Tsinghua Science and Technology

  • Guest Editorial: Special Issue on Internet of Things

    Zhipeng Cai;Anu Bourgeois;Weitian Tong;

    <正>Internet of Things(IoT)is a new paradigm that the ubiquitous smart objects,such as devices,vehicles,buildings,etc.,interact and exchange data through emerging wireless technology with the intention of improving people’s quality of lives in variety areas,such as transportation,manufacturing industry,health care industry,etc:Besides benefits,this envisioned

    2017年04期 v.22 343-344页 [查看摘要][在线阅读][下载 405K]
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  • Robust and Passive Motion Detection with COTS WiFi Devices

    Hai Zhu;Fu Xiao;Lijuan Sun;Xiaohui Xie;Panlong Yang;Ruchuan Wang;

    Device-free Passive(DfP) detection has received increasing attention for its ability to support various pervasive applications. Instead of relying on variable Received Signal Strength(RSS), most recent studies rely on finer-grained Channel State Information(CSI). However, existing methods have some limitations, in that they are effective only in the Line-Of-Sight(LOS) or for more than one moving individual. In this paper, we analyze the human motion effect on CSI and propose a novel scheme for Robust Passive Motion Detection(R-PMD). Since traditional low-pass filtering has a number of limitations with respect to data denoising, we adopt a novel Principal Component Analysis(PCA)-based filtering technique to capture the representative signals of human motion and extract the variance profile as the sensitive metric for human detection. In addition, existing schemes simply aggregate CSI values over all the antennas in MIMO systems. Instead, we investigate the sensing quality of each antenna and aggregate the best combination of antennas to achieve more accurate and robust detection. The R-PMD prototype uses off-the-shelf WiFi devices and the experimental results demonstrate that R-PMD achieves an average detection rate of 96.33% with a false alarm rate of 3.67%.

    2017年04期 v.22 345-359页 [查看摘要][在线阅读][下载 1436K]
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  • On the Performance of the Energy Detector Subject to Impulsive Noise in κ-μ, α-μ, and η-μ Fading Channels

    Jos V.M.Cardoso;Wamberto J.L.Queiroz;Hang Liu;Marcelo S.Alencar;

    This paper presents a unified theoretical analysis of the energy detection of Gaussian and M-PSK signals in κ-μ,α-μ,and η-μ fading channels at the output of an energy detector subject to impulsive noise(Bernoulli-Gaussian model). As a result, novel, simple, and accurately approximated expressions for the probability of detection are derived. More precisely, the generalized Gauss-Laguerre quadrature is applied to approximate the probability of detection as a simple finite sum. Monte Carlo simulations corroborate the accuracy and precision of the derived approximations. The results are further extended to cooperative energy detection with hard decision combining information.

    2017年04期 v.22 360-367页 [查看摘要][在线阅读][下载 2569K]
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  • A Novel Analysis of Delay and Power Consumption for Polling Schemes in the IoT

    Li Feng;Jiguo Yu;Feng Zhao;Honglu Jiang;

    In the Internet of Things(IoT), various battery-powered wireless devices are connected to collect and exchange data, and typical traffic is periodic and heterogeneous. Polling with power management is a very promising technique that can be used for communication among these devices in the IoT. In this paper, we propose a novel and scalable model to study the delay and the power consumption performance for polling schemes with power management under heterogeneous settings(particularly the heterogeneous sleeping interval). In our model,by introducing the concept of virtual polling interval, we successfully convert the considered energy-efficient polling scheme into an equivalent purely-limited vacation system. Thus, we can easily evaluate the mean and variance of the delay and the power consumption by applying existing queueing formulae, without developing a new theoretical model as required in previous works. Extensive simulations show that our analytical results are very accurate for both homogeneous and heterogeneous settings.

    2017年04期 v.22 368-378页 [查看摘要][在线阅读][下载 1168K]
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  • IoT-Based Cost Saving Offloading System for Cellular Networks

    Zhuojun Duan;Mingyuan Yan;Qilong Han;Lijie Li;Yingshu Li;

    Nowadays, with the new techniques available in hardware and software, data requests generated by applications of mobile devices have grown explosively. The large amount of data requests and their responses lead to heavy traffic in cellular networks. To alleviate the transmission workload, offloading techniques have been proposed, where a cellular network distributes some popular data items to other wireless networks, so that users can directly download these data items from the wireless network around them instead of the cellular network.In this paper, we design a Cost Saving Offloading System(CoSOS), where the Internet of Things(IoT) is used to undertake partial data traffic and save more bandwidth for the cellular network. Two types of algorithms are proposed to handle the popular data items distribution among users. The experimental results show that CoSOS is useful in saving bandwidth and decreasing the cost for cellular networks.

    2017年04期 v.22 379-388页 [查看摘要][在线阅读][下载 743K]
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  • Optimization-Based Fragmental Transmission Method for Video Data in Opportunistic Networks

    Peng Li;Xiaoming Wang;Junling Lu;Lichen Zhang;Zaobo He;

    Multimedia data have become popularly transmitted content in opportunistic networks. A large amount of video data easily leads to a low delivery ratio. Breaking up these big data into small pieces or fragments is a reasonable option. The size of the fragments is critical to transmission efficiency and should be adaptable to the communication capability of a network. We propose a novel communication capacity calculation model of opportunistic network based on the classical random direction mobile model, define the restrain facts model of overhead, and present an optimal fragment size algorithm. We also design and evaluate the methods and algorithms with video data fragments disseminated in a simulated environment. Experiment results verified the effectiveness of the network capability and the optimal fragment methods.

    2017年04期 v.22 389-399页 [查看摘要][在线阅读][下载 622K]
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  • Route Guardian: Constructing Secure Routing Paths in Software-Defined Networking

    Mengmeng Wang;Jianwei Liu;Jian Mao;Haosu Cheng;Jie Chen;Chan Qi;

    Software-Defined Networking(SDN) decouples the control plane and the data plane in network switches and routers, which enables the rapid innovation and optimization of routing and switching configurations. However,traditional routing mechanisms in SDN, based on the Dijkstra shortest path, do not take the capacity of nodes into account, which may lead to network congestion. Moreover, security resource utilization in SDN is inefficient and is not addressed by existing routing algorithms. In this paper, we propose Route Guardian, a reliable securityoriented SDN routing mechanism, which considers the capabilities of SDN switch nodes combined with a Network Security Virtualization framework. Our scheme employs the distributed network security devices effectively to ensure analysis of abnormal traffic and malicious node isolation. Furthermore, Route Guardian supports dynamic routing reconfiguration according to the latest network status. We prototyped Route Guardian and conducted theoretical analysis and performance evaluation. Our results demonstrate that this approach can effectively use the existing security devices and mechanisms in SDN.

    2017年04期 v.22 400-412页 [查看摘要][在线阅读][下载 2253K]
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  • Distributed Algorithms for Event Reporting in Mobile-Sink WSNs for Internet of Things

    Catalina Aranzazu-Suescun;Mihaela Cardei;

    Wireless Sensor Networks(WSNs) have many applications, such as climate monitoring systems, fire detection, smart homes, and smart cities. It is expected that WSNs will be integrated into the Internet of Things(IoT)and participate in various tasks. WSNs play an important role monitoring and reporting environment information and collecting surrounding context. In this paper we consider a WSN deployed for an application such as environment monitoring, and a mobile sink which acts as the gateway between the Internet and the WSN. Data gathering is a challenging problem in WSNs and in the IoT because the information has to be available quickly and effectively without delays and redundancies. In this paper we propose several distributed algorithms for composite event detection and reporting to a mobile sink. Once data is collected by the sink, it can be shared using the IoT infrastructure. We analyze the performance of our algorithms using WSNet simulator, which is specially designed for event-based WSNs. We measure various metrics such as average residual energy, percentage of composite events processed successfully at the sink, and the average number of hops to reach the sink.

    2017年04期 v.22 413-426页 [查看摘要][在线阅读][下载 14345K]
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  • Detecting Isolate Safe Areas in Wireless Sensor Monitoring Systems

    Chunyu Ai;Frank Haizhon Li;Kejia Zhang;

    Wireless sensors are deployed widely to monitor space, emergent events, and disasters. Collected realtime sensory data are precious for completing rescue missions quickly and efficiently. Detecting isolate safe areas is significant for various applications of event and disaster monitoring since valuable real-time information can be provided for the rescue crew to save persons who are trapped in isolate safe areas. We propose a centralized method to detect isolate safe areas via discovering holes in event areas. In order to shorten the detection delay, a distributed isolate safe area detection method is studied. The distributed method detects isolate safe areas during the process of event detection. Moreover, detecting isolate safe areas in a building is addressed particularly since the regular detecting method is not applicable. Our simulation results show that the distributed method can detect all isolate safe areas in an acceptable short delay.

    2017年04期 v.22 427-436页 [查看摘要][在线阅读][下载 627K]
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  • On the Security of Information Dissemination in the Internet-of-Vehicles

    Danda B.Rawat;Moses Garuba;Lei Chen;Qing Yang;

    Internet of Vehicles(IoV) is regarded as an emerging paradigm for connected vehicles to exchange their information with other vehicles using vehicle-to-vehicle(V2V) communications by forming a vehicular ad hoc networks(VANETs), with roadside units using vehicle-to-roadside(V2R) communications. IoV offers several benefits such as road safety, traffic efficiency, and infotainment by forwarding up-to-date traffic information about upcoming traffic. For instance, IoV is regarded as a technology that could help reduce the number of deaths caused by road accidents, and reduce fuel costs and travel time on the road. Vehicles could rapidly learn about the road condition and promptly respond and notify drivers for making informed decisions. However, malicious users in IoV may mislead the whole communications and create chaos on the road. Data falsification attack is one of the main security issues in IoV where vehicles rely on information received from other peers/vehicles. In this paper,we present data falsification attack detection using hashes for enhancing network security and performance by adapting contention window size to forward accurate information to the neighboring vehicles in a timely manner(to improve throughput while reducing end-to-end delay). We also present clustering approach to reduce travel time in case of traffic congestion. Performance of the proposed approach is evaluated using numerical results obtained from simulations. We found that the proposed adaptive approach prevents IoV from data falsification attacks and provides higher throughput with lower delay.

    2017年04期 v.22 437-445页 [查看摘要][在线阅读][下载 2570K]
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  • Call for Papers Special Issue on Cloud Computing and Big Data Applications

    <正>The publication of Tsinghua Science and Technology was started in 1996.Since then,it has been an international academic journal sponsored by Tsinghua University and published bimonthly.This journal aims at presenting the state-of-art scientific achievements in computer science and other IT fields.From 2012,the journal enters into IEEE

    2017年04期 v.22 446页 [查看摘要][在线阅读][下载 61K]
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  • Information for Contributors

    <正>Tsinghua Science and Technology(Tsinghua Sci Technol),an academic journal sponsored by Tsinghua University,is published bimonthly.This journal aims at presenting the up-to-date scientific achievements with high creativity and great significance in computer and electronic engineering.Contributions all over the world are welcome.Tsinghua Sci Technol is indexed by SCI,Engineering index(Ei,USA),INSPEC,SA,Cambridge Abstract,and

    2017年04期 v.22 447页 [查看摘要][在线阅读][下载 410K]
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