| 1. |
- Nguyen, Quang Ngoc, 1976-
(författare)
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Understanding and managing cardiovascular disease risk factors in Vietnam : integrating clinical and public health perspectives
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Vietnam, like other low-income countries, is facing an epidemic burden of cardiovascular disease risk factors (CVDRFs). The magnitude and directions of CVDRF progression are matters of uncertainty. Objectives: To describe the epidemiological progression of CVDRFs and the preventive effects of community lifestyle interventions, with reference to the differences in progression of CVDRF patterns between men and women. Methods: The study was conducted during 2001-2009 in nationally representative samples and in a local setting of rural areas of Ba-Vi district, Ha-Tay province. Both epidemiological and interventional approaches were applied: (i) a population-based cross-sectional survey of 2,130 people aged ≥25 years in Thai-Binh and Hanoi; (ii) an individual participant-level meta analysis of 23,563 people aged 24-74 years from multiple similar surveys in 9 provinces around Vietnam; (iii) a 17-month cohort study of 497 patients in a hypertension management programme; (iv) a quasi-experimental trial on community lifestyle promotion integrated with a hypertension management programme, evaluated by surveys of 4,645 people in both intervention and reference communes before and after a 3-year intervention. Main findings: (i) in the general adult population ≥25 years, CVDRFs were common, often clustered within individuals, and increased with age; (ii) the Vietnamese population is facing a growing epidemic of CVDRFs, which are generally not well managed; (iii) it is possible to launch a community intervention in low-resource settings within the scope of a commune-based patient-targeted programme on hypertension management; (iv) community health intervention with comprehensive healthy lifestyle promotion improves blood pressure and some behavioural CVDRFs. Conclusion: Alarming increases in CVDRFs in the general population need comprehensive multi-level prevention strategies, which combine both individual high-risk and population health approaches. The commune-based hypertension-centred management programmes integrated with community health promotion are the initial but essential steps towards comprehensive and effective management of CVDRFs and should be part of an integrated and co-ordinated national program on the prevention and control of chronic diseases in low-resource settings like Vietnam.
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| 2. |
- Danielsson, Tatiana
(författare)
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Further Investigations of Convergence Results for Homogenization Problems with Various Combinations of Scales
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis is based on six papers. We study the homogenization of selected parabolic problems with one or more microscopic scales in space and time, respectively. The approaches are prepared by means of certain methods, like two-scale convergence, multiscale convergence and also the evolution setting of multiscale convergence and very weak multiscale convergence. Paper I treats a linear parabolic homogenization problem with rapid spatial and temporal oscillations in perforated domains. Suitable results of two-scale convergence type are established. Paper II deals with further development of compactness results which can be used in the homogenization procedure engaging a certain limit condition. The homogenization procedure deals with a parabolic problem with a certain matching between a fast spatial and a fast temporal scale and a coefficient passing to zero that the time derivative is multiplied with. Papers III and IV are further generalizations of Paper II and investigate homogenization problems with different types of matching between the microscopic scales. Papers III and IV deal with one and two rapid scales in both space and time respectively. Paper V treats the nonlinearity of monotone parabolic problems with an arbitrary number of spatial and temporal scales by applying the perturbed test functions method together with multiscale convergence and very weak multiscale convergence adapted to the evolution setting. In Paper VI we discuss the relation between two-scale convergence and the unfolding method and potential extensions of existing results. The papers above are summarized in Chapter 4. Chapter 1 gives a brief introduction to the topic and Chapters 2 and 3 are surveys over some important previous results.
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| 3. |
- Fantahun, Mesganaw, 1958-
(författare)
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Mortality and survival from childhood to old age in rural Ethiopia
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis examines ways of establishing cause of death, assessing trends in mortality, and identifying factors that affect mortality and survival among the different population groups in rural and semi-urban Ethiopia. These data are important for health care planning; however, such vital data are unavailable in many developing countries. The study was conducted in Butajira Rural Health Program Demographic Surveillance Site, Ethiopia, where data collection on vital events and related research has been conducted for the last 20 years. This thesis used a cohort and a case referent study preceded by Focus Group Discussion. It also employed a verbal autopsy procedure to identify causes of death. The cohort component used 18 years of surveillance data (1987-2004). The prospective case referent study, carried out in the years 2003-2005, was used to complement the mortality analysis and focused particularly on issues related to household decision making, social capital, and economic status. The main subgroups included were children under-five years old, adults 15-64, and the elderly 65 years and above. Cause of death was ascertained using the Physicians’ Review and InterVA methods. Food shortage and epidemics affected the modest downward trend of mortality. There was a general similarity between the Physicians’ Review and InterVA methods in identifying the major causes of death. About 60% of the deaths were due to pneumonia/sepsis, pulmonary tuberculosis, malaria, and diarrhoea disease/malnutrition. The InterVA method was cheaper and more consistent. Higher rates of HIV/AIDS (11%), tuberculosis (18%), and cardiovascular (9%) mortality were noted in urban areas compared to rural areas. Consistent higher mortality was found in rural areas. Women were disadvantaged by residence and advanced age. Place of residence, illiteracy, widowhood, and not owning a house affected men and women differently, indicating a possible need for gender-specific interventions. Children and women survival is affected by household decision-making; this means efforts to improve women’s involvement in household decision-making (women empowerment) might improve child and women survival in poor settings. Many factors that significantly affect mortality can only be controlled by concerted efforts to improve health and overall development.
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| 5. |
- Aeddula, Omsri, 1993-
(författare)
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Navigating Data Challenges: AI-Driven Decision Support for Product-Service System Development
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Solution providers are transitioning from product-centric models to service-oriented solutions. This shift has led to the rise of Product-Service Systems (PSS), which offer a holistic approach by integrating physical products with associated services. However, the inherent complexity and collaborative nature of PSS development present a significant challenge: information gathering, analysis, and knowledge building. This is further amplified in the early stages of PSS development due to data challenges such as uncertainty, ambiguity, and complexity. This complicates informed decision-making, potentially leading to the risk of sub-optimal outcomes and impacting the success of final offerings.This research proposes an AI-powered data analysis approach to address these data challenges and augment the decision-making process of PSS development. The focus is on supporting early-stage decision-making, as decisions made at this stage greatly impact the success of final solutions. The research investigates how data can be utilized and visualized to extract actionable insights, ultimately facilitating informed decision-making.The presented research demonstrates that AI-powered data analysis effectively supports informed decision-making in early-stage PSS development. By extracting actionable insights from complex data, handling data limitations, and enabling informed strategic decisions, knowledge sharing, and collaboration are facilitated among stakeholders. Furthermore, integrating AI with visualization tools fosters knowledge building and a deeper understanding of system behavior, ultimately leading to more successful PSS solutions. The efficacy of AI-powered data analysis for handling diverse data types across application domains is demonstrated, potentially leading to benefits such as a deeper understanding of system behavior and proactive solution strategies. These advancements contribute to developing decision support systems specifically for PSS development.Overall, this research demonstrates the efficacy of AI-powered data analysis in overcoming data challenges and empowering decision-makers in early-stage PSS development. This translates to more informed choices, leading to the creation of successful and efficient PSS solutions.
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| 6. |
- Akhmetkaliyeva, Raya
(författare)
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Maximal regularity of the solutions for some degenerate differential equations and their applications
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This PhD thesis deals with the study of existence and uniqueness together with coercive estimates for solutions of certain differential equations.The thesis consists of six papers (papers A, B, C, D, E and F), two appendices and an introduction, which put these papers and appendices into a more general frame and which also serves as an overview of this interesting field of mathematics.In the text below the functionsr = r(x), q = q(x), m = m(x) etc. are functions on (−∞,+∞), which are different but well defined in each paper. Paper A deals with the study of separation and approximation properties for the differential operator in the Hilbert space (here is the complex conjugate of ). A coercive estimate for the solution of the second order differential equation is obtained and its applications to spectral problems for the corresponding differential operator is demonstrated. Some sufficient conditions for the existence of the solutions of a class of nonlinear second order differential equations on the real axis are obtained.In paper B necessary and sufficient conditions for the compactness of the resolvent of the second order degenerate differential operator in is obtained. We also discuss the two-sided estimates for the radius of fredholmness of this operator.In paper C we consider the minimal closed differential operator in , where are continuously differentiable functions, and is a continuous function. In this paper we show that the operator is continuously invertible when these coefficients satisfy some suitable conditions and obtain the following estimate for : ,where is the domain of .In papers D, E, and F various differential equations of the third order of the form are studied in the space .In paper D we investigate the case when and .Moreover, in paper E the equation (0.1) is studied when . Finally, in paper F the equation (0.1) is investigated under certain additional conditions on .For these equations we establish sufficient conditions for the existence and uniqueness of the solution, and also prove an estimate of the form for the solution of equation (0.1).
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| 7. |
- Kikonko, Mervis, 1973-
(författare)
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Some new results concerning general weighted regular Sturm-Liouville problems
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this PhD thesis we study some weighted regular Sturm-Liouville problems in which the weight function takes on both positive and negative signs in an appropriate interval [a,b]. With such problems there is the possible existence of non-real eigenvalues, unlike in the definite case (i.e. left or right definite) in which only real eigenvalues exist.This PhD thesis consists of five papers (papers A-E) and an introduction to this area, which puts these papers into a more general frame.In paper A we give some precise estimates on the Richardson number for the two turning point case, thereby complementing the work of Jabon and Atkinson from 1984 in an essential way. We also give a corrected version of their result since there seems to be a typographical error in their paper.In paper B we show that the interlacing property, which holds in the one turning point case, does not hold in the two turning point case. The paper consists of a detailed presentation of numerical results of the case in which the weight function is allowed to change its sign twice in the interval (-1, 2). We also present some theoretical results which support the numerical results. Moreover, a number of new open questions are raised. We also observe that the real and imaginary parts of a non-real eigenfunction either have the same number of zeros in the interval (-1,2) or the numbers of zeros differ by two.In paper C, we obtain bounds on real and imaginary parts of non-real eigenvalues of a non-definite Sturm-Liouville problem, with Dirichlet boundary conditions, thus complementing the results obtained in a paper byBehrndt et.al. from 2013 in an essential way.In paper D we obtain a lower bound on the eigenvalue of the smallest modulus associated with a Dirichlet problem in the general case of a regular Sturm-Liouville problem.In paper E we expand upon the basic oscillation theory for general boundary problems of the form -y''+q(x)y=λw(x)y, on I = [a,b], where q(x) and w(x) are real-valued continuous functions on [a,b] and y is required to satisfy a pair of homogeneous separated boundary conditions at the end-points. Already in 1918 Richardson proved that, in the case of the Dirichlet problem, if w(x) changes its sign exactly once and the boundary problem is non-definite, then the zeros of the real and imaginary parts of any non-real eigenfunction interlace. We show that, unfortunately, this result is false in the case of two turning points, thus removing any hope for a general separation theorem for the zeros of the non-real eigenfunctions. Furthermore, we show that when a non-real eigenfunction vanishes inside I, then the absolute value of the difference between the total number of zeros of its real and imaginary parts is exactly 2.
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| 8. |
- Minh, Hoang Van, 1971-
(författare)
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Epidemiology of cardiovascular disease in rural Vietnam
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In the context of transitional Vietnam, although cardiovascular disease (CVD) has been shown to cause a large burden of mortality and morbidity in hospitals, little is known about the magnitude of its burden, risk factor levels and its relationship with socio-demographic status in the overall population. This thesis provides a preliminary insight into population-based knowledge of the CVD epidemiology in rural Vietnam and contributes to the development of methodologies for monitoring it. The ultimate goal of the work is to facilitate the formulation of evidence-based health interventions for reducing the burden of the CVD epidemic in Vietnam and elsewhere. This work was located in Bavi district, a rural community in the north of Vietnam. Studies on cause-specific mortality and risk factors were conducted within the framework of an ongoing Demographic Surveillance System (DSS) (called FilaBavi). The cause-specific mortality study used a verbal autopsy (VA) approach to identify causes of death in FilaBavi during 1999-2003. The risk factor study, conducted in 2002, employed the WHO STEPwise approach to surveillance of non-communicable disease (NCD) risk factors (WHO STEPS). Findings indicated that Bavi district, as an example of rural Vietnam, was already experiencing high rates of CVD mortality and associated risk factors. Mortality results indicated a substantial proportion of deaths due to CVD, which was the leading cause of death (20% and 25.7% of total mortality in 1999 and 2000, respectively and 32% of adult deaths during 1999-2003), exceeding infectious diseases. Hypertension was found to be a serious problem in terms both of its magnitude (14% of the population) and widespread unawareness (82% of the hypertensives). Smoking prevalence was very high among men (58% current daily smokers) and might be expected to cause a considerable number of future deaths without urgent action. CVD mortality and some risk factors seemed to be rising among disadvantaged groups (women, less educated people and the poor). The combination of DSS and WHO STEPS methodologies was shown to have potential for addressing basic epidemiological questions as to how NCD and CVD mortality and associated risk factors are distributed in populations. Given this evidence, actions to prevent CVD in Bavi and similar settings are clearly urgent. Interventions should be comprehensive and integrated, including both primary and secondary approaches, as well as policy-level involvement. Further studies, continuing on similar lines, plus qualitative approaches and deeper cross-site comparisons, are also needed to give further insights into CVD epidemiology in this type of setting.
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| 9. |
- Aeddula, Omsri, 1993-, et al.
(författare)
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AI-driven Ossification Assessment in Knee MRI : A Product-Service System Development for Informed Clinical Decision-Making
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Background: Traditionally, assessing the degree of ossification in the epiphyseal plate for growth plate development relies on manual evaluation, which can be inefficient due to the complexities of the distal femoral epiphysis anatomy. Existing methods lack efficient detection techniques.Method: This study proposes an AI-based decision support system, designed within a product-service system (PSS) framework, to automate ossification assessment and detection of the distal femoral epiphysis in knee magnetic resonance imaging (MRI) data. The system leverages advanced machine learning techniques, specifically two Convolutional Neural Networks (CNNs), combined with computer vision techniques. This intelligent system analyzes MRI slices to predict the optimal slice for analysis and identify variations in the degree of ossification within individual datasets.Results: The proposed method's effectiveness is demonstrated using a set of T2-weighted gradient echo grayscale knee MRI data. The system successfully detects the complex anatomy of the distal femoral epiphysis, revealing variations in the degree of ossification ranging from completely closed/open to fully open/closed regions.Conclusions: This study presents a robust and efficient AI-based method, integrated within a PSS framework, for measuring the degree of ossification in the distal femoral epiphysis. This approach automates ossification assessment, providing valuable insights for clinical decision-making by clinicians and forensic practitioners. The PSS framework ensures seamless integration of the AI technology into existing workflows.
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| 10. |
- Burtseva, Evgeniya, 1988-
(författare)
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Operators and Inequalities in various Function Spaces and their Applications
- 2016
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This Licentiate thesis is devoted to the study of mapping properties of different operators (Hardy type, singular and potential) between various function spaces.The main body of the thesis consists of five papers and an introduction, which puts these papers into a more general frame.In paper A we prove the boundedness of the Riesz Fractional Integration Operator from a Generalized Morrey Space to a certain Orlicz-Morrey Space, which covers the Adams resultfor Morrey Spaces. We also give a generalization to the case of Weighted Riesz Fractional Integration Operators for a class of weights.In paper B we study the boundedness of the Cauchy Singular Integral Operator on curves in complex plane in Generalized Morrey Spaces. We also consider the weighted case with radial weights. We apply these results to the study of Fredholm properties of Singular Integral Operators in Weighted Generalized Morrey Spaces.In paper C we prove the boundedness of the Potential Operator in Weighted Generalized Morrey Spaces in terms of Matuszewska-Orlicz indices of weights and apply this result to the Hemholtz equation with a free term in such a space. We also give a short overview of some typical situations when Potential type Operators arise when solving PDEs.In paper D some new inequalities of Hardy type are proved. More exactly, the boundedness of multidimensional Weighted Hardy Operators in Hölder Spaces are proved in cases with and without compactification.In paper E the mapping properties are studied for Hardy type and Generalized Potential type Operators in Weighted Morrey type Spaces.
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