Security Policy Consistency

With the advent of wide security platforms able to express simultaneously all the policies comprising an organization's global security policy, the problem of inconsistencies within security policies become harder and more relevant. We have defined a tool based on the CHR language which is able to detect several types of inconsistencies within and between security policies and other specifications, namely workflow specifications. Although the problem of security conflicts has been addressed by several authors, to our knowledge none has addressed the general problem of security inconsistencies, on its several definitions and target specifications.Comment: To appear in the first CL2000 workshop on Rule-Based Constraint Reasoning and Programmin

Public transport towards sustainability in midsized municiplaities

Publicado em "Recent Advances in Engineering Mechanics, Structures and Urban Planning" (ISBN : 978-1-61804-165-4) ; Mathematics and Computers in Science and Engineering Series, 8 (ISSN : 2227-4588)The concept of sustainable urban mobility is related with the movement of people and goods in urban areas. However, this perspective is restrictive when the purpose is to address the problem of sustainability to an urban system of transport, in a big city, or as in this work, in urban areas of small and midsized municipalities, particularly in relation to the evaluation of economic, social, environmental and governance dimensions of the sustainable mobility. The assessment of mobility in urban areas implies the characterization of such areas, particularly in terms of geographic and socio-economic perspectives in order to understand and justify some issues of the existing relation between land use and transports. The framework of the transport system is related with the size of the municipalities. In this work an evaluation model of sustainability is proposed - that can be applied to evaluate and compare the level of sustainability in different urban areas of a system of public transports by bus, which can be also applied toother modes of transport. The model consists of a previous selection of indicators that characterize all dimensions of sustainability, which are then used in a multicriteria analysis. The weight of the indicators is defined by different groups of stakeholders related with the public transport system, mainly those concerned with decision-making process to promote its use at a local level, with the intention of defining priorities for improvement of public transport

A new perspective on street classification towards sustainability

Roads located in urban areas should take the generic concept of streets that should be studied and analyzed based on their various domains of characterization. However, one difficulty of this process is the high heterogeneity of the features of the different urban environments. Usually, a functional road classification is based on a dichotomous relationship between the functions of mobility and accessibility, although it was not possible to represent all types of roads of a road network in this type of classification or road hierarchies. Since road classification is a fundamental tool of urban planning, this paper presents a new proposal for classification and hierarchy of streets, which takes into account the perspective of sustainable urban development. Thus, this proposal envisages the evaluation of the performance of streets, which allows identifying the key issues and defining a set of strategies for their resolution through an environmental, social and economical perspective

Experimental assessment of RRM techniques in 5 GHz dense WiFi networks using REMs

“© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.”The increasing acceptance of WiFi has created unprecedented levels of congestion in the unlicensed frequency bands, especially in densely populated areas. This results mainly because of the unmanaged interference and uncoordinated op- eration between WiFi access points. Radio Environment Maps (REM) have been suggested as a support for coordination strategies that optimize the overall WiFi network performance. In this context, the main objective of this experiment is to assess the benefit of a coordinated management of radio resources in dense WiFi networks at 5 GHz band, using REMs for indoor scenarios. It was shown that REMs can detect the presence of interfering links on the network or coverage holes, and a suitable coordination strategy can use this information to reconfigure Access Points (AP) channel assignment and re-establish the client connection, at a cost of diminishing the aggregate throughput of the network. The technique of AP hand-off was tested to balance the load from one AP to another. Using REMs, the Radio Resource Management (RRM) strategy could reconfigure the network to optimize the client distribution among available APs. Although the aggregate throughput is lower after load balancing, the RRM could increase the throughput of the overloaded AP.info:eu-repo/semantics/publishedVersio