Given the increasing public awareness of environmental impacts, governments have made regulation on pollutants more stringent. Therefore, the Unit Commitment Problem (UCP), which traditionally minimizes the total production costs, needs to consider the pollutants emissions as another objective. This way, the UCP becomes a multiobjective problem with two competing objectives. The approach propos...

The current research deals with the exact solutions of nonlinear partial differential equations having two important difficulties, that is, coefficient singularities and stochastic function (white noise). There are four major contributions to contemporary research. One is mathematical analysis where explicit a priori estimates for existence constructed by Schauder’s fixed point theorem. Secondl...

Recent progress on string theory in curved spacetimes is reviewed. The string dynamics in cosmological and black hole spacetimes is investigated. The different methods available to solve the string equations of motion and constraints in curved spacetimes are described. That is, the string perturbation approach, the null string approach, the τ -expansion, and the construction of global solutions...

The paper presents a generalization of the Strength Pareto Evolutionary Algorithm 2 (SPEA2) and its application in selected well-known twoand threeobjective optimization benchmark problems. The proposed solution is referred to as our SPEA3. The generalization consists in the exchange of the environmental selection procedure in SPEA2 for a new original algorithm which aims to determine the final...

We present a method which enables exact solutions to be found for flat homogeneous and isotropic scalar-tensor cosmologies with an arbitrary ω(Φ) function and satisfying the general perfect fluid state equation P = (γ−1)ρc2. This method has been used to analyze a wide range of asymptotic analytical solutions at early and late times for different epochs in the cosmic history: false vacuum inflat...

In this paper we study the dynamical behaviour of a simple cosmological model defined by a spatially flat Robertson-Walker geometry, conformally coupled with a massive scalar field. We determine a Lyapunov-like function for the non-linear evolution equations. From this function we prove that all the stationary solutions are unstable. We also show that all initial conditions, different from the ...

This paper compares ant colony optimization (ACO) and evolutionary multi-objective optimization (EMO) for the weather avoidance in a free flight environment. The problem involves a number of potentially conflicting objectives such as minimizing deviations, weather avoidance, minimizing distance traveled and hard constraints like aircraft performance. Therefore, we modeled the problem as a multi...

This paper presents an optimization of photovoltaic water pumping system (PWPS) considering the reliability criteria and economic aspects. In this way loss of load probability (LLP) as reliability criteria and life cycle cost (LCC) as economic criteria are used to simulate the performance of the PWPS. The sizing of a photovoltaic pumping system means the sizing of the photovoltaic module number...

in oil industry, spontaneous imbibition is an important phenomenon in recovery from fractured reservoirs which can be defined as spontaneous uptake of a wetting fluid into a porous solid. spontaneous imbibition involves both cocurrent and countercurrent flows. when a matrix block is partially covered by water, oil recovery is dominated by cocurrent imbibition i.e. the production of non wetting ...