2,889 research outputs found

    Density Controlled Divide-and-Rule Scheme for Energy Efficient Routing in Wireless Sensor Networks

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    Cluster based routing technique is most popular routing technique in Wireless Sensor Networks (WSNs). Due to varying need of WSN applications efficient energy utilization in routing protocols is still a potential area of research. In this research work we introduced a new energy efficient cluster based routing technique. In this technique we tried to overcome the problem of coverage hole and energy hole. In our technique we controlled these problems by introducing density controlled uniform distribution of nodes and fixing optimum number of Cluster Heads (CHs) in each round. Finally we verified our technique by experimental results of MATLAB simulations.Comment: 26th IEEE Canadian Conference on Electrical and Computer Engineering (CCECE2013), Regina, Saskatchewan, Canada, 201

    Cortisol Hormone Concentration and Meat Quality of Beef Cattle Stunned by Captive Bolt Stun Gun before Slaughtering

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    This study was aimed to describe cortisol hormone concentration and meat quality which were produced in beef cattle stunned with captive bolt stun gun before slaughtering. Blood and meat samples were taken from Brahman cross steers (n= 11) in two abattoirs located in West Java and Banten. Blood samples were collected immediately after slaughtering. Cortisol hormone concentration in the serum was measured by using radioimmunoassay (RIA). The descriptive, correlation, and regression analyses were used to interprete data. Meat quality assessment was based on pH, cooking loss, and complete drainage of blood. The average of cortisol hormone concentration was 26.59 ng/mL. Meat pH at 1 h postmortem and 24 h postmortem were 6.65 and 6.21, respectively. Meat cooking loss was 26.77%. Blood drainage in meat samples of each cattle showed complete drainage. There was a significant correlation (P<0.05) between cortisol concentrations and pH at 1 hour postmortem as well as cortisol concentration and cooking loss. There was no significant correlation between pH at 24 h postmortem and cooking loss. Cattle was stunned with a captive bolt stun gun before slaughtering produced meat with complete blood drainage but had high cortisol hormone concentration and pH ultimate. Key words: cortisol, quality of meat, stunning, captive bolt stun gu

    A Gapless, Unambiguous Genome Sequence of the Enterohemorrhagic Escherichia coli O157:H7 Strain EDL933.

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    Escherichia coli EDL933 is the prototypic strain for enterohemorrhagic E. coli serotype O157:H7, associated with deadly food-borne outbreaks. Because the publicly available sequence of the EDL933 genome has gaps and >6,000 ambiguous base calls, we here present an updated high-quality, unambiguous genome sequence with no assembly gaps

    Impact of dust cooling on direct collapse black hole formation

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    Observations of quasars at z>6 z > 6 suggest the presence of black holes with a few times 109 M\rm 10^9 ~M_{\odot}. Numerous models have been proposed to explain their existence including the direct collapse which provides massive seeds of 105 M\rm 10^5~M_{\odot}. The isothermal direct collapse requires a strong Lyman-Werner flux to quench H2\rm H_2 formation in massive primordial halos. In this study, we explore the impact of trace amounts of metals and dust enrichment. We perform three dimensional cosmological simulations for two halos of >107 M\rm > 10^7~M_{\odot} with Z/Z=104106\rm Z/Z_{\odot}= 10^{-4}-10^{-6} illuminated by an intense Lyman Werner flux of J21=105\rm J_{21}=10^5. Our results show that initially the collapse proceeds isothermally with T8000\rm T \sim 8000 K but dust cooling becomes effective at densities of 1081012 cm3\rm 10^{8}-10^{12} ~cm^{-3} and brings the gas temperature down to a few 100-1000 K for Z/Z106\rm Z/Z_{\odot} \geq 10^{-6}. No gravitationally bound clumps are found in Z/Z105\rm Z/Z_{\odot} \leq 10^{-5} cases by the end of our simulations in contrast to the case with Z/Z=104\rm Z/Z_{\odot} = 10^{-4}. Large inflow rates of 0.1 M/yr\rm \geq 0.1~M_{\odot}/yr are observed for Z/Z105\rm Z/Z_{\odot} \leq 10^{-5} similar to a zero-metallicity case while for Z/Z=104\rm Z/Z_{\odot} = 10^{-4} the inflow rate starts to decline earlier due to the dust cooling and fragmentation. For given large inflow rates a central star of 104 M\rm \sim 10^4~M_{\odot} may form for Z/Z105\rm Z/Z_{\odot} \leq 10^{-5}.Comment: Accepted for publication in ApJ, comments are still welcom

    Performance Analysis of Hierarchical Routing Protocols in Wireless Sensor Networks

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    This work focusses on analyzing the optimization strategies of routing protocols with respect to energy utilization of sensor nodes in Wireless Sensor Network (WSNs). Different routing mechanisms have been proposed to address energy optimization problem in sensor nodes. Clustering mechanism is one of the popular WSNs routing mechanisms. In this paper, we first address energy limitation constraints with respect to maximizing network life time using linear programming formulation technique. To check the efficiency of different clustering scheme against modeled constraints, we select four cluster based routing protocols; Low Energy Adaptive Clustering Hierarchy (LEACH), Threshold Sensitive Energy Efficient sensor Network (TEEN), Stable Election Protocol (SEP), and Distributed Energy Efficient Clustering (DEEC). To validate our mathematical framework, we perform analytical simulations in MATLAB by choosing number of alive nodes, number of dead nodes, number of packets and number of CHs, as performance metrics.Comment: NGWMN with 7th IEEE International Conference on Broadband and Wireless Computing, Communication and Applications (BWCCA 2012), Victoria, Canada, 201

    On Energy Efficiency and Delay Minimization in Reactive Protocols in Wireless Multi-hop Networks

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    In Wireless Multi-hop Networks (WMhNs), routing protocols with energy efficient and delay reduction techniques are needed to fulfill users demands. In this paper, we present Linear Programming models (LP_models) to assess and enhance reactive routing protocols. To practically examine constraints of respective LP_models over reactive protocols, we select AODV, DSR and DYMO. It is deduced from analytical simulations of LP_models in MATLAB that quick route repair reduces routing latency and optimizations of retransmission attempts results efficient energy utilization. To provide quick repair, we enhance AODV and DSR. To practically examine the efficiency of enhanced protocols in different scenarios of WMhNs, we conduct simulations using NS- 2. From simulation results, enhanced DSR and AODV achieve efficient output by optimizing routing latencies and routing load in terms of retransmission attempts

    HEER: Hybrid Energy Efficient Reactive Protocol for Wireless Sensor Networks

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    Wireless Sensor Networks (WSNs) consist of numerous sensors which send sensed data to base station. Energy conservation is an important issue for sensor nodes as they have limited power.Many routing protocols have been proposed earlier for energy efficiency of both homogeneous and heterogeneous environments. We can prolong our stability and network lifetime by reducing our energy consumption. In this research paper, we propose a protocol designed for the characteristics of a reactive homogeneous WSNs, HEER (Hybrid Energy Efficient Reactive) protocol. In HEER, Cluster Head(CH) selection is based on the ratio of residual energy of node and average energy of network. Moreover, to conserve more energy, we introduce Hard Threshold (HT) and Soft Threshold (ST). Finally, simulations show that our protocol has not only prolonged the network lifetime but also significantly increased stability period.Comment: 2nd IEEE Saudi International Electronics, Communications and Photonics Conference (SIECPC 13), 2013, Riyadh, Saudi Arabi
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