Differences and derivatives in kernel estimation

Estimators of derivatives of a density function based on differences of the empirical distribution function (Maltz 1974) are identified as derivatives of kernel density estimators using particular kernel functions. Properties of this family of kernels are investigated.     

Assessing the importance of urban tourism: Conceptual and measurement issues

Urban tourism has not received extensive recognition in tourism research, policy and planning yet its current and potential market is great. Improving the understanding of the importance of urban tourism requires the development of analysis and research methodologies related specifically to this sector. Based on Calgary, Canada, this article develops a model of urban tourism systems and ways in which potential and needs may be identified.     

正确处理城乡一体化进程中的五个基本关系--以浙江嘉兴为例

统筹城乡发展,推进城乡一体化,已经成为十六大以来发达地区的一项重大的发展战略。该文以浙江嘉兴为例,从理论层面对城乡一体化过程中的五个基本关系进行了初步探讨。     

Optimal Self-Reporting Schemes with Multiple Stages and Option Values

We consider a model of optimal law enforcement where sanctions can be reduced for self-reporting individuals. We distinguish between a first self-reporting stage before the case is investigated and a second one where the criminal is detected, but not yet convicted. Since we assume that violators have private information in both stages, fine reductions for self-reporting individuals lead ceteris paribus to a higher violation frequency. Nevertheless, we show that fine reductions should be granted in both stages. We characterize the connection between the two fine reductions in the optimal policy and relate our results to self-reporting schemes observed in reality.     

Optimal Income Taxation and the Ability Distribution: Implications for Migration Equilibria

As recently argued by Diamond (1998), one of the key factors explaining the progressivity of an optimal non-linear income tax is the distribution of productivity among workers. Migration is one source of changes in the productivity distribution. How changes in the populations ability distribution affect optimal income tax schedules has received little attention. Changing the distribution generally affects both the objective function and the government budget constraint. We first consider the comparative statics of the fraction of highly-skilled workers with maximin and maximax welfare functions (so that only the second effect is present) and a quasi-linear utility function. We also present some results for a utilitarian social welfare function.We then study the interaction between mobility and redistributive taxation. We consider mobility by either the skilled or unskilled population under majority voting where governments take the population as fixed. If individuals choose to relocate independently, having identical ability distributions is always a stable equilibrium when the unskilled are the mobile group. However, this is not always the case when the skilled are mobile. If groups of individuals can choose where to locate, having identical ability distributions across regions is only an equilibrium when the mobile type has an overall majority.     

Loan Portfolio Swaps and Optimal Lending

Theories on loan portfolio swap hedging are based on a portfolio-choice approach. This paper presents an alternative: a firm-theoretic model for bank behavior with loan portfolio swaps. Our paper derives the optimal loan rate and rate-taking loan amount of the banks portfolio, and relates them to the market loan rate, counterparty loan rate, swap default risk, capital-to-deposits ratio, and deposit insurance. We find that in the bilateral default risk approach, the comparative static results are generated by four factors: the banks risk magnitude about the equity market value, loan composition in the swap contract, the substitution effect in the loan portfolio, and the income effect from the swap transaction. The results imply that changes in the payoff asymmetry in the event of swap default and the banks regulatory parameters have a direct effect on the banks loan portfolio for lending and swap transactions.We would like to thank two anonymous referees for helpful comments and advice.     

Formal statistics and informal data analysis, or why laziness should be discouraged

The paper gives a personal view on how empirical research and subsequent data analysis and reporting should ideally proceed. Although the introduction concedes that practical limitations and imperfect knowledge usually impose restrictions on our possibilities to approximate this ideal situation, it is argued that investigators and statistical consultants should make a strong effort to come close to it. At the stages of design, analysis, and reporting, this requires careful consideration of the selection of the units of analysis, the choice of variables to be included, their measurement process, and the extent to which relevant assumptions are fulfilled. In so far as exploratory data analysis techniques offer the suggestion that they can produce results without such careful consideration, their use should be discouraged unless they are followed by a confirmatory analysis in which the claims of generalizability are better substantiated. Some protest is raised against the idea that the data themselves have a clear structure lying ready to be unveiled by the investigator by means of some numerical or spatial representation, which would permit to draw general conclusions.     

Spatially explicit micro-level modelling of land use change at the rural–urban interface

This paper describes micro‐economic models of land use change applicable to the rural‐urban interface in the US. Use of a spatially explicit micro‐level modelling approach permits the analysis of regional patterns of land use as the aggregate outcomes of many, disparate individual land use decisions distributed across space. In contrast to the models featured by Nelson and Geoghegan, we focus on models that require spatially articulated data on parcel‐level land use changes through time. In characterising the spatially disaggregated models, we highlight issues uniquely related to the management and generation of spatial data and the estimation of micro‐level spatial models.     

中国农村金融发展对城乡收入差距影响的实证分析

从农村金融自身的发展出发,在界定农村金融发展涵义的基础上,设计相应的指标,从规模、效率及结构三个方面来衡量农村金融发展。利用VAR模型对农村金融发展和城乡收入差距之间的长期均衡和短期波动关系进行的实证分析表明:农村金融发展相对规模的扩大拉大了城乡收入差距,农村金融中介效率的提高和非正规金融规模的扩大缩小了城乡收入差距。