Performance study of Hybrid Wireless Mesh Protocol(HWMP) for IEEE 802.11s WLAN Mesh Networks

Wireless Mesh Network (WMN) have been envisioned as an important solution to the next generation wireless networking which can be used in wireless community networks, wireless enterprise networks, transportation systems, home networking and last-mile wireless internet access. Many proprietary mesh solutions were developed by individual vendor but in order to interoperability; IEEE forms a task group called IEEE 802.11s to develop an integrated mesh networking solution. Hybrid Wireless Mesh protocol (HWMP) and airtime metrics as default routing protocol and routing metrics set by the task group. There is few test bed and many simulation studies have been done to evaluate the performance of the HWMP protocol with the assumption of unique type of flow with fixed packet size and packet rate. However, real networks carry a diverse application (video, voice, FTP, Email etc) with different characteristics (packet size, data rate). In this paper, we are investigated and analyzed the performance of HWMP protocol under such heterogeneous application characteristics

Estimation of Survival Rates of Female Breast Cancer Patients in Meerut City, India

There is no data available on cancer incidence pattern in Meerut City. This is the first report on breast cancer incidence in females among Meerut urban population during the period of 2008-09, which gives the first hand information on breast cancer incidence in females. The data for this report has been collected by us. The sources for cancer registration are the tertiary care government hospital and two private cancer referral centers in the region. A total of 285 breast cancer cases were registered during the period from 1st January, 2008 to 31st December, 2009. Complete data was analyzed by using SPSS Statistical Software version 17. Complete to Follow Up (CFU) patients survival rate were estimated by Actuarial Method (ACM) and Lost to Follow Up (LFU) patients survival rate were estimated by Lost Adjusted Survival Rate (LAR) Method.  The patients were followed up for more than three years. The overall survival rate in age group 40-49 (51%, OR=0.69, CI=0.35-01.32) was higher than that seen in other age groups were comparatively lower than other registries situated in India. Survival rate against Hindu patients (23%, OR=1.78, CI=0.93-3.27) was higher than Muslim patients and it was statistically significant. Patients with tumor size 2cm had a better survival rate (65%, OR=2.22, CI=1.22-3.98) and it was statistically significant (p=.008)

Carbon Capture and Storage

Emissions of carbon dioxide, the most important long-lived anthropogenic greenhouse gas, can be reduced by Carbon Capture and Storage (CCS). CCS involves the integration of four elements: CO 2 capture, compression of the CO2 from a gas to a liquid or a denser gas, transportation of pressurized CO 2 from the point of capture to the storage location, and isolation from the atmosphere by storage in deep underground rock formations. Considering full life-cycle emissions, CCS technology can reduce 65–85% of CO2 emissions from fossil fuel combustion from stationary sources, although greater reductions may be possible if low emission technologies are applied to activities beyond the plant boundary, such as fuel transportation. CCS is applicable to many stationary CO2 sources, including the power generation, refining, building materials, and the industrial sector. The recent emphasis on the use of CCS primarily to reduce emissions from coal-fired electricity production is too narrow a vision for CCS. Interest in CCS is growing rapidly around the world. Over the past decade there has been a remarkable increase in interest and investment in CCS. Whereas a decade ago, there was only one operating CCS project and little industry or government investment in R&D, and no financial incentives to promote CCS. In 2010, numerous projects of various sizes are active, including at least five large-scale full CCS projects. In 2015, it is expected that 15 large-scale, full-chain CCS projects will be running. Governments and industry have committed over USD 26 billion for R&D, scale-up and deployment. The technology for CCS is available today, but significant improvements are needed to support widespread deployment. Technology advances are needed primarily to reduce the cost of capture and increase confidence in storage security. Demonstration projects are needed to address issues of process integration between CO2 capture and product generation, for instance in power, cement and steel production, obtain cost and performance data, and for industry where capture is more mature to gain needed operational experience. Large-scale storage projects in saline aquifers are needed to address issues of site characterization and site selection, capacity assessment, risk management and monitoring. Successful experiences from five ongoing projects demonstrate that, at least on this limited scale, CCS can be safe and effective for reducing emissions. Five commercial-scale CCS projects are operational today with over 35 million tonnes of CO2 captured and stored since 1996. Observations from commercial storage projects, commercial enhanced oil recovery projects, engineered and natural analogues as well as theoretical considerations, models, and laboratory experiments suggest that appropriately selected and managed geological storage reservoirs are very likely to retain nearly all the injected CO2 for very long times, more than long enough to provide benefits for the intended purpose of CCS. Significant scale-up compared to existing CCS activities will be needed to achieve large reductions in CO2 emissions. A 5- to 10-fold scale-up in the size of individual projects is needed to capture and store emissions from a typical coal-fired power plant (500 to 1000 MW). A thousand fold scale-up in size of today’s CCS enterprise would be needed to reduce emissions by billions of tonnes per year (Gt/yr). The technical potential of CCS on a global level is promising, but on a regional level is differentiated. The primary technical limitation for CCS is storage capacity. Much more work needs to be done to realistically assess storage capacity on a worldwide, regional basis and sub-regional basis. Worldwide storage capacity estimation is improving but more experience is needed. Estimates for oil and gas reservoirs are about 1000 GtCO2, saline aquifers are estimated to have a capacity ranging from about 4000 to 23,000 GtCO2. However, there is still considerable debate about how much storage capacity actually exists, particularly in saline aquifers. Research, geological assessments and, most importantly, commercial-scale demonstration projects will be needed to improve confidence in capacity estimates. Costs and energy requirements for capture are high. Estimated costs for CCS vary widely, depending on the application (e.g. gas clean-up vs. electricity generation), the type of fuel, capture technology, and assumptions about the baseline technology. For example, with today’s technology, CCS would increase cost of generating electricity by 50–100%. In this case, capital costs and parasitic energy requirements of 15–30% are the major cost drivers. Research is underway to lower costs and energy requirements. Early demonstration projects are likely to cost more. The combination of high cost and low or absent incentives for large-scale deployment are a major factor limiting the widespread use of CCS. Due to high costs, CCS will not take place without strong incentives to limit CO2 emissions. Certainty about the policy and regulatory regimes will be crucial for obtaining access to capital to build these multi-billion dollar projects. Environmental risks of CCS appear manageable, but regulations are needed. Regulation needs to ensure due diligence over the lifecycle of the project, but should, most importantly, also govern site selection, operating guidelines, monitoring and closure of a storage facility. Experience so far has shown that local resistance to CO2 storage projects may appear and can lead to cancellation of planned CCS projects. Inhabitants of the areas around geological storage sites often have concerns about the safety and effectiveness of CCS. More CCS projects are needed to establish a convincing safety record. Early engagement of communities in project design and site selection as well as credible communication can help ease resistance. Environmental organisations sometimes see CCS as a distraction from a sustainable energy future. Social, economic, policy and political factors may limit deployment of CCS if not adequately addressed. Critical issues include ownership of underground pore space (primarily an issue in the US); long-term liability and stewardship; GHG accounting approaches and ve rification; and regulatory oversight regimes. Governments and the private sector are making significant progress on all of these issues. Government support to lower barriers for early deployments is needed to encourage private sector adoption. Developing countries will need support for technology access, lowering the cost of CCS, developing workforce capacity and training regulators for permitting, monitoring and oversight. CCS combined with biomass can lead to negative emissions . Such technologies are likely to be needed to achieve atmospheric stabilization of CO2 and may provide an additional incentive for CCS adoption

Population structure, biogeography and transmissibility of mycobacterium tuberculosis

Mycobacterium tuberculosis is a clonal pathogen proposed to have co-evolved with its human host for millennia, yet our understanding of its genomic diversity and biogeography remains incomplete. Here we use a combination of phylogenetics and dimensionality reduction to reevaluate the population structure of M. tuberculosis, providing an in-depth analysis of the ancient Indo-Oceanic Lineage 1 and the modern Central Asian Lineage 3, and expanding our understanding of Lineages 2 and 4. We assess sub-lineages using genomic sequences from 4939 pan-susceptible strains, and find 30 new genetically distinct clades that we validate in a dataset of 4645 independent isolates. We find a consistent geographically restricted or unrestricted pattern for 20 groups, including three groups of Lineage 1. The distribution of terminal branch lengths across the M. tuberculosis phylogeny supports the hypothesis of a higher transmissibility of Lineages 2 and 4, in comparison with Lineages 3 and 1, on a global scale. We define an expanded barcode of 95 single nucleotide substitutions that allows rapid identification of 69 M. tuberculosis sub-lineages and 26 additional internal groups. Our results paint a higher resolution picture of the M. tuberculosis phylogeny and biogeography.http://www.nature.com/naturecommunicationsam2022Medical Microbiolog

A primary interface selection policy in heterogeneous networks based on QoS

The number of wireless applications, services and devices such as mobile telephone handsets, laptops and personal digital assistant (PDAs) are growing rapidly. The next generation wireless technology systems are being devised with the vision of heterogeneity where a mobile user will be connected with multiple wireless networks like GPRS/UMTS, IEEE 802.1x, WiMAX and satellite etc. To connect the above devices, a primary interface can be assigned to a mobile node (MN). Mobile users should be connected with appropriate interfaces based on the application types and its requirements. Different types of services are provided by the Internet like file transfer, telephony, audio and video conferencing etc. Among these applications some are sensitive to delay, for example, audio and video conferencing and some are sensitive to quality like file sharing and remote login. This paper proposes a policy that determines different applications’ requirements and chooses an appropriate interface as a primary interface for respective application based on the networks condition to improve Quality-of-Service (QoS). Prior to forward a packet to the destination, the routers decide the routes for that data packet to an appropriate interface that have been selected by the routers. It also helps to select the primary address among all available addresses based on an algorithm and reduces network overloads

Enhanced handoff latency reduction mechanism in layer 2 and layer 3 of mobile IPv6 (MIPv6) network

Next Generation Networks (NGN) both static and mobile are expected to be fully Internet Protocol Version 6 (IPv6) based. Mobility in IPv6 (MIPv6) network was designed to provide Internet services to end users at anytime and anywhere. However, MIPv6 is not widely deployed yet due to handoff latency and other limitations leading to packet loss and Quality of Service (QoS) degradation for real time applications such as audio and video streaming. MIPv6 handoff latency can be categorized into layer 2 (L2) and layer 3 (L3) delays that includes link layer establishment delay, movement detection delay, address configuration delay and binding update or registration delay. Movement detection delay and address configuration including Duplicate Address Detection (DAD) in L2 and L3 respectively consume the highest time of the total delay. In order to reduce these handoff latencies, two solutions are proposed to focus all the delays both in L2 and L3. The first solution is the fuzzy logic technique based network awareness to reduce movement detection delay especially the scanning time in L2 in heterogeneous networks. The second solution is Parallel DAD (PDAD) to reduce address configuration time in L3. Both solutions benchmarked with OMNeT++ simulator show improvements over standard MIPv6 networks. The handoff latency reduced more than 50% and packet loss improved around 55% in L2. Moreover, in L3 the handoff latency reduction accounts for 70% and packet loss improved approximately 60%. The handoff latency is reduced from 1300 ms to 500 ms applying fuzzy logic technique at L2 and PDAD mechanism in L3 leading to overall delay reduction of 60%

Vertical handoff reduction mechanism using IEEE 802.21 standard in mobile IPv6 (MIPv6) network

Low handoff latency and minimum packet loss are envisioned important factors for the next generation Mobile IPv6 (MIPv6) based heterogeneous networks. To meet these constraints IEEE 802.21-Media Independent Handover (MIH) was introduced to enhance the Quality of Service (QoS) of the networks. The MIH provides link layer information to the network layer to reduce handoff latency while the mobile node (MN) changes its active interface to another interface. In this paper an additional entity “Smooth Handoff Controller” (SHC) and an algorithm are proposed to select alternative interfaces in advance while MN is using an active interface. This mechanism helps the MN to configure additional interfaces that reduces handoff latency and packet loss. The simulation result shows better performance over the standard MIPv6. The proposed mechanism is simulated using OMNeT++. The simulation results show 70% reduction of handoff latency and 40% to 45% reduction of packet loss thus indicating a large improvement towards achieving better QoS

Enhancement of handoff latency reduction mechanism of Mobile Internet Protocol Version 6 (MIPv6)

MIPv6 is envisioned for next generation networks to achieve ubiquitous and seamless communications for its wide address spaces and many additional features. However, MIPv6 is not widely deployed due to handoff latency and other limitations leading to packet loss and Quality of Service (QoS) degradation for real time applications such as audio and video streaming. MIPv6 handoff latency can be categorized into layer 2 (L2) and layer 3 (L3) delays that includes link layer establishment delay, movement detection delay, address configuration delay and binding update or registration delay. Movement detection delay and address configuration including Duplicate Address Detection (DAD) in layer 2 and layer 3 respectively consume the highest time of the total delay. Therefore, an optimal solution is needed to reduce the delays in both layers. In order to reduce these handoff latencies, two solutions are proposed to focus all the delays both in L2 and L3. The first solution is the fuzzy logic technique based network awareness to reduce movement detection delay especially the scanning time in layer 2 in heterogeneous networks. The second solution is parallel DAD (PDAD) to reduce address configuration time in layer 3. Both solutions benchmarked with OMNeT++ simulator show improvements over standard MIPv6 networks. The overall handoff reduced from 1300ms to 500ms applying fuzzy logic technique at L2 and PDAD mechanism in L3 that combines 60% improvements