1,402 research outputs found

    Practical Provably Secure Multi-node Communication

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    We present a practical and provably-secure multimode communication scheme in the presence of a passive eavesdropper. The scheme is based on a random scheduling approach that hides the identity of the transmitter from the eavesdropper. This random scheduling leads to ambiguity at the eavesdropper with regard to the origin of the transmitted frame. We present the details of the technique and analyze it to quantify the secrecy-fairness-overhead trade-off. Implementation of the scheme over Crossbow Telosb motes, equipped with CC2420 radio chips, shows that the scheme can achieve significant secrecy gain with vanishing outage probability. In addition, it has significant overhead advantage over direct extensions to two-nodes schemes. The technique also has the advantage of allowing inactive nodes to leverage sleep mode to further save energy.Comment: Proceedings of the IEEE International Conference on Computing, Networking and Communications (ICNC 2014

    Parameter Identification of Systems with Noise in Input and Output

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    In the problem of system parameters identification, most treatments made previously have assumed that the input to the system was free from noise. However, there would be many instances, where it would be more practical to assume the input to be accompanied with additive noise. Such a case is considered in the present paper, and the asymptotic unbiased estimate is obtained under certain conditions. The extended matrix approach with the ordinary least square method is used for the estimation of the parameters of the systems and the noise filter. Order identification is also discussed for this system with input noise. An application of the obtained solution to a numerical example shows that it gives a satisfactory result, both in parameter identification and in order identification

    Optimization of deep learning features for age-invariant face recognition

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    This paper presents a methodology for Age-Invariant Face Recognition (AIFR), based on the optimization of deep learning features. The proposed method extracts deep learning features using transfer deep learning, extracted from the unprocessed face images. To optimize the extracted features, a Genetic Algorithm (GA) procedure is designed in order to select the most relevant features to the problem of identifying a person based on his/her facial images over different ages. For classification, K-Nearest Neighbor (KNN) classifiers with different distance metrics are investigated, i.e., Correlation, Euclidian, Cosine, and Manhattan distance metrics. Experimental results using a Manhattan distance KNN classifier achieves the best Rank-1 recognition rate of 86.2% and 96% on the standard FGNET and MORPH datasets, respectively. Compared to the state-of-the-art methods, our proposed method needs no preprocessing stages. In addition, the experiments show its privilege over other related methods

    Subclinical pulmonary pathogenic infection in camels slaughtered in Cairo, Egypt

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    Introduction: Camels migrate between the open boundaries of Sudan and Egypt either for grazing or for slaughtering. Bad hygiene and stress is often related to pulmonary diseases in camels. This study investigated whether camels slaughtered in Cairo carried pulmonary infections. Methodology: Five hundred lung tissues of slaughtered camels were examined and 100 samples suspected for pulmonary infection were subjected to microbial identification and histopathology. Results: A total of 70 lung tissues revealed 97 bacterial isolates of 8 species, including Staphylococcus aureus (37.14%), Escherichia coli (27.14%), Klebsiella pneumoniae (26.71%), Bacillus spp. (25.72%), Streptococcus pyogenes (10%), Corynebacterium spp. (8.85 %), Pasteurella spp. (2.85%), and Arcanobacterium pyogenes (1.4%). Some of these species were earlier reported to be associated with pulmonary infection. Histopathology revealed different types of pneumonia in 50% of the investigated lungs. Conclusions: A considerable number of apparently healthy camels carry pathogenic agents in their lower respiratory tracts. Immunosuppression and stressful conditions might influence these pathogens to induce respiratory diseases in camels. Thus, the infected camels might act as reservoir of these infections agents. If adequate care is not taken, this might be a threat to abattoir workers and may spread infections to humans

    A Longitudinal Study of Small Group Interaction in Social Virtual Reality

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    Now that high-end consumer phones can support immersive virtual reality, we ask whether social virtual reality is a promising medium for supporting distributed groups of users. We undertook an exploratory in-the-wild study using Samsung Gear VR headsets to see how existing social groups that had become geographically dispersed could use VR for collaborative activities. The study showed a strong propensity for users to feel present and engaged with group members. Users were able to bring group behaviors into the virtual world. To overcome some technical limitations, they had to create novel forms of interaction. Overall, the study found that users experience a range of emotional states in VR that are broadly similar to those that they would experience face-to-face in the same groups. The study highlights the transferability of existing social group dynamics in VR interactions but suggests that more work would need to be done on avatar representations to support some intimate conversations

    Discovery of a Histidine‐Based Scaffold as an Inhibitor of Gut Microbial Choline Trimethylamine‐Lyase

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    This is the peer reviewed version of the following article: Discovery of a Histidine‐Based Scaffold as an Inhibitor of Gut Microbial Choline Trimethylamine‐Lyase, which has been published in final form at https://doi.org/10.1002/cmdc.202000571. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.Anaerobic choline metabolism by human gut microbiota to produce trimethylamine (TMA) has recently evolved as a potential therapeutic target because of its association with chronic kidney disease and increased cardiovascular risks. Limited examples of choline analogues have been reported as inhibitors of bacterial enzyme choline TMA‐lyase (CutC), a key enzyme regulating choline anaerobic metabolism. We used a new workflow to discover CutC inhibitors based on focused screening of a diversified library of small molecules for intestinal metabolic stability followed by in vitro CutC inhibitory assay. This workflow identified a histidine‐based scaffold as a CutC inhibitor with an IC50 value of 1.9±0.2 μM. Remarkably, the identified CutC inhibitor was able to reduce the production of TMA in whole‐cell assays using various bacterial strains as well as in complex gut microbiota environment. The improved efficiency of the new scaffold identified in this study in comparison to previously reported CutC inhibitors would enable optimization of potential leads for in vivo screening and clinical translation. Finally, docking studies and molecular‐dynamic simulations were used to predict putative interactions created between inhibitor and CutC

    Genetic Algorithm Optimization Model for Determining the Probability of Failure on Demand of the Safety Instrumented System

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    A more accurate determination for the Probability of Failure on Demand (PFD) of the Safety Instrumented System (SIS) contributes to more SIS realiability, thereby ensuring more safety and lower cost. IEC 61508 and ISA TR.84.02 provide the PFD detemination formulas. However, these formulas suffer from an uncertaity issue due to the inclusion of uncertainty sources, which, including high redundant systems architectures, cannot be assessed, have perfect proof test assumption, and are neglegted in partial stroke testing (PST) of impact on the system PFD. On the other hand, determining the values of PFD variables to achieve the target risk reduction involves daunting efforts and consumes time. This paper proposes a new approach for system PFD determination and PFD variables optimization that contributes to reduce the uncertainty problem. A higher redundant system can be assessed by generalizing the PFD formula into KooN architecture without neglecting the diagnostic coverage factor (DC) and common cause failures (CCF). In order to simulate the proof test effectiveness, the Proof Test Coverage (PTC) factor has been incorporated into the formula. Additionally, the system PFD value has been improved by incorporating PST for the final control element into the formula. The new developed formula is modelled using the Genetic Algorithm (GA) artificial technique. The GA model saves time and effort to examine system PFD and estimate near optimal values for PFD variables. The proposed model has been applicated on SIS design for crude oil test separator using MATLAB. The comparison between the proposed model and PFD formulas provided by IEC 61508 and ISA TR.84.02 showed that the proposed GA model can assess any system structure and simulate industrial reality. Furthermore, the cost and associated implementation testing activities are reduced

    Polyisobutylene-paclitaxel conjugates with pendant carboxylic acids and polystyrene chains: Towards multifunctional stent coatings with slow drug release

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    Drug-eluting stents are used in the treatment of atherosclerosis, where the incorporation of anti-proliferative or anti-inflammatory drugs decreases the rate of restenosis, the recurrence of artery narrowing. However, these stents can suffer from limitations such as drug depletion and delamination of the drug-eluting coating from the stent surface. Described here is an approach aimed at addressing these issues. Starting from a maleic anhydride adduct of polyisobutylene (PIB) prepared from butyl rubber, ring opening using paclitaxel (PTX) or a combination of PTX and polystyrene (PS) afforded covalent conjugates of PTX and PIB or PIB-PS graft copolymers bearing pendant carboxylic acids. When coated on stainless steel, the drug release was slower than that from a control coating that ressembles a clinical formulation comprising a physical mixture of a PS-PIB-PS triblock copolymer (SIBS) and PTX. The PTX conjugates also exhibited enhanced adhesion to stainless steel and increased tensile strength in comparison with the starting rubber. Cytotoxicity assays indicated that the materials did not leach toxic levels of PTX into cell culture media. Nevertheless, they were capable of inhibiting the adhesion and proliferation of C2C12 cells on their surfaces. These properties are advantageous for the potential application of the materials as stent coatings

    Combined versus single locoregional therapy in the treatment of unresectable hepatocellular carcinoma

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    AbstractIntroductionSurgical and locoregional therapies are different options in HCC treatment, several locoregional techniques are used.PurposeThis study aimed to assess the effectiveness of transarterial chemoembolization (TACE), radiofrequency ablation (RFA) and combined therapy, in HCC management.Materials and methodsThe study was conducted at our University Hospital, from August 2011 to February 2013. It included 60 patients with HCC (40 males and 20 females, age ranged between 45 and 70years). Patients were classified into 3 groups, group 1 treated with TACE, group 2 with RFA, and group 3 with both techniques. Response was assessed by triphasic CT and alpha fetoprotein. Patients were classified into good and poor responders after one and six months and one year. Patients’ survival and incidence of recurrence were recorded.ResultsThe percentage of good responders was greater with combined therapy than with TACE and RFA (90%, 70%, and 60% respectively). The overall survival was 75% and the recurrence free survival was 60% in TACE, 90%, and 45% in RFA and 95% and 90% in combined therapy respectively.ConclusionCombined therapy is superior regarding good response, overall survival, and free recurrence survival than either TACE or RFA alone
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