Optimal power flow (OPF) over power transmission networks poses challenging large-scale nonlinear optimization problems, which involve a large number of quadratic equality and indefinite quadratic inequality constraints. These computationally intractable constraints are often expressed by linear constraints plus matrix additional rank-one constraints on the outer products of the voltage vectors...

In the literature, Markowitz’s mean-variance model and its variants have been shown to yield portfolios that put excessive weights on only a few assets. Many diversity constraints were proposed and added to these models to avoid such overly concentrated portfolios. However, since these diversity constraints are formulated differently, it becomes difficult to compare them and study their relatio...

We analyze the performance of the greedy algorithm, and also a discrete semi-gradient based algorithm, for maximizing the sum of a suBmodular and suPermodular (BP) function (both of which are non-negative monotone non-decreasing) under two types of constraints, either a cardinality constraint or p ≥ 1 matroid independence constraints. These problems occur naturally in several real-world applica...

We show that two simple constraints, when applied to short user queries (on the order of 5{10 words) can yield precision scores comparable to or better than those achieved using long queries (50{85 words) at low document cuto levels. These constraints are meant to detect documents that have subtopic passages that includes the most important components of the query. The constraints are: (i) a si...

the aim of this study is to carry out an empirical study of constraint factors in recreational sporting activities. more specifically it tests the model of constraints (intra-personal, interpersonal, and structural), as proposed by crawford et al. (1991), and its relationship with actual participation levels in specific recreational sports activities in iran. although there is a growing body o...

In recent years, significant research efforts have been devoted to the optimal planning of power systems. Substation Expansion Planning (SEP) as a sub-system of power system planning consists of finding the most economical solution with the optimal location and size of future substations and/or feeders to meet the future load demand. The large number of design variables and combination of discr...