This study deals with the balancing problem of a manual mixed-model assembly line, where the production volume or the product mix changes from shift to shift during the planning horizon. The unstable demand can be characterised by several representative scenarios, and the line uses overtime work to meet the demand variation. The balancing problem concerns how to assign assembly tasks to stations and determine the amount of overtime in each possible demand scenario. The objective is to satisfy the demand in each possible scenario with the minimum labour costs paid for both normal shifts and overtime work. A lower bound on the labour costs is proposed, and a heuristic algorithm is developed to quickly find a feasible solution. A branch, bound and remember (BB&R) algorithm is then proposed to find better solutions. These solution methods are tested on 765 instances. The BB&R algorithm obtains optimal solutions for 510 instances and gives high-quality solutions for the remaining 255 instances within 60 s. The experimental results show that the use of overtime work and adjustable cycle times significantly reduces the labour costs, especially when the demand or task processing time variations are large.

Coal gangue, an industrial waste, is rich in silicon and aluminum phase and may be used as a mineral admixture in concrete after moderately stimulating activity, allowing for efficient solid waste utilization. This study used a mortar strength and activity evaluation method to investigate single or compound activation methods to find the optimum activation method of coal gangue. FLIR, XRD, and SEM were used to investigate the activation mechanism of different modes, providing a theoretical foundation for the study of coal gangue as a concrete admixture. Results showed that mechanical ball milling, microwave, and chemical activator could activate coal gangue, and the composite activation effect was the best. The fineness of the coal gangue powder was more than 300 mesh, according to the optimal compounding method. Accordingly, the particle surface was smooth, the internal defects were reduced, and the microwave irradiation temperature was 700°C–800°C, causing the coal gangue particles to form a bonding surface and gradually agglutinate and densify. Meanwhile, the layered structure of kaolin minerals was destroyed, and a significant amount of glassy active SiO₂ and Al₂O₃ was produced, enhancing the gel ability and activity of coal gangue. Finally, 8% Ca(OH)₂ was added in the production of mortar specimens, which increased the alkalinity of the slurry, stimulated the rapid cracking and secondary hydration of the coal gangue, and enhanced the strength of mortar. At this time, the activity rate of coal gangue powder reached the highest, which was 90.5%.

Employee security compliance behavior has become an important safeguard to protect the security of corporate information assets. Focusing on human factors, this paper discusses how to regulate and guide employees’ compliance with information security systems through effective methods. Based on protection motivation theory (PMT), a model of employees’ intention to comply with the information security system was constructed. A questionnaire survey was adopted to obtain 224 valid data points, and SPSS 26.0 was applied to verify the hypotheses underlying the research model. Then, based on the results of a regression analysis, fuzzy set qualitative comparative analysis (fsQCA) was used to explore the conditional configurations that affect employees’ intention to comply with the information security system from a holistic perspective. The empirical results demonstrated that perceived severity, perceived vulnerability, response efficacy, and self-efficacy all positively influenced the employees’ intention to comply with the information security system; while rewards and response costs had a negative effect. Threat appraisal had a greater effect on employees’ intention to comply with the information security system compared to response appraisal. The fsQCA results showed that individual antecedent conditions are not necessary to influence employees’ intention to comply with an information security system. Seven pathways exist that influence an employees’ intention to comply with an information security system, with reward, self-efficacy, and response cost being the core conditions having the highest probability of occurring in each configuration of pathways, and with perceived severity and self-efficacy appearing in the core conditions of configurations with an original coverage greater than 40%. Theoretically, this study discusses the influence of the elements of PMT on employees’ intention to comply with an information security system, reveals the mechanism of influence of the combination of the influencing factors on the outcome variables, and identifies the core factors and auxiliary factors in the condition configurations, providing a new broader perspective for the study of information security compliance behavior and providing some theoretical support for strengthening enterprise security management. Practically, targeted suggestions are proposed based on the research results, to increase the intention of enterprise employees to comply with information security systems, thereby improving the effectiveness of enterprise information security management and the degree of information security in enterprises.