teleworking as an innovative way has many benefits in governmental, organizational and individual levels, but it faced with different variables in plan and implementation which is caused to low acceptance rate in organizations. by identifying and controlling these variables, managers and decision-makers can use teleworking programs in their organizations. the aim of this study is to investigate...

A constraint is a limitation or a restriction that poses a threat to the performance and efficiency of a system. This paper presented a tactical review approach to production constraints modeling. It discussed the theory of constraints (TOC) as a thinking process and continuous improvement strategy to curtail constraints in other to constantly increase the performance and efficiency of a system...

we design a two-stage scheme to consider trajectory planning problem of two mobile manipulators for cooperative transportation of a rigid body in presence of static obstacles. within the first stage, regarding the static obstacles we develop a method that searches the workspace for the shortest possible path between start and goal configurations by constructing a graph on a portion of the confi...

The effect of symmetry-breaking constraints is often evaluated empirically. In order to understand which symmetric configurations are removed by a set of constraints, we have to understand the underlying structure of the symmetry group in concern. A class of symmetry that frequently occurs in constraint programming is the row and column symmetries of a matrix model. In this paper, we study thes...

A new smoothing approach based on entropic regularization is proposed for solving a mathematical program with equilibrium constraints (MPEC). With some known smoothing properties of the entropy function and keeping real practice in mind, we reformulate an MPEC problem as a smooth nonlinear programming problem. In this way, a di9cult MPEC problem becomes solvable by using available nonlinear opt...

Complete row and column symmetry breaking in constraint satisfaction problems using the lex leader method is generally prohibitively costly. Double lex, which is derived from lex leader, is commonly used in practice as an incomplete symmetry-breaking method for row and column symmetries. This technique uses a row-wise ordering to construct the lex leader. For this reason, it is generally counte...

The paper studies three classes of optimization problems with bilevel structure including mathematical programs with equilibrium constraints (MPEC) and semiinfinite problems (SIP). The main goal of the paper is to provide results which establish the existence of feasible points of the problems. These results are based on the so-called KKM Lemma. We are also interested in the convexity propertie...

A previous paper showed that adding binary symmetry breaking constraints to a model can degrade local search performance. This paper shows that even unary constraints are not necessarily beneficial because they can transform solutions into local minima. Furthermore, performance can be improved by the reverse of symmetry breaking: using a supersymmetric model with extra symmetry. Some improved r...

We identify an important class of symmetries in constraint programming, arising from matrices of decision variables where rows and columns can be swapped. Whilst lexicographically ordering the rows (columns) breaks all the row (column) symmetries, lexicographically ordering both the rows and the columns fails to break all the compositions of the row and column symmetries. Nevertheless, our expe...

This paper presents a branch-and-bound algorithm for minimizing the sum of a convex function in x, a convex function in y and a bilinear term in x andy over a closed set. Such an objective function is called biconvex with biconcave functions similarly defined. The feasible region of this model permits joint constraints in x and y to be expressed. The bilinear programming problem becomes a speci...