Interest-Based Access Control for Content Centric Networks (extended version)

Content-Centric Networking (CCN) is an emerging network architecture designed to overcome limitations of the current IP-based Internet. One of the fundamental tenets of CCN is that data, or content, is a named and addressable entity in the network. Consumers request content by issuing interest messages with the desired content name. These interests are forwarded by routers to producers, and the resulting content object is returned and optionally cached at each router along the path. In-network caching makes it difficult to enforce access control policies on sensitive content outside of the producer since routers only use interest information for forwarding decisions. To that end, we propose an Interest-Based Access Control (IBAC) scheme that enables access control enforcement using only information contained in interest messages, i.e., by making sensitive content names unpredictable to unauthorized parties. Our IBAC scheme supports both hash- and encryption-based name obfuscation. We address the problem of interest replay attacks by formulating a mutual trust framework between producers and consumers that enables routers to perform authorization checks when satisfying interests from their cache. We assess the computational, storage, and bandwidth overhead of each IBAC variant. Our design is flexible and allows producers to arbitrarily specify and enforce any type of access control on content, without having to deal with the problems of content encryption and key distribution. This is the first comprehensive design for CCN access control using only information contained in interest messages.Comment: 11 pages, 2 figure

Energy Distribution in disordered elastic Networks

Disordered networks are found in many natural and artificial materials, from gels or cytoskeletal structures to metallic foams or bones. Here, the energy distribution in this type of networks is modeled, taking into account the orientation of the struts. A correlation between the orientation and the energy per unit volume is found and described as a function of the connectivity in the network and the relative bending stiffness of the struts. If one or both parameters have relatively large values, the struts aligned in the loading direction present the highest values of energy. On the contrary, if these have relatively small values, the highest values of energy can be reached in the struts oriented transversally. This result allows explaining in a simple way remodeling processes in biological materials, for example, the remodeling of trabecular bone and the reorganization in the cytoskeleton. Additionally, the correlation between the orientation, the affinity, and the bending-stretching ratio in the network is discussed

Magnetic superlens-enhanced inductive coupling for wireless power transfer

We investigate numerically the use of a negative-permeability "perfect lens" for enhancing wireless power transfer between two current carrying coils. The negative permeability slab serves to focus the flux generated in the source coil to the receiver coil, thereby increasing the mutual inductive coupling between the coils. The numerical model is compared with an analytical theory that treats the coils as point dipoles separated by an infinite planar layer of magnetic material [Urzhumov et al., Phys. Rev. B, 19, 8312 (2011)]. In the limit of vanishingly small radius of the coils, and large width of the metamaterial slab, the numerical simulations are in excellent agreement with the analytical model. Both the idealized analytical and realistic numerical models predict similar trends with respect to metamaterial loss and anisotropy. Applying the numerical models, we further analyze the impact of finite coil size and finite width of the slab. We find that, even for these less idealized geometries, the presence of the magnetic slab greatly enhances the coupling between the two coils, including cases where significant loss is present in the slab. We therefore conclude that the integration of a metamaterial slab into a wireless power transfer system holds promise for increasing the overall system performance

A large-scale proteogenomics study of apicomplexan pathogens-Toxoplasma gondii and Neospora caninum

Proteomics data can supplement genome annotation efforts, for example being used to confirm gene models or correct gene annotation errors. Here, we present a large‐scale proteogenomics study of two important apicomplexan pathogens: Toxoplasma gondii and Neospora caninum. We queried proteomics data against a panel of official and alternate gene models generated directly from RNASeq data, using several newly generated and some previously published MS datasets for this meta‐analysis. We identified a total of 201 996 and 39 953 peptide‐spectrum matches for T. gondii and N. caninum, respectively, at a 1% peptide FDR threshold. This equated to the identification of 30 494 distinct peptide sequences and 2921 proteins (matches to official gene models) for T. gondii, and 8911 peptides/1273 proteins for N. caninum following stringent protein‐level thresholding. We have also identified 289 and 140 loci for T. gondii and N. caninum, respectively, which mapped to RNA‐Seq‐derived gene models used in our analysis and apparently absent from the official annotation (release 10 from EuPathDB) of these species. We present several examples in our study where the RNA‐Seq evidence can help in correction of the current gene model and can help in discovery of potential new genes

Stratégie d'amélioration du service de l'eau et impacts sur les performances de l'irrigation dans le périmètre de la Moulouya

International audienceL'aridité du climat, l'irrégularité des précipitations, ainsi que les sécheresses de plus en plus fréquentes font de l'irrigation un impératif technique incontournable dans la politique de développement agricole et rural au Maroc. Le périmètre irrigué de la Moulouya est un exemple de l'importance de l'irrigation en agriculture. Le système d'irrigation gravitaire y est dominant, l'irrigation par aspersion concerne 22 % des surfaces et l'irrigation localisée 3,5 %, l'arboriculture fruitière couvre plus du tiers des surfaces, la betterave à sucre 4 000 ha, et la céréaliculture 15 000 ha. En effet, disposant d'atouts importants, (superficie équipée en ” grande hydraulique ” de 65 000 ha, sols très favorables, savoir-faire capitalisé par les fermiers, la proximité du marché européen et un tissu agro-industriel prometteur), le périmètre de la Moulouya est confronté à des contraintes techniques qui menacent l'agriculture (réduction de plus de la moitié des capacités de stockage à cause de l'envasement des barrages, variabilité des apports d'eau, vétusté des infrastructures hydro-agricoles, usage mixte des canaux principaux, morcellement des terres). Pour atténuer ces contraintes, l'Office régional de mise en valeur agricole de la Moulouya (couvrant une zone de 550 000 ha) a mis en oeuvre un plan d'amélioration du service de l'eau qui comprend la réhabilitation des infrastructures, la promotion de mesures pour économiser l'eau et le développement du management participatif. Il représente le deuxième projet d'amélioration de la grande irrigation (PAGI 2) financé par la Banque mondiale et se poursuit au sein du projet de réhabilitation de la grande irrigation (PRGI) financé par la Banque europ éenne d'investissement. La mise en oeuvre de ces actions a induit l'amélioration des performances de l'irrigation, que reflètent plusieurs indicateurs : l'efficience, le taux de maintenance, la disponibilité opérationnelle des réseaux d'irrigation, des critères ayant trait à l'économie de l'eau et à l'implication des usagers dans la gestion de l'eau. Le maintien du niveau de performance, résultant de ces projets, dépend de l'harmonisation des efforts attendus de tous les intervenants locaux et nationaux, et plus particulièrement de la participation des agriculteurs au sein des associations et de leur contribution aux économies d'eau à la parcelle

Reference management software for systematic reviews and meta-analyses: an exploration of usage and usability

BACKGROUND: Reference management software programs enable researchers to more easily organize and manage large volumes of references typically identified during the production of systematic reviews. The purpose of this study was to determine the extent to which authors are using reference management software to produce systematic reviews; identify which programs are used most frequently and rate their ease of use; and assess the degree to which software usage is documented in published studies. METHODS: We reviewed the full text of systematic reviews published in core clinical journals indexed in ACP Journal Club from 2008 to November 2011 to determine the extent to which reference management software usage is reported in published reviews. We surveyed corresponding authors to verify and supplement information in published reports, and gather frequency and ease-of-use data on individual reference management programs. RESULTS: Of the 78 researchers who responded to our survey, 79.5% reported that they had used a reference management software package to prepare their review. Of these, 4.8% reported this usage in their published studies. EndNote, Reference Manager, and RefWorks were the programs of choice for more than 98% of authors who used this software. Comments with respect to ease-of-use issues focused on the integration of this software with other programs and computer interfaces, and the sharing of reference databases among researchers. CONCLUSIONS: Despite underreporting of use, reference management software is frequently adopted by authors of systematic reviews. The transparency, reproducibility and quality of systematic reviews may be enhanced through increased reporting of reference management software usage