Adaptive Differential Feedback in Time-Varying Multiuser MIMO Channels

In the context of a time-varying multiuser multiple-input-multiple-output (MIMO) system, we design recursive least squares based adaptive predictors and differential quantizers to minimize the sum mean squared error of the overall system. Using the fact that the scalar entries of the left singular matrix of a Gaussian MIMO channel becomes almost Gaussian distributed even for a small number of transmit antennas, we perform adaptive differential quantization of the relevant singular matrix entries. Compared to the algorithms in the existing differential feedback literature, our proposed quantizer provides three advantages: first, the controller parameters are flexible enough to adapt themselves to different vehicle speeds; second, the model is backward adaptive i.e., the base station and receiver can agree upon the predictor and variance estimator coefficients without explicit exchange of the parameters; third, it can accurately model the system even when the correlation between two successive channel samples becomes as low as 0.05. Our simulation results show that our proposed method can reduce the required feedback by several kilobits per second for vehicle speeds up to 20 km/h (channel tracker) and 10 km/h (singular vector tracker). The proposed system also outperforms a fixed quantizer, with same feedback overhead, in terms of bit error rate up to 30 km/h.Comment: IEEE 22nd International Conference on Personal, Indoor and Mobile Radio Communications (2011

Essays on Macroeconomic Analysis of Development

This dissertation includes three essays on empirical studies of macroeconomic analysis of development. The first and second chapter focus on defining different categories of households based on the type of wealth they hold, deriving their demographic characteristics and how they react to transitory income shocks. The economics literature splits households into poor hand-to-mouth (P-HtM), wealthy hand-to-mouth (W-HtM), and not hand-to-mouth (N-HtM). This breakdown is important to accurately capture how different categories of households react to income shocks. In Chapter 1, I argue that this classification is missing important features related to the behavior of indebted households. Thus, novel in the literature, I define a new category of households: the indebted poor hand-to-mouth (IP-HtM), those that hold no net liquid assets (cash, checking, savings accounts etc.) and are indebted in illiquid wealth (negative net value of illiquid wealth defined as a negative net mortgage value that is not offset by positive illiquid assets such as private retirement accounts). I identify the share of such households in the United States, their demographic characteristics, their portfolio composition, and the persistence of their status over their life cycle. In the literature, they assimilate into the P-HtM households that hold neither net liquid nor net illiquid assets. However, I show that the age profile of IP-HtM households by demographic characteristics demonstrates almost the same pattern as W-HtM households that do not hold liquid assets but own sizable amounts of illiquid wealth. In the second chapter, I perform a detailed analysis of how various items of consumption such as food, nonfood, durable, nondurable, social sector, healthcare, utilities and education expenditure respond to transitory income shocks. The IP-HtM exhibits the highest marginal propensity to consume among all categories of households, for most consumption items. This implies that the stimulatory government’s policies are the most effective for the IP-HtMs. This research can help governments design and execute their fiscal policies targeting the highest stimulatory effect during recessions. In the third chapter, I use a 2013 survey of rickshaw pullers in Dhaka, Bangladesh to identify the determinants of their households’ healthcare expenditure using a flexible Box-Cox model regression method. The results suggest that income, distance of residence from healthcare center/hospital, age of household head, and duration of illness episode are the main determinants of healthcare utilization. The income elasticity of about 0.55 signals the tendency for healthcare to behave like a normal and necessary good. Since healthcare is a necessity in the “basic needs” theory of economic development, the way healthcare expenditure in a resource-constrained community responds to changes in income level and other factors is particularly relevant to development policy. Working-class populations in developing countries have unmet healthcare needs, and effective policies and programs are needed to ensure that healthcare services are received in a timely manner

Investigating the utilization of healthcare services to manage respiratory tract infections (RTIs) among Qatari patients attended selected primary healthcare centers in Qatar

Background: Respiratory-Tract-Infections (RTIs) are a common cause for most of the GP consultations and antibiotic use at primary care. The study aims to investigate the pattern, distribution, and determinants of several healthcare services use (RTI-related GP visits, antibiotic use, other medication uses and tests and investigations) to manage RTIs among local Qatari patients presented at the selected Primary Health Care Centers (PHCCs) in Qatar. Methods: A retrospective cross-sectional study was conducted in the selected seven (7) Primary Health Care Centers in Qatar for which a complete primary healthcare services data is available on the CERNER system from July 2015 to December 2017. We analyzed electronic data on RTIs-related GP consultations, antibiotic use, other medication uses, and tests and investigations recorded by the PHCC. Trends were investigated by employing linear regression analysis, including months and seasonal dummies as independent-variables. The rates of services use (per 1000 total cause visits) were presented by age-categories, gender, and comorbidity-status. We also analyzed individual patient-level count data on RTI-related 4 selected healthcare services use. A separate negative binomial regression model was used to identify determinants of healthcare services use. Results: A total of 171,447 RTI visits made by 58,786 patients during July-2015 to December-2017. The Mean age ±SD of participants is 24.80±18.5 years, among them 38.79% falls to age group 5-19 and 33.53% belongs to 20-44. Of the total patients, 48.91% are male and the rest are female. Highest number of patients with a comorbidity of Diabetes (12.85%), followed by Hypertension (10.54%). We have found no difference in the month-to-month rates of RTI-related GP visits (per 1000 total visits) over the study period (non-significant decreasing trend). However, there was a significant decreasing trend in the monthly rates of antibiotics consumption and an increasing trend in the tests/investigations done but there was no clear increasing or decreasing trend in the monthly rates of other medications use. As expected, we found lower number of RTI related healthcare services use during the summer months. After the bi-variate analysis of individual patient-level data of selected 4 health care services across age-categories, gender and various comorbidity status, we found healthcare services varied significantly across age-categories (younger patients relatively used more healthcare services compared to older patients) and whether patients had one of the five comorbidities. We have also found that age and comorbidity status (whether patients had a comorbidity or not) were important predictors for determining individual patient-level healthcare services use. Conclusion: In this study, antibiotic consumption for RTIs significantly decreased, as did consultation rates but investigations use rate significantly increased. The large seasonal variation indicates additional likelihoods to decrease healthcare service use. After the bi-variate analysis of individual patient-level data of selected 4 healthcare services across age-categories, gender and various comorbidity status, healthcare services varied significantly across age-categories and whether patients had one of the five comorbidities. We have also found that age and comorbidity status (whether patients had a comorbidity or not) were important predictors for determining individual patient-level healthcare services use. So, the first ever study investigating the utilization of healthcare services use by RTI patients presented at the 7 PHCC healthcare centers in Qatar, which may help policymakers to comprehend the scale of the utilization and to plan a better management of RTIs at primary care setting in Qatar.خلفية: عدوى الجهاز التنفسي تعد سببا شائعا لمعظم استشارات أطباء العموم ولاستخدام المضادات الحيوية في الرعاية الصحية الأولية. تستهدف هذه الدراسة استقصاء نمط وتوزيع ومحددات الاستخدام لخدمات الرعاية الصحية المتنوعة )زيارات أطباء العموم ذات الصلة بعدوى الجهاز التنفسي، استخدام المضادات الحيوية، استخدامات الأدوية الأخرى، والاختبارات والفحوص( لمعالجة عدوى الجهاز التنفسي لدى المرضى القطريين المحليين في مراكز الرعاية الصحية الأولية (PHCCs) المختارة بقطر. طرق البحث: تم إجراء دراسة مقطعية مرجعية في سبعة مراكز للرعاية الصحية الأولية في قطر لديها بيانات مكتملة عن خدمات الرعاية الصحية الأولية متوفرة على نظام السجلات الطبية الإلكترونية ) سيرنر( من يوليو 2015 إلى ديسمبر 2017 . قمنا بتحليل البيانات الإلكترونية عن استشارات الأطباء المتعلقة بعدوى الجهاز التنفسي، واستخدام المضادات الحيوية واستخدامات الأدوية الأخرى، والاختبارات والفحوص المسجلة من قبل مراكز الرعاية الصحية الأولية. تم اختبار الاتجاهات باستخدام تحليل الانحدار الخطي باعتبار المتغيرات الشكلية للشهور والمواسم كمتغيرات مستقلة. تم عرض معدلات استخدام الخدمات )لكل ألف من إجمالي أسباب الزيارات( من خلال الفئات العمرية، الجنس، والحالة المرضية. قمنا أيضا بتحليل بيانات عددية فردية على مستوى المريض عن استخدام أربع خدمات رعاية مختارة متعلقة بعدوى الجهاز التنفسي. استخدم نموذج انحدار ثنائي سلبي منفصل لتحديد محددات استخدام خدمات الرعاية الصحية. النتائج: إجمالا هناك 171447 زيارة بسبب الإصابة بعدوى الجهاز التنفسي قام بها 58786 مريضا خلال يوليو 2015 إلى ديسمبر 2017 . متوسط العمر ± الانحراف المعياري للمشاركين هو 24.80 ± 18.5 سنة، من بينهم 38.79 %ينتمون للفئة العمرية 5 - 19 عاما و 33.53 % ينتمون إلى الفئة العمرية 20 - 44 عاما. 48.91 % من إجمالي المرضى ذكور والباقي إناث. أعلى عدد من المرضى كانوا من الذين لديهم السكري كمرض مصاحب ) 12.85 ،)% يليه ارتفاع ضغط الدم ) 10.54 %(. لم نجد فرقا في المعدلات الشهرية لزيارات أطباء العموم المتعلقة بعدوى الجهاز التنفسي )لكل ألف زيارة إجمالية( على مدار فترة الدراسة )اتجاه تناقصي غير مهم إحصائيا(. غير أنه كان هناك اتجاه تناقصي ملحوظ في المعدلات الشهرية لاستهلاك المضادات الحيوية واتجاه تزايدي في الاختبارات / الفحوص التي أجريت، لكن لم يكن هناك اتجاه تزايدي أو تناقصي واضح في المعدلات الشهرية لاستخدام الأدوية الأخرى. وكما هو متوقع، وجدنا استخداما أقل للموارد ذات الصلة بعدوى الجهاز التنفسي أثناء أشهر الصيف. بعد التحليل ثنائي المتغير للبيانات الفردية على مستوى المريض عن أربع خدمات رعاية صحية مختارة عبر الفئات العمرية والجنس وحالة الأمراض المصاحبة، وجدنا أن خدمات الرعاية الصحية تختلف بشكل ملحوظ في الفئات العمرية )استخدم المرضى الأصغر سنا خدمات صحية أكثر نسبيا مقارنة بالمرضى كبار السن( وتختلف فيما إذا كان المرضى يشكون من واحد من الأمراض المصاحبة الخمسة. وجدنا أيضا أن العمر وحالة الأمراض المصاحبة )إذا كان المرضى لديهم مرض مصاحب أم لا( كانت منبئات مهمة لتحديد استخدام خدمات الرعاية الصحية الفردية على مستوى المريض. الاستنتاج: في هذه الدراسة، انخفض استهلاك المضادات الحيوية لعدوى الجهاز التنفسي بشكل ملحوظ إحصائيا، وبالمثل معدلات الاستشارات لكن معدل استخدام الفحوص ازداد بشكل ملحوظ. ويدل التغير الموسمي الكبير على وجود احتمالات إضافية لتقليل استخدام موارد الرعاية الصحية. بعد إجراء التحليل ثنائي المتغير للبيانات الفردية على مستوى المريض عن أربع خدمات رعاية صحية مختارة عبر الفئات العمرية والجنس وحالة الأمراض المصاحبة المختلفة، تفاوتت خدمات الرعاية الصحية بصورة ملحوظة في الفئات العمرية وفيما إذا كان المرضى لديهم واحدا من الأمراض المصاحبة الخمسة. وجدنا كذلك أن العمر وحالة المرض المصاحب )فيما إذا كان المرضى لديهم أمراض مصاحبة أم لا( كانا منبئين مهمين لتحديد استخدام خدمات الرعاية الصحية الفردية على مستوى المريض.هذه الدراسة هي الدراسة الأولى على الإطلاق التي تستقصي عبء استخدام موارد الرعاية الصحية من قبل مرضى عدوى الجهاز التنفسي في سبعة مراكز للرعاية الصحية الأولية تابعة لمؤسسة الرعاية الصحية الأولية في قطر، ما قد يساعد واضعي السياسات على فهم حجم العبء والتخطيط لمعالجة أفضل لعدوى الجهاز التنفسي في بيئة الرعاية الأولية بدولة قطر

Sources and patterns of education sector financing: options and challenges in Bangladesh

Volume 2, Issue 2, July 200

ENABLING IOT AUTHENTICATION, PRIVACY AND SECURITY VIA BLOCKCHAIN

Although low-power and Internet-connected gadgets and sensors are increasingly integrated into our lives, the optimal design of these systems remains an issue. In particular, authentication, privacy, security, and performance are critical success factors. Furthermore, with emerging research areas such as autonomous cars, advanced manufacturing, smart cities, and building, usage of the Internet of Things (IoT) devices is expected to skyrocket. A single compromised node can be turned into a malicious one that brings down whole systems or causes disasters in safety-critical applications. This dissertation addresses the critical problems of (i) device management, (ii) data management, and (iii) service management in IoT systems. In particular, we propose an integrated platform solution for IoT device authentication, data privacy, and service security via blockchain-based smart contracts. We ensure IoT device authentication by blockchain-based IC traceability system, from its fabrication to its end-of-life, allowing both the supplier and a potential customer to verify an IC’s provenance. Results show that our proposed consortium blockchain framework implementation in Hyperledger Fabric for IC traceability achieves a throughput of 35 transactions per second (tps). To corroborate the blockchain information, we authenticate the IC securely and uniquely with an embedded Physically Unclonable Function (PUF). For reliable Weak PUF-based authentication, our proposed accelerated aging technique reduces the cumulative burn-in cost by ∼ 56%. We also propose a blockchain-based solution to integrate the privacy of data generated from the IoT devices by giving users control of their privacy. The smart contract controlled trust-base ensures that the users have private access to their IoT devices and data. We then propose a remote configuration of IC features via smart contracts, where an IC can be programmed repeatedly and securely. This programmability will enable users to upgrade IC features or rent upgraded IC features for a fixed period after users have purchased the IC. We tailor the hardware to meet the blockchain performance. Our on-die hardware module design enforces the hardware configuration’s secure execution and uses only 2,844 slices in the Xilinx Zedboard Zynq Evaluation board. The blockchain framework facilitates decentralized IoT, where interacting devices are empowered to execute digital contracts autonomously

Vision 2021: The Needs for Women Entrepreneurship, Their Prospects and Constraints in Bangladesh

Development of women entrepreneurship offers excellent opportunities for development of one half of the population and for overall socio-economic progress of the country. This paper examines issues like why women entrepreneurship is needed in Bangladesh to achieve the target set for Vision 2021. What factors influence the strategic growth of women-owned businesses in Bangladesh? What are the characteristics of Bangladeshi women entrepreneurs and their businesses? What have been the greatest obstacles and challenges for women entrepreneurs in Bangladesh? The study shows that the constraints of innovative women entrepreneurship are traditional views and stereotypes about women, lack of science and innovation, lack of substantial investment and women being seen less credible financially than men, lack of access to technical scientific and general business networks, lack of business training, role models and entrepreneurship skills