In 1986 Warga proposed a “weak” relaxation procedure applicable to fully nonlinear problems with delays in the control variables and showed that the resulting relaxed problem has a solution. However, in the event of commensurate delays, several examples were found for which weakly relaxed controls cannot be approximated with original controls, so that this extension fails to be “proper.” Althou...

We consider general, typically nonconvex, Quadratic Programming Problems. The Semi-deenite relaxation proposed by Shor provides bounds on the optimal solution, but it does not always provide suuciently strong bounds if linear constraints are also involved. To get rid of the linear side-constraints, another, stronger convex relaxation is derived. This relaxation uses copositive matrices. Special...

This paper presents a hybrid tabu search strategy for lot sizing problems. This strategy allows the exploitation of the quality of the well-known relax-and-fix heuristic, inside a tabu search framework which enforces diversity. The computational results show an advantage of this strategy when compared to a version of the relax-and-fix heuristic and to time constrained branch-and-bound.

Background: Lack of hamstrings flexibility has been reported to be one of the most important factors contributing to hamstrings injury during high-speed and high-intensity exercise. Active stretching of hamstrings has been found to be more beneficial than passive stretching after 4 weeks. Objective: To compare the effects of two active stretching techniquesmodified hold relax technique of PNF a...

[Purpose] The aim of present study was to compare the effectiveness of modified hold-relax stretching and static stretching in improving the hamstring muscle flexibility. [Subjects and Methods] Forty-five male subjects with hamstring tightness were included in this study. The subjects were randomly placed into three groups: the modified hold-relax stretching, static stretching and control group...