Two-objective Optimization Problem Research Articles

Variational criterion for dissipative structures dominated by coupled mechanisms

By analyzing the similarity between the viscosity-inertia compromise for single fluid in turbulent pipe flow and the particle-fluid compromise in gas-solid fluidization, it is deduced that the variational criterion for dissipative structures dominated jointly by two sub-mechanisms (for instance, viscous effect and inertial effect in turbulent flow; particle movement and fluid movement in fluidization) could be physically expressed as mutually constrained extremum between the individual extremum tendencies of the sub-mechanisms, and could thus be mathematically formulated as a two-objective optimization problem.

On the Tradeoff Control to Concurrent Product and Process Design

Concurrent product and process design may be modeled as a generalized two-objective optimization problem. The first objective characterizes "product design" with. the aim of best enhancing product functionality, while the second objective corresponds to "process de sign" with the aim of minimizing overall manufacturing costs. However, these performing goals may be mutually conflicting in arriving con currently at their respective optima, therefore, design tradeoffs must be settled in order to achieve a best compromise design. In this work, an adaptive tradeoff parameter, λ(0 ≤ λ ≤ 1.0), is introduced to adaptively control the progressive design tradeoffs between the two per forming goals by calibrating the tradeoff parameter λ over the interval of 0 to 1.0 A fuzzy control scheme is proposed to control the iteration-based design tradeoffs with concurrent design progression for an optimal compromise selttlement in design. Three design models are presented to accommodate different tradeoff scenarios in concurrent design. The proposed approach is illustrated through the case study of a welded beam design.

Reliability and wirability optimizations for module placement on a convectively cooled printed wiring board

Traditionally, printed wiring board (PWB) placement techniques have been focused on improving wirability. However, with the increasing demand for highly reliable densely packaged electronic equipment, considerable attention has been focused on the methods which can improve reliability at higher packaging levels. This paper considers both reliability and wirability together for arranging electronic modules on a convectively cooled printed wiring board. An ordered best-first search algorithm is presented for the two-objective optimization problem. The algorithm always examines the “successors” of the “most promising” node in the search tree. The results show that the system failure rate can be greatly reduced without deteriorating the wirability. Furthermore, the first obtained solution which satisfies the bound on wirability was demonstrated to have very high quality in system failure rate. Thus, the method can be used for large-sized problems if the solutions needed are only nearly optimum. On the other hand, for small-sized problems, the Pareto optimal solutions can be obtained by the method.