Emerging Challenges in the Completion of Construction Projects through Public Private Partnerships: Empirical Literature Review

The process of engaging private sector in the provision of public infrastructure can improve economic value in service delivery and enable the government to utilize the capabilities and expertise held by private sector. This has a positive impact on the public in terms of improving their well-being. This literature review attempts to compare the challenges encountered in implementation of PPP projects across the world, with a view to determining cross cutting challenges and recommendations for developing countries. A literature review was conducted for empirical studies focusing on construction projects. The studies are reviewed by analyzing the methodology used and conclusions made to identify the geographical study area, Public Private Partnership project financing model, emerging challenges and recommendation for future project management. The literature search was based on four keywords: construction projects, completion of construction projects, public private partnership, challenges in construction projects. Thus, a total of 11 empirical studies were identified for review in Europe, Asia and Africa. The review revealed that most risk factors affecting project completion can be categorized as human and organizational factors and unknown geotechnical conditions that were not known beforehand. Specifically, project owners’ interference was also attributable to delays with the delays having significant implications for project execution. Risks have great impact on the performance of construction projects because they affect their quality, time and cost. The general remedy to such potential risk factors is adoption of reliable prediction mechanisms which would estimate those factors using a probabilistic model that does not rely on expert judgments as they tend to be unreliable.

PROJECTED GRADIENT DESCENT BASED ON SOFT THRESHOLDING IN MATRIX COMPLETION

Matrix completion is the extension of compressed sensing.In compressed sensing,we solve the underdetermined equations using sparsity prior of the unknown signals.However,in matrix completion,we solve the underdetermined equations based on sparsity prior in singular values set of the unknown matrix,which also calls low-rank prior of the unknown matrix.This paper firstly introduces basic concept of matrix completion,analyses the matrix suitably used in matrix completion,and shows that such matrix should satisfy two conditions:low rank and incoherence property.Then the paper provides three reconstruction algorithms commonly used in matrix completion:singular value thresholding algorithm,singular value projection,and atomic decomposition for minimum rank approximation,puts forward their shortcoming to know the rank of original matrix.The Projected Gradient Descent based on Soft Thresholding(STPGD),proposed in this paper predicts the rank of unknown matrix using soft thresholding,and iteratives based on projected gradient descent,thus it could estimate the rank of unknown matrix exactly with low computational complexity,this is verified by numerical experiments.We also analyze the convergence and computational complexity of the STPGD algorithm,point out this algorithm is guaranteed to converge,and analyse the number of iterations needed to reach reconstruction error.Compared the computational complexity of the STPGD algorithm to other algorithms,we draw the conclusion that the STPGD algorithm not only reduces the computational complexity,but also improves the precision of the reconstruction solution.

A Successful Scientific Cooperation——Smooth Completion of a Sino-Japanese Joint Research Project of Well-off Household Residences.

On February 24, 1993, when the appraisal meeting of the Sino-Japanese Joint Research Project of Well-off Household Residences was held in Beijing, Person-in-charge from the China Building Technology Development and Research Centre and the Japan International Cooperation Undertakings Group signed the project appraisal report. It marked the successful completion of this three-year joint research project.

Successful Completion of AI-Ahmadi Refinery Restoration Project in Kuwait

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A new analytical algorithm for computing probability distribution of project completion time

An analytical algorithm was presented for the exact computation of the probability distribution of the project completion time in stochastic networks,where the activity durations are mutually independent and continuously distributed random variables. Firstly,stochastic activity networks were modeled as continuous-time Markov process with a single absorbing state by the well-know method of supplementary variables and the time changed from the initial state to absorbing state is equal to the project completion time.Then,the Markov process was regarded as a special case of Markov skeleton process.By taking advantage of the backward equations of Markov skeleton processes,a backward algorithm was proposed to compute the probability distribution of the project completion time.Finally,a numerical example was solved to demonstrate the performance of the proposed methodology.The results show that the proposed algorithm is capable of computing the exact distribution function of the project completion time,and the expectation and variance are obtained.

Shanghai 500-kV Jing’an transmission & substation project completed

On April 16, the 500-kV Jing’an transmission & substation project in Shanghai, a super-large, multi-voltage level, all-underground, full digital intelligent substation, was completed and put into operation,

Expansion Project Completed at Yangtze Petrochemical Company

Renovation of the 650,000-ton ethylene unit was wound up at Yangtze Petrochemical Company Limited on July 26, which draws an investment of 4.352 billion yuan. The renovation project boosts the annual ethylene production capacity of Yangtze Company to 650,000 tons from 400,000 tons, the polyethylene and polypropylene capacity to 400,000 tons from 200,000 tons, the butadiene capacity to 200,000 tons from 100,000 tons and the gasoline hydrorefining capacity to 500,000 tons from 300,000 tons.

First phase project of Huaneng Yingkou Cogeneration Plant completed

On December 2, 2009, Unit 1 of Huaneng Yingkou Cogeneration Plant smoothly passed 168-hour triaoperation. 11 days later, Unit 2 also successfully passed the trial operation. The project

稀疏阵列的鲁棒矩阵填充DOA估计算法

稀疏阵列布阵灵活,增大阵列孔径的同时还能减少阵元间耦合,但基于稀疏阵列的传统波达方向估计会导致角度模糊混叠,带来估计精度差和稳健性不足的问题。针对以上问题,提出一种适用于稀疏阵列波达方向估计的加权截断奇异值投影(weighted truncated singular value projection,WT-SVP)的鲁棒矩阵填充算法。在填充迭代过程中根据奇异值的大小分配权重,突出大奇异值包含的阵列信息,减少小奇异值中不必要的噪声信息,从而优化传统奇异值投影算法。该算法可以实现稀疏阵列的孔洞信息恢复,对不连续阵元充分利用,同时WT-SVP填充算法实现了稀疏阵列波达方向估计的高精度、高分辨以及在低信噪比、低快拍时的高鲁棒性。

高反光物体的局部点云孔洞补全方法

针对高反光物体点云数据存在噪声明显、孔洞过大,使用传统贪婪投影三角化算法无法达到点云补全目的的问题,提出一种改进的贪婪三角化点云补全算法。利用统计滤波和高斯滤波进行离群点去除和平滑处理;采用移动最小二乘法对局部点云进行上采样增强数据,并且对点云进行进一步平滑。将贪婪三角化算法中的kd树(k-dimensional tree)算法替换为效率更高的八叉树(octree)搜索算法,将主成分分析法替换为准确率更高的移动最小二乘法进行法线估计;最后,进行点云三角化,完成点云补全。实验结果表明,改进算法能够更好地补全孔洞,补全后表面更加平滑、结构更为准确,且花费时间更短。

初探水电工程建设征地移民安置竣工验收主要问题的处理措施--以云南省金沙江中游大型水电工程为例

依托云南省已实施完成的金沙江中游6座大型水电站工程建设征地移民安置竣工验收工作实践情况,从验收依据、验收内容以及工作组织管理等方面分析制约水电工程建设征地移民安置竣工验收的主要问题,提出高位推动、调整规划、资金保障、工作大纲、技术支撑、资金清理审计与档案专项验收等工作的成功经验与对策措施。

基于Internet的质量工作人员调配和完工数据计算方法

在海洋工程项目的质量工作开展过程中,由于施工人数多、所属工种多,给人员管理和完工检验等方面带来了较多问题。以前后端分离的网页形式,编写了基于Internet的人员调配和完工数据计算方法,在巴油P79等多个海洋工程项目中运行,提质增效显著。该方法实现了线上录入基础信息,导出人员动态表和施工人员配比,计算项目完工数据,提高了质量管理工作的效率,为制定人力计划提供参考,并为后期管理类似项目提供了有力支撑。

化工项目竣工环保验收监测检查的实施分析

化工项目建设过程所涉及材料较为复杂,当整体项目完成之后,需要进行竣工验收,并且需要重点展开环保验收检测,确定整体项目污染排放以及相关治理工作是否达标。通过以新疆昆玉钢铁有限公司200万t/a钢铁及配套循环经济综合利用项目为例,对化工项目竣工环保验收检测检查实施方式方法进行分析探究,期望能够为相关工作开展提供一些启示。