Universal Denoising Networks : A Novel CNN Architecture for Image Denoising

We design a novel network architecture for learning discriminative image models that are employed to efficiently tackle the problem of grayscale and color image denoising. Based on the proposed architecture, we introduce two different variants. The first network involves convolutional layers as a core component, while the second one relies instead on non-local filtering layers and thus it is able to exploit the inherent non-local self-similarity property of natural images. As opposed to most of the existing deep network approaches, which require the training of a specific model for each considered noise level, the proposed models are able to handle a wide range of noise levels using a single set of learned parameters, while they are very robust when the noise degrading the latent image does not match the statistics of the noise used during training. The latter argument is supported by results that we report on publicly available images corrupted by unknown noise and which we compare against solutions obtained by competing methods. At the same time the introduced networks achieve excellent results under additive white Gaussian noise (AWGN), which are comparable to those of the current state-of-the-art network, while they depend on a more shallow architecture with the number of trained parameters being one order of magnitude smaller. These properties make the proposed networks ideal candidates to serve as sub-solvers on restoration methods that deal with general inverse imaging problems such as deblurring, demosaicking, superresolution, etc.Comment: Camera ready paper to appear in the Proceedings of CVPR 201

A new gilded age : wealth accumulation in the modern world

Issues of wealth inequality have been the subject of considerable public interest and inquiry in recent years. The Great Recession of 2008 in the United States (US) made many question the extent to which the global economic system not only caused economic hardship but also managed to create a class of ultra-rich in the US and across the globe. Much focus in popular discourse has centred on the degree to which a group of individuals is able to wield enormous economic influence with a concomitant concentration of wealth holdings. In general, mainstream economics has largely played down this aspect of the capitalist system; instead, the poverty aspect of wealth distribution has garnered the attention of most economists. This thesis seeks to establish the ultra-rich as an area worthy of study by focusing on various dimensions that have affected wealth accumulation and brought about an era of unprecedented concentration of wealth at a global level. As a project largely bereft of contemporary prior work, the thesis seeks to explore and establish three key elements of modern wealth accumulation, particularly in its extreme form. Firstly, what are the general trends that signify the emergence of an economic elite across the globe, how has this elite evolved, and how are they distributed across countries and sectors of the economy? Here, the analytical approach adopted is one often utilised in historical economic studies of, for example, the US Gilded Age of the late 1800s. Major findings include that the US continues to lead the world in the generation of individuals with extreme wealth holdings, followed by Western Europe. Developing countries, however, provide a substantial portion of the increases observed. Inheritance continues to play a major role in the existence of billionaires in many regions of the globe, but its role has diminished at a global level, mainly driven by the influx of nouveau riche from China and Russia, as well as from the US. The majority of new wealth is concentrated in finance and real estate, followed by the consumer discretionary sector. These trends observed both before and after the Global Financial Crisis (GFC) of 2008. Further, the data reveal a high degree of survival among the great fortunes, and especially of fortunes based on finance. Secondly, the determinants of wealth accumulation are explored. Utilising an accounting identity of household wealth, issues of savings and consumption, financialisation, the structure of top incomes, particularly the relative importance between capital and earned income are considered. Across all facets, the wealthy increasingly exhibit and exploit behaviours and actions that ensure persistence of their wealth stock while the poorest are being further disadvantaged. Thirdly, the empirical research in this thesis also considers the role of risk aversion and whether it varies with the level of wealth observed. Applying a mean-variance-based measure of relative risk aversion (RRA) to an Australian household micro panel derived from the Household, Income and Labour Dynamics in Australia1 (HILDA) survey, the level of risk aversion of Australia’s household financial portfolios is estimated. Controlling for various socio-economic characteristics, the present study explores whether risk aversion heterogeneity is a function of wealth heterogeneity. In contrast to most studies, it finds evidence of very high risk aversion among the majority of poor households but vastly lower risk aversion among the high percentiles in the wealth distribution. After applying a first differences model across three survey waves spanning 2002 to 2010, risk tolerance is found to increase significantly with wealth. Risk tolerance is positively associated with mortgage payments, but rental payments have no relationship. In addition, there is no evidence that holding a university education has any discernible impact on risk aversion. The study also elicited some preliminary findings on the impact of financial advice on observed risk aversion. Financial advice is found to accentuate risk aversion, particularly among the wealthiest households. These findings have potential implications for the distribution of wealth in Australia, which has received renewed interest. Finally, the sources of wealth across seven advanced economies are explored, with particular emphasis on the role of new and inherited wealth. Despite the consistent increases in the ultra-rich across these countries, there is a significant element of heterogeneity in the degree to which inheritance or new wealth dominates in a given country or region. Further, there is an element of variation in terms of the extent of the role of certain sectors in the rise of the ultra-rich. Across North America, financial services have played the dominant role in bolstering the population of billionaires, with much of the growth in diversified financials followed by property. This thesis seeks to situate the trends within the context of the sweeping historical macroeconomic, social and institutional changes that have been wrought particularly since the end of the Second World War

Institutional Complementarities in the Performance of UK and French Cooperative Firms: a Comparative Analysis

This thesis attempts to identify institutional arrangements that allow cooperative firms to overcome the underinvestment problem identified in the theoretical literature. The comparative institutional analysis focuses on internal and external financial arrangements that provide cooperative firms with equity and debt capital respectively, and is conducted in two different institutional environments, the UK and France. In each context, cooperative firms are separated into successful and struggling forms, depending on their performance, as captured in their turnover, size and dissolution rates. Using the concept of institutional complementarities, the empirical investigation examines the effects of internal and external financial arrangements on the creation and growth of the successful and struggling cooperative firms in the UK and France. Annual regional entry flows are used for the entry models for the periods 2005-2015 and 2006-2014 respectively for the UK and France. Firm-level panel data are used for the growth models for the periods 2008-2016 for the UK and 2007-2016 for France. The findings regarding the effect of external financial arrangements on the growth of cooperative firms are consistent with previous studies on Italian cooperatives, which indicate that the growth of cooperative firms is greater in provinces with relatively higher local financial development. The finding regarding the effects of internal financial arrangements on the growth of cooperatives also align with propositions derived from the literature on the hybridization of cooperative firms, which shows that the integration of features of capitalist firms into traditional cooperative forms has helped these firms mitigate some of their chronic problems and increased their chances of survival. Cooperative firms that are able to reach high hybridization levels are successful because they overcome the underinvestment problem by the utilization of internal financial arrangements, while cooperative firms that present low hybridization levels are much more dependent on supportive external financial arrangements and tend to struggle. Furthermore, this research contributes to the literature by providing evidence for the importance of the development of the legislative framework around worker cooperative firms

Investigation and Prediction of Spiral Wound Reverse Osmosis Membrane Performance

In this work an analytical solution for the performance of the spiral wound modules is presented for sea-water as feed. This analysis takes into account pressure losses in both permeate and brine channels, the effect of concentration polarization and the concentration gradient along the membrane. A five parameters model is introduced. These parameters are; kfb (brine friction parameter), kfp (permeate friction parameter), k1 (water permeability coefficient), k (mass transfer coefficient), k2 (solute permeability coefficient)