IMPROVED VIRTUAL CIRCUIT ROUTING ALGORITHM FOR WIRELESS SENSOR NETWORKS UNDER THE ASPECT OF POWER AWARENESS

Routing algorithms have shown their importance in the power aware wireless micro-sensor networks. In this paper first we present virtual circuit algorithm (VCRA), a routing algorithm for wireless sensor networks. We analyze the power utilized by nodes to lengthen the battery life and thus improving the lifetime of wireless sensor network. We discuss VCRA in comparison with the Multihoprouter, an algorithm developed by UC Berkeley. Then we present Improved Virtual Circuit Routing Algorithm (IVCRA) which is an improved form of VCRA. In IVCRA node failure detection and path repairing scheme has been implemented. We also present the energy analysis of IVCRA and prove that IVCRA is the best choice. We first implement our routing algorithms in simulator TOSSIM and then on real hardware of mica2 mote-sensor network platform and prove the reliable routing of the data packets from different nodes to the base station. The motes used as nodes in our mote-sensor network are from Berkeley USA. By using simulator POWERTOSSIM, we estimate and present the energy utilized by different nodes of the network. At the end we present a comparison of our work with the network layer of Zigbee/IEEE 802.15.4, which is an emerging standard for wireless sensor networks and then compare its energy efficiency with the packet size chosen for our algorithm

Mortality of emergency abdominal surgery in high-, middle- and low-income countries

Background: Surgical mortality data are collected routinely in high-income countries, yet virtually no low- or middle-income countries have outcome surveillance in place. The aim was prospectively to collect worldwide mortality data following emergency abdominal surgery, comparing findings across countries with a low, middle or high Human Development Index (HDI). Methods: This was a prospective, multicentre, cohort study. Self-selected hospitals performing emergency surgery submitted prespecified data for consecutive patients from at least one 2-week interval during July to December 2014. Postoperative mortality was analysed by hierarchical multivariable logistic regression. Results: Data were obtained for 10 745 patients from 357 centres in 58 countries; 6538 were from high-, 2889 from middle- and 1318 from low-HDI settings. The overall mortality rate was 1⋅6 per cent at 24 h (high 1⋅1 per cent, middle 1⋅9 per cent, low 3⋅4 per cent; P < 0⋅001), increasing to 5⋅4 per cent by 30 days (high 4⋅5 per cent, middle 6⋅0 per cent, low 8⋅6 per cent; P < 0⋅001). Of the 578 patients who died, 404 (69⋅9 per cent) did so between 24 h and 30 days following surgery (high 74⋅2 per cent, middle 68⋅8 per cent, low 60⋅5 per cent). After adjustment, 30-day mortality remained higher in middle-income (odds ratio (OR) 2⋅78, 95 per cent c.i. 1⋅84 to 4⋅20) and low-income (OR 2⋅97, 1⋅84 to 4⋅81) countries. Surgical safety checklist use was less frequent in low- and middle-income countries, but when used was associated with reduced mortality at 30 days. Conclusion: Mortality is three times higher in low- compared with high-HDI countries even when adjusted for prognostic factors. Patient safety factors may have an important role. Registration number: NCT02179112 (http://www.clinicaltrials.gov)

A Novel Handover Algorithm for Mobile WiMAX

oai:ojs2.journals.pu.edu.pk:article/2For the end user mobility is one of the distinctive values that wireless technology offers. One of the main mobility challenges is to maintain an ongoing session without interruption, while on the move, even at vehicular speeds. This challenge is referred to as handoff, commonly known as Handover (HO). Performing HO well is critical to providing a good user experience. It is one of the key issues for every mobile network. Whether it's GSM Network, UMTS, or Mobile WiMAX, HO is equally important. This paper presents a new method to upgrade performance of HO. This novel mechanism of HO follows HO recommendations in the Institute of Electrical and Electronics Engineers (IEEE) 802.16e system i.e. cell reselection via scanning, HO decision, initiation and network entry including synchronization and ranging with a target Base Station (BS). This paper demonstrates performance metrics of HO via simulation and the steps involved in it from one BS to other BS for successful HO. This proposed HO algorithm takes latency as a key metric to evaluate, as it has direct impact on application performance perceived by a user. Simulation experiments have revealed that our approach has decreased HO latency for Network Entry Time while minimizing HO Process

An Efficient Channel Distribution in 5G Heterogeneous Cellular Networks For Eluding Cross-Tier Interference in Macro and Small Cells

In recent times it has been witnessed that the necessity of user data rate traffic has been increased for running high bandwidth real time video on demand applications. Therefore the way forward towards the future wireless networks technology is 5G Heterogeneous Cellular Networks. The 5G Heterogeneous Cellular Networks mainly comprises of two network hierarches. In first hierarchy there are Macro base stations with large macro cells which are serving macro users. In second hierarchy there are femto base stations referred as small cells which are serving femto users. The 5G Heterogeneous Cellular Networks encourages the use of large macro and small cells for better and efficient utilization and distribution of channel resources. In this study the Authors, have proposed an efficient RF channel distribution mechanism on the basis of FUE and MUE current SINR levels in 5G Heterogeneous Cellular Networks. On the basis of user present SINR levels the channels will be allocated by the Central MBS to MUEs and FUEs via FBS upon the user real time traffic demands. The major hurdle in RF channel allocation to FUEs and MUEs is cross tier interference at the downlink channel at the MUEs and FUEs from the transmitted signals of MBS and FBS. In this research an efficient RF channel allocation scheme is proposed on the basis of channel modeling constraints which will minimize the cross tier interference at the downlink channel at the MUEs and FUEs during RF channel allocation to FUEs and MUEs present in the same coverage area of Macro and small cell.  

An efficient radio frequency channel distribution in 5g heterogeneous cellular networks for avoiding cross-tier interference in macro and small cells

Recently, the need for user data rate traffic has increased for running high-bandwidth applications. Therefore, the way forward lies in 5G heterogeneous cellular networks. The 5G network is comprised of two network hierarchies. As the first hierarchy, there are MBSs with large macro cells for macro users. As the second hierarchy, there are FBSs referred to as small cells for femto users. The 5G networks encourage the use of large macro and small cells for efficient utilisation and distribution of channel resources. In this study, the authors have proposed an efficient RF channel distribution mechanism on the basis of the current SINR levels of FUEs and MUEs. On the basis of the users’ present SINR levels, the channels will be allocated by the central MBS to MUEs and FUEs via FBSs. The major obstacle in RF channel allocation to FUEs and MUEs is cross-tier interference at the downlink channel at the MUEs and FUEs from the transmitted signals of MBSs and FBSs. In this study, an efficient RF channel allocation scheme is proposed on the basis of channel modelling constraints, which will minimise the cross-tier interference at the downlink channel at the MUEs and FUEs during RF channel allocation to FUEs and MUEs present in the same coverage are

Prolonging the Network Life Time in WSN through Computational Intelligence

Abstract-In this paper, key constituents of computational intelligence (CI) are discussed and how different classes come under the paradigm of CI. The very need and importance of CI in the problem solving of different social fabrics of life is comprehensively elaborated in this article and is concluded that CI in turn depicts the nature&apos;s supremacy of being the ultimate intelligent optimizer for human made solutions. This concept has become more highlighted due to the discussion about the emergence of computational intelligence from electronics to communication, from signal processing to pattern recognition and from microprocessor design to stochastic system. Wireless Sensor Network is taken as a target domain to implement the computational intelligence for the optimization of different factors involved in energy aware routing. Comparative analysis of different classes in CI paradigm is done to find the most appropriate class for optimization of Clustering design and data aggregation techniques. This analytical survey article can prove as a guiding light for the future researcher to delve into more detail of CI and finding the optimal solution in different social fabric of life. It is concluded that this nature inspired paradigm has the key role for moving to the &quot;optimized solutions&quot; for almost every field of life

E-MCDA: Extended-Multilayer Cluster Designing Algorithm for Network Lifetime Improvement of Homogenous Wireless Sensor Networks

The proposed idea in this paper is the constructive ramification of cluster designing mechanism floated in recently published work, multilayer cluster designing algorithm (MCDA) to ameliorate the performance in network lifetime. Novel algorithms for time slot allocation, minimizing the cluster head completion candidates, and cluster member selection∖node affiliation to cluster head play underpinning roles to achieve the target. These incorporations in MCDA result in minimizing transmissions, suppressing unfavorable response of transmissions and near-equal size and equal load clusters. We have done extensive simulations in NS2 and evaluate the performance of E-MCDA in energy consumption at various aspects of energy, packets transmission, number of designed clusters, number of nodes per cluster, and unclustered nodes. It is found that the proposed mechanism optimistically outperforms the competition with MCD and EADUC