神经网络与四阶段预测法在铁路运量预测中的组合应用研究

利用神经网络与四阶段预测法组合构造出新的交通量预测模型,以胶济铁路提速改造为例,就构造的客运量预测模型进行了应用研究。其中以平均增长率法计算客流量的交通分布;以重力模型法计算诱发客流;依据运输阻力构建的分担率模型计算转移客流;在计算诱发客流时考虑了时间价值。     

Determinants and economic consequences of cash flow restatements

The FASB, PCAOB, SEC, and AICPA have all acknowledged that the accounting field needs to revisit the statement of cash flows (SCF). While the overall number of restatements has held steady over the past five years, the percentage of cash flow restatements (CFRs) has risen from 8.7% of all restatements in 2009 to 20.2% of all restatements in 2014. We examine the determinants of CFRs, investors’ differential beliefs about CFRs, and the information content of CFRs by focusing on abnormal trading volume and price reactions to CFRs. We then examine whether the guidance the SEC/AICPA published in early 2006 changed the information content of CFRs. Finally, since the proper classification within the SCF is a current regulatory issue, we examine whether classification shifting within the SCFs impacts the market. The market finds CFRs to be informative with some investor disagreement as shown by higher abnormal trading volume. We also find an incremental volume reaction to changes in operating cash flows after the SEC allowance period. While the market responds negatively to CFRs, we find that the market does not differentiate between whether classification shifting occurs or does not occur with the CFR. This study has implications for policymakers, auditors, and investors since it is one of the first to examine the capital market consequences of CFRs.     

Are Economically Significant Stock Returns and Trading Volumes Driven by Firm‐specific News Releases?

This paper explores whether firm‐specific information events drive economically relevant positive and negative stock price changes and trading volume and, if so, the nature of such information. We find that no less than 65% of significant price changes and trading volume movements in our sample of FTSE 350 companies can be readily explained by public domain information contradicting the thesis that corporate news is not a primary driver, and that share price changes and trading volume activity are driven by factors unrelated to information flows per se. In addition, we find that a parsimonious set of news categories represent the key drivers. Sell‐side analyst stock recommendations and earnings forecast revisions as a class, unaccompanied by other news releases, dominate all other news categories in terms of significant market reaction. However, taking into account the relative magnitude of market response to different news releases, firms' formal accounting disclosures dominate within this domain. As such, we conclude these are not fully anticipated by apparently more timely market disclosures, and that the existence of news services and the activities of the sell‐side analyst are not substitutes for a firm's interim and preliminary results.     

对外直接投资与国际经济合作的宏观动力与惯性假说及在中国的检验

一国对外直接投资与国际经济合作的动力来自于一国的人均GDP与宏观金融环境(用保险密度来简化与量化),一国对外直接投资与国际经济合作的惯性来自于一国对外直接投资量与国际经济合作完成额的滞后期的值与对滞后期变量敏感度系数的大小。本文使用中国1991年至2003年的数据,对对外投资与国际经济合作的宏观动力与惯性假说做了经验检验,该组数据很好地证明了对外投资与国际经济合作的宏观动力与惯性假说。     

An Empirical Analysis of the Effects of Online Trading on Stock Price and Trading Volume Reactions to Earnings Announcements*

This study provides evidence regarding the effects of online trading on stock price and trading volume reactions to quarterly earnings announcements. We test for differences in stock price and volume reactions to quarterly earnings announcements between a period with a significant amount of online trading (1996‐99) and a period without online trading (1992‐95). We conjecture that online trading has increased the proportion of naive investors in the market. We predict that this will result in (1) a decrease in the average precision of investor information prior to earnings announcements leading to higher earnings response coefficients (ERCs), (2) an increase in differential interpretation of earnings leading to higher trading volume reactions that are unrelated to price change, and (3) a decrease in differential prior precision leading to a decrease in the association between trading volume and absolute price change. We find evidence consistent with all three predictions. Our findings are relevant for assessing the validity of concerns about online trading expressed by regulators and the validity of theoretical models of trade with asymmetrically informed investors.     

General equilibrium analysis of the Eaton-Kortum model of international trade

We study a variation of the Eaton-Kortum model, a competitive, constant-returns-to-scale multicountry Ricardian model of trade. We establish existence and uniqueness of an equilibrium with balanced trade where each country imposes an import tariff. We analyze the determinants of the cross-country distribution of trade volumes, such as size, tariffs and distance, and compare a calibrated version of the model with data for the largest 60 economies. We use the calibrated model to estimate the gains of a world-wide trade elimination of tariffs, using the theory to explain the magnitude of the gains as well as the differential effect arising from cross-country differences in pre-liberalization tariff levels and country size.     

The U.S. Share of Trading Volume in Cross‐Listings: Evidence from Canadian Stocks

I analyze the firm‐specific determinants of the U.S. share of trading volume for 126 U.S.‐listed Canadian firms. I find that the U.S. share of volume is directly related to the mass of informed and liquidity traders in the United States relative to Canada, as proxied by relative analyst following, relative duration of listing, and the U.S. share of sales. Evidence also supports the market liquidity argument that the market with lower spreads and greater depths has greater volume. Finally, the U.S. share is directly related to the relative sensitivity of the stock's value to information in the United States.     

Mutual Fund＇s Behavior on Stock Liquidity： Empirical Results from Chinese Security Market

This paper studies the relationship between fund investment and market liquidity by using Chinese security market data. The results show that, among several measures of market liquidity, the indexes based on volume, such as turnover and market depth, have a deeper impact on fund investment decision. Furthermore, the relationship between security liquidity and fund investment varies when market status is taken into account. On the other hand, fund investments have a negative effect on security liquidity measured by market width, while have a positive effect on other liquidity measures. The authors attribute the results to herding behavior of fund investment.     

Can freeway traffic volume information facilitate urban accessibility assessment?: Case study of the city of St. Louis

In urban contexts, accessibility measures are often utilized to represent the interactions among land use, transport and people’s trips to services and other facilities. Accessibility is generally evaluated using conventional traffic measures such as travel time and distance, but traffic volume, which is a product of the travel trips induced by people’s needs, may also be positively related to accessibility. This study tests the hypothesis “can freeway traffic volume information facilitate urban accessibility assessment?” Traffic volume based accessibility models are proposed to investigate this relationship and test the hypothesis. The results indicate that the answer to this question is a qualified “yes”, as there is a statistically significant relationship between traffic volume differences and accessibility. The coefficients of the models can potentially be used as a reference to guide the urban planning process. The limitations of the proposed models can be addressed by deploying Intelligent Transportation Systems (ITS) traffic sensors on ramps and arterial roadways.     

我国民航客运量影响因素分析

为了准确评估民航客运量与其影响因素之间的关系并提高预测精度,以1995-2014年我国民航客运量的统计数据为基础,通过主成分分析法选取出能反映原始指标96.532%信息量的1个主成分,建立了其与民航客运量之间的回归模型,并对回归模型进行了解释和检验。检验结果表明,主成分回归模型有较高的预测精度,预测结果较为准确。