建筑工程招投标中控制工程造价的策略探讨

做好建筑工程项目招投标阶段的工程造价管理,可以更好保证施工企业利益。本文对建筑工程项目招投标阶段工程造价的影响因素进行分析,并提出相应的控制策略。     

基于区块链的建设项目数据穿透机制研究

从建设项目数据不透明问题的现状出发,结合“穿透”理念和区块链的技术优势,研究建设单位视角下基于区块链的建设项目数据穿透模式和实现路径。然后提出从组织穿透、过程穿透和行为穿透三个维度进行建设项目的数据穿透,并分别论述区块链如何帮助实现建设项目三维度穿透机制。最后通过案例探讨区块链带来的建设项目价值的提升。     

Field study of a retaining wall constructed with clay-filled soilbags

This paper presents a field study of constructing retaining walls using soilbags that are formed by filling the excavated clayey soils into woven bags (geosynthetics). The strength and deformation of the soilbags filled with clayey soils were studied via laboratory tests. A 100?m testing retaining wall was constructed with soilbags in a waterway project. The lateral deformation, the lateral pressures and the surface settlements of the testing retaining wall were monitored during construction and after 7 months operation. The results show that the soilbags can increase the strength of clayey soils. After 7 months of the completion, the lateral deformation and the surface settlement of the testing retaining wall tend to be stable with the maximum values of 29.4?cm and 19.2?cm, respectively. The lateral earth pressure on the front retaining structure could be positively reduced owing to the interlayer's friction of soilbags. Compared to the conventional gravity concrete retaining wall, about 38% construction cost was saved in the 100?m testing retaining wall.     

面向多表数据连接投影和连接顺序的优化方法

多表连接运算是大数据处理中常见的运算。类似于数据库运算中常见的连接操作,多表连接运算的顺序会对计算资源和传输资源的消耗产生巨大影响。对多表连接顺序的优化是一个经典的优化问题,同时每次连接中表的投影结果大小也会影响节点间传输的数据体积,因此整体连接的顺序和每次连接的投影关系都会对连接效率产生显著的影响,而在传统的优化策略中,往往不会考虑到中间投影关系的取舍问题,以及基于中间投影关系而对最优连接策略产生的影响。针对这个问题,建立了一种连接关系索引,能够在构建优化连接策略中调整每次连接的投影关系,及时删除冗余列,减少对传输资源的消耗,同时基于投影关系的优化调整连接顺序的优化策略,从全局考量上尽可能地同时减少对传输资源和计算资源的消耗。该优化策略在Flink系统实现后进行了实验,结果表明有显著的优化效果。     

基于区间犹豫模糊语言集的水资源多目标决策

以鄂北水资源配置工程为对象,研究大型调水工程背景下的多水源多目标优化配置。将鄂北地区水库分为充蓄水库、补偿水库与在线水库等3类,根据各类水库特点对鄂北水资源配置工程进行系统概化,建立以年缺水量最小和调水成本最低为目标函数的多水源多目标优化配置模型。采用权重系数法进行求解得到非劣解集。最后采用基于区间犹豫模糊语言与TOPSIS的多目标决策方法对各方案的缺水量与调水量作出评价并遴选出最优方案。研究结果表明:对鄂北水资源配置工程而言,缺水量与调水量的权重比为7∶3的方案综合评价最优,重视缺水的同时兼顾调水成本;基于区间犹豫模糊语言集与TOPSIS的水资源多目标决策方法经本文实例验证具有较高的稳定性与可行性。     

Regional consortia and transaction costs for sanitation services in Brazil

Studies on public cooperation usually focus on its impact on the service costs experienced by service providers. However, engagement in public cooperation in service provision often seeks other outcomes, like service coverage (measured by the population served) rather than simply minimizing service expenditure. Moreover, public cooperation by local governments, as either ‘providers’ or owners, generates transaction costs arising from negotiation, monitoring, agency costs and the enforcement of cooperative agreements. However, to date, little empirical effort has been directed at determining the impact of transaction costs on service provision owners and service outcomes. This paper addresses this gap in the empirical literature by examining the relationship between cooperative agreements between Brazilian municipalities for water and wastewater provision and service coverage in the light of transaction costs. We find that transaction costs are higher for cooperative providers due primarily to low service coverage levels, especially in sewage services that demand high investment in assets with high specificity. However, lower expenditures may occur after initial up-front investment.     

A clustering-based review on project portfolio optimization methods

Project portfolio management and optimization constitutes a critical activity for organizations in different industrial sectors and business. The scientific literature in this subject is extremely vast, which makes it difficult to understand the connections among the existing approaches and perspectives. This paper provides a clustering map of the existing work on the subject, thus identifying the main trends and approaches from different scientific communities. After analyzing each of the identified clusters, the paper provides insights and emerging trends that can be useful both for researchers and practitioners in the area.     

Mathematical modelling and simulation of the thermo-catalytic decomposition of methane for economically improved hydrogen production

The demand for low-emission hydrogen is set to grow as the world transitions to a future hydrogen economy. Unlike current methods of hydrogen production, which largely derive from fossil fuels with unabated emissions, the thermo-catalytic methane decomposition (TCMD) process is a promising intermediate solution that generates no direct carbon dioxide emissions and can bridge the transition to green hydrogen whilst utilising existing gas infrastructure. This process is yet to see widespread adoption, however, due to the high catalyst turnover costs resulting from the inevitable deactivation of the catalyst, which plays a decisive role in the feasibility of the process. In this study, a feasible TCMD process was identified and a simplified mathematical model was developed, which provides a dynamic estimation for the hydrogen production rate and catalyst turnover costs over various process conditions. The work consisted of a parametric study as well as an investigation into the different process modes. Based on the numerous simulation results it was possible to find the optimal process parameters that maximise the hydrogen production rate and minimise the catalyst turnover costs, therefore increasing the economic potential of the process and hence its commercial viability.     

电力工程项目管理的三要素分析

现今社会经济正在迅速发展中，电力工程领域也得到了较为良好的发展。但在此领域发展中，项目管理问题较为突显。文章主要是对电力工程项目管理的三要素进行了分析研究，以此帮助有效提升电力项目的管理工作效率及质量。