工程工作站在卡车耐撞性分析中的应用

简要论述了汽车耐撞性解析的基本方程及计算方法。以一轻型卡车为例,结合计算方法讨论了工程工作站(Engineering Workstation)在卡车耐撞性解析中应用的几个问题。介绍了一种适合于工程工作站的接触面设定方法。最后给出了一个数值模拟结果。     

A TWO-STAGE UNRELATED RANDOMISED RESPONSE PROCEDURE

In a sample survey, questions requiring personal or controversial assertions often give rise to resistance. A randomised response procedure can be used to help the researcher gather accurate data in this case. This paper describes a new two-stage unrelated randomised response procedure that combines the use of two randomisation devices (Mangat & Singh, 1990) and an unrelated question (Horwitz et al. 1967). It examines the situation where the respondents are not completely truthful in their answers. The efficiency of this new method is compared with the original one-stage procedure proposed by Horwitz et al. (1967), and guidelines for choosing the values of different parameters for the procedures are provided. Results from an empirical study which examines the efficiency and feasibility of the proposed method are given.     

合成孔径雷达图像质量的评估指标

合成孔径雷达(SAR)是一种具有广泛用途的全天候高分辨力成像雷达。由于微波图像与实际物体的视觉形象大不相同,从而使SAR的图像质量评估体系较其它成像系统更难建立。本文根据星载SAR成像算法研究的需要,从成像角度分析和研究了影响SAR图像质量的主要参数,建立了SAR图像质量评估系统,并给出了初步的测试方法。     

Public Concern About Industrial Hazards

In this paper we propose adopting a noncognitive perspective for the understanding of people's anxiety or, its opposite, feelings of security about living near hazardous industrial facilities. Results of our empirical investigations among residents of a heavily industrialized area indicate that at least four qualitatively different response patterns exist: the Secure, the Accepting, the Defensive, and the Vigilant response. In this order manifest anxiety increases, which increase is shown to be a function of the assessment of the threat, of the opportunities for personal control (specific), and of hope (generalized) to bring about a better environment by one's own action. As an application of the usefulness of this typology we discuss the various explanations for the often-observed male/female difference in anxiety regarding industrial threat.     

The Divergent Meanings of Life Satisfaction: Item Response Modeling of the Satisfaction with Life Scale in Greenland and Norway

Cultural differences in response to the Satisfaction With Life Scale (SWLS) items is investigated. Data were fit to a mixed Rasch model in order to identify latent classes of participants in a combined sample of Norwegians (N = 461) and Greenlanders (N = 180). Initial analyses showed no mean difference in life satisfaction between the two subsamples. After transforming the ordinal raw scores into interval scales while simultaneously controlling for response bias, different results appeared. First, approximately 80% of the participants in the Greenlandic subsample fit a latent class with a large degree of random responding to the SWLS. Second, relative to the Norwegians, more Greenlanders were using extreme categories in responding to the SWLS. After statistically controlling for this tendency, Norwegians were in general more satisfied with their lives than Greenlanders. Third, Greenlanders who belonged to one specific latent class were more satisfied than their Norwegian counterparts. A salient feature of this class was the relative unwillingness of respondents to change the circumstances of their lives if they were given such an opportunity. The above results are a reminder of the care that must be used in analyzing survey data across cultures. The analytical strategy applied in the article offers an improved approach to handling such data.     

Development of a Dose‐Response Model for SARS Coronavirus

In order to develop a dose‐response model for SARS coronavirus (SARS‐CoV), the pooled data sets for infection of transgenic mice susceptible to SARS‐CoV and infection of mice with murine hepatitis virus strain 1, which may be a clinically relevant model of SARS, were fit to beta‐Poisson and exponential models with the maximum likelihood method. The exponential model (k= 4.1 × l0²) could describe the dose‐response relationship of the pooled data sets. The beta‐Poisson model did not provide a statistically significant improvement in fit. With the exponential model, the infectivity of SARS‐CoV was calculated and compared with those of other coronaviruses. The does of SARS‐CoV corresponding to 10% and 50% responses (illness) were estimated at 43 and 280 PFU, respectively. Its estimated infectivity was comparable to that of HCoV‐229E, known as an agent of human common cold, and also similar to those of some animal coronaviruses belonging to the same genetic group. Moreover, the exponential model was applied to the analysis of the epidemiological data of SARS outbreak that occurred at an apartment complex in Hong Kong in 2003. The estimated dose of SARS‐CoV for apartment residents during the outbreak, which was back‐calculated from the reported number of cases, ranged from 16 to 160 PFU/person, depending on the floor. The exponential model developed here is the sole dose‐response model for SARS‐CoV at the present and would enable us to understand the possibility for reemergence of SARS.     

Binary Response Models for Panel Data: Identification and Information

This paper considers a panel data model for predicting a binary outcome. The conditional probability of a positive response is obtained by evaluating a given distribution function (F) at a linear combination of the predictor variables. One of the predictor variables is unobserved. It is a random effect that varies across individuals but is constant over time. The semiparametric aspect is that the conditional distribution of the random effect, given the predictor variables, is unrestricted. This paper has two results. If the support of the observed predictor variables is bounded, then identification is possible only in the logistic case. Even if the support is unbounded, so that (from Manski (1987)) identification holds quite generally, the information bound is zero unless F is logistic. Hence consistent estimation at the standard pn rate is possible only in the logistic case.     

The Bubble Game: An Experimental Study of Speculation

We propose a bubble game that involves sequential trading of an asset commonly known to be valueless. Because no trader is ever sure to be last in the market sequence, the game allows for a bubble at the Nash equilibrium when there is no cap on the maximum price. We run experiments both with and without a price cap. Structural estimation of behavioral game theory models suggests that quantal responses and analogy‐based expectations are important drivers of speculation.     

农户对农业技术采用行为的机理研究

农业技术的推广与运用效果不仅取决于农业技术自身的先进性程度,而且有赖于农业技术的终端采用者对农业技术的认知与行为响应状况。在假定农户对农业技术的预期利润最大化作为行为决策的基础上,分析了预期利润最大化的形成原理及其与农业技术采用决策之间的相互作用机理,探究了农户对农业技术行为决策的差异化路径,并从农户的风险偏好、农业技术制度、农户基本特征因素、资源禀赋要素以及农户心理因素等方面深入考察了农户对农业技术的行为响应机理,构建起农户对农业技术采用行为的分析框架;从而不仅有利于掌握农户对农业技术的行为决策机理,而且对于摸清农业技术推广与运用的基本规律、提高农业技术推广与扩散的效果都具有积极的理论参考价值。     

Inverse Regression in Binary Response LDV Model

Sliced inverse regression, a link-free and distribution-free method, is applied to binary response limited dependent variable models. An inverse regression property of binary response LDV model is found. Based on this property, if the distributions of X _j (j = 1, 2,…, p) satisfy the linearity condition, then β can be estimated up to a positive multiplicative scalar without any assumptions on the distribution of error ε. Moreover, the estimator can be proved to be asymptotically normal based on which testing hypotheses are considered. Simulations results are reported.