检索结果-内蒙古大学图书馆

Uncertainty-aware semi-supervised method using large unlabelled and limited labeled COVID-19 data

学校读者我要写书评

暂无评论

arXiv 2021年

作者： Alizadehsani, Roohallah Sharifrazi, Danial Izadi, Navid Hoseini Joloudari, Javad Hassannataj Shoeibi, Afshin Gorriz, Juan M. Hussain, Sadiq Arco, Juan E. Sani, Zahra Alizadeh Khozeimeh, Fahime Khosravi, Abbas Nahavandi, Saeid Islam, Sheikh Mohammed Shariful Acharya, U. Rajendra Deakin University Geelong Australia Department of Computer Engineering School of Technical and Engineering Shiraz Branch Islamic Azad University Shiraz Iran Dept. of Electrical and Computer Engineering Isfahan University of Technology Isfahan Iran Department of Computer Engineering Faculty of Engineering University of Birjand Birjand Iran Computer Engineering Department Ferdowsi University of Mashhad Mashhad Iran Faculty of Electrical and Computer Engineering Biomedical Data Acquisition Lab K. N. Toosi University of Technology Tehran Iran Department of Signal Theory Networking and Communications Universidad de Granada Spain System Administrator Dibrugarh University Assam786004 India Rajaie Cardiovascular Medical and Research Center Iran University of Medical Sciences Tehran Iran Omid Hospital Iran University of Medical Sciences Tehran Iran Institute for Physical Activity and Nutrition Deakin University Melbourne Australia Cardiovascular Division The George Institute for Global Health Australia Sydney Medical School University of Sydney Australia Department of Electronics and Computer Engineering Ngee Ann Polytechnic Singapore Singapore Department of Biomedical Engineering School of Science and Technology Singapore University of Social Sciences Singapore Singapore Department of Bioinformatics and Medical Engineering Asia University Taiwan

The new coronavirus has caused more than 1 million deaths and continues to spread rapidly. This virus targets the lungs, causing respiratory distress which can be mild or severe. The X-ray or computed tomography (CT) images of lungs can reveal whether the patient is infected with COVID-19 or not. Many researchers are trying to improve COVID-19 detection using artificial intelligence. In this paper, relying on Generative Adversarial Networks (GAN), we propose a Semi-supervised Classification using Limited Labelled Data (SCLLD) for automated COVID-19 detection. Our motivation is to develop learning method which can cope with scenarios that preparing labelled data is time consuming or expensive. We further improved the detection accuracy of the proposed method by applying Sobel edge detection. The GAN discriminator output is a probability value which is used for classification in this work. The proposed system is trained using 10,000 CT scans collected from Omid hospital. Also, we validate our system using the public dataset. The proposed method is compared with other state of the art supervised methods such as Gaussian processes. To the best of our knowledge, this is the first time a COVID-19 semi-supervised detection method is presented. Our method is capable of learning from a mixture of limited labelled and unlabelled data where supervised learners fail due to lack of sufficient amount of labelled data. Our semi-supervised training method significantly outperforms the supervised training of Convolutional Neural Network (CNN) in case labelled training data is scarce. Our method has achieved an accuracy of 99.60%, sensitivity of 99.39%, and specificity of 99.80% where CNN (trained supervised) has achieved an accuracy of 69.87%, sensitivity of 94%, and specificity of 46.40%. Copyright © 2021, The Authors. All rights reserved.

关键词： Generative adversarial networks

Antenna Array Enabled Space/Air/Ground communications and Networking for 6G

学校读者我要写书评

暂无评论

arXiv 2021年

作者： Xiao, Zhenyu Han, Zhu Nallanathan, Arumugam Dobre, Octavia A. Clerckx, Bruno Choi, Jinho He, Chong Tong, Wen The School of Electronic and Information Engineering Beihang University Beijing100191 China The Department of Electrical and Computer Engineering The University of Houston HoustonTX77004 United States The Department of Computer Science and Engineering Kyung Hee University Seoul446-701 Korea Republic of The School of Electronic Engineering and Computer Science Queen Mary University of London London United Kingdom The Faculty of Engineering and Applied Science Memorial University St. John’sNLA1C 5S7 Canada The Communications and Signal Processing Group Department of Electrical and Electronic Engineering Imperial College London LondonSW7 2AZ United Kingdom The School of Information Technology Deakin University GeelongVIC3220 Australia The Department of Electronic Engineering Shanghai Jiao Tong University Shanghai200240 China The Wireless Advanced System Competency Centre Huawei Technologies Co. Ltd. OttawaONK2K 3J1 Canada

Antenna arrays have a long history of more than 100 years and have evolved closely with the development of electronic and information technologies, playing an indispensable role in wireless communications and radar. With the rapid development of electronic and information technologies, the demand for all-time, all-domain, and full-space network services has exploded, and new communication requirements have been put forward on various space/air/ground platforms. To meet the ever increasing requirements of the future sixth generation (6G) wireless communications, such as high capacity, wide coverage, low latency, and strong robustness, it is promising to employ different types of antenna arrays (e.g., phased arrays, digital arrays, and reconfigurable intelligent surfaces, etc.) with various beamforming technologies (e.g., analog beamforming, digital beamforming, hybrid beamforming, and passive beamforming, etc.) in space/air/ground communication networks, bringing in advantages such as considerable antenna gains, multiplexing gains, and diversity gains. However, enabling antenna array for space/air/ground communication networks poses specific, distinctive and tricky challenges, which has aroused extensive research attention. This paper aims to overview the field of antenna array enabled space/air/ground communications and networking. The technical potentials and challenges of antenna array enabled space/air/ground communications and networking are presented first. Subsequently, the antenna array structures and designs are discussed. We then discuss various emerging technologies facilitated by antenna arrays to meet the new communication requirements of space/air/ground communication systems. Enabled by these emerging technologies, the distinct characteristics, challenges, and solutions for space communications, airborne communications, and ground communications are reviewed. Finally, we present promising directions for future research in antenna array enabled space/ai

关键词： Beamforming

Reachability as a Unifying Framework for Computing Helicopter Safe Operating Conditions and Autonomous Emergency Landing ⁎

学校读者我要写书评

暂无评论

IFAC-PapersOnLine 2020年第2期53卷 9282-9287页

作者： Matthew R. Kirchner Eddie Ball Jacques Hoffler Don Gaublomme Image and Signal Processing Branch Code D5J1000 Naval Air Warfare Center Weapons Division China Lake CA USA Electrical and Computer Engineering Department University of California Santa Barbara CA 93106 USA Flight Vehicle Modeling and Simulation Branch Naval Air Warfare Center Aircraft Division Patuxent River MD USA

We present a numeric method to compute the safe operating flight conditions for a helicopter such that we can ensure a safe landing in the event of a partial or total engine failure. The unsafe operating region is the complement of the backwards reachable tube, which can be found as the sub-zero level set of the viscosity solution of a Hamilton-Jacobi (HJ) equation. Traditionally, numerical methods used to solve the HJ equation rely on a discrete grid of the solution space and exhibit exponential scaling with dimension, which is problematic for the high-fidelity dynamics models required for accurate helicopter modeling. We avoid the use of spatial grids by formulating a trajectory optimization problem, where the solution at each initial condition can be computed in a computationally efficient manner. The proposed method is shown to compute an autonomous landing trajectory from any operating condition, even in non-cruise flight conditions.

关键词： Reachability Autorotation Optimal Control

Codes with Locality for Two Erasures

学校读者我要写书评

暂无评论

Codes with Locality for Two Erasures

作者： Prakash, N. Lalitha, V. Balaji, S.B. Vijay Kumar, P. Indian Institute of Science Bengaluru560 012 India Signal Processing and Communications Research Centre International Institute of Information Technology Hyderabad500 032 India Department of Electrical Communication Engineering Indian Institute of Science Bengaluru560 012 India Department of Electrical Communication Engineering Indian Institute of Science Bengaluru560 012 India Intel Labs HillsboroOR97124 United States Department of Electrical and Computer Engineering University of Southern California Los AngelesCA United States

Codes with locality are a class of codes introduced by Gopalan et al. to efficiently repair a failed node, by minimizing the number of nodes contacted during repair. An [n,k] systematic code is said to have information locality r , if each message symbol can be recovered by accessing ≤q r other symbols. An [n,k] code is said to have all-symbol locality r , if each code symbol can be recovered by accessing ≤ r other symbols. In this paper, we consider a generalization of codes with all-symbol locality to the case of handling two erasures. We study codes with locality that can recover from two erasures via a sequence of two local, parity-check computations. We refer to these codes as sequential-recovery locally repairable codes (denoted by 2-seq LR codes). Earlier approaches to handling multiple erasures considered recovery in parallel;the sequential approach allows us to potentially construct codes with improved minimum distance. We derive an upper bound on the rate of 2-seq LR codes. We provide constructions based on regular graphs which are rate-optimal with respect to the derived bound. We also characterize the structure of any rate-optimal code. By studying the Generalized Hamming Weights of the dual code, we derive a recursive upper bound on the minimum distance of 2-seq LR codes. We also provide constructions of a family of codes based on Turán graphs, that are optimal with respect to this bound. We also present explicit distance-optimal Turán graph based constructions of 2-seq LR codes for certain parameters. Our approach also leads to a new bound on the minimum distance of codes with all-symbol locality for the single-erasure case. © 1963-2012 IEEE.

关键词： Recovery

Hypertrophic cardiomyopathy diagnosis based on cardiovascular magnetic resonance using deep learning techniques

学校读者我要写书评

暂无评论

Research Square

Research Square 2021年

作者： Sharifrazi, Danial Alizadehsani, Roohallah Izadi, Navid Hoseini Roshanzamir, Mohamad Shoeibi, Afshin Khozeimeh, Fahime Sani, Fariba Alizadeh Sani, Zahra Alizadeh Hussain, Sadiq Harlapur, Chandrashekhar Gorriz, Juan M. Khosravi, Abbas Nahavandi, Saeid Sarrafzadegan, Nizal Islam, Sheikh Mohammed Shariful Department of Computer Engineering School of Technical and Engineering Shiraz Branch Islamic Azad University Shiraz Iran Deakin University Geelong Australia Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan84156-83111 Iran Department of Computer Engineering Faculty of Engineering Fasa University Fasa74617-81189 Iran Computer Engineering Department Ferdowsi University of Mashhad Mashhad Iran Faculty of Electrical and Computer Engineering Biomedical Data Acquisition Lab K. N. Toosi University of Technology Tehran Iran Mashhad University of Medical science Mashhad Iran Department of Cardiac MRI Omid Hospital Tehran Iran Dibrugarh University Assam786004 India Emergency Department Epworth Hospital Geelong Australia Department of Signal Theory Networking and Communications Universidad de Granada Spain Department of Psychiatry University of Cambridge United Kingdom Faculty of Medicine SPPH University of British Columbia VancouverBC Canada Isfahan Cardiovascular Research Center Cardiovascular Research Institute Isfahan University of Medical Sciences Khorram Ave Isfahan Iran Institute for Physical Activity and Nutrition School of Exercise and Nutrition Sciences Deakin University GeelongVIC3220 Australia Cardiovascular Division The George Institute for Global Health Newtown Australia Sydney Medical School University of Sydney Camperdown Australia

Hypertrophic cardiomyopathy (HCM) can lead to serious cardiac problems. HCM is often diagnosed by an expert using cardiovascular magnetic resonance (CMR) images obtained from patients. In this research, we aimed to develop a deep learning technique to automate HCM diagnosis. CMR images of 37421 healthy and 21846 HCM patients were obtained during two years. Images obtained from female patients form 53% of the collected dataset. The mean and standard deviation of the dataset patients’ age are 48.2 and 19.5 years, respectively. Three experts inspected images and determined whether a case has HCM or not. New data augmentation was used to generate new images by employing color filtering on the existing ones. To classify the augmented images, we used a deep convolutional neural network (CNN). To the best of our knowledge, this is the first time CNN is used for HCM diagnosis. We designed our CNN from scratch to reach acceptable diagnosis accuracy. Comparing the designed algorithm output with the experts’ opinions, the method could achieve accuracy of 95.23%, recall of 97.90%, and specificity of 93.06% on the original dataset. The same performance metrics for the designed algorithm on the augmented dataset were 98.53%, 98.70%, and 95.21%, respectively. We have also experimented with different optimizers (e.g. Adadelta and Adagrad) and other data augmentation methods (e.g. height shift and rotation) to further evaluate the proposed method. Using our data augmentation method, accuracy of 98.53% were achieved which is higher than the best accuracy (95.83%) obtained by the other data augmentation methods which have been evaluated. The upper bound on difference between true error rate and empirical error rate of the proposed method has also been provided in order to present better performance analysis. The advantages of employing the proposed method are elimination of contrast agent and its complications, decreased CMR examination time, lower costs for patients and cardiac imagi

关键词： Diagnosis

Straggler mitigation with tiered gradient codes

学校读者我要写书评

暂无评论

arXiv 2019年

作者： Sasi, Shanuja Lalitha, V. Aggarwal, Vaneet Sundar Rajan, B. Department of Electrical Communication Engineering Indian Institute of Science Bangalore 560012 India Purdue University Signal Processing and Communications Research Center IIIT Hyderabad School of Industrial Engineering School of Electrical and Computer Engineering Purdue University West LafayetteIN47907 United States

Coding theoretic techniques have been proposed for synchronous Gradient Descent (GD) on multiple servers to mitigate stragglers. These techniques provide the flexibility that the job is complete when any k out of n servers finish their assigned tasks. The task size on each server is found based on the values of k and n. However, it is assumed that all the n jobs are started when the job is requested. In contrast, we assume a tiered system, where we start with n1≥k tasks, and on completion of c tasks, we start n2-n1more tasks. The aim is that as long as k servers can execute their tasks, the job gets completed. This paper exploits the flexibility that not all servers are started at the request time to obtain the achievable task sizes on each server. The task sizes are in general lower than starting all n2tasks at the request times thus helping achieve lower task sizes which helps to reduce both the job completion time and the total server utilization. Copyright © 2019, The Authors. All rights reserved.

关键词： Gradient methods

OpEn: Code Generation for Embedded Nonconvex Optimization *

学校读者我要写书评

暂无评论

IFAC-PapersOnLine 2020年第2期53卷 6548-6554页

作者： Pantelis Sopasakis Emil Fresk Panagiotis Patrinos Queen’s University Belfast School of Electronics Electrical Engineering and Computer Science (EEECS) and Centre for Intelligent and Autonomous Manufacturing Systems (i-AMS) Ashby Building Stranmillis Road BT9 5AG Belfast Northern Ireland WideFind AB Aurorum 1C 977 75 Luleå Sweden KU Leuven Department of Electrical Engineering (ESAT) STADIUS Center for Dynamical Systems Signal Processing and Data Analytics & Optimization in Engineering (OPTEC) Kasteelpark Arenberg 10 3001 Leuven Belgium

We present Optimization Engine (OpEn): an open-source code generation framework for real-time embedded nonconvex optimization, which implements a novel numerical method. OpEn combines the proximal averaged Newton-type method for optimal control (PANOC) with the penalty and augmented Lagrangian methods to compute approximate stationary points of nonconvex problems. The proposed method involves very simple algebraic operations such as vector products, has a low memory footprint and exhibits very good convergence properties that allow the solution of nonconvex problems on embedded devices. OpEn’s core solver is written is Rust — a modern, high-performance, memory-safe and thread-safe systems programming language — while users can call it from Python, MATLAB, C, C++, ROS or over a TCP socket.

关键词： Embedded numerical optimization nonconvex optimization problems code generation model predictive control moving horizon estimation Rust Robot Operating System

Locally decodable index codes

学校读者我要写书评

暂无评论

arXiv 2019年

作者： Natarajan, Lakshmi Krishnan, Prasad Lalitha, V. Dau, Hoang Department of Electrical Engineering Indian Institute of Technology Hyderabad India Signal Processing & Communications Research Center International Institute of Information Technology Hyderabad India School of Science RMIT University Australia

An index code for broadcast channel with receiver side information is locally decodable if each receiver can decode its demand by observing only a subset of the transmitted codeword symbols instead of the entire codeword. Local decodability in index coding is known to reduce receiver complexity, improve user privacy and decrease decoding error probability in wireless fading channels. Conventional index coding solutions assume that the receivers observe the entire codeword, and as a result, for these codes the number of codeword symbols queried by a user per decoded message symbol, which we refer to as locality, could be large. In this paper, we pose the index coding problem as that of minimizing the broadcast rate for a given value of locality (or vice versa) and designing codes that achieve the optimal trade-off between locality and rate. We identify the optimal broadcast rate corresponding to the minimum possible value of locality for all single unicast problems. We present new structural properties of index codes which allow us to characterize the optimal trade-off achieved by: vector linear codes when the side information graph is a directed cycle;and scalar linear codes when the minrank of the side information graph is one less than the order of the problem. We also identify the optimal trade-off among all codes, including non-linear codes, when the side information graph is a directed 3-cycle. Finally, we present techniques to design locally decodable index codes for arbitrary single unicast problems and arbitrary values of locality. Copyright © 2019, The Authors. All rights reserved.

关键词： Decoding

A Level Set Approach to Online Sensing and Trajectory Optimization with Time Delays ⁎

学校读者我要写书评

暂无评论

IFAC-PapersOnLine 2019年第8期52卷 301-306页

作者： Matthew R. Kirchner Image and Signal Processing Branch Research Directorate Naval Air Warfare Center Weapons Division China Lake CA 93555 USA Electrical and Computer Engineering Department University of California Santa Barbara CA 93106 USA

Presented is a method to compute certain classes of Hamilton-Jacobi equations that result from optimal control and trajectory generation problems with time delays. Many robotic control and trajectory problems have limited information of the operating environment a priori and must continually perform online trajectory optimization in real time after collecting measurements. The sensing and optimization can induce a significant time delay, and must be accounted for when computing the trajectory. This paper utilizes the generalized Hopf formula, which avoids the exponential dimensional scaling typical of other numerical methods for computing solutions to the Hamilton-Jacobi equation. We present as an example a robot that incrementally predicts a communication channel from measurements as it travels. As part of this example, we introduce a seemingly new generalization of a non-parametric formulation of robotic communication channel estimation. New communication measurements are used to improve the channel estimate and online trajectory optimization with time-delay compensation is performed.

关键词： Time Delay Systems Hamilton-Jacobi Equation Generalized Hopf Formula Viscosity Solution Optimal Control Communication Seeking Robotics