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Absolute Gradient Algorithm for Adaptive IIR Notch Filter

Absolute Gradient Algorithm for Adaptive IIR Notch Filter

International Conference on Electrical engineering/Electronics, computer, Telecommunications and Information technology, ECTI-CON

作者： A. Nosan R. Punchalard The Computer Engineering Graduate Program Faculty of Engineering Mahanakorn University of Technology Thailand Department of Telecommunication Engineering Mahanakorn University of Technology Bangkok Thailand

The gradient algorithm used absolute value of error signal as a criterion to adjust the filter coefficient of adaptive IIR notch filter is presented in this paper. The objective is to estimate or track the frequency of a single sinusoidal signal corrupted by additive white Gaussian noise. The proposed algorithm can solve the problem of selecting an initial condition as met in the previous method. Moreover, it also has a high convergence speed.

关键词： IIR filters Adaptive filters Filtering algorithms Frequency estimation Convergence Signal processing algorithms Mathematical model

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Frequency modulation using digital sinusoidal oscillator

Frequency modulation using digital sinusoidal oscillator

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International Conference on Electrical engineering/Electronics, computer, Telecommunications and Information technology, ECTI-CON

作者： R. Punchalard A. Nosan Department of Telecommunication Engineering Mahanakorn University of Technology Bangkok Thailand The Computer Engineering Graduate Program Faculty of Engineering Mahanakorn University of Technology Thailand

This paper presents an alternative method to generate the digital frequency modulation (FM) signal. By summing an information signal m(k) with the oscillating frequency ω 0 and putting the result into the cosine function of digital oscillator coefficient which is −2 cos (ω 0 +m(k)), the FM signal is obtained. computer simulations are conducted to show the validity of the proposed FM signal generator

关键词： Frequency modulation Oscillators Finite impulse response filter Bandwidth Adaptive filters Amplitude shift keying

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Performance Evaluation of Channel Reservation Schemes for Reservation-based MAC Protocols with Different Priorities

Performance Evaluation of Channel Reservation Schemes for Re...

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International Symposium on Communications and Informaiton Technologies

作者： Nitthita Chirdchoo Piya Kovintavewat Pisit Vanichchanunt Norrarat Wattanamongkhol Lunchakorn Wuttisittikulkij Warakorn Srichavengsup Telecommunication Engineering Program Nakhon Pathom Rajabhat University Department of Electrical and Computer Engineering King Mongkut's University of Technology North Bangkok Department of Electrical Engineering Chulalongkorn University Department of Computer Engineering Thai-Nichi Institute of Technology

ISBN: (纸本)9781467311564

This paper considers the problem of channel reservation schemes for reservation-based MAC protocols with different priorities in wireless communication networks. A framework for designing such channel reservation protocols based on p-persistent is introduced. This framework allows us to explore several different prioritization mechanisms which are devised to serve different prioritization policies or requirements. This leads to the development of five channel reservation schemes, namely, FPT+MP, FPT+MLT, FPT+SCS, FPT+PCP and FPT+HFF. The average number of successful reservations for users of different priorities is evaluated as a primary performance measure. Unlike other previous works where different priorities exhibit strict differentiation, our success ratio (γ) is defined to illustrate how much different priorities are differentiated. In doing so, we seek for a channel reservation scheme that can satisfy the required γ, while maximizing the channel utilization. Numerical results show that the combined scheme of FPT+MP and FPT+SCS schemes is the most effective scheme, possessing all desirable key features.

关键词： MAC protocol Performance Evaluation Scheme Wireless networks Performance metrics

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Heart wall myofibers are arranged in minimal surfaces to optimize organ function (vol 109, pg 9253, 2012)

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PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 2012年第49期109卷 20166-20166页

作者： Savadjiev, Peter Strijkers, Gustav J. Bakermans, Adrianus J. Piuze, Emmanuel Zucker, Steven W. Siddiqi, Kaleem [a]Psychiatry Neuroimaging Laboratory and Laboratory for Mathematics in Imaging Brigham and Women’s Hospital Harvard Medical School Boston MA 02215 [b]Department of Biomedical Engineering Eindhoven University of Technology 5600 MB Eindhoven The Netherlands [c]School of Computer Science and Centre for Intelligent Machines McGill University Montréal Canada H3A 2A7 and [d]Departments of Computer Science and Biomedical Engineering and Program in Applied Mathematics Yale University New Haven CT 06520-8285

Heart wall myofibers wind as helices around the ventricles, strengthening them in a manner analogous to the reinforcement of concrete cylindrical columns by spiral steel cables [Richart FE, et al. (1929) Univ of Illinois, Eng Exp Stn Bull 190]. A multitude of such fibers, arranged smoothly and regularly, contract and relax as an integrated functional unit as the heart beats. To orchestrate this motion, fiber tangling must be avoided and pumping should be efficient. Current models of myofiber orientation across the heart wall suggest groupings into sheets or bands, but the precise geometry of bundles of myofibers is unknown. Here we show that this arrangement takes the form of a special minimal surface, the generalized helicoid [Blair DE, Vanstone JR (1978) Minimal Submanifolds and Geodesics 13-16], closing the gap between individual myofibers and their collective wall structure. The model holds across species, with a smooth variation in its three curvature parameters within the myocardial wall providing tight fits to diffusion magnetic resonance images from the rat, the dog, and the human. Mathematically it explains how myofibers are bundled in the heart wall while economizing fiber length and optimizing ventricular ejection volume as they contract. The generalized helicoid provides a unique foundation for analyzing the fibrous composite of the heart wall and should therefore find applications in heart tissue engineering and in the study of heart muscle diseases. [PUBLICATION ABSTRACT]

关键词： myocardium myofiber geometry diffusion tensor MRI

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The Usefulness of Overheard Information for Collision Avoidance in a Single-hop Underwater Acoustic Networks

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Procedia engineering 2012年 32卷 329-335页

作者： N. Chirdchoo W.-S. Soh K.C. Chua P. Kovintavewat W. Cheunta Telecommunication Program Faculty of Science and Technology Nakhon Pathom Rajabhat UniversityNakhon Pathom 73000 Thailand Department of Electrical and Computer Engineering National University of Singapore Singapore Computer Industrial Technology Program Faculty of Science and Technology Nakhon Pathom Rajabhat UniversityNakhon Pathom73000 Thailand

A MAC protocol that depends on overheard information for its collision avoidance, such as Carrier Sense Multiple Access (CSMA) [1], may not work well in underwater, due to the long propagation delay characteristic of an underwater acoustic (UWA) channel. In such channel, the overheard information may already become obsolete by the time it reaches the node and, thus, should not be taken into account in the collision avoidance mechanism. Intuitively, the degree of usefulness of overheard information plays an important role in determining the network performance for channel listening-based MAC protocols. In this paper, we analytically study the usefulness of overheard information for collision avoidance in two different channel listening-based MAC protocols: (1) CSMA [1] and (2) Aloha-CA [2]. From our study, it is shown that the overheard information is beneficial for collision avoidance only if certain conditions can be satisfied. More specifically, in order for a node that overhears an ongoing transmission to be able to utilize the extracted information for collision avoidance, the node must be within a bounded region that is determined by the relative positions of the sender and the receiver, the packet's transmission time, as well as the length of the packet's header. Based on this analysis, we also present the “usefulness index (U)” which is defined as the degree of usefulness of information overheard.

关键词： Underwater acoustic network MAC protocol design Channel listening Collision avoidance

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Reversible JPEG Data Hiding Based on EMD

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通讯和计算机（中英文版） 2012年第10期9卷 1135-1141页

作者： Wen-Chung Kuo Shao-Hung Kuo Department of Computer Science and Information Engineering National Yunlin University of Science & Technology Yunlin 672 Taiwan Graduate School of Engineering Science and Technology Doctoral Program National Yunlin University of Science and Technology Yunlin 640 Taiwan

As the rapid growth of smart phone technology, people have a lot of digital image information such as digital photos or videos. Both data hiding and data compression are very important technologies in image processing field. On the overview, it seems that there is no relationship between data hiding and data compression because data hiding mechanisms focus on information security and data compression mechanisms emphasize the compression ratio. However, the more secret data is embedded, the more capacity the stego image increases. Actually, they are closely related. Until now, there are many literatures to discuss the secret data how to be embedded into the media image and keeps the original capacity as soon as possible. In this paper, a reversible data hiding scheme based on EMD data hiding and JPEG (Joint Picture Experts Group) compression technology will be proposed. According to experimental results, the authors can prove that our proposed scheme maintains high embedding capacity, security and good compression ratio.

关键词：数据隐藏 JPEG EMD 可逆数字图像信息数据嵌入压缩技术数据压缩

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Preparation of NIR Reflective Brown Pigment

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Procedia engineering 2012年 32卷 895-901页

作者： T. Thongkanluang N. Chirakanphaisarn P. Limsuwan Ceramics Technology Program Faculty of Science and Technology Suratthani Rajabhat University Suratthani 84100 Thailand Department of Computer Technology and Engineering Faculty of Technology and Engineering Siam Technology College Bangkok 10600 Thailand Department of Physics Faculty of Science King Mongkut's University of Technology Thonburi Bangkok 10140 Thailand

Complex inorganic brown pigments having a high near infrared solar reflectance have been synthesized. Fe2O3 is the host component and mixtures of Sb2O3, SiO2, Al2O3, and TiO2 were used as the guest components. Sb2O3, SiO2, Al2O3, and TiO2 were mixed into 40 different compositions. It was found that a sample, denoted by S31, with a composition of Fe2O3, Sb2O3, SiO2, Al2O3, and TiO2 of 70, 10, 12, 2 and 6 wt% respectively, gives a maximum near infrared solar reflectance of 46.7%. Brown pigment colours were measured in CIE L*a*b* colour index. The S31 pigment powder was then prepared as a reflective coating material with different amounts of pigment powder from 4-8 g in 100 g of ceramic glaze. The prepared materials were sprayed on the biscuit clay tiles for reflectance measurements. It was found that 5 g of S31 pigment powder mixed with 100 g of ceramic glaze gives the highest near-infrared reflectance value of 41.3%. The newly synthesized pigment is a suitable ceramic roof coating for its high reflectance performance and the durability performing once the ceramic roof installed on house.

关键词： Brown pigment Ceramic glaze Near-infrared reflectance

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A Statistical Model for Uplink Intercell Interference with Power Adaptation and Greedy Scheduling

A Statistical Model for Uplink Intercell Interference with P...

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IEEE Vehicular technology Conference

作者： Hina Tabassum Ferkan Yilmaz Zaher Dawy Mohamed Slim Alouini Electrical Engineering Program King Abdullah University of Science and Technology (KAUST) Department of Electrical and Computer Engineering American University of Beirut (AUB)

ISBN: (纸本)9781467318808

This paper deals with the statistical modeling of uplink inter-cell interference (ICI) considering greedy scheduling with power adaptation based on channel conditions. The derived model is implicitly generalized for any kind of shadowing and fading environments. More precisely, we develop a generic model for the distribution of ICI based on the locations of the allocated users and their transmit powers. The derived model is utilized to evaluate important network performance metrics such as ergodic capacity, average fairness and average power preservation numerically. Monte-Carlo simulation details are included to support the analysis and show the accuracy of the derived expressions. In parallel to the literature, we show that greedy scheduling with power adaptation reduces the ICI, average power consumption of users, and enhances the average fairness among users, compared to the case without power adaptation.

关键词： statistical models (nuclear) inter-cell interference greedy method Consumers Power (Psychology) ICI up link Performance metrics Energy sources Shadowing (Histology) average power TRANSMITTING

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Application of UPFC to improve the LVRT capability of wind turbine generator

Application of UPFC to improve the LVRT capability of wind t...

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Australasian Universities Power engineering Conference, AUPEC

作者： Yasser M. Alharbi A. M. Shiddiq Yunus A. Abu Siada Electrical and Computer Engineering Department Curtin University of Technology Perth Australia Mechanical Engineering Department Energy Conv. Study Program State of Polytechnic Ujung Pandang Makassar Indonesia

Variable speed wind turbine generators installation has been significantly increased worldwide in the last few years. Voltage sag at the grid side may call for the disconnection of the wind turbine from the grid as under such faults it may not comply with the recent developed grid codes for wind energy conversion systems (WECS). In this paper, a Unified Power Flow Controller (UPFC) is applied to improve the low voltage ride through (LVRT) capability of doubly fed induction generator (DFIG)-based WECS during voltage sag at the grid side. Simulation is carried out using MATLAB/Simulink software. Results show that UPFC can significantly improve the LVRT capability of DFIG-based WECS and hence maintaining wind turbine connection to the grid during certain levels of voltage sag at the grid side.

关键词： Voltage fluctuations Wind turbines Reactive power Voltage control Power system stability Generators Wind energy

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Impact of intermittent misfire and fire-through on the performance of full converter based WECS

Impact of intermittent misfire and fire-through on the perfo...

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Australasian Universities Power engineering Conference, AUPEC

作者： A. M. Shiddiq Yunus M. A. S. Masoum A. Abu Siada Mechanical Engineering Department Energy Conv. Study Program State of Polytechnic Ujung Pandang Makassar Indonesia Electrical and Computer Engineering Department Curtin University of Technology Perth Australia

The integration of wind turbines into modern power grids has significantly increased during the last decade. The wind turbine equipped with full converter based wind energy Conversion System (FCWECS) represented about 20.3% of the worldwide total wind capacity in 2003. Since FCWECS is equipped with a voltage source inverter (VSI), it is vulnerable that misfire and fire-through may occur within the VSI switches. In this paper, impact of these switching malfunctions on FCWECS performance is investigated and discussed. Detailed simulations of the system under study are carried out using Matlab/Simulink to highlight the influence of these converter internal faults on PCC voltage, DC link voltage and shaft speed, as well as generator active and reactive power. Furthermore, compliance of the FCWECS with Spain fault ride through (FRT) grid codes is also investigated.

关键词： Inverters Wind turbines Generators Educational institutions Reactive power Voltage fluctuations Insulated gate bipolar transistors

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