Convergence analysis of an Inexact Infeasible Interior Point method for Semidefinite Programming

In this paper we present an extension to SDP of the well known infeasible Interior Point method for linear programming of Kojima,Megiddo and Mizuno (A primal-dual infeasible-interior-point algorithm for Linear Programming, Math. Progr., 1993). The extension developed here allows the use of inexact search directions; i.e., the linear systems defining the search directions can be solved with an accuracy that increases as the solution is approached. A convergence analysis is carried out and the global convergence of the method is prove

On affine scaling inexact dogleg methods for bound-constrained nonlinear systems

Within the framework of affine scaling trust-region methods for bound constrained problems, we discuss the use of a inexact dogleg method as a tool for simultaneously handling the trust-region and the bound constraints while seeking for an approximate minimizer of the model. Focusing on bound-constrained systems of nonlinear equations, an inexact affine scaling method for large scale problems, employing the inexact dogleg procedure, is described. Global convergence results are established without any Lipschitz assumption on the Jacobian matrix, and locally fast convergence is shown under standard assumptions. Convergence analysis is performed without specifying the scaling matrix used to handle the bounds, and a rather general class of scaling matrices is allowed in actual algorithms. Numerical results showing the performance of the method are also given

Towards deliberative and pragmatic co-management:a comparison between inshore fisheries authorities in England and Scotland

In seeking to answer the question ‘who should be included in fisheries co-management?’, a constructive critique of the existing co-management literature is provided by filling the gaps of Habermas’s deliberative theory of democracy with Dewey’s pragmatism. Three conditions for ensuring democratic co-management are extrapolated from the theories: actors’ authority over decision making (empowerment), actors’ diversity (membership), and the right to self-nomination (procedures for external inclusion). The theoretical insights developed are supported with two examples of co-management institutions for inshore fisheries in the UK: Scottish Inshore Fisheries Groups (IFGs) and English Inshore Fisheries Conservation Authorities (IFCAs)

Eficácia da ventilação não invasiva nos grandes prematuros com síndrome de dificuldade respiratória: uma revisão bibliográfica

Projeto de Graduação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Licenciada em FisioterapiaObjetivo: Averiguar o papel da ventilação não invasiva (VNI) nos grandes prematuros (idade gestacional <34 semanas) com síndrome de dificuldade respiratória (SDR). Metodologia: Pesquisa computorizada nas bases de dados PubMed e PEDro para identificar estudos randomizados controlados que avaliam a eficácia da VNI nos grandes prematuros com SDR. Resultados: Nesta revisão foram incluídos 10 estudos envolvendo 840 lactentes, com classificação metodológica media de 6.2 em 10 na escala de Physiotherapy Evidence Database (PEDro), dos quais 1 compara o Continuous Positive Airway Pressure (CPAP) com a ventilação convencional contínua, 3 comparam o CPAP com o Nasal Intermittent Positive Pressure Ventilation (NIPPV), 2 comparam o CPAP com o Bi-level Positive Airway Pressure (BiPAP) e 4 comparam a eficácia do CPAP segundo os fluxos aplicados. Conclusão: Os estudos incluídos nesta revisão sugerem que o CPAP é eficaz, mas existem outras técnicas de VNI como a NIPPV que podem ser mais eficazes, mas que não são muito aplicadas porque ainda não são bem conhecidas. Sugere-se mais estudos sobre estas modalidades para provar a eficácia das outras técnicas de VNI.Objective: To determine the role of non-invasive ventilation (NIV) in very preterm (gestational age <34 weeks) with respiratory distress syndrome (RDS). Methodology: Research computerized on databases PubMed and PEDro to identify randomized controlled studies that evaluate the effectiveness of NIV in very preterm with RDS. Results: In this review were included 10 studies involving 840 babies, with methodology classification of 6.2 on the Physiotherapy Evidence Database Scale (PEDro). From that, 1 study compares the Continuous Positive Airway Pressure (CPAP) with the conventional mechanical ventilation, 3 studies compare the CPAP with the Nasal Intermittent Positive Pressure Ventilation (NIPPV), 2 studies compare CPAP with the Bi-level Positive Airway Pressure (BiPAP) and 4 compare the effectiveness of CPAP according to the flows applicated. Conclusion: The reviews suggest that the CPAP is effective, but there are other more NIV techniques like a NIPPV that can be more effective, but are not very used because they are not yet well known. To provide a better proof of effectiveness of the other NIV techniques, more studies are needed on the modalities.N/

A PDE-constrained optimization formulation for discrete fracture network flows

We investigate a new numerical approach for the computation of the 3D flow in a discrete fracture network that does not require a conforming discretization of partial differential equations on complex 3D systems of planar fractures. The discretization within each fracture is performed independently of the discretization of the other fractures and of their intersections. Independent meshing process within each fracture is a very important issue for practical large scale simulations making easier mesh generation. Some numerical simulations are given to show the viability of the method. The resulting approach can be naturally parallelized for dealing with systems with a huge number of fractures

Early warning monitoring of natural and engineered slopes with Ground-Based Synthetic Aperture Radar

The first application of ground-based interferometric synthetic-aperture radar (GBInSAR) for slope monitoring dates back 13 years. Today, GBInSAR is used internationally as a leading-edge tool for near-real-time monitoring of surface slope movements in landslides and open pit mines. The success of the technology relies mainly on its ability to measure slope movements rapidly with sub- millimetric accuracy over wide areas and in almost any weather conditions. In recent years, GBInSAR has experienced significant improvements, due to the development of more advanced radar techniques in terms of both data processing and sensor performance. These improvements have led to widespread diffusion of the technology for early warning monitoring of slopes in both civil and mining applications. The main technical features of modern SAR technology for slope monitoring are discussed in this paper. A comparative analysis with other monitoring technologies is also presented along with some recent examples of successful slope monitorin

Hybrid Newton-type method for a class of semismooth equations

In this paper, we present a hybrid method for the solution of a class of composite semismooth equations encountered frequently in applications. The method is obtained by combining a generalized finite-difference Newton method to an inexpensive direct search method. We prove that, under standard assumptions, the method is globally convergent with a local rate of convergence which is superlinear or quadratic. We report also several numerical results obtained applying the method to suitable reformulations of well-known nonlinear complementarity problem

A hybrid method for hydrodynamic-kinetic flow - Part I -A particle-gridmethod for reducing stochastic noise in kinetic regimes

In this work we present a hybrid particle-grid Monte Carlo method for the Boltzmann equation, which is characterized by a significant reduction of the stochastic noise in the kinetic regime. The hybrid method is based on a first order splitting in time to separate the transport from the relaxation step. The transport step is solved by a deterministic scheme, while a hybrid DSMC-based method is used to solve the collision step. Such a hybrid scheme is based on splitting the solution in a collisional and a non-collisional part at the beginning of the collision step, and the DSMC method is used to solve the relaxation step for the collisional part of the solution only. This is accomplished by sampling only the fraction of particles candidate for collisions from the collisional part of the solution, performing collisions as in a standard DSMC method, and then projecting the particles back onto a velocity grid to compute a piecewise constant reconstruction for the collisional part of the solution. The latter is added to a piecewise constant reconstruction of the non-collisional part of the solution, which in fact remains unchanged during the relaxation step. Numerical results show that the stochastic noise is significantly reduced at large Knudsen numbers with respect to the standard DSMC method. Indeed in this algorithm, the particle scheme is applied only on the collisional part of the solution, so only this fraction of the solution is affected by stochastic fluctuations. But since the collisional part of the solution reduces as the Knudsen number increases, stochastic noise reduces as well at large Knudsen number

Towards an ultra efficient kinetic scheme. Part I: basics on the BGK equation

In this paper we present a new ultra efficient numerical method for solving kinetic equations. In this preliminary work, we present the scheme in the case of the BGK relaxation operator. The scheme, being based on a splitting technique between transport and collision, can be easily extended to other collisional operators as the Boltzmann collision integral or to other kinetic equations such as the Vlasov equation. The key idea, on which the method relies, is to solve the collision part on a grid and then to solve exactly the transport linear part by following the characteristics backward in time. The main difference between the method proposed and semi-Lagrangian methods is that here we do not need to reconstruct the distribution function at each time step. This allows to tremendously reduce the computational cost of the method and it permits for the first time, to the author's knowledge, to compute solutions of full six dimensional kinetic equations on a single processor laptop machine. Numerical examples, up to the full three dimensional case, are presented which validate the method and assess its efficiency in 1D, 2D and 3D