Optimized resource allocation in wireless systems

University of Technology, Sydney. Faculty of Engineering and Information Technology.Modern wireless systems rely to a great extent on the judicious distribution of available resources (e.g. power, bandwidth) to meet an ever increasing demand of better quality-of-service (QoS). Scarcity of these resources with time, coupled with the tremendous growth in numbers of users, network throughput, and applications, have resulted in making the problem of optimal resource allocation extremely important especially in wireless networks. Generally, optimization problems posed in the resource allocation framework are nonconvex and thus render it difficult to find an optimal solution. Previous studies on this subject have reported only numerically cumbersome and non-tractable solutions. This dissertation attempts to exploit the hidden convexity of the resource allocation problems under some given performance criteria such as minimum mean square error (MMSE) or signal-to-interference-plus-noise ratio (SINR) and then successfully finds tractable optimization formulations. The first research problem deals with the optimal power allocation and sensor assignment in linear and nonlinear networks for static and dynamic target tracking. The proposed method casts power allocation as a semi-definite program (SDP) while sensor selection is solved via d.c. (difference of convex functions/sets) programming. The second problem considers optimal beam-forming and source power allocation in relay-assisted multiuser communication. This problem is further extended to include multiple-antenna systems to exploit spatial diversity in modern cellular communication by jointly optimizing source precoding and relay processing matrices. Supremacy of the proposed d.c. programming based iterative algorithm over existing methods is demonstrated via extensive simulations

Overfishing Trends and the Global Food Crisis

Fish are a vital source of nourishment, especially to people in the world's poorest nations. Widespread over?shing has led to a decline in catch globally; however, the links between over?shing and food security have not been well-understood. The authors of scientific article "Food security implications of globalmarine catch losses due to overfishing." assessed potential losses, globally and regionally, in ?sheries catch and revenue resulting from over?shing. They found a third to a half of commercial marine species had been over?shed during the past half-century, with billions in potential revenue lost. By placing country-level catch loss trends in the context of undernourishment levels in many of the world's poorest countries, the authors estimated that in 2000 the additional catch from sustainable ?shing could have helped 20 million people cover their food de?cit and avert undernourishment. This Pew Ocean Science Series report is a summary of the scientists' ?ndings

A study of food aid leakage in Bangladesh

The estimated average leakage in the Vulnerable Group Development (VGD) programme due to short ration and undercoverage is 8 percent of the total wheat allotment. These losses are low by international and Bangladesh standards, and are due, in part, to monitoring and evaluation throughout the system and women's empowerment at the union level to hold programme managers accountable." from Text

Group-based financial institutions for the rural poor in Bangladesh: an institutional- and household-level analysis

Table of Contents: Tables, Figures, Foreword, Acknowledgments, and Summary; 1. Introduction; 2. Determinants of the Placement and Outreach of Group-Based Financial Institutions:A County-Level Analysis; 3. Group-Based Financial Institutions:Structure, Conduct, and Performance; 4. Household Participation in Financial Markets; 5. Analysis of the Household-Level Impact of Group-Based Credit Institutions in Bangladesh; 6. Conclusions and Implications for Policy; Appendix A: Survey Modules, Sampling Frame, and Location of Survey Sites; Appendix B: Adult Equivalent Consumption Units Differentiated by Age and Gender; ReferencesRural poor, Financial institutions, Microenterprises, Household surveys,

A statistical model to assess (allele-specific) associations between gene expression and epigenetic features using sequencing data

Sequencing techniques have been widely used to assess gene expression (i.e., RNA-seq) or the presence of epigenetic features (e.g., DNase-seq to identify open chromatin regions). In contrast to traditional microarray platforms, sequencing data are typically summarized in the form of discrete counts, and they are able to delineate allele-specific signals, which are not available from microarrays. The presence of epigenetic features are often associated with gene expression, both of which have been shown to be affected by DNA polymorphisms. However, joint models with the flexibility to assess interactions between gene expression, epigenetic features and DNA polymorphisms are currently lacking. In this paper, we develop a statistical model to assess the associations between gene expression and epigenetic features using sequencing data, while explicitly modeling the effects of DNA polymorphisms in either an allele-specific or nonallele-specific manner. We show that in doing so we provide the flexibility to detect associations between gene expression and epigenetic features, as well as conditional associations given DNA polymorphisms. We evaluate the performance of our method using simulations and apply our method to study the association between gene expression and the presence of DNase I Hypersensitive sites (DHSs) in HapMap individuals. Our model can be generalized to exploring the relationships between DNA polymorphisms and any two types of sequencing experiments, a useful feature as the variety of sequencing experiments continue to expand

Source and Sink Strength of Carbon Dioxide, Methane and Distribution of Sulfate in Salt-marsh Soils at the Wadden Sea Coast of Northern Germany

A field study was conducted at Schleswig-Holstein of Kiel in Germany to evaluate the factors controlling carbon and sulfate dynamics along a toposequence of coastal salt marsh soils. The soil at the top end of the salt marsh was salic silty to clayic Typic Sulfaquent (Salzrohmarsh) and the bottom end was sandy to silty Haplic Sulfaquent  Ubergangsmischwatt). The mean (depth: 0-100 cm) values of pH andrH were 6.8-6.9; 6.8-7.0 and 17.3-8.1; 15-8.6 for the Typic Sulfaquent (TS) and Haplic Sulfaquent (HS) throughout the year, respectively. The net-emission of CO2 was negative (-14.0 g m-2 yr-1) for the HS but highly positive (857 g m-2 yr-1) for the TS throughout the year. The annual emissions of CH4 were almost 10fold higher in HS (0.3 g m-2 yr-1) than that of the TS (0.03 g m-2 yr-1). The concentrations of CH4 at different seasons showed almost inverse relationships with the concentrations of CO2, varied significantly (p.0.05) with the seasons and depth function, and showed no dependence to temperature. The SO4 contents were observed maximum in the TS than that of HS during all the seasons. There was no noticeable correlation (r=-0.09) between SO4 and CH4 concentrations. Moreover, even CH4 was determined at depths where the SO4concentration was about 1200 mg SO4 L-

Biological Monitoring of Blood Naphthalene Levels as a Marker of Occupational Exposure to PAHs among Auto-Mechanics and Spray Painters in Rawalpindi

<p>Abstract</p> <p>Background</p> <p>Routine exposure to chemical contaminants in workplace is a cause for concern over potential health risks to workers. In Pakistan, reports on occupational exposure and related health risks are almost non-existent, which reflects the scarce availability of survey data and criteria for determining whether an unsafe exposure has occurred. The current study was designed to evaluate blood naphthalene (NAPH) levels as an indicator of exposure to polycyclic aromatic hydrocarbons (PAHs) among automobile workshop mechanics (MCs) and car-spray painters (PNs). We further determined the relationship between blood NAPH levels and personal behavioural, job related parameters and various environmental factors that may further be associated with elevated risks of occupational exposures to PAHs.</p> <p>Methods</p> <p>Sixty blood samples (n = 20 for each group i.e. MC, PN and control group) were collected to compare their blood NAPH levels among exposed (MCs and PNs) and un-exposed (control) groups. Samples were analyzed using high pressure liquid chromatography (HPLC). Data regarding demographic aspects of the subjects and their socioeconomic features were collected using a questionnaire. Subjects were also asked to report environmental hygiene conditions of their occupational environment.</p> <p>Results</p> <p>We identified automobile work areas as potential sites for PAHs exposure, which was reflected by higher blood NAPH levels among MCs. Blood NAPH levels ranged from 53.7 to 1980.6 μgL^-1and 54.1 to 892.9 μgL^-1among MCs and PNs respectively. Comparison within each group showed that smoking enhanced exposure risks several fold and both active and passive smoking were among personal parameters that were significantly correlated with log-transformed blood NAPH levels. For exposed groups, work hours and work experience were job related parameters that showed strong associations with the increase in blood NAPH levels. Poor workplace hygiene and ventilation were recognized as most significant predictors related to differences among workplaces that may enhance the extent of exposure to chemical contaminants.</p> <p>Conclusions</p> <p>It appeared that chemical exposure at the workplace may be influenced by multiple environmental factors, but poor workplace hygiene and duration of exposure (long work hours) were the most important factors. Smoking and negligence of workers regarding self protection were among some of the important personal behaviours than can be addressed with better training. There is also a need to improve workplaces hygiene and to rationalize work hours to minimize health risks. Since smoking was an important confounding factor that supplemented most of the actual occupational exposure, a study based on non-smoker subjects is needed to separate out the effects of smoking and other confounding factors that may obscure measurements of actual extent of occupational exposure.</p