Q2. What are the future works mentioned in the paper "A survey of the assembly line balancing procedures" ?
Thus, developing procedures for the solution of SMS, MMD and MMS versions of the problem that are both capable of solving problem sizes and ¯ exible to model the actual conditions encountered in practice constitutes a future research area. Developing procedures that consider the new developments in the learning and the forgetting e ect for the mixed/multi model lines, and conducting studies that examine the e ects of these phenomena on the line balance are further research areas. Several directions for future research on the U-line balancing problem exist, including studying SMS lines and considering various new objectives. Having di erent learning rates for the tasks assigned to di erent stations will distort the work allocation of even the perfectly balanced lines.
Q3. What are the modi® cations considered for the SMD problem?
Stochasticity of the task times, requirement of task groupings according to task skill levels, andmixed-model situations are among the modi® cations considered.
Q4. Why have they concluded that the MMD problem is of more theoretical than practical interest?
Due to the excessive number of constraints and variables, they have concluded that theformulation is of more theoretical than practical interest.
Q5. What is the performance of the procedure?
The performance of the procedure depends on the setting of various parameters, e.g. the rate of cooling and the number of con® guration changes.
Q6. What is the potential of the hybrid line concept?
The `hybrid line’ concept suggested by Lau and Shtub (1987) seems to have the potential of generating designs with lower total costs and needs to be further studied.
Q7. What are the four sets of problems that are generated for comparison purposes?
Four sets of problems are generated for comparison purposes: the ® rst set consists of sixty 50-task and sixty 100-task problems with di erent order strengths, cycle times and task times.
Q8. How many iterations have the results above been achieved?
The authors claim that the results above have been achieved with 500 iterations; if it had been with more iterations, more than 14 problems would have outperformed.
Q9. What is the mean duration of a task?
The mean duration time of a task is assumed to be a non-increasing discrete function of the number of workers at the station to which the task is assigned.
Q10. What is the second group of heuristic procedures?
The second group consists of heuristic procedures that utilize principles or devices that contribute to the reduction of search in the problem-solving activity at a cost of not guaranteeing the optimal solution.
Q11. What is the procedure used to determine the proportional occurrences of the model variations?
Past dataare utilized to determine the proportional occurrences of the model variations, which form the weight factor to be used for calculating ¹is and s 2 i s.
Q12. What is the motivation for developing heuristic procedures?
Kim and Park (1995) state that another motivation to develop heuristic procedures is that the task times utilized in these procedures are usually rough estimates which do not account for the variability between workers and throughout time; thus, obtaining a g̀ood’ solution rather than the optimal one may be acceptable to the practitioners.