Search

Cranes often play a central role in transporting materials on building construction sites and are therefore critical to project cost and schedule. This paper presents a new model to simulate the interactions between mobile cranes and associated work crews onsite. The model considers crane type and position, the sequence of components transported, and the number and size of crews at the demand point. A novel hybrid multi-objective Genetic Algorithm (MOGA) is utilized to identify optimal crane and crew configurations that minimize construction cost and duration. The proposed method is demonstrated on an example problem involving the installation of curtain wall panels for a mid-rise office building. The results indicate that considering crane and crew decisions in parallel reduces installation cost by 19.5% and duration by 1.7% compared to considering these decisions sequentially. Furthermore, the number of crews used and the number of crane stops had the most significant impact on project cost and schedule, respectively.

With the environmental protection requirements of smart grid in China, the power electronic technology has been developed rapidly, which greatly promotes the development of FACTS and HVDC. Based on the development requirements of facts and HVDC in China, modular multilevel converter (hereinafter referred to as MMC) has become the core component of high voltage converter, which has many advantages, such as modular design, high output waveform quality, active power troubleshooting control, high reliability, etc. MMC is a new type of voltage source converter, which is suitable for many occasions, such as new energy grid connection, island power supply, large city power supply, etc. With the continuous increase of voltage level in China, the requirements of MMC for power supply companies are gradually improved. At present, computer simulation analysis has been applied to the research of MMC, which can help designers to optimize the scheme better. Therefore, this paper analyzes the equalization control of MMC capacitor voltage (hereinafter referred to as CV). Through computer simulation and analysis of control parameters, the voltage sharing optimal control (hereinafter referred to as VSOC) of MMC is carried out, which solves the current flexible DC transmission system.