• Title/Summary/Keyword: RTS method

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Introduction of RTS Method and Load Calculation Program (RTS법의 개요 및 프로그램 소개)

  • Kim, Kang-San;Kim, Yong-Chan;Oh, Myung-Do
    • Proceedings of the SAREK Conference
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    • 2008.06a
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    • pp.1067-1072
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    • 2008
  • This paper introduces the RTS method developed by the ASHRAE. In addition, a load calculation program was developed based on the RTS method and then the calculation logic and procedure are explained in detail. The developed program was designed to allow easy and precise predictions of the building load.

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Introduction of RTS Method and Load Calculation Program (RTS 법의 개요 및 프로그램 소개)

  • Kim, Kang-San;Kim, Yong-Chan;Oh, Myung-Do
    • Proceedings of the SAREK Conference
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    • 2006.06a
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    • pp.519-524
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    • 2006
  • This paper introduces the RTS method developed by the ASHRAE. In addition, a load calculation program was developed based on the RTS method and then the calculation logic and procedure are explained in detail. The developed program was designed to allow easy and precise predictions of the building load.

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MAC Performance Enhancement by Efficient Hidden Node Detection in Infrastructure Mode IEEE 802.11 Wireless LANs (Infrastructure Mode IEEE 802.11 무선랜 시스템에서 효율적인 은닉 단말 발견 방법을 통한 MAC 성능 개선)

  • Choi, Woo-Yong
    • Journal of Korean Institute of Industrial Engineers
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    • v.34 no.2
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    • pp.246-254
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    • 2008
  • In this paper, a new efficient hidden node detection method is proposed to decide whether the RTS/CTS mechanism is necessary to resolve the hidden node problem for the data transmission of each node in infrastructure mode IEEE 802.11 wireless LANs. The nodes, for which the RTS/CTS mechanism is found to be not necessary by the hidden node detection method, can transmit their data frames without performing the RTS/CTS exchange. Only the nodes, for which the RTS/CTS mechanism is found to be necessary by the hidden node detection method, perform the RTS/CTS exchange before their data frame transmissions.

Prediction of the IGS RTS Correction using Polynomial Model at IOD Changes (IOD 변화 시점에서 다항식 모델을 사용한 IGS RTS 보정정보 예측)

  • Kim, Mingyu;Kim, Jinho;Kim, Jeongrae
    • Journal of Advanced Navigation Technology
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    • v.24 no.6
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    • pp.533-539
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    • 2020
  • Real-time service (RTS) provided by IGS provides correction for GNSS orbit and clock via internet, so it is widely used in fields that require real-time precise positioning. However, the RTS signal may be lost due to an unstable Internet environment. When signal disconnection occurs, signal prediction can be performed using polynomial models. However, the RTS changes rapidly after the GNSS navigation message issue of data (IOD) changes, so it is difficult to predict when signal loss occurs at that point. In this study, we proposed an algorithm to generate continuous RTS correction information by applying the difference in navigation trajectory according to IOD change. The use of this algorithm can improve the accuracy of RTS prediction at IOD changes. After performing optimization studies to improve RTS prediction performance, the predicted RTS trajectory information was applied to precision positioning (PPP). Compared to the conventional method, the position error is significantly reduced, and the error increase along with the signal loss interval increase is reduced.

Asymmetric RTS/CTS for Exposed Node Reduction in IEEE 802.11 Ad Hoc Networks

  • Matoba, Akihisa;Hanada, Masaki;Kanemitsu, Hidehiro;Kim, Moo Wan
    • Journal of Computing Science and Engineering
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    • v.8 no.2
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    • pp.107-118
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    • 2014
  • One interesting problem regarding wireless local area network (WLAN) ad-hoc networks is the effective mitigation of hidden nodes. The WLAN standard IEEE 802.11 provides request to send/clear to send (RTS/CTS) as mitigation for the hidden node problem; however, this causes the exposed node problem. The first 802.11 standard provided only two transmission rates, 1 and 2 Mbps, and control frames, such as RTS/CTS assumed to be sent at 1 Mbps. The 802.11 standard has been enhanced several times since then and now it supports multi-rate transmission up to 65 Mbps in the currently popular 802.11n (20 MHz channel, single stream with long guard interval). As a result, the difference in transmission rates and coverages between the data frame and control frame can be very large. However adjusting the RTS/CTS transmission rate to optimize network throughput has not been well investigated. In this paper, we propose a method to decrease the number of exposed nodes by increasing the RTS transmission rate to decrease RTS coverage. Our proposed method, Asymmetric Range by Multi-Rate Control (ARMRC), can decrease or even completely eliminate exposed nodes and improve the entire network throughput. Experimental results by simulation show that the network throughput in the proposed method is higher by 20% to 50% under certain conditions, and the proposed method is found to be effective in equalizing dispersion of throughput among nodes.

A Short-Term Prediction Method of the IGS RTS Clock Correction by using LSTM Network

  • Kim, Mingyu;Kim, Jeongrae
    • Journal of Positioning, Navigation, and Timing
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    • v.8 no.4
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    • pp.209-214
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    • 2019
  • Precise point positioning (PPP) requires precise orbit and clock products. International GNSS service (IGS) real-time service (RTS) data can be used in real-time for PPP, but it may not be possible to receive these corrections for a short time due to internet or hardware failure. In addition, the time required for IGS to combine RTS data from each analysis center results in a delay of about 30 seconds for the RTS data. Short-term orbit prediction can be possible because it includes the rate of correction, but the clock correction only provides bias. Thus, a short-term prediction model is needed to preidict RTS clock corrections. In this paper, we used a long short-term memory (LSTM) network to predict RTS clock correction for three minutes. The prediction accuracy of the LSTM was compared with that of the polynomial model. After applying the predicted clock corrections to the broadcast ephemeris, we performed PPP and analyzed the positioning accuracy. The LSTM network predicted the clock correction within 2 cm error, and the PPP accuracy is almost the same as received RTS data.

Random Telegraph Signals of the Scaling-down NOR Flash Cells

  • An, Ho-Joong;Lee, Gae-Hun;Kil, Gyu-Hyun;Song, Yun-Heup
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.02a
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    • pp.250-250
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    • 2010
  • The random telegraph signal (RTS) for the NOR flash cell scaling is investigated. An innovative method to suppress the RTS, based on the device engineering, is proposed. By optimizing the channel doping profile and using the high-k tunnel dielectric, it is confirmed from three-dimensional (3-D) simulation, that the $V_{th}$ amplitude, dueto RTS, is significantly suppressed, from approximately 0.5 to 0.07 V in the middle of the channel at 45 nm NOR Flash technology. From this result, it is expected that the proposed method to suppress the RTS amplitude is essential for further cell size scaling in Flash memory.

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Throughput Analysis Based on Collision Probability in 802.11 Networks (802.11 네트워크의 충돌확률 기반 성능 분석)

  • Jin, Hyun-Joon;Song, Myong-Lyol
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.14 no.2
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    • pp.93-100
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    • 2014
  • IEEE 802.11 Wireless LAN Medium Access Control(MAC) supports two transmission methods, a DCF basic and a RTS/CTS in contention-based access. Even though the RTS/CTS method has been optionally introduced to solve the hidden terminal problem, it is able to produce better performance in some network environments than the basic transmission method. In this paper, the collision probability of wireless channel is mathematically analyzed and applied to measure network throughput using real transmission parameters so that a reference value between throughputs of two methods is obtained. We also confirmed that control signal rates affect overall network throughput and evaluated network throughputs considering collision probability, number of stations, and contention window size of Backoff between two methods respectively.