基于Logistic模型产业集群演化稳定性研究

依据产业集群的内在关系,产业集群有非正式集群、有组织的集群、创新型集群三个层次或形态,针对不同演化形态我们分别建立了Logistic模型,并对稳定平衡态下企业共生经济效益进行了分析和对比,研究了它们共生的条件和原因。另外产业集群演化除了能够产生稳定平衡的、周期的动态行为外,还可能产生混沌的现象,单一的线性因果关系不能解释其演化规律;同时产业集群演化所具备的初值依赖性也促使演化混沌的可能产生;在集群演化混沌状态下,集群的演化发展方向、模式由集群内部企业间共生性和合作稳定性以及外部环境的影响共同决定。就我国产业集群的发展而言,要有条件有选择地引导产业集群的形成和发展,培育和加强集群内部的共生机制,应本着区域产业集群与区域经济协同发展的原则,选择适应性的产业集群发展战略。     

Infinite Parameter Estimates in Logistic Regression, with Application to Approximate Conditional Inference

This paper discusses recovery of information regarding logistic regression parameters in cases when maximum likelihood estimates of some parameters are infinite. An algorithm for detecting such cases and characterizing the divergence of the parameter estimates is presented. A method for fitting the remaining parameters is also presented . All of these methods rely only on sufficient statistics rather than less aggregated quantities, as required for inference according to the method of Kolassa & Tanner (1994). These results are applied to approximate conditional inference via saddlepoint methods. Specifically, the double saddlepoint method of Skovgaard (1987) is adapted to the case when the solution to the saddlepoint equations exists as a point at infinity     

房地产上市公司财务预警实证研究

房地产业已成为我国重要的支柱产业,因此,建立房地产上市公司财务预警方法对政府、投资商、中介公司和广大消费者都具有重要意义。以主成分分析和逻辑回归分析为基础建立分析模型,并用该模型对2002~2005年沪、深两市45家房地产业上市公司进行实证分析,发现模型对房地产上市公司前两年和前四年的财务预警有较高的可信度。     

国民经济动员中的物流链探讨——伊拉克战争和抗击“非典”活动案例研究

伊拉战争和抗击“非典”的活动启动了国民经济动员工作,尤以“物流”为突出。本文从物流链的角度,分析了这两次国民经济动员活动的异同,为提高国民经济动员能力提供了新的思路。     

The analytic construction of D-optimal designs for the two-variable binary logistic regression model without interaction

Candidate locally D-optimal designs for the binary two-variable logistic model with no interaction, which comprise 3 and 4 support points lying in the first quadrant of the two-dimensional Euclidean space, were introduced by Haines et al. (D-optimal designs for logistic regression in two variables. In: Lopez-Fidalgo J, Rodrigez-Diaz JM, Torsney B, editors. MODA8 – advances in model-oriented designs and analysis. Heidelberg: Physica-Verlag; 2007. p. 91–98). The authors proved algebraically the global D-optimality of the 3-point design for the special case in which the intercept parameter is equal to?1.5434. However for other selected values of the intercept parameter, the global D-optimality of the proposed 3- and 4-point designs was only demonstrated numerically. In this paper, we provide analytical proofs of the D-optimality of these 3- and 4-point designs for all negative and zero intercept parameters of the binary two-variable logistic model with no interaction. The results are extended to the construction of D-optimal designs on a rectangular design space and illustrated by means of two examples of which one is a real example taken from the literature.     

Threshold‐free estimation of functional antibody titers of a group B streptococcus opsonophagocytic killing assay

Opsonophagocytic killing assays (OPKA) are routinely used for the quantification of bactericidal antibodies in blood serum samples. Quantification of the OPKA readout, the titer, provides the basis for the statistical analysis of vaccine clinical trials having functional immune response endpoints. Traditional OPKA titers are defined as the maximum serum dilution yielding a predefined bacterial killing threshold value, and they are estimated by fitting a dose‐response model to the dilution‐killing curve. This paper illustrates a novel definition of titer, the threshold‐free titer, which preserves biological interpretability while not depending on any killing threshold or on a postulated shape of the dose‐response curve. These titers are shown to be more precise than the traditional threshold‐based titers when using simulated and experimental group B streptococcus OPKA experimental data. Also, titer linearity is shown to be not measurable when using threshold‐based titers, whereas it becomes measurable using threshold‐free titers. The biological interpretability and operational characteristics demonstrated here indicate that threshold‐free titers are an appropriate tool for the routine analysis of OPKA data. Copyright © 2015 John Wiley & Sons, Ltd.     

Bayesian adaptive dose‐escalation procedures for binary and continuous responses utilizing a gain function

One of the main aims of early phase clinical trials is to identify a safe dose with an indication of therapeutic benefit to administer to subjects in further studies. Ideally therefore, dose‐limiting events (DLEs) and responses indicative of efficacy should be considered in the dose‐escalation procedure. Several methods have been suggested for incorporating both DLEs and efficacy responses in early phase dose‐escalation trials. In this paper, we describe and evaluate a Bayesian adaptive approach based on one binary response (occurrence of a DLE) and one continuous response (a measure of potential efficacy) per subject. A logistic regression and a linear log‐log relationship are used respectively to model the binary DLEs and the continuous efficacy responses. A gain function concerning both the DLEs and efficacy responses is used to determine the dose to administer to the next cohort of subjects. Stopping rules are proposed to enable efficient decision making. Simulation results shows that our approach performs better than taking account of DLE responses alone. To assess the robustness of the approach, scenarios where the efficacy responses of subjects are generated from an E _max model, but modelled by the linear log–log model are also considered. This evaluation shows that the simpler log–log model leads to robust recommendations even under this model showing that it is a useful approximation to the difficulty in estimating E _max model. Additionally, we find comparable performance to alternative approaches using efficacy and safety for dose‐finding. Copyright © 2015 John Wiley & Sons, Ltd.     

"言意之辨"与宋明理学

以"言意之辨"的方法,重新解释儒家经典,建构"性与天道合一"的本体论的形而上学体系,弘扬儒学精神,是宋明理学家之所以能够实现综合创新的深层原因,具体体现在三个方面一是"得意忘言"经典解释方法;二是"圣人体无"的本体直觉方法;三是"辨名析理"的逻辑建构方法.     

Ethnicity as a risk indicator for musculoskeletal disease, long consultation times and care utilization A prospective visitor study of 438 consecutive adult consultations of a primary health care centre

This article shows the influence of ethnicity (people born outside Sweden and in Sweden) and social class (socioeconomic class) on the distribution of diagnoses, consultation time and health care utilization in primary health care controlled for sex, age, marital status and educational level. The study was designed as a prospective primary health care utilization study during 7 consecutive weeks. Of a total of 439 adults who lived in the residential area, 290 were born in Sweden and 149 were born elsewhere. The data were analysed unmatched with logistic regression and Poisson regression in main effect models. People born outside Sweden received significantly more diagnoses per consultation than people born in Sweden. The strongest independent risk indicator for musculoskeletal disease was being born outside Sweden, with an estimated odds ratio (OR) of 5.01, 95% confidence interval (CI) = 2.70–8.72. Age over 44 was associated with increased odds for musculoskeletal disease. Respiratory disease, as an indicator of less serious disease, were significantly less common among people born outside Sweden (OR = 0.53, 95% CI = 0.33–0.87). Being born outside Sweden was a risk indicator for consultations longer than 30 minutes (OR = 3.03, 95% CI=1.18–7.43). There were no differences between people born in Sweden and those born elsewhere in health and utilization. Social class was not associated with any of the dependent variables.