The effects of social heterogeneity on travel patterns: A replication study

This paper examines differences between the U.S. and Australian urban landscape in terms of the relationship between urban structure and the effectiveness of public transportation. A replication study is undertaken that tests the validated hypothesis from a U.S. study that urban travel corridor social heterogeneity reduces patronage of public transportation because of resident concerns with social composition of passengers and effects on the travel privacy dimension. A causal model is identified for the city of Sydney that specifies enogenous and endogenous variables, as per the U.S. study, which affect bus and rail use. Results do not lead to the acceptance of the hypothesized relationship. The presence of social heterogeneity in Sydney travel corridors does not deter residents within the study corridors from using the bus or train for the journey to work, nor do they appear to affect longer term decisions on car ownership. Bus patronage was shown to be dependent on social heterogeneity factors while rail use was associated with car owning households. These results highlight differences in urban spatial structure and travel patterns between Sydney and cities in the U.S. study, and suggest differential effects of changes in urban spatial structure and policy responses.     

一种汽车零部件批次管理装配信息精确追溯过程研究

汽车零部件产品追溯过程是实现缺陷汽车召回的关键,如何实现汽车产品批次精确追溯是汽车制造企业的一个难题,追溯方法的选择直接导致缺陷汽车召回批次和数量是否正确。以物流过程中的零件批次信息为源头来控制汽车装配时追溯信息、实现精确追溯是一种可行的方案,为汽车制造厂进行汽车零部件产品精确追溯提供一种思路。     

The impact of alternative transportation systems on urban structure

This paper extends a recent von Thünen-type model of urban structure by Mills to include two competing forms of transportation, and then compares simulated representative American and European cities with respect to size, density, and land rents. Assuming consumers minimize costs in choosing between competing travel modes, the 19-equation model demonstrates that land rent differentials are diminished by adding an alternative travel mode, and that transport capacity is far more important than fare structures in determining transit patterns and land use. American urban structure appears to resemble European urban patterns as transportation modes proliferate.     

Happiness sentiments and the prediction of cross-border country exchange-traded fund returns

This research examines whether social media (Twitter) happiness sentiment and country-level happiness sentiment indices predict cross-border ETF returns. To account for complicated associations between happiness sentiment and ETF returns, we use a quantile regression approach and find that Twitter and trading market (U.S.) happiness sentiments are strong predictors of future ETF returns, for which both have far greater predictive power than those of their home countries. Home country happiness indices exhibit asymmetric impacts across quantiles, suggesting the importance of trading country (U.S.) and Twitter happiness sentiments. Higher U.S. and home countries’ freedom to make life choices, absence of corruption perception, and confidence in national government precede higher ETF returns, while U.S. GDP, social support, health life expectancy, positive affect, and negative affect precede lower (abnormal) returns. We find that higher return quantile country ETFs provide a safe haven for U.S. investors during a U.S. bear market.     

Factors affecting delinquency of household credit in the U.S.: Does consumer sentiment play a role?

In this study, we provide both theoretical and empirical evidence on the determinants of household loan delinquency for home ownership, credit card and auto loans for the U.S. states in a panel framework over a period from 2003 through 2017. In particular, we examine the impact of consumer sentiments on loan delinquency rates. We show that improved current consumer sentiment significantly induce lower mortgage, credit card and automobile loan defaults in the American states subdivided into four different regions. We also find that the higher overall and expected consumer sentiment raise loan delinquencies. Implicit in this finding is the apparently excessive and inappropriate expansion of loans in the U.S. economy in the face of consumers’ optimism, which in turn, provides an intuitive understanding of the circumstances that could precede a depression or outbreak of anomalies in the financial sector. Our general findings further exhibit significant positive effect of unemployment rate and mostly adverse effect of per capita income on mortgage and automobile loan delinquency rates. The results provide some compelling evidence with regard to the effect of consumer confidence on household credit delinquency rates across various states in the U.S. and are robust to alternative measures of income and mortgage rates.     

Canadian and American Reactions to Drug and Alcohol Testing Programs in the Workplace

We investigated U.S. and Canadian reactions to workplace drug and alcohol testing programs. Canadian truck drivers (n = 183) deemed drug and alcohol testing policies less fair, and were less accepting of these policies, than their American counterparts (n = 153). We also compared the perspectives of recipients versus third-party observers with regard to their reactions to a drug testing program. Unlike the pattern observed among American observers, the responses by Canadian observers were highly similar to those of the recipients. Canadian observers were more inclined to file a formal protest regarding the implementation of a drug and alcohol testing program than were U.S. observers. The results also showed that procedural and interactional justice principles contributed to the program's fairness, acceptance, and lower levels of protest intentions in both Canada and the United States. We propose that scholars and practitioners can gain a better understanding of multinational reactions to drug and alcohol testing by considering not only cultural but also historical, social, political, and other environmental factors that can shape reactions to personnel practices.     

The federal role in commercial technology development

Technology and science are linked in many ways, sometimes tightly, sometimes loosely, but development of new technologies is a fundamentally different activity from scientific research. The U.S. Government, therefore, cannot assume that expenditures for scientific research will automatically translate into the commercial products and processes vital for an internationally competitive economy. Nor can it assume that expenditures on military R&D will contribute broadly to the civilian technology base. If governments wish to support commercial technology development, they must do more than support research.Many American companies, for example, could benefit from programs aimed at the development of generic technologies with broad commercial relevance. Examples include: applied research in microelectronic devices; combustion processes and automobile safety; disciplines such as engineering design; the science base for manufacturing; common technical concerns such as lubrication and wear or structural integrity. They could also benefit from improved mechanisms for the diffusion of such technologies domestically. To fill R&D gaps on both a technology-specific and an industry-specific basis, the existing system — small in scale and largely experimental — of government-supported centers for generic and cooperative R&D could be broadened and strengthened. The U.S. Government could also provide partial support for technology extension services run by State Governments.     

Integration of technical and value issues in air quality policy formation: A case study

This paper deals with the problem of air quality policy making in urban areas where the automobile is the major source of air pollution. A quantitative method for integrating technical and social value issues is outlined and applied to air quality policy formation in Denver, Colorado. The implications of this study for quantitative analysis in policy analysis in general are discussed.The study centers on decisions to be made now for managing the future air quality in the Denver metropolitan region. At the time of the study Denver was in violation of the National Ambient Air Quality Standards for two gaseous pollutants—carbon monoxide and ozone. Three elements of the study are described—structural analysis, quantitative analysis and contextual analysis.The conclusions of the study are: (1) Under 1977 Clean Air Act standards, strategies intended to reduce emissions from automobiles will assure attainment of ambient standards in Denver by approx. 1990. The impacts of these strategies upon the valued dimensions of health effects, cost and lifestyle appear acceptable. The acceptability of adding regulations to accomplish an earlier date of attainment, such as transportation controls, could not be resolved. (2) If federal emissions standards are relaxed, Denver cannot meet ambient standards without making difficult tradeoffs among health effects, economic factors, and citizens' mobility and convenience. (3) Continued increase in the use of diesel automobiles will substantially worsen Denver's “brown cloud” problem. Our analysis also indicates that a “do nothing” option was not acceptable. The choice of a strategy for reducing particulates from diesels involves tradeoffs among health, haze and cost.     

金融企业在金融危机中的风险规避

美国次贷风波爆发以来,无论从全球资本市场的波动还是美国实体经济的变化来看,次贷之祸造成的危害在美国乃至全球范围内都不容小觑。如果仅从中国金融机构持有次贷相关资产的角度来看,中国金融机构在这场危机中遭受了损失,但风险尚在控制范围之内,影响并不算大。也就是说,始发于2007年的这次金融危机对中国金融企业的影响是启示大于损失。     

基于汽车电控技术发展的现代汽车维修方法

随着人民生活水平的提升,对汽车需求增加,推动了汽车工业的快速发展,而汽车工业在发展过程中,对汽车电控发动机系统故障提升了很多检修技术。在实际工作过程中,若发生技术问题,需要尽快解决有关故障,减少车祸的发生,这样才能保护车内人员的人身安全,对于汽车的安全行驶、汽车工业长远发展有着重要影响。     

关于旅游企业发展电子商务的相关思考

旅游业为旅游者提供食、住、行、游、购、娱等多种服务,是世界上发展潜力最大的产业之一,具有极强的综合性。电子商务作为一种新型的商务方式在近年来发展迅速,其体现的开放性、低成本和高效率等特征,使其超越了作为一种新的经济形式所具有的价值,对整个现代经济生活产生巨大而深远的影响。而旅游业和电子商务则存在着一种天然的适应性,两者之间互相吸引、紧密结合。本文主要讨论发展电子商务能够为我国旅游企业带来的竞争优势以及在发展过程中存在问题和障碍并提出对策。     

The Latin Melting Pot Is Boiling Over

A bstract . During the 1970s no area contributed more immigrants to the United States, both legal and illegal, than Latin America. The Latin American population in the U.S. has become the country's fastest growing large minority and unless economic conditions in Latin America improve for its poorer population, these people will continue to enter the U.S. in large numbers. The chaotic social situation in the country's Latin ghettos highlights a grave national problem. A. J. Jaffe, R. M. Cullen and T. D. Boswell of the Research Institute for the Study of Man completed a study of this immigration which deserves far greater attention than it has received. They found that cultural convergence of Latins with the non-Latin White population varied by subgroup, and was heavily dependent upon the volume of immigration of a particular subgroup and the degree of their concentration in this country.     

Modeling frailty-correlated defaults using many macroeconomic covariates

We propose a novel time series panel data framework for estimating and forecasting time-varying corporate default rates subject to observed and unobserved risk factors. In an empirical application for a U.S. dataset, we find a large and significant role for a dynamic frailty component even after controlling for more than 80% of the variation in more than 100 macro-financial covariates and other standard risk factors. We emphasize the need for a latent component to prevent a downward bias in estimated default rate volatility and in estimated probabilities of extreme default losses on portfolios of U.S. debt. The latent factor does not substitute for a single omitted macroeconomic variable. We argue that it captures different omitted effects at different times. We also provide empirical evidence that default and business cycle conditions partly depend on different processes. In an out-of-sample forecasting study for point-in-time default probabilities, we obtain mean absolute error reductions of more than forty percent when compared to models with observed risk factors only. The forecasts are relatively more accurate when default conditions diverge from aggregate macroeconomic conditions.     

Elderly activity patterns and demand for transportation in a small city setting2

Although elderly in a small city setting leave their homes for approximately the same purposes and at the same frequency as elderly in metropolitan settings, they are much more dependent on the automobile. A higher proportion of the elderly in a small city drive, but driving status did not have a significant impact on frequency of travel or the spatial extent of travel. Health status was not an important factor when other variables were taken into account, but the older elderly did take fewer trips than the younger elderly. Income, sex and residential location had modest impacts on activity patterns, but the use of a well-established Dial-a-Ride system was minimal. Variation in activity patterns among the elderly in a small city suggested continuity of behavior, a modest decline with age and a strong preference for automobile travel or walking from conveniently located housing complexes.     

A canonical quality of life model

A five equation model was developed which related measurements of quality of life (QOL) to policy variables and to economic and social characteristics. The model was used to i) determine the jointness, or interdependency, of components of QOL, ii) demonstrate the usefulness of canonical correlation for measuring the marginal products of determinants of QOL, and iii) construct QOL indexes of social indicators. The model's parameters were estimated from state data for the U.S.A. Among the determinants of QOL educational attainment, investments in transportation facilities, region size and urbanization were most important. Expenditures on higher education, health care, and law enforcement had very little effect on socio-economic well being. Most of the differences in QOL between states were due to economic factors.     

Health, Government, and Irving Fisher

A bstract    This paper provides a few historical notes on government involvement in health, followed by a summary of the theoretical arguments that economists offer in its support. Irving Fisher's views and recommendations about health are examined in the light of today's perceptions concerning health, health economics, and health policy. The wide variety of roles that the U.S. and other governments currently play in health is reviewed, and the ability of economics to explain these roles is assessed. The consequences of government involvement for the health of populations, for expenditures on health care, and for political and social stability are examined. The paper concludes with an overview of new worldwide trends in health policy and some probable explanations for these trends.     

报废汽车回收体系结构模型研究

报废汽车的回收重用一方面是＂生产者责任延伸制＂在汽车行业贯彻实施的结果,另一方面来源于再制造环节中蕴藏的丰厚利润的诱导.目前我国回收利用报废汽车的方式比较落后,主要是对原材料进行重用.本文构建了一个由汽车制造商牵头纽建,以功能多样化的回收中心作为中心处理单元的报废汽车回收体系结构模型,以期实现更高层次的回收重用.     

Immigration, Labor Market Mobility, and the Earnings of Native-Born Workers

A bstract .   This article seeks to improve on previous estimates of the impact of immigration on native wages by using an occupational segmentation approach that directly controls for regional migration and other shifts in the native-born U.S. labor supply. The U.S. labor market is segmented by occupation in order to determine which, if any, native workers tend to be vulnerable to increased immigrant competition for jobs. The results suggest that native-born workers in the primary sector are the main beneficiaries of increased immigration, while native-born Hispanic females in the secondary sector are the most susceptible to downward wage pressures.     

A comment on gasoline prices and urban structure

The effect of higher gasoline prices on urban concentration and aggregate work travel is investigated with a simple closed-city general equilibrium model used by Robson and Scheffman. Their approximate solution is shown to be invalid at reasonable parameter values; for the case of a Cobb-Douglas utility function, numerical solution indicates a long-run reduction in average trip length of 1.4% to 2.9% from an increase in transportation cost of 0.5 cents per mile. It is noted that this is still much larger than estimates obtained by other means.     

Bi-objective decision support system for routing and scheduling of hazardous materials

This paper presents a Pareto-based bi-objective optimization of hazardous materials vehicle routing and scheduling problem with time windows and shows its application to a realistic hazardous material logistics instance. A meta-heuristic solution algorithm is also proposed, which returns a set of routing solutions that approximate the frontier of the Pareto optimal solutions based on total scheduled travel time and total risk of whole transportation process. It works in a single-step fashion simultaneously constructing the vehicle route and selecting the optimal paths connecting the routed locations from a set of non-dominated paths obtained in terms of travel time and risk value.