• Journal of KIISE:Computing Practices and Letters
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• v.10 no.3
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• pp.231-242
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• 2004

Remote control and monitoring of information appliances require RTOS and TCP/IP network module to communicate each other. Traditional TCP/IP protocol stacks, however, require relatively large resources to be useful in small 8 or 16-bit systems both in terms of code size and memory usage. It motivates design and implementation of micro TCP/IP that is lightweight for embedded systems. Micro embedded web server is also required to control and monitor information appliances through the Web. In this paper, we design and implement micro TCP/IP and Web server for information appliances. For this goal, we investigate requirements for the interoperability of embedded systems with the Internet and the Web-based control of embedded systems. Next, we compare our micro TCP/IP protocol stack with that of RTIP and QPlus in terms of object code size and performance. The size of micro TCP/IP protocol stack can be reduced by 3/2 and 1/4, respectively, comparing with that of RTIP and QPlus. We also show that the performance of our micro TCP/IP is similar to that of RTIP and QPlus since it handles 2.9Mbps when delayed ACK is not adapted.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.5
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• pp.19-28
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• 2012

Recently a grid and cloud computing collaboration have become a social issue. These collaborative network system, the P2P system based on this system. Distingui shed from the client/server systems, P2P systems in order to exchange information, its purpose and functions are divided according to the morphological Category. In accordance with the purposes and functions of information and data retrieval, remote program control and integration services for the offers. Most P2P systems client/server scalability, and management takes the form, but to overcome the disadvantages in terms of applying the mixed-mode system is increasing. And recently the distributed computing aspects of the service to users in order to provide suitable to accommodate the diverse needs of various types of mobile agent technology is needed. In this paper, as required by the mobile agent access to a remote resource access control and agent for the execution and management capabilities and improve the reliability of the mobile agent system designed to suggest.

• Information and Communications Magazine
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• v.29 no.12
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• pp.55-61
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• 2012

최근 통신 기술 및 IT기술을 발전이 급속히 이루어지면서 산업 및 사회 전반에 통신을 빼놓고는 일상 생활을 논할 수 없는 환경이 되었다. 특히 수만은 종류의 모바일 단말들이 널리 보급되면서 언제 어디서나 정보를 접근하고 획득할 수 있는 환경이 구축되어 있으며, 실시간 정보를 들을 접할 수 있는 환경이 조성되었다. 특히 통신 관련 장치가 소형화되고 저전력 기술이 적용되면서, 전에는 접할 수 없었던 특정 사물(컴퓨터, 프린터, 가전, 액츄에이터, 동영상 등)에 대한 네트워크적인 접근이 가능하며, 심지어 각종 센서 정보를 원격을 점검할 수 있게 되었다. 이러한 변화는 실 세계의 사물을 응용 단의 하나의 자원으로 활용할 수 있는 환경이 조성되었으며, 특히 웹 기술을 이용해서 자원을 검색하고 접속/제어하려는 작업이 즉, Web of Things(WoT)개발이 이루어지고 있다. 본 논문에서는 WoT에 대한 개념 및 기술적이슈/표준화적 이슈에 대해서 논한다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.814-816
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• 2004

WebDAV(Web-based Distributed Authoring and Versioning)는 웹상의 공동 저작활동을 지원하기 위한 IETF 표준으로서, 멀리 떨어져 있는 사용자들 간에 인터넷상에서 파일을 공동 편집하고 관리할 수 있도록 해주는 일련의 HTTP 확장이다. 이것은 웹 상에서 가상의 작업공간을 구성함으로써, 원격 그룹들 간에 새로운 방식으로 공동작업을 가능하게 한다. WebDAV 클라이언트는 이러한 명세를 지원하는 WebDAV 서버와 HTTP 요청을 통하여 서버 자원에 대한 변경 및 수정 작업을 수행하게 된다. 따라서 클라이언트는 뛰어난 동시성 제어와 속성 관리를 통하여 자원의 저작과 버전관리의 기능을 제공하는 것이 바람직하다. 본 논문에서는 기존의 몇 가지 WebDAV 클라이언트를 분석하여 리눅스 기반의 오픈소스 WebDAV 클라이언트를 설계하였다. 이것은 사용자의 수작업에 의한 문서 저작 절차를 단순화하고 저작 응용프로그램의 모니터링을 통하여 문서 변경에 대한 능동적인 서버 갱신을 지원하도록 설계하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.201-202
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• 2013

최근 기업들의 업무환경이 강력한 이동성을 가지는 모바일 환경으로 일부 이동함에 따라 적은 전력 소모량을 만으로도 기업 업무를 처리할 수 있을 만한 성능의 컴퓨팅 자원을 지원 가능토록 하는 Thin Client 모델이 주목을 받게 되었다. 또한 이는 사용자 별 독립 자원을 제공할 수 있는 클라우드 기술과 융합하여 단일 모바일 단말과 단일 가상 머신 간의 원격제어를 관리하는 모바일 클라우드라는 개념으로 발전되었다. 그러나 해당 방법으로 얻을 수 있는 작업 처리의 성능은 제공되는 가상 머신의 성능만큼의 제한이 있다. 또한 이종 클라우드 환경을 이용할 시 자원 간 이질성으로 인해 성능의 편차가 발생하기 때문에 이러한 문제를 해결하기 위한 기술이 필요하게 된다. 따라서 본 논문에서는 이러한 모바일 단말에서 이종 클라우드 자원을 이용하여 고성능 컴퓨팅 처리를 가능하도록 하는 위한 모바일 클라우드 환경에서의 고려사항 및 구조를 제안한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.3
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• pp.532-539
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• 2007

Photovoltaic power generation system is one of new renewable energy sources. Such distributed power generation system has important issues for the system management ad operating after its installation. To solve the problem, remote monitoring and control systems can be employed. In this paper, LabVBEW based monitoring and control system is proposed for efficient management and operation of the photovoltaic power generation system. Interface method between monitoring part and DSP controller is given in detail. The proposed system is verified through experiments using a grid-connected photovoltaic power generation system.

• The Journal of Korean Association of Computer Education
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• v.3 no.1
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• pp.127-134
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• 2000

Distance education, which emerged under the influence of both the rapid development of hi-tech information technology and the constructivism theory of learning, enables learners to acquire knowledge and skills needed by monitoring their learning process for themselves. Emphasis on web-based distance education and contructivism as a basis of learner-centered education does not mean that those education systems are performed without teachers or in noninterference. This study proposes a model of distance education system in which learners are taught in various levels of learning with the help of teacher agents. In the model teacher agents produce the learners' respective learning model considering the information on individual learners and also control the progress to the next step of learning with the result of the evaluation of learning accomplishment. The model of distance education system suggested in this study is able to help solve the problem that the learning resources web-based distance education provides were used only as objects of web search and to supply a basis of realizing learner-centered education.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.43 no.4 s.310
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• pp.60-66
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• 2006

Underwater ultrasonic communication is critical to explore and development ocean using instrument. Essential to these applications is the reliable teleoperation and telemetering of the unit. But the problem is that the controllability of the instrument and the reliability of submarine communication are decreased, as so various passive noises are generated. In the existing methods, the control informations, received from an observation instrument, are identified used by hardware and repeatedly compared with standard information. However, such a method weakens the efficiency in controllability-centered systems. This study presents an ultrasonic signal detection algorithm that can identify the ultrasonic signal without the influence of disturbances due to underwater environmental changes. Likewise, the logicality of detection algorithm were ascertained by simulation.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.3
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• pp.579-588
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• 2019

Industrial control systems consist of various physical devices such as sensors, actuators. Security Infringement such as waterworks facilities Remote Access Infringement and power control systems Infection have been occured by vulnerability of Access Control. Access control to physical devices must be fulfilled with a reliable system. However, Having a single access control system inside company can not guarantee reliability. In addition, when single access control is struggled with error or infringement, access control system is totally unavailable. so system requires a additional access control method or system. In this paper, we proposed access control mechanism for reliable and stable operation using blockchain and smart contract. Proposed Mechanism using trust score to consider resources to be consumed depending on each industrial environment in consideration of the industrial control system where availability is more important than integrity and confidentiality. Unlike other blockchain-based access control system, proposed system is designed for the currently operating industrial control system.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.4
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• pp.399-403
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• 2013

Mining diggers have been substituted with the robots for the mining works in dangerous and narrow tunnel, and those demands are increased in nowadays. In this study, experimental research on the remote controlled robots to perform after the development of the robot. According to the test results, performances of the developed robot and its working devices have been modified several times. It has been considered that the robot keeps its optimum performance in states as follows; driving speed 1.0 km/h, crawl angle $10^{\circ}$, spiking cycle 500bpm and breaking power $30kg_fm$. And also it has been found that sufficient cooling for the robot's working parts is essential to extend those working periods longer than 3 hours steadily under rating condition.