An Application of a Displaced Poisson Process*

Abstract A displaced Poisson process is presented as a reasonable model in describing the stages of certain chronic diseases. Although in some respects the model is an oversimplification of the true picture its feature is that it facilitates the easy estimation of some of the important parameters that arise in this area. Among the quantities estimated are the mean lead time and the distribution function of the time spent in the preclinical state. Properties of some of the estimators are obtained.     

On mixing,compounding, and tail properties of a class of claim number distributions

The mathematical structure underlying a class of discrete claim count distributions is examined in detail. In particular, the mixed Poisson nature of the class is shown to hold fairly generally. Using some ideas involving complete monotonicity, a discussion is provided on the structure of other class members which are well suited for use in aggregate claims analysis. The ideas are then extended to the analysis of the corresponding discrete tail probabilities, which arise in a variety of contexts including the analysis of the stop-loss premium.     

基于概率积分法的顶管施工地表变形预测

为了预测顶管地表变形,分析顶管施工地层损失的原因,将概率积分法应用于顶管地表变形预测,在VC6.0下开发了相应的计算程序,可以给出顶管地表沉降、倾斜、曲率、水平变形、水平移动5种变形,以及绘制顶管地表变形的横断面图、平面等值线图和三维立体图。将该程序应用于广州某顶管工程地表变形预测,与实测数据对比,验证了本文方法和程序的正确性,从而为顶管地表变形预测提供了一种新方法。     

Large deviation principles and loglog laws for observation processes

Let ( X_n, n ≥ 1) be an i.i.d. sequence of positive random variables with distribution function H . Let φ _H := {(n, X_n ), n ≥ 1) be the associated observation process. We view φ h as a measure on E := [0, ∞) ∞ (0, φ] where φ_H (A) is the number of points of φ _H which lie in A . A family ( V_s, s> 0) of transformations is defined on E in such a way that for suitable H the distributions of ( V_sφ_H, S > 0) satisfy a large deviation principle and that a related Strassen-type law of the iterated logarithm also holds. Some consequent large deviation principles and loglog laws are derived for extreme values. Similar results are proved for φ _H replaced by certain planar Poisson processes.     

Prevention and mitigation of epidemics: Biodiversity conservation and confinement policies

This paper presents a first model integrating the relation between biodiversity loss and zoonotic pandemic risks in a general equilibrium dynamic economic set-up. The occurrence of pandemics is modeled as Poissonian leaps in economic variables. The planner can intervene in the economic and epidemiological dynamics in two ways: first (prevention), by deciding to conserve a greater quantity of biodiversity to decrease the probability of a pandemic occurring, and second (mitigation), by reducing the death toll through a lockdown policy, with the collateral effect of affecting negatively labor productivity. The policy is evaluated using a social welfare function embodying society’s risk aversion, aversion to fluctuations, degree of impatience and altruism towards future generations. The model is explicitly solved and the optimal policy described. The dependence of the optimal policy on natural, productivity and preference parameters is discussed. In particular the optimal lockdown is more severe in societies valuing more human life, and the optimal biodiversity conservation is larger for more “forward looking” societies, with a small discount rate and a high degree of altruism towards future generations. Moreover, societies accepting a large welfare loss to mitigate the pandemics are also societies doing a lot of prevention. After calibrating the model with COVID-19 pandemic data we compare the mitigation efforts predicted by the model with those of the recent literature and we study the optimal prevention–mitigation policy mix.     

《复变函数与积分变换》教学改革的探索与实践

根据《复变函数与积分变换》课程特点,结合我校办学思想和人才培养目标,从教学内容,教学方法和教学手段,考核方式等方面进行课程改革,取得了较好的教学效果。     

Testing whether waterfowl hunting benefits increase with greater water deliveries to wetlands

The change in waterfowl hunting benefits due to an increase in water deliveries to the levels required for biologically optimal wildlife refuge management at California's San Joaquin Valley National Wildlife Refuges are estimated with the Travel Cost Method, using both ordinary least squares and Poisson count data estimators. To test whether these increases were statistically significant, the Krinsky and Robb technique was used to find confidence intervals around the consumer surplus point estimates. The increases in consumer surplus were found to be statistically significant in 5 of the 6 refuges based on OLS regression estimates and in all 6 refuges using Poisson count data regression estimates. In addition, a comparison of the marginal value of an acre-foot of water in consumptive recreational use versus agriculture use is made, with the finding that the marginal value of water in waterfowl hunting was greater than the marginal value of water in agriculture for one of the six refuges.     

Impact of organizational innovation on product and process innovation

The purpose of this paper was to test the effect of organizational innovation on product and process innovation (while controlling for endogeneity). Our hypothesis was that organizational innovation should have a significant and positive impact on technical (product or process) innovation. We control for endogeneity by using a Poisson estimator that accommodates a binary endogenous regressor. We test 10 potential instruments using a battery of test criteria and settle on five. All results are presented using the five instruments to avoid expectation bias. In general we find that organizational innovation does impact technical innovation positively. With the 2009 data we find that the mean of the average treatment effect for product innovation is roughly 1.7 times that of process innovation. For the 2009–2012 data we find that the impact on product innovation is roughly 1.5 times that of process innovation. For the 2012 data, we had anomalous results for process innovation, such that organizational innovation reduced the number of process innovations by 2.3 per year. In terms of Canadian government policy, the results lend support to the view that technical innovation is not the only innovation that matters. The right policy mix may encourage firms to experiment with and adopt more organizational innovations to enhance technical innovation.     

International collaboration and innovation: Evidence from a leading Chinese multinational enterprise

This paper investigates the impact of international collaboration and its characteristics on the quality of the innovation of multinational enterprises (MNEs) in emerging markets. Using a unique dataset of 1428 international and comparable domestic collaboration projects over the 2010–2016 period, it finds that while international innovation collaborations are associated with high innovation quality, cultural distance has a negative effect on collaboration outcomes. Moreover, proximity to the focal firm's overseas R&D centres and the size of expenditure budgets play significant moderating roles in overcoming cultural barriers. Based on the RBV and dynamic capabilities theory, we investigate how firms from emerging markets can acquire these two crucial requisites for innovation. The characteristics of partners and intellectual property (IP) arrangements are also found to have a significant impact on the quality of innovations.