118,068 research outputs found
Measuring the structural similarity among XML documents and DTDs
No full textIn applications involving spatio-temporal modelling, granularities of data may have to adapt according to the evolving semantics and significance of data. In this paper we define ST 2_ODMGe, a multigranular spatio-temporal model supporting evolutions, which encompass the dynamic adaptation of attribute granularities, and the deletion of attribute values. Evolutions are specified as Event - Condition - Action rules and are executed at run-time. The event, the condition, and the action may refer to a period of time and a geographical area. The evolution may also be constrained by the attribute values. The ability of dynamically evolving the object attributes results in a more flexible management of multigranular spatio-temporal data but it requires revisiting the notion of object consistency with respect to class definitions and access to multigranular object values. Both issues are formally investigated in the paper
Design and operation of a fail-operational 5kW 800V-12V DC-DC converter
No full textThe spreading of autonomous drive systems is causing the increase of electrical power request on the 12V vehicle power net because, more and more on-board actuators are realized with electrical drives. Moreover, a very important requirement for autonomous drive systems is the capability of each component to operate also after a failure. A fail operational DC/DC power converter is therefore necessary to achieve the 12V power-net derived from the main battery of electric vehicles. In this paper a fail operational DC-DC 800 V/12 V, 5 kW power converter for automotive application is proposed. The converter topology is designed to ensure operability after a single failure. In this work, the sizing design procedure of each component of the converter is presented. Moreover, a numerical model of the converter is built and used to test the power converter both in normal and faulty conditions. Numerical simulation results validate the proposed topology showing both good dynamic performances and the required fail operational capabilities
Extending the square root method to account for additive forecast noise in ensemble methods
No full textA square root approach is considered for the problem of accounting for model noise in the forecast step of the ensemble Kalman filter (EnKF) and related algorithms. The primary aim is to replace the method of simulated, pseudo-random additive so as to eliminate the associated sampling errors. The core method is based on the analysis step of ensemble square root filters, and consists in the deterministic computation of a transform matrix. The theoretical advantages regarding dynamical consistency are surveyed, applying equally well to the square root method in the analysis step. A fundamental problem due to the limited size of the ensemble subspace is discussed, and novel solutions that complement the core method are suggested and studied. Benchmarks from twin experiments with simple, low-order dynamics indicate improved performance over standard approaches such as additive, simulated noise, and multiplicative inflation
Privacy-preserving techniques for location-based services
No full textThis paper outlines solutions to the problem of location privacy in mobile distributed applications. It then summarizes a novel approach that takes into account personal privacy preferences by individuals. The approach is highly efficient and experiments have shown that can be deployed on small devices
Foreword for the special issue of selected papers from the 1st ACM SIGSPATIAL Workshop on Security and Privacy in GIS and LBS
No full textThe first Workshop on Security and Privacy in GIS and LBS (SPRINGL 2008) was organized on November 4, 2008 at Irvine (CA) in conjunction with the SIGSPATIAL International Conference on Advances in Geographic Information Systems (ACM GIS 2008). The goal of the SPRINGL workshop series is to provide a forum for researchers working in the area of geospatial data security and privacy. Both security and privacy are critical for geospatial applications because of the dramatic increase and dissemination of geospatial data in several application contexts including homeland security, environmental crises, and natural and industrial disasters. Furthermore, geospatial infrastructures are being leveraged by companies to provide a large variety of location-based services (LBS) able to tailor services to users. However, despite the increase of publicly accessible geospatial information only little attention is being paid to how to secure geospatial information systems (GIS) and LBS. Privacy is also of increasing concern given the sensitivity of personally-identifiable location information. This is despite major advancements that have been made in secure computing infrastructures and the secure and privacy-preserving management of traditional (relational) data in particular. The discussion at the workshop spanned across security and privacy aspects, as they relate to the management of geospatial data and to the development of emerging LBS. The present special issue of Transactions on Data Privacy contains four extended papers, focusing on privacy, that have been selected from the papers presented at SPRINGL 2008
Le restituzioni nelle convivenze non matrimoniali: una breve analisi casistica per qualche (divagante) considerazione di politica del diritto
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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