CERTILOC: Implementation of a spatial-temporal certification service compatible with several localization technologies

The Third International Conference on Availability, Reliability and Security: ARES 2008 (March 4-7, 2008, Barcelona, Spain)Recently researchers are being encouraged to address security and privacy requirements for location information. This work contributes to this area by presenting CERTILOC, a prototype of a spatialtemporal certification service that is interoperable with representative localization technologies (GSM Cell-ID and GPS). Our work is completed with a broad threat analysis on spatial-temporal certification services and an exposition of legal considerations that can be made if used in work scenarios.Publicad

Performance evaluation of two-fuzzy based cluster head selection systems for wireless sensor networks

Sensor networks supported by recent technological advances in low power wireless communications along with silicon integration of various functionalities are emerging as a critically important computer class that enable novel and low cost applications. There are many fundamental problems that sensor networks research will have to address in order to ensure a reasonable degree of cost and system quality. Cluster formation and cluster head selection are important problems in sensor network applications and can drastically affect the network’s communication energy dissipation. However, selecting of the cluster head is not easy in different environments which may have different characteristics. In this paper, in order to deal with this problem, we propose two fuzzy-based systems for cluster head selection in sensor networks. We call these systems: FCHS System1 and FCHS System2. We evaluate the proposed systems by simulations and have shown that FCHS System2 make a good selection of the cluster head compared with FCHS System1 and another previous system.Peer ReviewedPostprint (published version

High-rise in trouble? Learning from Europe

Purpose All over the world, millions of people live in buildings and neighbourhoods that follow the principles of Congrès International d’Architecture Moderne (CIAM) and Le Corbusier: high-rise “residential machines” in parks reminiscent of green seas. Some of these have become very successful living environments, but in Europe and the USA, several neighbourhoods featuring this architectural design dream have become a social nightmare. Residents who were able to moved to more desirable neighbourhoods. This led to a high level of vacancy and crime and fear of crime have flourished, resulting in a stigma that is often long-lasting and difficult to repair. The pupose of this study is to learn from these experiences. Design/methodology/approach In this paper, two high-rise neighbourhoods, built in a Corbusier-like fashion and situated on the outskirts of major cities, are put under the evaluation spotlight: Bijlmermeer: located in Amsterdam, The Netherlands, with an abundance of landscaping, shrubbery, green fields and one high-density neighbourhood; and Bellvitge: located in Barcelona, Cataluña, Spain, looking less like a park and more like a city with open-air parking on ground level, and many small shops, bars and restaurants. Findings Both neighbourhoods faced enormous problems from crime, incivilities, disorder and drug abuse. Fear of crime and feelings of insecurity were high. Both governments reacted by investing huge sums of money. In Bellvitge, the investment was mainly in public transport, the public domain and new approaches in policing while keeping the high-rise buildings intact. In Bijlmermeer, a large regeneration project supported the demolition of two-thirds of all apartments and the neighbourhood was rebuilt in a low-rise fashion. Research limitations/implications This paper outlines the history of both neighbourhoods and describes the solutions that were implemented. Important lessons can be learned regarding current high-rise neighbourhoods and about the learning capacity of urban designers and planners regarding urban management. Practical implications The paper suggests that urban planners, designers and managers are slow in learning from earlier mistakes. The hypothesis is that there is no clear method available to evaluate new urban planning designs by incorporating lessons from the success or failure of previous cases. This paper focuses on density, ownership and design to identify possible approaches to evaluate new high-rise estate plans. Originality/value The Western high-rise “wave” has faded away but nowadays has become a high-rise “tsunami” in Asia. Learning from European experience may be beneficial.Peer ReviewedPostprint (author's final draft

Implementation of CAVENET and its usage for performance evaluation of AODV, OLSR and DYMO protocols in vehicular networks

Vehicle Ad-hoc Network (VANET) is a kind of Mobile Ad-hoc Network (MANET) that establishes wireless connection between cars. In VANETs and MANETs, the topology of the network changes very often, therefore implementation of efficient routing protocols is very important problem. In MANETs, the Random Waypoint (RW) model is used as a simulation model for generating node mobility pattern. On the other hand, in VANETs, the mobility patterns of nodes is restricted along the roads, and is affected by the movement of neighbour nodes. In this paper, we present a simulation system for VANET called CAVENET (Cellular Automaton based VEhicular NETwork). In CAVENET, the mobility patterns of nodes are generated by an 1-dimensional cellular automata. We improved CAVENET and implemented some routing protocols. We investigated the performance of the implemented routing protocols by CAVENET. The simulation results have shown that DYMO protocol has better performance than AODV and OLSR protocols.Peer ReviewedPostprint (published version

Genetic algorithms for satellite scheduling problems

Recently there has been a growing interest in mission operations scheduling problem. The problem, in a variety of formulations, arises in management of satellite/space missions requiring efficient allocation of user requests to make possible the communication between operations teams and spacecraft systems. Not only large space agencies, such as ESA (European Space Agency) and NASA, but also smaller research institutions and universities can establish nowadays their satellite mission, and thus need intelligent systems to automate the allocation of ground station services to space missions. In this paper, we present some relevant formulations of the satellite scheduling viewed as a family of problems and identify various forms of optimization objectives. The main complexities, due highly constrained nature, windows accessibility and visibility, multi-objectives and conflicting objectives are examined. Then, we discuss the resolution of the problem through different heuristic methods. In particular, we focus on the version of ground station scheduling, for which we present computational results obtained with Genetic Algorithms using the STK simulation toolkit.Peer ReviewedPostprint (published version

No surviving evolved companions to the progenitor of supernova SN 1006

Type Ia supernovae are thought to occur as a white dwarf made of carbon and oxygen accretes sufficient mass to trigger a thermonuclear explosion$^{1}$. The accretion could occur slowly from an unevolved (main-sequence) or evolved (subgiant or giant) star$^{2,3}$, that being dubbed the single-degenerate channel, or rapidly as it breaks up a smaller orbiting white dwarf (the double- degenerate channel)$^{3,4}$. Obviously, a companion will survive the explosion only in the single-degenerate channel$^{5}$. Both channels might contribute to the production of type Ia supernovae$^{6,7}$ but their relative proportions still remain a fundamental puzzle in astronomy. Previous searches for remnant companions have revealed one possible case for SN 1572$^{8,9}$, though that has been criticized$^{10}$. More recently, observations have restricted surviving companions to be small, main-sequence stars$^{11,12,13}$, ruling out giant companions, though still allowing the single-degenerate channel. Here we report the result of a search for surviving companions to the progenitor of SN 1006$^{14}$. None of the stars within 4' of the apparent site of the explosion is associated with the supernova remnant, so we can firmly exclude all giant and subgiant companions to the progenitor. Combined with the previous results, less than 20 per cent of type Iae occur through the single degenerate channel.Comment: Published as a letter in Nature (2012 September 27

Multispectral imaging methods for the diagnosis of skin cancer lesions

En col·laboració amb la Universitat Autònoma de Barcelona (UAB) i la Universitat de Barcelona (UB).Skin cancer is the most prevalent form of cancer, and melanoma is one of the most threat disease of it. But it can be cured if it is detected early enough. Multispectral imaging is a potential method to differenciate melanoma from nevi as it provides spectral images with information of absorbance and reflectance. With this aim, spectral images along the visible and near infrared range (from 415nm to 995nm) of 165 lesions including nevi, melanomas and basal cell carcinomas were processed in this master thesis. After obtaining all data in terms of reflectance and absorbance and other related parameters for each pixel of the segmented lesions, a statistical analysis was carried out to quantify their spatial distribution all over each lesion. Algorithms such as Support vector machine (SVM) and Discriminant Analysis (DA) were used as a means of classifying the lesions. The results show that DA linear classifier provides a better diagnosis than the SVM. BCCs are easier to discriminate from nevi than melanomas

Cryptographic Energy Costs are Assumable in Ad Hoc Networks

Performance of symmetric and asymmetric cryptography algorithms in small devices is presented. Both temporal and energy costs are measured and compared with the basic functional costs of a device. We demonstrate that cryptographic power costs are not a limiting factor of the autonomy of a device and explain how processing delays can be conveniently managed to minimize their impact