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Extended Airtime Fair Scheduling Method for a Zigbee Network |
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Quyen T.T. Bui, Tu Van Chau, Vinh Quang Thai(Institute of Information Technology, Vietnam Academy of Science and Technology, Viet Nam) |
| In a Zigbee network, when many nodes simultaneously send data packets to a Zigbee coordinator through routes (branches), the Zigbee coordinator cannot deal with all signals. Interference and noises are existed during data transmission. This problem is still one of challenges in the network communication. In this paper, we propose an extended airtime fair algorithm in which throughput of a Zigbee network is maximized and fractions of airtime are taken into account. We adapt a utility function that is proposed by Kelly (1997) in maximizing the network throughput; nevertheless, throughput of ... |
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The Development of Ethernet based Radar and ECDIS Image Processing for Voyage Data Recorder |
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Chanmin Jung, Jonggu Kang, Minjung Jin(Hyundai Heavy Industries, Republic of Korea) |
| The function of radar image recording in VDR installed on a ship has been adapted in IMO constraint regulations. For this function, a VDR should be equipped with the dedicated recording device. Recently, as the number of radar on a ship has increased, the number of image grabber also has been increased proportionally. As a result, it could cause to rising costs and drop a competitive price. In this paper, we proposed the technology of radar and ECDIS image processing based on Ethernet for VDR to overcome rising costs and to follow the recent trends of the data communication method. |
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Adaptation of 6LoWPAN to Ship Area Sensor Networks with wired Ethernet backbone and Performance Analysis |
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Sang-Joon Nam, Jonggu Kang, Daekeun Moon(Hyundai Heavy Industries, Republic of Korea) |
| In this paper, we proposed SASN (Ship Area Sensor Networks) model which is integration of wired backbone network (Ethernet) and wireless sensor networks (IPv6 over Low-power Wireless Personal Area Networks, 6LoWPAN). The proposed integrated network model has some limitation compared to sensor networks which is composed of only wired networks because of poor RF environment of inner ship area. We described characteristics of 6LoWPAN in detail and check the suitability of SASN model to ship based on characteristics of 6LoWPAN. In addition, we did performance analysis through simulation. |
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Variable Forgetting Factor RLS Algorithm for Adaptive Echo Cancellation |
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Sethaphak Sukhumalchayaphong, Chawalit Benjangkaprasert(King Mongkut's Institute of Technology Ladkrabang(KMITL), Thailand) |
| Abstract: In this paper the variable forgetting factor recursive least squares (RLS) algorithm for adaptive lattice structure filter for the echo canceller in telephone network is presented. The proposed echo canceller provides high performance and low misadjustment in steady state for all considered noise distributions. |
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Application of Adaptive Notch Filter for Resonance Suppression in Industrial Servo Systems |
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Wook Bahn, Jong-Min Yoon(Seoul National University, Republic of Korea), Nyeon-Kun Hahm, Sang-Sub Lee, Sang-Hoon Lee(RS Automation, Republic of Korea), Dong-Il Cho(Seoul National University, Republic of Korea) |
| An application of an ANF for resonance suppression in industrial servo systems is presented. An on-line frequency estimator is utilized for estimating the resonant frequency. The current command of the servo system is an input to the frequency estimator. The ANF automatically changes its notch frequency according to the estimated resonant frequency values and suppress the resonance. Experiments are performed using an industrial servo system with a belt-drive type load for various load conditions. The developed ANF method identifies the resonant frequency well and suppresses the resonance. |
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On-Off Shaping Commands for Acceleration Limits |
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Yoon-Gyung Sung, Yoon-Sang Min(Chosun University, Republic of Korea) |
| In this paper, an on-off shaping command is presented for reducing the residual oscillation of flexible systems with the acceleration limits of actuators. The flexible systems might be operated with on-off actuators such as in spacecrafts, cranes and manufacturing machines. Because of limited acceleration of actuators, the on-off commands would be distorted. The non-ideal on-off commands result in residual oscillation to flexible systems which is degrading control accuracy and performance. Therefore, an analytical solution of on-off command generation with acceleration limits is developed by u |
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