Estimation of linear models with nequal restrictions

Inequality constrained regression involves the notion of a truncated parameter space, which was studied extensively by Moors (1985). His general results are extended here and applied to linear models. Using the invariance principle, for every observation x a set V_x is defined with the property that estimators taking values in V_x (with positive probability) are inadmissible. One of the main conclusions is that the usual estimators in inequality constrained regression are inadmissible; a method to obtain better estimators is indicated.     

On optimal allocations for estimating the surface of a random field

In general, the construction of optimal designs is apparently a difficult task for the approximation of a random field indexed by more than one dimension. Besides the rate of convergence of the minimum achievable error hardly anything is known until now. However, if there is an immanent structure present in the random field, then, taking this structure into account, improved estimates can be obtained. For this situation we present adequate designs which show, at least, a nearly optimal performance. work supported by 313/ARC/VII/93/151 of the DAAD work supported by Ku719/2-1 of the DFG     

山东省农业现代化发展水平时空演变及障碍因子研究

目的 十四五时期,我国将进入农业现代化发展的关键阶段。分析、评价农业现代化发展水平、区域分异特征及障碍因子,有助于科学地把握区域农业现代化的发展规律,更好地推动农业现代化的发展。方法 文章依据现有的研究成果,从农业投入、农业产出、农业科技发展、农业产业化发展、农村社会发展和农业绿色发展6个维度选取21个代表性指标构建了农业现代化评价指标体系,基于2010—2019年山东省统计数据,运用熵值法、空间自相关模型和障碍度模型,分析山东省农业现代化的发展状况以及各地市发展水平的差异,探讨影响农业现代化发展的障碍因子。结果 2010—2019年山东省农业现代化发展水平综合得分由0.143稳步上升到0.778。就区域分异特征而言,鲁东及鲁中地区发展较快,鲁西南地区发展滞后。不同时间段制约农业现代化发展的主要障碍因子有所不同,农业科技成果数量和农产品加工企业个数成为近年来影响其发展的主要障碍因子。结论 提出优化农产品加工产业布局、增强科技创新能力、提升农产品出口质量、落实惠农强农政策和加强区域间的农业交流合作等建议,更好地推动农业现代化的发展。     

小半径曲线箱梁预应力钢束张拉施工技术

以阿拉乡互通立交桥A匝道桥曲线梁的预应力张拉施工为例,介绍了小半径曲线箱梁预应力钢束张拉施工阶段的技术控制要点,通过该项工程施工的成功验证,对同类型曲线梁桥预应力张拉施工有一定的参考价值。     

高层建筑结构设计中常见问题及处理措施

高层建筑相对于普通工民土建建筑设施要求较高。目前我国在高层建筑结构设计中存在多种问题,给建筑的实际施工和日常使用管理带来巨大的困难。     

港口物流集聚动力空间及其对区域经济的效应分析

采用洛伦兹曲线分析港口物流集聚程度,并分析港口物流集聚的技术驱动力、区位驱动力、市场驱动力、经济驱动力和政策驱动力五大驱动力机制,然后采用Logistic模型分析港口物流集聚动力空间对区域经济的影响效应。     

低碳城市发展地域系统优化研究：以上海临港新城为例

城市地域系统的结构决定了城市低碳发展的基础。在反思传统城市地域系统规划低碳发展的局限性基础上,以临港新城低碳城市地域系统优化案例为研究对象,对空间结构、土地利用、交通体系等城市地域系统核心构成要素进行低碳优化分析。研究指出低碳城市地域系统在空间结构上具有高密度、高容积率、高层的紧凑型特征,多中心的梯级空间格局,分散组团式的空间开发;集约化、多样化的复合功能的土地开发;公共交通导向的走廊式空间规划,发达的小地域空间道路体系等特点。     

Bayesian inference for nonlinear structural time series models

We consider efficient methods for likelihood inference applied to structural models. In particular, we introduce a particle filter method which concentrates upon disturbances in the Markov state of the approximating solution to the structural model. A particular feature of such models is that the conditional distribution of interest for the disturbances is often multimodal. We provide a fast and effective method for approximating such distributions. We estimate a neoclassical growth model using this approach. An asset pricing model with persistent habits is also considered. The methodology we employ allows many fewer particles to be used than alternative procedures for a given precision.     

Social protection in Lesotho: Innovations and reform challenges

Given its current socioeconomic conditions and fiscal ability, Lesotho has achieved an impressive record in creating a basic social assistance and social protection system, informed by political commitment and through budget reprioritisation. It has set up and administered near universal schemes operating at scale with fairly low transaction costs, addressing core areas and serving vulnerable constituencies – including the aged, orphaned and vulnerable children and children of school-going age. A contribution-based comprehensive national social security scheme to provide coverage for Lesotho workers and their families is also planned. Nevertheless, the task of providing adequate social protection coverage faces systems and delivery challenges; several human development indicators have worsened, and most of the Millennium Development Goals are far from being achieved. There is scope for creating greater fiscal space by establishing a compulsory national contributory scheme, and donor support in the short to medium term is inevitable.     

A short-term flight scheduling model for international express package delivery

A short-term flight scheduling model for air express carriers is developed to determine suitable routes and flight schedules with the objective of minimizing operating costs, subject to related operating constraints. The model is formulated as an integer multiple commodity network flow problem solved using mathematical programming. For evaluation, a case study is used based on the operating data from a major international air express carrier.