Quality self-control and co-supervision mechanism of construction agent in public investment project in China

Public investment project (PIP) plays an important role in the China economy. In order to improve the project management performance of public projects, the government is searching for a scientific system to build a construction management supervision mode. This paper introduces the policy background and connotation of Agent Construction System (ACS). As a public investment construction management model, ACS, is gradually being incorporated into the legal framework, it is necessary to improve the construction agent supervision mechanism. This article analyzes the supervision mechanism of construction agent quality management under the principle of two-stage agent mode and establishes an agent quality self-control system and a government co-supervision system. These systems take the contract management as the core and the project quality objective as the guidance. These systems also consist of a two-dimensional framework of vertical self-control and horizontal supervision, which form a quality supervision mechanism. Based on Rough Set theory, the article proposes the idea of building an agent quality self-control and government co-supervision model, and illustrates it with a flow chart for building the model, which paves the way of quantitative research for the future.     

从移民到公民——穆斯林移民融入美国主流社会的历程及其特点

以9·11为分界点,探究美国穆斯林在从移民转变为公民的过程中如何逐渐与美国主流社会相融合.9·11之前美国穆斯林与美国应流社会的交往的发展是平稳缓慢的而之后的交往则表现为激烈的碰撞与融合.事实上9·11并没有打断移民穆斯林融入美国主流社会的进程,而是这一过程表现得更加剧烈和复杂.     

Complete convergence and the strong laws of large numbers for pairwise NQD random variables

The authors study the strong convergence for sequences of pairwise negatively quadrant dependent (NQD) random variables under some wide conditions, and present some new theorems on the complete convergence and the strong laws of large numbers. The obtained results extend and improve some theorems in existing literature.     

Coordinate sampler: a non-reversible Gibbs-like MCMC sampler

We derive a novel non-reversible, continuous-time Markov chain Monte Carlo sampler, called Coordinate Sampler, based on a piecewise deterministic Markov process, which is a variant of the Zigzag sampler of Bierkens et al. (Ann Stat 47(3):1288–1320, 2019). In addition to providing a theoretical validation for this new simulation algorithm, we show that the Markov chain it induces exhibits geometrical ergodicity convergence, for distributions whose tails decay at least as fast as an exponential distribution and at most as fast as a Gaussian distribution. Several numerical examples highlight that our coordinate sampler is more efficient than the Zigzag sampler, in terms of effective sample size.     

中国城镇新增住房需求规模的测算与分析

本文围绕城镇家庭户自然增长、城镇家庭户机械增长和城镇存量住房拆除三项需求来源,设计了基于人口普查等公开统计数据定量测算城镇新增住房需求规模的系统性方法,对2001—2010年和2011—2015年间全国和各省份城镇新增住房需求规模进行测算与分析。在此期间新增住房供需关系经历了从基本均衡向供过于求的变化,同时存量住房拆除引致的被动需求取代城镇家庭户自然增长和机械增长引致的主动需求,成为新增住房需求的最主要来源。东、中、西部省份在新增需求规模、新增供需比、需求结构等方面表现出明显差异。本文还进一步对2021—2030年的发展趋 势进行了定量预测。由于三项需求来源均趋于下降,2021—2025年和2026—2030年间全国年均城镇新增住房需求规模预计将较2011—2015年间分别下降33%和53%。本文设计的城镇新增住房需求规模测算方法和预测思路能够为各级政府“十四五”住房发展规划编制、房地产企业战略制定等提供参考。     

借鉴国际经验打造我国世界级首都经济圈

国际首都经济圈均先经历极化效应后实现扩散效应,最终在一定区域内形成首都圈经济,通常由服务经济、总部经济、知识经济、绿色经济、园区经济、临轨经济、临空经济和临港经济等八大经济形态组成。通过深入研究伦敦、巴黎、东京和首尔四大国际性首都经济圈的演化路径及经验,定性与定量相结合比较八大经济形态发展态势,明确北京首都经济圈发展差距,提出实现首都经济结构发展升级必须依赖推动京津冀协同发展,建立全域性的首都圈经济。     

铝合金抽油杆柱深抽的初步研究

机抽井深抽是恢复油井产量行之有效的措施，为解决钢质杆深抽时驴头负荷、曲柄扭矩和杆柱应力过大的问题，我国西部某油田提出了使用铝合金抽油杆的设想。本主根据抽油杆柱设计理论导出了深抽杆柱各级下入深度的公式；对不同工艺参数配合下的计算结果进行了对比分析，对铝合金抽油杆柱用于深抽的可行性进行了初步研究。     

Multi-neighborhood based iterated tabu search for routing and wavelength assignment problem

The routing and wavelength assignment problem (RWA) has shown to be NP-hard if the wavelength continuity constraint and the objective of minimizing the number of wavelengths are considered. This paper introduces a multi-neighborhood based iterated tabu search algorithm (MN-ITS), which consists of three neighborhoods with a unified incremental evaluation method, to solve the min-RWA problem. The proposed MN-ITS algorithm is tested on a set of widely studied real world instances as well as a set of challenging random ones in the literature. Comparison with other reference algorithms shows that the MN-ITS algorithm is able to improve five best upper bounds obtained by other competitive reference algorithms in the literature. This paper also presents an analysis to show the significance of the unified incremental evaluation technique and the combination of multiple neighborhoods.