行政、资本与乡土社会:农业经营模式的形塑机制——基于宁夏南部地区蔬菜产业发展的思考

通过对宁夏南部地区蔬菜产业中规模化、资本化农业经营模式建立过程的分析,发现行政、资本与乡土社会是形塑农业经营模式的三个基本因素。具体而言,政府投入的资源和开展的基础性工作,体现了行政力量在新型农业经营模式形成过程中所发挥的引导和保障作用。而在农业高度市场化的情况下,新型的规模化、资本化农业经营模式的建立和发展又离不开资本自身的经营管理能力。也就是说,资本必须通过对劳动力的有效管理生产出符合市场要求的农产品,才能确保新型农业经营模式的成功。而新型农业经营模式能否立足,还取决于资本能否处理好自身与乡土社会的关系,因为后者是新型农业经营模式立足的“社会基础”。基于此,可以认为,行政、资本和乡土社会三个因素及其相互间的关系形塑了我国农业的经营模式及未来的发展形态。     

国家治理中的第三次分配:美国镜鉴与中国道路

第三次分配在中国推动共同富裕迈入新阶段的当下扮演着重要角色。基于国家社会关系视角,将第三次分配划分为强政府大社会、弱政府大社会、强政府小社会、弱政府小社会4种实践模式。美国第三次分配建构起了弱政府大社会实践模式,以社会主导、政府监管、政治中立为主要特征。工具理性是美国第三次分配的成功经验,形成了文化、组织、制度及技术“四位一体”的逻辑理路。隐藏在工具理性外衣下的阶级理性是美国第三次分配的失败教训,在阶级理性思维影响下,社会“私”的方面被放大,形成了以捐赠者为中心的家长制作风。中国第三次分配是先富带动后富、助推共同富裕的实现方式,它深嵌到中国式现代化进程中。中国第三次分配不能照搬美国模式,需要在充分吸收工具理性和摒弃阶级理性的经验教训基础上,塑造强政府大社会模式,将中国文化要素融入制度体系,增强第三次分配主体规范性,加大第三次分配激励力度,完善第三次分配监管体系,持续并高度关注贫困人群。     

新能源汽车产业商业模式创新多要素联动机制研究 ———基于创新生态系统视角

基于创新生态系统理论和种群关系理论,将我国新能源汽车产业上市公司划分为不同生态位 企业种群。 运用模糊集定性比较分析法,从资源基础、企业家精神、技术创新、激励水平和环境动态性 5 个维度出发,探究不同生态位新能源汽车企业种群商业模式创新的联动机制。 研究结果表明:低生态位 企业种群存在“技术创新-激励水平”“技术创新-环境动态性”两种高水平商业模式创新联动机制;中生 态位企业种群主要通过内部资源基础和企业家精神驱动来实现商业模式创新发展;高生态位企业种群存 在“企业家精神-环境动态性”“企业家精神”“激励水平-环境动态性”三种商业模式要素联动机制。     

On the logic of common belief and common knowledge

The paper surveys the currently available axiomatizations of common belief (CB) and common knowledge (CK) by means of modal propositional logics. (Throughout, knowledge — whether individual or common — is defined as true belief.) Section 1 introduces the formal method of axiomatization followed by epistemic logicians, especially the syntax-semantics distinction, and the notion of a soundness and completeness theorem. Section 2 explains the syntactical concepts, while briefly discussing their motivations. Two standard semantic constructions, Kripke structures and neighbourhood structures, are introduced in Sections 3 and 4, respectively. It is recalled that Aumann's partitional model of CK is a particular case of a definition in terms of Kripke structures. The paper also restates the well-known fact that Kripke structures can be regarded as particular cases of neighbourhood structures. Section 3 reviews the soundness and completeness theorems proved w.r.t. the former structures by Fagin, Halpern, Moses and Vardi, as well as related results by Lismont. Section 4 reviews the corresponding theorems derived w.r.t. the latter structures by Lismont and Mongin. A general conclusion of the paper is that the axiomatization of CB does not require as strong systems of individual belief as was originally thought — onlymonotonicity has thusfar proved indispensable. Section 5 explains another consequence of general relevance: despite the infinitary nature of CB, the axiom systems of this paper admit of effective decision procedures, i.e., they aredecidable in the logician's sense.     

Measuring credibility of compensatory preference statements when trade-offs are interval determined

This paper studies how an overall fuzzy preference relation can be constructed in the compensatory context of the simple additive difference model, when imprecision on the trade-offs has to be taken into account. Three credibility indices of preferences are analysed and illustrated by a numerical example. Arguments are presented supporting the use of the third index, for which an interesting transitivity property (which was an open problem) is proved.     

Finite mixture models with concomitant information: assessing diagnostic criteria for diabetes

The World Health Organization (WHO) diagnostic criteria for diabetes mellitus were determined in part by evidence that in some populations the plasma glucose level 2 h after an oral glucose load is a mixture of two distinct distributions. We present a finite mixture model that allows the two component densities to be generalized linear models and the mixture probability to be a logistic regression model. The model allows us to estimate the prevalence of diabetes and sensitivity and specificity of the diagnostic criteria as a function of covariates and to estimate them in the absence of an external standard. Sensitivity is the probability that a test indicates disease conditionally on disease being present. Specificity is the probability that a test indicates no disease conditionally on no disease being present. We obtained maximum likelihood estimates via the EM algorithm and derived the standard errors from the information matrix and by the bootstrap. In the application to data from the diabetes in Egypt project a two-component mixture model fits well and the two components are interpreted as normal and diabetes. The means and variances are similar to results found in other populations. The minimum misclassification cutpoints decrease with age, are lower in urban areas and are higher in rural areas than the 200 mg dl^-1 cutpoint recommended by the WHO. These differences are modest and our results generally support the WHO criterion. Our methods allow the direct inclusion of concomitant data whereas past analyses were based on partitioning the data.     

Circuit optimization via sequential computer experiments: design of an output buffer

In electrical engineering, circuit designs are now often optimized via circuit simulation computer models. Typically, many response variables characterize the circuit's performance. Each response is a function of many input variables, including factors that can be set in the engineering design and noise factors representing manufacturing conditions. We describe a modelling approach which is appropriate for the simulator's deterministic input–output relationships. Non-linearities and interactions are identified without explicit assumptions about the functional form. These models lead to predictors to guide the reduction of the ranges of the designable factors in a sequence of experiments. Ultimately, the predictors are used to optimize the engineering design. We also show how a visualization of the fitted relationships facilitates an understanding of the engineering trade-offs between responses. The example used to demonstrate these methods, the design of a buffer circuit, has multiple targets for the responses, representing different trade-offs between the key performance measures.     

宏观连续交通流数值模拟

应用交通流宏观连续模型,模拟上下游信号灯作异步周期变化的协调信号灯路段的交通流动,经数值计算比较,选择改进Ｍｕｒｍａｎ格式求解．结果表明：改进Ｍｕｒｍａｎ格式能准确捕捉交通流中无振荡“激波”位置．     

Retirement patterns in Hong Kong: a censored regression analysis

This paper provides an overview of retirement patterns in Hong Kong on the basis of limited data. A censored regression model is used to infer the retirement age from people‘s current retirement status and their current age. This model is equivalent to a restricted probit model, and the interpretation of parameters is straightforward. The results clearly show a negative income effect on the retirement decision. The retirement age seems to be positively related to lifetime earnings but negatively related to the rate of decline of earnings with age. JEL classification: C24, J14, J26 Received May 6, 1996 / Accepted February 5, 1997