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991.
Uichin Lee Biao Zhou Mario Gerla Eugenio Magistretti Paolo Bellavista Antonio Corradi 《Wireless Communications, IEEE》2006,13(5):52-57
Vehicular sensor networks are emerging as a new network paradigm of primary relevance, especially for proactively gathering monitoring information in urban environments. Vehicles typically have no strict constraints on processing power and storage capabilities. They can sense events (e.g., imaging from streets), process sensed data (e.g., recognizing license plates), and route messages to other vehicles (e.g., diffusing relevant notification to drivers or police agents). In this novel and challenging mobile environment, sensors can generate a sheer amount of data, and traditional sensor network approaches for data reporting become unfeasible. This article proposes MobEyes, an efficient lightweight support for proactive urban monitoring based on the primary idea of exploiting vehicle mobility to opportunistically diffuse summaries about sensed data. The reported experimental/analytic results show that MobEyes can harvest summaries and build a low-cost distributed index with reasonable completeness, good scalability, and limited overhead 相似文献
992.
We investigate, within the PAC learning model, the problem of learning nonoverlapping perceptron networks (also known as read-once formulas over a weighted threshold basis). These are loop-free neural nets in which each node has only one outgoing weight. We give a polynomial time algorithm that PAC learns any nonoverlapping perceptron network using examples and membership queries. The algorithm is able to identify both the architecture and the weight values necessary to represent the function to be learned. Our results shed some light on the effect of the overlap on the complexity of learning in neural networks. 相似文献
993.
994.
Mario Rapone Raffaela Calabria Gianpaolo Pulcini 《Quality and Reliability Engineering International》1989,5(1):47-52
Dependability has been recognized in the transportation reliability literature as an effective measure of transit system service quality. Dependability models link system dependability with reliability and maintainability characteristics of subsystems, incorporating special operating characteristics and recovery policy from failure of each particular transit system. In this paper a new transit system dependability model is proposed, which considers the possibility that a passenger may be delayed by the occurrence of more than one failure in a trip. The mathematical difficulties associated with the algebra of random variables are overcome by using the Monte Carlo method. The results of the proposed model are compared with those relative to different modelling approaches in the literature, by applying the model to a common test scenario. 相似文献
995.
A research project was carried out at the Swiss Federal Institute of Technology (ETH) to study the fire behaviour of hollow core timber slabs and timber‐concrete composite slabs. This paper describes the main results of the basic fire behaviour of timber measured in the study. The first part of the analysis looks at the charring rate of timber. In the second part a new calculation model for the temperature development in wood members exposed to the standard ISO‐fire is presented and compared with the fire test results. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
996.
Giovanni Ferraris Sergio De Rossi Delia Gazzoli Ida Pettiti Mario Valigi Giuliana Magnacca Claudio Morterra 《Applied Catalysis A: General》2003,240(1-2):119-128
The adsorption of CO at 77 K on zirconia-supported tungsten oxide (ZW) samples prepared by equilibrium adsorption or by impregnation and with tungsten content up to 12.4 W atoms nm−2 was studied with the aim of determining the coverage of ZrO2 surface by the supported tungsten oxospecies. As an essential background for quantitative volumetric measurements, ZW samples were investigated by FT-IR spectroscopy to identify the surface sites responsible for the CO adsorption. FT-IR showed that CO adsorbed selectively and irreversibly on Zrcus4+ centers of the support surface, but not on Wcus6+ sites. By volumetric determinations, the coverage of the zirconia surface by tungsten oxospecies was about 50% at maximum, irrespective of the preparation procedure and of the support crystallographic modification (monoclinic or tetragonal). Zirconia coverage remained significantly unchanged after leaching with a NH3 solution that removed tungsten oxospecies not directly interacting with the zirconia surface. This finding indicates that ZrO2 support coverage depends mainly on the tungsten species strongly anchored to the zirconia surface. 相似文献
997.
Introduces the Special Section "Ethnicity and psychoanalysis." The authors address how psychoanalytic formulations focus in the main on the study of the individual's internal structure, the study of the mind as a theater of conflict without much concern with the possible influence of ethnic components in psychic structure. Their interest is to extend the study of the mind as a theater of conflict to include the issue of ethnicity and ethnic tension. The authors further discuss providing a psychoanalytic perspective on ethnic tension, the ethnic unconscious, cultural background factors, and the psychological mechanism of ethnic tension in relation to the articles of the special section. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
998.
Mario Kozina Marin Golub Stjepan Groš 《International Journal of Information Security》2009,8(6):455-467
Web applications are ubiquitous in today’s businesses. The security of these applications is of utmost importance since security
breaches might negatively impact good reputation, and even result in bankruptcy. There are different methods of assessing
security of Web applications, mainly based on some automated method of scanning. One type of scan method feeds random data
to the application and monitors its behavior. The other type uses a database with predefined vulnerabilities that are checked
one by one until either a vulnerability is found, or it can be claimed that the application does not have any known vulnerabilities.
The important step in latter type of scan process is the identification of the application since in this case we are narrowing
number of checks and, as a consequence, the scan process is faster. This paper describes a method for Web application identification
based on a black box principle. Our method is based on the invariance of certain characteristics of Web applications. We experimentally
tested and confirmed the usefulness of this approach. 相似文献
999.
We present a method for animating deformable objects using a novel finite element discretization on convex polyhedra. Our finite element approach draws upon recently introduced 3D mean value coordinates to define smooth interpolants within the elements. The mathematical properties of our basis functions guarantee convergence. Our method is a natural extension to linear interpolants on tetrahedra: for tetrahedral elements, the methods are identical. For fast and robust computations, we use an elasticity model based on Cauchy strain and stiffness warping. This more flexible discretization is particularly useful for simulations that involve topological changes, such as cutting or fracture. Since splitting convex elements along a plane produces convex elements, remeshing or subdivision schemes used in simulations based on tetrahedra are not necessary, leading to less elements after such operations. We propose various operators for cutting the polyhedral discretization. Our method can handle arbitrary cut trajectories, and there is no limit on how often elements can be split. 相似文献
1000.
Due to the very wide bandwidth of UWB system, it is hard if not impossible to design high speed and high resolution ADCs with
today’s technology. This problem can be solved if the received UWB signal is split into a number of subbands by power splitters,
analog low-pass filters, mixers and digital filters. By doing this, each of subbands can be sampled at a fraction of effective
sampling frequency. In this paper, we present a simpler channelized receiver architecture for UWB systems than previously
published work. Moreover, we present a new, though more complex, channelized receiver design for UWB systems in a multipath
propagation environment. We also show through simulation that this new receiver achieves very good BER performance. 相似文献