119 research outputs found
A Pragmatic Approach to Testing Issues in a Mobile Platform that Does Not Yet Exist:The CAMMP Story
No full textThis paper reports on user studies conducted in a project dealing with a converged mobile rich media platform. We address the questions of the selection of test methods and their application through an iterative process. We argue that a varying degree of simulation of test variables such as the environment, the service or the mobile device behavior optimizes the evaluation in terms of cost-efficiency and results quality, while providing flexibility and ease of use to the researchers conducting the evaluations
Converged Mobile Media: Evaluation of an Interactive User Experience
No full textThis paper describes a PhD thesis exploring various aspects of theend user experience with mobile rich media services. First, theauthor briefly introduces the background fields that frame thestudy. Three research questions are then formulated and theirscientific contribution is justified. Subsequently the authorproposes a methodology to investigate these questions and reportson two initial user studies. Finally, the thesis' ongoing work andintended future steps are introduced
Studies on the toxic effects of La3+ to Tetrahymena thermophila by microcalorimetry
No full textThe toxic effects of La3+ on Tetrahymena thermophila have been studied by microcalorimetry at 28 degrees C. The metabolic rate constant (r) and peak time were linked to the concentration of La3+. The changes of metabolic rate constant indicated that low-concentration La3+ (0-75 mg/L) had no significant effects on the metabolism of Tetrahymena cells but high-concentration La3+ (100-175 mg/L) could inhibit their metabolism. From the results obtained by cell counting and fluorescence depolarization measurements, the inhibition of metabolism resulted from the decrease in cell number and the reduction in cell membrane fluidity. According to the results, it is clear that the metabolic mechanism of Tetrahymena cells has been changed with the addition of high-concentration La3+. In addition, microcalorimetry of Tetrahymena could be a sensible, easy-to-use, and convenient method for monitoring the potential effects of rare earth elements on cells and the freshwater ecosystem
Interpretable Parametric Modelling of the Heart based on ECG Signals
No full textAtrial fibrillation (AF) is one of the most common heart diseases. Billions of people have suffered from it in the world. Although it can lead to terrible complications such as stroke and heart failure, the underlying mechanisms of it are still under-explored. Besides, there is no so-called optimal therapy for the patients. As the disease is progressive, it is important to detect it in an early stage. To develop methods for understanding and detecting AF, the interpretable parametric model can be an option. This model can provide physiological information at the signal level. In this case, the electrocardiogram, as the most commonly used invasive measurement of cardiac conditions, can be the data to model the heart structure and cardiac activities.This thesis proposes an interpretable parametric model based on P-waves extracted from the ECG signals. Specifically, the autoregressive (AR) model is implemented, which is also known as linear predicting coding (LPC). The goal is to model the atrium and understand the function of the atrium, which can reflect on the varying parameters in the SR and AF cases. In this context, The formant of P-waves is modeled and estimated, which is a representation of the atrium activities. In addition, the parameters of the model are mapped into 2-dimension by the zero-pole plots in order to interpret the differences between SR and AF situations. Based on the differences between parameters and formants, a parametric classifier of high interpretability is developed to detect AF. An alternating searching algorithm is proposed to determine the parameters of the classifier.Electrical Engineering | Signals and System
Experimental investigation of residual stress distribution during turning of weak stiffness revolving parts
No full textAre different income sources fungible? The effects of agricultural subsidy and disaster relief on household consumption in China
No full textThis paper uses panel data from a sample of farm households in the northeastern China to examine the non-fungibility of different income sources. The results show the private transfer income has a high and significant impact on household consumption while agricultural subsidy and disaster relief have insignificant impacts. Empirical findings prove that the Behavioral Life Cycle Hypothesis is more practical than the Life Cycle Hypothesis. Moreover, they provide important macro policy implications as for how to stimulate farm consumption and expand domestic demand and encourage economic growth
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Embracing Uncertainty as the New Norm: A Risk-Based Portfolio Approach for Urban Water Investment Planning
No full textProviding secure and reliable water supply service to major urban areas has become a considerable challenge in recent years on a global basis. Rapid population growth, urbanization and development needs put enormous pressure on water resource managers to satisfy the ever-growing demand. Climate change, in addition to the inherent variability in hydrological cycles, adds another layer of deep uncertainty to forecast surface water availability. Many major cities have observed declining reservoir storages during unprecedented droughts. The once-reliable reservoir storage systems can no longer serve its purpose. During extended period of water shortages, urban residents and businesses suffered from mandatory water restrictions, causing large economic and social welfare losses. Facing these challenges, water utilities and governments make large investments in supply augmentation infrastructure, which have long-term consequences that can shape development for decades. However, the increasing complexity of uncertainty suggests that the ability to predict the future is limited; hence, there is a need to shift from the conventional “predict-then-act” planning paradigm. This thesis presents an alternative framework to urban water investment planning, using a portfolio approach.
A generalized risk-based framework for urban water supply-demand planning is proposed, and it is applied to Melbourne, Australia, to demonstrate its utility and usefulness. First of all, water shortage risk is clearly defined in two terms–frequency and severity of water shortages–of a defined planning horizon. Supply-side uncertainty is quantified based on probability distributions of precipitation and runoff to reservoirs. Demand-side uncertainty is modeled by scenarios with different combinations of population growth rate and per capita water usage. Next, the thesis presents an investment decision-making tool to identify cost-effective supply-demand portfolios that minimize water shortage severity while achieving a target level of reliable service. In addition to find the optimal portfolio composition, the model presents sequences of investments, indicating timing of implementation of each chosen measure. Using mixed integer programming, the decision-making tool yields Pareto efficient frontiers for different demand scenarios. The Pareto frontier exhibits trade-offs between cost of a water supply-demand strategy and water shortage risks facing a society in the long run. The trade-offs provide analytical insights on risk attitude towards water supply services, namely (i) what is the acceptable level of water shortage risk for a society, and (ii) how much are customers willing to pay to avoid such a risk. The results indicate that a portfolio which diversity risk of individual supply augmentation and conservation measures is robust when confronting a wide range of plausible climate and demand growth scenarios. Finally, recognizing important roles played by society and government in water-related investment decision-making process, the thesis discusses institutional barriers in adopting and implementing the proposed risk-based framework in practice.
This thesis presents an alternative framework to quantitatively integrate risk in urban water resources management. Under this framework, the portfolio approach is an analytical tool for decision-makers to prioritize investments in supply augmentation infrastructure and implementation of demand management programs. It is the hope of the author that this work provides new insights and necessary tools to water sector professionals in urban water investment planning. The use of risk-based framework and portfolio approach is not limited to any specific city and could find many applications in urban areas where water scarcity and climate risk are pressing issues.Engineering and Applied Sciences - Engineering SciencesWater infrastructure investment; risk-based planning; urban water resources management; supply-demand planning
Author Correction: Effect of recombinant human erythropoietin combined with iron sucrose on postoperative hemoglobin in patients undergoing artificial joint replacement
No full textA novel way to synthesize calcium sulfate whiskers with high aspect ratios from concentrated calcium nitrate solution
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