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Search Results: 1 - 10 of 140739 matches for " Ying Li "
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Evaluating and Improving the Effectiveness of Vehicle Inspection and Maintenance Programs: A Cost-Benefit Analysis Framework  [PDF]
Ying Li
Journal of Environmental Protection (JEP) , 2017, DOI: 10.4236/jep.2017.812095
Abstract: Motor vehicle inspection and maintenance (I/M) programs are designed to identify high-emitting vehicles and mitigate their impacts on air quality and climate. I/M programs have been traditionally ranked superior among various vehicle emission control measures by the results of cost-benefit analysis, based on the assumption that these programs will achieve the targeted emission reduction outcomes. However, the actual effects of I/M programs may be greatly uncertain and when this uncertainty is taken into account, these programs may become suboptimal. This study develops a new a cost-benefit analysis framework that links various program design consideration, such as program participation rate, identification rate and effective repair rate, to the public health benefits as well as costs of the programs. This framework helps decision makers to investigate minimum implementation requirements that at least ensure the benefits are greater than the costs of implementing the programs in order to improve the overall effectiveness of the I/M programs. To illustrate the applications of the framework, it was applied to a particulate matter oriented I/M program targeting all diesel-fueled vehicles in the city of Bangkok, Thailand, a large metropolitan area that has been suffering from severe ambient PM pollution mainly attributable to its wide use of diesel-fueled vehicles and motorcycles. It was found that the health benefits achieved from the program are sensitive to several key program design elements, including participation rate and problem vehicle identification rate, fraction of effective repairs and illegal operation rate. Other variables, such as the testing cut-points and vehicle population growth rate, only have modest effects on the overall emission reduction and consequent health benefits. Overall, the performance of multiple variables associated with I/M program design needs to be improved simultaneous in order to achieve the targeted benefits of the program.
Feasibility Analysis of Flipped Classroom in Chinese Adult English Training  [PDF]
Ying Li
Open Journal of Social Sciences (JSS) , 2018, DOI: 10.4236/jss.2018.65003
Abstract: Flipped teaching has gained a growing popularity, starting from higher education and coming all the way down the academic pyramid to the primary schooling. Evidence has shown that positive results are produced in improving learning results. However, it remains to be seen whether these developments can be extended to the training outside of traditional academic settings and realize its full potential in adult English class. Therefore, essential features of the flipped classroom, adult English teachers, adult English learners and learning environment in the private language education institutions are presented to analyze the feasibility.
A Comparison of TOEFL iBT and IELTS Reading Tests  [PDF]
Ying Li
Open Journal of Social Sciences (JSS) , 2018, DOI: 10.4236/jss.2018.68023
Abstract: With the increasing popularity among test takers and mounting acceptance from academic institutions, TOEFL iBT and IELTS are regarded and treated as equals due to similar purposes and goals. In depth, they distinguish each other in various aspects. By integrating Bachman’s framework of test method facet and Alderson’s variables of reading nature, this article formulates a comparison framework in an attempt to compare the reading parts of these two tests. The results show they share more similarities in test rubrics and input format and slightly differ from each other in score method and specification of procedures and tasks. However, substantial differences are identified in such areas as the nature of language and characteristics of tasks, which has a significant impact on test takers’ performance because TOEFL iBT reading test is more difficult in terms of readability, text types, topical features and question types, while IELTS more complex in text length and grammatical intricacy.
Literature Analysis of Innovation Diffusion  [PDF]
Ying Li, Mengqing Sui
Technology and Investment (TI) , 2011, DOI: 10.4236/ti.2011.23016
Abstract: The theory of innovation diffusion has become increasingly complex and multifaceted in recent years. It has been used in consumer durables, services, pharmaceutical industry and other industry research. In this paper, we use literature analysis to study the development of innovation diffusion theory, searching related literatures from Elsevier, EBSCO, Emerald, Scopus and ISI databases published between 1990 and 2010. From these literatures, we analyze the number of literatures, journal distribution, core authors, as well as the main research directions. Then, we get many conclusions which are useful for the future research of innovation diffusion.
Competitive Innovation Diffusion in Small-World Network: Agent-Based Modeling and Simulation  [PDF]
Yunfeng Yan, Ying Li
Technology and Investment (TI) , 2012, DOI: 10.4236/ti.2012.33028
Abstract: The main purpose of this paper is to analyze the dynamic process when two competitive innovations diffuse simultaneously in the small world network. To illustrate the micro diffusion process, an agent-based modeling and simulation method is applied. In the agent based model, there are two competitive innovations. Agents make decisions to adopt one of the innovations according to the utility value. The sensitivity of the parameters of the utility function is analyzed. The result indicates that in the early stage and the late stage the advertisement strategy is better; while in the middle stage the word-of-mouth will be better.
Environmental Sound Recognition Using Double-Level Energy Detection  [PDF]
Xiaoxia Zhang, Ying Li
Journal of Signal and Information Processing (JSIP) , 2013, DOI: 10.4236/jsip.2013.43B004
Abstract:

The performance of classic Mel-frequency cepstral coefficients (MFCC) is unsatisfactory in noisy environment with different sound sources from nature. In this paper, a classification approach of the ecological environmental sounds using the double-level energy detection (DED) was presented. The DED was used to detect the existence of the sound signals under noise conditions. In addition, MFCC features from the frames which were detected the presence of the sound signals by DED were extracted. Experimental results show that the proposed technology has better noise immunity than classic MFCC, and also outperforms time-domain energy detection (TED) and frequency-domain energy detection (FED) respectively.

Jumps in High-Frequency Data on the Chinese Stock Market  [PDF]
Ying Li, Tengfei Jiang
Journal of Mathematical Finance (JMF) , 2017, DOI: 10.4236/jmf.2017.72025
Abstract: This study adopts two nonparametric methods, the activity signature function (ASF) and ratio analysis of cojumps, to test jumps in China’s stock market. Jumps in the stock price, stock-index futures, and volatility of China Securities Index (CSI) 300 index are analyzed using data on the continuous main-contract price of the index. The findings are as follows. First, in the long run, the CSI 300 index process is a continuous process exhibiting jumps at all sampling intervals. In the short run, the index becomes a pure-jump process in times of recession while exhibiting the characteristics of a continuous or even semimartingale process in certain intervals. Second, the stock-index futures process is a continuous process with jumps at all sampling intervals and, in the short run, exhibits the characteristics of a pure-jump process every 6 months. Moreover, the volatility process generally exhibits the characteristics of pure-jump processes. Third, the CSI 300 index price process and the continuous main-contract price process of the CSI 300 stock-index futures are significantly and positively related, with jumps occurring with a time lag of less than 5 minutes; by contrast, the volatility and price processes of the index are nonsignificantly related.
Static and Dynamic Structure Characteristics of a Trust Network and Formation of User Trust in an Online Society  [PDF]
Ying Li, Hongduo Cao, Ying Zhang
Social Networking (SN) , 2018, DOI: 10.4236/sn.2018.74016
Abstract:
This study investigated the characteristics and formation of the online social trust network of Epinions.com, a general consumer review site. An analysis of the static structure of this social trust network revealed a high clustering coefficient, short average path length, and power-law degree distribution; it is therefore a small-world and scale-free trust network. The dynamic evolutionary characteristics of the online social network (OSN) were also examined. The results showed that the scale of the network followed a sigmoidal curve; the average degree of the network was nonconstant and changed into a bell-shaped distribution; the density of the network decreased and subsequently stabilized; and user trust diffusion in the network conformed to the Bass model. Finally, the formation of trust within the network was researched at the overall network (macro) and individual user (micro) levels. Compared with their accumulated contribution and reputation, user activeness had a larger effect on trust formation in OSNs, indicating a “diminishing returns” phenomenon. This phenomenon contrasts with the Matthew effect (i.e. , the more reputation a person has, the more likely he or she is to be trusted) in real-world social networks.
Multidimensional Time Series Analysis of Financial Markets Based on the Complex Network Approach  [PDF]
Ying Li, Donghui Yang, Xiaobin Li
Journal of Mathematical Finance (JMF) , 2017, DOI: 10.4236/jmf.2017.73039
Abstract: In this study, a modeling method to analyze multidimensional time series based on complex networks is proposed. The rate of return sequence of the closing price and the trading volume fluctuation sequence of the Shanghai Composite Index, the Shenzhen Component Index, the S & P 500 index, and the Dow Jones Industrial Average are analyzed. The two-dimensional time series is transformed into a complex network. We analyze the spatial distribution characteristics of the network to determine the relationship between volume and price. It is found that the interaction of stock return and volume in China’ stock market is more obvious than that in the American market.
Prospects for gamma measurements at LHCb
Ying Ying Li
Physics , 2009,
Abstract: LHCb is the dedicated B physics experiment at the LHC and is due to start data taking later this year. Its goal is to search for new physics in very rare processes and make precision measurements of CP violation in B decays. The CKM angle gamma plays an important role in flavour physics in the Standard Model. LHCb will exploit the large variety of B hadrons produced by the 14 TeV pp collisions, performing gamma measurements to the precision of a few degrees. Here, we will present a summary of the expected gamma sensitivities LHCb will reach during its first years of data taking, with contributions from several strategies in both tree and loop processes.
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