Publications (11)1.65 Total impact
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ABSTRACT: In this paper we consider how to collect data from sensors deployed in the Euclidean plane in a timeefficient way. We assume that all sensors could adjust their transmission ranges and aggregate data received from other sensors. We adopt a collisionfree transmission model using proper schedules for data transmission. We study the problem of finding the schedule under which data from all sensors could be transmitted to the data sink in the minimal time. We propose an approximation algorithm for this NPhard problem whose performance ratio is bounded by a constant. This significantly improves the existing approximation algorithm that does not have a constant performance ratio.Wireless Networks 01/2010; 16:13451353. · 0.74 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: Minimum mconnected kdominating set problem is as follows: Given a graph G=(V,E) and two natural numbers m and k, find a subset S⊆V of minimal size such that every vertex in V∖S is adjacent to at least k vertices in S and the induced graph of S is mconnected. In this paper we study this problem with unit disc graphs and small m, which is motivated by the design of faulttolerant virtual backbone for wireless sensor networks. We propose two approximation algorithms with constant performance ratios for m≤2. We also discuss how to design approximation algorithms for the problem with arbitrarily large m.Journal of Combinatorial Optimization 07/2008; 16(2):99106. · 0.59 Impact Factor 
Article: On minimum
J. Comb. Optim. 01/2008; 16:99106. 
Conference Paper: MinimumLatency Broadcast Scheduling in Wireless Ad Hoc Networks
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ABSTRACT: A wide range of applications for wireless ad hoc networks are timecritical and impose stringent requirement on the communication latency. This paper studies the problem MinimumLatency Broadcast Scheduling (MLBS) in wireless ad hoc networks represented by unitdisk graphs. This problem is NPhard. A trivial lower bound on the minimum broadcast latency is the radius R of the network with respect to the source of the broadcast, which is the maximum distance of all the nodes from the source of the broadcast. The previously bestknown approximation algorithm for MLBS produces a broadcast schedule with latency at most 648 R. In this paper, we present three progressively improved approximation algorithms for MLBS. They produce broadcast schedules with latency at most 24 R 23, 16 R 15, and R + O (log R) respectively.INFOCOM 2007. 26th IEEE International Conference on Computer Communications. IEEE; 06/2007 
Conference Paper: The Roman Domination Problem in Unit Disk Graphs.
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ABSTRACT: Unit disk graphs are the intersection graphs of equal sized disks in the plane, they are widely used as a mathematical model for wireless adhoc networks and some problems in computational geometry. In this paper we first show that the Roman domination problem in unit disk graphs is NPhard, and then present a simple linear time approximation algorithm and a polynomialtime approximation scheme for this problem, respectively.Computational Science  ICCS 2007, 7th International Conference, Beijing, China, May 27  30, 2007, Proceedings, Part III; 01/2007  [Show abstract] [Hide abstract]
ABSTRACT: Given a wired network of processors, and a source node that needs to broadcast a message to all other processors in the network, the minimum broadcast time problem is to find a scheme that accomplishes the broadcast in a minimum number of time rounds under the constraint that at each time round, no processor can forward the received message to more than one of its neighbors in the network. This NPhard problem has been extensively studied in literatures. In this paper we focus on a variant of the minimum broadcast time problem: the minimum multicast time problem in wireless sensor networks under collisionfree data transmission model. The goal of the problem is to multicast a message from the source node to a set of destination nodes in a minimum number of time rounds. This problem remains NPhard even in the Euclidean plane and the current best approximation algorithm has performance ratio of 41. In this paper we propose a new algorithm that has performance ratio of 15.IEEE Wireless Communications and Networking Conference, WCNC 2007, Hong Kong, China, 1115 March, 2007; 01/2007  [Show abstract] [Hide abstract]
ABSTRACT: In wireless sensor networks, a virtual backbone has been proposed as the routing infrastructure to alleviate the broadcasting storm problem and perform some other tasks such as area monitoring. Previous work in this area has mainly focused on how to set up a small virtual backbone for high efficiency, which is modelled as the minimum Connected Dominating Set (CDS) problem. In this paper we consider how to establish a small virtual backbone to balance efficiency and fault tolerance. This problem can be formalized as the minimum mconnected ktuple dominating set problem, which is a general version of minimum CDS problem with m=1 and k=1. We propose three centralized algorithms with small approximation ratios for small m and improve the current best results for small k.Theor. Comput. Sci. 01/2007; 381:241247. 
Conference Paper: Algorithms for Minimum
Combinatorial Optimization and Applications, First International Conference, COCOA 2007, Xi'an, China, August 1416, 2007, Proceedings; 01/2007  [Show abstract] [Hide abstract]
ABSTRACT: We show in this paper that the upper minus domination number Γ(G) of a clawfree cubic graph G is at most .Discrete Mathematics. 01/2006;  [Show abstract] [Hide abstract]
ABSTRACT: In wireless sensor networks, virtual backbone has been proposed as the routing infrastructure to alleviate the broadcasting storm problem and perform some other tasks such as area monitoring. Previous work in this area has mainly focused on how to set up a small virtual backbone for high efficiency, which is modelled as the minimum Connected Dominating Set (CDS) problem. In this paper we consider how to establish a small virtual backbone to balance efficiency and fault tolerance. This problem can be formalized as the minimum mconnected kdominating set problem, which is a general version of minimum CDS problem with m = 1 and k = 1. In this paper we will propose some approximation algorithms for this problem that beat the current best performance ratios.01/1970: pages 182190; 
Article: Approximation algorithms for minimum broadcast schedule problem in wireless sensor networks
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ABSTRACT: A wireless sensor network usually consists of a large number of sensor nodes deployed in a field. One of the major communication operations is to broadcast a message from one node to the rest of the others. In this paper, we adopt the conflictfree communication model and study how to compute a transmission schedule that determines when and where a node should forward the message so that all nodes could receive the message in minimum time. We give two approximation algorithms for this NPhard problem that have better theoretically guaranteed performances than the existing algorithms. The proposed approach could be applied to some other similar problems. Keywordsbroadcast scheduleapproximation algorithmwireless sensor networkunit disk graph MSC90B18Frontiers of Mathematics in China 5(1):7587. · 0.32 Impact Factor
Publication Stats
76  Citations  
1.65  Total Impact Points  
Top Journals
Institutions

2006–2010

Zhengzhou University
 Department of Mathematics
Zhengzhou, Henan Sheng, China


2006–2008

Chinese Academy of Sciences
 Institute of Applied Mathematics
Peping, Beijing, China


2007

Northeast Institute of Geography and Agroecology
 Institute of Applied Mathematics
Peping, Beijing, China 
The University of Hong Kong
 Department of Computer Science
Hong Kong, Hong Kong


1970

City University of Hong Kong
 Department of Computer Science
Chiulung, Kowloon City, Hong Kong
