A permutation-combination heuristics for crane-based automated storage and retrieval systems considering order fulfillment time and energy consumption

An automated storage and retrieval system (AS/RS) is a key component of enterprise logistics. Its performance metrics include, e.g., order fulfillment time and energy consumption. A crane-based automated storage and retrieval system (CB-AS/RS) is used as the study subject in this paper to build a location allocation model with the goal of minimizing order fulfillment time and minimizing energy consumption. The two-objective problem is transformed into a single-objective problem by the weight method. A genetic algorithm (GA) is used to optimize and simulate the model using spatial mapping coding. A permutation-combination heuristics (PCH) is proposed that follows the coding method and cross-operation of the GA and conducts both arrange-operation and change-operation. During the simulation, the influence of different storage utilization rates and different output and input instruction quantities in a batch of orders on the results is considered. Experimental results show that the results of the PCH algorithm are better than the GA and the optimization results are more stable. In this paper, we provide an optimization idea for the CB-AS/RS researchers and managers.

Application of PVAR model in the study of influencing factors of carbon emissions

Based on the panel data of China from 2003 to 2017, this paper applies the panel vector autoregressive (PVAR) model to the study of the influencing factors of carbon emissions. After the cross-section dependence test, unit root test and cointegration test of panel data, the dynamic relationship between energy consumption, economic growth, urbanization, financial development and CO₂ emissions is investigated by using PVAR model. Then, we used the impulse response function tool to better understand the reaction of the main variables of interest, CO₂ emissions, aftershocks on four factors. Finally, through the variance decomposition of all factors, the influence degree of a single variable on other endogenous variables is obtained. Overall, the results show that the four factors have a significant and positive impact on carbon emissions. In addition, variance decomposition also showed that energy consumption and economic growth strongly explained CO₂ emissions. These results indicate that the financial, economic and energy sectors of China's provinces still make relatively weak contributions to reducing carbon emissions and improving environmental quality. Therefore, several policies are proposed and discussed.

[Optimization of drying process for Scrophulariae Radix by multivariate statistical analysis]

To establish the suitable modern drying processing parameters for Scrophulariae Radix (SR). With reference to the traditional drying processing method of SR and the characteristics of modern drying equipment, the drying process for SR was simulated as the following three stages: temperature-controlled drying-tempering-temperature-controlled drying. Eighteen batches of SR samples were obtained by the drying methods after the orthogonal design experiment with seven factors namely temperature, wind speed, and target moisture for the first stage, tempering time and temperature, as well as temperature and wind speed for the second stage. UPLC-TQ-MS was applied for determination of nine target compounds including catalpol, harpagide, verbascoside, ferulic acid, angroside-C, aucubin, harpagoside, cinnamic acid and ursolic acid in those dried samples and another 19 batches of SR samples collected from genuine producing area. Principal Component Analysis (PCA) was performed, and total energy consumption was also taken into consideration for analysis and evaluation. Results showed that the optimal drying processing method for SR was as follows: drying temperature of 60 ℃, drying wind speed of 50 Hz, and 50% for target moisture in the first stage; 24 h for tempering time and temperature of 20 ℃ in the second stage; drying temperature of 60 ℃, and drying wind speed of 30 Hz in the third stage. The medicinal materials with optimized modern drying processing method were extremely similar to those collected from genuine producing area in the aspect of both external properties and target compounds, and they were in line with the 2015 version of "Chinese Pharmacopoeia" requirements. In addition, they could help to shorten the drying time and increase the efficiency of primary processing, and thus promote the normalization and standardization of primary drying processing for SR.