EFFICIENT DYNAMIC ADDRESSING BASED ROUTING FOR UNDERWATER WIRELESS SENSOR NETWORKS

This thesis presents a study about the problem of data gathering in the inhospitable underwater environment. Besides long propagation delays and high error probability, continuous node movement also makes it difficult to manage the routing information during the process of data forwarding. In order to overcome the problem of large propagation delays and unreliable link quality, many algorithms have been proposed and some of them provide good solutions for these issues, yet continuous node movements still need attention. Considering the node mobility as a challenging task, a distributed routing scheme called Hop-by-Hop Dynamic Addressing Based (H2- DAB) routing protocol is proposed where every node in the network will be assigned a routable address quickly and efficiently without any explicit configuration or any dimensional location information. According to our best knowledge, H2-DAB is first addressing based routing approach for underwater wireless sensor networks (UWSNs) and not only has it helped to choose the routing path faster but also efficiently enables a recovery procedure in case of smooth forwarding failure. The proposed scheme provides an option where nodes is able to communicate without any centralized infrastructure, and a mechanism furthermore is available where nodes can come and leave the network without having any serious effect on the rest of the network. Moreover, another serious issue in UWSNs is that acoustic links are subject to high transmission power with high channel impairments that result in higher error rates and temporary path losses, which accordingly restrict the efficiency of these networks. The limited resources have made it difficult to design a protocol which is capable of maximizing the reliability of these networks. For this purpose, a Two-Hop Acknowledgement (2H-ACK) reliability model where two copies of the same data packet are maintained in the network without extra burden on the available resources is proposed. Simulation results show that H2-DAB can easily manage during the quick routing changes where node movements are very frequent yet it requires little or no overhead to efficiently complete its tasks

EFFICIENT DYNAMIC ADDRESSING BASED ROUTING FOR UNDERWATER WIRELESS SENSOR NETWORKS

This thesis presents a study about the problem of data gathering in the inhospitable underwater environment. Besides long propagation delays and high error probability, continuous node movement also makes it difficult to manage the routing information during the process of data forwarding. In order to overcome the problem of large propagation delays and unreliable link quality, many algorithms have been proposed and some of them provide good solutions for these issues, yet continuous node movements still need attention. Considering the node mobility as a challenging task, a distributed routing scheme called Hop-by-Hop Dynamic Addressing Based (H2- DAB) routing protocol is proposed where every node in the network will be assigned a routable address quickly and efficiently without any explicit configuration or any dimensional location information. According to our best knowledge, H2-DAB is first addressing based routing approach for underwater wireless sensor networks (UWSNs) and not only has it helped to choose the routing path faster but also efficiently enables a recovery procedure in case of smooth forwarding failure. The proposed scheme provides an option where nodes is able to communicate without any centralized infrastructure, and a mechanism furthermore is available where nodes can come and leave the network without having any serious effect on the rest of the network. Moreover, another serious issue in UWSNs is that acoustic links are subject to high transmission power with high channel impairments that result in higher error rates and temporary path losses, which accordingly restrict the efficiency of these networks. The limited resources have made it difficult to design a protocol which is capable of maximizing the reliability of these networks. For this purpose, a Two-Hop Acknowledgement (2H-ACK) reliability model where two copies of the same data packet are maintained in the network without extra burden on the available resources is proposed. Simulation results show that H2-DAB can easily manage during the quick routing changes where node movements are very frequent yet it requires little or no overhead to efficiently complete its tasks

Macroeconomic Effects of Global Food and Oil Price Shocks to the Pakistan Economy: A Structural Vector Autoregressive (SVAR) Analysis.

This study examines the transmission channels through which the global food and oil price shocks affects selected macroeconomic variables including inflation rate, output, money balances, interest rate and real effective exchange rate for Pakistan using monthly data over the period 1990M1-2011M7. An empirical analysis is carried out by employing structural vector autoregressive (SVAR) framework. Generalised Impulse Response Functions and Generalised Forecast Variance Decompositions are employed to track the impact of oil and food price shocks to Pakistan‘s economy. Results suggest that oil price shock affects industrial production, appreciates real effective exchange rate negatively and affect inflation and interest rate positively. Whereas, following food price shocks, industrial output increases. Similarly, interest rate and inflation rate responds positively following food price shocks. However, the variation in interest rate due to food price shock is relatively larger than that of oil price shocks. Generalised impulse response functions reveal that real effective exchange rate is most important source of disturbances following either oil price or food price shocks. Generalised forecast variance decompositions analysis also supports the findings based on generalised impulse response functions. The result clearly reveals that oil and food price shocks significantly affect output, short-term interest rate, inflation rate and real effective exchange rate. However, among all, real effective exchange rate has seen a dominant source of variations in Pakistan. This implies that supply-side and demand-side disturbances originated by external shocks are the major sources of inflation (stagflation) in Pakistan. Keywords: Oil and Food Price Shocks, SVAR, GIRFs, GFEVDs, Pakista

Foreign Aid—Blessing or Curse: Evidence from Pakistan

The role of foreign aid in promoting economic growth is a debatable issue and remains unsettled at both theoretical and empirical levels. Pakistan has received a substantial amount of foreign aid since its Independence in 1947 but little improvement has been observed in its socio-economic development. This study considers the question as to whether foreign aid is a blessing or a curse for Pakistan. The empirical analysis is based on the ARDL cointegration approach. We examine the aid-growth link at the aggregate and disaggregate levels for the period 1972-2006. The results show negative and insignificant effects of foreign aid on the growth at the aggregate as well at the disaggregate level. The findings further suggest that domestic investment, export growth, and inflows of foreign direct investment are important contributors in enhancing economic growth in Pakistan. JEL classification: C13, C22, F23, F35, O11 Keywords: Foreign Aid, Economic Growth, FDI, Cointegratio

Modelling Trade, Investment, Growth and Liberalisation: Case Study of Pakistan

The role of trade in economic development as an engine of economic growth has been at the centre of hot policy debates over the past four decades. History supports the success of import liberalisation policy in the United States of America (USA) in the 1940s, Japan in 1960s and the exports promotion achievements of Asian Tigers in the 1970s and 1980s [Yen (2009)].1 There is no doubt that increased movement of goods and services across international borders over the past few decades has helped developing countries to achieve faster and sustainable growth. Many researchers argued that free trade has a key ingredient in facilitating transfer of technology from developed to developing countries [Heokman and Javorcik (2006) and Harding and Javorcik (2012)]. Theoretical literature suggest that trade liberalisation enhances economic growth and development through the specialisation and technological developments. The theoretical link between international trade and economic development can be traced back to the earlier writings of Classical Economists (Adam Smith and David Ricardo) and Neoclassical Economists (Heckscher and Ohlin) in the early part of nineteenth century. The Classical Economists hypothesised that nations gain from trade, and World production would grow when trading nations specialise according to the principles of comparative advantage. On the other hand, the Neo-classical Economists argued that countries will tend to specialise in those products that use abundant resources intensively in the production process. As a consequence, factors prices will tend to equalise across trading nations if production technologies remain identical throughout the world (Stolper-Samuelson approach)

Foreign Aid-Blessing or Curse: Evidence from Pakistan

The role of foreign aid in promoting economic growth is a debatable issue and remains unsettled at both theoretical and empirical levels. Pakistan has received a substantial amount of foreign aid since its Independence in 1947 but little improvement has been observed in its socio-economic development. This study considers the question as to whether foreign aid is a blessing or a curse for Pakistan. The empirical analysis is based on the ARDL cointegration approach. We examine the aid-growth link at the aggregate and disaggregate levels for the period 1972 2006. The results show negative and insignificant effects of foreign aid on the growth at the aggregate as well at the disaggregate level. The findings further suggest that domestic investment, export growth, and inflows of foreign direct investment are important contributors in enhancing economic growth in Pakistan.Foreign Aid, Economic Growth, FDI, Cointegration

Comparative study of biological activity of glutathione, sodium tungstate and glutathione-tungstate mixture

Glutathione (GSH) and sodium tungstate (Na2WO4) are important pharmacological agents. They provide protection to cells against cytotoxic agents and thus reduce their cytotoxicity. It was of interest to study the biological activity of these two pharmacological active agents. Different strains of bacteria were used and the zone of inhibition was determined for GSH, Na2WO4 and GSH+ Na2WO4 mixture. The results show high antibacterial activity of GSH as compared to Na2WO4 and Na2WO4+GSH mixture. It was observed that GSH antibacterial activity was significantly lowered upon addition of Na2WO4 to GSH aqueous solution. The results conclude with the proposed formation of W-SG complex in aqueous solution.Key words: Glutathione, sodium tungstate, antibacterial activity, strains of bacteria

Scalable heterogeneous nodes deployment algorithm for monitoring of underwater pipeline

Underwater Wireless Linear Sensor Networks (UW-LSNs) possess unique features as compared to the terrestrial sensor networks for pipeline monitoring. Other than long propagation delays for long range underwater pipelines and high error probability, homogeneous node deployment also makes it harder to detect and locate the pipeline leakage efficiently. Determining the exact leakage position with minimum delay stays a major issue where pipelines length is extremely long and expensive to deploy many underwater sensors. In order to tackle the problem of large scale pipeline monitoring and unreliable underwater link quality, many algorithms have been proposed and even some of them provided good solutions for these issues but the scalable nodes deployments still need focus and prime attention. In order to handle the problem of nodes deployment, we therefore propose a dynamic nodes deployment algorithm where every node in the network is assigned location in a quick and efficient way without needing any localization scheme. It provides an option to handle the heterogeneous types of nodes, distribute topology and mechanism in which new nodes are easily added to the network without affecting the existing network performance. The proposed distributed topology algorithm divides the pipeline length into segments and sub-segments in order to manage the higher delay issue. Normally nodes are randomly deployed for the long range underwater pipeline inspection yet it requires some proper dynamic nodes deployment algorithm assigning unique position to each nod

Etiology, clinical characteristics, and outcome of infective endocarditis: 10-year experience from a tertiary care center in Pakistan

This study was conducted to assess the clinical characteristics, causative agents, complications, and outcomes of infective endocarditis (IE) among patients presenting to our tertiary care center over the last decade. This retrospective cohort study included all adult patients admitted to the Aga Khan University Hospital with the diagnosis of IE over a ten-year period from 2010 to 2020. Outcomes variables included complications during hospitalization, surgical intervention, mortality, and length of stay. We identified a total of 305 cases out of which 176 (58%) were males and 129 (42%) were females. The mean age of the patients was 46.9±18.8 years. 95 (31%) had prosthetic valves in place. Staphylococcus aureus was isolated in 54 (39%) patients followed by coagulase-negative Staphylococcus in 23 (17%). Echocardiography revealed vegetations and abscesses in 236 (77%) and 4 (1%) patients, respectively. The most common valvular complication was mitral valve regurgitation found in 26 (9%) patients, followed by tricuspid valve regurgitation in 13 (4%) patients and aortic valve regurgitation in 11 (3%) patients. Furthermore, 81 (27%) patients suffered from heart failure and 66 (22%) from a stroke during hospitalization. The mean hospital length of stay was 10.4 ± 10.6 days. 64 (21%) patients required surgical repair and the overall mortality rate was 25%. Prosthetic valve endocarditis (OR = 3.74, 95% CI = 2.15-6.50,