Sanglu Lu

Nanjing University, Nan-ching, Jiangsu Sheng, China

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Publications (111)24.13 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The advances of Radio-Frequency Identification (RFID) technology have significantly enhanced the capability of capturing data from pervasive space. It becomes a great challenge in the information era to effectively understand human behavior, mobility and activity through the perceived RFID data. Focusing on RFID data management, this article provides an overview of current challenges, emerging opportunities and recent progresses in RFID. In particular, this article has described and analyzed the research work on three aspects: algorithm, protocol and performance evaluation. We investigate the research progress in RFID with anti-collision algorithms, authentication and privacy protection protocols, localization and activity sensing, as well as performance tuning in realistic settings. We emphasize the basic principles of RFID data management to understand the state-of-the-art and to address directions of future research in RFID.
    IEEE Communications Surveys &amp Tutorials 01/2014; 16(3):1294-1311. · 4.82 Impact Factor
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    ABSTRACT: Network virtualization has emerged as a promising approach to overcome the ossification of the Internet. A major challenge in network virtualization is the so-called virtual network embedding problem, which deals with the efficient embedding of virtual networks with resource constraints into a shared substrate network. A number of heuristics have been proposed to cope with the NP-hardness of this problem; however, all of the existing proposals reserve fixed resources throughout the entire lifetime of a virtual network. In this paper, we re-examine this problem with the position that time-varying resource requirements of virtual networks should be taken into consideration, and we present an opportunistic resource sharing-based mapping framework, ORS, where substrate resources are opportunistically shared among multiple virtual networks. We formulate the time slot assignment as an optimization problem; then, we prove the decision version of the problem to be NP-hard in the strong sense. Observing the resemblance between our problem and the bin packing problem, we adopt the core idea of first-fit and propose two practical solutions: first-fit by collision probability (CFF) and first-fit by expectation of indicators' sum (EFF). Simulation results show that ORS provides a more efficient utilization of substrate resources than two state-of-the-art fixed-resource embedding schemes.
    IEEE Transactions on Parallel and Distributed Systems 01/2014; 25(3):816-827. · 1.80 Impact Factor
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    ABSTRACT: It is a tedious task to search and locate a specific food from a massive number of foods arbitrarily placed in a fridge. In this paper, we develop iFridge, an intelligent system which allows the user to effectively manage and accurately locate the foods stored inside the fridge. By leveraging the RFID technology, iFridge is able to automatically collect the food information, perceive the user's activities and locate the specified foods. We develop a smart application "cooking recipe recommendation" by sensing the user's daily eating habits. Moreover, by specifying those foods with roughly known locations as anchor nodes, we are able to locate the specified food by using cluster analysis.
    Proceedings of the 2013 ACM conference on Pervasive and ubiquitous computing adjunct publication; 09/2013
  • Bin Tang, Baoliu Ye, Sanglu Lu, Song Guo
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    ABSTRACT: In recent years, OFDMA relay networks have become a key component in the 4G standards (e.g., IEEE 802.16j, 3GPP LTE-Advanced) for broadband wireless access. When numerous bidirectional flows pass through the relay stations in an OFDMA relay network that supports various interactive applications, plenty of network coding opportunities arise and can be leveraged to enhance the throughput. In this paper, we study the proportional-fair scheduling problem in the presence of network coding in OFDMA relay networks. Considering the tradeoff between performance and overhead, we propose two models, global approach (GA) and local approach (LA), under which the corresponding problems are shown both NP-hard. For the GA model, we show that it cannot be approximated within some constant factor. Hence, we propose a heuristic algorithm with low time complexity. For the LA model, we propose a theoretical polynomial time approximation scheme (PTAS), and also present a practical greedy algorithm with approximation factor of 1/2. Simulation results show that our algorithms can achieve significant throughput improvement over a state-of-the-art noncoding scheme.
    IEEE Transactions on Parallel and Distributed Systems 09/2013; 24(9):1727-1740. · 1.80 Impact Factor
  • Sheng Zhang, Jie Wu, Sanglu Lu
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    ABSTRACT: This paper poses the following problem: given a task that originates at some node in a Delay Tolerant Network (DTN), how are we to disseminate the workload during pairwise contacts to minimize the makespan? We first investigate the scenario in which each node has access to an oracle that knows global and future knowledge of node mobility, and we propose a centralized polynomial-time optimal algorithm. We then develop a distributed dissemination protocol, D2, which maintains r-hop neighborhood information at individual nodes. D2 makes dissemination decisions based on the estimations of the potential computational capacities and the future workloads of DTN nodes. Using trace-driven simulations, we show that, D2 with only 1-hop information is already near-optimal in a wide variety of environments, and the performance gap becomes smaller as the amount of information maintained at individual nodes increases.
    Proceedings of the fourteenth ACM international symposium on Mobile ad hoc networking and computing; 07/2013
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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.
    Proceedings of the fourteenth ACM international symposium on Mobile ad hoc networking and computing; 07/2013
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    ABSTRACT: Chunked codes are a variation of random linear network codes with low computational complexities in terms of encoding and decoding, where the input packets are grouped into small (non-overlapped or overlapped) chunks, and random linear coding are performed within each chunk. In this paper, we focus on chunked codes with a constant chunk size. We first highlight the importance of precoding for chunked codes to achieve non-vanishing rates, and then analyze the achievable rates of the non-overlapped chunked (NOC) codes with precoding. We further introduce a new class of chunked codes, called Expander Chunked (EC) codes, which use expander graphs to form (overlapped) chunks, and derive their achievable rates using a tree-based analysis as well as some expander arguments. Numerical results reveal that EC codes perform near-optimally, and achieve significantly higher rates than NOC codes. Also, simulation results show that for finite number of input packets, EC codes incur much lower transmission overhead to recover the whole input packets than other state-of-the-art chunked codes.
    07/2013;
  • 8th IEEE symposium on Computers and Communications (ISCC 2013); 07/2013
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    ABSTRACT: Many emerging online stream processing services require the consideration of quality of service (QoS), which is highly dependent on the placement of services at various hosts. This paper investigates the QoS-aware placement problems of stream processing services under different contexts. On condition that the client demands are stable, the QoS-aware placement problem aiming to minimize the cost when servers are CPU-uncapacitated, is equivalent to the set cover problem, and can be solved by a greedy algorithm with approximation factor O(log n), where nis the number of clients. However, when CPU capacity constraints on servers are taken into account, the QoS-aware placement problem cannot be approximated unless P=NP. Therefore, we propose two heuristic algorithms: (1) ISCA (Iterated Set Cover-based Algorithm) and (2) KBA (Knapsack-Based Algorithm). We also consider the placement problem of client demands increasing over time. Two objectives, called extension factor and system lifetime, are proposed for demand increment-blind and increment-aware models respectively. Both of them can be solved by extending ISCA and KBA. The experimental results show that ISCA and KBA have distinct effects on different demand sizes. ISCA is more efficient when client demands are relatively small, while KBA performs better for larger demands. KeywordsStream processing service–Service placement–QoS-aware
    The Journal of Supercomputing 06/2013; · 0.92 Impact Factor
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    ABSTRACT: The past few years have witnessed an explosive popularity of mobile services, especially in the form of smart phone applications. To cope with the limited batteries and computational capacities of mobile devices, prior studies suggest to deploy service instances in clouds for accomplishing most of the computation-intensive tasks. Service composition, which compensates for the simplicity of single service, is an effective way to utilize the plentiful services on the clouds all over the world. In this paper, we focus on the problem of service instance selection with service instance replica limitation constraint. The objective is to select the optimal set of service instances, which composes the integrated service and brings out the optimal QoS (quality of service), in terms of service response time. To characterize the problem, we establish a new QoS model, which considers the comprehensive quality over all users, not just for any single user or service instance. We prove that the problem is NP-hard, since many functionally equivalent service instances spread all over the distributed clouds. To address the problem, we classify the problem into three cases, including two special cases and the general case. We present two effective heuristic algorithms to determine the service instances selection for the two special cases, which are still NP-hard. The two special cases provide empirical bounds for the general case. We propose an algorithm that simulates a vote procedure for the users in the general case. The selected service instances, which come from the vote procedure, can satisfy a majority of users. We conduct extensive simulations for all of the algorithms. The simulation results show that our algorithms work efficiently on service response time reduction.
    International Journal of Information Management. 01/2013;
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    ABSTRACT: Energy efficiency is a critical issue for cloud computing as more and more Internet services are deployed in data centers. It is observed that the energy consumption increases significantly as the CPU frequency gets higher. To reduce the total energy, Dynamic Voltage and Frequency Scaling (DVFS) technique is proposed to make the CPUs working at proper frequencies. However, lower frequency will reduce the computing capacity of the servers, which leads to using more servers. It is a challenging problem to make a tradeoff between the number of servers and the frequency of each server for a given workload. In this paper, we prove that the problem of dynamic resource allocation based on DVFS with the target of minimizing energy consumption is NP-Hard. And we propose two algorithms based on different basic ideas to solve this problem. We also compare our algorithms to the well-known First Fit Decreasing (FFD) algorithm, and the simulation results show that we can get 12%-14% power saving on average although we use 1.2x-1.3x number of servers compared to FFD.
    Innovative Mobile and Internet Services in Ubiquitous Computing (IMIS), 2013 Seventh International Conference on; 01/2013
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    ABSTRACT: Although the capacity of wireless ad hoc networks has been extensively studied under different mobility models and network settings, few work has been done on the effect of heterogeneous mobile nodes and correlated mobility. In this paper, we consider the heterogeneous wireless networks consisting of two types of nodes, called user nodes and master nodes. Specifically, user nodes are combined into groups and each group is equipped with a more powerful master node serving as relay for packet transmissions among groups. By proposing a simple, asymptotically optimal scheduling and routing scheme, we present the maximum per-node throughput and the end-to-end delay in order sense, respectively. We also explore the trade-offs between capacity and delay by adjusting network settings.
    Wireless Communications and Networking Conference (WCNC), 2013 IEEE; 01/2013
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    ABSTRACT: Due to different requirements in applications, sensors with different capacities are deployed. How to design efficient, reliable and scalable routing protocols in such wireless heterogeneous sensor networks (WHSNs) with intermittent asymmetric links is a challenging task. In this paper, we propose ProHet: a distributed probabilistic routing protocol for WHSNs that utilizes asymmetric links to reach assured delivery rate with low overhead. The ProHet protocol first produces a bidirectional routing abstraction by finding a reverse path for every asymmetric link. Then, it uses a probabilistic strategy to choose forwarding nodes based on historical statistics using local information. Analysis shows that ProHet can achieve assured delivery rate ρ if ρ is set within its upper-bound. Extensive simulations are conducted to verify its efficiency.
    IEEE Transactions on Wireless Communications 01/2013; 12(4):1524-1531. · 2.42 Impact Factor
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    ABSTRACT: Communication networks are vulnerable to the natural disasters or malicious attacks, which may cause a large area of corruptions and long term disconnection of network services. Such significant outage has become a serious problem today with regard to the stringent reliability requirement of the mission critical applications. In this paper, we focus on fast and effective failure recovery in face of region failures. Rather than rely on the time consuming failure localization, we introduce and evaluate a direct restoration mechanism upon detecting the path failure, which use the geographically distributed intermediate nodes, named “landmarks”, to reestablish the connection through a (near-)shortest detour path. The experimental analysis on randomly generated and realistic network topologies have shown that this approach can achieve high reliability and low stretch in case of region failures, and thus significantly reduce the impact of region failures on network based mission critical services.
    Design of Reliable Communication Networks (DRCN), 2013 9th International Conference on the; 01/2013
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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 a large set of 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 propose two efficient protocols based on the collision detection and the logical features of rules, respectively. Simulation results indicate that our protocols achieve much better performance than other solutions in terms of time efficiency.
    Computer Communications and Networks (ICCCN), 2013 22nd International Conference on; 01/2013
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    ABSTRACT: It is a tedious task to search and locate a specific book from massive number of books arbitrarily placed in a bookshelf. In this paper, we demonstrate iBookshelf, a system which allows users to quickly search and accurately locate books in the bookshelf, by leveraging a passive RFID system. By deploying a number of reference tags on the bookshelf, we are able to perform localization based on the similarities in received signal strength, and effectively offset the impact from the ambient noises and interferences. We deploy and evaluate our system in a real 3m x 2.5m bookshelf, and show that users are able to locate the book from our Android-based application with 85% accuracy.
    Proceedings of the 10th ACM Conference on Embedded Network Sensor Systems; 11/2012
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    ABSTRACT: Data caching is widely used to facilitate information access in wireless mobile networks. Caching frequently used content on mobile clients brings benefits by reducing bandwidth usage, saving energy, and leveraging server workload. Maintaining cache consistency is an important issue in mobile caching and has received much attention by researchers. However, most existing studies on cache consistency strategies are limited to cellular wireless networks in which the mobile terminals can communicate with the base stations directly. In multi-hop wireless network environment, mobile terminals communicate with data server through multiple unreliable links with a high probability of disconnection from the network, which makes it more challenging for the maintenance of cache data consistency. In this paper, we investigate three cache consistency strategies for multi-hop wireless networks: the pull-based strategy POD (pull on demand), the push-based strategy MAT (modified amnesic terminals) and the store and forward strategy PIR (pull-based invalidation report). Extensive theoretical analysis is provided to compare the cache hit ratio, query delay and communication overhead of these methods, and the impact of system parameters on performance is studied as well. Simulation experiments are used to examine the performance of these three schemes, and it is shown that PIR provides the best overall performance.
    The Journal of Supercomputing 11/2012; 62(2). · 0.92 Impact Factor
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    ABSTRACT: Vehicular Ad Hoc Networks (VANETs) enable car-to-car communication without the support of network infrastructure, which introduce diverse application possibilities and have drawn much attention from academy and industry in the past years. Unlike other ad hoc networks, nodes in VANETs are restricted to move in streets and have limited communication ranges. Intuitively, vehicle-to-vehicle communication somehow has similarity to human-to-human interaction, which lead to an interesting question of exploring the social properties of VANET nodes. To address the question, we consider encounters of vehicles as their social relationships and model VANETs as social graphs. Based on the social graph model, we use two traces of mobile vehicles from San Francisco and Shanghai to explore their social properties. Our analysis show that several universal laws of social network are hold for VANETs. The social graphs forming by vehicles are scale-free networks with power-law like distribution of node degrees. Small world phenomenon is also observed in our experiments: the nodes in VANETs have high cluster coefficient and there exist short paths between node pairs less than 3 hops on average. The implication of our analytical results is of benefit to develop large scale software system for mobile applications such as VANETs, as well as helps to facilitate inter-device wireless communications in pervasive environment.
    Proceedings of the Fourth Asia-Pacific Symposium on Internetware; 10/2012
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    ABSTRACT: Cloud computing is a newly emerging reliable and scalable paradigm in which customers pay for cloud resources they use on demand. However, current auto-scaling mechanisms in cloud lack the critical self-adaption policy which helps application providers decide on when and how to reallocate resources. Furthermore, virtualization techniques can not ensure an absolute isolation between multiple virtual machines sharing the same physical resource, which leads to some customers paying unfairly for heavy-loaded resource under a widely-adopted fixed pricing scheme. In this paper, we present a global performance-to-price model based on game theory, in which each application is considered as a selfish player attempting to guarantee QoS requirements and simultaneously minimize the resource cost. Then we apply the idea of Nash equilibrium to obtain the appropriate allocation, and an approximated solution is proposed to obtain the Nash equilibrium, ensuring that each player is charged fairly for their desired performance. First, each player maximizes its utility independently without considering the placement of virtual machines. Then based on the initial allocation, each player reaches its optimal placement solely without considering others' interference. Finally we propose an evolutionary algorithm which step by step updates the global resource allocation based on the initial optimal allocation and placement.
    Proceedings of the Fourth Asia-Pacific Symposium on Internetware; 10/2012
  • Sanglu Lu, Jie Wu, Sheng Zhang
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    ABSTRACT: The limited battery capacity of sensor nodes has become the biggest impediment to wireless sensor network (WSN) applications. Two recent breakthroughs in the areas of wireless energy transfer and rechargeable lithium batteries promise the use of mobile vehicles, with high volume batteries, as mobile chargers that transfer energy to sensor nodes wirelessly. In this paper, for the first time, we envision a novel charging paradigm: collaborative mobile charging, where mobile chargers are allowed to charge each other. We investigate the problem of scheduling multiple mobile chargers, which collaboratively recharge sensors, to maximize the ratio of the amount of payload energy to overhead energy, such that every sensor will not run out of energy. We first consider the uniform case where all sensors consume energy at the same rate, and propose a scheduling algorithm, PushWait, which is proven to be optimal in this case and can cover a one-dimensional WSN of infinite length. Then, in the non-uniform case, which is conjectured to be NP-hard, we first present two observations from space and time aspects to remove some impossible scheduling choices, and we propose our heuristic algorithm, ClusterCharging(β), which clusters sensors into groups and divides a scheduling cycle into charging rounds. Its approximation ratio is also presented. Extensive evaluations confirm the efficiency of our algorithms.
    Proceedings of the 2012 IEEE 9th International Conference on Mobile Ad-Hoc and Sensor Systems (MASS); 10/2012

Publication Stats

188 Citations
24.13 Total Impact Points

Institutions

  • 2004–2014
    • Nanjing University
      • • State Key Laboratory for Novel Software Technology
      • • Department of Computer Science & Technology
      Nan-ching, Jiangsu Sheng, China
  • 2010–2011
    • Temple University
      • Department of Computer and Information Science
      Philadelphia, PA, United States
    • College of William and Mary
      • Department of Computer Science
      Williamsburg, VA, United States
  • 2009
    • University of Electronic Science and Technology of China
      • School of Computer Science and Engineering
      Chengdu, Sichuan Sheng, China
  • 2007–2009
    • The University of Aizu
      • School of Computer Science and Engineering
      Fukushima-shi, Fukushima-ken, Japan
    • Nanjing Audit University
      Nan-ching, Jiangsu Sheng, China
  • 2008
    • The University of Hong Kong
      • Department of Computer Science
      Hong Kong, Hong Kong
  • 2000
    • Ecole Nationale Supérieure d'Informatique
      Alger, Alger, Algeria
    • University of Queensland
      Brisbane, Queensland, Australia