• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2750-2752
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• 2001

각종 행정 업무나 금융 업무 등 많은 분야의 업무를 Network로 처리할 수 있도록 Internet 환경이 구축된 현실에서 개개인의 신상정보 또는 금융정보 등과 같은 누설되어서는 안 되는 다량의 정보들이 Internet을 통해 전송 되어지고 있다. 거미줄처럼 얽혀있는 Internet망을 통한 통신 중 어디 한곳에서라도 정보가 손실된다면 큰 혼란을 가져 올 것이다. 또한 누군가가 Internet망을 통해 전송되는 정보들을 들여다 볼 수 있다면 Encryption되지 않은 Data는 모두 누설되고 말 것이다. 이러한 위험요소들은 기술적으로 구현이 가능하며 실제적으로도 암암리에 행해지고 있는 것으로 알려져 있다. 현재 Internet Security를 위한 많은 Encryption Protocol이 존재하고 있지만 일관된 Encryption Protocol의 부재, 사용의 어려움, Cryptography Application의 부재로 인하여 Encryption을 사용할 수 없는 경우가 많이 있다. 본 논문에는 Eavesdropping의 원리를 이해하고 이에 대한 대책을 제시하였다.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.3 s.96
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• pp.91-102
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• 1999

Fieldbus provides real-time data communication among field devices in the manufacturing automation and process control systems. In this study, an experimental model of fieldbus-based manufacturing automation system is developed. Experimental model consists of two robots, two conveyor belts, NC machine, PLC, sensors and operator station. These machines are interconnected into the Profibus network, and exchange their data through the services provided by FMS(Fieldbus Message Specification), which is the application layer protocol of Profibus. The experimental model is used to measure the network-induced delay of variable and file data transmitted through FMS services. Network-induced delays are collected and analyzed on each sublayer of Profibus protocol stack. The results obtained from the experiment of this study can be effectively utilized when fieldbus is implemented on the practical manufacturing automation systems.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.569-571
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• 2015

본 논문에서는 IoT(Internet of Things) 표준 프로토콜인 IETF(Internet Engineering Task Force) CoAP(Constrained Application Protocol)을 이용한 실내 자원 제어 구조를 제시한다. 제안한 웹 기반 실내 환경 제어 구조에서는 웹 서버에 프록시(proxy)와 자원 디렉토리(RD : Resource Directory) 기능을 포함하고 있다. 이를 통해 CoAP 프로토콜을 통해 저전력, 소규모의 노드를 웹 서버에 등록하고, 프록시의 HTTP과 CoAP 메시지 변환 기능을 이용하여 사용자가 웹브라우즈를 이용하여 실내 환경을 제어할 수 있다.

• Journal of Information Processing Systems
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• v.10 no.2
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• pp.300-313
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• 2014

Various Time Synchronization protocols for a Wireless Sensor Network (WSN) have been developed since time synchronization is important in many time-critical WSN applications. Aside from synchronization accuracy, energy constraint should also be considered seriously for time synchronization protocols in WSNs, which typically have limited power environments. This paper performs analysis of prominent WSN time synchronization protocols in terms of power consumption and test by simulation. In the analysis and simulation tests, each protocol shows different performance in terms of power consumption. This result is helpful in choosing or developing an appropriate time synchronization protocol that meets the requirements of synchronization accuracy and power consumption (or network lifetime) for a specific WSN application.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.566-568
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• 2015

최근 IETF(Internet Engineering Task Force) CoRE(Constrained RESTful Environment) 워킹그룹에서 IoT 프로토콜로 CoAP(Constrained Application Protocol)을 표준으로 채택하였다. 본 논문에서는 모바일 환경에서 CoAP 프로토콜을 이용한 자원 디렉토리 기반의 IoT 노드와 스마트폰 연결 구조를 제시한다. 스마트폰과 IoT(Internet of Things) 노드 사이에 자원 디렉토리를 두고, 이를 통해 스마트폰은 IoT 노드를 검색하고 상황 정보를 습득할 수 있도록 하고 있다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.6
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• pp.195-199
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• 2009

This paper defines a new variation of CDH problem where an adversary interacts with a challenger and proves its security is equivalent to the CDH problem. This new problem is useful in designing a cryptographic protocol. To show the versatility of this problem, we present a new identification scheme. Finally, we show a decisional version of this protocol.

• International journal of advanced smart convergence
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• v.12 no.1
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• pp.9-17
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• 2023

Recently, IoT technology has been widely used in many industries. Also research on integrating IoT technology with IoT sensors is actively underway. One of the important challenges in IoT is to support low-latency communication. With the development of communication networks and protocols, a variety of protocols are being used, and their performance is improving. In this paper, we compare the performance and analyze the characteristics of some of the major communication protocols in IoT application, namely MQTT, HTTP, and HTTPS. IoT sensors acquired data by connecting an Arduino equipped with ESP8266 and a temperature and humidity sensor (DHT11). The server measured the performance by building servers for each protocol using AWS EC2. We analyzed the packets transmitted between the Arduino and the server during the data transmission. We measured the amount of data and transfer time. The measurement results showed that MQTT had the lowest data transmission time and data amount among the three protocols.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.6
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• pp.324-333
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• 2004

This paper discusses the development of an educational web-based power flow program for undergraduate students. The interaction between lectures and users can be much enhanced via the web-based programs which result in the student's learning effectiveness on the power flow problem. However the difficulties for developing web-based application programs are that there can be the numerous unspecified users to access the application programs. To overcome the aforementioned multi-users problem and to develope the educational web-based power flow program, we have revised the system architecture, the modeling of application programs, and database which efficiently and effectively manages the complex data sets related to the power flow analysis program. The developed application program is composed of the physical three tiers where the middle tier is logically divided into two kinds of application programs. The divided application programs are interconnected by using the Web-service based on XML (Extended Markup Technology) and HTTP (Hyper Text Transfer Protocol) which make it possible the distributed computing technology Also, this paper describes the method of database modeling to handle effectively when the numerous users change the parameters of the power system to compare the results of the base case.

• Proceedings of the KIEE Conference
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• 2004.11b
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• pp.94-96
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• 2004

This paper discusses the development of the educational simulator for the electricity spot market in korea. The interaction between lectures and users can be much enhanced via the web-based programs which result in the student's teaming effectiveness on an electricity spot market. However the difficulties for developing web-based application programs are that there can be the numerous unspecified users to access the application programs. To overcome the aforementioned multi-users problem and to develope the educational simulator, we have revised the system architecture, the modeling of application programs, and database which efficiently and effectively manages the complex data sets related to an electricity spot market. The developed application program is composed of the physical three tiers where the middle tier is logically divided into two kinds of application programs. The divided application programs are interconnected by using the Web-service based on XML (Extended Markup Technology) and HTTP (Hyper Text Transfer Protocol) which make it possible the distributed computing technology.

• Journal of Korea Multimedia Society
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• v.17 no.5
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• pp.640-653
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• 2014

Recently medical consumers pursue high leveled quality of life through active promotion, prevention, management activity of health as the importance of health during home life is emerged to meet the aging society and chronic diseases. In addition, people are directed to the m-Health for managing yourself their health by using smartphone and various personal health devices, if necessary transmits health data to the physician himself. In the previous studies, m-Health Application were developed and applied in the real clinical environment by adopting the medical information standards was rarely conducted. Therefore, in this study, the m-Health application platform was developed. Developed application was communicate with IEEE 11073 standard protocol using the Bluetooth Health Device Profile in personal health device via smart phone to process blood pressure information, and it converted to HL7 V2.6 ORU_R01 message for send to remote medical server. In addition, we tested the interoperability and safety of the developed application for 23 inpatient and 17 outpatient at D University Hospital. As a result, the blood pressure information has been transmitted without error.