291 research outputs found

    Foreword

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    Fund investments are very popular in Sweden. However, we have the impression that despite this popularity, the average fund investor in Sweden does not pay much attention to the importance and possible link of fund’s asset composition features (e.g. Asset class, Holdings, and Geo-exposure) to fund’s performance. Instead, S/he relies on factors such as fees, risk levels, historical performance, etc. in her/his investment decisions. Similarly, academic studies mainly focus on attributes such as funds fees, size, and manager’s skill to explain fund’s performance. Thus there are limited premier academic studies on the relationship between fund’s performance and its asset composition features. The main purpose of this study is to investigate possible causal relationship between the performances of funds with their assets composition features. We study the whole population of 346 Swedish listed mutual funds older than five years for the period 2009-2013. The results of the study provides the investors and analysts with additional decision-making and investment-analysis tools to assist them in making more informed judgment on funds and their expected returns. The results are also useful for fund managers to improve their strategies by refining the combinations of their funds’ asset composition attributes in order to improve the absolute risk-adjusted performance of their funds. Our research philosophy has been based on positivism and objectivism along with functionalist paradigm and we have applied deductive approach to test the theories. We have used quantitative method and collected the funds’ data from public business databases and chosen Jensen’s alpha and Treynor ratio as funds’ risk-adjusted performance measures. We performed Correlation tests and Regression with robust techniques on our data to answer the research question from three aspects, namely asset class (equity, bond, and mixed assets); geo-exposures (Sweden, Global, Europe, and Nordic) and Top-ten holdings’ measures (asset concentration and Treynor of each fund’s passive top-ten sub-portfolio). We conclude that correlations between funds’ risk-adjusted performance and assets composition features are likely to exist. Stronger correlations are observed between the explanatory measures and fund’s relative risk-adjusted performance (fund’s Treynor) as compared to fund’s absolute risk adjusted performance (fund’s Jensen’s alpha). Asset concentration in top-ten holdings and bond asset class are more likely to be in casual relationship with fund’s risk-adjusted performance, whereas Treynor ratio of top-ten holdings’ passive sub-portfolio as well as fund’s geo-exposure do not seem to have strong explanatory power for funds’ absolute performance

    Surrounding buildings and wind pressure distribution on a high-rise building

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    The effect of the surrounding lower buildings on the wind pressure distribution on a high-rise building is investigated by computational fluid dynamics (CFD). When B/H=0.1, it is found that the wind pressure on the windward side was reduced especially on the lower part, but for different layers of surrounding buildings, there was no great difference, which agrees with our previous wind tunnel experiment data. Then we changed the aspect ratio from 0.1 to 2, to represent different airflow regimes: skimming flow (SF), and wake interference (WI). It shows that the average Cp increases when B/H increases. For different air flow regimes, it is found that insignificant difference exists when the number of the building layers is more than 2. From the engineering point of view, it is sufficient to only include the first layer for natural ventilation design by using CFD simulation or wind tunnel experiment

    Quantifying the health burden misclassification from the use of different PM2.5 exposure tier models: A case study of London

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    Exposure to PM2.5 has been associated with increased mortality in urban areas. Hence, reducing the uncertainty in human exposure assessments is essential for more accurate health burden estimates. Here we quantify the misclassification that occurs when using different exposure approaches to predict the mortality burden of a population using London as a case study. We develop a framework for quantifying the misclassification of the total mortality burden attributable to exposure to fine particulate matter (PM2.5) in four major microenvironments (MEs) (dwellings, aboveground transportation, London Underground (LU) and outdoors)in the Greater London Area (GLA), in 2017. We demonstrate that differences exist between five different exposure Tier-models with incrementally increasing complexity, moving from static to more dynamic approaches. BenMap-CE, the open source software developed by the U.S. Environmental Protection Agency, is used as a tool to achieve spatial distribution of the ambient concentration by interpolating the monitoring data to the unmonitored areas and ultimately estimate the change in mortality on a fine resolution. Our results showed that using the outdoor concentration as a surrogate for the total population exposure but ignoring the different exposure concentration that occurs indoors and the time spent in transit, would lead to a misclassification of 1,174 predicted mortalities in GLA. Indoor exposure to PM2.5 is the largest contributor to total population exposure, accounting for 80% of total mortality, followed by the London Underground which contributes 15%, albeit the average percentage of time spent there by Londoners is only 0.4%. We generally confirmed that increasing the complexity and incorporating important microenvironments, such as the highly polluted LU, could significantly reduce the misclassification in health burden assessments

    Analysis of Direct Outdoor Air Cooling Efficency for Combined Variable Air Volume Air-conditioning System in Stores in Cold Climates of China

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    Direct outdoor air cooling contributes a lot not only to the improvement of the indoor air quality but also to the energy saving. Its full use will reduce the water chiller’s running time especially in some stores where cooling load keeps much higher and longer than that in other buildings. A novel air-conditioning system named Combined Variable Air Volume system (CVAV), combining a normal AHU with a separate outdoor air supply system, was proposed firstly by the authors. The most attractive feature of the system is its full utilization of cooling capacity and freshness of outdoor air in the transition period of the year round. On the basis of the obtain of the dynamic cooling loads of the typical shopping malls in different four cities located in cold climates in China with the aid of DOE-2, the possibility of increasing the amount of outdoor air volume of CVAV system in the transition period instead of operating the water chillers was confirmed. Moreover, a new concept, Direct Outdoor Air Cooling Efficiency (DOACE), was defined as the ratio of cooling capacity of outdoor air to the water chiller, indicating the degree of outdoor air’s utilization. And the DOACE of the CVAV was calculated and compared with that of conventional all-air constant volume air-conditioning systems, the results showed that CVAV bear much more energy saving potential with the 10%~19% higher DOACE and it is a kind of energy efficient systems and can improve the indoor air quality as well

    A Bakhtinian reading of fantasy chronotopes in modern children’s fantasy literature

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    Drawing on Bakhtin’s theory of the literary artistic chronotope and the interdisciplinary spatiotemporal theories of geocriticism, this study identifies three particular modes of the fantasy spatiotemporality presented in modern children’s fantasy works. They are the epic chronotope, the “fantastic” time-travel chronotope and the heterotopian chronotope. Each fantasy chronotope is examined in the specific but interrelated textual contexts of selected children’s fantasy works in relation to the three main research questions: (i) How is the fantasy chronotope embodied and strategically deployed in the focused children’s fantasy works? (ii) What ideas and values are conveyed by its syntagmatic interplay with other chronotopes that characterise the textual quotidian world? (iii) How do characters, through their spatiotemporal practices, negotiate with the divergent chronotopic values that converge and wrestle in the textual universes? This study builds on existing works in relation to chronotopic considerations and develops the understanding of the fantasy chronotope in these particular ways: a) It moves the study of the fantasy chronotope from generalities to specific instances, so that the inner diversity of the fantasy spatiotemporal arrangements can be perceived and explored. b) It examines the syntagmatic spatiotemporal relations constructed between the fantasy and the “real” in individual children’s fantasy works and their connotations. In so doing, it reveals how each of the identified fantasy chronotopes can be strategically deployed in fantasy cartographies to convey meanings and values. c) This study also delves into the spatiotemporal embedding of human actions that is distinctively shown in fantasy chronotopes. This is done by reading characters’ spatiotemporal practices in and their negotiations with the projected fantasy worlds. d) Taking Bakhtin’s literary artistic chronotope as the link, my reading of the fantasy chronotopes also demonstrates an interpenetrative and reciprocal relation between fantasy spatiotemporal imaginations and the theoretical interpretations of space and time in geocriticism

    Wind pressure on a single building immersed in a low-jet wind profile

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    This paper for the first time discuss the wind pressure distribution on the building surface immersed in wind profile of low-level jet rather than a logarithmic boundary-layer profile. Two types of building models are considered, low-rise and high-rise building, relative to the low-level jet height. CFD simulation is carried out. The simulation results show that the wind pressure distribution immersed in a low-jet wine profile is very different from the typical uniform and boundary-layer flow. For the low-rise building, the stagnation point is located at the upper level of windward façade for the low-level jet wind case, and the separation zone above the roof top is not as obvious as the uniform case. For the high-rise building model, the height of stagnation point is almost as high as the low-level jet height

    Health and economic benefits of building ventilation interventions for reducing indoor PM2.5 exposure from both indoor and outdoor origins in urban Beijing, China

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    China is confronted with serious PM2.5 pollution, especially in the capital city of Beijing. Exposure to PM2.5 could lead to various negative health impacts including premature mortality. As people spend most of their time indoors, the indoor exposure to PM2.5 from both indoor and outdoor origins constitutes the majority of personal exposure to PM2.5 pollution. Different building interventions have been introduced to mitigate indoor PM2.5 exposure, but always at the cost of energy expenditure. In this study, the health and economic benefits of different ventilation intervention strategies for reducing indoor PM2.5 exposure are modelled using a representative urban residence in Beijing, with consideration of different indoor PM2.5 emission strengths and outdoor pollution. Our modelling results show that the increase of envelope air-tightness can achieve significant economic benefits when indoor PM2.5 emissions are absent; however, if an indoor PM2.5 source is present, the benefits only increase slightly in mechanically ventilated buildings, but may show negative benefit without mechanical ventilation. Installing mechanical ventilation in Beijing can achieve annual economic benefits ranging from 200yuan/capita to 800yuan/capita if indoor PM2.5 sources exist. If there is no indoor emission, the annual benefits above 200yuan/capita can be achieved only when the PM2.5 filtration efficiency is no less than 90% and the envelope air-tightness is above Chinese National Standard Level 7. Introducing mechanical ventilation with low PM2.5 filtration efficiency to current residences in urban Beijing will increase the indoor PM2.5 exposure and result in excess costs to the resident

    Effect of building gap to improve pedestrian comfort levels and ventilation

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    Rapid rates of urbanization have resulted into increased concerns of urban environment. Amongst them, wind and thermal comfort levels for pedestrians have attracted research interest. In this regards, urban wind environment is seen as a crucial components that can lead to improved thermal comfort levels for pedestrian population. High rise building in modern urban setting causes high levels of turbulence that renders discomfort to pedestrians. Additionally, a higher frequency of high ris e buildings at a particular region acts as a shield against the wind flow to the lower buildings beyond them resulting into higher levels of discomfort to users or residents. Studies conducted on developing wind flow models using Computational Fluid Dynami cs (CFD) simulations have revealed improvement in interval to height ratios can results into improved wind flow within the simulation grid. However, high value and demand for land in urban areas renders expansion to be an impractical solution. Nonetheless, innovative utilization of architectural concepts can be imagined to improve the pedestrian comfort levels through improved wind permeability. This paper assesses the possibility of through-building gaps being a solution to improve pedestrian comfort levels
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