Problem of Hydroelectric Resources Management: Numerical Approach

In this work we analyze an optimal control problem for a system of two hydroelectric power stations in cascade with reversible turbines. The objective is to optimize the profit of power production while respecting the system’s restrictions. Some of these restrictions translate into state constraints and the cost function is nonconvex. This increases the complexity of the optimal control problem. The problem is solved numerically and two different approaches are adopted. These approaches focus on global optimization techniques (Chen-Burer algorithm) and on a projection estimation refinement method (PERmethod). PERmethod is used as a technique to reduce the dimension of the problem. Results and execution time of the two procedures are compared.

A novel two-stage discrete crack method based on the screened Poisson equation and local mesh refinement

We propose an alternative crack propagation algo- rithm which effectively circumvents the variable transfer procedure adopted with classical mesh adaptation algo- rithms. The present alternative consists of two stages: a mesh-creation stage where a local damage model is employed with the objective of defining a crack-conforming mesh and a subsequent analysis stage with a localization limiter in the form of a modified screened Poisson equation which is exempt of crack path calculations. In the second stage, the crack naturally occurs within the refined region. A staggered scheme for standard equilibrium and screened Poisson equa- tions is used in this second stage. Element subdivision is based on edge split operations using a constitutive quantity (damage). To assess the robustness and accuracy of this algo- rithm, we use five quasi-brittle benchmarks, all successfully solved.

Historical landmarks of decent work

Structured Abstract Purpose: this article systemizes the main historical milestones which led to the current concept of decent work and presents some implications for business. Approach: after presenting the scenario which gives a special meaning and importance to decent work, the historical landmarks are systematized until the definition of the Decent Work Agenda. Findings: Decent work is a concept that has evolved since the ILO Foundation in 1919 and had several important steps throughout its development: Philadelphia Declaration in 1944, ILO constitution update in 1946, Universal Declaration of Human Rights in 1948, Human Development Report, first edition in 1990, World Summit for Social Development in 1995, ILO Declaration on Fundamental Principles and Rights at Work in 1998, World Economic Forum in 1999, Global Compact in 2000, United Nations Millennium Declaration in 2000, ILO Declaration on Social Justice for a Fair Globalization in 2008, Global Jobs Compact in 2009, and inclusion in the 2030 Agenda for Sustainable Development. Throughout this development we can witness the refinement and operationalization of the concept, its institutionalization and its spread at political level, at least as an intention. Practical implications: the business area is a privileged forum to turn policies into practices and some examples are provided. Value: although decent work emerged in a very different social and economic scenario from the present time, it is claimed to be even more topical and relevant for the development of business and society today.