Context-aware Authorization in Highly Dynamic Environments

Highly dynamic computing environments, like ubiquitous and pervasive computing environments, require frequent adaptation of applications. Context is a key to adapt suiting user needs. On the other hand, standard access control trusts users once they have authenticated, despite the fact that they may reach unauthorized contexts. We analyse how taking into account dynamic information like context in the authorization subsystem can improve security, and how this new access control applies to interaction patterns, like messaging or eventing. We experiment and validate our approach using context as an authorization factor for eventing in Web service for device (like UPnP or DPWS), in smart home security

Canadian Television Broadcasters and National Audiovisual Production: the Attitude of the Private Sector

This article examines the financial contribution of private television companies to the development and production of authentic Canadian programmes. Until the beginning of the 1980s, all Canadian television stations were under an obligation to produce as well as broadcast the great majority of their programming. This constituted a distinctive feature of Canadian broadcasting when compared to what had always been the case in the United States, not to mention a fundamental aspect of Canadian broadcasting policy since 1958. (It is important to note, however, that for the past several years private US television stations have been obliged to use Independent producers so as to conform to FCC (Federal Communities Commission) directives aimed at blocking the total monopoly over programme production and sales by large networks). Needless to say, this approach gave rise to heated, and at times acrimonious. debates between supporters of state intervention fostering national unity and the expression of Canadian culture by way of an indigenous audiovisual sector and advocates of laisser-faire economic policies. Thus from 1952 until 1961, the structure of Canadian television was composed of an English language and French-language public service. In 1961, taking inspiration from Great Britain, the state licenced private stations, obligating them to respect the same regulations governing the public service. Beginning in 1968, distribution of television signals by cable underwent considerable growth, eventually becoming an important component of the Canadian broadcasting system. Finally, in 1982, the first pay television services appeared, to be followed six years later by several specialty channels

Effect of Tree Form on the Productivity of a Cut-to-Length Harvester in a Hardwood Dominated Stand

It is commonly accepted that tree form has an impact on the productivity of single-grip harvesters. However, it remains unclear, which elements of tree form are significant and to what degree they impact harvesting productivity. This is of particular importance in hardwood dominated stands, where hardwood trees often exhibit complex and variable stem and crown architecture that can complicate and prolong the processing phase. With the development of specialized harvesting heads, hardwoods, which were mostly subject to motor-manual operations, are now increasingly being cut and processed with fully mechanized harvesting systems. The goal of this pilot project was to determine the effect of tree form on the productivity of mechanized cut-to-length harvesting. A time and motion study of a single-grip harvester, operating in a hardwood dominated stand, suggests that the presence of a fork or a large branch on the main stem can reduce machine harvesting productivity by 15 to 20%

Chemical and enzymatical modifications of sugar derived from lignocellulose

Actually, biorefinery is increasingly considered as a promising alternative to petroleum chemistry, since it aims at not only the replacement of fossil energy but also the development of chemicals from biomass, with applications such as detergents, phytopharmaceutics, solvents, plastics, etc. The valorisation of carbohydrates from renewable raw materials is currently the subject of numerous researches. In this context, the synthesis of new surfactants derived from the sugars issued from the lignocellulose hydrolysis was undertaken by chemical or enzymatic routes. In this poster, the examples of glucose, cellobiose and uronic acids will be discussed. Whatever the way used, the reaction conditions (use of a catalyst, protection/deprotection steps, type of solvent, presence of co-solvent, reactant concentrations, etc) were optimized to yield a panel of carbohydrate derivatives (some examples of the structures obtained are given above). These differ by the nature of the alkyl chain (in length and in degree of saturation), the type of chemical bond (amide, ester, thioester, acetal), and the position of substitution. The impact of these differences on the techno-functional properties of these modified sugars will be evaluated.Programme d'Excellence TECHNOS

Prevalence and prediction of previously unknown MRSA carriage on admission to a geriatric hospital

Objectives: to determine the prevalence and characteristics of previously unknown methicillin-resistant Staphylococcus aureus (MRSA) carriers at admission. Design: two prospective case-control studies. Subjects: 1,621 elderly patients were screened for MRSA carriage within 24 hours after admission to a geriatric hospital in Geneva, Switzerland. Methods: risk factors associated with previously unknown MRSA carriage were determined in the derivation group, and the resulting risk score was evaluated in the validation cohort using logistic regression analysis. Results: prevalence of MRSA carriage at admission increased from 7.3% (53/724 patients) in 2001 to 8.7% (78/897 patients) in 2003, with a corresponding prevalence of unknown MRSA carriers of 4.6 and 5.8%, respectively. Three variables were independently associated with previously unknown MRSA carriage: recent antibiotic treatment (adjusted OR (aOR) 2.3; 95% CI 1.0-5.1), intra-hospital transfer (aOR 2.5; 95% CI 1.2-5.3), and hospitalization in the past 2 years (aOR 2.7; 95% CI 1.1-6.7). In the validation cohort, the probability of MRSA carriage increased across risk scores: 0 point, 4% prevalence (6/146); 1 point, 15% (21/136); and $2 points, 31% (21/68; P<0.001). The risk score showed good discrimination and calibration in both groups. Conclusions: our risk score, which used a simple additive point system to estimate the likelihood of unknown MRSA carriage, had good accuracy and generalised well in an independent sample of patients. Once validated in a clinical trial, our risk score may be used as a tool to optimise MRSA contro

Determinants of compliance with anti-vectorial protective measures among non-immune travellers during missions to tropical Africa

International audienceThe effectiveness of anti-vectorial malaria protective measures in travellers and expatriates is hampered by incorrect compliance. The objective of the present study was to identify the determinants of compliance with anti-vectorial protective measures (AVPMs) in this population that is particularly at risk because of their lack of immunity