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Spectrum sensing for cognitive OFDM system using free probability theory

Journal of Information and Computational Science 2011年第10期8卷 1847-1859页

作者： Wang, Lei Zheng, Baoyu Cui, Jingwu Meng, Qingmin Institute of Signal Processing and Transmission Nanjing University of Posts and Telecommunications Nanjing 210003 China Key Lab. of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Ministry of Education China

Free probability theory as a main branch of random matrix theory is a valuable tool for describing the asymptotic behavior of multiple systems, especially for those with large random matrices. In this paper, by using free probability theory, a new spectrum sensing scheme for cognitive OFDM system is proposed, which shows how asymptotic free behavior of random matrices and the property of Wishart distribution can be used to assist spectrum sensing for cognitive radios in such scenario. Simulation results show that the proposed scheme has a better detection performance than the energy detection technique and the maximum-minimum eigenvalue scheme even for the case of a small sample of observations. © 2011 by Binary Information Press.

关键词： Cognitive radio

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Designing Passive Filters for Harmonic Reduction in a Noisy System Based on Discrete Wavelet Transform

Designing Passive Filters for Harmonic Reduction in a Noisy ...

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2011 4th IEEE International Conference on computer Science and Information technology(ICCSIT 2011)

作者： Hamid Rahimi Esfahani Farshad Kiyoumarsi Rasoul Amirfattahi Ebrahim Borzabadi Department of Electrical Engineering Young Researchers Club Islamic Azad University Department of Computer Engineering Islamic Azad University Digital Signal processing Research Lab. Department of Electrical and Computer EngineeringIsfahan University of Technology Department of Electrical Engineering Islamic Azad University

ISBN: (纸本)9781612848334

In this paper,among different methods of signal processing,wavelet transform is chosen due to its advantages over other *** show wavelet transform capabilities, first an HVDC system which has noise on its output current is *** the first step noise is removed by applying discrete wavelet *** the next steps,harmonic problem is resolved thorough appropriate passive *** this paper,we suppose that not only low order harmonics exist in the output current,but also high order *** results indicate that we can obtain a good passive filter design for harmonic reduction by decomposing a signal into its harmonic components via applying discrete wavelet transform.

关键词： wavelet multi-resolution decomposition passive filter for harmonic reduction harmonic detection wavelet-based threshold de-noising method

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Finding protein active sites using approximate sub-graph isomorphism

Finding protein active sites using approximate sub-graph iso...

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Middle East Conference on Biomedical Engineering (MECBME)

作者： Mohammad Ebrahim Abbasi Dezfouli Seyed Shahriar Arab Emad Fatemizadeh Najmeh Hosseynimanesh Electrical Engineering Department BiSIPL (Biomedical Image and Signal Processing Lab) Sharif University of Technology Tehran Iran School of Computer Science Institute for Research in Fundamental Sciences Tehran Iran

Prediction of the amino acids that have a catalytic effect on the enzymes is a major stage in appointing the activity of the enzymes and classification. The biological activity of a protein usually depends on the existence of a small number of amino acids. Recently, many algorithms have been proposed in the literature for finding these amino acids which are complex and time consuming. In this paper, we will introduce a new method for predicting the active sites that will use the spatial coordinates and the type of amino acids that contain the active sites. In order to increase the speed we use an approximate graph isomorphism algorithm. Furthermore, this algorithm allows us to find several active sites for a protein and order them according to a RMSD (Root Mean Square Deviation) number which has several applications in biology.

关键词： Proteins Amino acids Approximation algorithms Protein engineering Classification algorithms Databases

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The flight delays propagation analysis model for hub airports based on the danger model theory

International Journal of Digital Content Technology and its ...

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International Journal of Digital Content technology and its Applications 2011年第6期5卷 229-235页

作者： Ding, Jianli Li, Huafeng College of Computer Science and Technology Civil Aviation University of China Tianjin 300300 China Tianjin Key Lab for Advanced Signal Processing Civil Aviation University of China Tianjin 300300 China Department of computer Science Tangshan Teacher College Tangshan 063000 China

Flight delays have caused the civil aviation industry huge losses. It is very important to estimate the number of the flight delays. Consider the operational characteristics of the airport's flight;this thesis develops a model which draws lessons from danger model theory. It combines the danger model with the immune system theory to solve the airdrome flight antigen recognition. In every time segment, we can use this model to forecast the effect of the flight delays. For a large domestic flight airport's data in summer, this model can accurately predict the flight delay in every period. The airport can refer to the quantitative relationship and establish flights delay early warning mechanism according to the initial delayed time.

关键词： Airports

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Single and Multiple Estimation in MIMO Rician Fading Channels

Single and Multiple Estimation in MIMO Rician Fading Channel...

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International Conference on computer Communication and Management（ICCCM 2011）

作者： Hamid Nooralizadeh Shahriar Shirvani Moghaddam Faculty Member of Electrical Engineering Department Islamshahr Branch Islamic Azad University Digital Communications Signal Processing (DCSP) Research Lab. Faculty of Electrical and Computer Engineering Shahid Rajaee Teacher Training University (SRTTU)

In this paper, the performance of the Single-Estimation （SE） and Multiple-Estimation （ME） is investigated in Multiple-Input Multiple-Output （MIMO） Rician fading channels using the Maximum Likelihood （ML） technique and the new Shifted Scaled Least Squares （SSLS） estimator. Analytical and numerical results show that both estimators have lower error in the case of ME than SE. Moreover, it is seen that increasing the channel Rice factor improves the performance of the SSLS estimator. However, the ML estimator cannot exploit the knowledge of the Rician fading channel. As a result, in fast fading MIMO channels with a short coherence time, the SSLS estimator can be used in SE mode. On the other hand, the ML estimator has only good results in the case of ME. This estimator is appropriate for slow fading MIMO channels with a long coherent time.

关键词： Rician fading channel Single Estimation （SE） Multiple Estimation （ME） MIMO ML SSLS.

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Design, fabrication and Helium Ion Microscope patterning of suspended nanomechanical graphene structures for NEMS applications

Design, fabrication and Helium Ion Microscope patterning of ...

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International Conference on Solid State Sensors and Actuators (TRANSDUCERS)

作者： M. Annamalai S. Mathew V. Viswanathan C. Fang D. S. Pickard M. Palaniapan Centre of Integrated Circuit Failure Analysis & Reliability Singapore Plasmonics & Advanced Imaging Technology Laboratory Department of Electrical and Computer Engineering National University of Singapore Singapore Signal Processing & VLSI Lab Singapore

This paper investigates the potential uses of graphene nanomechanical devices for NEMS applications fabricated using Helium Ion Microscope (HIM). Suspended nanomechanical graphene drum structures of diameter (~2 - 3 μm) and thickness ranging from few atomic layers (~10 Å) to about 11 nm have been fabricated and characterized using Atomic Force Microscopy (AFM). The initial suspension profile and the thickness of the fabricated structures have been obtained using AFM. FEM results suggest that these structures can vibrate in the range of several MHz. Their small size and the higher operating frequencies make them well suitable for mass sensing applications with sensitivities greater than 10 -21 g Hz -1 which is more than three orders of magnitude improvement over silicon based structures. The initial suspended graphene membranes have been patterned using HIM to obtain multiple z-axis flexures with sub-10nm feature sizes.

关键词： Silicon Nanoelectromechanical systems Helium Microscopy Nanostructures Gold Fabrication

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Traffic speed measurement using Spatio-Temporal model and frequency domain analysis

Traffic speed measurement using Spatio-Temporal model and fr...

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

作者： Arucha Rungchokanun Vutipong Areekul Supakorn Siddhichai Hiroaki Kunieda Kasetsart Signal & Image Processing Laboratory (KSIP Lab) Department of Electrical Engineering Kasetsart University Thailand Image Technology Laboratory National Electronics and Computer Technology Center Pathum Thani Thailand Department of Communication and Integrated Systems Tokyo Institute of Technology Meguro Tokyo Japan

In traffic monitoring applications, traffic speed is an important parameter of traffic management. The method for traffic speed measurement using video based on Spatio-Temporal (ST) model and frequency domain analysis is proposed in this paper. This method is designed to be able to measure the traffic speed in every pattern of road. The novel of proposed method is unfolding the edge information on ST model and analyse them in frequency domain to determine traffic speed. The proposed method is evaluated by compare with actual speed. The traffic speed is measured accurately 97.1%.

关键词： Analytical models Sensors Pixel Image sensors Monitoring

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A new filter bank algorithm for enhancement of early signs of ischemic stroke in brain CT images

A new filter bank algorithm for enhancement of early signs o...

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IEEE International Conference on signal and Image processing Applications (ICSIPA)

作者： Mehdi Sajjadi Rassoul Amirfattahi Mohammad Reza Ahmadzadeh Mohammad Ali Saghafi Digital Signal Processing Research Lab Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan Iran Smart Engineering System Research Group Department of Electrical Electronics & System Engineering University Kebangsaan Malaysia Bangi Selangor Darul Ehsan Malaysia

Brain CT images are very useful in diagnosis of cerebrovascular accidents (CVA). These images contain too many information. But most of the times, provided information is contaminated by noise and suffer from poor contrast. On the other hand, there are certain parts of the brain image that is really important to radiologist, while other image details are more or less confusing. This sparks the need for customized enhancement of brain CT images. Translation-invariant wavelet transform is being widely used in most of image processing tasks including image enhancement. This transform is calculated with a filter bank algorithm, called algorithme àtrous. In this paper we propose a filter bank structure similar to algorithme àtrous. This structure is more redundant and offers greater selectivity and flexibility to enhance desired features of brain CT images.

关键词： Computed tomography Wavelet transforms Image edge detection Lesions Image enhancement

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SAR Image Classification Combining Structural and Statistical Methods

SAR Image Classification Combining Structural and Statistica...

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International IEEE Conference on signal-Image Technologies and Internet-Based System

作者： Narcisse Talla Tankam Janvier Fotsing Albert Dipanda Emmanuel Tonye Computer Science Department University Institute of Technology-University of Dschang (IUTFV-UDs) Bandjoun Cameroon LE2i ESIREM University of Burgundy Dijon France Lab of Electronics and Signal Processing (LETS) National High School of Engineering (ENSP-UYI) Yaounde Cameroon

The main objective of this paper is to develop a new technique of SAR image classification. This technique combines structural parameters, including the Sill, the slope, the fractal dimension and the range, with statistical methods in a supervised image classification. Thanks to the range parameter, we define the suitable size of the image window used in the proposed approach of supervised image classification. This approach is based on a new way of characterising different classes identified on the image. The first step consists in determining relevant area of interest. The second step consists in characterising each area identified, by a matrix. The last step consists in automating the process for image classification.

关键词： Image classification Fractals Mathematical model Statistical analysis Structural engineering Educational institutions Equations

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Online signature verification using combination of two classifiers

Online signature verification using combination of two class...

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Iranian Conference on Machine Vision and Image processing

作者： Saeidi, M. Amirfattahi, R. Amini, A. Sajadi, M. Digital Signal Processing Research Lab. Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan Iran

ISBN: (纸本)9781424497065

The objective of signature verification is to distinguish forgery signature from genuine one. Online signature is the one which is registered through electronic devices such as digitizers and stored on computers in time sequence form. In this kind of signatures in addition to location information, time information such as speed and acceleration is stored. In this paper after accomplishment of some pre-processing procedures like normalization of signature size, smoothing and elimination of rotation on signatures using algorithms based on extremum matching of signals and ant colony, their time duration will be equalized. Afterwards, similarities between signatures will be determined using extended regression and finally will try to distinguish between forgery signatures from genuine one using support vector machine (SVM). The suggested online verification system is tested on SVC2004 signature set which is related to the first international signature verification competition and results are compared to respective results of participants. The results state that suggested method exhibits equal error rate (EER) of %4.3 in skilled forger group. © 2010 IEEE.

关键词： Support vector machines

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