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Dirty paper coding are relevant for wireless networks, multiuser channels, and digital watermarking. We show that the problem of dirty paper is essentially equivalent to some classes of constrained memories, and we explore the binary so-called nested codes, which are used for efficient coding and error-correction on such channels and memories. Keywords: dirty paper, constrained memory, nested codes, covering codes. [ABSTRACT FROM AUTHOR]

This paper is concerned with a multi-resolution tool for analysis of a time series aiming to detect abnormalities in various frequency regions. The task is treated as a kernel based novelty detection applied to a multi-level time series representation obtained from the discrete wavelet transform. Having a priori knowledge that the abnormalities manifest themselves in several frequency regions, a committee of detectors utilizing data dependent aggregation weights is build by combining outputs of detectors operating in those regions. [ABSTRACT FROM AUTHOR]

One of the simplest protocols for clock synchronization in wireless ad hoc and sensor networks is the converge-to-max protocol, which has the simple logic of adjusting each node's clock to be at least as large as any neighbor's. This paper examines the converge-to-max protocol, showing it to be stabilizing even when node clocks have skew, bounded domains, and dynamic communication links. [ABSTRACT FROM AUTHOR]

In this paper we extend the Least Squares Monte Carlo approach proposed by Longstaff and Schwartz for the valuation of American-style contingent-claims to the case of life insurance contracts. These contracts, in fact, often embed an American-style option, called surrender option, that entitles its owner to terminate early the contract and receive a cash amount, called surrender value. The additional complication arising in life insurance policies with respect to purely financial American contracts is that there is not a fixed date within which the option can be exercised, since its "maturity" is driven by mortality factors. This complication has been handled by very few papers, often at the cost of excessively simplified valuation frameworks. The aim of this contribution, that is not a specific valuation model but a methodological approach, is to allow a full exploitation of the flexibility inborn in Monte Carlo and quasi-Monte Carlo methods in order to deal with more realistic valuation frameworks. [ABSTRACT FROM AUTHOR]

Genetic programming has been used by Koza and many others to design electrical, mechanical, and mechatronic systems, including systems with both active and passive components. This work has often required large population sizes (on the order of ten thousand) and millions of design evaluations to allow evolution of both the topology and parameters of interesting systems. For several years, the authors have studied the evolution of multi-domain engineering systems represented as bond graphs, a form that provides a unified representation of mechanical, electrical, hydraulic, pneumatic, thermal, and other systems in a uni-fied representation. Using this approach, called the Genetic Programming/Bond Graph (GPBG) approach, they have tried to evolve systems with perhaps tens of components, but looking at only 100,000 or fewer design candidates. The GPBG system uses much smaller population sizes, but seeks to maintain diverse search by using "sustained" evolutionary search processes such as the Hierarchical Fair Competition principle and its derivatives. It uses stochastic setting of parameter values (resistances, capacitances, etc.) as a means of evolving more robust designs. However, in past work, the GPBG system was able to model and simulate only passive components and simple (voltage or current, in the case of electrical systems) sources, which severely restricted the domain of problems it could address. Thus, this paper reports the first steps in enhancing the system to include active components. To date, only three models of a transistor and one model of an operational amplifier (op amp) are analyzed and implemented as two-port bond graph components. The analysis method and design strategy can be easily extended to other models or other active components or even multi-port components. This chapter describes design of an active analog low-pass filter with fifth-order Bessel characteristics. A passive filter with the same characteristics is also evolved with GPBG. Then the best designs emerging from each of these two procedures are compared. [The runs reported here are intended only to document that the analysis tools are working, and to begin study of the effects of stochasticity, but not to determine the power of the design procedure. The initial runs did not use HFC or structure fitness sharing, which will be included as soon as possible. Suitable problems will be tackled, and results with suitable numbers of replicates to allow drawing of statistically valid conclusions will be reported in this paper, to determine whether interesting circuits can be evolved more efficiently in this framework than using other GP approaches.] [ABSTRACT FROM AUTHOR]

This paper studies a gathering problem for a system of asynchronous autonomous mobile robots that can move freely in a two-dimensional plane. We consider robots equipped with inaccurate (incorrect) compasses which may point a different direction from other robots' compasses. A gathering problem is that the robots are required to eventually gather at a single point which is not given in advance from any initial configuration. In this paper, we propose several inaccurate compass models and give two algorithms which solve the gathering problem on these models. One algorithm is the first result dealing with the compasses whose indicated direction may change in every beginning of execution cycles of robots. It solves the problem when compasses point different at most π/8 from the (absolute) north. The other one solves the problem when the compasses never change its pointed direction and their difference is at most π/3 among robots. [ABSTRACT FROM AUTHOR]

Recently, quite a few papers studied methods for representing network properties by assigning informative labels to the vertices of a network. Consulting the labels given to any two vertices u and v for some function f (e.g. "distance(u,v)") one can compute the function (e.g. the graph distance between u and v). Some very involved lower bounds for the sizes of the labels were proven. In this paper, we demonstrate that such lower bounds are very sensitive to the number of vertices consulted. That is, we show several almost trivial constructions of such labeling schemes that beat the lower bounds by large margins. The catch is that one needs to consult the labels of three vertices instead of two. We term our generalized model labeling schemes with queries. Additional contributions are several extensions. In particular, we show that it is easy to extend our schemes for tree to work also in the dynamic scenario. We also demonstrate that the study of the queries model can help in designing a scheme for the traditional model too. Finally, we demonstrate extensions to the non-distributed environment. In particular, we show that one can preprocess a general weighted graph using almost linear space so that flow queries can be answered in almost constant time. [ABSTRACT FROM AUTHOR]

The M-renaming problem consists in providing the processes with a new name taken from a new name space of size M. A renaming algorithm is adaptive if the size M depends on the number of processes that want to acquire a new name (and not on the total number n of processes). Assuming each process proposes a value, the k-set agreement problem allows each process to decide a proposed value in such a way that at most k different values are decided. In an asynchronous system prone to up to t process crash failures, and where processes can cooperate by accessing atomic read/write registers only, the best that can be done is a renaming space of size M = p + t where p is the number of processes that participate in the renaming. In the same setting, the k-set agreement problem cannot be solved for t ≥ k. This paper focuses on the way a solution to the renaming problem can help solving the k-set agreement problem when k ≤ t. It has several contributions. The first is a t-resilient algorithm (1 ≤ t < n) that solves the k-set agreement problem from any adaptive (n + k − 1)-renaming algorithm, when k = t. The second contribution is a lower bound that shows that there is no wait-free k-set algorithm based on an (n + k − 1)-renaming algorithm that works for any value of n, when k < t. This bound shows that, while a solution to the (n + k − 1)-renaming problem allows solving the k-set agreement problem despite t = k failures, such an additional power is useless when k < t. In that sense, in an asynchronous system made up of atomic registers, (n + k − 1)-renaming allows progressing from k > t to k = t, but does not allow bypassing that frontier. The last contribution of the paper is a wait-free algorithm that constructs an adaptive (n + k − 1)-renaming algorithm, for any value of the pair (t,k), from a failure detector of the class $\Omega^k_*$ (this last algorithm is a simple adaptation of an existing renaming algorithm). [ABSTRACT FROM AUTHOR]

We consider the problem of periodic exploration of all nodes in undirected graphs by using a finite state automaton called later a robot. The robot, using a constant number of states (memory bits), must be able to explore any unknown anonymous graph. The nodes in the graph are neither labelled nor colored. However, while visiting a node v the robot can distinguish between edges incident to it. The edges are ordered and labelled by consecutive integers 1,...,d(v) called port numbers, where d(v) is the degree of v. Periodic graph exploration requires that the automaton has to visit every node infinitely many times in a periodic manner. Note that the problem is unsolvable if the local port numbers are set arbitrarily, see [8]. In this context, we are looking for the minimum function π(n), such that, there exists an efficient deterministic algorithm for setting the local port numbers allowing the robot to explore all graphs of size n along a traversal route with the period π(n). Dobrev et al. proved in [13] that for oblivious robots π(n) ≤ 10n. Recently Ilcinkas proposed another port labelling algorithm for robots equipped with two extra memory bits, see [20], where the exploration period π(n) ≤ 4n − 2. In the same paper, it is conjectured that the bound 4n − O(1) is tight even if the use of larger memory is allowed. In this paper, we disprove this conjecture presenting an efficient deterministic algorithm arranging the port numbers, such that, the robot equipped with a constant number of bits is able to complete the traversal period in π(n) ≤ 3.75n − 2 steps hence decreasing the existing upper bound. This reduces the gap with the lower bound of π(n) ≥ 2n − 2 holding for any robot. [ABSTRACT FROM AUTHOR]

In this paper some new results on edge coloring of graphs are introduced. This paper deals mainly with edge cover coloring, g-edge cover coloring, (g, f)-coloring and equitable edge coloring. Some new problems and conjectures are presented. [ABSTRACT FROM AUTHOR]

Let Pn be a set of n points on the plane in general position, n ≥ 4. A convex quadrangulation of Pn is a partitioning of the convex hull $\mathit{Conv}(P_n)$ of Pn into a set of quadrilaterals such that their vertices are elements of Pn, and no element of Pn lies in the interior of any quadrilateral. It is straightforward to see that if P admits a quadrilaterization, its convex hull must have an even number of vertices. In [6] it was proved that if the convex hull of Pn has an even number of points, then by adding at most $\frac{3n}{2}$ Steiner points in the interior of its convex hull, we can always obtain a point set that admits a convex quadrangulation. The authors also show that $\frac{n}{4}$ Steiner points are sometimes necessary. In this paper we show how to improve the upper and lower bounds of [6] to $\frac{4n}{5}+2$ and to $\frac{n}{3}$ respectively. In fact, in this paper we prove an upper bound of n, and with a long and unenlightening case analysis (over fifty cases!) we can improve the upper bound to $\frac{4n}{5}+2$, for details see [9]. [ABSTRACT FROM AUTHOR]

In this paper we present a method for fast energy minimization of virtual garments. Our method is based upon the idea of multi-resolution particle system. When garments are approximately positioned around a virtual character, their spring energy may be high, which will cause instability or at least long execution time of the simulation. An energy minimization algorithm is needed; if a fixed resolution is used, it will require many iterations to reduce its energy. Even though the complexity of each iteration is O(n), with a high resolution mass-spring system, this minimization process can take a whole day. The hierarchical method presented in this paper is used to reduce significantly the execution time of the minimization process. The garments are firstly discretized in several resolutions. Once the lowest resolution particles system is minimized (in a short time), a higher resolution model is derived, then minimized. The procedure is iterated up to the highest resolution. But at this stage, the energy to minimize is already much lower so that minimization takes a reasonable time. [ABSTRACT FROM AUTHOR]

This paper describes a novel discrimination method of lung cancers based on statistical analysis of thoracic computed tomography (CT) scans. Our previous Computer-Aided Diagnosis (CAD) system can detect lung cancers from CT scans, but, at the same time, yields many false positives. In order to reduce the false positives, the method proposed in the present paper uses a relationship between lung cancers, false positives and image information on CT scans. The trend of variation of the relationships is acquired through statistical analysis of a set of CT scans prepared for training. In testing, by use of the trend, the method predicts the appearance of lung cancers and false positives in a CT scan, and improves the accuracy of the previous CAD system by modifying the system's output based on the prediction. The method is applied to 218 actual thoracic CT scans with 386 actual lung cancers. Receiver operating characteristic (ROC) analysis is used to evaluate the results. The area under the ROC curve (Az) is statistically significantly improved from 0.918 to 0.931. [ABSTRACT FROM AUTHOR]

This paper describes expression space generation technology that enables animators to control the expressions of 3-dimensional avatars in real-time by selecting a series of expressions from facial expression space. In this system, approximately 2400 facial expression frames are used to generate facial expression space. In this paper, distance matrixes that present distances between facial characteristic points are used to show the state of an expression. The set of these distance matrixes is defined as facial expression space. However, this facial expression space is not space that can be transferred to one space or another in a straight line, when one expression changes to another. In this technology, the route for moving from one expression to another is approximately inferred from captured facial expression data. First, it is assumed that two expressions are close to each other when the distance between distance matrixes that show facial expression states is below a certain value. When two random facial expression states are connected with the set of a series of adjacent expressions, it is assumed that there is a route between the two expressions. It is further assumed that the shortest path between two facial expressions is the path when one expression moves to the other expression. Dynamic programming is used to find the shortest path between two facial expressions. The facial expression space, which is the set of these distance matrixes, is multidimensional space. The facial expression control of 3-dimensional avatars is carried out in real-time when animators navigate through facial expression space. In order to assist this task, multidimensional scaling is used for visualization in 2-dimensional space, and animators are told to control facial expressions when using this system. This paper evaluates the results of the experiment. [ABSTRACT FROM AUTHOR]

In this paper, we propose a new gaze estimation method by analyzing the cornea surface model which is estimated through three dimensional analysis of human eye in HMD (Head Mounted Display) environments. This paper has four advantages over previous works. First, in order to obtain accurate gaze position, we use a cornea sphere model based on Gullstrand eye scheme. Second, we calculate the 3D position of the cornea sphere and a gaze vector by using a camera, three collimated IR-LEDs and one illuminated IR-LED. Third, three coordinates such as camera, monitor and eye coordinates are unified, which can simplify the complex 3D converting calculation and allow for calculation of the 3D eye position and gaze position on a HMD monitor. Fourth, a simple user dependent calibration method is proposed by gazing at one position of HMD monitor based on Kappa compensation. Experimental results showed that the average gaze estimation error of the proposed method was 0.89 degrees. [ABSTRACT FROM AUTHOR]

Non-Photorealistic Rendering (NPR) can offer increased concentration and familiarity to the watcher. For this reason, many media such as movies, games, and commercials currently use the NPR method to deliver information. In this paper, we suggest an interactive system for video cartooning based on the mean-shift segmentation of image and video. In order to solve the problems of time complexity and memory allocation, the conventional problems of video mean-shift segmentation, this paper proposes several techniques such as foreground object based segmentation and sequential segmentation. We also propose the interactive correction technique to get enhanced results. For more cartoonic representation, we used spline curve approximation of segment boundaries in the final rendering results. With our method, we can easily create cartoon rendering output using the video streams such like home video, which can be obtained easily in our daily life. [ABSTRACT FROM AUTHOR]

In certain classes of chemical reaction networks (CRN), there may be two stable states. The challenge is to find a model of the CRN such that the stability properties can be predicted. In this paper we consider the problem of building a P-system designed to simulate the CRN in an attempt to determine if the CRN is stable or bistable. We found that for the networks in [2] none of the bistable CRN would have a bistable P-system by stoichiometry alone. The reaction kinetics must be included in the P-system model; the implementation of which has been considered an open problem. In this paper we conclude that a P-system for a CRN in m reactants and n products has at most 2(m2 + mn) membranes and 6(m2 + mn) rules. This suggests that P-system models of a chemical reaction network, including both stoichiometry and reaction kinetics can be built. [ABSTRACT FROM AUTHOR]

A comprehensive view of speech and voice technologies is now demanding better and more complex tools amenable of extracting as much knowledge about sound and speech as possible. Many knowledge-extraction tasks from speech and voice share well-known procedures at the algorithmic level under the point of view of bio-inspiration. The same resources employed to decode speech phones may be used in the characterization of the speaker (gender, age, speaking group, etc.). Based on these facts the present paper examines a hierarchy of sound processing levels at the auditory and perceptual levels on the brain neural paths which can be translated into a bio-inspired audio-processing architecture. Through this paper its fundamental characteristics are analyzed in relation with current tendencies in cognitive audio processing. Examples extracted from speech processing applications in the domain of acoustic-phonetics are presented. These may find applicability in speaker's characterization, forensics, and biometry, among others. [ABSTRACT FROM AUTHOR]

We consider an extensional version, called qmTT, of the intensional Minimal Type Theory mTT, introduced in a previous paper with G. Sambin, enriched with proof-irrelevance of propositions and effective quotient sets. Then, by using the construction of total setoid à la Bishop we build a model of qmTT over mTT. The design of an extensional type theory with quotients and its interpretation in mTT is a key technical step in order to build a two level system to serve as a minimal foundation for constructive mathematics as advocated in the mentioned paper about mTT. [ABSTRACT FROM AUTHOR]

In this paper, we present the Deployment Support Network (DSN), a new methodology for developing and testing wireless sensor networks (WSN) in a realistic environment. With an additional wireless backbone network a deployed WSN can be observed, controlled, and reprogrammed completely over the air. The DSN provides visibility and control in a similar way as existing emulation testbeds, but overcomes the limitations of wired infrastructures. As a result, development and experiments can be conducted with realistic in- and outdoor deployments. The paper describes the new concept and methodology. Additionally, an architecture-independent implementation of the toolkit is presented, which has been used in an industrial case-study. [ABSTRACT FROM AUTHOR]

The Shortest Common Supersequence Problem (SCSP) is a well-known hard combinatorial optimization problem that formalizes many real world problems. This paper presents a novel randomized search strategy, called probabilistic beam search (PBS), based on the hybridization between beam search and greedy constructive heuristics. PBS is competitive (and sometimes better than) previous state-of-the-art algorithms for solving the SCSP. The paper describes PBS and provides an experimental analysis (including comparisons with previous approaches) that demonstrate its usefulness. [ABSTRACT FROM AUTHOR]

Spam is commonly defined as unsolicited email messages and the goal of spam filtering is to distinguish between spam and legitimate email messages. Much work has been done to filter spam from legitimate emails using machine learning algorithm and substantial performance has been achieved with some amount of false positive (FP) tradeoffs. In the case of spam detection FP problem is unacceptable sometimes. In this paper, an adaptive spam filtering model has been proposed based on Machine learning (ML) algorithms which will get better accuracy by reducing FP problems. This model consists of individual and combined filtering approach from existing well known ML algorithms. The proposed model considers both individual and collective output and analyzes them by an analyzer. A dynamic feature selection (DFS) technique also proposed in this paper for getting better accuracy. [ABSTRACT FROM AUTHOR]

Availability of computer resources is key factor limiting use of bioinformatics analyses as a result of the growing computational demands. Grid computing provides a way to meet these requirements. But it is complicated to build a grid for users. This paper describes an approach to solve this problem using Grid Service technologies. Building the grid based on accepted standards and platforms makes the development and deployment of the grid much easier. A bioinformatics grid computing environment (BioGrid) which consists of the distributed computing application for bioinformatics is presented in this paper. Based on this environment, we propose the architecture of bioinformatics applications which is delivered using Grid Services constructed with the Globus Toolkit 4. We developed a simple program which is defined as the client-server application with grid services. It provides users an approach of grid services to impose grid resources and customize their own grid applications. [ABSTRACT FROM AUTHOR]

Separated grid systems are becoming the new information islands when more and more grid systems are deployed. Grid interoperation is a direction to solve that problem. This paper introduces the implementation of data interoperation between ChinaGrid and SRB. The data interoperation between them is divided into two parts: data access from SRB to ChinaGrid and from ChinaGrid to SRB. Also this paper considers the issues about performance optimization. We get a satisfied experiment result through the optimization measures. [ABSTRACT FROM AUTHOR]

Scale space interest points capture important photometric and deep structure information of an image. The information content of such points can be made explicit using image reconstruction. In this paper we will consider the problem of combining multiple types of interest points used for image reconstruction. It is shown that ordering the complete set of points by differential (quadratic) TV-norm (which works for single feature types) does not yield optimal results for combined point sets. The paper presents a method to solve this problem using canonical sets of scale space features. Qualitative and quantitative analysis show improved performance over simple ordering of points using the TV-norm. [ABSTRACT FROM AUTHOR]

Yao's classical millionaires' problem is about securely determining whether x > y, given two input values x,y, which are held as private inputs by two parties, respectively. The output x > y becomes known to both parties. In this paper, we consider a variant of Yao's problem in which the inputs x,y as well as the output bit x > y are encrypted. Referring to the framework of secure n-party computation based on threshold homomorphic cryptosystems as put forth by Cramer, Damgård, and Nielsen at Eurocrypt 2001, we develop solutions for integer comparison, which take as input two lists of encrypted bits representing x and y, respectively, and produce an encrypted bit indicating whether x > y as output. Secure integer comparison is an important building block for applications such as secure auctions. In this paper, our focus is on the two-party case, although most of our results extend to the multi-party case. We propose new logarithmic-round and constant-round protocols for this setting, which achieve simultaneously very low communication and computational complexities. We analyze the protocols in detail and show that our solutions compare favorably to other known solutions. [ABSTRACT FROM AUTHOR]

Multivariate Cryptography has been an active line of research for almost twenty years. While most multivariate cryptosystems have been under attack, variations of the basic schemes came up as potential repairs. In this paper, we study the Internal Perturbation variation of HFE recently proposed by Ding and Schmidt. Although several results indicate that HFE is vulnerable against algebraic attacks for moderate size parameters, Ding and Schmidt claim that the cryptosystem with internal perturbation should be immune against them. However in this paper, we apply the recently discovered method of differential analysis to the Internal Perturbation of HFE and we find a subtle property which allows to disclose the kernel of the perturbation. Once this has been achieved, the public key can be inverted by attacking the underlying HFE provided the parameters were taken low enough to make the perturbed scheme of competitive performance. [ABSTRACT FROM AUTHOR]

This paper reviews the recent use of genetic programming to automatically synthesize human-competitive designs of complex structures in six engineering domains, namely analog electrical circuits, optical lens systems, controllers, antennas, mechanical systems, and quantum computing circuits. First, the paper identifies common features observed in the human-competitive results produced by genetic programming in the six domains and suggests possible explanations for the observed similarities. Second, the paper identifies the characteristics that make a particular domain amenable to the application of genetic programming for the automatic synthesis of designs. Third, the paper discusses certain domain-specific adjustments in technique that may increase the efficiency of the automated process in a particular domain. Fourth, the paper discusses several technique issues that have arisen in more than one domain. [ABSTRACT FROM AUTHOR]

The Direct Anonymous Attestation (DAA) scheme provides a means for remotely authenticating a trusted platform whilst preserving the user's privacy. The protocol has been adopted by the Trusted Computing Group (TCG) in the latest version of its Trusted Platform Module (TPM) specification. In this paper we show DAA places an unnecessarily large burden on the TPM host. We demonstrate how corrupt administrators can exploit this weakness to violate privacy. The paper provides a fix for the vulnerability. Further privacy issues concerning linkability are identified and a framework for their resolution is developed. In addition an optimisation to reduce the number of messages exchanged is proposed. [ABSTRACT FROM AUTHOR]

Researchers have attempted to explain the power of Genetic Programming (GP) search using various notions of schema. However empirical studies of schemas have been limited due to their vast numbers in typical populations. This paper addresses the problem of analyzing schemas represented by tree-fragments. It describes a new efficient way of representing the huge sets of fragments in a population of GP programs and presents an algorithm to find all fragments using this efficient representation. Using this algorithm, the paper presents an initial analysis of fragments in populations of up to 300 programs, each up to seven nodes deep. The analysis demonstrates a surprisingly large variation in the numbers of fragments through evolution and a non-monotonic rise in the most useful fragments. With his method, empirical investigation of the GP building block hypothesis and schema theory in realistic sized GP systems becomes possible. [ABSTRACT FROM AUTHOR]

The Broadcast Language is a programming formalism devised by Holland in 1975, which aims at improving the efficiency of Genetic Algorithms (GAs) during long-term evolution. The key mechanism of the Broadcast Language is to allow GAs to employ an adaptable problem representation. Fixed problem encoding is commonly used by GAs but may limit their performance in particular cases. This paper describes an implementation of the Broadcast Language and its application to modeling biochemical networks. Holland presented the Broadcast Language in his book "Adaptation in Natural and Artificial Systems" where only a description of the language was provided, without any implementation. Our primary motivation for this work was the fact that there is currently no published implementation of the Broadcast Language available. Secondly, no additional examination of the Broadcast Language and its applications can be found in the literature. Holland proposed that the Broadcast Language would be suitable for the modeling of biochemical models. However, he did not support this belief with any experimental work. In this paper, we propose an implementation of the Broadcast Language which is then applied to the modeling of a signal transduction network. We conclude the paper by proposing that with some refinements it will be possible to use the Broadcast Language to evolve biochemical networks in silico. [ABSTRACT FROM AUTHOR]

This paper presents a Connectivity based Partition Approach (CPA) to reduce the energy consumption of a sensor network by sleep scheduling among sensor nodes. CPA partitions sensors into groups such that a connected backbone network can be maintained by keeping only one arbitrary node from each group in active status while putting others to sleep. Nodes within each group swap between active and sleeping status occasionally to balance the energy consumption. Unlike previous approaches that partition nodes geographically, CPA is based on the measured connectivity between pairwise nodes and does not depend on nodes' locations. In this paper, we formulate node scheduling as a constrained optimal graph partition problem, and propose CPA as a distributed heuristic partition algorithm. CPA can ensure k-vertex connectivity of the backbone network for its partition so as to achieve the trade-off between saving energy and preserving network communication quality. Moreover, simulation results show that CPA outperforms other approaches in complex environments where the ideal radio propagation model does not hold. [ABSTRACT FROM AUTHOR]

In this paper, we consider how to localize individual nodes in a wireless sensor network when some subset of the network nodes can be in motion at any given time. For situations in which it is not practical or cost-efficient to use GPS or anchor nodes, this paper proposes an Anchor-Free Mobile Geographic Distributed Localization (MGDL) algorithm for wireless sensor networks. Taking advantage of the accelerometers that are present in standard motes, MGDL estimates the distance moved by each node. If this distance is beyond a threshold, then this node will trigger a series of mobile localization procedures to recalculate and update its location in the node itself. Such procedures will be stopped when the node stops moving. Data collected using Tmote Invent nodes (Moteiv Inc.) and simulations show that the proposed detection method can efficiently detect the movement, and that the localization is accurate and the communication is efficient in different static and mobile contexts. [ABSTRACT FROM AUTHOR]

Sensor networks are often used to sense the physical world and provide observations for various uses. In hostile environments, it is critical to control the network access to ensure the integrity, availability, and at times confidentiality of the sensor data. This paper develops efficient methods for distributed access control in sensor networks. The paper starts with a baseline approach, which provides a more flexible and efficient way to enforce access control when compared with previous solutions. This paper then extends the baseline approach to enable privilege delegation, which allows a user to delegate its privilege to other users without using a trusted server, and broadcast query, which allows a user to access the network at a large scale efficiently. The privilege delegation and broadcast query are very useful in practice; none of the current solutions can achieve these two properties. [ABSTRACT FROM AUTHOR]

The Majority game is a two player game with a questioner Q and an answerer A. The answerer holds n elements, each of which can be labeled as 0 or 1. The questioner can ask questions comparing whether two elements have the same or different label. The goal for the questioner is to ask as few questions as possible to be able to identify a single element which has a majority label, or in the case of a tie claim there is none. We denote the minimum number of questions Q needs to make, regardless of A's answers, as q*. In this paper we consider a variation of the Majority game where A is allowed to lie up to t times, i.e., Q needs to find an error-tolerant strategy. In this paper we will give upper and lower bounds for q* for an adaptive game (where questions are processed one at a time), and will find q* for an oblivious game (where questions are asked in one batch). [ABSTRACT FROM AUTHOR]

In this paper, we consider the evacuation problem for a network which consists of a directed graph with capacities and transit times on its arcs. This problem can be solved by the algorithm of Hoppe and Tardos [1] in polynomial time. However their running time is high-order polynomial, and hence is not practical in general. Thus it is necessary to devise a faster algorithm for a tractable and practically useful subclass of this problem. In this paper, we consider a dynamic network with a single sink s such that () for each vertex v the sum of transit times of arcs on any path from v to s takes the same value, and () for each vertex v the minimum v-s cut is determined by the arcs incident to s whose tails are reachable from v. We propose an efficient algorithm for this network problem. This class of networks is a generalization of the grid network studied in the paper [2]. [ABSTRACT FROM AUTHOR]

This paper presents an edge detection method based on bilateral filtering taking into account both spatial closeness and intensity similarity of pixels in order to preserve important visual cues provided by edges and reduce the sharpness of transitions in intensity values as well. In addition, the edge detection method proposed in this paper is achieved on sampled images represented on a newly developed virtual hexagonal structure. Due to the compact and circular nature of the hexagonal lattice, a better quality edge map is obtained. We also present a parallel implementation for edge detection on the virtual hexagonal structure that significantly increases the computation speed. [ABSTRACT FROM AUTHOR]

In recent large scale deployment of active RFID systems has been introduced by many applications, but a variety of critical issues remain unresolved. Especially, the impact of collision is the most essential problem. In this paper, we propose a Learning-based Dynamic Framed Slotted ALOHA algorithm (LDFSA) which mitigates collision from the active RFID tags and complies with international standard, ISO/IEC 18000-7. In addition, this paper includes the performance evaluations of the proposed LDFSA algorithm with the conventional algorithms. According to the result, the proposed LDFSA algorithm shows better performance than other conventional algorithms. [ABSTRACT FROM AUTHOR]

As grid infrastructures become more dynamic in order to cope with the uncertainty of demand, they are becoming extremely difficult to manage. At the Belfast e-Science Centre, we are attempting to address this issue by developing Self Managing Grid Middleware. This paper gives an overview of the middleware and focuses on the design, implementation and evaluation of a Resource Manager. Also in this paper we will see how our approach, which is based on federated UDDI registries, has enabled us to implement some of the desired features of next generation grid software. [ABSTRACT FROM AUTHOR]

The trustworthiness between anonymous web service client and provider influences service stability and collaboration. Trustworthiness includes some aspects such as service's security, controllability and survivability. So, a definition of trustworthiness for web service is given in the paper, and then a web service trustworthiness evaluation and management model is brought forth inspired by human small-world network. The model consists of three web service federations: WSRRC, APAEAS and AWSORT. WSRRC is a Web Service Resource Register Center, which is established by UDDI protocol. APAEAS is an Area Proxy Authentication Evaluating Autonomy System, which collects some authentication information of web service clients, accepts clients' special requirement and feedbacks service's trustworthiness values to AWSORT. AWSORT is an Area WS Resource Organizing Tree, which organizes and manages web service resources; records web service trustworthiness values, keeps web service state, assigning web service. The model establishes a trustworthy environment for anonymous web service clients and providers. Furthermore, some detailed evaluating parameters about service trustworthiness and quality is discussed and some service management algorithms are proposed in the paper. The simulation results show that model is feasible for semantic grid integration and establishment for virtual organization. [ABSTRACT FROM AUTHOR]

We present in this paper the recent developments done in P2P-MPI, a grid middleware, concerning the fault management, which covers fault-tolerance for applications and fault detection. P2P-MPI provides a transparent fault tolerance facility based on replication of computations. Applications are monitored by a distributed set of external modules called failure detectors. The contribution of this paper is the analysis of the advantages and drawbacks of such detectors for a real implementation, and its integration in P2P-MPI. We pay especially attention to the reliability of the failure detection service and to the failure detection speed. We propose a variant of the binary round-robin protocol, which is more reliable than the application execution in any case. Experiments on applications of up to 256 processes, carried out on Grid'5000 show that the real detection times closely match the predictions. [ABSTRACT FROM AUTHOR]

In the last years several Grid Virtual Organizations -VOs- have been proliferating, each one usually installing its own Certification Authority and thus giving birth to a large set of different and possibly untrusted security domains. Nevertheless, despite the fact that the adoption of Grid Certification Authorities (CAs) has partially solved the problem of identification and authentication between the involved parties, and that Public Key Infrastructure (PKI) technologies are mature enough, we cannot make the same assumptions when untrusted domains are involved. In this paper we propose an architecture to face the problem of secure interoperability among untrusted Grid-domains. Our approach is based on building a dynamic federation of CAs, formed thorough the quantitative and automatic evaluation of their Certificate Policies. In this paper we describe the proposed architecture and its integration into Globus Toolkit 4. [ABSTRACT FROM AUTHOR]

This paper gives a broad overview of the area of searching with errors and the related field of error-correcting coding. In the vast literature regarding this problem, many papers simultaneously deal with various sorts of restrictions on the searching protocol. We partition this survey into sections, choosing the most appropriate section for each topic. [ABSTRACT FROM AUTHOR]

This paper presents a new precomputation algorithm for Multi Protocol Label Switching (MPLS) traffic engineering routing. The prior MPLS routing algorithms try to minimize the interference between different source-destination pairs by circumventing the critical links. But the process of identifying critical links is very computationally expensive. The main contribution of this paper is a new precomputation approach of route selection considering the interference. The proposed algorithm reduces online computing complexity through efficient precomputation. From the simulation results, the proposed algorithm outperforms prior algorithms in terms of efficiency and complexity. [ABSTRACT FROM AUTHOR]

In the network traffic, the nature of the input output data/signal signals are used to demonstrate the statistical characterization of the traffic performance. Observations of traffic on network links typically reveal intensity levels (in bits/sec) averaged over periods of time periods which are relatively predictable from day to day. Systematic intensity variations occur within the day reflecting user activity. In this paper, the stochastic spectral analysis is performed on the input/output signal signals and the ratio of the spectral power of the output and input signals are taken as the characteristics of the statistical nature of the network traffic. For different time averaging schemes this characteristic ratio shows a bounded nature. In this paper the theoretical analysis is done on the boundedness of the characteristics ratio through the process of stochastic spectral density analysis. Keywords: Network traffic, stochastic spectral power. [ABSTRACT FROM AUTHOR]

This paper describes the invited talk given at the 8th International Conference on Distributed Computing and Networking (ICDCN 2006), at the Indian Institute of Technology Guwahati, India. This talk was intended to give a partial survey and to motivate further studies of distributed verification. To serve the purpose of motivating, we allow ourselves to speculate freely on the potential impact of such research. In the context of sequential computing, it is common to assume that the task of verifying a property of an object may be much easier than computing it (consider, for example, solving an NP-Complete problem versus verifying a witness). Extrapolating from the impact the separation of these two notions (computing and verifying) had in the context of sequential computing, the separation may prove to have a profound impact on the field of distributed computing as well. In addition, in the context of distributed computing, the motivation for the separation seems even stronger than in the centralized sequential case. In this paper we explain some motivations for specific definitions, survey some very related notions and their motivations in the literature, survey some examples for problems and solutions, and mention some additional general results such as general algorithmic methods and general lower bounds. Since this paper is mostly intended to "give a taste" rather than be a comprehensive survey, we apologize to authors of additional related papers that we did not mention or detailed. [ABSTRACT FROM AUTHOR]

The crossing number of a graph G is the smallest number of edge crossings in any drawing of G into the plane. Recently, the first branch-and-cut approach for solving the crossing number problem has been presented in [3]. Its major drawback was the huge number of variables out of which only very few were actually used in the optimal solution. This restricted the algorithm to rather small graphs with low crossing number. In this paper we discuss two column generation schemes; the first is based on traditional algebraic pricing, and the second uses combinatorial arguments to decide whether and which variables need to be added. The main focus of this paper is the experimental comparison between the original approach, and these two schemes. We also compare these new results to the solutions of the best known crossing number heuristic. [ABSTRACT FROM AUTHOR]

In voting systems, game theory, switching functions, threshold logic, hypergraphs or coherent structures there is an important problem that consists in determining the weightedness of a voting system by means of trades among voters in sets of coalitions. The fundamental theorem by Taylor and Zwicker [8] establishes the equivalence between weighted voting games and k-trade robust games for each positive integer k. Moreover, they also construct, in [9], a succession of games Gk based on magic squares which are (k - 1)-trade robust but not k-trade robust, each one of these games Gk has k2 players. The goal of this paper is to provide improvements by means of different experiments to the problem described above. In particular, we will classify all complete games (a basic class of games) of less than eight players according to whether they are: a weighted voting game or a game which is (k - 1)-trade robust but not k-trade robust for all values of k. As a consequence it will we showed the existence of games with less than k2 players which are (k - 1)-trade robust but not k-trade robust. We want to point out that the classifications obtained in this paper by means of experiments are new in the mentioned fields. [ABSTRACT FROM AUTHOR]

This paper describes a detailed study of a recursive search algorithm for different optimization problems. Although the algorithm has been originally developed for a project scheduling problem with financial objectives, we show that it can be extended to many other application areas and therefore, can serve as a sub-procedure for various optimization problems. The contribution of the paper is threefold. First, we present a hybrid recursive search procedure for the project scheduling problem with net present value maximization and compare it with state-of-the-art procedures by means of computational tests. Second, we show how the procedure can be adapted to two other application areas: project scheduling with work continuity minimization and the open pit mining problem. Last, we highlight some future research areas where this hybrid procedure might bring a promising contribution. [ABSTRACT FROM AUTHOR]

This paper proposes an evolutionary algorithm (EA) that is applied to the traveling salesman problem (TSP). Existing approximation methods to address the TSP known to be state-of-the-art heuristics almost exclusively utilize Lin-Kernighan local search (LKLS) and its variants. We propose an EA that does not use LKLS, and demonstrate that it is comparable with these heuristics even though it does not use them. The proposed EA uses edge assembly crossover (EAX) that is known to be an efficient and effective crossover for solving TSPs. We first propose a modified EAX algorithm that can be executed more efficiently than the original, which is 2-7 times faster. We then propose a selection model that can efficiently maintain population diversity at negligible computational cost. The edge entropy measure is used as an indicator of population diversity. The proposed method called EAX-1AB(ENT) is applied to TSP benchmarks up to instances of 13509 cities. Experimental results reveal that EAX-1AB(ENT) with a population of 200 can almost always find optimal solutions effectively in most TSP benchmarks up to instances of 5915 cities. In the experiments, a previously proposed EAs using EAX can find an optimal solution of usa13509 with reasonable computational cost due to the fast EAX algorithm proposed in this paper. We also demonstrate that EAX-1AB(ENT) is comparable to well-known LKLS methods when relatively small populations such as 30 are used. [ABSTRACT FROM AUTHOR]