Qi Guo

This study aims to identify and quantify the critical factors influencing construction labor productivity. A systematic review and meta-analysis of 27 empirical studies published between 2000 and 2024 were conducted in accordance with PRISMA guidelines. This study synthesizes findings from a variety of global studies and calculates the relative importance index of various factors affecting construction labor productivity. The findings indicate that 66 CFs, categorized into 12 groups, influence construction labor productivity. The results findings underscore the pivotal role of labor-related factors, particularly “worker experience and skills”, and site management factors, such as “competent supervisors” and “effective communication”. Additionally, environmental factors, such as “weather conditions”, have been demonstrated to play a significant role. The meta-analysis identified substantial regional variations and an increasing importance of factors like worker motivation and technological advancements. Moreover, in light of the evident disparities among regional influential factors, including but not limited to climate, economics, and culture, the findings of this study underscore the imperative for customized, localized management methodologies to enhance construction labor productivity, which will provide practical suggestions for project managers in the region and globally.

With the rapid development of a new power system under the “dual carbon” goal, pumped storage has gained increasing attention for its role in integrating renewable energy and enhancing power system flexibility and security. This study proposes a dynamic benefit evaluation method for pumped storage projects, addressing the limitations of static analyses in capturing the evolving benefit trends. In this paper, the multi-stage dynamic benefit evaluation model was constructed by introducing time-of-use tariffs, periodic capacity pricing mechanism, and ancillary service revenue prediction based on machine learning and the multiple regression method. Sensitivity analysis was applied to explore the impact of key parameter variations on economic indicators. The results show that the benefit structure differs significantly across stages, and with electricity market development, a diversified pattern supported by electricity, capacity, and ancillary service revenues will emerge. The application of the model to an actual operating pumped storage power station yielded an internal rate of return of 8.18%, a payback period of 16.4 years, and a 26% increase in net present value compared with traditional methods. The proposed model expands the theoretical framework for pumped storage benefit evaluation and provides strong support for investment decisions, policy design, and operational strategy optimization.

Driven by the “dual carbon” target, the new power system transformation is facing challenges in system stability and economy brought by the new energy’s multi-temporal and spatial uncertainties. Pumped storage is a good response to these challenges by providing multiple-time-scale energy storage to improve the grid security level and power energy quality and achieve economical and energy–saving operation of the power grid. Starting by analyzing the main challenges faced during the power system transformation process, this study summarizes the current research status of pumped storage in China in terms of functional application scenarios, technological innovations, economic benefits, and environmental benefits. Then, a multi-objective optimization model of the combined wind-photovoltaic-thermal-pumped storage system is developed to provide preliminary ideas for addressing the current challenges. Finally, we discuss the scientific issues that need to be focused on in order to maximize the benefits of pumped storage from the technical, economic, and environmental perspectives and propose future research directions based on international experience. The results show that the established model can effectively improve the economic return of the system and reduce the volatility of the power grid connection. At the same time, it can promote the efficient utilization of new energy, and the model has high feasibility. In the future, we should carry out in-depth research on the principles of pumped storage participation in multi-energy complementation across multi-temporal and spatial scales, vigorously promote technological innovation and upgrading, explore the market-oriented revenue return mechanisms reflecting the value contribution of pumped storage, and strengthen the energy and environmental management of pumped storage power stations. The research in this paper takes into account both macro and micro-level scientific issues and provides ideas for efficiently addressing key challenges in the new power system transformation.

Recently, engineering bidding has emerged as a critical factor in driving infrastructure and economic development globally. However, the construction industry continues to grapple with numerous challenges in this area. Existing research, though encompassing diverse themes, remains highly fragmented, lacking a systematic framework and in‐depth analysis of the internal logic among various themes, making it difficult to provide comprehensive guidance. To address these gaps, this paper innovatively employs a mixed‐methods approach, integrating systematic review, bibliometrics, multiindicator comprehensive evaluation, and correlation analysis to analyze 510 pieces of literature in the China National Knowledge Infrastructure (CNKI) and Web of Science (WOS) databases from 2003 to 2023. Considering China’s legal, policy, and economic landscape, alongside a comparative analysis of international studies, this paper aims to reveal the research hot topics and evolutionary trends in engineering bidding and tendering sector, offering forward‐looking recommendations for future research directions and applications. The findings indicate that project management issues and practices, collusive behaviors, bidding management, and decision issues as well as bid evaluation methods, are poised to dominate future research endeavors in this field. China can draw on international experiences in technology, legislation, procedure, and system to enhance the transparency and efficiency of bidding and tendering activities. The research framework and methodological approaches in this paper break through a single mode of analysis, both systematic and applicable, and can offer valuable insights for bidding and tendering research in diverse national contexts.

Labor productivity exerts a significant influence on the construction cycle and investment in hydropower projects. Consequently, it is a crucial factor in the estimation of the cost of hydropower project construction. The mechanisms that are modulated by subjective factors have been extensively studied. However, the assessment of labor productivity in objective environments with regular changes is usually considered using a single factor, especially in special environments where the influence of environmental factors is of greater concern. As the most extensive region of China’s water-energy resources, the Southwest region has a lengthy tradition of using altitude or oxygen as an inherent criterion for the assessment of labor productivity. However, the applicability of inherent standards is limited. Therefore, we tried to assess the spatial and temporal changes in labor productivity based on the changes in meteorological conditions in Southwest China, employing climate comfort indicators in this study. The result identified five distinct regions of climate change in Southwest China (R-I to R-V). In particular, there is minimal variation in labor productivity as assessed by climate comfort indicators and the elevation between R-I and R-II. R-III and R-IV are influenced by oxygen, temperature, and humidity, while R-V is affected by a multitude of factors. Our findings indicate that temporal and spatial variations in meteorological conditions can result in up to a threefold difference in productivity at the same altitude in different regions. Importantly, our study provides valuable theoretical insights for engineering project management. In particular, it can be concluded that altitude is not a reliable indicator for evaluating labor productivity in high-altitude construction.

The revenue of a public-private partnership (PPP) project is influenced by macroeconomic scenarios such as economic recession and policy adjustments. But these macrofactors and their dynamic relations with microfactors in PPP projects have not been thoroughly understood. In this article, system dynamics (SD) and real option (RO) are integrated to develop a novel model to investigate the impacts of the macro-risk factors on the revenue of PPP projects. Five scenarios were studied through simulation. The results indicate that the loan interest rate and tax rate are negatively correlated to the revenue, while the GDP growth rate and self-owned capital rate are positively correlated. This indicates that the government can stimulate the private sector to invest in PPP projects by providing lower loan interest and increasing the self-owned capital rate. This integrated approach has been proposed for use by decision-makers to evaluate the impact of economics and policies in the future. This study provides a comprehensive review and reliable theoretical analysis regarding the adoption of PPP by China’s local governments, yielding to main policy implications for further promoting the efficiency of PPP development.

Many sewage treatment facilities in China have been developed and operated using the Public-Private Partnerships (PPP) model. However, a big challenge faced by these PPP projects is that the subsidy requested from the government during the operation is normally higher than what was estimated originally, thus often exceeding the budget that the government can afford. This leads to a high risk of project failure or insufficient operation. This problem is largely caused by the uncertainties exhibited in the existing models, such as the Black-Scholes (BS) model. While being used in the budget estimation, these models cannot sufficiently account for the short-term uncertainty that may be incurred during the operation of projects. In this study, a method to account for this short-term uncertainty has been proposed to improve the BS model. This allows for investigations to address issues related to how the real option value of a government subsidy is affected. A Monte Carlo simulation was performed to take into account the noise in the estimation. A sensitivity analysis further revealed that this discrepancy is largely affected by the values of the relevant parameters in the short-term uncertainty model. We found that the short-term uncertainty has a significant effect on private revenue and government subsidy and that the changes of the latter are more sensitive to the change of short-term uncertainty. The value of the relevant variables of short-term uncertainty determined the fluctuation of the revenue. The mean value and revenue had a positive correlation. The reverting speed and revenue showed a negative correlation. The short-term volatility had a positive correlation toward the fluctuation range of the revenue. The simulation results indicate that this enhanced method can produce more accurate information for a better assessment of the PPP project under a wide range of uncertainty scenarios, allowing for the best decision making by the government.

Based on the transaction cost theory, analyses the reason of the emergence and development of EPC contract mode, establishes transaction cost model under the traditional mode and the EPC contract mode, which divides the transaction costs into three parts: the contracting cost, the cost for coordination and supervision cost, and make a comparative analysis of the transaction cost between the traditional mode and the EPC contract mode according the three parts respectively. Reach to a conclusion that in EPC contract mode, the uncertainty of EPC projects transaction cost increased and become the key factor of transaction cost controlling while the supervision cost and coordination cost reduced. So only see from the aspects of the transaction cost, EPC contract mode is not suitable for all kinds of projects, the contracting cost between the owner and the general contractor become the key factor during the decision-making process.

This paper discusses the problem of mixed H 2 /H ∞ filtering for continuous-time systems. In the case where the state-space matrices of the system depend affinely on the uncertain parameters, it is known that recently developed extended or dilated linear matrix inequalities (LMIs) are effective to assess the robust performance in a less conservative fashion. In this paper, the filter is designed by using different Lyapunov matrices to the mixed performances. These ideas are realized by introducing additional slack variables to the well-established performance conditions and by employing new bounding techniques, which results in a much less conservative filter design method. A numerical example is presented to illustrate the effectiveness and advantage of the developed filter design method