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Often the ownership of the information exchanged in IoT environments is protected by watermarking. Violations are tracked by enforcing, at a cost, a watermarking verification procedure. Due to this cost and other practical limits, the procedure cannot be exhaustively applied to all the information exchanged: this limit can be exploited by malicious agents. In this work, we model the watermark falsification and the watermark verification process, under classical Game Theory assumptions, as a three-player inspection game: the players are the legitimate owner of the information, or licensee, the potential illegitimate holder of the information (the peers) and an inspector. We compute the rate of violation of the rule and the rate of inspection at equilibrium. We also compare the game with similar three player inspection games and show that, under the adopted assumptions, the two peers do not have any incentive in setting up a coalition.

International audience; A challenge in designing cooperative distributed systems is to develop feasible and cost-effective mechanisms to foster 7 cooperation among selfish nodes, i.e., nodes that strategically deviate from the intended specification to increase their individual utility. 8 Finding a satisfactory solution to this challenge may be complicated by the intrinsic characteristics of each system, as well as by the 9 particular objectives set by the system designer. Our previous work addressed this challenge by proposing RACOON, a general and 10 semi-automatic framework for designing selfishness-resilient cooperative systems. RACOON relies on classical game theory and a 11 custom built simulator to predict the impact of a fixed set of selfish behaviours on the designer's objectives. In this paper, we present 12 RACOON++, which extends the previous framework with a declarative model for defining the utility function and the static behaviour of 13 selfish nodes, along with a new model for reasoning on the dynamic interactions of nodes, based on evolutionary game theory. We 14 illustrate the benefits of using RACOON++ by designing three cooperative systems: a peer-to-peer live streaming system, a load 15 balancing protocol, and an anonymous communication system. Extensive experimental results using the state-of-the-art PeerSim 16 simulator verify that the systems designed using RACOON++ achieve both selfishness-resilience and high performance.

We study the denoising and reconstruction of corrupted signals by means of AutoEncoder ensembles. In order to guarantee experts’ diversity in the ensemble, we apply, prior to learning, a dimensional reduction pass (to map the examples into a suitable Euclidean space) and a partitional clustering pass: each cluster is then used to train a distinct AutoEncoder. We study the approach with an audio file benchmark: the original signals are artificially corrupted by Doppler effect and reverb. The results support the comparative effectiveness of the approach, w.r.t. the approach based on a single AutoEncoder. The processing pipeline using Local Linear Embedding, k means, then k Convolutional Denoising AutoEncoders reduces the reconstruction error by 35% w.r.t. the baseline approach.

We investigate the hypothesis that long-term memory in populations of agents can lead to counterproductive emergent properties at the system level. Our investigation is framed in the context of a discrete, one-dimensional road-traffic congestion model: we investigate the influence of simple cognition in a population of rational commuter agents that use memory to optimise their departure time, taking into account congestion delays on previous trips. Our results differ from the well-known minority game in that crowded slots do not carry any explicit penalty. We use Markov chain analysis to uncover fundamental properties of this model and then use the gained insight as a benchmark. Then, using Monte Carlo simulations, we study two scenarios: one in which “myopic” agents only remember the outcome (delay) of their latest commute, and one in which their memory is practically infinite. We show that there exists a trade-off, whereby myopic memory reduces congestion but increases uncertainty, while infinite memory does the opposite. We evaluate the performance against the optimal distribution of departure times (i.e. where both delay and uncertainty are minimised simultaneously). This optimal but unstable distribution is identified using a genetic algorithm., SCOPUS: ar.j, info:eu-repo/semantics/published

Traditional authentication systems use alphanumeric or graphical passwords, or token-based techniques that require "something you know and something you have". The disadvantages of these systems include the risks of forgetfulness, loss, and theft. To address these shortcomings, biometric authentication is rapidly replacing traditional authentication methods and is becoming a part of everyday life. The electrocardiogram (ECG) is one of the most recent traits considered for biometric purposes. In this work we describe an ECG-based authentication system suitable for security checks and hospital environments. The proposed system will help investigators studying ECG-based biometric authentication techniques to define dataset boundaries and to acquire high-quality training data. We evaluated the performance of the proposed system and found that it could achieve up to the 92 percent identification accuracy. In addition, by applying the Amang ECG (amgecg) toolbox within MATLAB, we investigated the two parameters that directly affect the accuracy of authentication: the ECG slicing time (sliding window) and the sampling time period, and found their optimal values., Comment: This paper has been published in the IEEE Access

In contrast to single-view learning, multi-view learning trains simultaneously distinct algorithms on disjoint subsets of features (the views), and jointly optimizes them, so that they come to a consensus. Multi-view learning is typically used when the data are described by a large number of features. It aims at exploiting the different statistical properties of distinct views. A task to be performed before multi-view learning – in the case where the features have no natural groupings – is multi-view generation (MVG): it consists in partitioning the feature set in subsets (views) characterized by some desired properties. Given a dataset, in the form of a table with a large number of columns, the desired solution of the MVG problem is a partition of the columns that optimizes an objective function, encoding typical requirements. If the class labels are available, one wants to minimize the inter-view redundancy in target prediction and maximize consistency. If the class labels are not available, one wants simply to minimize inter-view redundancy (minimize the information each view has about the others). In this work, we approach the MVG problem in the latter, unsupervised, setting. Our approach is based on the transposition of the data table: the original instance rows are mapped into columns (the "pseudo-features"), while the original feature columns become rows (the "pseudo-instances"). The latter can then be partitioned by any suitable standard instance-partitioning algorithm: the resulting groups can be considered as groups of the original features, i.e. views, solution of the MVG problem. We demonstrate the approach using k-means and the standard benchmark MNIST dataset of handwritten digits.

The Retinex algorithm, developed by Land and McCann, provides an abstract model of the mechanism of color sensation in the Human Vision System. At the basis of model lies the fact that the color appearance of a point does not depend only on its color value, but rather on the comparison among itself and other pixels. According to the model, separately for each chromatic channel, an image pixel receives suitably filtered information about the brightness of other image regions, based on which its own brightness is eventually re-scaled. The original formulation (Land and McCann, 1971) uses a path-based sampling approach: the information is transported by memoryless random walks, starting from randomly chosen points; along the path the information is filtered - based on the brightness of the travelled regions - by a specific path function, computed through chains of ratios of pixel intensities. Such a function is path-dependent and retains the value of the brightest point found along the path. The overall correction to a pixel depends on the specific realizations of two sampling processes: the starting-point sampling process and the path-sampling process. As a consequence of the sampling, this algorithm is known to be intrinsically noisy. This draw-back can be overcome by passing from the path-sampling algorithm to the probabilistic representation of the corresponding diffusion process. In this paper we start from the random path simulative model of Retinex, we respell the standard path-based sampling process representation of the Retinex model, as formalized in Provenzi et?al. (2005), and we show that - despite the overall path-dependence - the model can be given a representation in terms of Absorbing Markov Chains, by means of the embedding into a suitable state-space. We derive the corresponding analytic model, accounting for the combined effects of path-function, path sampling process and starting-point sampling process. Finally we provide a numerical algorithm for working out its solution. Using such a model, the output brightness of a pixel can be computed based on the solution of a simple sparse linear system. We show that the output of the random walk sampling algorithm and the Markov Chain based algorithm agree to an extent that can be controlled by few model parameters. We have found also that the Markov Chain based algorithm is more efficient than the basic random path sampling in obtaining noise free images. Those analytic probabilistic models and simulative models can be used as complementary tools for studying the Retinex mechanism and for identifying and comparing variants.

Current cloud assurance standards aren't a substitute for continual risk monitoring, especially when insider threats are concerned. Microeconomic analysis of business processes can offer a novel perspective toward fully quantitative by-process assessment of threats to confidentiality.

In order to keep in good long-term relationships with their main customers, Airline Cargo companies do not impose any fee for last minute cancellations of shipments. As a result, customers can book the same shipment on several cargo companies. Cargo companies try to balance cancellations by a corresponding volume of overbooking. However, the considerable uncertainty in the number of cancellations does not allow to fine-tune the optimal overbooking level, causing losses. In this work, we show how the deployment of cryptographic techniques, enabling the computation on private information of customers and companies data can improve the overall service chain, allowing for striking and enforcing better agreements. We propose a query system based on proxy re-encryption and show how the relevant information can be extracted, still preserving the privacy of customers’ data. Furthermore, we provide a Game Theoretic model of the use case scenario and show that it allows a more accurate estimate of the cancellation rates. This supports the reduction of the uncertainty and allows to better tune the overbooking level.

Glare is always present in optical acquisition systems, such as photocameras or the eye-bulb. As a consequence, images captured by sensors do not represent an accurate reproduction of the scene, but rather a combination of scene content and glare. We discuss the reasons why this unwanted addition of spread light cannot be removed from an acquired image. To this aim, we cast the problem of glare-removal into an estimation task and focus on the aspects that make the unfolding of glare an ill-posed or ill-conditioned problem—such as nonlinearity, information loss, or eye model uncertainty. For each mechanism of glare formation, we point to the corresponding influence in terms of ill-posedness and ill-conditioning of the problem. We do not aim at proposing or reviewing solutions to the glare problem but rather at identifying more precisely the challenges it poses.

Boolean classifiers can be evolved by means of genetic algorithms. This can be done within an intercommunicating island system, of evolutionary niches, undergoing cycles that alternate long periods of isolation to short periods of information exchange. In these settings, the efficiency of the communication is a key requirement. In the present work, we address this requirement by providing a technique for efficiently representing and transmitting differential encodings of Boolean functions. We introduce a new class of Boolean Neural Networks (BNN), the all-implicants BNN, and show that this representation supports efficient update communication, better than the classical representation, based on truth tables.

International audience; Selfishness is one of the key problems that confronts developers of cooperative distributed systems (e.g., file-sharing networks, voluntary computing). It has the potential to severely degrade system performance and to lead to instability and failures. Current techniques for understanding the impact of selfish behaviours and designing effective countermeasures remain manual and time-consuming, requiring multi-domain expertise. To overcome these difficulties, we propose SEINE, a simulation framework for rapid modelling and evaluation of selfish behaviours in a cooperative system. SEINE relies on a domain-specific language (SEINE-L) for specifying selfishness scenarios, and provides semi-automatic support for their implementation and study in a state-of-the-art simulator. We show in this paper that (1) SEINE-L is expressive enough to specify fifteen selfishness scenarios taken from the literature, (2) SEINE is accurate in predicting the impact of selfishness compared to real experiments, and (3) SEINE substantially reduces the development effort compared to traditional manual approaches.

In multi-authority Wireless Sensor Networks, governed by different authorities, resource constrained a node may be reluctant to forward packets received from other collaborating authorities, so as to save its own resources. If adopted by a significant percentage of nodes, such behavior can affect network performance and may reduce the service time of each node. To investigate such sensor nodes behavior, we used an Evolutionary Game Theory (EGT) approach. We studied a model of the system based on incentives and evolved the system according to standard replicator dynamics. We observed the emergence of a collaborative equilibrium. Based on this we designed a cluster based Collaborative Packets Forwarding (CPF) algorithm and showed by simulation that it is able to extend network lifetime.

Folksonomies - Les reseaux sociaux, les ressources disponibles sur le web et les tags utilisateurs qui y sont associes permettent de facilement recuperer, organiser du contenu et naviguer sur le web. Cependant, leurs avantages restent limites, principalement a cause du caractere bruite des tags proposes par les utilisateurs. Pour pallier cette difficulte, nous proposons une methode pour regrouper les tags similaires dans une folksonomie : les cooccurrences entre tags et le "Laplacian Score" sont utilisees pour definir, pour chaque tag, une distribution de probabilite empirique ; les tags supposes lies sont identifies selon les similarites entre leurs distributions. Dans ce but, nous presentons une variante de la divergence de Jensen-Shannon, plus resistante au bruit. Nous evaluons notre approche experimentalement a l’aide de WordNet et la comparons a une methode classique de recherche de similarite entre tags, basee sur la similarite cosinus. Les resultats de notre evaluation montrent l’efficacite de notre approche et ses avantages par rapport aux methodes concurrentes.

The human color sensation depends on the local and global spatial arrangements of the colors in the scene. Emulating this dependence requires the exploration of the image in search of a white reference. The algorithm Termite Retinex explores the image by a set of paths resembling traces of a swarm of termites. Starting from this approach, we develop a novel spatial exploration scheme where the termite paths are local minimums of an energy function, which depend on the image visual content. The energy is designed to favor the visitation of regions containing information relevant to the color sensation while minimizing the coverage of less essential regions. This exploration method contributes to the investigation of the spatial properties of the color sensation and, to the best of our knowledge, is the first model relying on mathematical global conditions for the Retinex paths. The experiments show that the estimation of the color sensation obtained by means of the proposed spatial sampling is a valid alternative to the one based on Termite Retinex.

In tag-word disambiguation, a word is assigned to a specific context chosen among the different ones to which it is related. Relatedness to a context is often defined based on the co-occurrence of the target word with other words (context words) in sentences of a specific corpus. The overall disambiguation process can be thought as a classification process, where the context words play the role of features for the target. A problem with this approach is that the large number of possible context words can reduce the classification performance, both in terms of computational effort and in terms of quality of the outcome. Feature selection can improve the process in both regards, by reducing the overall feature space to a manageable size with high information content. In this work we propose to use, in disambiguation, a feature selection approach based on the Shapley Value (SV) - a Coalitional Game Theory related metrics, measuring the importance of a component within a coalition. By including in the feature set only the words with the highest Shapley Value, we obtain remarkable quality and performance improvements. The problem of the exponential complexity in the exact SV computation is avoided by an approximate computation based on sampling. We demonstrate the effectiveness of this method and of the sampling approach results, by using both a synthetic language corpus and a real world linguistic corpus.

Although tagging simplifies resource browsing and retrieval, it suffers from several issues: among them are redundancy and ambiguity. In this work we focus on the problem of resolving tag word-sense ambiguity within a typical semi-automatic tagging procedure. In that process a user proposes a tag for a resource, if the tag is found to be related to more than one context, she is provided with two or more cues among which to choose, so as to remove the tag ambiguity. Key phases, in such a disambiguation procedure, are ambiguous tag detection and cue discovery. Both should rely on effective word-to-context relatedness metrics. Among the most effective relatedness metrics are those defined on the basis of a feature vector representation of the words. In this work we compare different word-to-context relatedness metrics in terms of effectiveness within the disambiguation process. We propose to use a metrics derived from a Maximum Likelihood estimator of the Jensen-Shannon Divergence among feature-count histograms and we show that such a metrics performs -- in terms of quality of the output -- better than both the Jensen-Shannon and the Symmetrized Kullback-Leibler divergence between histograms. We study the relative gain in quality within the task of unsupervised cue discovery by using a synthetic language corpus.

In unstructured networks, gossiping protocols prescribe that a message, received by a node, is not forwarded with certainty to all its neighbors (as happens in flooding protocols), but only with some finite probability. Typically, in order to make the protocol adaptive, the packet forwarding probability is computed on the fly, as a function of the current node's degree, taken as an indicator of the node's capability of propagating information. This approach improves over flooding protocols, by reducing the traffic overhead, however it is plagued by a problem called early gossip termination, which occurs when the information propagation stops, before the message has reached all the intended target nodes. In the present work, we argue that early gossip termination takes place because the node degree is an inaccurate estimator of the information propagation capability of the node. Specifically: in those cases where this capability happens to be overestimated, the forwarding probability gets set to an insufficient value, which causes information propagation to fade out too early. We propose an approach relying on two interrelated prescriptions, which, being based on the local topological structure of the network, help in better quantifying the information propagation capability of a node. The first prescription consists in using, in place of the actual node degree, an effective node degree, defined on the basis of the nearest neighbors' degree information. The second prescription consists in taking into account the node clustering coefficient to identify special topological situations, which deserve specific treatment. We validated our approach by simulation, using ns2 in several operational scenarios: the results show that the approach can yield significant performance improvements.

Using data from FOCUS (E831) experiment at Fermilab, we present a model independent partial-wave analysis of the K{sup -}{pi}{sup +} S-wave amplitude from the decay D{sup +} {yields} K{sup -}{pi}{sup +}{pi}{sup +}. The S-wave is a generic complex function to be determined directly from the data fit. The P- and D-waves are parameterized by a sum of Breit-Wigner amplitudes. The measurement of the S-wave amplitude covers the whole elastic range of the K{sup -}{pi}{sup +} system.

Mobile network providers have developed a variety of location-based services (LBSs), such as friend-finder, point of interest services, emergency rescue and many other safety and security services. The protection of location-privacy has consequently become a key aspect to the success of LBSs, since users consider their own physical location and movements highly privacy-sensitive, and demand for solutions able to protect such an information in a variety of environments. The idea behind location-privacy protection is that the individual should be able to set the level at which the location information is released to avoid undesired exploitation by a potential attacker: one of the approaches to this problem is given by the application of spatial obfuscation techniques, actuated by a trusted agent, and consisting in artificial perturbations of the location information collected by sensing technologies, before its disclosure to third parties. In many situations, however, landscape/map information can help a third party to perform Bayesian inference over spatially obfuscated data and to refine the user's location estimate up to a violation of the original user's location-privacy requirements. The goal of this paper is to provide a map-dependent obfuscation procedure that enables the release of the maximum possible user's location information, that does not lead to a violation of the original user's location-privacy requirements, even when refined through map-based inference.

We present a search for a pentaquark decaying strongly to $\Xi^-\pi^-$ in $\gamma N$ collisions at a center-of-mass energy up to 25 GeV/c^2. Finding no evidence for such a state in the mass range of 1480 MeV/c^2 to 2400 MeV/c^2, we set limits on the yield and on the cross section times branching ratio relative to $\Xi^*(1530)^0$.

We study the decay of D s + mesons into final states involving a K S 0 and report the discovery of Cabibbo suppressed decay modes D s + → K S 0 π − π + π + ( 179 ± 36 events) and D s + → K S 0 π + ( 113 ± 26 events). The branching fraction ratios for the new modes are Γ ( D s + → K S 0 π − π + π + ) Γ ( D s + → K S 0 K − π + π + ) = 0.18 ± 0.04 ± 0.05 and Γ ( D s + → K S 0 π + ) Γ ( D s + → K S 0 K + ) = 0.104 ± 0.024 ± 0.014 .

Using data collected by the high energy photoproduction experiment FOCUS at Fermilab we performed a Dalitz plot analysis of the Cabibbo favored decay D{sup +} {yields} K{sup -}{pi}{sup +}{pi}{sup +}. This study uses 53653 Dalitz-plot events with a signal fraction of {approx} 97%, and represents the highest statistics, most complete Dalitz plot analysis for this channel. Results are presented and discussed using two different formalisms. The first is a simple sum of Breit-Wigner functions with freely fitted masses and widths. It is the model traditionally adopted and serves as comparison with the already published analyses. The second uses a K-matrix approach for the dominant S-wave, in which the parameters are fixed by first fitting K{pi} scattering data and continued to threshold by Chiral Perturbation Theory. We show that the Dalitz plot distribution for this decay is consistent with the assumption of two body dominance of the final state interactions and the description of these interactions is in agreement with other data on the K{pi} final state.

Using a large sample of D{sup +} {yields} K{sup -}K{sup +}{pi}{sup +} decays collected by the FOCUS photoproduction experiment at Fermilab, we present the first non-parametric analysis of the K{sup -}{pi}{sup +} amplitudes in D{sup +} {yields} K{sup -}K{sup +}{pi}{sup +} decay. The technique is similar to the technique used for our non-parametric measurements of the D{sup +} {yields} {bar K}*{sup 0} e{sup +}{nu} form factors. Although these results are in rough agreement with those of E687, we observe a wider S-wave contribution for the {bar K}*{sub 0}{sup 0}(1430) contribution than the standard, PDG [1] Breit-Wigner parameterization. We have some weaker evidence for the existence of a new, D-wave component at low values of the K{sup -}{pi}{sup +} mass.

International audience; A challenge in designing a peer-to-peer (P2P) system is to ensure that the system is able to tolerate selfish nodes that strategically deviate from their specification whenever doing so is convenient. In this paper, we propose RACOON, a framework for the design of P2P systems that are resilient to selfish behaviours. While most existing solutions target specific systems or types of selfishness, RACOON proposes a generic and semi-automatic approach that achieves robust and reusable results. Also, RACOON supports the system designer in the performance-oriented tuning of the system, by proposing a novel approach that combines Game Theory and simulations. We illustrate the benefits of using RACOON by designing two P2P systems: a live streaming and an anonymous communication system. In simulations and a real deployment of the two applications on a testbed comprising 100 nodes, the systems designed using RACOON achieve both resilience to selfish nodes and high performance.

Patching vulnerabilities is one of the key activities in security management. For most commercial systems however the number of relevant vulnerabilities is very high; as a consequence only a subset of them can be actually fixed: due to bounded resources, choosing them according to some optimal criterium is a critical challenge for the security manager. One has also to take into account, though, that even delivering attacks on vulnerabilities requires a non-negligible effort: also a potential attacker will always be constrained by bounded resources. Choosing which vulnerabilities to attack according to some optimality criterium is also a difficult challenge for a hacker. Here we argue that if both types of players are rational, wishing to maximize their ROI and aware of the two sides of the problem, their respective strategies can be discussed more naturally within a Game Theory (GT) framework. We develop the fact that the above described attack/defense scenario can be mapped onto a variant of GT models known as Search Games: we call this variant Enhanced Vulnerability Patching game. Under the hypothesis of rationality of the players, GT provides a prediction for their behavior in terms of a probability distribution over the possible choices: this result can help in supporting a semi-automatic choice of patch management with constrained resources. In this work we model and solve few prototypical instances of this class of games and outline the path towards more realistic and accurate GT models.

This work adresses the problem estimating correlations between process observables and KPI/SLA violation metrics. This analysis is aimed at providing business process owners with a suggestion of potential causality between groups of process parameters and violations. Obviously, static regression analysis cannot establish causality. We introduce a notion of Behavioral Analysis of business process instances and argue that, under suitable assumptions, Granger correlation can be used to highlight potential causality between business process observables and violations of leading KPIs. To handle the combinatorial explosion of the process observables search space, we describe a game theoretical approach for identifying (sets of) time-shifted process attributes to be tested.

In this paper, we introduce a novel probabilistic version of retinex. It is based on a probabilistic formalization of the random spray retinex sampling and contributes to the investigation of the spatial properties of the model. Various versions available of the retinex algorithm are characterized by different procedures for exploring the image content (so as to obtain, for each pixel, a reference white value), then used to rescale the pixel lightness. Here we propose an alternative procedure, which computes the reference white value from the percentile values of the pixel population. We formalize two versions of the algorithm: one with global and one with local behavior, characterized by different computational costs.

Business and recreational activities on the global communication infrastructure are increasingly based on the use of remote resources and services, and on the interaction between different, remotely located parties. In such a context, Single Sign-On technologies simplify the log-on process allowing automatic access to secondary domains through a unique log-on operation to the primary domain. In this article, we evaluate different Single Sign-On implementations focusing on the central role of Open Source in the development of Web-based systems. We outline requirements for Single Sign-On systems and evaluate four existing Open Source implementations in terms of degree of fulfilment of those requirements. Finally we compare those Open Source systems with respect to some specific Open Source community patterns.

Using data collected by the FOCUS experiment at Fermilab, we present a new measurement of the charm semileptonic branching ratio BR ( D + → ρ 0 μ + ν ) BR ( D + → K ¯ ∗ 0 μ + ν ) . From a sample of 320 ± 44 and 11372 ± 161 D + → ρ 0 μ + ν and D + → K − π + μ + ν events respectively, we find BR ( D + → ρ 0 μ + ν ) BR ( D + → K ¯ ∗ 0 μ + ν ) = 0.041 ± 0.006 ( stat ) ± 0.004 ( syst ) .

Using data from the FOCUS (E831) experiment at Fermilab, we present a new measurement of the weak decay-asymmetry parameter α Λ c in Λ c + → Λ π + decay. Comparing particle with antiparticle decays, we obtain the first measurement of the CP violation parameter A ≡ α Λ c + α Λ ¯ c α Λ c − α Λ ¯ c . We obtain α Λ c = − 0.78 ± 0.16 ± 0.19 and A = − 0.07 ± 0.19 ± 0.24 where errors are statistical and systematic.

Using a large sample of D + → K − π + μ + ν decays collected by the FOCUS photoproduction experiment at Fermilab, we present the first measurements of the helicity basis form factors free from the assumption of spectroscopic pole dominance. We also present the first information on the form factor that controls the s -wave interference discussed in a previous paper by the FOCUS Collaboration. We find reasonable agreement with the usual assumption of spectroscopic pole dominance and measured form factor ratios.

We review genetic programming principles, their application to FOCUS data samples, and use the method to study the doubly Cabibbo suppressed decay D+ -> K+ pi+ pi- relative to its Cabibbo favored counterpart, D+ -> K- pi+ pi+. We find that this technique is able to improve upon more traditional analysis methods. To our knowledge, this is the first application of the genetic programming technique to High Energy Physics data., 39 pages

We apply a genetic programming technique to search for the doubly Cabibbo suppressed decays Λ c + → p K + π − and D s + → K + K + π − . We normalize these decays to their Cabibbo favored partners and find BR ( Λ c + → p K + π − ) / BR ( Λ c + → p K − π + ) = ( 0.05 ± 0.26 ± 0.02 ) % and BR ( D s + → K + K + π − ) / BR ( D s + → K − K + π + ) = ( 0.52 ± 0.17 ± 0.11 ) % where the first errors are statistical and the second are systematic. Expressed as 90% confidence levels (CL), we find

Using data from the FOCUS (E831) experiment, we have searched for T violation in charm meson decays using the four-body decay channels $D^0 \to K^-K^+\pi^-\pi^+$, $D^+ \to K^0_SK^+\pi^-\pi^+$, and $D^+_s \to K^0_SK^+\pi^-\pi^+$. The T violation asymmetry is obtained using triple-product correlations and assuming the validity of the CPT theorem. We find the asymmetry values to be $A_Tviol (D^0) = 0.010 \pm 0.057(stat.) \pm 0.037(syst.)$, $A_Tviol (D^+) = 0.023 \pm 0.062(stat.) \pm 0.022(syst.)$, and $A_Tviol (D^+_s) = -0.036 \pm 0.067(stat.) \pm 0.023(syst.)$. Each measurement is consistent with no T violation. New measurements of the CP asymmetries for some of these decay modes are also presented., Comment: 17 pages,6 figures,submitted to Phys.Lett.B

Using data from the FOCUS experiment (FNAL–E831), we study the decay of Λ c + baryons into final states containing a Λ hyperon. The branching fractions of Λ c + into Λ π + , Λ π + π + π − and Λ K ¯ 0 K + relative to that into p K − π + are measured to be 0.217 ± 0.013 ± 0.020 , 0.508 ± 0.024 ± 0.024 and 0.142 ± 0.018 ± 0.022 , respectively. We also report new measurements of Γ ( Λ c + → Σ 0 π + ) Γ ( Λ c + → Λ π + ) = 1.09 ± 0.11 ± 0.19 , Γ ( Λ c + → Σ 0 π + π + π − ) Γ ( Λ c + → Λ π + π + π − ) = 0.26 ± 0.06 ± 0.09 and Γ ( Λ c + → Ξ ( 1690 ) 0 ( Λ K ¯ 0 ) K + ) Γ ( Λ c + → Λ K ¯ 0 K + ) = 0.32 ± 0.10 ± 0.04 . Further, an analysis of the subresonant structure for the Λ c + → Λ π + π + π − decay mode is presented.

Using data from the FOCUS (E831) experiment at Fermilab, the authors present a new measurement for the Cabibbo-suppressed decay mode D{sup 0} {yields} K{sup +}K{sup -}{pi}{sup +}{pi}{sup -}. They measure: {Lambda}(D{sup 0} {yields} K{sup +}K{sup -}{pi}{sup +}{pi}{sup -})/{Lambda}(D{sup 0} {yields} K{sup -}{pi}{sup -}{pi}{sup +}{pi}{sup +}) = 0.0295 {+-} 0.0011 {+-} 0.0008. An amplitude analysis has been performed in order to determine the resonant substructure of this decay mode. The dominant components are the decays D{sup 0} {yields} K{sub 1}(1270){sup +} K{sup -}, D{sup 0} {yields} K{sub 1}(1400){sup +}K{sup -} and D{sup 0} {yields} {rho}(770){sup 0}{phi}(1020).

Using data collected by the fixed target Fermilab experiment FOCUS, we present several first measurements for the semileptonic decay D0→K¯0π−μ+ν. Using a model that includes a K¯0π− s-wave component, we measure the form factor ratios to be rv=1.71±0.68±0.34 and r2=0.91±0.37±0.10 and the s-wave amplitude to be A=0.35±0.22±0.05GeV−1. Finally, we measure the vector semileptonic branching ratio Γ(D0→K*(892)−μ+ν)Γ(D0→K¯0π−π+)=0.337±0.034±0.013.

Using data from the FOCUS experiment (FNAL-E831), we report on the decay of D 0 mesons into final states containing more than one K S 0 . We present evidence for two Cabibbo favored decay modes, D 0 → K S 0 K S 0 K − π + and D 0 → K S 0 K S 0 K + π − , and measure their combined branching fraction relative to D 0 → K ¯ 0 π + π − to be Γ ( D 0 → K S 0 K S 0 K ± π ∓ ) Γ ( D 0 → K ¯ 0 π + π − ) = 0.0106 ± 0.0019 ± 0.0010 . Further, we report new measurements of Γ ( D 0 → K S 0 K S 0 K S 0 ) Γ ( D 0 → K ¯ 0 π + π − ) = 0.0179 ± 0.0027 ± 0.0026 , Γ ( D 0 → K 0 K ¯ 0 ) Γ ( D 0 → K ¯ 0 π + π − ) = 0.0144 ± 0.0032 ± 0.0016 , and Γ ( D 0 → K S 0 K S 0 π + π − ) Γ ( D 0 → K ¯ 0 π + π − ) = 0.0208 ± 0.0035 ± 0.0021 where the first error is statistical and the second is systematic.

We present a new measurement of the branching ratio of the Cabibbo suppressed decay D 0 → π − μ + ν relative to the Cabibbo favored decay D 0 → K − μ + ν and an improved measurement of the ratio | f + π ( 0 ) / f + K ( 0 ) | . Our results are 0.074 ± 0.008 ± 0.007 for the branching ratio and 0.85 ± 0.04 ± 0.04 ± 0.01 for the form factor ratio, respectively.

Using a large sample of D 0 → K − μ + ν and D 0 → π − μ + ν decays collected by the FOCUS photoproduction experiment at Fermilab, we present new measurements of the q 2 dependence for the f + ( q 2 ) form factor. These measured f + ( q 2 ) form factors are fit to common parameterizations such as the pole dominance form and compared to recent unquenched Lattice QCD calculations. We find m pole = 1.93 ± 0.05 ± 0.03 GeV / c 2 for D 0 → K − μ + ν and m pole = 1.91 −0.15 +0.30 ± 0.07 GeV / c 2 for D 0 → π − μ + ν and f − ( K ) ( 0 ) / f + ( K ) ( 0 ) = − 1.7 −1.4 +1.5 ± 0.3 .

Using a high statistics sample of photo-produced charm particles from the FOCUS experiment at Fermilab, we report on the measurement of the ratio of semileptonic rates Γ ( D + → K π μ + ν μ ) / Γ ( D + → K ¯ 0 μ + ν μ ) = 0.625 ± 0.045 ± 0.034 . Allowing for the Kπ S-wave interference measured in [J.M. Link, et al., FOCUS Collaboration, Phys. Lett. B 544 (2002) 89], we extract the vector to pseudoscalar ratio Γ ( D + → K ¯ * 0 μ + ν μ ) / Γ ( D + → K ¯ 0 μ + ν μ ) = 0.594 ± 0.043 ± 0.033 and the ratio Γ ( D + → K ¯ 0 μ + ν μ ) / Γ ( D + → K − π + π + ) = 1.019 ± 0.076 ± 0.065 . Our results show a lower ratio for Γ ( D → K * l ν ) / Γ ( D → K l ν ) than has been reported recently and indicate the current world average branching fractions for the decays D + → K ¯ 0 ( μ + , e + ) ν μ , e are low. Using the world average B ( D + → K − π + π + ) [K. Hagiwara, et al., Particle Data Group Collaboration, Phys. Rev. D 66 (2002) 010001, and 2003 partial update for edition 2004 ( http://pdg.lbl.gov )] we extract B ( D + → K ¯ 0 μ + ν ) = ( 9.27 ± 0.69 ± 0.59 ± 0.61 ) % .

Using a large sample of D + → K − π + μ + ν decays collected by the FOCUS photoproduction experiment at Fermilab, we present new measurements of two semileptonic form factor ratios: r v and r 2 . We find r v =1.504±0.057±0.039 and r 2 =0.875±0.049±0.064. Our form factor results include the effects of the s -wave interference discussed in Phys. Lett. B 535 (2002) 43.

Using a large sample of charm semileptonic decays collected by the FOCUS photoproduction experiment at Fermilab, we present new measurements of two semileptonic branching ratios. We obtain values of Γ(D + → K ∗0 μ + ν) Γ(D + →K − π + π + ) =0.602±0.010( stat )±0.021( sys ) and Γ(D s + →φμ + ν) Γ(D s + →φπ + ) =0.54±0.033( stat )±0.048( sys ) . Our D + → K ∗0 μ + ν result includes the effects of the s-wave interference discussed in Phys. Lett. B 535 (2002) 43.

Using a large sample of charm semileptonic decays collected by the FOCUS photoproduction experiment at Fermilab, we present evidence for a small, even spin K−π+ amplitude that interferes with the dominant K ∗0 component in the D+→K−π+μ+ν final state. Although this interference significantly distorts the D+→K−π+μ+ν decay angular distributions, the new amplitude creates only a very small distortion to the observed kaon pion mass distribution when integrated over the other kinematic variables describing the decay. Our data can be described by K ∗0 interference with either a constant amplitude or broad spin zero resonance.

In this Letter we present a measurement of the natural widths of Σ c 0 and Σ c ++ . Using data from the FOCUS experiment, we find Γ ( Σ c 0 )=1.55 +0.41 −0.37 ±0.38 MeV/ c 2 and Γ ( Σ c ++ )=2.05 +0.41 −0.38 ±0.38 MeV/ c 2 . The first errors are statistical, the second systematic. These results are obtained with a sample of 913 Σ c 0 →Λ c + π − decays and 1110 Σ c ++ →Λ c + π + decays. These results are compared with recent theoretical predictions.

In this paper, we describe a dedicated test to study possible long-term aging effects on Resistive Plate Chambers (RPCs). A double gap detector was operated under gamma irradiation for a period approximately equal to 10 years of LHC in the CMS-barrel region: an integrated dose of about and a total charge of about gap were accumulated on the chamber. The results show no relevant aging effect. Also the RPC sensitivity to gamma energies is measured.

Folksonomies - networks of users, resources, and tags allow users to easily retrieve, organize and browse web contents. However, their advantages are still limited according to the noisiness of user provided tags. To overcome this problem, we propose an approach for identifying related tags in folksonomies. The approach uses tag co-occurrence statistics and Laplacian score feature selection to create probability distribution for each tag. Consequently, related tags are determined according to the distance between their distributions. In this regards, we propose a distance metric based on Jensen-Shannon Divergence. The new metric named AJSD deals with the noise in the measurements due to statistical fluctuations in tag co-occurrences. We experimentally evaluated our approach using WordNet and compared it to a common tag relatedness approach based on the cosine similarity. The results show the effectiveness of our approach and its advantage over the adversary method.