Publications
283 results found
Gao G, Liu CH, Chen M, et al., 2016, Cloud-Based Actor Identification With Batch-Orthogonal Local-Sensitive Hashing and Sparse Representation, IEEE Transactions on Multimedia, Vol: 18, Pages: 1749-1761, ISSN: 1941-0077
Recognizing and retrieving multimedia content withmovie/TV series actors, especially querying actor-specific videosin large scale video datasets, has attracted much attention inboth the video processing and computer vision research field.However, many existing methods have low efficiency both intraining and testing processes and also a less than satisfactoryperformance. Considering these challenges, in this paper, wepropose an efficient cloud-based actor identification approach withbatch-orthogonal local-sensitive hashing (BOLSH) and multi-taskjoint sparse representation classification. Our approach is featuredby the following: 1) videos from movie/TV series are segmented intoshots with the cloud-based shot boundary detection; 2) while facesin each shot are detected and tracked, the cloud-based BOLSHis then implemented on these faces for feature description; 3)the sparse representation is then adopted for actor identificationin each shot; and 4) finally, a simple application, actor-specificshots retrieval is realized to verify our approach. We conductextensive experiments and empirical evaluations on a large scaledataset, to demonstrate the satisfying performance of our approachconsidering both accuracy and efficiency.
He T, Gkelias A, Ma L, et al., 2016, Robust monitor placement for network tomography in dynamic networks, 35th IEEE Annual International Conference on Computer Communications (IEEE INFOCOM), Publisher: IEEE, ISSN: 1063-6692
We consider the problem of placing the minimumnumber of monitors in a dynamic network to identify additivelink metrics from path metrics measured along cycle-free pathsbetween monitors. Our goal is robust monitor placement, i.e.,the same set of monitors can maintain network identifiabilityunder topology changes. Our main contribution is a set of moni-tor placement algorithms with different performance-complexitytradeoffs that can simultaneously identify multiple topologiesoccurring during the network lifetime. In particular, we show thatthe optimal monitor placement is the solution to a generalizedhitting set problem, for which we provide a polynomial-timealgo-rithm to construct the input and a greedy algorithm to selectthemonitors with logarithmic approximation. Although the optimalplacement is NP-hard in general, we identify non-trivial specialcases that can be solved efficiently. Our secondary contributionis a dynamic triconnected decomposition algorithm to computethe input needed by the monitor placement algorithms, whichis the first such algorithm that can handle edge deletions. Ourevaluations on mobility-induced dynamic topologies verify theefficiency and the robustness of the proposed algorithms.
Ma L, He T, Swami A, et al., 2016, Network capability in localizing node failures via end-to-end path measurements, IEEE/ACM Transactions on Networking, Vol: 25, Pages: 434-450, ISSN: 1063-6692
We investigate the capability of localizing node failures in communication networks from binary states (normal/failed) of end-to-end paths. Given a set of nodes of interest, uniquely localizing failures within this set requires that different observable path states associate with different node failure events. However, this condition is difficult to test on large networks due to the need to enumerate all possible node failures. Our first contribution is a set of sufficient/necessary conditions for identifying a bounded number of failures within an arbitrary node set that can be tested in polynomial time. In addition to network topology and locations of monitors, our conditions also incorporate constraints imposed by the probing mechanism used. We consider three probing mechanisms that differ according to whether measurement paths are: (i) arbitrarily controllable; (ii) controllable but cycle-free; or (iii) uncontrollable (determined by the default routing protocol). Our second contribution is to quantify the capability of failure localization through: 1) the maximum number of failures (anywhere in the network) such that failures within a given node set can be uniquely localized and 2) the largest node set within which failures can be uniquely localized under a given bound on the total number of failures. Both measures in 1) and 2) can be converted into the functions of a per-node property, which can be computed efficiently based on the above sufficient/necessary conditions. We demonstrate how measures 1) and 2) proposed for quantifying failure localization capability can be used to evaluate the impact of various parameters, including topology, number of monitors, and probing mechanisms.
Xu P, Cumanan K, Ding Z, et al., 2016, Group Secret Key Generation in Wireless Networks: Algorithms and Rate Optimization, IEEE Transactions on Information Forensics and Security, Vol: 11, Pages: 1831-1846, ISSN: 1556-6021
This paper investigates group secret key generation problems for different types of wireless networks, by exploiting physical layer characteristics of wireless channels. A new group key generation strategy with low complexity is proposed, which combines the well-established point-to-point pairwise key generation technique, the multisegment scheme, and the one-time pad. In particular, this group key generation process is studied for three types of communication networks: 1) the three-node network; 2) the multinode ring network; and 3) the multinode mesh network. Three group key generation algorithms are developed for these communication networks, respectively. The analysis shows that the first two algorithms yield optimal group key rates, whereas the third algorithm achieves the optimal multiplexing gain. Next, for the first two types of networks, we address the time allocation problem in the channel estimation step to maximize the group key rates. This non-convex max-min time allocation problem is first reformulated into a series of geometric programming, and then, a single-condensation-method-based iterative algorithm is proposed. Numerical results are also provided to validate the performance of the proposed key generation algorithms and the time allocation algorithm.
Liu CH, Zhao J, Zhang H, et al., 2016, Energy-Efficient Event Detection by Participatory Sensing Under Budget Constraints, IEEE SYSTEMS JOURNAL, Vol: 11, Pages: 2490-2501, ISSN: 1932-8184
Dynamic event detection by using participatory sensing paradigms has received growing interests recently, where detection tasks are assigned to smart-device users who can potentially collect needed sensory data from device-equipped sensors. Typical applications include, but are not limited to, noise and air pollution detections, people gathering, even disaster prediction. Given this problem, although many existing centralized solutions are effective and widely used, they usually cause heavy communication overhead. Thus, it is strongly desired to design distributed solutions to reduce energy consumption, while achieving a high level of detection accuracy with limited sensing task budget. In this paper, we first present two novel centralized detection algorithms as the performance benchmark, which make use of the Minimum Cut theory and support vector machine (SVM)-based pattern recognition techniques. Then, we introduce a novel distributed and energy-efficient event detection framework under task budget constraint, where we formulate an optimization problem and derive an optimal utility function. Finally, based on a real trace-driven data set in an urban area of Beijing, extensive simulation results demonstrate the effectiveness of our proposed algorithms.
Wang W, Gao H, Liu CH, et al., 2016, Credible and energy-aware participant selection with limited task budget for mobile crowd sensing, Ad Hoc Networks, Vol: 43, Pages: 56-70, ISSN: 1570-8713
Crowd sensing campaigns encourage ordinary people to collect and share sensing data by using their carried smart devices. However, new challenges that must be faced have arisen. One of them is how to allocate tasks to the most appropriate participants when considering their different incentive requirements and credibility, in order to best satisfy the quality-of-information (QoI) requirements of multiple concurrent tasks, with different, and limited budget constraints. Another challenge is how to maximize participants’ rewards to encourage them to contribute sensing data continuously. To this end, in this paper, we first propose a crowd sensing system, that aims to address the above two challenges, where the system considers the benefits of both platform and participants. Then, a participant reputation definition and update method is proposed, that takes participant’s willingness and contributed data quality into consideration. Last, we introduce two metrics called “QoI satisfaction” and “Difficulty of Task (DoT)”. The former quantifies how much collected sensing data can satisfy the multi-dimensional task’s QoI requirements in terms of data quality, granularity and quantity, and the later aids participants to choose proper tasks to maximize their rewards. Finally, we compare our proposed scheme with existing methods via extensive simulations based on a real dataset. Extensive simulation results well justify the effectiveness and robustness of our approach.
Yueruer O, Liu CH, Sheng Z, et al., 2016, Context-Awareness for Mobile Sensing: A Survey and Future Directions, IEEE Communications Surveys and Tutorials, Vol: 18, Pages: 68-93, ISSN: 1553-877X
The evolution of smartphones together with increasingcomputational power has empowered developers to createinnovative context-aware applications for recognizing user-relatedsocial and cognitive activities in any situation and at any location.The existence and awareness of the context provide the capabilityof being conscious of physical environments or situations aroundmobile device users. This allows network services to respondproactively and intelligently based on such awareness. The keyidea behind context-aware applications is to encourage users tocollect, analyze, and share local sensory knowledge in the purposefor a large-scale community use by creating a smart network. Thedesired network is capable of making autonomous logical decisionsto actuate environmental objects and also assist individuals.However, many open challenges remain, which are mostly arisenbecause the middleware services provided in mobile devices havelimited resources in terms of power, memory, and bandwidth.Thus, it becomes critically important to study how the drawbackscan be elaborated and resolved and, at the same time, betterunderstand the opportunities for the research community to contributeto the context-awareness. To this end, this paper surveysthe literature over the period of 1991–2014 from the emergingconcepts to applications of context-awareness in mobile platformsby providing up-to-date research and future research directions.Moreover, it points out the challenges faced in this regard andenlightens them by proposing possible solutions.
Machen A, Wang S, Leung KK, et al., 2016, Migrating Running Applications Across Mobile Edge Clouds, 22nd Annual International Conference on Mobile Computing and Networking (MobiCom), Publisher: ASSOC COMPUTING MACHINERY, Pages: 435-436
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- Citations: 28
Liu CH, Fan J, Hui P, et al., 2015, Toward QoI and Energy Efficiency in Participatory Crowdsourcing, IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY, Vol: 64, Pages: 4684-4700, ISSN: 0018-9545
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- Citations: 35
Rossi GV, Leung KK, Gkelias A, 2015, Density-based optimal transmission for throughput enhancement in wehicular ad-hoc networks, IEEE International Conference on Communications (ICC), Publisher: IEEE, Pages: 6571-6576, ISSN: 1550-3607
Vehicular ad-hoc networks (VANETs) have received a lot of research and industrial attention, including the approval of the IEEE 802.11p standard. However, resource allocation in the standard still makes use of the traditional mechanisms (e.g., carrier sensing) without exploiting the unique characteristics of VANETs. This provides the motivation for this work. As a first step toward the goal and by considering vehicle density, this paper investigates how transmission probability can be determined to optimise throughput of VANETs. A challenging design issue of VANETs is to deal with node (vehicle) mobility, which causes various vehicular densities within the same network and consequently influences the connectivity and capacity of the network. This work shows that it is indeed possible to follow the dynamics of a network and consequently adapt the transmission probability at the MAC layer to reduce the interference and maximise the single-hop throughput between adjacent nodes. By exploiting the characteristics of VANETs, we introduce approximations in order to derive closed-form expressions of the network throughput and other performance metrics in terms of transmission probability, which would otherwise be impossible. Our extensive simulations validate the approximations and the proposed analytical model thus can serve as a promising tool to improve VANETs performance. For example, the optimal transmission probability can be used to develop efficient MAC protocols using vehicle density estimation in VANETs for our future work.
Ma L, He T, Swami A, et al., 2015, On optimal monitor placement for localizing node failures via network tomography, PERFORMANCE EVALUATION, Vol: 91, Pages: 16-37, ISSN: 0166-5316
Urgaonkar R, Wang S, He T, et al., 2015, Dynamic service migration and workload scheduling in edge-clouds, PERFORMANCE EVALUATION, Vol: 91, Pages: 205-228, ISSN: 0166-5316
Sheng Z, Fan J, Liu CH, et al., 2015, Energy-Efficient Relay Selection for Cooperative Relaying in Wireless Multimedia Networks, IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY, Vol: 64, Pages: 1156-1170, ISSN: 0018-9545
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- Citations: 55
Wang S, Urgaonkar R, Zafer M, et al., 2015, Dynamic Service Migration in Mobile Edge-Clouds, IFIP Networking Conference IFIP Networking, Publisher: IEEE
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- Citations: 78
Liu CH, Zhang Z, Huang Y, et al., 2015, Distributed and Real-Time Query Framework for Processing Participatory Sensing Data Streams, 2015 IEEE 17th International Conference on High Performance Computing and Communications (HPCC), Publisher: IEEE, Pages: 248-253, ISSN: 2576-3504
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- Citations: 2
Wang S, Urgaonkar R, Chan K, et al., 2015, Dynamic Service Placement for Mobile Micro-Clouds with Predicted Future Costs, IEEE International Conference on Communications (ICC), Publisher: IEEE, Pages: 5504-5510, ISSN: 1550-3607
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- Citations: 21
Zhao J, Liu CH, Chen M, et al., 2015, Energy-Efficient Dynamic Event Detection by Participatory Sensing, IEEE International Conference on Communications (ICC), Publisher: IEEE, Pages: 3180-3185, ISSN: 1550-3607
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- Citations: 2
Cong K, Leung KK, 2015, Localization Accuracy of Classification Techniques for Wi-Fi Environments, IEEE International Conference on Digital Signal Processing (DSP), Publisher: IEEE, Pages: 1161-1165
Tychogiorgos G, Gkelias A, Leung KK, 2015, Distributed Network Resource Allocation for Multi-Tiered Multimedia Applications, 34th IEEE Conference on Computer Communications (INFOCOM), Publisher: IEEE, ISSN: 0743-166X
Gao H, Liu CH, Wang W, et al., 2015, A Survey of Incentive Mechanisms for Participatory Sensing, IEEE COMMUNICATIONS SURVEYS AND TUTORIALS, Vol: 17, Pages: 918-943
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- Citations: 129
Wang S, Chan K, Urgaonkar R, et al., 2015, Emulation-Based Study of Dynamic Service Placement in Mobile Micro-Clouds, 34th IEEE Annual Military Communications Conference (MILCOM) on Leveraging Technology - The Joint Imperative, Publisher: IEEE, Pages: 1046-1051, ISSN: 2155-7578
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- Citations: 14
Liu CH, Fan J, Branch JW, et al., 2014, Toward Qol and Energy-Efficiency in Internet-of-Things Sensory Environments, IEEE TRANSACTIONS ON EMERGING TOPICS IN COMPUTING, Vol: 2, Pages: 473-487, ISSN: 2168-6750
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- Citations: 65
Wang S, Urgaonkar R, He T, et al., 2014, Mobility-induced service migration in mobile micro-clouds, Military Communications Conference (MILCOM), 2014 IEEE, Publisher: IEEE, Pages: 835-840
Mobile micro-cloud is an emerging technology indistributed computing, which is aimed at providing seamlesscomputing/data access to the edge of the network when acentralized service may suffer from poor connectivity and longlatency. Different from the traditional cloud, a mobile micro-cloudis smaller and deployed closer to users, typically attached to acellular basestation or wireless network access point. Due to therelatively small coverage area of each basestation or access point,when a user moves across areas covered by different basestationsor access points which are attached to different micro-clouds,issues of service performance and service migration becomeimportant. In this paper, we consider such migration issues. Wemodel the general problem as a Markov decision process (MDP),and show that, in the special case where the mobile user followsa one-dimensional asymmetric random walk mobility model, theoptimal policy for service migration is a threshold policy. Weobtain the analytical solution for the cost resulting from arbitrarythresholds, and then propose an algorithm for finding the optimalthresholds. The proposed algorithm is more efficient than standardmechanisms for solving MDPs.
Ma L, He T, Leung KK, et al., 2014, Inferring link metrics from end-to-end path measurements: Identifiability and monitor placement, IEEE ACM Transactions on Networking, Vol: 22, Pages: 1351-1368, ISSN: 1063-6692
We investigate the problem of identifying individual link metrics in a communication network from end-to-end path measurements, under the assumption that link metrics are additive and constant. To uniquely identify the link metrics, the number of linearly independent measurement paths must equal the number of links. Our contribution is to characterize this condition in terms of the network topology and the number/placement of monitors, under the constraint that measurement paths must be cycle-free. Our main results are: 1) it is generally impossible to identify all the link metrics by using two monitors; 2) nevertheless, metrics of all the interior links not incident to any monitor are identifiable by two monitors if the topology satisfies a set of necessary and sufficient connectivity conditions; 3) these conditions naturally extend to a necessary and sufficient condition for identifying all the link metrics using three or more monitors. We show that these conditions not only facilitate efficient identifiability tests, but also enable an efficient algorithm to place the minimum number of monitors in order to identify all link metrics. Our evaluations on both random and real topologies show that the proposed algorithm achieves identifiability using a much smaller number of monitors than a baseline solution.
Alayev Y, Chen F, Hou Y, et al., 2014, Throughput Maximization in Mobile WSN Scheduling With Power Control and Rate Selection, IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, Vol: 13, Pages: 4066-4079, ISSN: 1536-1276
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- Citations: 14
Tychogiorgos G, Leung KK, 2014, Optimization-based resource allocation in communication networks, COMPUTER NETWORKS, Vol: 66, Pages: 32-45, ISSN: 1389-1286
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- Citations: 26
Ding Z, Leung KK, Poor HV, 2014, Interference masking for secure wireless broadcast communications, IET COMMUNICATIONS, Vol: 8, Pages: 1184-1197, ISSN: 1751-8628
Cumanan K, Ding Z, Sharif B, et al., 2014, Secrecy Rate Optimizations for a MIMO Secrecy Channel With a Multiple-Antenna Eavesdropper, IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY, Vol: 63, Pages: 1678-1690, ISSN: 0018-9545
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- Citations: 123
Liu CH, Leung KK, Gkelias A, 2014, A Generic Admission-Control Methodology for Packet Networks, IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, Vol: 13, Pages: 604-617, ISSN: 1536-1276
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- Citations: 14
Xu P, Ding Z, Dai X, et al., 2014, A General Framework of Wiretap Channel With Helping Interference and State Information, IEEE TRANSACTIONS ON INFORMATION FORENSICS AND SECURITY, Vol: 9, Pages: 182-195, ISSN: 1556-6013
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- Citations: 17
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