112 research outputs found

    Cross-View Image Synthesis using Conditional GANs

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    Learning to generate natural scenes has always been a challenging task in computer vision. It is even more painstaking when the generation is conditioned on images with drastically different views. This is mainly because understanding, corresponding, and transforming appearance and semantic information across the views is not trivial. In this paper, we attempt to solve the novel problem of cross-view image synthesis, aerial to street-view and vice versa, using conditional generative adversarial networks (cGAN). Two new architectures called Crossview Fork (X-Fork) and Crossview Sequential (X-Seq) are proposed to generate scenes with resolutions of 64x64 and 256x256 pixels. X-Fork architecture has a single discriminator and a single generator. The generator hallucinates both the image and its semantic segmentation in the target view. X-Seq architecture utilizes two cGANs. The first one generates the target image which is subsequently fed to the second cGAN for generating its corresponding semantic segmentation map. The feedback from the second cGAN helps the first cGAN generate sharper images. Both of our proposed architectures learn to generate natural images as well as their semantic segmentation maps. The proposed methods show that they are able to capture and maintain the true semantics of objects in source and target views better than the traditional image-to-image translation method which considers only the visual appearance of the scene. Extensive qualitative and quantitative evaluations support the effectiveness of our frameworks, compared to two state of the art methods, for natural scene generation across drastically different views.Comment: Accepted at CVPR 201

    A systematic review of the factors - enablers and barriers - affecting e-learning in health sciences education

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    Background: Recently, much attention has been given to e-learning in higher education as it provides better access to learning resources online, utilising technology – regardless of learners’ geographical locations and timescale – to enhance learning. It has now become part of the mainstream in education in the health sciences, including medical, dental, public health, nursing, and other allied health professionals. Despite growing evidence claiming that e-learning is as effective as traditional means of learning, there is very limited evidence available about what works, and when and how e-learning enhances teaching and learning. This systematic review aimed to identify and synthesise the factors – enablers and barriers – affecting e-learning in health sciences education (el-HSE) that have been reported in the medical literature. Methods: A systemic review of articles published on e-learning in health sciences education (el-HSE) was performed in MEDLINE, EMBASE, Allied & Complementary Medicine, DH-DATA, PsycINFO, CINAHL, and Global Health, from 1980 through 2019, using ‘Textword’ and ‘Thesaurus’ search terms. All original articles fulfilling the following criteria were included: (1) e-learning was implemented in health sciences education, and (2) the investigation of the factors – enablers and barriers – about el-HSE related to learning performance or outcomes. Following the PRISMA guidelines, both relevant published and unpublished papers were searched. Data were extracted and quality appraised using QualSyst tools, and synthesised performing thematic analysis. Results: Out of 985 records identified, a total of 162 citations were screened, of which 57 were found to be of relevance to this study. The primary evidence base comprises 24 papers, with two broad categories identified, enablers and barriers, under eight separate themes: facilitate learning; learning in practice; systematic approach to learning; integration of e-learning into curricula; poor motivation and expectation; resource-intensive; not suitable for all disciplines or contents, and lack of IT skills. Conclusions: This study has identified the factors which impact on e-learning: interaction and collaboration between learners and facilitators; considering learners’ motivation and expectations; utilising user-friendly technology; and putting learners at the centre of pedagogy. There is significant scope for better understanding of the issues related to enablers and facilitators associated with e-learning, and developing appropriate policies and initiatives to establish when, how and where they fit best, creating a broader framework for making e-learning effective

    Towards a South Asian common currency: Evidence from macroeconomic shocks

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    My paper empirically assesses suitability of the South Asian common currency by testing for symmetry of underlying shocks. Following Mundell’s (1961) seminal work, a key precondition for the formation of a successful monetary union is that member countries face similar types of shocks for coordinated macroeconomic policy response, which paves the way for a currency union. I apply structural vector auto regression (SVAR) approach to determine the nature of shocks affecting the South Asian nations and to find out whether the South Asian Association for Regional Cooperation (SAARC) forms an optimal currency area (OCA)

    Investigation of Perforated Ducted Propellers to use with a UAV

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    Unmanned Aerial Vehicle (UAV) is any flying vehicle which is not controlled by actual human pilots sitting in the cockpit but is installed with proper avionics that can either fly autonomously or by using the commands from its base. Some rotorcraft UAVs use a ducted propeller for two main reasons- safety and to increase the thrust produced by the propellers. While ducted rotors can increase the thrust produced, it also adds weight to the UAV. It was therefore hypothesized that by removing part of the duct materials (i.e. adding perforations in the duct) would benefit from both decreased duct weight and increased thrust. However, it is not clear how much trade-off would be between these two factors. Hence, the objective of this study is to explore the relationship between the change of thrust and addition of different numbers or sizes of perforations. Cases with and without duct, and duct with perforations were simulated using a commercial computational fluid dynamic (CFD) software Ansys/Fluent. The physics of the rotating propeller was modeled by a simplified disc with a pressure jump across an infinitesimal volume. Three different RPM speeds of the propellers were simulated by varying the strength of the pressure jump. The results show that the thrust decreases as the duct is added. As perforations are added, the result shows that with more perforations (i.e. more open area on the duct wall), the thrust increases accordingly until the thrust reaches a maximum value without the duct. The result is in contrast to a published experimental data stating that installation of duct can increase thrust. It is speculated that the current duct with a flat wall has caused such difference from the experimental data. Further study is recommended to continue more detailed computational simulation using a duct with cambered airfoil configuration to reduce the aerodynamic losses

    Methodological and practical viewpoints of qualitative-driven mixed method design: The case of decentralisation of primary healthcare services in Nepal

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    Background Although considerable attention has been paid to the use of quantitative methods in health research, there has been limited focus on decentralisation research using a qualitative-driven mixed method design. Decentralisation presents both a problematic concept and methodological challenges, and is more context-specific and is often multi-dimensional. Researchers often consider using more than one method design when researching phenomena is complex in nature. Aim To explore the effects of decentralisation on the provision of primary healthcare services. Methods Qualitative-driven mixed method design, employing three methods of data collections: focus group discussions (FGDs), semi-structured interviews (SSIs) and participant observations under two components, that is, core component and supplementary components were used. Four FGDs with health service practitioners, three FGDs with district stakeholders, 20 SSIs with health service users and 20 SSIs with national stakeholders were carried out. These were conducted sequentially. NVivo10, a data management program, was utilised to code the field data, employing a content analysis method for searching the underlying themes or concepts in the text material. Findings Both positive and negative experiences related to access, quality, planning, supplies, coordination and supervision were identified. Conclusion This study suggests some evidence of the effects of decentralisation on health outcomes in general, as well as filling a gap of understanding and examining healthcare through a qualitative-driven mixed methods approach, in particular. Future research in the area of qualitative in-depth understanding of the problems (why decentralisation, why now and what for) would provoke an important data set that benefits the researchers and policy-makers for planning and implementing effective health services

    Primary Healthcare: A ‘Jigsaw’ In Reform of the Health Services

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    Health service reform is on the policy agenda throughout the world. Since the Declaration of Alma-Ata in 1978, much of the discussion about the role of primary healthcare (PHC) in health service reform has centred on the political attraction to decentralised health systems. The primary goals of PHC are to make health services effective and efficient in the improvement of people’s health by focusing on: enhancing health status; reforming health service delivery, healthcare provisions and financial sustainability; and strengthening the local and national health services [3]. The philosophical commitment of the Alma-Ata declaration was that people or service users have the right to access essential and universal healthcare services without any personal and institutional constraints

    Three Essays in Applied Economics and Policy Analysis

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    This dissertation consists of three essays. The first essay empirically investigates whether South Asian countries constitute an optimum currency area (OCA) by applying a structural vector auto-regression (SVAR) model to trace global, regional, and domestic shocks. Variance decomposition shows that domestic shocks dominate regional and global shocks, which contrasts with the findings for the European Union countries, used as a basis for comparison. This paper concludes that at the present time the South Asian region as a whole does not meet the prerequisite conditions of an OCA. The loss of an autonomous monetary instrument can outweigh the benefits of a common currency.The second essay investigates the effect of extended unemployment insurance (UI) coverage in the United States in recent years on job search. The U.S. government extended UI benefits in several phases in 2008-2009, increasing the duration of the benefits to a maximum of 99 weeks, up from the regular 26 weeks. Using the American Time Use Survey (ATUS) data, I find that women are more sensitive to the extended UI benefits than men. Difference-in-differences estimation shows that the average effect of the UI extensions for women is over a 10 percentage points decline in the probability of job search. However, I do not find any statistically significant effect on men.In the third essay, I study the evolution of relative wages, and quality of school teachers in the U.S. over the past half-century. I analyze the quality through the prism of a Roy (1951) model of occupational choice. The estimates imply that those selecting to be teachers are more able workers than those schools would see from random assignment. However, the ability distribution of female teachers is on the decline, while that of non-teachers has steadily been rising. I supplement the Roy model with an examination of the teachers\u27 relative cognitive attributes (measured by standardized test scores). I find that teachers have lower average cognitive ability than that of non-teachers. And, the decline in the quality comes on the heels of the declining relative wage. I show that lower pay of female teachers than that of non-teachers is not a permanent phenomenon, but a new trend emerging from 1990 onwards. To seek explanation for the rising wage gap, I use a model of the rising demand for skills in the non-teaching sector, and find a secular demand for the skills
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