On Variational Bayes Estimation and Variational Information Criteria for Linear Regression Models

Variational Bayes (VB) estimation is a fast alternative to Markov Chain Monte Carlo for performing approximate Baesian inference. This procedure can be an efficient and effective means of analyzing large datasets. However, VB estimation is often criticised, typically on empirical grounds, for being unable to produce valid statistical inferences. In this article we refute this criticism for one of the simplest models where Bayesian inference is not analytically tractable, that is, the Bayesian linear model (for a particular choice of priors). We prove that under mild regularity conditions, VB based estimators enjoy some desirable frequentist properties such as consistency and can be used to obtain asymptotically valid standard errors. In addition to these results we introduce two VB information criteria: the variational Akaike information criterion and the variational Bayesian information criterion. We show that variational Akaike information criterion is asymptotically equivalent to the frequentist Akaike information criterion and that the variational Bayesian information criterion is first order equivalent to the Bayesian information criterion in linear regression. These results motivate the potential use of the variational information criteria for more complex models. We support our theoretical results with numerical examples.     

Organizational Silence and Whistle‐Blowing on IT Projects: An Integrated Model*

An individual's reluctance to report bad news about a troubled information technology (IT) project has been suggested as an important contributor to project failure and has been linked to IT project escalation as well. To date, information systems researchers have drawn from the mum effect and whistle‐blowing literature to gain a better understanding of the factors that influence bad news reporting. More recent theoretical work in the area of organizational silence offers a promising new conceptual lens, but remains empirically untested. In this research note, we integrate key elements of Morrison and Milliken's (2000) model of organizational silence, which has never been empirically tested, with the basic whistle‐blowing model adapted from Dozier and Miceli (1985) . Using a role‐playing experiment, we investigate how organizational structures/policies, managerial practices, and degree of demographic dissimilarity between employees and top managers create a climate of silence and how this climate, in turn, affects an individual's willingness to report. Our results show that all three types of factors contribute to a climate of silence, exerting both direct and indirect influence on willingness to report, as hypothesized. The implications of these findings and directions for future research are discussed.     

国际金融资产组合的选择--论短期国际资本流动的成因

资本的本质是追求利润。但是,由于不同国家不同的金融资产存在不同的风险,短期资本寻求的不是收益的最大化,而是收益和风险的最优组合;又由于不同的投资者对待风险的态度存在差异,收益和风险的最优组合取决于投资者承担风险的意愿。因此,短期资本流动是由金融资产的收益、金融资产的风险和投资者对风险的态度决定的。在这个领域,马柯维茨(HarryM.Markowitz)作出了杰出的贡献。但是,马柯维茨主要研究国内证券最优组合的选择。本文对短期国际资本流动进行重新定义以后,把马柯维茨以及后人的研究成果加以概括和发挥并用于解释短期国际资本流动的成因。     

A Time-Lag Analysis of the Relationships Among PISA Scores,Scientific Research Publication,and Economic Performance

Due to the poor performance of US students in international math and science tests, many authors worry that the US lead in science is in jeopardy. A recent study by Chen and Luoh (Soc Indic Res 96: 133–143, 2010) challenged this pessimistic view by delinking test performance and labor force quality. It was found that measures such as researchers per capita or scientific journal articles per capita can better account for economic performance. Because it takes time for education and R&;D to yield returns, this project replicated the preceding study using a time-lag structure. Although the results partly concur with previous findings, it is important to point out that GDP might depend on multiple variables acting together. Instead of solely focusing on reforming STEM education as partly measured by international test scores, improving the R&;D infrastructure and openness in trade could also be crucial to the future of the economy.     

《周易》句读辩正四则

关于《周易》中各卦爻辞的句读,学界争议较大。正确的句读是准确理解《周易》语言的重要保障。结合该书的成书地安阳的方言、上下文语境以及语篇结构考察可知,其《无妄.初九》之"无妄往吉",正确的句读当为:"无妄往,吉。"《泰.九三》之"勿恤其孚于食有福"当断为:"勿恤。其孚于食,有福。"《井.九五》之"井冽寒泉食"当断为:"井冽,寒泉食"。《既济》之"亨小利贞"当断为:"亨,小利贞。"     

道家精神烛照下的《边城》世界

《边城》是一个美丽而忧愁的梦,沈从文在这篇小说中建构了诗意的“湘西世界”。他以传统的道家思想为依托,通过对“水”的解读、自然本色的重视、自然人格的推崇及乡土、家园守望的多元叙述,折射出深厚的道家文化内涵。     

CDIO教育理念下法律人才培养的思考

高等院校法学教育在依法治国、建设法治国家的进程中担负着重要的历史使命。法学本科教育应以培养适应社会需要的实用型法律人才为目标,CDIO教育理念与实践性法律人才的培养目标具有契合性。基于CDIO教育理念进行法律人才培养的研究和思考具有重要的理论和现实意义。     

CDIO教育理念下的法律人才培养方式改革

文章提出了当前法学教育所存在的问题,试图从培养职业道德、优化知识结构和训练实践能力三方面探讨如何引入CDIO教育理念,以改革传统的法学教育教学方法,尽快提高法律人才的质量。     

论隋唐时期的越州都督府

隋唐时期,今绍兴市被称作越州,其治城是浙江地区的军政、经济、交通和文化中心,具有重要的历史地位.南朝迄隋唐,置于今绍兴市的州级政区经历过几度演替,即东扬州--吴州--越州--会稽郡--越州的变化.隋开皇九年始,在越州城(今绍兴)先后建置吴州总管府、越州总管府、越州都督府、浙东观察司和镇东军节度司等地方高层管理机构.开元末年,越府管8州,相当今浙江省的绝大部分.越州城是隋唐时期浙江地区的中心城市.其历史地位表现在:绍宁平原的经济社会快速发展推动其中心城市的出现、越州城是联结内地与海外交通的中枢节点、越州城文化教育事业不断发展、文化名人辈出等方面.     

资产链中的股票可交易过程模型研究

资产链是指在金融创新的推动下,金融资产形态及其价值不断演变和深化而构成的逻辑路径.基于资产链的思想,股票的可交易过程不仅包括可流动过程,还包括可波动过程,时变流动性条件下的可流动过程模型显示可流动价值是股票换手率的函数,其表现与资金的时间价值类似,内在价值不变前提下的可波动过程模型则将可波动价值表示为美式期权,受股票的预期波动率、持有成本和投资者对波动性期权的心理预期时间的共同影响,但与股票的初始价格无关.