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arXiv 2020年

作者： Zhang, Jinglin Xu, Wenjun Gao, Hui Pan, Miao Han, Zhu Zhang, Ping Key Lab of Universal Wireless Communications Ministry of Education Beijing University of Posts and Telecommunications Beijing100876 China Key Laboratory of Trustworthy Distributed Computing and Service Ministry of Education Beijing University of Posts and Telecommunications Beijing100876 China Department of Electrical and Computer Engineering University of Houston HoustonTX77204 United States University of Houston HoustonTX77004 United States Department of Computer Science and Engineering Kyung Hee University Seoul446-701 Korea Republic of State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing100876 China

Millimeter wave (mmWave) communications can potentially meet the high data-rate requirements of unmanned aerial vehicle (UAV) networks. However, as the prerequisite of mmWave communications, the narrow directional beam tracking is very challenging because of the three-dimensional (3D) mobility and attitude variation of UAVs. Aiming to address the beam tracking difficulties, we propose to integrate the conformal array (CA) with the surface of each UAV, which enables the full spatial coverage and the agile beam tracking in highly dynamic UAV mmWave networks. More specifically, the key contributions of our work are three-fold. 1) A new mmWave beam tracking framework is established for the CA-enabled UAV mmWave network. 2) A specialized hierarchical codebook is constructed to drive the directional radiating element (DRE)-covered cylindrical conformal array (CCA), which contains both the angular beam pattern and the subarray pattern to fully utilize the potential of the CA. 3) A codebook-based multiuser beam tracking scheme is proposed, where the Gaussian process machine learning enabled UAV position/attitude predication is developed to improve the beam tracking efficiency in conjunction with the tracking-error aware adaptive beamwidth control. Simulation results validate the effectiveness of the proposed codebook-based beam tracking scheme in the CA-enabled UAV mmWave network, and demonstrate the advantages of CA over the conventional planner array in terms of spectrum efficiency and outage probability in the highly dynamic scenarios. Copyright © 2020, The Authors. All rights reserved.

关键词： Millimeter waves

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Using Local Expiration Timers to Reduce Buffer Utilisation When Using Epidemic Diffusion

Using Local Expiration Timers to Reduce Buffer Utilisation W...

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IEEE Global communications Conference

作者： Enrique Hernandez-Orallo Carlos Borrego Carlos Tavares Calafate Juan-Carlos Cano Universitat Politecnica de Valencia Valencia Spain Department of Information and Communications Engineering Autonomous University of Barcelona Barcelona Spain Department of Computer Engineering (DISCA) Universitat Politècnica de València Valencia Spain

ISBN: (数字)9781728109626

ISBN: (纸本)9781728109633

Opportunistic Networking (OppNet) is a consolidated networking paradigm based on intermittent connectivity between wireless mobile devices. In OppNet, mobile nodes store, carry and forward messages by taking advantage of wireless ad-hoc communication opportunities. A common approach for the diffusion of information in OppNet is the epidemic protocol, which carries out a fast information diffusion at the expense of increasing the usage of local buffers on mobile nodes. Nevertheless, due to this high local buffer usage and the usually reduced hardware capabilities of Internet of Things (IoT) devices, OppNet utilisation for IoT applications can be severely reduced. Therefore, a way to reduce the local buffer usage is to set a message expiration timer that forces the removal of old messages in the local buffers. Nevertheless, since dropping messages may reduce the speed of message diffusion, we propose to conveniently adjust this expiration timer, using a model to obtain the optimal expiration times that achieve performances similar to those ideal approaches where no expiration is considered, with a significant reduction of local buffer usage.

关键词： Mathematical model Biological system modeling Protocols Sociology Statistics Mobile nodes

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Locality in index coding for large min-rank

arXiv

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arXiv 2019年

作者： Natarajan, Lakshmi Dau, Hoang Krishnan, Prasad Lalitha, V. Department of Electrical Engineering Indian Institute of Technology Hyderabad Department of Electrical and Computer Systems Engineering Monash University Melbourne Australia Signal Processing & Communications Research Center International Institute of Information Technology Hyderabad India

An index code is said to be locally decodable if each receiver can decode its demand using its side information and by querying only a subset of the transmitted codeword symbols instead of observing the entire codeword. Local decodability can be a beneficial feature in some communication scenarios, such as when the receivers can afford to listen to only a part of the transmissions because of limited availability of power. The locality of an index code is the ratio of the maximum number of codeword symbols queried by a receiver to the message length. In this paper we analyze the optimum locality of linear codes for the family of index coding problems whose min-rank is one less than the number of receivers in the network. We first derive the optimal trade-off between the index coding rate and locality with vector linear coding when the side information graph is a directed cycle. We then provide the optimal trade-off achieved by scalar linear coding for a larger family of problems, viz., problems where the min-rank is only one less than the number of receivers. While the arguments used for achievability are based on known coding techniques, the converse arguments rely on new results on the structure of locally decodable index codes. Copyright © 2019, The Authors. All rights reserved.

关键词： Decoding

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Author Correction: Morphogenetic metasurfaces: unlocking the potential of Turing patterns

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Nature communications 2024年第1期15卷 3701页

作者： Thomas Fromenteze Okan Yurduseven Chidinma Uche Eric Arnaud David R Smith Cyril Decroze University of Limoges CNRS XLIM UMR 7252 F-87000 Limoges France. thomas.fromenteze@unilim.fr. Centre for Wireless Innovation (CWI) Institute of Electronics Communications and Information Technology (ECIT) Queen's University Belfast Belfast BT3 9DT UK. University of Limoges CNRS XLIM UMR 7252 F-87000 Limoges France. Center for Metamaterials and Integrated Plasmonics Department of Electrical and Computer Engineering Duke University Durham NC 27708 USA.

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Joint Task Assignment and Resource Allocation for D2D-Enabled Mobile-Edge Computing

Joint Task Assignment and Resource Allocation for D2D-Enable...

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作者： Xing, Hong Liu, Liang Xu, Jie Nallanathan, Arumugam College of Information Engineering Shenzhen University Shenzhen518060 China Department of Electronic and Information Engineering Hong Kong Polytechnic University Hong Kong Hong Kong School of Information Engineering Guangdong University of Technology Guangzhou510006 China School of Electronic Engineering and Computer Science Queen Mary University of London LondonE1 4NS United Kingdom National Mobile Communications Research Laboratory Southeast University Nanjing211189 China

With the proliferation of computation-extensive and latency-critical applications in the 5G and beyond networks, mobile-edge computing (MEC) or fog computing, which provides cloud-like computation and/or storage capabilities at the network edge, is envisioned to reduce computation latency as well as to conserve energy for wireless devices (WDs). This paper studies a novel device-to-device (D2D)-enabled multi-helper MEC system, in which a local user solicits its nearby WDs serving as helpers for cooperative computation. We assume a time division multiple access (TDMA) transmission protocol, under which the local user offloads the tasks to multiple helpers and downloads the results from them over orthogonal pre-scheduled time slots. Under this setup, we minimize the computation latency by optimizing the local user's task assignment jointly with the time and rate for task offloading and results downloading, as well as the computation frequency for task execution, subject to individual energy and computation capacity constraints at the local user and the helpers. However, the formulated problem is a mixed-integer non-linear program (MINLP) that is difficult to solve. To tackle this challenge, we propose an efficient algorithm by first relaxing the original problem into a convex one, and then constructing a suboptimal task assignment solution based on the obtained optimal one. Furthermore, we consider a benchmark scheme that endows the WDs with their maximum computation capacities. To further reduce the implementation complexity, we also develop a heuristic scheme based on the greedy task assignment. Finally, the numerical results validate the effectiveness of our proposed algorithm, as compared against the heuristic scheme and other benchmark ones without either joint optimization of radio and computation resources or task assignment design. © 1972-2012 IEEE.

关键词： Resource allocation

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Ultra-wideband (UWB) phase shifter on multimode resonator: Concept, theory, and design

Ultra-wideband (UWB) phase shifter on multimode resonator: C...

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2018 IEEE MTT-S International Wireless Symposium, IWS 2018

作者： Lyu, Yun-Peng Zhu, Lei Cheng, Chong-Hu School of Electronic Science and Engineering Nanjing University of Posts and Communications Nanjing210003 China Department of Electrical and Computer Engineering Faculty of Science and Technology University of Macau China

ISBN: (纸本)9781538663462

In this paper, a new universal design method of ultra-wideband (UWB) phase shifter on multimode resonators (MMR) is proposed and developed. The generalized topology of proposed phase shifters based on MMR is presented and their phase properties with J and K inverters are both analyzed. On the one hand, the phase shift performances are found dominated by the excitation of resonant modes, regardless of J and K inverters. On the other hand, the proposed 45° and 90° phase shifters can easily obtain bandwidth more than 110% with simple geometry and single-layer structure compared with other reported designs. The working principle and design method are given. Meanwhile, theoretical analysis of magnitude and phase shift bandwidth are carried out. Finally, a prototype of 90° phase shifter is fabricated and tested. The measured results well verify our design concept. © 2018 IEEE.

关键词： Topology

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Chiang Mai earthquakes prediction: A dynamic time warping embed the polynomial contraint

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Journal of computers (Taiwan) 2019年第2期30卷 68-83页

作者： Kongthanarit, Suppavich Praneetpolgrang, Prasong Bajracharya, Jigyasa Petchartee, Somrak Department of Computer Engineering Chulalongkorn University Bangkok Thailand Department of Information Technology Sripatum University Bangkok Thailand Department of Electronics and Communications Engineering Thammasat University Kathmandu Nepal Brownien Laboratory Innovation Center CAT Telecom Thailand

Earthquakes are sudden natural disasters that endanger people’s lives and properties all around the world. Although much work has been done in the field of prevention of such damages via timely prediction the work needs to be tailored to the area-specific dataset for optimum accuracy. With the time series seismic event data of Chiang Mai for 4 years, we focus our study to provide a prediction of future earthquakes here by using z-normalization and a polynomial constraint in DTW on CUDA-enabled accelerators. By comparing polynomial constraint to Sakoe-Chiba Band as well as Itakura band, we have verified our work to have reduced the percentage of computational time and improved accuracy. The aim of this paper is to demonstrate a prediction accuracy of 0.95. © 2019 computer Society of the Republic of China. All rights reserved.

关键词： Polynomials

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A mixture of experts model for predicting persistent weather patterns

arXiv

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arXiv 2019年

作者： Pérez-Ortiz, M. Gutiérrez, P.A. Tino, P. Casanova-Mateo, C. Salcedo-Sanz, S. Computer Laboratory University of Cambridge United Kingdom Dpt. of Computer Science and Numerical Analysis University of Córdoba Spain School of Computer Science University of Birmingham United Kingdom Department of Civil Engineering: Construction Infrastructure and Transport Universidad Politécnica de Madrid Madrid Spain Department of Signal Processing and Communications University of Alcalá Spain

Weather and atmospheric patterns are often persistent. The simplest weather forecasting method is the so-called persistence model, which assumes that the future state of a system will be similar (or equal) to the present state. Machine learning (ML) models are widely used in different weather forecasting applications, but they need to be compared to the persistence model to analyse whether they provide a competitive solution to the problem at hand. In this paper, we devise a new model for predicting low-visibility in airports using the concepts of mixture of experts. Visibility level is coded as two different ordered categorical variables: cloud height and runway visual height. The underlying system in this application is stagnant approximately in 90% of the cases, and standard ML models fail to improve on the performance of the persistence model. Because of this, instead of trying to simply beat the persistence model using ML, we use this persistence as a baseline and learn an ordinal neural network model that refines its results by focusing on learning weather fluctuations. The results show that the proposal outperforms persistence and other ordinal autoregressive models, especially for longer time horizon predictions and for the runway visual height variable. Copyright © 2019, The Authors. All rights reserved.

关键词： Weather forecasting

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Ranking Regions of Visual Saliency in RGB-D Content

Ranking Regions of Visual Saliency in RGB-D Content

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International Conference on 3D Imaging (IC3D)

作者： Dylan Seychell Carl J. Debono Department of Computer and Communications Engineering University of Malta

ISBN: (纸本)9781538675915;9781538675908

Effective immersion takes place when the user can relate to the 3D environment presented and interact with key objects. Efficiently predicting which objects in a scene are in the user's attention, without using additional hardware, such as eye tracking solutions, provides an opportunity for creating more immersive scenes in real time and at lower costs. This is nonetheless algorithmically challenging. In this paper, we are proposing a technique that efficiently and effectively identifies the most salient objects in a scene. We show how it accurately matches user selection within 0.04s and is over 95% faster than other saliency algorithms while also providing a ranking of the most salient segments in a scene.

关键词： Information theory Visualization Image segmentation Entropy Three-dimensional displays Indexes Two dimensional displays

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Asymmetric CNN for image super-resolution

arXiv

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arXiv 2021年

作者： Tian, Chunwei Xu, Yong Zuo, Wangmeng Lin, Chia-Wen Zhang, David The Bio-Computing Research Center Harbin Institute of Technology ShenzhenShenzhenGuangdong518055 China Shenzhen Key Laboratory of Visual Object Detection and Recognition ShenzhenGuangdong518055 China The School of Computer Science and Technology Harbin Institute of Technology HarbinHeilongjiang150001 China The Peng Cheng Laboratory ShenzhenGuangdong518055 China Shenzhen Key Laboratory of Visual Object Detection and Recognition Shenzhen Guangdong518055 China The Department of Electrical Engineering The Institute of Communications Engineering National Tsing Hua University Hsinchu Taiwan ShenzhenGuangdong518172 China The Shenzhen Institute of Artificial Intelligence and Robotics for Society Shenzhen China

Deep convolutional neural networks (CNNs) have been widely applied for low-level vision over the past five years. According to nature of different applications, designing appropriate CNN architectures is developed. However, customized architectures gather different features via treating all pixel points as equal to improve the performance of given application, which ignores the effects of local power pixel points and results in low training efficiency. In this paper, we propose an asymmetric CNN (ACNet) comprising an asymmetric block (AB), a memory enhancement block (MEB) and a high-frequency feature enhancement block (HFFEB) for image super-resolution. The AB utilizes one-dimensional asymmetric convolutions to intensify the square convolution kernels in horizontal and vertical directions for promoting the influences of local salient features for SISR. The MEB fuses all hierarchical low-frequency features from the AB via residual learning (RL) technique to resolve the long-term dependency problem and transforms obtained low-frequency features into high-frequency features. The HFFEB exploits low- and high-frequency features to obtain more robust super-resolution features and address excessive feature enhancement problem. Additionally, it also takes charge of reconstructing a high-resolution (HR) image. Extensive experiments show that our ACNet can effectively address single image super-resolution (SISR), blind SISR and blind SISR of blind noise problems. The code of the ACNet is shown at https://***/hellloxiaotian/ACNet. © 2021, CC BY-NC-ND.

关键词： Image enhancement

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