Sharif Digital Repository

This study deals with the heuristic solution of flexible flow shop scheduling problems with unrelated parallel machines. No preemption of jobs is allowed. As an objective function, this paper considers the minimization of total tardiness. As a first step to propose solution, two different mixed integer mathematical models are developed which tackle the problem at hand. The problem is NP-hard and thus the developed mathematical program can only solve problem instances for small sizes in a reasonable amount of time. The next step is to build heuristics which can provide feasible solutions in polynomial time for larger problem instances. Then in the study develops a constructive heuristic for... 

As application demands for online convex optimization accelerate, the need for design-ing new methods that simultaneously cover a large class of convex functions and im-pose the lowest possible regret is highly rising. Known online optimization methods usually perform well only in specific settings, e.g., specific parameters such as the diam-eter of decision space, Lipschitz constant, and strong convexity coefficient, where their performance depends highly on the geometry of the decision space and cost functions. However, in practice, the lack of such geometric information leads to confusion in using the appropriate algorithm. To address these issues, some adaptive methods have been proposed... 

This research focuses on determining the optimal base shear coefficient for the design of conventional steel buildings based on the minimization of lifecycle cost (LCC) and associated uncertainties throughout the service life of the building. Current seismic design codes are calibrated based on engineering judgment, acceptable societal risk, or past earthquake experiences. However, technical literature has shown that such calibration does not lead to a design that optimally balances construction costs and seismic damage. As a solution, lifecycle cost-based calibration has been proposed. In this study, the optimal range of the base shear coefficient is determined by minimizing the expected...