• Title/Summary/Keyword: 과학 동기

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A Method of the Grandmaster Selection and the Time Synchronization Using Single TimeSync Frame for Audio/Video Bridging (동기식 이더넷에서 단일 타임싱크 프레임을 이용한 그랜드마스터 결정 및 시간 동기 방법)

  • Kang, Sung-Hwan;Lee, Jung-Won;Kim, Min-Jun;Eom, Jong-Hoon;Kwon, Yong-Sik;Kim, Sung-Ho
    • Journal of KIISE:Information Networking
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    • v.35 no.2
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    • pp.112-119
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    • 2008
  • Today, A matter of concern of home network technology increase. The standard of communication between home network devices are required. IEEE 802.1 AVB(Audio/Video Bridging) specifies transmission method for time-sensitive data between these devices using Ethernet in bridged local area networks. IEEE 802.1 AVB and IEEE 1588 PTP(Precision Time Protocol) have various message type for grandmaster selection and synchronize the devices. These messages bring on complexity protocol. We propose a method that uses Single TimeSync frame in order to the problem. Our proposal is appropriate process complexity and low transmission delay for home network by using the TimeSync frame. Furthermore, after all devices are adjusted to the single TimeSync frame, a resource reservation, a forwarding and queueing rule are needed for a time-sensitive application.

Development of Data Synchronization Client based on SyncML (SyncML 기반의 자료 동기화 클라이언트 개발)

  • Jang, Dae-Jin;Park, Kee-Hyun;Ju, Hong-Taek
    • Journal of KIISE:Computing Practices and Letters
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    • v.11 no.4
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    • pp.357-367
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    • 2005
  • According to the recent advancement of mobile computing technology and the hardware technology, the mobile device has rapidly come into wide use.'rho data in the central management server needs to confirm to that in mobile devices in order for the mobile device users to access the needed data regardless of time and place. This is called Data Synchronization. Currently, major mobile device manufacturing companies provide the data synchronization solutions, but these solutions are not compatible with other mobile devices/other applied services. In order to solve this problem, OMA(Open Mobile Alliance), mainly composed of mobile telecommunication companies, has suggested using the SyncML(Synchronization Markup Language) data synchronization method. This is an attempt to make a public standard. In this paper, the data synchronization client that synchronizes the PIMS (Personal Information Management System) data in mobile devices like PDA is developed, complying with the SyncML standard requirements.

An Analysis of Multi-dimension of Students' Interest in Learning Physics (중학생의 물리학습에 대한 흥미의 다차원성 분석)

  • Im, Sung-Min;Pak, Sung-Jae
    • Journal of The Korean Association For Science Education
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    • v.20 no.4
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    • pp.491-504
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    • 2000
  • Recent research has shown that students' interest in learning physics is not a simple one. In this study the dimensions of students' interest in learning physics have been identified. These are the topic being taught, the activity in which the students are involved, and the motive of the students for learning physics. A Likert-style pilot questionnaire was constructed for identifying these dimensions and given to 13 year-old 162 students. A factor analysis of the results indicates that there are meaningful sub-dimensions in interest. In other words, while there were no specific sub-dimensions in topic dimension, motive dimension could be divided into intrinsic motive and extrinsic motive, and activity dimension could also be divided into receptive, experiential, high cognitive, and interactive activity.

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Proof that the Election Problem belongs to NF-completeness Problems in Asynchronous Distributed Systems (비동기적 분산 시스템에서 선출 문제는 NF-completeness 문제임을 증명)

  • Park, Sung-Hoon
    • Journal of KIISE:Computer Systems and Theory
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    • v.29 no.3
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    • pp.169-175
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    • 2002
  • This paper is about the hardness of the Election problem in asynchronous distributed systems in which processes can crash but links are reliable. The hardness of the problem is defined with respect to the difficulty to solve it despite failures. It is shown that problems encountered in the system are classified as three classes of problems: F (fault-tolerant), NF (Not fault-tolerant) and NFC(NF-completeness). Among those, the class NFC is the hardest problems to solve. In this paper, we prove that the Election problem is the most difficult problem which belongs to the class NFC.