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Superpixel segmentation based on spatially constrained subspace clustering

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arXiv 2020年

作者： Li, Hua Jia, Yuheng Cong, Runmin Wu, Wenhui Kwong, Sam Chen, Chuanbo School of Software Engineering Huazhong University of Science and Technology Wuhan430074 China Department of Computer Science City University of Hong Kong Kowloon Hong Kong School of Computer Science and Engineering Southeast University Nanjing211189 China Institute of Information Science Beijing Jiaotong University Beijing100044 China Beijing Key Laboratory of Advanced Information Science and Network Technology Beijing Jiaotong University Beijing100044 China College of Electronics and Information Engineering Shenzhen University Shenzhen518060 China Department of Computer Science City University of Hong Kong Kowloon Hong Kong City University of Hong Kong Shenzhen Research Institute Shenzhen518057 China School of Software Engineering Huazhong University of Science and Technology Wuhan430074 China

Superpixel segmentation aims at dividing the input image into some representative regions containing pixels with similar and consistent intrinsic properties, without any prior knowledge about the shape and size of each superpixel. In this paper, to alleviate the limitation of superpixel segmentation applied in practical industrial tasks that detailed boundaries are difficult to be kept, we regard each representative region with independent semantic information as a subspace, and correspondingly formulate superpixel segmentation as a subspace clustering problem to preserve more detailed content boundaries. We show that a simple integration of superpixel segmentation with the conventional subspace clustering does not effectively work due to the spatial correlation of the pixels within a superpixel, which may lead to boundary confusion and segmentation error when the correlation is ignored. Consequently, we devise a spatial regularization and propose a novel convex locality-constrained subspace clustering model that is able to constrain the spatial adjacent pixels with similar attributes to be clustered into a superpixel and generate the content-aware superpixels with more detailed boundaries. Finally, the proposed model is solved by an efficient alternating direction method of multipliers (ADMM) solver. Experiments on different standard datasets demonstrate that the proposed method achieves superior performance both quantitatively and qualitatively compared with some state-of-the-art methods. © 2020, CC BY-NC-ND.

关键词： Clustering algorithms

Ray-Based Characterization of the AMPLE Model from 0.85 to 5 GHz

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arXiv 2025年

作者： Zhou, Lingyou Dong, Xin Qiu, Kehai Yu, Gang Zhang, Jie Zhang, Jiliang School of Electrical and Electronic Engineering The University of Sheffield SheffieldS10 2TN United Kingdom Ranplan Wireless Network Design Ltd. CambridgeCB23 3UY United Kingdom Department of Computer Science and Technology University of Cambridge CambridgeCB3 0FD United Kingdom College of Engineering Design and Physical Sciences Brunel University of London UxbridgeUB8 3PH United Kingdom 5G/6G Innovation Centre University of Surrey SurreyGU2 7XH United Kingdom State Key Laboratory of Synthetical Automation for Process Industries The College of Information Science and Engineering Northeastern University Shenyang110819 China National Mobile Communications Research Laboratory Southeast University Nanjing210096 China

In this paper, we characterize the adaptive multiple path loss exponent (AMPLE) radio propagation model under urban macrocell (UMa) and urban microcell (UMi) scenarios from 0.85-5 GHz using Ranplan Professional. We first enhance the original AMPLE model by introducing an additional frequency coefficient to support path loss prediction across multiple carrier frequencies. By using measurement-validated Ranplan Professional simulator, we simulate four cities and validate the simulations for further path loss model characterization. Specifically, we extract the close-in (CI) model parameters from the simulations and compare them with parameters extracted from measurements in other works. Under the ray-based model characterization, we compare the AMPLE model with the 3rd Generation Partnership Project (3GPP) path loss model, the CI model, the alpha-beta-gamma (ABG) model, and those with simulation calibrations. In addition to standard performance metrics, we introduce the prediction-measurement difference error (PMDE) to assess overall prediction alignment with measurement, and mean simulation time per data point to evaluate model complexity. The results show that the AMPLE model outperforms existing models while maintaining similar model complexity. Copyright © 2025, The Authors. All rights reserved.

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Fractional spectral graph wavelets and their applications

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arXiv 2019年

作者： Wu, Jiasong Wu, Fuzhi Yang, Qihan Kong, Youyong Liu, Xilin Zhang, Yan Senhadji, Lotfi Shu, Huazhong LIST Key Laboratory of Computer Network and Information Integration Southeast University Ministry of Education Nanjing210096 China International Joint Research Laboratory of Information Display and Visualization Southeast University Ministry of Education Nanjing210096 China INSERM U 1099 Université de Rennes 1 LTSI Rennes35000 France Centre de Recherche en Information Biomédicale Sino-francais Nanjing210096 China College of Data Science Taiyuan University of Technology Taiyuan030024 China

One of the key challenges in the area of signal processing on graphs is to design transforms and dictionaries methods to identify and exploit structure in signals on weighted graphs. In this paper, we first generalize graph Fourier transform (GFT) to graph fractional Fourier transform (GFRFT), which is then used to define a novel transform named spectral graph fractional wavelet transform (SGFRWT), which is a generalized and extended version of spectral graph wavelet transform (SGWT). A fast algorithm for SGFRWT is also derived and implemented based on Fourier series approximation. The potential applications of SGFRWT are also presented. Copyright © 2019, The Authors. All rights reserved.

关键词： Signal processing

Umbrella: Enabling ISPs to offer readily deployable and privacy-preserving DDoS prevention services

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arXiv 2019年

作者： Liu, Zhuotao Cao, Yuan Zhu, Min Ge, Wei Electrical and Computer Engineering Department University of Illinois at Urbana-Champaign UrbanaIL61801 United States Google Inc. Mountain ViewCA94043 United States College of Internet of Things Engineering Hohai University Changzhou213022 China Key Laboratory of Computer Network and Information Integration Ministry of Education Southeast University Research Institute of Applied Technologies Tsinghua University China Electrical Engineering Department Southeast University China

Defending against distributed denial of service (DDoS) attacks in the Internet is a fundamental problem. However, recent industrial interviews with over 100 security experts from more than ten industry segments indicate that DDoS problems have not been fully addressed. The reasons are twofold. On one hand, many academic proposals that are provably secure witness little real-world deployment. On the other hand, the operation model for existing DDoS-prevention service providers (e.g., Cloudflare, Akamai) is privacy invasive for large organizations (e.g., government). In this paper, we present Umbrella, a new DDoS defense mechanism enabling Internet Service Providers (ISPs) to offer readily deployable and privacy-preserving DDoS prevention services to their customers. At its core, Umbrella develops a multi-layered defense architecture to defend against a wide spectrum of DDoS attacks. In particular, the flood throttling layer stops amplification-based DDoS attacks;the congestion resolving layer, aiming to prevent sophisticated attacks that cannot be easily filtered, enforces congestion accountability to ensure that legitimate flows are guaranteed to receive their fair shares regardless of attackers' strategies;and finally the user-specific layer allows DDoS victims to enforce self-desired traffic control policies that best satisfy their business requirements. Based on Linux implementation, we demonstrate that Umbrella is capable to deal with large scale attacks involving millions of attack flows, meanwhile imposing negligible packet processing overhead. Further, our physical testbed experiments and large scale simulations prove that Umbrella is effective to mitigate various DDoS attacks. Copyright © 2019, The Authors. All rights reserved.

关键词： Denial-of-service attack

Automated Testing of Web Applications Using Combinatorial Strategies

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Journal of computer Science & Technology 2017年第1期32卷 199-210页

作者： Xiao-Fang Qi Zi-Yuan Wang Jun-Qiang Mao Peng Wang School of Computer Science and Engineering Southeast University Nanjing 211189 China Key Laboratory of Computer Network and Information Integration Ministry of Education Nanjing 211189 China School of Computer Science and Technology Nanjing University of Posts and Telecommunications Nanjing 210023 China

Recently, testing techniques based on dynamic exploration, which try to automatically exercise every possible user interface element, have been extensively used to facilitate fully testing web applications. Most of such testing tools are however not effective in reaching dynamic pages induced by form interactions due to their emphasis on handling client-side scripting. In this paper, we present a combinatorial strategy to achieve a full form test and build an automated test model. We propose an algorithm called pairwise testing with constraints （PTC） to iraplement the strategy. Our PTC algorithm uses pairwise coverage and handles the issues of semantic constraints and illegal values. We have implemented a prototype tool ComjaxTest and conducted an empirical study on five web applications. Experimental results indicate that our PTC algorithm generates less form test cases while achieving a higher coverage of dynamic pages than the general pairwise testing algorithm. Additionally, our ComjaxTest generates a relatively complete test model and then detects more faults in a reasonable amount of time, as compared with other existing tools based on dynamic exploration.

关键词： automated testing combinatorial testing web application

Dynamic community mining based on behavior prediction

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International Journal of Performability Engineering 2018年第7期14卷 1590-1599页

作者： Chen, Xiao Hu, Xinzhuan Pan, Xiao Guo, Jingfeng Network Technology Center Hebei Normal University of Science and Technology Qinhuangdao066004 China College of Economics and Management YanShan University Qinhuangdao066004 China College of Economic and Management Shijiazhuang Tiedao University Shijiazhuang050043 China College of Information Science and Engineering YanShan University Qinhuangdao066004 China Key Laboratory for Computer Virtual Technology and System Integration of Hebei Province Qinhuangdao066004 China

Dynamic network research has been a new trend in recent years. Based on the influence of vertex behavior on community structure, this paper studies signed network dynamic community mining. Firstly, the set pair connection degree is introduced to describe the relation between vertices, and the edge prediction model of signed network is proposed by taking into account the variability of the relation between vertices. Secondly, based on the prediction model, a set pair signed networks dynamic model is proposed by adding time axis T to the signed network. Then, based on the dynamic model, the evolution of signed networks and community discovering are studied. Finally, network evolution law and community stability are analyzed by using the connection trend and connection entropy in set pair theory, and the accuracy and validity of the dynamic community mining algorithm are verified by experiments. © 2018 Totem Publishers Ltd. All rights reserved.

关键词： Dynamic models

Enhancing Security of FPGA-Based Embedded Systems with Combinational Logic Binding

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Journal of computer Science & Technology 2017年第2期32卷 329-339页

作者： Ji-Liang Zhang Wei-Zheng Wang Xing-Wei Wang Zhi-Hua Xia Software College Northeastern University Shenyang 110169 China Key Laboratory of Computer Network and Information Integration (Southeast University) Ministry of Education Nanjing 210096 China Department of Computer and Communication Engineering Changsha University of Science and Technology Changsha 410014 China School of Computer and Software Nanjing University of Information Science and Technology Nanjing 210044 China

With the increasing use of field-programmable gate arrays （FPGAs） in embedded systems and many embedded applications, the failure to protect FPGA-based embedded systems from cloning attacks has brought serious losses to system developers. This paper proposes a novel combinational logic binding technique to specially protect FPGA-based embedded systems from cloning attacks and provides a pay-per-device licensing model for the FPGA market. Security analysis shows that the proposed binding scheme is robust against various types of malicious attacks. Experimental evaluations demonstrate the low overhead of the proposed technique.

关键词： cloning attack reverse engineering FPGA （field-programmable gate array） security hardware security

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IEEE Global Communications Conference

作者： Haojie Feng Yanxiang Jiang Dusit Niyato Fu-Chun Zheng Xiaohu You National Mobile Communications Research Laboratory Southeast University Nanjing China State Key Laboratory of Integrated Services Networks Xidian University Xi'an China Key Laboratory of Wireless Sensor Network & Communication Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences Shanghai China School of Computer Engineering Nanyang Technological University (NTU) Singapore School of Electronic and Information Engineering Harbin Institute of Technology Shenzhen China

ISBN: (数字)9781728109626

ISBN: (纸本)9781728109633

In this paper, the content popularity prediction problem in cache-enabled fog radio access networks (F-RANs) is investigated. In order to make the popularity prediction accurate and adaptive, we propose to learn the corresponding popularity prediction model for every content class from the preprocessed popularity series by training a simplified bidirectional long short-term memory (Bi-LSTM) network, and further use it to help build a content classifier in terms of content popularity trend in the training phase. Then, content popularity can be predicted by the right prediction model with respect to the corresponding content class in the predicting phase. Considering that it is hard to collect enough data about numerous content features through F-APs, we propose to only use the number of requests. Our proposed content popularity prediction policy offers a high prediction accuracy with low computational complexity by transferring the high complexity tasks from the predicting phase to the training phase. Simulation results show that the cache hit rate of our proposed policy approaches the optimal performance.

关键词： Predictive models Training Market research Computational modeling Machine learning Radio access networks Adaptation models

Adaptive sampling for openflow network measurement methods 17

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Adaptive sampling for openflow network measurement methods

12th International Conference on Future Internet Technologies, CFI 2017

作者： Cheng, Guang Yu, Jun School of Computer Science and Engineering Key Laboratory of Computer Network and Information Integration Southeast University Ministry of Education Nanjing211198 China

ISBN: (纸本)9781450353328

OpenFlow provides a statistics collection scheme for per-flow and aggregate metrics at a user-specified frequency. However, periodic polling for flow statistics cannot well balance the tradeofi between measurement accuracy and limited control channel bandwidth. To further discuss the resource/accuracy tradeofi, this paper extends OpenFlow protocol to add sampling action for each monitoring flow entry, and systematically sample the matching packets to infer the flow-level statistics. Although traffic sampling can somehow be error-prone, it will provide near-real-Time measurements of flow dynamics and determine its accurate polling frequency, which the polling-based approach cannot achieve. In this paper, we propose a per-flow sampling solution to instruct the controller to adaptively adjust polling frequency, then evaluate it in the context of link utilization monitoring. © 2017 Association for Computing Machinery.

关键词： Software defined networking