Sanglu Lu

Nanjing University, Nan-ching, Jiangsu Sheng, China

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Publications (147)80.5 Total impact

  • Lei Xie · Qun Li · Chuyu Wang · Xi Chen · Sanglu Lu
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    ABSTRACT: In this paper, we show the first comprehensive experimental study on mobile RFID reading performance based on a relatively large number of tags. By making a number of observations regarding the tag reading performance, we build a model to depict how various parameters affect the reading performance. Through our model, we have designed very efficient algorithms to maximize the time-efficiency and energy-efficiency by adjusting the reader’s power and moving speed. Our experiments show that our algorithms can reduce the total scanning time by 50% and the total energy consumption by 83% compared to the prior solutions.
    No preview · Article · Nov 2015 · IEEE Transactions on Mobile Computing
  • Hao Wu · Zhuzhong Qian · Xin Li · Sanglu Lu
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    ABSTRACT: Flow scheduling is one of the primary issues in data centers. The efficiency of flow scheduling affects the user experience significantly, since the service latency is determined by the flow completion time (FCT). Current transport protocols are based on the Processor Sharing (PS) policy by dividing the link bandwidth equally. As short flows may be blocked by long flows under PS policy, these protocols could not meet latency requirements. The Shortest Remaining Processing Time (SRPT) policy provides a near-optimal solution in term of reducing average FCT. However, this flow scheduling policy may cause long flows suffering unfair delays. In this paper, we propose MERP (Minimizing Expansion Ratio Protocol) for flow scheduling, which aims to navigate the tradeoff between fairness and the average FCT. We propose expansion ratio as a new metric to describe the gap between reality and ideal in terms of acquired link resources by a flow. Larger expansion ratio indicates that the flow obtains fewer bottleneck link resources. We strive to make the flow scheduling relatively fair by reducing the largest expansion ratio of all the flows. And we further demonstrate that reducing expansion ratio is more reasonable than reducing average FCT for services with the Partition/Aggregate pattern. And to meet the scalability requirements, we implement distributed MERP through flow preemption and explicit rate control. The experiments indicate that MERP could significantly reduce the completion time for 99.9th percentile flows under high load.
    No preview · Article · Apr 2015
  • Ruiqing Chi · Zhuzhong Qian · Sanglu Lu
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    ABSTRACT: With the rapid development of virtualization techniques, modern data centers move into a new era of cloud in recent years. Despite numerous advantages such as high resource utilization and rapid service scalability, current virtualization techniques don't guarantee perfect performance isolation among virtual machines sharing the physical machine, which may lead to unstable and unpredictable user-perceived application performance in clouds. Therefore, understanding and modeling performance interference among collocated applications is of utmost importance. However, the hypervisor and guest OSes usually run independent resource schedulers and are invisible into each other, thereby making accurately characterizing performance interference a non-trivial work. In this paper, we first present a comprehensive experimental study on performance interference of different combinations of benchmarks, observing that virtual CPU floating overhead between multiple physical CPUs, and VMEXITs, i.e., the control transitions between the hypervisor and VMs, constitute the key source of performance interference. In order to characterize the performance interference effects, we measure both the application-level and VM-level characteristics from the collocated applications and then build a novel interference prediction framework based on kernel canonical correlation analysis. Our evaluations first show the practicability of KCCA in finding reliable correlation, and further confirm the high accuracy and great applicability of our interference model with a low prediction error of no more than 7.9%.
    No preview · Article · Apr 2015
  • Sheng Zhang · Jie Wu · Zhuzhong Qian · Sanglu Lu
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    ABSTRACT: Offloading cellular traffic through mobile social networks has arisen as a promising way for relieving cellular networks. Prior studies mainly focused on caching data in a number of pre-selected helpers. However, such a strategy would fail when mobile users enter and leave the target area over time. In this paper, we examine the research decisions and design tradeoffs that arise when offloading cellular traffic in such a dynamic area of interest, referred to as a MobiArea, and we design an offloading framework, MobiCache, for maximizing cellular operators’ revenues and minimizing the overhead imposed on mobile devices. On the user side, we propose a content floating-based cooperative caching strategy that caches data in geographical floating circles, instead of selected helpers in previous studies, to cope with the dynamics. A geographical routing scheme is designed for delivering data and queries towards floating circles. We also develop a cache replacement scheme to improve caching cost-effectiveness inside floating circles. On the operator side, query history and feedback are maintained for cellular operators to optimize framework parameters that maximize their revenues. Extensive trace-driven simulations show that, compared with a state-of-the-art scheme, MobiCache offloads up to 52% more traffic with 15% shorter delay and 6% less forwarding cost.
    No preview · Article · Mar 2015 · Computer Networks
  • Wenzhong Li · Yanchao Zhao · Sanglu Lu · Daoxu Chen
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    ABSTRACT: While mobility is the inherent cause of resource poverty and low connectivity in wireless environment, it also enables the opportunity for surrounding sensing, therefor providing mobilityaugmented cloud service becomes the key challenge for the emerging paradigm of Mobile Cloud Computing (MCC). This article provides an overview of the mechanisms and open issues for mobility-augmented service provisioning in MCC. We first outline the concept, system architecture, and taxonomy of research issues. Then we introduce three key mechanisms with respect to mobility augmentation, heterogeneous network convergence and mobile service provisioning. Moreover, we discuss the open challenges to reveal the future direction of MCC.
    No preview · Article · Mar 2015 · IEEE Communications Magazine
  • Hao Ji · Lei Xie · Chuyu Wang · Yafeng Yin · Sanglu Lu
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    ABSTRACT: As a supporting technology for most pervasive applications, indoor localization and navigation has attracted extensive attention in recent years. Conventional solutions mainly leverage techniques like WiFi, cellular network etc. to effectively locate the user for indoor localization and navigation. In this paper, we investigate the problem of indoor navigation by using the RFID-based delay tolerant network. Different from the previous work, we aim to efficiently locate and navigate to a specified mobile user who is continuously moving within the indoor environment. As the low-cost RFID tags are widely deployed inside the indoor environment and acting as landmarks, the mobile users can actively interrogate the surrounding tags with devices like smart phones and leave messages or traces to the tags. These messages or traces can be carried and forwarded to more tags by other mobile users. In this way, the RFID-based infrastructure forms a delay tolerant network. By using the crowd-sourcing technology in RFID-based delay tolerant network, we respectively propose a framework, namely CrowdSensing, to schedule the tasks and manage the resources in the network. We further propose a navigation algorithm to locate and navigate to the moving target. We verify the performance of proposed framework and navigation algorithm on mobility model built on real-world human traceset. Experiment results show that our solution can efficiently reduce the average searching time for indoor navigation.
    No preview · Article · Mar 2015 · Journal of Network and Computer Applications
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    ABSTRACT: With the increasing number of location-dependent applications, positioning and tracking a mobile device becomes more and more important to enable pervasive and context-aware service. While extensive research has been performed in physical localization and logical localization for satellite, GSM and WiFi communication networks where fixed reference points are densely-deployed, positioning and tracking techniques in a sparse disruption tolerant network (DTN) have not been well addressed. In this paper, we propose a decentralized cooperative method called PulseCounting for DTN localization and a probabilistic tracking method called ProbTracking to confront this challenge. PulseCounting evaluates the user walking steps and movement orientations using accelerometer and electronic compass equipped in cellphones. It estimates user location by accumulating the walking segments, and improves the estimation accuracy by exploiting the encounters of mobile nodes. Several methods to refine the location estimation are discussed, which include the adjustment of trajectory based on reference points and the mutual refinement of location estimation for encountering nodes based on maximum-likelihood. To track user movement, the proposed ProbTracking method uses Markov chain to describe movement patterns and determines the most possible user walking trajectories without full record of user locations. We implemented the positioning and tracking system in Android phones and deployed a testbed in the campus of Nanjing University. Extensive experiments are conducted to evaluate the effectiveness and accuracy of the proposed methods, which show an average deviation of 9m in our system compared to GPS.
    No preview · Article · Feb 2015 · IEEE Transactions on Parallel and Distributed Systems
  • Sheng Zhang · Zhuzhong Qian · Zhaoyi Luo · Jie Wu · Sanglu Lu

    No preview · Article · Jan 2015 · IEEE Transactions on Parallel and Distributed Systems
  • Yafeng Yin · Lei Xie · Jie Wu · Sanglu Lu

    No preview · Article · Jan 2015 · IEEE Transactions on Computers
  • Bin Tang · Shenghao Yang · Baoliu Ye · Song Guo · Sanglu Lu

    No preview · Article · Jan 2015 · IEEE Transactions on Computers
  • Tao Huang · Baoliu Ye · Song Guo · Sanglu Lu
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    ABSTRACT: The research breakthrough on the hardware implementation of wireless full-duplex transmission has attracted significant interests on building full-duplex wireless networks in recent years. However, due to the asymmetry of real traffic flows, it is challenging to improve the network performance by effectively utilizing the full-duplex capacity. In this paper, we investigate the transmission delay minimization problem of full-duplex WLANs under ad-hoc mode. We first derive a lower bound of the total transmission delay and then propose a relay-based cooperative schedule scheme named CR-Mechanism, via exploiting eligible full-duplex communication opportunities. Our theoretical analysis shows that it achieves such lower bound with a polynomial-time complexity. Furthermore, the closed-form expressions of the expectation of totaly delay, time saving and transmission cost of CR-Mechanism are also derived. The extensive experimental results confirm that CR-Mechanism is an optimal scheduling algorithm with better performance than conventional mechanisms under different traffic models.
    No preview · Article · Nov 2014 · Journal of Network and Computer Applications
  • Chen Wang · Baoliu Ye · Xiaoliang Wang · Song Guo · Sanglu Lu
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    ABSTRACT: Many studies have presented the order sense results of information transmission capacity and packet delivery delay in mobile ad hoc networks (MANETs). To achieve the fundamental understanding of MANETs, we focus on deriving the closed-form expressions of the network capacity and end-to-end delay. A MANET with the generalized correlated mobility model is considered in this paper, where the mobility of nodes clustered in one group is confined within a specified area, and multiple groups move uniformly across the network. We also leverage limited packet redundancy to speed up the packet transmission, i.e., each source node is allowed to distribute at most f copies of each packet in its delivery process. Specifically, we first propose an effective multi-hop scheduling-routing scheme under the correlated mobility model, and then develop the closed-form expressions of both per node throughput capacity and expected end-to-end delay. We further explore the tradeoff between throughput capacity and packet delay by using packet redundancy f. The simulation studies validate our theoretical results.
    No preview · Article · Nov 2014 · IEEE Transactions on Parallel and Distributed Systems
  • Source
    Qinhui Wang · Baoliu Ye · Sanglu Lu · Song Guo
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    ABSTRACT: In cognitive radio networks (CRNs), a wireless user with primary access right on a channel (called primary user) has prioritized access to the channel and the user with secondary access right (called secondary user) can use the channel when the primary user is idle. Spectrum auction has emerged as a promising approach to address the access allocation problem in CRNs. A significant challenge in designing such auction is providing truthfulness to avoid market manipulation. In most previous work, the primary access rights on channels are pre-determined before the auction and bidders can only compete for the secondary access rights. However, a user's requirement on spectrum access rights relies on their QoS demands. Therefore, it is much desirable to allocate spectrum access rights on the basis of QoS demands as well as to exploit the resulting spatial spectrum reuse opportunities. To solve this problem, we propose TRUMP, a truthful spectrum auction mechanism, by taking into consideration both QoS demands and spectrum spatial reuse, which can drastically improve spectrum utilization. The theoretical analysis proves that TRUMP achieves truthfulness and individual rationality with polynomial-time complexity. Our extensive simulation results show that our proposals outperform previous work in terms of both social welfare and spectrum utilization.
    Full-text · Article · Oct 2014 · IEEE Transactions on Parallel and Distributed Systems

  • No preview · Article · Aug 2014
  • Yafeng Yin · Lei Xie · Sanglu Lu · Daoxu Chen
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    ABSTRACT: With the rapid proliferation of RFID technologies, RFID has been introduced to the applications like safety inspection and warehouse management. Conventionally a number of deployment rules are specified for these applications. This paper studies a practically important problem of rule checking over RFID tags, i.e., checking whether the specified rules are satisfied according to the RFID tags within the monitoring area. This rule checking function may need to be executed frequently over a large number of tags and therefore should be made efficient in terms of execution time. Aiming to achieve time efficiency, we respectively propose two protocols, CRCP and ECRCP. CRCP works based on collision detection, while ECRCP combines the collision detection and the logical features of the rules. Simulation results indicate that our protocols achieve much better performance than other solutions in terms of time efficiency.
    No preview · Conference Paper · Aug 2014
  • Sheng Zhang · Zhuzhong Qian · Jie Wu · Sanglu Lu
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    ABSTRACT: Virtual networks that allow tenants to explicitly specify their computing as well as networking resources are recently proposed to be better interfaces between cloud providers and tenants. Many virtual networks have time-varying resource demands, as evidenced in prior studies [1-3]. New opportunities emerge when such variation is exploited. In this paper, we design a novel resource demand model for tenants to flexibly trade off between application performance and cost, and propose a work-conserving allocation algorithm, WCA, for deploying virtual networks with time-varying resource demands. WCA places virtual nodes in a first-fit fashion, and places virtual links through path-splitting. In each physical node or link, by opportunistically sharing physical resources among multiple variable parts of resource demands, physical utilization can be improved, and more virtual networks can be deployed concurrently. Our evaluation results show that WCA achieves a 4% higher physical resource utilization and rejects 18% less virtual network requests than a state-of-the-art algorithm [4].
    No preview · Conference Paper · Aug 2014
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    ABSTRACT: Motivated by various applications in mobile ad-hoc networks (MANETs) that require nodes to share their individual information to each other, we study the multi-message dissemination problem in a MANET, which is to distribute multiple messages to all mobile nodes in the network in parallel. The objective is to minimize the stopping time, i.e., the time taking for all nodes to receive a copy of the whole messages. We consider an intrinsically one-sided protocol based on random linear network coding (RLNC), where all packets forwarded are in the form of random linear combinations of packets received so far. Its supreme performance is demonstrated theoretically for two cases, low mobility and high mobility, according to the node velocity. In particular, we show that, under general settings, our derived upper bounds of the stopping time match the established lower bound in both cases, although the effects of mobility in the two cases are significantly different. Thus, we conclude that RLNC achieves order optimality for fast information dissemination in MANETs.
    No preview · Article · Jul 2014 · IEEE Transactions on Parallel and Distributed Systems
  • Xiang Lu · Lei Xie · Yafeng Yin · Wei Wang · Baoliu Ye · Sanglu Lu
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    ABSTRACT: With the rapid proliferation of RFID-based applications, RFID tags have been deployed into pervasive spaces in increasingly large numbers, e.g., the shelves of super markets are filled with tag-labeled items. Conventional localization schemes usually leverage precise anchor nodes to help compute the position of objects. However, it is usually difficult to find or deploy enough anchor nodes for accurate localization. In this paper, we propose solutions to locate the mobile users based on imprecise anchors in RFID systems. A large number of tags with approximate locations are used as anchor nodes to compute the user's locations. We thus present a time-efficient localization scheme to continuously tracking the mobile users. Experimental results indicate that our solutions can accurately locate the mobile users in a real-time approach. The improved method's accuracy is more than 30% better than the base solution.
    No preview · Conference Paper · Jun 2014
  • Lei Xie · Sanglu Lu · Yingchun Cao · Daoxu Chen
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    ABSTRACT: Data storage has become an important issue for energy efficient data management in sensor networks. In this paper, we investigate the optimized storage placement problem in large scale sensor networks, aiming to achieve minimized energy cost. In order to efficiently deal with large scale deployment areas with irregular shape, we propose to utilize the hop as the computation unit instead of the node, such that computation complexity can be greatly reduced. We propose methodologies to solve the optimization problem both in situations for limited and unlimited numbers of storage units. The ultimate goal of this paper is to give fundamental guidance for optimized storage placement in large scale sensor networks. Simulation results show that our methodologies can greatly reduce the overall energy consumption compared to other strategies.
    No preview · Article · Jun 2014 · Frontiers of Computer Science (print)
  • Sheng Zhang · Zhuzhong Qian · Jie Wu · Sanglu Lu
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    ABSTRACT: Today's public cloud providers typically deploy their small sized data centers in multiple geographically different locations, so as to improve data center power usage effectiveness and locate resources closer to users. A major challenge is resource allocation. Many results have been reported regarding this issue from the perspectives of virtual machine consolidation, network-aware virtual machine placement, traffic engineering, dynamic capacity provisioning, and so on. However, there has not been any focus on stable resource allocations, where no resource request or data center has any migration incentives. To the best of our knowledge, this paper is the first attempt at gaining a better understanding of the structure of the Stable rEsource Allocation (SEA) problem. We introduce a formal problem statement and develop two algorithms for the 1-dimensional (1-D) and 2-D cases, respectively. Simulation results show that the proposed algorithms have good scalability and convergence.
    No preview · Conference Paper · Jun 2014

Publication Stats

606 Citations
80.50 Total Impact Points

Institutions

  • 2004-2015
    • Nanjing University
      • • State Key Laboratory for Novel Software Technology
      • • Department of Computer Science & Technology
      Nan-ching, Jiangsu Sheng, China
  • 2012
    • Nanjing Institute of Technology
      Nan-ching-hsü, Jiangxi Sheng, China
  • 2011
    • Temple University
      • Department of Computer and Information Science
      Philadelphia, PA, United States
  • 2009
    • University of Electronic Science and Technology of China
      • School of Computer Science and Engineering
      Hua-yang, Sichuan, China
  • 2005-2009
    • The University of Aizu
      • School of Computer Science and Engineering
      Fukushima-shi, Fukushima-ken, Japan
  • 2004-2008
    • The University of Hong Kong
      • Department of Computer Science
      Hong Kong, Hong Kong