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A theoretical signal processing framework for linear diffusion MRI: Implications for parameter estimation and experiment design

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NEUROimage 2017年 161卷 206-218页

作者： Varadarajan, Divya Haldar, Justin P. Univ Southern Calif Signal & Image Proc Inst Ming Hsieh Dept Elect Engn Los Angeles CA 90089 USA

The data measured in diffusion MRI can be modeled as the Fourier transform of the Ensemble Average Propagator (EAP), a probability distribution that summarizes the molecular diffusion behavior of the spins within each voxel. This Fourier relationship is potentially advantageous because of the extensive theory that has been developed to characterize the sampling requirements, accuracy, and stability of linear Fourier reconstruction methods. However, existing diffusion MRI data sampling and signal estimation methods have largely been developed and tuned without the benefit of such theory, instead relying on approximations, intuition, and extensive empirical evaluation. This paper aims to address this discrepancy by introducing a novel theoretical signal processing framework for diffusion MRI. The new framework can be used to characterize arbitrary linear diffusion estimation methods with arbitrary q-space sampling, and can be used to theoretically evaluate and compare the accuracy, resolution, and noise-resilience of different data acquisition and parameter estimation techniques. The framework is based on the EAP, and makes very limited modeling assumptions. As a result, the approach can even provide new insight into the behavior of model-based linear diffusion estimation methods in contexts where the modeling assumptions are inaccurate. The practical usefulness of the proposed framework is illustrated using both simulated and real diffusion MRI data in applications such as choosing between different parameter estimation methods and choosing between different q-space sampling schemes.

关键词： Diffusion MRI Sampling theory Orientation distribution function Ensemble average propagator

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Color image encryption based on chaotic systems and elliptic curve ElGamal scheme

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signal processing 2017年 141卷 109-124页

作者： Wu, Jiahui Liao, Xiaofeng Yang, Bo Southwest Univ Coll Elect & Informat Engn Chongqing Key Lab Nonlinear Circuits & Intelligen Chongqing 400715 Peoples R China

Color image can provide more information than gray image, so it is used more widely in the field of the communication. In recent years, how to safely encrypt images has received increasing attention. Numerous previous image encryption algorithms are based on the symmetric encryption algorithm, but each pair of users communicating with symmetric encryption algorithm can only use the key that others do not know, so when the sender communicates with a receiver multiple times or sends the message to multiple receivers, the key number will grow at a geometric rate, and key management will become a burden on the users. In this paper, we propose an asymmetric image encryption algorithm for the advantages that the key groups and the number of keys in secret information transmission among multiple people are very small, and key transmission mode is relatively simple and secure. In our algorithm, first, the plain image is compressed and then the color image is encrypted by using the improved 4D cat map followed by asymmetric encryption which is based on elliptic curve ElGamal encryption, and finally, the encrypted image is globally diffused. The performance analysis is performed on key spaces, key sensitivity, the capability of resisting statistical attacks, differential attacks, known plaintext attacks and chosen plaintexticiphertext attacks and quality evaluation metrics of decrypted image. simulation results show that the proposed algorithm has better security comparing with other algorithms. (C) 2017 Elsevier B.V. All rights reserved.

关键词： Chaos Four-dimensional cat map Elliptic curve (EC) ElGamal cryptosystem Three-dimensional Lorenz system

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Staring array sensor model for simulation implementation 4

Staring array sensor model for simulation implementation

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4th South African Conference on Sensors, MEMS and Electro-Optical systems (SMEOS)

作者： Willers, Cornelius J. Willers, Maria S. Airbus DS Optron Pty Ltd Nellmapius DrPOB 8859 ZA-0046 Centurion South Africa Denel Dynam POB 7412 ZA-0046 Centurion South Africa

ISBN: (纸本)9781510605138;9781510605145

A comprehensive model for staring array simulation is described. The model covers all effects from photon signal generation through to detection and processing in the staring array sensor. The model follows the signal flow from photon generation, through a staring focal plane array (FPA) from the detector, through several conversions in the read out integrated circuit (ROIC) and finally conversion to a digital signal. Spatial nonuniformity modeling for photoresponse, dark current generation and source follower offset is included. The list of noise sources includes: photon noise, quantum conversion uncertainty, dark noise, kTC noise, source follower noise and quantization noise. Several components with (simplified) nonlinear responses are also modeled: sense node capacitance variation with charge, source follower nonlinearity and nonlinearity in the digital conversion. The code implementations take images as input, applying the various processes independently on individual pixels (e.g., shot noise) or on complete images (e.g., spatial nonuniformity). Some noise sources vary temporally across frames (shot, thermal, kTC) while other noise sources are fixed across frames (fixed pattern noises). The application of the model is demonstrated by tracing the signal path from source to sensor output, with intermediate results along the path. The model is implemented in Python (as part of the pyradi open source computational radiometry module) and in a C++ image simulation. The purpose with this work is to predict what the performance of a given sensor will be in terms of image appearance, given the devices specifications and key design parameters. The execution of this work lead to the important recommendation that nonuniformity correction for infrared sensors should be performed at well fill levels corresponding to the minimum and maximum in the scene, not to fixed percentage levels in the charge well. The objective with this work is to provide a 'generic' model that can be

关键词： staring array performance image simulation photoresponse nonuniformity (PRNU) focal plane array (FPA)

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Vehicle density, vehicle speed and packet inter-arrival time analysis in IEEE 802.11p EDCA based VANETs

Vehicle density, vehicle speed and packet inter-arrival time...

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International Conference on signal, image, Vision and their Applications (SIVA )

作者： Yacine Harkat Abderrahmane Amrouche Division Microélectronique et Nanotechnologie (DMN) Centre de Développement des Technologies Avancées (CDTA) Speech Com. Signal Proc. Lab. FEI USTHB Cité 20 août 1956 Baba Hassen Algiers Algeria Speech Communication and Signal Processing Laboratory Faculty of Electronics and Computer Sciences USTHB P.O. Box 32 El Alia Bab Ezzouar Algiers Algeria

ISBN: (纸本)9781538671214;9781538671207

Vehicular ad-hoc networks (VANETs) are considered as a key component of future Intelligent Transportation systems (ITS). The IEEE 802.11p standard modifies the IEEE 802.11a to adapt to vehicular networks. In the MAC sublayer, the IEEE 802.11p standard uses Enhanced Distributed Channel Access (EDCA) mechanism to provide differentiated media access by defining four access categories (ACs). However, VANET characteristics such as network size, high speed, fast topology changes, traffic density, can greatly affect network performance, especially for the MAC sub-layer. Therefore, important issues arise about the ability of this standard to provide reliable and efficient services for vehicular environment. Since test beds are still limited, computer simulations are very useful for the automobile industry. This paper present a simulation-based analysis of the impact of the vehicle density, vehicle speed and packet inter-arrival time on the performance of the IEEE 802.11p EDCA mechanism in VANET. Throughput, average delay and packet delivery ratio (PDR) were considered as evaluation metrics. The obtained results confirm that IEEE 802.11p EDCA provides an effective differentiation service mechanism that can be adapted to critical ITS applications. However, we noted a performance degradation in extreme cases. As in large number of communicating vehicles, very high speeds, and high transmission rates.

关键词： Throughput Delays Standards Vehicular ad hoc networks Data models Mobile computing

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2017 4th International Conference on signal processing and Integrated Networks, SPIN 2017

2017 4th International Conference on Signal Processing and I...

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4th International Conference on signal processing and Integrated Networks, SPIN 2017

ISBN: (纸本)9781509027972

The proceedings contain 122 papers. The topics discussed include: brain tumor segmentation in multispectral MR images;achieving performance speed-up in FPGA based 4:2 compressor using fast carry-chains;performance of auditory features using MFCC and Teager-Kaiser energy computation for non-intrusive speech quality assessment;preamble-based synchronization for OFDM/OQAM systems in AWGN channel;thermal image acquisition and segmentation of human foot;a geographic routing algorithm based on cat swarm optimization for vehicular ad-hoc networks;comparison of parallel image scanning methods for achieving better throughput;modeling and simulation study of cerebrospinal fluid circulation in human brain;a recursive framework for bias field estimation and segmentation of noisy brain MR images;speech emotion recognition with deep learning;improving closet pair key distribution scheme using neighbour node connectivity prediction;a novel approach towards identification of in-flight situation based on air traffic control conversations;texture analysis of gradient images for benign-malignant mass classification;REER: relay based energy efficient routing for intra body sensor network (intra-WBSN);optimization of secondary user capacity under efficient bandwidth utilization in Cr through Alc-Pso;artificial neural network approach for modeling of photovoltaic module;and design, simulation and a comparative study of square, rectangular, triangular and dual beamed RF MEMS switch for switching applications.

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Analytical performance Verification of FCS-MPC Applied to Power Electronic Converters: A Model Checking Approach 18

Analytical Performance Verification of FCS-MPC Applied to Po...

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IEEE 18th Workshop on Control and modeling for Power Electronics (COMPEL)

作者： Novak, Mateja Dragicevic, Tomislav Blaabjerg, Frede Nyman, Ulrik Mathias Aalborg Univ Dept Energy Technol Aalborg Denmark Aalborg Univ Dept Comp Sci Aalborg Denmark

ISBN: (纸本)9781509053261

Since the introduction of finite control set model predictive control (FCS-MPC) in power electronics the algorithm has been missing an important aspect that would speed up its implementation in industry: a simple method to verify the algorithm performance. This paper proposes to use a statistical model checking (SMC) method for performance evaluation of the algorithm applied to power electronics converters. SMC is simple to implement, intuitive and it requires only an operational model of the system that can be simulated and checked against properties. Device under test for control algorithm application in this paper is a standard 2-level voltage source converter (VSC) with LC output filter used for uninterruptible power supply (UPS) systems. The performance of control algorithm is verified using the UPPAAL SMC toolbox and the behavior is compared to simulation results obtained from equivalent MATLAB/Simulink model and measurements from experimental set-up. performance results are presented in terms of probabilities with corresponding uncertainties for calculated difference between the reference capacitor voltage value and the measured output voltage, and a simple moving average value. Algorithm's performance is tested with parameter uncertainties introduced in the model as well.

关键词： Estimation Field programmable gate arrays OFDM Modulation Filtration Clocks signal processing algorithms

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FIMTrack: An open source tracking and locomotion analysis software for small animals

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PLOS COMPUTATIONAL BIOLOGY 2017年第5期13卷 e1005530-e1005530页

作者： Risse, Benjamin Berh, Dimitri Otto, Nils Klaembt, Christian Jiang, Xiaoyi Univ Edinburgh Sch Informat Edinburgh Midlothian Scotland Univ Munster Fac Math & Comp Sci Munster Germany Univ Munster Dept Behav & Neuronal Biol Munster Germany

Imaging and analyzing the locomotion behavior of small animals such as Drosophila larvae or C. elegans worms has become an integral subject of biological research. In the past we have introduced FIM, a novel imaging system feasible to extract high contrast images. This system in combination with the associated tracking software FIMTrack is already used by many groups all over the world. However, so far there has not been an in-depth discussion of the technical aspects. Here we elaborate on the implementation details of FIMTrack and give an in-depth explanation of the used algorithms. Among others, the software offers several tracking strategies to cover a wide range of different model organisms, locomotion types, and camera properties. Furthermore, the software facilitates stimuli-based analysis in combination with built-in manual tracking and correction functionalities. All features are integrated in an easy-to-use graphical user interface. To demonstrate the potential of FIMTrack we provide an evaluation of its accuracy using manually labeled data. The source code is available under the GNU GPLv3 at https://***/i-git/FIMTrack and precompiled binaries for Windows and Mac are available at http://***.

关键词： Algorithms Animal models Animals Applied mathematics Arthropoda Biological locomotion Biology and life sciences Caenorhabditis Caenorhabditis elegans Computer and information sciences Computer software Developmental biology Drosophila Drosophila melanogaster Engineering and technology Experimental organism systems image processing Insects Invertebrates Larvae Life cycles Mathematics Medicine and health sciences Model organisms Nematoda Organisms Physical sciences Physiology Research and analysis methods Research Article signal processing simulation and modeling

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Incremental Adaptive EEG Classification of Motor imagery-based BCI

Incremental Adaptive EEG Classification of Motor Imagery-bas...

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International Joint Conference on Neural Networks (IJCNN)

作者： Hai-Jun Rong Changjun Li Rong-Jing Bao Badong Chen State Key Laboratory for Strength and Vibration of Mechanical Structures Shaanxi Key Laboratory of Environment and Control for Flight Vehicle School of Aerospace Engineering Xi’an Jiaotong University China Institute of Artificial Intelligence and Robotics School of the Electronic and Information Engineering Xi’an Jiaotong University China

Generally, electroencephalogram (EEG) signals recorded from the brain computer interface (BCI) systems are very noisy and non-stationary, which may affect the online performance of classifiers established from the prior session heavily. In order to address such problems, the classifiers should also be capable of adapting the change of EEG automatically during the processing of evaluation. In this paper, we propose an incremental adaptive EEG classification scheme. In this scheme, an extended sequential adaptive fuzzy inference system (ESAFIS) is used to evolve its structure dynamically and adapts the classifier automatically online to address the non-stationarity of the EEG signals. ESAFIS is an evolving system, wherein the fuzzy rules are evolved based on the modified influence of the rule. This paper presents the classification of 2-class motor imagery EEG based on ESAFIS with adaptive strategy. simulations are conducted based on two datasets: one is the BCI Competition IV dataset 2b and the other one is recorded from our own BCI experiments. Compared to other methods such as ELM and LDA, the simulation results demonstrate that the proposed scheme produces better classification results.

关键词： Electroencephalography Feature extraction Training image segmentation Windows Adaptive systems Brain modeling

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Development MEMS Acoustic Emission Sensors

Development MEMS Acoustic Emission Sensors

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作者： Avila Gomez, Adrian Enrique University of South Florida

学位级别：Ph.D.

The purpose of this research is to develop MEMS based acoustic emission sensors for structural health monitoring. Acoustic emission (AE) is a well-established nondestructive testing technique that is typically used to monitor for fatigue cracks in structures, leaks in pressurized systems, damages in composite materials or impacts. This technology can offer a precise evaluation of structural conditions and allow identification of imminent failures or minor failures that can be addressed by planned maintenances routines. AE causes a burst of ultrasonic energy that is measured as high frequency surface vibrations (30 kHz to 1 MHz) generated by transient elastic waves that are typically emitted from growing cracks at the interior of the structure. The AE sensor marketplace is currently dominated by bulky and expensive piezoelectric transducers that are wired to massive multichannel data acquisition systems. These systems are complex to operate with the need of signal conditioning units and near proximity pre-amplifiers for each sensor that demands a fairly complicated wiring requirements. Furthermore, due to the high prices of conventional AE sensors and associated instrumentation, and the current requirements in sensor volumes for smart transportation infrastructure, it is undeniable that new AE technology is required for affordable structural health monitoring. The new AE technology must deliver comparable performance at one or two orders of magnitude lower cost, size and weight. MEMS acoustic emission (AE) sensors technology has the potential to resolve several of these traditional sensor’s shortcomings with the advantage of possible integration of on-chip preamplifier while allowing substantially cost reduction due to the batch processing nature of MEMS technology. This study will focus on filling some of the major existing gaps between current developments in MEMS acoustic emission sensors and commercial piezoelectric sensors, such as sensor size, signal-to-noise r

关键词： Microelectromechanical systems Damping Capacitive simulation modeling Microfabrication

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Proceedings of the 2017 IEEE International Conference on Communication and signal processing, ICCSP 2017

Proceedings of the 2017 IEEE International Conference on Com...

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6th IEEE International Conference on Communication and signal processing, ICCSP 2017

ISBN: (纸本)9781509038008

The proceedings contain 321 papers. The topics discussed include: performance analysis of efficient routing protocols to improve quality of service in wireless sensor networks;implementation of automatic test pattern generator for asynchronous circuits using SRAM based FPGA;creating music with movement;closed loop control of a new non-isolated quadratic boost converter;design, modeling and simulation of low cost robust electric fence energizer in LT SPICE;a cooperative mechanism for wireless energy harvesting and spectrum sharing in 5G networks;segmentation and recognition of text from image using pattern matching;hybrid failure handling approach for guaranteed service in cloud computing environment;PAPR reduction for OFDM systems using DCT and helical interleaver in modified PTS technique;QRS complex detection using cuckoo search optimization algorithm;a comparative fault analysis in series compensated line during power swing;a review on resource efficient polar decoders- present and past;a novel technique of fault detection using wavelet transform during power swing;classification of EMI signatures for smart grid;a comparative study of multichannel and single channel accelerometer sensors for communication in oil wells;analysis of feature based object mining and tagging algorithm considering different levels of occlusion;and design of infant monitoring system to reduce the risk of sudden infant death syndrome.

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