프로토콜을 통한 고화질의 데이터 처리에 대한 관심이 통신업계의 화두로 등장하고 있다. 본 연구에서는 소규모에서 사용되는 표준 라우팅 프로토콜인, RIP 환경과 대규모 자율 네트워크에서 사용되는 링크 상태 라우팅 프로토콜인, OSPF 환경을 구현하여 IPTV 서비스 중에서 방송 화질의 PSNR값으로 성능을 측정하고 평가하여 효율적인 IPTV 서비스를 위한 네트워크 구축 방안을 제시하고자 한다.

• Journal of The Korean Association of Information Education
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• v.15 no.1
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• pp.129-136
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• 2011

The aim of this study is to present the handover procedures and the performance comparisons of layered mobility management schemes for wireless mobile Internet. To investigate efficient mobility management schemes providing seamless information services in a mobile environment, this paper provided the detailed discussions of existing network layered mobility management scheme, including Mobile IPv4, Mobile IPv6, and new transport layer mobility management scheme, stream control transmission protocol (SCTP) based mobility architecture (SMA). Network simulator-2 (ns-2) was used to compare the performance between Mobile IPv6 and SMA in the wireless mobile Internet environment. Simulation results show that for typical network configuration and parameters, SMA has a lower handover latency, lower packet loss rate, and higher throughput than Mobile IPv6.

• The Journal of Korean Association of Computer Education
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• v.13 no.5
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• pp.103-110
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• 2010

If an exterior computer wants to join the Grid/cloud computing platform for a while, all of the related firewalls' filtering rule should be immediately updated. As the platform of Internet application is gradually evolving into the Grid/Cloud environment, the R&D requirement for the dynamic traversing of the multiple firewalls by a single try is also increasing. In this paper, we introduce the new mechanism for the dynamic traversing of the multiple firewalls using the concept of the one-time master key that can dynamically unlock the tiers of firewalls simultaneously instead of the existed filtering rule based method like a lock management at each firewall. The proposed master keys are like one-time password, consisted of IP addresses, port numbers, and TCP's initial sequence numbers, and generated by end users not administrators. They're exchanged mutually in advance and used to make a hole at local-side firewalls for the other's packet incoming. Therefore, the proposed mechanism can function regardless of the number or type of firewalls.

• The Journal of Korean Association of Computer Education
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• v.16 no.3
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• pp.99-105
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• 2013

The FPGA-based emulation is an essential step in ASIC design for validation. For emulation with maximal frequency, it is crucial to understand the FPGA characteristics. This paper attempts to analyze the performance characteristics of the modern FPGAs from renowned vendors, Xilinx and Altera, with a case study utilizing various adders and MIPS CPU. Unlike the common wisdom, ripple-carry adder (RCA) does not utilize the inherent carry-chain inside FPGAs when structurally designed based on 1-bit adders. Thus, the RCA shows the inferior performance to the other types of adders in FPGAs. Our study also reveals that FPGAs from Xilinx exhibit different characteristics from the ones from Altera. That is, the prefix adder, which is optimized for speed in ASIC design, shows the poor performance on Xilinx devices, whereas it provides a comparable speed to the IP core on Altera devices. It suggests that error-prone manual change of the original design can be avoided on Altera devices if area is permitted. Experiments with MIPS CPU confirm the arguments.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.404-407
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• 2014

Delay Tolerant Network (DTN) is a networking architecture that is designed to solve network problem in unstable and stressed environments using the Store-Carry-Forward method. Different form general networks, DTN does not guarantee the end-to-end connectivity, it is hard for the exiting TCP/IP based protocols to normally work due to the characteristic such as large latency and unstable link connectivity. And the condition that send massage without the information of the destination occurs frequently. Thus, suitable routing protocols for DTN are required and being researched. In this paper, we propose a novel routing protocol for DTN utilizing epidemic and prediction based algorithm to prevent the defect of previously DTN routing protocols such as the absence of the holistic view of the network. Proposed algorithm predicted destination using the mobility information recorded in neighbor node's history and utilize epidemic based algorithm when occurred condition without destination's information. This algorithm is enhanced in terms of delivery ratio, decreases latency and overhead in sparse network such as DTN.

• Journal for History of Mathematics
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• v.19 no.3
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• pp.1-20
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• 2006

The administrative service in Chosun Dynasty relating to mathematics was carried out by the middle class(中人) mathematicians selected by the official selection examination(取才). They belong to HoJo(戶曹) department and their ranks are GyeSa(計士), ByulJe(別提), HunDo(訓導 = mathematics teacher), and GyoSu(敎授 = mathematics professor). We call them SanWon(算員). HunDo and GyoSu played very important role although their ranks are low, for they educate SanWon and manage the official selection examination. Using JuHakSeonSaengAn(籌學先生案, List of mathematics teachers) and JuHakIpGyukAn(籌學入格案, List of successful candidates in the official selection examination for mathematics), we investigate HunDo and GyoSu in Chosun Dynasty.

• Electronics and Telecommunications Trends
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• v.19 no.3 s.87
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• pp.125-135
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• 2004

차세대 통신망 기술은 개별망에서 단일망인 광대역통합망으로 발전되어 가고 있는 추세이며, 향후 유. 무선 통합 및 방송. 통신 융합이 가능한 IP 기반의 멀티네트워크로 통합될 것이다. 본 고에서는 우리나라가 주도하고 있는 국내, 국제 연구망과 해외 여러 나라들이 추진하고 있는 연구개발망에 대해 살펴보고 첨단 연구개발망을 활용하여 연구개발하고 있는 주요 사항들 즉, IPv6, Measurement, Multicasting, VoIP 같은 네트워킹 기술과 바이오, 나노, 의료, 기상, 교육, 환경 연구 등 과학기술 전반에 걸쳐 6T를 포괄하는 첨단기술을 연구하는 연구개발망에 대한 동향 분석과 IT 분야의 핵심기술과 인프라 제공을 위한 BcN 기반의 연구시험망 구축 방안에 대해 살펴본다. 이러한 첨단 연구개발망은 지속적인 성장과 글로벌시대의 고부가가치 창출을 위한 차세대 연구망으로 미래 선도기술을 배양하는 역할을 수행하는 핵심기술개발과 상용화와 연구개발 기술간의 격차를 줄임으로써 개발기간의 단축과 가격경쟁력을 향상시킬 것으로 사료된다.

• Journal of Convergence for Information Technology
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• v.9 no.6
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• pp.13-18
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• 2019

This paper proposes efficient and secure two-way authentication protocol for binding update messages between mobile devices and home agents / correspondent nodes in IoT and Mobile IPv6 (MIPv6) environments with limited computing power and resources. Based on the MIPv6 message exchange, the proposed protocol satisfies both the authentication and the public key exchange optimized for both sides of the communication with minimum modification. In the future, we will carry out a performance analysis study by implementing the proposed protocol in detail.