2,385 research outputs found

    License distribution protocols from optical media fingerprints

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    According to the Business Software Alliance about 35% of the global software market, worth $141 Billion, is counterfeit. Most of the counterfeit software is distributed in the form of a compact disc (CD) or a digital video disc (DVD) which is easily copied and sold in street corners all around the world but mostly in developing countries. Given the severity of the problem at hand, a comprehensive solution taking into account the manufacturing process, economical implications, ease of enforcement, and the owner’s rights needs to be developed. While this is an enormous undertaking requiring new schemes at all levels of implementation, in this work, we focus only on a small part of the problem, i.e., secure fingerprinting techniques for optical media. © 2010, Springer-Verlag Berlin Heidelberg

    Millimeter-wave Wireless LAN and its Extension toward 5G Heterogeneous Networks

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    Millimeter-wave (mmw) frequency bands, especially 60 GHz unlicensed band, are considered as a promising solution for gigabit short range wireless communication systems. IEEE standard 802.11ad, also known as WiGig, is standardized for the usage of the 60 GHz unlicensed band for wireless local area networks (WLANs). By using this mmw WLAN, multi-Gbps rate can be achieved to support bandwidth-intensive multimedia applications. Exhaustive search along with beamforming (BF) is usually used to overcome 60 GHz channel propagation loss and accomplish data transmissions in such mmw WLANs. Because of its short range transmission with a high susceptibility to path blocking, multiple number of mmw access points (APs) should be used to fully cover a typical target environment for future high capacity multi-Gbps WLANs. Therefore, coordination among mmw APs is highly needed to overcome packet collisions resulting from un-coordinated exhaustive search BF and to increase the total capacity of mmw WLANs. In this paper, we firstly give the current status of mmw WLANs with our developed WiGig AP prototype. Then, we highlight the great need for coordinated transmissions among mmw APs as a key enabler for future high capacity mmw WLANs. Two different types of coordinated mmw WLAN architecture are introduced. One is the distributed antenna type architecture to realize centralized coordination, while the other is an autonomous coordination with the assistance of legacy Wi-Fi signaling. Moreover, two heterogeneous network (HetNet) architectures are also introduced to efficiently extend the coordinated mmw WLANs to be used for future 5th Generation (5G) cellular networks.Comment: 18 pages, 24 figures, accepted, invited paper

    Geochemical constraints on the Hadean environment from mineral fingerprints of prokaryotes

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    The environmental conditions on the Earth before 4 billion years ago are highly uncertain, largely because of the lack of a substantial rock record from this period. During this time interval, known as the Hadean, the young planet transformed from an uninhabited world to the one capable of supporting, and inhabited by the first living cells. These cells formed in a fluid environment they could not at first control, with homeostatic mechanisms developing only later. It is therefore possible that present-day organisms retain some record of the primordial fluid in which the first cells formed. Here we present new data on the elemental compositions and mineral fingerprints of both Bacteria and Archaea, using these data to constrain the environment in which life formed. The cradle solution that produced this elemental signature was saturated in barite, sphene, chalcedony, apatite, and clay minerals. The presence of these minerals, as well as other chemical features, suggests that the cradle environment of life may have been a weathering fluid interacting with dry-land silicate rocks. The specific mineral assemblage provides evidence for a moderate Hadean climate with dry and wet seasons and a lower atmospheric abundance of CO2 than is present today.Fil: Novoselov, Alexey A.. Universidad de Concepción; ChileFil: Silva, Dailto. Universidade Estadual de Campinas; BrasilFil: Schneider, Jerusa. Universidade Estadual de Campinas; BrasilFil: Abrevaya, Ximena Celeste. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Chaffin, Michael S.. State University Of Colorado Boulder; Estados UnidosFil: Serrano, Paloma. Alfred Wegener Institute Helmholtz Centre For Polar And Marine Research,; AlemaniaFil: Navarro, Margareth Sugano. Universidade Estadual de Campinas; BrasilFil: Conti, Maria Josiane. André Tosello Institute; BrasilFil: Souza Filho, Carlos Roberto de. Universidade Estadual de Campinas; Brasi

    Diversity across Seasons of Culturable Pseudomonas from a Desiccation Lagoon in Cuatro Cienegas, Mexico.

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    Cuatro Cienegas basin (CCB) is a biodiversity reservoir within the Chihuahuan desert that includes several water systems subject to marked seasonality. While several studies have focused on biodiversity inventories, this is the first study that describes seasonal changes in diversity within the basin. We sampled Pseudomonas populations from a seasonally variable water system at four different sampling dates (August 2003, January 2004, January 2005, and August 2005). A total of 70 Pseudomonas isolates across seasons were obtained, genotyped by fingerprinting (BOX-PCR), and taxonomically characterized by 16S rDNA sequencing. We found 35 unique genotypes, and two numerically dominant lineages (16S rDNA sequences) that made up 64% of the sample: P. cuatrocienegasensis and P. otitidis. We did not recover genotypes across seasons, but lineages reoccurred across seasons; P. cuatrocienegasensis was isolated exclusively in winter, while P. otitidis was only recovered in summer. We statistically show that taxonomic identity of isolates is not independent of the sampling season, and that winter and summer populations are different. In addition to the genetic description of populations, we show exploratory measures of growth rates at different temperatures, suggesting physiological differences between populations. Altogether, the results indicate seasonal changes in diversity of free-living aquatic Pseudomonas populations from CCB

    Cryptographic Primitives from Physical Variables

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    In this dissertation we explore a new paradigm emerging from the subtleties of cryptographic implementations and relating to theoretical aspects of cryptography. This new paradigm, namely physical variables (PVs), simply describes properties of physical objects designed to be identical but are not due to manufacturing variability. In the first part of this dissertation, we focus our attention on scenarios which require the unique identification of physical objects and we show how Gaussian PVs can be used to fulfill such a requirement. Using this framework we present and analyze a new technique for fingerprinting compact discs (CDs) using the manufacturing variability found in the length of the CDs\u27 lands and pits. Although the variability measured is on the order of 20 nm, the technique does not require the use of microscopes or any advanced equipment. Instead, the electrical signal produced by the photo-detector inside the CD reader will be sufficient to measure the desired variability. We thoroughly investigate the new technique by analyzing data collected from 100 identical CDs and show how to extract a unique fingerprint for each CD. In the second part, we shift our attention to physically parameterized functions (PPFs). Although all the constructions we provide are centered around delay-based physically unclonable functions (PUFs), we stress that the use of the term PUF could be misleading as most circuits labeled with the term PUF are in reality clonable on the protocol level. We argue that using a term like PPFs to describe functions parameterized by a PV is a more accurate description. Herein, we thoroughly analyze delay-PUFs and use a mathematical framework to construct two authentication protocols labeled PUF-HB and HB+PUF. Both these protocols merge the known HB authentication family with delay-based PUFs. The new protocols enjoy the security reduction put forth by the HB portion of the protocol and at the same time maintain a level of hardware security provided by the use of PUFs. We present a proof of concept implementation for HB+PUF which takes advantage of the PUF circuit in order to produce the random bits typically needed for an HB-based authentication scheme. The overall circuit is shown to occupy a few thousand gates. Finally, we present a new authentication protocol that uses 2-level PUF circuits and enables a security reduction which, unlike the previous two protocols, stems naturally from the usage of PVs

    Fluorescence characterization of clinically-important bacteria

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    Healthcare-associated infections (HCAI/HAI) represent a substantial threat to patient health during hospitalization and incur billions of dollars additional cost for subsequent treatment. One promising method for the detection of bacterial contamination in a clinical setting before an HAI outbreak occurs is to exploit native fluorescence of cellular molecules for a hand-held, rapid-sweep surveillance instrument. Previous studies have shown fluorescence-based detection to be sensitive and effective for food-borne and environmental microorganisms, and even to be able to distinguish between cell types, but this powerful technique has not yet been deployed on the macroscale for the primary surveillance of contamination in healthcare facilities to prevent HAI. Here we report experimental data for the specification and design of such a fluorescence-based detection instrument. We have characterized the complete fluorescence response of eleven clinically-relevant bacteria by generating excitation-emission matrices (EEMs) over broad wavelength ranges. Furthermore, a number of surfaces and items of equipment commonly present on a ward, and potentially responsible for pathogen transfer, have been analyzed for potential issues of background fluorescence masking the signal from contaminant bacteria. These include bedside handrails, nurse call button, blood pressure cuff and ward computer keyboard, as well as disinfectant cleaning products and microfiber cloth. All examined bacterial strains exhibited a distinctive double-peak fluorescence feature associated with tryptophan with no other cellular fluorophore detected. Thus, this fluorescence survey found that an emission peak of 340nm, from an excitation source at 280nm, was the cellular fluorescence signal to target for detection of bacterial contamination. The majority of materials analysed offer a spectral window through which bacterial contamination could indeed be detected. A few instances were found of potential problems of background fluorescence masking that of bacteria, but in the case of the microfiber cleaning cloth, imaging techniques could morphologically distinguish between stray strands and bacterial contamination

    Carbon Dots for Forensic Applications: A Critical Review

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    Owing to their superior fluorescence performance, inexpensive synthesis and nontoxic nature, carbon dots (C-dots) are systematically explored in a variety of applications; in this review, we outline and critically discuss recent trends with respect to their potential exploitation in criminal investigation, forensic toxicology and anti-counterfeit interventions. Capitalising on their colour-tuneable behaviour (in the sense that they adopt different colours with respect to the incident radiation), C-dot-based compositions are ideal for the visual enhancement of latent fingerprints, affording improved contrast against multicoloured and patterned backgrounds. As highly sensitive and highly selective optical nanoprobes, C-dots show excellent analytical performance in detecting biological compounds, drugs, explosives, heavy metals and poisonous reactants. In addition, benefiting from their versatile structural and chemical composition, C-dots can be incorporated into ink and polymeric formulations capable of functioning as a new generation of cost-effective barcodes and security nanotags for object authentication and anti-counterfeit applications. Translating these encouraging research outcomes into real-life innovations with significant social and economic impact requires an open, multidisciplinary approach and a close synergy between materials scientists, biologists, forensic investigators and digital engineers

    Environmental Burkholderia cenocepacia Strain Enhances Fitness by Serial Passages during Long-Term Chronic Airways Infection in Mice

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    Burkholderia cenocepacia is an important opportunistic pathogen in cystic fibrosis (CF) patients, and has also been isolated from natural environments. In previous work, we explored the virulence and pathogenic potential of environmental B. cenocepacia strains and demonstrated that they do not differ from clinical strains in some pathogenic traits. Here, we investigated the ability of the environmental B. cenocepacia Mex1 strain, isolated from the maize rhizosphere, to persist and increase its virulence after serial passages in a mouse model of chronic infection. B. cenocepacia Mex1 strain, belonging to the recA lineage IIIA, was embedded in agar beads and challenged into the lung of C57Bl/6 mice. The mice were sacrificed after 28 days from infection and their lungs were tested for bacterial loads. Agar beads containing the pool of B. cenocepacia colonies from the four sequential passages were used to infect the mice. The environmental B. cenocepacia strain showed a low incidence of chronic infection after the first passage; after the second, third and fourth passages in mice, its ability to establish chronic infection increased significantly and progressively up to 100%. Colonial morphology analysis and genetic profiling of the Mex1-derived clones recovered after the fourth passage from infected mice revealed that they were indistinguishable from the challenged strain both at phenotypic and genetic level. By testing the virulence of single clones in the Galleria mellonella infection model, we found that two Mex1-derived clones significantly increased their pathogenicity compared to the parental Mex1 strain and behaved similarly to the clinical and epidemic B. cenocepacia LMG16656(T). Our findings suggest that serial passages of the environmental B. cenocepacia Mex1 strain in mice resulted in an increased ability to determine chronic lung infection and the appearance of clonal variants with increased virulence in non-vertebrate hosts

    Metabolic fingerprinting of <i>Lactobacillus paracasei</i>:the optimal quenching strategy

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    BACKGROUND: Quenching in cold buffered methanol at −40 °C has long been the preferred method for sub-second inactivation of cell metabolism during metabolic fingerprinting. However, methanol is known to cause intracellular metabolite leakage of microbial cells, making the distinction between intra- and extracellular metabolites in microbial systems challenging. In this paper, we tested three quenching protocols proposed for microbial cultures: fast filtration, cold buffered methanol and cold glycerol saline. RESULTS: Our results clearly showed that cold glycerol saline quenching resulted in the best recovery of intracellular metabolites in Lactobacillus paracasei subsp. paracasei (L. paracasei). Membrane integrity assayed by propidium iodide revealed that approximately 10 % of the L. paracasei cell membranes were damaged by contact with the cold buffered methanol solution, whilst cold glycerol saline quenching led to minimal cell damage. Due to the nature of the L. paracasei culture, fast filtration took several minutes, which is far from ideal for metabolites with high intracellular turnover rates. CONCLUSION: The implementation of a reliable, reproducible quenching method is essential within the metabolomics community. Cold glycerol saline prevented leakage of intracellular metabolites, and, thus, allowed more accurate determinations of intracellular metabolite levels
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