Some Tests of APT Mispricing Using Mimicking Portfolios

Cross-sectional and time-series tests using mimicking portfolios are used to assess the exactness of the APT with(out) a residual market factor. The first factor seems to be sufficient to span the efficient set, whether the model is estimated using (un)conditional variance-covariance matrices that are (un)adjusted for nonsynchronous trading. Although the conditional standard deviations of the mimicking portfolios significantly explain the time-variability of security volatilities, the residuals of the mean equation still exhibit heteroskedasticity. Similar results are obtained for portfolios of CAPM-betaranked securities, and for randomly selected individual securities.     

改进遗传算法在电力系统无功优化中的应用

针对常规遗传算法（GA）的不足,提出了一种改进搜索策略的遗传算法,采取了以下改进措施：在遗传迭代中,根据种群进化过程的个体的适应值大小,对群体进行分级,对级别高的个体进行小范围的搜索,对级别低的个体在大范围内进行搜索,保证群体的多样性的同时,又留住了优良个体。将改进的遗传算法应用于电力系统无功优化,并与常规遗传算法进行了比较,结果表明改进算法在计算速度、收敛性和全局最优搜索能力都有提高。     

The Dynamics of Commoditization in a Vietnamese Uplands Village, 1980–2000

Commodity markets have become key forces transforming upland livelihoods, social relations and landscapes in Vietnam and throughout Southeast Asia. This paper examines the processes of market formation and their effects on local livelihoods and social relations in a village of Vietnam's north-western uplands. The results indicate that villagers' reactions to new opportunities arising from decollectivization and market liberalization wove them into an increasingly intricate 'commodity web'. Differences among households widened as households with an initial advantage accumulated further advantages. Yet the relations governing access to land and product markets also provided a floor of subsistence for the disadvantaged. The findings demonstrate the need to interrogate commodity markets, investigate the practices and relations constituting them, and analyse how they distribute income and risks among the actors involved. The nature of commodity markets, together with the relations governing access to productive resources, influences processes of social differentiation in the uplands.     

提高水分生产率和农业生产能力是我们追求的目标

我长期从事水稻研究工作,特别是对水稻水管理方面做了许多研究.水稻节水灌溉这个项目的研究意义非常大,因为我们知道水资源短缺使许多国家面临挑战,如何解决水危机,是许多专家和相关国际组织共同关注和探讨的问题.     

基于因素分解与总量控制的区域社会经济用水分析

考虑到经济产业结构调整和用水效率控制对社会水循环过程调控的重要性,以江苏沿海开发区域内的盐城市为研究区,根据其社会经济现状与发展计划、水资源开发利用战略与目标、节水型社会建设规划方案等实际情况,采用水资源利用驱动因素分析法和数学规划解析法相结合的手段,建立了纳入驱动因素分解效应量化值的非线性规划模型,计算了2010-2015年研究区基于用水总量控制的社会经济发展规模、产业结构比例及其用水效率的合理方案。最后,根据计算成果,分析了研究区产业结构、用水定额、经济水平与人口规模四个因素对区域用水总量变化的影响。     

Learning Approaches and Outcome‐Based Teaching and Learning: A Case Study in Hong Kong,China

Outcome‐based education is a pedagogical process which focuses on the achievement of certain specified results. Outcome‐based teaching and learning (OBTL), therefore, is concerned with curriculum design and ensuring that the contents, delivery, activities, and assessments are all aligned to help facilitate students to attain specific intended learning outcomes. This study explores whether and how outcome‐based teaching impacts on the learning approaches of one cohort of undergraduate business students at a university in Hong Kong, China to undergo outcome‐based teaching, newly introduced as part of a university‐wide policy to adopt OBTL. The learning approaches of these business students were measured using John Biggs's (1987 Biggs, J. 1987. Student approaches to learning and studying, Melbourne: Australian Council for Educational Research.  [Google Scholar]) Study Process Questionnaire (SPQ) to determine whether these students tended to favor surface learning approaches, deep learning approaches, or achieving learning approaches upon initial entry into the university. Changes in learning approaches were tracked, after a semester's exposure to OBTL, through survey and focus group interview methods. Findings indicated a significant amount of transference between learning approaches deployed by these students, demonstrating a high level of adaptability.     

Modeling farmers’ decisions on tea varieties in Vietnam: a multinomial logit analysis

This article analyzes households’ choice on tea varieties in Vietnam by using a multinomial logit model. The modeling takes into account the issue of unobserved individual heterogeneity and the endogeneity of some explanatory variables (use of chemical and organic fertilizers). The results show that important factors influencing the decision to adopt one type of tea varieties include income, age, household size, farming contract, and use of organic fertilizers, but also membership of professional associations such as the Tea Association and the Farmers Union.     

Cultural distance and cross-border bank linkages

This study investigates the effect of cultural distance on global bank linkages using country-pair data for the period 1990–2013. We followed Schwartz (2006) to measure cultural distance, and employed the number of bank pairs involved in cross-border syndicated lending from the source to target countries as a measure of bank linkages. We found that cultural distance has a negative association with bank linkages. This effect is stronger in countries featuring higher informational asymmetries, as represented by weaker institutions, higher uncertainty, or revolution shocks. Our results hold even when employing alternative measures of bank linkages and cultural distance, and when considering the potential endogeneity of cultural distance.     

Defining personalized concepts for XBRL using iPAD‐drawn fuzzy sets

An efficient and effective analysis of business data requires a better understanding of what the data represents, and to what degree. A human‐like way of accomplishing that without being too detailed yet learning more about data content is to summarize and map the data into concepts familiar to a person performing analysis. Processes of summarization help identify the most essential facts that are embedded in the data. All this is of significant importance for analysis of large amounts of business data required to make good and sound financial decisions. There are two aspects enabling more comprehensive yet easier processing of data: a standardized representation format of financial data; and a human‐friendly way of defining concepts and using them for building personalized models representing processing data. The first of the aspects has been addressed by the eXtensible Business Reporting Language (XBRL)—a standardized format of defining, representing and exchanging corporate and financial information. The second aspect is related to providing individuals with the ability to gain understanding of data content via determining a degree of truth of statements summarizing data based on their own perception of concepts they are looking for. In this paper, we introduce a tablet application—Tablet‐based input of Fuzzy Sets (TiFS)—and demonstrate its usefulness for entering personalized definitions of concepts and terms that enable a quick analysis of financial data. Such analysis means utilization of soft queries and operations of aggregation that extract and summarize the data and present it in a form familiar to analysts. The application allows for defining concepts and terms with ‘finger‐made’ drawings representing a person's perception of concepts. Further, these definitions are used to build summarization statements for exploring XBRL data. They are equipped with ‘drawn’ definitions of linguistic terms (e.g. LARGE, SMALL, FAST) and linguistic quantifiers (e.g. ALL, MOSTLY), and enable summarization of data content from the perspective of a user's interests. The ‘drawn’ linguistic terms and quantifiers represent membership functions of fuzzy sets. Utilization of fuzzy sets allows for performing operations of data summarization in a human‐like way. The application of TiFS illustrates ease of inputting personalized definitions of concepts and their influence on the interpretation of data. This introduces aspects of personalization and adaptation of artificial intelligence systems to perceptions and views of individuals. The proposed application is used to perform a basic analysis of an XBRL document.     

Benchmark Invariancy,Seasonality and APM-Free Portfolio Performance Measures

The Jobson-Korkie (1981) Z score and the positive period weighting (PPW) score of Grinblatt and Titman (1989) are applied to various benchmarks of market and mimicking portfolios to study the benchmark invariancy problem. Significantly different portfolio performance inferences are found for a sample of 146 equity mutual funds depending on the mean-variance efficiency of the portfolio benchmarks (mimicking portfolios versus market indices). Portfolio performance inferences are affected significantly by the number of factors, nonsynchronous trading adjustment, and the sizes of the firms used for factor extraction. The returns of the portfolio benchmarks exhibit significant monthly seasonalities, which, in turn, significantly influence mutual fund performance inferences.