695 research outputs found

    Some partial-unit-memory convolutional codes

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    The results of a study on a class of error correcting codes called partial unit memory (PUM) codes are presented. This class of codes, though not entirely new, has until now remained relatively unexplored. The possibility of using the well developed theory of block codes to construct a large family of promising PUM codes is shown. The performance of several specific PUM codes are compared with that of the Voyager standard (2, 1, 6) convolutional code. It was found that these codes can outperform the Voyager code with little or no increase in decoder complexity. This suggests that there may very well be PUM codes that can be used for deep space telemetry that offer both increased performance and decreased implementational complexity over current coding systems

    Constructions for finite-state codes

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    A class of codes called finite-state (FS) codes is defined and investigated. These codes, which generalize both block and convolutional codes, are defined by their encoders, which are finite-state machines with parallel inputs and outputs. A family of upper bounds on the free distance of a given FS code is derived from known upper bounds on the minimum distance of block codes. A general construction for FS codes is then given, based on the idea of partitioning a given linear block into cosets of one of its subcodes, and it is shown that in many cases the FS codes constructed in this way have a d sub free which is as large as possible. These codes are found without the need for lengthy computer searches, and have potential applications for future deep-space coding systems. The issue of catastropic error propagation (CEP) for FS codes is also investigated

    Impact Properties of Hemp Fibre Reinforced Cementitious Composites

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    The construction industry has seen an incredibly fast increase in utilizing natural fibres for making low-cost building materials to achieve sustainable construction. One of such applications is natural fibre-reinforced cementitious materials for either structural or non-structural purpose. Impact properties are engineering properties received increasing attentions from engineering community for structural materials. This research therefore studies impact resistance of hemp fibre reinforced cementitious composites at early ages. Hemp fibre with various lengths, 10 mm and 20 mm, are utilized to reinforce cementitious materials. Hemp fibre reinforced cementitious composite slabs were tested under repeating dropping mass till failure at the age of 7, 14 and 28 days. Cracking behaviour, impact resistance, absorbed impact energy and survived impact blows upon failure are qualitatively/quantitatively analysed. It has been found that 20 mm-long hemp fibre reinforcement leads to higher impact resistance, more absorbed impact energy and survived more impact blows upon failure. Cementitious composite slabs reinforced by 20 mm-long hemp fibres exhibit higher impact crack resistance ratio than those reinforced by 10 mm-long fibres. Longer fibres are more effective in inhibiting the growth of micro-cracks and blunting the propagation of micro-cracks before they join up to form macro cracks leading to ultimate failure

    Emulating opportunistic networks with KauNet Triggers

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    In opportunistic networks the availability of an end-to-end path is no longer required. Instead opportunistic networks may take advantage of temporary connectivity opportunities. Opportunistic networks present a demanding environment for network emulation as the traditional emulation setup, where application/transport endpoints only send and receive packets from the network following a black box approach, is no longer applicable. Opportunistic networking protocols and applications additionally need to react to the dynamics of the underlying network beyond what is conveyed through the exchange of packets. In order to support IP-level emulation evaluations of applications and protocols that react to lower layer events, we have proposed the use of emulation triggers. Emulation triggers can emulate arbitrary cross-layer feedback and can be synchronized with other emulation effects. After introducing the design and implementation of triggers in the KauNet emulator, we describe the integration of triggers with the DTN2 reference implementation and illustrate how the functionality can be used to emulate a classical DTN data-mule scenario

    Isolation and identification of pathogenic bacteria from ready-to -eat fast foods in Al-Quwayiyah, Kingdom of Saudi Arabia

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    Food-borne pathogens are becoming a globally formidable health problem and perceived as a major health concern in the Kingdom of Saudi Arabia (KSA). Contamination ensued through unclean raw food materials and particles, use of polluted water, unhygienic preparation processes and use of contaminated containers. Herein, the prevalence of food-borne pathogens in ready-to-eat (RTE) fast foods from fifteen different food eateries such as 7 restaurants, 6 cafeterias and 2 two college canteens in Al-Quwayiyah, Riyadh Region of Saudi Arabia was studied. Microbiological analysis of 155 fast food samples which included, Vegetable salad, Falafel, Kibtha and Shawarma. The isolates were detected using biochemical tests and API 20E and slide agglutination test were conducted for Salmonella spp. detection. Bacterial growth was found in all food samples tested. Moreover, the test also showed high levels of total aerobic count: vegetable salad 6.34+0.03, falafel 5.79 + 0.18, kibtha 5.06 +0.02 and shawarma 3.54 + 0.13. Organisms isolated include Salmonella spp. (15%), Escherichia coli (18%) and Staphylococcus aureus (7%). Salmonella is one of the most virulent pathogen implicated in food-borne disease outbreaks. There are numerous transmission routes for Salmonellosis, but the majority of the human infections are derived from consumption of contaminated poultry products. Consistently, Salmonella Enteritidis, Salmonella Typhimurium and Salmonella Heidelberg are the three most frequent serotypes recovered from humans each year. Serologically identified Salmonella serotypes from RTE fast food samples were Salmonella Typhimurium with 65%, the most predominant one compared to Salmonella Enteritidis that was 35%. The bacterial count of vegetable salad, falahfel, kibtha was statistically significant when compared with Shawarma (p < 0.05). This result indicated that most of the ready-to-eat food samples examined in the study did not meet any bacteriological quality standard as recommended by The New South Wales (NSW) Food Authority to be <5.0 log10 CFU g−1 and, therefore, it poses potential risks to consumers. Ready- to- eat fast foods must be cooked and served to the consumers with all hygienic measures.Keywords: foodborne pathogen, microbial quality, Ready- to- eat fast foods, Al-QuwayiyahAfr. J. Food Agric. Nutr. Dev. 2019; 19(3): 14739-1475

    Anti-Tumour Effect In Vitro of Lymphocytes and Macrophages from Mice Treated with Corynebacterium Parvum

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    Cells from the spleen, lymph node, peripheral blood and peritoneal exudate of mice treated with C. parvum were tested for their ability to inhibit tumour growth in vitro. The peritoneal exudate cells from C. parvum treated mice were extremely effective in inhibiting tumour growth whereas the spleen and peripheral blood cells were only moderately so. In contrast, the lymph node cells caused only a modest inhibition of tumour growth at a very high effector to target cell ratio. Spleen cells from normal mice also exerted a moderate anti-tumour effect

    On the existence of optimum cyclic burst- correcting codes

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    Genome-wide imputed differential expression enrichment analysis identifies trait-relevant tissues

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    The identification of pathogenically-relevant genes and tissues for complex traits can be a difficult task. We developed an approach named genome-wide imputed differential expression enrichment (GIDEE), to prioritise trait-relevant tissues by combining genome-wide association study (GWAS) summary statistic data with tissue-specific expression quantitative trait loci (eQTL) data from 49 GTEx tissues. Our GIDEE approach analyses robustly imputed gene expression and tests for enrichment of differentially expressed genes in each tissue. Two tests (mean squared z-score and empirical Brown’s method) utilise the full distribution of differential expression p-values across all genes, while two binomial tests assess the proportion of genes with tissue-wide significant differential expression. GIDEE was applied to nine training datasets with known trait-relevant tissues and ranked 49 GTEx tissues using the individual and combined enrichment tests. The best-performing enrichment test produced an average rank of 1.55 out of 49 for the known trait-relevant tissue across the nine training datasets—ranking the correct tissue first five times, second three times, and third once. Subsequent application of the GIDEE approach to 20 test datasets—whose pathogenic tissues or cell types are uncertain or unknown—provided important prioritisation of tissues relevant to the trait’s regulatory architecture. GIDEE prioritisation may thus help identify both pathogenic tissues and suitable proxy tissue/cell models (e.g., using enriched tissues/cells that are more easily accessible). The application of our GIDEE approach to GWAS datasets will facilitate follow-up in silico and in vitro research to determine the functional consequence(s) of their risk loci

    Household’s Perception and their Willingness to Pay for Pesticides-Free Fruits in Khyber Pakhtunkhwa (Kp) Province of Pakistan: A Double-Bounded Dichotomous Choice Contingent Valuation Study

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    This study investigated household’s willingness to pay (WTP) for pesticide-free locally produced fresh fruits in Khyber Pakhtunkhwa, Pakistan. A Contingent Valuation Survey Method (CVM), constructed with a double-bounded WTP elicitation format, was used to interview a randomly selected sample of 600 households. Survey data revealed that households were willing to pay on average rupees 26 more per kilogram of pesticides free fruits. Results from regression analysis showed that age of the household head and his awareness of pesticides use over fruits, household size and their total monthly income were significant determinants of their WTP. In addition, health concern and environment concern of pesticides use also influence the WTP. Findings from this study help in assessing the market potential for pesticides-free fruits in Pakistan
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