11 research outputs found

    Assessing for the volatility of the Saudi, Dubai and Kuwait stock markets: time series analysis (2005-2016)

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    The Kuwait, UAE and Saudi stock markets, alongside five specific firms from the latter, provided the indicator data for analysing market volatility. Autoregressive integrated moving average (ARIMA), Bayesian and Akaike analysis, Ljung-Box Q test, Partial autocorrelation function (PAC) and autocorrelation were the unit root tests applied, alongside matrix error, in this quantitative research. The study aims were to: assess weak-natured efficiency; contrast stock markets’ efficiency; explore market efficiency changes as time progresses. Statistics regarding matrices errors enabled variables influencing market efficiency to be established. Agreement on market efficiency has not been reached by researchers, with one shortcoming of EMH being lack of acknowledgement that an explored time frame may be characterised by varying efficiency levels. Consequently, the EMH and financial conduct have been subject to historiography, yet the connection between EMH and the financial behaviour model has not been the focus of studies using historical data. Accordingly, this research shortcoming tackled through this study, with the company-linked variables influencing stock market efficiency being identified through a literature review. Further, this study prospects identified, with the ongoing development of market efficiency and acceptance of inefficiency and efficiency’s simultaneous presence being the outcome. Finally, liberalisation, financial crises and reform in the Middle East and North Africa (MENA) region is a focus lacking in the extant research, with this study offering a further contribution in this regard. The study reveals that, with five companies and all countries characterised by market inefficiencies, which also changed as time progressed. Foremost efficiency characterised DSM, with SSM second, based on contrasting the obtained data’s random walk. The overall index had less efficiency than the specific firms. Concerning variables, SSM mark efficiency was not enhanced via crises or liberalisation, although it was by reform. Further, the research explains the results’ implications

    Impedance Pneumography for the Nocturnal Assessment of Lower Airway Obstruction

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    Tidal breathing analysis is a lung function technique suggested for infants and children who are unable to cooperate with forced spirometry. This technique aims to quantify lower airway obstruction from average changes in the shape or the breath-to-breath variations of the tidal breathing flow-volume loop (TBFV) profiles. If tidal airflow is recorded with a mouth pneumotachograph (PNT), tidal breathing analysis finds the same limitations as other alternatives to spirometry. These are typically the need for sedation and the assessment of lung function only for sort times at the hospital. Recent improvements in impedance pneumography (IP) enable for the first time the continuous non-invasive monitoring of respiratory airflow overnight. This can improve the analysis of tidal breathing by capturing circadian and nocturnal worsening in lower airway obstruction. However, due to the lack of previous methods recording nocturnal airflow, little is known about how the interaction of sleep physiology and lower airway obstruction is reflected in the shape and variability of tidal breathing. This thesis reviews the literature regarding shape and variability analysis of tidal breathing during lower airway obstruction, sleep, or maturation. The thesis also extends this knowledge by presenting four original publications. The first publication describes a technical improvement in the IP method. The other three study the nocturnal TBFV’s shape in wheezing infants and children, and the nocturnal TBFV’s variability in healthy children. Both the literature and the results agree that for the TBFVs’ shape, increasing lower air- way obstruction advances the peak of expired flow and turns the middle part from convex to concave. However, these changes occur at a different degree of obstruction for differ- ent subjects depending on the compensation strategy that they have chosen. In infants, changes putatively occur at a higher degree of obstruction because most of the expiration is controlled by the respiratory musculature. During rapid eye movement (REM) sleep, changes putatively occur at a lower degree of obstruction because muscle atony limits the compensation strategies. For the variability of TBFVs, increasing lower airway obstruction decreases the variability in the early part of expiration in the long term (the whole night). However, the short-term variability is dominated by the stage-dependent variations in the respiratory drive. The thesis concludes that, at the present, tidal breathing analysis can estimate lower airway obstruction but cannot quantify its degree with accuracy. However, nocturnal IP recordings are easy to conduct and can serve as a first-line diagnosis or for the monitoring of disease progression. Nonetheless, future improvements in signal processing and the understanding of the tidal airflow signal can easily increase the accuracy and find new applications

    Efficient Reinforcement Learning using Gaussian Processes

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    This book examines Gaussian processes (GPs) in model-based reinforcement learning (RL) and inference in nonlinear dynamic systems. First, we introduce PILCO, a fully Bayesian approach for efficient RL in continuous-valued state and action spaces when no expert knowledge is available. PILCO learns fast since it takes model uncertainties consistently into account during long-term planning and decision making. Thus, it reduces model bias, a common problem in model-based RL. Due to its generality and efficiency, PILCO is a conceptual and practical approach to jointly learning models and controllers fully automatically. Across all tasks, we report an unprecedented degree of automation and an unprecedented speed of learning. Second, we propose principled algorithms for robust filtering and smoothing in GP dynamic systems. Our methods are based on analytic moment matching and clearly advance state-of-the-art methods

    Adaptive market hypothesis and calendar anomalies in selected African stock markets.

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    Doctoral Degree. University of KwaZulu-Natal, Durban.It takes a theory to beat a theory. However, whether the adaptive market hypothesis (AMH) offers better explanations for stock return behaviour than the popular efficient market hypothesis (EMH) still remains a question for serious empirical investigation. This question informed the analyses of efficiency and calendar anomalies in the selected African stock market, namely the Nigerian Stock Exchange (NGSE), the Johannesburg Stock Exchange (JSE), the Stock Exchange of Mauritians (SEM), the Casablancan Stock Exchange (MOSE) and the Tunisian Stock Exchange (TSE) with the sample period spanning from January 1998 to February 2018. The first objective of this study is to investigate whether market efficiency changes in cyclical version over time, according to the AMH. The second objective is to evaluate the effect of market conditions (up, down, bull, bear, normal) on return predictability. The third objective is to analyse whether calendar anomalies disappear and reappear over time. The fourth objective is to determine how the anomalies behave under different bull and bear market conditions. Various linear testing tools such as the variance ratio test, the autocorrelation test, the unit root tests and the nonlinear of BDS were implemented in rolling window approach to track time-variation in efficiency. A dummy regression model was used to evaluate the market condition effect on return predictability. This study also explored rolling window analyses of several alternative variants of nonlinear models of the GARCH family, to track variation in the behaviour of days-of-the-week (DOW), months-of-the-year (MOY) and intra-month effects. Lastly, the study modelled the switching behaviour of the calendar anomalies under bull and bear conditions by using the Markov switching model (MSM), which is able to generate regime-specific regression results for the calendar anomalies under consideration. Findings from the various linear and nonlinear tests revealed that there are cycles of significant linear and nonlinear dependence and independence in each of the five markets, suggesting bouts of predictability and unpredictability. The regression analyses of return predictability against series of market condition dummies revealed that highIt takes a theory to beat a theory. However, whether the adaptive market hypothesis (AMH) offers better explanations for stock return behaviour than the popular efficient market hypothesis (EMH) still remains a question for serious empirical investigation. This question informed the analyses of efficiency and calendar anomalies in the selected African stock market, namely the Nigerian Stock Exchange (NGSE), the Johannesburg Stock Exchange (JSE), the Stock Exchange of Mauritians (SEM), the Casablancan Stock Exchange (MOSE) and the Tunisian Stock Exchange (TSE) with the sample period spanning from January 1998 to February 2018. The first objective of this study is to investigate whether market efficiency changes in cyclical version over time, according to the AMH. The second objective is to evaluate the effect of market conditions (up, down, bull, bear, normal) on return predictability. The third objective is to analyse whether calendar anomalies disappear and reappear over time. The fourth objective is to determine how the anomalies behave under different bull and bear market conditions. Various linear testing tools such as the variance ratio test, the autocorrelation test, the unit root tests and the nonlinear of BDS were implemented in rolling window approach to track time-variation in efficiency. A dummy regression model was used to evaluate the market condition effect on return predictability. This study also explored rolling window analyses of several alternative variants of nonlinear models of the GARCH family, to track variation in the behaviour of days-of-the-week (DOW), months-of-the-year (MOY) and intra-month effects. Lastly, the study modelled the switching behaviour of the calendar anomalies under bull and bear conditions by using the Markov switching model (MSM), which is able to generate regime-specific regression results for the calendar anomalies under consideration. Findings from the various linear and nonlinear tests revealed that there are cycles of significant linear and nonlinear dependence and independence in each of the five markets, suggesting bouts of predictability and unpredictability. The regression analyses of return predictability against series of market condition dummies revealed that high predictability is associated with the bull, volatility and financial crisis periods, especially in NGSE, SEM and TSE and not in others. It suggests that the effect of market condition cannot be generalised for all markets. Further, rolling GARCH estimations showed that calendar anomalies disappear and reappear over time in line with the AMH. The evaluation of calendar anomaly under AMH provides a clearer picture of the behaviour of African stock markets as adaptive. Finally, the empirical results revealed that regime-switching is an important feature of calendar anomalies and that a calendar anomaly that is found in a bull regime tends to disappear or weaken in a bear regime and vice versa, depending on the market and the calendar anomaly in question. This study adds to the extant literature on the AMH in Africa and global markets. First, it shows that African stock markets are adaptive. Thus, it is more appropriate to describe African markets as adaptive markets rather than inefficient markets. Secondly, it provides empirical evidence of efficiency cum market condition in African stock markets. Thirdly, the study represents a timely contribution on calendar anomalies under AMH in African stock market. Fourthly, by evaluating DOW, MOY and HOM effects under AMH, this study extends the existing works on Monday and January effects in developed markets. Additionally, this study shows the usefulness of MSM in evaluating calendar anomalies under AMH

    On the maintenance of weak meridional temperature gradients during warm climates

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    Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2005.Includes bibliographical references (p. 238-248).This thesis examines the dynamics of equable climates. The underlying physics of two mechanisms by which weak meridional temperature gradients might be maintained are studied. First, I examine the evolution of stratospheric dynamics and winter temperatures when the surface temperature gradient and tropospheric eddy energy decrease in order to assess whether large-scale conditions are more favorable for polar stratospheric cloud formation. Second, I examine whether the combination of high carbon dioxide and interactive, tropical cyclone dependent ocean mixing is sufficient to maintain a weak temperature gradient. I examine planetary wave generation, the energetics of the general circulation, and vertical wave propagation in a general circulation model with a resolved stratosphere forced with a weak surface temperature gradient. Compared to the present climate, transient eddy energy decreases, but stationary eddy energy does not. The polar tropopause rises, which supports a weaker temperature gradient in the lower stratosphere, a weaker stratospheric jet, and an increase in the wave activity vertically propagating into the stratosphere.(cont.) As a result, the residual mean circulation strengthens and temperatures in the polar stratosphere change little even when the surface temperature gradient is quite weak. Temperatures in the Arctic polar vortex remain much warmer than radiative equilibrium, inhibiting large-scale polar stratospheric cloud formation. The height of the extratropical tropopause rises and the tropospheric lapse rate follows a moist adiabat when surface temperatures are warm, suggesting convection plays a significant role in setting extratropical tropospheric stratification during warm climates. The second part of the thesis addresses the role of tropical cyclone induced mixing in the oceans' general circulation. I examine the sensitivity of the oceans' meridional overturning circulation and heat flux to the locations at which mixing occurs. When confined to the tropical Atlantic, a robust single-basin circulation can be maintained, but the Indian and Pacific become quiescent, cut off from the dynamics occurring in the Atlantic. Mixing isolated in the tropical Pacific, however, can support a global circulation by mechanically lifting deep fluid parcels formed in the Atlantic, raising their potential energy.(cont.) The oceans' total heat flux is found to be sensitive to mixing in the tropics, in both the Atlantic and the Pacific, and in the upper 400 meters of the ocean. Coupling mixing with a measure of tropical cyclone intensity and frequency creates a positive feedback between climate and the poleward energy flux. When combined with a parameterization of the background mixing that evolves with stratification, a warmer, less stratified ocean can support a stronger diapycnal mixing during warm climates with high loads of carbon dioxide. In these simulations, tropical cyclones are stronger and more frequent, providing an increased energy source for more vigorous mixing in the tropical oceans. Combined with a stratification-dependent mixing scheme, such mixing provides a sufficiently strong heat flux that is able to maintain weak sea surface temperature gradients.by Robert Lindsay Korty.Ph.D

    Social work with airports passengers

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    Social work at the airport is in to offer to passengers social services. The main methodological position is that people are under stress, which characterized by a particular set of characteristics in appearance and behavior. In such circumstances passenger attracts in his actions some attention. Only person whom he trusts can help him with the documents or psychologically

    Factors Influencing Customer Satisfaction towards E-shopping in Malaysia

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    Online shopping or e-shopping has changed the world of business and quite a few people have decided to work with these features. What their primary concerns precisely and the responses from the globalisation are the competency of incorporation while doing their businesses. E-shopping has also increased substantially in Malaysia in recent years. The rapid increase in the e-commerce industry in Malaysia has created the demand to emphasize on how to increase customer satisfaction while operating in the e-retailing environment. It is very important that customers are satisfied with the website, or else, they would not return. Therefore, a crucial fact to look into is that companies must ensure that their customers are satisfied with their purchases that are really essential from the ecommerce’s point of view. With is in mind, this study aimed at investigating customer satisfaction towards e-shopping in Malaysia. A total of 400 questionnaires were distributed among students randomly selected from various public and private universities located within Klang valley area. Total 369 questionnaires were returned, out of which 341 questionnaires were found usable for further analysis. Finally, SEM was employed to test the hypotheses. This study found that customer satisfaction towards e-shopping in Malaysia is to a great extent influenced by ease of use, trust, design of the website, online security and e-service quality. Finally, recommendations and future study direction is provided. Keywords: E-shopping, Customer satisfaction, Trust, Online security, E-service quality, Malaysia

    2007-2008 Course Catalog

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    2007-2008 Course Catalo

    Proceedings of the WABER 2017 Conference

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    The scientific information published in peer-reviewed outlets carries special status, and confers unique responsibilities on editors and authors. We must protect the integrity of the scientific process by publishing only manuscripts that have been properly peer-reviewed by scientific reviewers and confirmed by editors to be of sufficient quality. I confirm that all papers in the WABER 2017 Conference Proceedings have been through a peer review process involving initial screening of abstracts, review of full papers by at least two referees, reporting of comments to authors, revision of papers by authors, and reevaluation of re-submitted papers to ensure quality of content. It is the policy of the West Africa Built Environment Research (WABER) Conference that all papers must go through a systematic peer review process involving examination by at least two referees who are knowledgeable on the subject. A paper is only accepted for publication in the conference proceedings based on the recommendation of the reviewers and decision of the editors. The names and affiliation of members of the Scientific Committee & Review Panel for WABER 2017 Conference are published in the Conference Proceedings and on our website www.waberconference.com Papers in the WABER Conference Proceedings are published open access on the conference website www.waberconference.com to facilitate public access to the research papers and wider dissemination of the scientific knowledge

    Infective/inflammatory disorders

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