The evolution of State-Local balance sheets in the United States, 1953–2013

State and local debt in the United States more than doubled as a share of gross domestic product between 1953 and 2007. Using a historical accounting framework, we find that there is no straightforward relationship over time between state and local deficits and debt growth. We find that only 17 percent of the variation in aggregate state–local debt ratios comes from variation in the fiscal balance. This is especially true in the 1980s, the period of most rapid increase in state–local debt ratios. Before 1980, there were small but persistent deficits, but stable debt ratios. In the 1980s, state and local sectors shifted toward budget surpluses but saw rising debt ratios. This is explained by a faster pace of asset accumulation. Our results demonstrate the autonomy of balance sheet variables and suggest that changing debt ratios cannot be explained by real income and expenditure flows.     

热力景观在城市生态规划中的应用

本文在引入城市热力景观这一概念来综合反映城市生态环境的基础上,阐述了一种以城市热力景观为背景对城市进行规划的方法:利用生态廊道的传输作用、切割作用、防护作用,以廊道为纽带,以水、路、风、林等贯通性廊道对城市生态环境进行疏导,使生态效应由线向面扩展,用线网结构沟通,从而形成城市生态的优化机制。     

Combining Sources of Preference Data for Modeling Complex Decision Processes

We review current state-of-the-art practices for combining preference data from multiple sources and discuss future research possibilities. A central theme is that any one data source (e.g., a scanner panel source) is often insufficient to support tests of complex theories of choice and decision making. Hence, analysts may need to embrace a wider variety of data types and measurement tools than traditionally have been considered in applied decision making and choice research. We discuss the viability of preference-stationarity assumptions usually made when pooling data, as well as random-utility theory-based approaches for combining data sources. We also discuss types of models and data sources likely to be required to make inferences about and estimate models that describe choice dynamics. The latter discussion is speculative insofar as the body of literature on this topic is small.     

Market share instability and stock price volatility during the industry life-cycle: the US automobile industry

Market share instability, during certain stages of the industry life-cycle, has become a stylized fact in the industrial organization literature. In the finance literature, volatility in the form of excess volatility, i.e. the much larger volatility of stock prices than dividends (although stock prices should in theory trace the present value of future dividends), has given rise to controversies regarding stock price determination (Campbell and Shiller, 1988; Shiller, 1989). Recent evolutionary models, both theoretical and empirical, have tied the presence of market share instability to industry specific variables, such as specific periods in the industry life-cycle and specific “technological regimes”. The object of the paper is to explore whether there is a relationship between market share instability and stock price volatility and to what degree this relationship is connected to the concept of the industry life-cycle, and hence to industry specific factors. To do so, we explore the relationship in one particular industry, the US automobile industry. Since neither life-cycle nor finance theories attack this problem directly, we use insights from both approaches to build hypotheses which guide the data analysis. The empirical results confirm many of these hypotheses, suggesting that the degree of excess volatility is indeed partly affected by industry specific factors.     

Timing,order and durability of new product advantages with imitation

This research examined the effects of timing, order and the durability of first mover advantages by analyzing the stock market reactions to new product introductions and imitations. The major findings are that both timing and order of moves are important and that rival reactions undermine the durability of first mover advantages. More specifically, (1) early and fast movers achieve greater gains than late and slow movers, and (2) first movers suffer at the time of new product imitations. Copyright © 2000 John Wiley & Sons, Ltd.     

镍基高温合金GH4169试件有限元分析与寿命预测

对光滑薄壁管进行了多轴恒幅比例加载疲劳试验,并运用弹塑性有限元法对该加载条件下的光滑薄壁管进行了分析和计算。结果表明,用有限元法计算的试件应力应变值与试验结果吻合,并用此方法对缺口试件危险点应力应变状态进行了分析。最后,用局部应力应变法预测该试件的疲劳寿命,得到较为理想的预测结果。     

以技术动力学视角看电动汽车的发展前景

在目前能源短缺、环境污染严重、节能减排的巨大压力下,先进的电动汽车技术成为人们关注的热点.基于技术动力学的一般规律,针对电动汽车发展涉及的电池技术发展、充电基础设施及其与电动汽车的协调等问题,对电动汽车作为新生事物具有的学习效应、网络与路径依赖以及其中的不确定性、技术路线与政府的角色等方面进行了分析,可为电动汽车发展战略与政策的制定提供参考.     

Emergence of entrepreneurs following exogenous technological change

This paper explains how, after an exogenous technological change occurs, entrepreneurs displace incumbents who were ex ante capable of exploiting any innovations that resulted from the change. The model initially considers classical economic assumptions in the context of process innovations, and then its robustness to uncertainty, bounded rationality, firm asymmetry, and product innovations are discussed. The model is preliminarily tested against industry trends, using both results from an analysis of the information technology sector and from the literature. The paper does not suffer from the inconsistency of explaining how capable incumbents are displaced by resorting to characterizations of incumbents as incapable due to some inefficiency; the paper models incumbents as efficient yet rationally choosing, in some instances, to be displaced. Copyright © 1999 John Wiley & Sons, Ltd.     

Reciprocal threats in multimarket rivalry: staking out ‘spheres of influence’ in the U.S. airline industry

The paper investigates the outcomes of multimarket competition among U.S. scheduled airlines when the interests and positions of the airlines differ in the mutually contested markets. Asymmetry in territorial interests provides multimarket competitors with footholds in important markets of their rivals, which can be used to deter the behavior of the rivals in other markets. Evidence suggests that airlines use footholds in their rivals’ important markets (particularly in their hubs) to reduce the competitive intensity of those rivals in the airlines’ own important markets (their hubs), and sustain their dominant positions (or spheres of influence) in those markets. Copyright© 1999 John Wiley & Sons, Ltd.     

Learning from processing trade: Firm evidence from China

Processing export plays a significant role in international trade. In this paper, focusing on firm-level dynamics, we show that firms learn from their processing export experience to improve their subsequent ordinary export outcomes. Using transaction-level trade data and firm-level production data, we show that firms’ ordinary export performance, at both extensive and intensive margins, is enhanced by their own processing experience. Firms also export products with improved quality after engaging in processing exports of similar products. Furthermore, we investigate potential channels through which firms learn from processing experience. We find that firms potentially learn from processing experience to enhance production efficiency, to better understand how to improve product appeal to cater to specific markets, and to gain better and easier access to inputs. Moreover, we find that exporters benefit more from processing experience for larger markets with fiercer competition. Similarly, stronger learning effects are also observed when processing experience is associated with products that embody less diffused knowledge and are more differentiated. Also, firms learn more from processing experience when they are more actively engaged in processing imports. Lastly, we verify the economic significance and quantify the importance of these potential channels.