The global competitive environment and the growing demand for personalised products have increased the interest of companies in producing similar product models on the same assembly line. Companies are forced to make significant structural changes to rapidly respond to diversified demands and convert their existing single-model lines into mixed-model lines in order to avoid unnecessary new line construction cost for each new product model. Mixed-model assembly lines play a key role in increasing productivity without compromising quality for manufacturing enterprises. The literature is extensive on assembling small-sized products in an intermixed sequence and assembling large-sized products in large volumes on single-model lines. However, a mixed-model parallel two-sided line system, where two or more similar products or similar models of a large-sized product are assembled on each of the parallel two-sided lines in an intermixed sequence, has not been of interest to academia so far. Moreover, taking model sequencing problem into consideration on a mixed-model parallel two-sided line system is a novel research topic in this domain. Within this context, the problem of simultaneous balancing and sequencing of mixed-model parallel two-sided lines is defined and described using illustrative examples for the first time in the literature. The mathematical model of the problem is also developed to exhibit the main characteristics of the problem and to explore the logic underlying the algorithms developed. The benefits of utilising multi-line stations between two adjacent lines are discussed and numerical examples are provided. An agent-based ant colony optimisation algorithm (called ABACO) is developed to obtain a generic solution that conforms to any model sequence and it is enhanced step-by-step to increase the quality of the solutions obtained. Then, the algorithm is modified with the integration of a model sequencing procedure (where the modified version is called ABACO/S) to balance lines by tracking the product model changes on each workstation in a complex production environment where each of the parallel lines may a have different cycle time. Finally, a genetic algorithm based model sequencing mechanism is integrated to the algorithm to increase the robustness of the obtained solutions. Computational tests are performed using test cases to observe the performances of the developed algorithms. Statistical tests are conducted through obtained results and test results establish that balancing mixed-model parallel two-sided lines together has a significant effect on the sought performance measures (a weighted summation of line length and the number of workstations) in comparison with balancing those lines separately. Another important finding of the research is that considering model sequencing problem along with the line balancing problem helps algorithm find better line balances with better performance measures. The results also indicate that the developed ABACO and ABACO/S algorithms outperform other test heuristics commonly used in the literature in solving various line balancing problems; and integrating a genetic algorithm based model sequencing mechanism into ABACO/S helps the algorithm find better solutions with less amount of computational effort.

Submitted by Maicon Juliano Schmidt (maicons) on 2015-03-25T13:29:38Z No. of bitstreams: 1 Vinícius Facchin Nonnenmacher.pdf: 4021302 bytes, checksum: 9217f078c1f2b43c4aaf240fdadbf2f0 (MD5) / Made available in DSpace on 2015-03-25T13:29:38Z (GMT). No. of bitstreams: 1 Vinícius Facchin Nonnenmacher.pdf: 4021302 bytes, checksum: 9217f078c1f2b43c4aaf240fdadbf2f0 (MD5) Previous issue date: 2012-01-31 / Nenhuma / Modelos computacionais vem ganhando espaço nas ciências sociais. Tanto porque eles permitem uma formalização mais precisa dos fenômenos sociais, quanto porque recriam comportamentos sociais com maior realismo. Um dos fenômenos mais característicos da sociedade é a formação de opinião de indivíduos dado uma determinada situação de escolha. Este trabalho propõe a formalização do fenômeno social da formação de opinião entre um grupo de atores onde só é possível assumir uma ou outra opinião (cenário dicotômico). Para isso, foi proposto uma abordagem computacional baseada em agentes para a simulação desse cenário com o objetivo de melhor entender esse processo. / Computer modeling has been gaining ground in the social sciences. Both because they allow a more accurate formalization of social phenomena, and because it recreates social behaviors with greater realism. One of the most characteristic phenomena of a society is the opinion formation of individuals as a given situation of choice. This paper proposes the formalization of social phenomenon of opinion formation between a group of actors where it can only take one or other opinion (dichotomous scenario). For this, we propose an agent-based computational approach to simulate this scenario in order to provide a better understanding of this process.