• Journal of the Korea Society of Computer and Information
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• v.8 no.4
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• pp.35-40
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• 2003

In this paper, I raise an issue regarding the relationships between the Election problem and the Consensus problem in asynchronous systems with unreliable failure detectors. First, I describe our system model, and then define Leader Election. After then, I show that the Election problem is harder to resolve than the Consensus problem. Each correct process eventually gets into the state in which it considers only one process to be a leader. Therefore a Perfect Failure Detector is the weakest failure detector which is sufficient to solve the Election. In order to show that the Election problem is harder to resolve than the Consensus problem, I utilize the Reduction protocol in this paper.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.625-630
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• 2006

Zigbee 센서 네트워크에서는 multihop 전송을 위하여 tree topology와 beacon-enabled 네트워크 구성을 갖는다. 이러한 multihop beaconing 네트워크의 목적은 routing 노드들에게 Sleep할 기회를 주어 파워의 소모를 줄이고자 하는 데 있다. 파워의 소모를 줄이고 beacon 전송시의 충돌을 방지하기 위하여 beacon 전송 스케줄링이 필요한데 본 논문은 multihop을 지원하고 에너지 효율에 효과적인 beacon 전송 스케줄링 알고리즘과 이를 바탕으로 에너지 효율적인 라우팅 기법을 제안한다. 본 제안은 Zigbee coordinator의 beacon interval(BI)이 결정되면 네트워크 내의 beacon을 전송하는 모든 노드들은 Zigbee coordinator의 BI를 알고 모든 노드의 superframe duration(SD)은 동일하다고 가정한다. 이러한 가정하에서 beacon을 전송하는 노드들이 Zigbee coordinator의 BI 구간 중 항상 정해진 시간에 자신의 beacon을 전송한다면 beacon의 충돌을 막을 수 있음을 보여 준다. 또한 노드들이 서로의 beacon 전송 시간을 알 수 있기 때문에 목적지 노드의 beacon을 tracking하지 않고도 목적지 노드가 active 되는 시점에 패킷을 전송하면 에너지 측면에서 좀 더 효율적인 라우팅 기반을 제공한다는 것을 보여 준다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.10 s.352
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• pp.35-45
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• 2006

Coordinator is defining so that function as most trust center that is point in security in ZigBee Alliance. Because must do height connection with coordinator in device signing to PAN newly, coordinator has shortcoming that subordinate is revealed to danger directly to Centered and cattish device. When do height connection some device, do not become problem, but if network is huge, coordinator's subordinate shall increase as traffic quantity which happen in coordinator increases. Also, in ZigBee security to link network kina of transmission and mutually certification in ZigBee Alliance standard include, but I do not provide method to deliver master key in each node safely. Because process that transmit master key passes through channel that do not secure, master key has shortcoming that is revealed directly. In this paper, I suggested Parent-Child key establishment algorithm to solve these problem. Proposed algorithm consists of two structures. Master key establishment algorithm and device that sign to PAN newly that can use one-way Hash chain and transmit master key safety are consisted of Parent-Child network key establishment algorithm that do child node and parent node key establishment as can do key establishment efficiently. Method that device proposes in case method that propose in case have master key establishment time was shown better performance $200{\sim}1300ms$ than existing method, and device does not have master key than existing method height connect time about $400{\sim}500ms$ better performance see.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.5
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• pp.335-340
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• 2013

This paper has designed and realized educational ZigBee equipment befitting to the USN environment. In addition, this study has enabled users to exercise operation process for software technology education and to propose software design methods in the process in the USN environment through practice equipment for ZigBee education. As for the development environment of system, Atmega128 process of Atmel is used for CPU; AVR compiler for the debugging environment; C language for firmware development language; and C++ for application program. The system operation process is initiated by coordinator's sensing information reading order from the hyper terminal through a server through the Internet or directly connected; and then delivering it to a terminating device by using ZigBee technology. The terminating device delivers various sensing information to the coordinator which delivers it to a server through the Internet or to a HYPER terminal directly connected to the coordinator. As for the educational course, it is about practices on such ZigBee operation process and relevant programing skills. Regarding it, the communication between coordinator and terminating device is designed by utilizing physical layer of ZigBee protocol, MAC layer and network layer while the communication between server and coordinator is designed by proposing an independent protocol on TCP/IP socket and the protocol processing procedure during sensing data delivery is verified by interpretation.

• Journal of Korean society of Dental Hygiene
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• v.6 no.4
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• pp.437-453
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• 2006

To analyze dental hygienists and other manpower at dental care service institutions where a dental coordinator was working among about 200 dental care service institutions in Seoul, Gyeonggi Province, and Incheon as of June 2005 for contents of training for dental coordinators, opinions of qualification of dental coordinators, present and future services provided by dental coordinators, and awareness of dental coordinators and to provide basic data about future services, roles, and cultivation of dental coordinators, a survey was conducted and 216 copies returned were analyzed, obtaining the following results. 1. 83.8 percent needed an educational program for dental coordinators as an educational content; 41.7% had awareness of the educational content; and 83.8 percent insisted that over the intermediate level of curricula should be taken. Dental coordinator cultivation institutions identified included the institution under the control of the Korean Dental Hygienists Association and the education center for the department of dental hygiene; 76.9% insisted that an appropriate qualifying examination should be necessary. They suggested the central government department and the local government as a certification institution; 39.4% insisted that financial support for the education should be provided by financing education alone. Only 28.7% experienced dental coordinator education and 73.1% hoped to serve as a dental coordinator. They were found to expect a rise in payment(64.4%) and in the title(46.8%) after completion of the educational program. 2. 66.2% saw a dental hygienist as the most appropriate for a dental coordinator; clinical career (39.4%) and practical capacity(29.2%) were suggested as requirements for a dental coordinator; and a period of over three years(47.2%) was suggested for appropriate dental career. 3. Dental coordinators' present services included 'reservation management' for customer management, 'staff service training' for organization management, 'understanding of customer reception attitudes and actions' for self-management, 'hospital information management' for hospital marketing, 'acceptance' for hospital affairs management, and 'hospital environment management' for hospital facilities management; their future services included 'acquisition of ability to use a foreign language' for self-management, followed by 'staff service training' for organization management, 'training and counseling' for customer management, 'acquisition of counseling capacity' for self-management, 'complaining customer reception' for customer management, and 'marketing strategy implementation' for hospital marketing. 4. After comparing dental hygienists and other manpower in terms of dental coordinators' future services, dental hygienists showed interest in 'acquisition of ability to use a foreign language,' 'staff service training,' 'complaining customer reception,' and 'acquisition of counseling capacity' while other manpower showed interest in 'acquisition of ability to use a foreign language,' 'document data management,' 'acquisition of basic service manner,' 'acquisition of counseling capacity,' 'manpower management,' 'establishment and evaluation of a marketing strategy,' and 'education and counseling.' 5. As for awareness of dental coordinators, they were thought of as helpful in improving image of a dental clinic; it was found that continuous training should be necessary to develop dental coordinators' capacity; dental coordinators' services should be important and contribute to patients' qualitative satisfaction.

• RED RIBBON
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• s.35
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• pp.12-13
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• 2000

• Korea Journal of Hospital Management
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• v.18 no.2
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• pp.1-14
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• 2013

• Journal of the Korean Wood Science and Technology
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• v.8 no.3
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• pp.97-103
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• 1980

• Magazine of the Korean Society of Hazard Mitigation
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• v.5 no.3 s.18
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• pp.33-39
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• 2005

• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.867-869
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• 2007

TinyOS기반 무선센서노드를 사용한 실시간 계측 데이터 측정 및 제어기술은 유비쿼터스 센서 네트워크 분야에 주로 사용되어 왔으나 다양한 응용이나 신뢰성 있는 무선 네트워크 연구 개발에 한계가 있는 것으로 알려져 있다. 본 논문에서는 ATMega128L을 장착한 최소 8대 이상의 nano-24 센서 노드모듈과 메모리 용량이 매우 제한적인 무선 센서 노드에 적합하다고 평가받고 있는 Nano-Q+를 사용하여 전시물 주변의 환경 정보를 실시간 측정하는 시스템을 구현하였다. 전시물 주변의 센서들은 하나의 PAN Coordinator를 중심으로 Start-Mesh 네트워크를 구성하여 환경 정보를 측정한다. 환경 정보를 전송 하기 위해 측정된 계측 데이터를 센서 네트워크의 PAN Coordinator 노드로부터 환경 모니터링 서버로 효율적으로 전송하기 위한 TCP기반 전송 프로그램을 구현하였다. 실험 결과 센서 노드 수와 관련된 PAN의 크기 및 샘플링 주기에 상관없이 안정적으로 계측 데이터 수신이 이루어짐을 확인 하였다.