• Title/Summary/Keyword: NTP

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Comparison of NTP and Master-Slave Network Synchronization Methods in in-door Environment (실내 망 동기화를 위한 NTP와 Master-Slave 방식의 비교)

  • Lee Hyojung;Kwon Youngmi
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.42 no.1
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    • pp.61-66
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    • 2005
  • Location Positioning is a major technology for ubiquitous computing. Recently the research on Location Positioning using UWB is on going. In order to construct an in-door location network, synchronization of base stations is very important. NTP is Popularly used as clock synchronization protocol ranging from LAN to WAN. Also Master-Slave scheme is the simplest method to synchronize in-door network. We compare and analyze NTP and Master-Slave schemes according to the statistical channel model for indoor multipath propagation environment. In this paper, error ranges are calculated at various circumstances that in-door network expands from one primary base station into several base stations. We compared the correctness of NTP and Master-Slave synchronization methods. NTP is more reasonable synchronization protocol in in-door environment.

NTP-ERSN verification with C5G7 1D extension benchmark and GUI development

  • Lahdour, M.;El Bardouni, T.;El Hajjaji, O.;Chakir, E.;Mohammed, M.;Al Zain, Jamal;Ziani, H.
    • Nuclear Engineering and Technology
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    • v.53 no.4
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    • pp.1079-1087
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    • 2021
  • NTP-ERSN is a package developed for solving the multigroup form of the discrete ordinates, characteristics and collision probability of the Boltzmann transport equation in one-dimensional cartesian geometry, by combining pin cells. In this work, C5G7 MOX benchmark is used to verify the accuracy and efficiency of NTP-ERSN package, by treating reactor core problems without spatial homogenization. This benchmark requires solutions in the form of normalized pin powers as well as the vectors and the eigenvalue. All NTP-ERSN simulations are carried out with appropriate spatial and angular approximations. A good agreement between NTP-ERSN results with those obtained with OpenMC calculation code for seven energy groups. In addition, our studies about angular and mesh refinements are carried out to produce better quality solution. Moreover, NTP-ERSN GUI has also been updated and adapted to python 3 programming language.

An Synchronization Characteristics Analysis of Public NTP Servers in Internet (인터넷상의 공용 NTP서버가 동기화 특성 분석)

  • 오지석;성순용;김영호
    • Proceedings of the Korean Information Science Society Conference
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    • pp.621-623
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    • 1998
  • 본 논문에서는 공용 접근이 가능한 NTO 서버들에 대한 동기화 특성을 조사, 분석했다. 분석 주요 항목은 서버 신뢰도, 정확도 그리고 오프셋(offeset)과 전송지연의 관계이다. 이러한 분석을 위해 NTP알고리즘에서 최적 시간 동기를 위해 선택하는 값인 클럭 옻프셋, 일주지연, 분산 그리고 동기화 거리를 사용하였다. 분석 결과는동기화 거리 값의 경우 최대 700ms의 정도의 차이를 보이고, 분산의 경우 최대 300ms정도의 차이를 나타내었다. 또한 전송 지연과 오프셋은 타워 분포를 보이며, 이는 그간의 오프셋 근거의 단순 선택이 효율적이지 못할 수 있음을 보여주었다. 본 논문에서 살펴본 NTP서버 동기화 특성은 많은 NTP 서버중 최적의 조건을 찾는데 유용하게 쓰일 수 있다.

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A study on the Set-top Box System Recovery using Network Time Synchronization (네트워크 시간 동기화를 활용한 효과적 셋톱박스 시스템 복구 방안에 관한 연구)

  • Han, Kyung-Sik;Kim, In-Ki;Min, Tae-Hoon;Sonh, Seung-Il
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.647-649
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    • 2013
  • This paper is the study of effective recovery system in the android set-top box, using NTP (Network Time Protocol). Because of Response to the user react quickly in case of a set-top box, needs compared to other electronic products, set-top box is one of always powered features to work at home. But general-purpose OS such as Android-based set-top box have to reset for cache & main memory initialization. In this paper, we introduce system reset & recovery by NTP client utilizing.

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Accomplishments and Challenges of Vietnamese's NTP-NRD during the 1st Stage(2010-2015) (베트남 신 농촌개발운동 1단계 (2010-2015) 사업의 성과와 한계)

  • Ko, Soonchul
    • Journal of Agricultural Extension & Community Development
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    • v.23 no.4
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    • pp.459-470
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    • 2016
  • The purpose of this study was to examine the accomplishments and problems of National Target Program on New Rural Development(NTP-NRD) of the Vietnam government during the 1st stage(2011-2015). Based on the literature review and interview, the following suggestions were drawn with related to 19 criteria and 39 indicators; 1) the relationship between the overall goal and 19 criteria as its measures seems to be inconsistence, so that the meet of the 19 criteria regarded as the goal of the NTP-NRD, 2) there was no measures for the communes, where met the requirement of 19 criteria early, 3) most indicators were output oriented, while outcome level were little, 4) it needed to adjust for the some indicators as the implementation unit from commune level to more wider spatial level.

Characterization of a Noncanonical Purine dNTP Pyrophosphatase from Archaeoglobus fulgidus

  • Im Eun-Kyoung;Hong Chang-Hyung;Back Jung-Ho;Han Ye-Sun;Chung Ji-Hyung
    • Journal of Microbiology and Biotechnology
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    • v.16 no.7
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    • pp.1144-1148
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    • 2006
  • DNA can oxidatively be deaminated by ROS, which converts DNA base amino groups to keto groups and can trigger abnormal mutations, resulting in mutagenesis in organisms. In this study, a noncanonical purine dNTP pyrophosphatase (AfPPase) from a hyperthermophilic archaeon Archaeoglobus fulgidus, which hydrolyzes aberrant nucleoside triphosphates, was overexpressed in E. coli, purified, and characterized. The purified AfPPase showed remarkably high activity for XTP and dITP, suggesting that the 6-keto group of these nucleotides is critical for the reactivity. Under optimal reaction conditions, the reaction rate for these substrates was about 120 times that with dGTP. Therefore, AfPPase may play a significant role in DNA repair by hydrolysis of noncanonical nucleotides before they are misincorporated into DNA.

Removal of Volatile Organic Compounds by Photo-Catalytic Oxidation

  • Lee, Byeong-Kyu;Jung, Kwang-Ryun
    • Journal of Korean Society for Atmospheric Environment
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    • v.16 no.E
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    • pp.39-46
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    • 2000
  • Volatile Organic Compounds (VOCs) are considered as the precursors of atmospheric ozone and photochemical smog formation. In particular, chemical plants have produced a lot of VOCs and thus they have been forced to reduce or remove air emissions from the on-site chemical facilities. For the effective removal of VOCs produced in the chemical plants, the authors employed a titanium oxide(TiO$_2$) mediated photo-catalytic oxidation method. The initiation methods employed in this study to produce oxygen radicals for th photo-catalytic oxidation of the VOCs were Ultra-Violet(UV), Non-Thermal Plasma(NTS), and a combination of Uv and NTP. This study focused on a comparison of the removal efficiencies of VOCs as a function of the initiation method such as NTP and/or UV techniques. Removal efficiency change of VOCs as was investigated as a function of the wavelength of the UV lamp(254, 302, and 365 nm) and the degree of TiO$_2$ coating (10 and 30%). In this study, it was identified that removal efficiencies if the VOCs under the normal air environment were much better than those under the nitrogen gas environment containing small amount of oxygen. Removal efficiency by NTP technique was much better than the UV or the combination of UV and NTP techniques. In a comparison if UV wavelengths employed, it was found that shorter wavelength showed better removal efficiency, compared with longer ones. When the removal efficiencies of VOCs were compared in terms of the degree of TiO$_2$ coating, the higher TiO$_2$coating showed better removal efficiency that the lower TiO$_2$ coating

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Time Synchronization of the Monitoring Data for the VoIP User Assessment of Voice Quality Measurement (인터넷전화 이용자 체감품질 측정을 위한 측정데이터 간의 시간동기화)

  • Kweon Tae-Hoon;Hwang Hyae-Jeong;Lee Seog-Ki;Song Han-Chun;Won Seung-Young
    • The Journal of the Korea Contents Association
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    • v.5 no.4
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    • pp.227-236
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    • 2005
  • We study, in terms of VoIP user assessment of voice quality, the synchronization of measurement system is important. Commonly the synchronization system uses NTP(Network Time Protocol) or GPS(Global Positioning System), these synchronization method has time error of distance, system overhead of data processing, and system specialized clock error. we propose and implement the synchronization method to correct time error between two measurement system in the internet. So the time synchronization of systems can get time error, then user assessment of voice quality become reliable.

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Generation Characteristics of Ozone and NOx and Particle Removal in the Electrostatic Precipitators (코로나 방전 방식에 따른 전기집진기의 오존, NOx 발생 및 입자제거 특성)

  • Noh, Kwang-Chul;Lee, Young-Ho;Oh, Myung-Do
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.27 no.10
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    • pp.1442-1449
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    • 2003
  • We investigated the amount of the toxic gases emitted from the Electrostatic Precipitators(ESPs), which are currently used as the indoor air cleaners. The existing wire-to-plate(WTP) and neddle-to-plate(NTP) types of ESP designs are considered as the experimental corona dischargers. Using the voltage, the polarity of wire, the number of needles of NTP as the input variables, we studied the generation characteristics of ozone and $NO_{x}$ and the particle removal efficiency in the ESPs. As the results, we found out that the concentration of ozone, $NO_{2}$ and $NO_{x}$ is increased with increasing the voltage and the number of needles, but the amount of NO is decreased. And we observed that the generation rates of ozone and $NO_{x}$ are mainly related with the corona region through the photographs. Finally the experimental results showed that the particle removal efficiency of ESP with WTP type charger is more superior to that with NTP type chargers at the same voltage.

A Study on System for Synchronization of Multiple UAVs and Ground Control System (무인이동체 및 지상국 컴퓨터 간의 시간 정보 동기화를 위한 시스템 연구)

  • Lee, Won-Seok;Lee, Woon-Sang;Song, Hyoung-Kyu
    • Journal of the Semiconductor & Display Technology
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    • v.19 no.1
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    • pp.11-16
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    • 2020
  • In this paper, system that includes multiple unmanned aerial vehicles (UAVs) are considered. The vehicles are equipped with a mission computer for a specific mission and equipment. The mission equipment operates based on the time of mission computer. Also, data collected by flight computer and mission computer is saved with the time of each operating system. Generally, time offset between multiple computers always exists, though the computers are connected to the Internet. When the data collected by multiple computers is combined, the time offset causes damage on reliability of the combined data. Computers that connected to the Internet are synchronized by network time protocol (NTP). This paper proposes a system that the time of multiple mission computers are synchronized by the same NTP server to minimize the time offset. In the results of the measurement, the system time offset of multiple mission computer is maintained within 10ms from the system time of the server computer.