## 4 Assembly Line Balancing Problems with Stochastic or Fuzzy Parameters
### Assembly and Production Line Balancing Problems with Fuzzy Parameters
The effectiveness of the developed fuzzy control was demonstrated. The intelligent automation can improve the performance of the assembly process by the proposed fuzzy control system since real-time information of the assembly line can be used for the adaptive decision-making. In [98], a fuzzy control system was developed to analyze real-time information of the assembly line with two types of fuzzy controllers. The first type of a fuzzy controller was used to determine whether the assembly line should be re-balanced to satisfy the changed product demands. The second type of fuzzy controller was used to adjust the production rate of each workstation in time, to eliminate blockage and starvation. Hence, the utilization of available workstations increased. Compared with the three assembly lines without the fuzzy control system, the assembly line with the fuzzy control system performed better in terms of the blockage ratio, the starvation ratio and the buffer level. With the improvement of information transparency, the performance of assembly line production was better. The research findings shed light on the smart control of the assembly line production and provide insights into the impacts of Industry 4.0 on the ALBP. Summarizing the above results published in the papers [88; 89; 86; 87; 83; 88; 89; 26; 33; 38; 39; 38; 37; 36; 33; 39; 40; 41; 42; 43; 44; 45; 46; 47; 48;  
planning may involve three steps, as follows: to decide whether the disassembly mode should be complete or partial, to construct a disassembly model by preventing the generation of unfeasible disassembly sequences and to employ a selected planning algorithm according to the disassembly objective and the used optimization models and techniques. The articles [25; 31; 101; 102] investigated the disassembly line balancing, which may consist of the aggregate machines, mechanisms and devices located in accordance with the sequence of operations of the technological process of disassembling the obsolete product and transport devices that move the disassembled product. The duration of disassembly operations cannot be accurately determined but a few studies are published on the DLBP with inaccurate durations of disassembly operations. The timely recovery and disassembly of waste electronic and electrical equipment obtained a higher economic benefit and can reduce the impact of hazardous substances on the environment. The parallel disassembly line can disassemble different types of waste electronic and electrical equipment and improve the disassembly efficiency. A parallel disassembly line balancing model with stochastic disassembly times is studied in [102]. The evaluation index of the disassembly line includes a number of workstations, workload smoothness and disassembly profits. A genetic simulated annealing algorithm was proposed to optimize a disassembly line balance. The decoding and encoding strategies were proposed based on characteristics of a partial disassembly and parallel layout. Two-point mapping crossovers and single-point insertion mutations were designed to ensure that the disassembly sequence meets the given precedence and disassembly constraints. The simulated annealing algorithm was applied to the results obtained by the genetic operation. The proposed algorithms obtain better solutions than a tabu search for stochastic parallel DLBP. The proposed algorithm has a better performance than the CPLEX solvers, genetic algorithms and simulated annealing algorithms for parallel DLBP. Parallel disassembly lines for waste refrigerators and televisions were constructed. The performance of the proposed multi-objective algorithm was superior to those of five other multi-objective algorithms. The computational results showed that the proposed model and algorithms have better practical application ability.