10909471
On approximation algorithms of k-connected m-dominating sets in disk graphs
Connected Dominating Set (CDS) has been proposed as the virtual backbone to alleviate the broadcasting storm in wireless ad hoc networks. Most recent research has extensively focused on the construction of 1-Connected 1-Dominating Set (1-CDS) in homogeneous networks. However, the nodes in the CDS need to carry other node's traffic and nodes in wireless networks are subject to failure. Therefore, it is desirable to construct a fault tolerant CDS. In this paper, we study a general fault tolerant CDS problem, called k-Connected m-Dominating Set (k-m-CDS), in heterogeneous networks. We first present two approximation algorithms for 1-m-CDS and k-k-CDS problems. Using disk graphs to model heterogeneous networks, we show that our algorithms have a constant approximation ratio. Based on these two algorithms, we further develop a general algorithm for k-m-CDS. We also provide an interesting analysis for a special case of k-m-CDS, where k=m+1.
42027884
New Approximation for Minimum-Weight Routing Backbone in Wireless Sensor Network
Our problem formulation is as follows. Given a weighted disk graph Gwhere the weight of edge represents the transmission energy consumption, we wish to determine a dominating tree Tof Gsuch that the total weight of edges in Tis minimized. To the best of our knowledge, this problem have not been addressed in the literature. Solving the dominating tree problem can yield a routing backbone for broadcast protocols since: (1) each node does not have to construct their own broadcast tree, (2) utilize the virtual backbone to reduce the message overhead, and (3) the weight of backbone is minimized. 
 
Our contributions to this problem is multi-fold: First, the paper is the first to study this problem, prove the hardness of this problem and propose an approximation framework. Second, we present a heuristic to approximate the solution with low time complexity. Third, a distributed algorithm is provided for practical implementation. Finally, we verify the effectiveness of our proposal through simulation.
14935404
Levels of Authentication Assurance: an Investigation
The ES-LoA project, funded by the UK Joint Information Systems Committee (JISC) under its e- Infrastructure Security Programme, investigates current and future needs among UK research and education community for a more fine-grained authorisation scheme that would allow service providers to take into account of the levels of confidence in identifying a remote entity requesting for service access. Such a fine-grained authorisation scheme is attractive to service providers offering resources with varying levels of sensitivity and/or wishing to tailor their security protections based upon risk levels. Service providers may wish to restrict access to more sensitive resources only to those who have gone through a more stringent authentication process, or given the same remote entity, require the use of a stronger authentication token should the access request come from a more risky environment. In this way, the quality of an authentication instance, expressed as an authentication Level of Assurance (LoA), becomes one of the parameters used in access control decision making. This paper investigates the current worldwide efforts in defining LoA and identifies gaps in existing definitions when they are applied to a federated environment.
13044783
A New Time-domain Detection Approach with Blind Separation Based on Neural Network
In this paper a new technique is proposed for time-domain detection in energy detection. The proposed scheme is based on a independent-component analysis (ICA): blind separation of unknown source signals. This method not only improves the nicety of time-domain detection for narrow band signal and the sinusoidal signal but also reduces the power of the whole detection system.
1660866
A General Fuzzified CMAC Controller with Eligibility
This paper presents an online neural network controller. Cerebellar Model Articulation Controller (CMAC) is suitable to online control due to its fast learning speed. By integrating the CMAC address scheme with fuzzy logic concept, a general fuzzified CMAC (GFAC) is proposed. Then by incorporating the concept of eligibility into the GFAC, a GFAC controller with eligibility is presented, named FACE. A learning algorithm for the FACE is derived to tune the model parameters. To achieve online control, an efficient implementation of the proposed FACE method is presented. As an example, the proposed FACE is applied to a ship steering control system. The simulation results show that the ship course can be properly controlled under the disturbances of wave, wind and current.
1884872
A mobility monitoring based advance reservation protocol
Future wireless cellular networks will be Internet Protocol (IP) based. Users of wireless devices in these networks will expect to run real-time applications that require guarantees of Quality of Service (QoS). Such a user will expect the same seamless QoS that he would receive if he were running real-time applications on a wired network. Achieving seamless QoS in a mobile environment implies that a reservation should be re-established at the new Base Station (BS) before hand-over occurs. However, making these advance reservations is wasteful of valuable bandwidth in the wireless network. This paper proposes a protocol, called the Mobility Monitoring Based Advance Reservation Protocol (M²BARP), which aims to reduce the bandwidth overhead of making advance reservations. The protocol makes use of information about a Mobile Node's (MN) mobility to make a single advance reservation when the MN is about to hand-over. Unlike previous work, M²BARP takes advantage of overlapping cells to help to provide a more seamless QoS by reducing the number of calls dropped at hand-over
43179362
On the crosscorrelation of generalized Barker sequences
Some communication systems require sets of signals in which each signal can be easily distinguished from all time-shifted versions of itself, and from every other signal in the set. A generalized Barker sequence can be easily distinguished from the time-shifted versions of itself. It is shown that distinguishing between a generalized Barker sequence and any other generalized Barker sequence of the same length is inherently harder than distinguishing the sequence from time-shifted versions of itself. >
26378993
Dynamic output feedback H/sup /spl infin// controller design of fuzzy dynamic systems using LMI techniques
Presents output feedback H/sup /spl infin// controller design methods for fuzzy dynamic systems. Three kinds of controller design methods are proposed based on a smooth Lyapunov function or a piecewise smooth Lyapunov function. The control laws are obtained by using LMI techniques and the global stability with disturbance attenuation of the closed-loop fuzzy control system is established.
11989987
A comprehensive simulation study of SWAN QoS model in MANETs with proactive and reactive routing
In this paper, one of the QoS models for MANETs - SWAN is studied under varying conditions to provide both quantitative and qualitative assessments of the applicability of the model in different scenarios. Results and analysis from NS-2 based simulation indicate that (i) real-time (RT) applications in SWAN-enabled mobile ad hoc networks experience low and stable delays under various traffic and mobility environment at the expense of best-effort (BE) traffic, (ii) SWAN model works compatibly with proactive as well as reactive routing protocols. A careful choice of parameters is important to balance the throughput of the BE traffic and RT traffic and QoS provisions in MANETs.
3386880
Statistical Learning Techniques for Costing XML Queries
Developing cost models for query optimization is significantly harder for XML queries than for traditional relational queries. The reason is that XML query operators are much more complex than relational operators such as table scans and joins. In this paper, we propose a new approach, called COMET, to modeling the cost of XML operators; to our knowledge, COMET is the first method ever proposed for addressing the XML query costing problem. As in relational cost estimation, COMET exploits a set of system catalog statistics that summarizes the XML data; the set of "simple path" statistics that we propose is new, and is well suited to the XML setting. Unlike the traditional approach, COMET uses a new statistical learning technique called "transform regression" instead of detailed analytical models to predict the overall cost. Besides rendering the cost estimation problem tractable for XML queries, COMET has the further advantage of enabling the query optimizer to be self-tuning, automatically adapting to changes over time in the query workload and in the system environment. We demonstrate COMET's feasibility by developing a cost model for the recently proposed XNAV navigational operator. Empirical studies with synthetic, benchmark, and real-world data sets show that COMET can quickly obtain accurate cost estimates for a variety of XML queries and data sets.
18987585
Efficient elliptic curve scalar multiplication algorithms resistant to power analysis
This paper presents four algorithms for securing elliptic curve scalar multiplication against power analysis. The highest-weight binary form (HBF) of scalars and randomization are applied to resist power analysis. By using a special method to recode the scalars, the proposed algorithms do not suffer from simple power analysis (SPA). With the randomization of the secret scalar or base point, three of the four algorithms are secure against differential power analysis (DPA), refined power analysis (RPA) and zero-value point attacks (ZPA). The countermeasures are also immune to the doubling attack. Fast Shamir's method is used in order to improve the efficiency of parallel scalar multiplication. Compared with previous countermeasures, the new countermeasures achieve higher security and do not impact overall performance.