When ignorance helps: Graphical multicast cost sharing games

In non-cooperative games played on highly decentralized networks the assumption that each player knows the strategy adopted by any other player may be too optimistic or even infeasible. In such situations, the set of players of which each player knows the chosen strategy can be modeled by means of a social knowledge graph in which nodes represent players and there is an edge from i to j if i knows j. Following the framework introduced in [7], we study the impact of social knowledge graphs on the fundamental multicast cost sharing game in which all the players want to receive the same communication from a given source in an undirected network. In the classical complete information case, such a game is known to be highly inefficient, since its price of anarchy can be as high as the total number of players ρ. We first show that, under our incomplete information setting, pure Nash equilibria always exist only if the social knowledge graph is directed acyclic (DAG). We then prove that the price of stability of any DAG is at least and provide a DAG lowering the classical price of anarchy to a value between and log²ρ. If specific instances of the game are concerned, that is if the social knowledge graph can be selected as a function of the instance, we show that the price of stability is at least , and that the same bound holds also for the price of anarchy of any social knowledge graph (not only DAGs). Moreover, we provide a nearly matching upper bound by proving that, for any fixed instance, there always exists a DAG yielding a price of anarchy less than 4. Our results open a new window on how the performances of non-cooperative systems may benefit from the lack of total knowledge among players.     

MIMOSA: context-aware adaptation for ubiquitous web access

The ubiquitous computing scenario is characterized by heterogeneity of devices used to access services, and by frequent changes in the user’s context. Hence, adaptation according to the user’s context and the used devices is necessary to allow mobile users to efficiently exploit Internet-based services. In this paper, we present a distributed framework, named MIMOSA, that couples a middleware for context-awareness with an intermediary-based architecture for content adaptation. MIMOSA provides an effective and efficient solution for the adaptation of Internet services on the basis of a comprehensive notion of context, by means of techniques for aggregating context data from distributed sources, deriving complex contextual situations from raw sensor data, evaluating adaptation policies, and solving possible conflicts. The middleware allows programmers to modularly build complex adaptive services starting from simple ones, and includes tools for assisting the user in declaring her preferences, as well as mechanisms for detecting incorrect system behaviors due to a wrong choice of adaptation policies. The effectiveness and efficiency of MIMOSA are shown through the development of a prototype adaptive service, and by extensive experimental evaluations.     

Design and Experimental Evaluation of an Adaptive Playout Delay Control Mechanism for Packetized Audio for Use over the Internet

We describe the design and the experimental evaluation of a playout delay control mechanism we have developed in order to support unicast, voice-based audio communications over the Internet. The proposed mechanism was designed to dynamically adjust the talkspurt playout delays to the traffic conditions of the underlying network without assuming either the existence of an external mechanism for maintaining an accurate clock synchronization between the sender and the receiver during the audio communication, or a specific distribution of the audio packet transmission delays. Performance figures derived from several experiments are reported that illustrate the adequacy of the proposed mechanism in dynamically adjusting the audio packet playout delay to the network traffic conditions while maintaining a small percentage of packet loss.     

Environmentally Friendly Photocatalytic Oxidation of Aromatic Alcohol to Aldehyde in Aqueous Suspension of Brookite TiO2

X-ray photoelectron spectroscopy (XPS) has been applied to the study pertaining to preparation and characterization of catalysts used in propylene polymerization. The analysis has indicated support/donor interaction in active support (adduct) and active support/TiCl₄ interaction during catalyst preparation process. A systematic study has been made to identify suitable adduct from a set of three adducts for catalyst synthesis. Precise binding energy of Titanium species on catalyst surface has been measured and its dispersion on support has been evaluated to correlate catalyst performance with the surface spectroscopic parameters.     

Untersuchung von isolierten Carbiden,Nitriden und Carbonitriden in niedriglegierten Stählen

Vergleich von vier Verfahren zum Lösen von unlegiertem Stahl mit geringen Gehalten an Vanadin, Niob, Titan und Aluminium. Verwendung von Versuchsstählen, die nur eine nichtmetallische Phase enthalten. Einfluß der Teilchengröße der ausgeschiedenen Phasen. Trennung und quantitative Bestimmung der extrahierten Phasen durch selektive Oxidation in wäßriger Lösung mit kontrolliertem Oxidationspotential.     

Effects of nuclear radiations on structure and molecular motions in some crystalline stereoregular polymers

Young's modulus and the mechanical damping factor have been determined between ?180 and +280°C. (at a frequency of several kilocycles), in samples of isotactic polypropylene, isotactic polystyrene, and trans-1,4-polybutadiene, subjected to pile irradiation (γ-rays and neutrons) at γ-doses from 90 to 4000 Mrad. In isotactic polypropylene no important structural changes are produced by the irradiation, except for a partial destruction of crystallinity. The samples receiving high radiation doses exhibit a low temperature loss region, which is attributed to the formation of a certain number of branches. Isotactic polystyrene shows very slight modifications of the dynamic mechanical properties at room temperature. At low temperature an increase of intensity of the δ relaxation phenomenon (probably due to oscillations of phenyl rings) with increasing radiation dose is observed. Important structural modifications produced by the radiation, destruction of crystallinity accompanied by crosslinking, which transform the material into a crosslinked rubber, are observed in trans-1,4-polybutadiene. Unlike conventional (sulfur) vulcanization, crosslinking by radiation does not cause a marked shift of the glass transition point. A secondary low-temperature relaxation effect, not existing in the unirradiated material, appears in the mechanical loss curves of the irradiated samples; it is attributed to the formation of ? CH₂? sequences in the main chains through saturation of C?C bonds. The mechanical spectrum of irradiated polybutadiene is very similar to those shown by crosslinked ethylene–butadiene copolymers.     

Catalysts for the aromatization ofn-butane prepared by surface-contact transfer of gallium onto ZSM-5 zeolite particles

ZSM-5 zeolite particles into which 0.6 weight per cent or less of gallium oxide has been incorporated by surface-contact transfer, may exhibit very high activity in the aromatization ofn-butane. In some cases, the yield in aromatics is as high as that obtained with the hybrid catalyst wherein the cocatalyst is prepared by evaporation of a solution of gallium nitrate in Ludox colloidal silica.     

A Peltier cell calorimeter for the direct measurement of the isothermal entropy change in magnetic materials

We developed a calorimetric technique to measure the isothermal magnetocaloric entropy change. The method consists in the use of Peltier cells as heat flow sensor and heat pump at the same time. In this paper, we describe the setup, the constitutive equations of the Peltier cell as sensor and actuator, and the calibration procedure. The Peltier heat is used to keep the sample isothermal when magnetic field is changed. The temperature difference between the sample and the thermal reservoir is kept by a digital control within 5 mK for a magnetic field rate of 20 mT s(-1). The heat flux sensitivity around 1 microW. With this method, it is possible to measure the magnetocaloric effect in magnetic materials by tracing the curves of the exchanged entropy Delta(e)s as a function of the magnetic field H. The method proves to be, in particular, suitable to reveal the role of the entropy production Delta(i)s, which is connected with hysteresis. Measurement examples are shown for Gd, BaFe(12)O(19) ferrite, and Gd-Si-Ge.     

PointCleanNet: Learning to Denoise and Remove Outliers from Dense Point Clouds

Point clouds obtained with 3D scanners or by image-based reconstruction techniques are often corrupted with significant amount of noise and outliers. Traditional methods for point cloud denoising largely rely on local surface fitting (e.g. jets or MLS surfaces), local or non-local averaging or on statistical assumptions about the underlying noise model. In contrast, we develop a simple data-driven method for removing outliers and reducing noise in unordered point clouds. We base our approach on a deep learning architecture adapted from PCPNet, which was recently proposed for estimating local 3D shape properties in point clouds. Our method first classifies and discards outlier samples, and then estimates correction vectors that project noisy points onto the original clean surfaces. The approach is efficient and robust to varying amounts of noise and outliers, while being able to handle large densely sampled point clouds. In our extensive evaluation, both on synthetic and real data, we show an increased robustness to strong noise levels compared to various state-of-the-art methods, enabling accurate surface reconstruction from extremely noisy real data obtained by range scans. Finally, the simplicity and universality of our approach makes it very easy to integrate in any existing geometry processing pipeline. Both the code and pre-trained networks can be found on the project page ( https://github.com/mrakotosaon/pointcleannet ).     

Predicting Intentions from Motion: The Subject-Adversarial Adaptation Approach

International Journal of Computer Vision - This paper aims at investigating the action prediction problem from a pure kinematic perspective. Specifically, we address the problem of recognizing...