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Delay-dependent exponential stabilization of positive 2D switched state-delayed systems in the Roesser model

2014

This paper deals with the controller synthesis for a class of positive two-dimensional (2D) switched delay systems described by the Roesser model. This kind of systems has the property that the states take nonnegative values whenever the initial boundaries are nonnegative, some delay-dependent sufficient conditions for the exponential stability of positive 2D switched systems with state delays are given. Furthermore, the design of positive state feedback controller under which the resulting closed-loop system meets the requirements of positivity and exponential stability is presented in terms of linear matrix inequalities (LMIs). An example is included to illustrate the effectiveness of the…

A feedback view of behavioural distortions from perceived public service gaps at ‘street‐level’ policy implementation: The case of unintended outcome…

2020

This paper discusses the limitations and risks associated with the use of output-oriented measures to assess public school performance. In particular, it questions the capability of the performance measures set by external institutions, with respect to schools, to support sustainable educational outcomes. To this end, the ‘street-level bureaucracy’ theory is used in the paper as a basis to analyse the behavioural distortions generated by perceived public service gaps at school level policy implementation. Such unintended behavioural effects are often a major cause of disappointing outcomes when test-based accountability systems are adopted. In the second part of the paper, an insight model …

A NSGA Based Approach for Content Based Image Retrieval

2013

The purpose of CBIR Content Based Image Retrieval systems is to allow users to retrieve pictures related to a semantic concept of their interest, when no other information but the images themselves is available. Commonly, a series of images are presented to the user, who judges on their relevance. Several different models have been proposed to help the construction of interactive systems based on relevance feedback. Some of these models consider that an optimal query point exists, and focus on adapting the similarity measure and moving the query point so that it appears close to the relevant results and far from those which are non-relevant. This implies a strong causality between the low l…

An interactive evolutionary approach for content based image retrieval

2009

Content Based Image Retrieval (CBIR) systems aim to provide a means to find pictures in large repositories without using any other information except its contents usually as low-level descriptors. Since these descriptors do not exactly match the high level semantics of the image, assessing perceptual similarity between two pictures using only their feature vectors is not a trivial task. In fact, the ability of a system to induce high level semantic concepts from the feature vector of an image is one of the aspects which most influences its performance. This paper describes a CBIR algorithm which combines relevance feedback, evolutionary computation concepts and ad-hoc strategies in an attem…

Variable Neighborhood Search for the Vertex Separation Problem

2012

The vertex separation problem belongs to a family of optimization problems in which the objective is to nd the best separator of vertices or edges in a generic graph. This optimization problem is strongly related to other well-known graph problems; such as the Path-Width, the Node Search Number or the Interval Thickness, among others. All of these optimization problems are NP-hard and have practical applications in VLSI, computer language compiler design or graph drawing. Up to know, they have been generally tackled with exact approaches, presenting polynomial-time algorithms to obtain the optimal solution for speci c types of graphs. However, in spite of their practical applications, these…

Selective area vapor-phase epitaxy and structural properties of Hg1 − xCdxTe on sapphire

1997

Selective area (SA) Hg1 − xCdxTesapphire layers have been grown using the recently developed technique of the vapor-phase epitaxy (VPE) of Hg1 − xCdxTe layers on CdTesapphire heteroepitaxial substrates (HS), which we have called “VPE on HS technique” (Sochinskii et al., J. Crystal Growth 149 (1995) 35; 161 (1996) 195). First, planar CdTe (1 1 1) 5–7 μm thick layers were grown on sapphire (0 0 0 1) wafers by metalorganic vapor-phase epitaxy (MOVPE) at 340°C for 1–2.5 h using dimethylcadmium and di-isopropyltellurium as precursors. Second, CdTe/sapphire mesas were formed using standard photolithography in the form of alternating parallel linear arrays consisting of 500 × 70 μm2 elements. Thir…

First Annelated Azaphosphole-Ferrocenes: Synthetic Pathways and Structures

2012

The first annelated bis- and mono-3H-1,3-azaphosphole ferrocene sandwich compounds have been synthesized from aminoferrocenes, and their X-ray structures are compared to those of their selenide-protected P═Se analogues, showing net discrepancies both in metallocene backbone conformation and in fused-ring planarity.

Input-output feedback linearizing control of linear induction motor taking into consideration the end-effects. Part I: Theoretical analysis

2015

Abstract This first part of a paper, divided into two parts, deals with the theoretical formulation of the input–output feedback linearization (FL) control technique as to be applied to linear induction motors (LIMs). Linear induction motors, differently from rotating induction motors (RIMs), present other strong non-linearities caused by the so-called dynamic end effects, leading to a space-vector model with time-varying inductance and resistance terms and an additional braking force term. This paper, starting from a dynamic model of the LIM taking into consideration its dynamic end effects, previously developed by the same authors, defines a feedback linearization (FL) technique suited fo…

Input-Output Feedback Linearizing Control of Linear Induction Motor Taking into Consideration the End-Effects. Part II: Simulation and Experimental R…

2015

This is the second part of a paper, divided in two parts, dealing with the application of the input–output feedback linearization (FL) control technique to linear induction motors (LIMs). The first part has treated the theoretical formulation of the input–output feedback linearization control technique as to be applied to linear induction motors. This second part describes the set of tests, both in numerical simulations and experiments, performed to assess the validity of the control technique. In particular, it addresses the issues of the sensitivity of the FL control versus the LIM electrical parameters’ variations and the improvements achievable by considering the LIM dynamic end effects…

Institutions and Deontic Powers: Some Comments on the Tuomela-Searle Debate

In this talk I will analyze Tuomela’s theory of institutions and the most recent debate with Searle over the issue of whether institutions conceptually involve the creation and distribution of deontic powers. By way of analyzing Tuomela and Searle’s reciprocal criticisms, I conclude that Tuomela does not give us sufficient reasons to give up Searle’s thesis that institutions always involve deontic powers, but I also argue that it is necessary to go beyond Searle’s recent speech act-centered explanation of human sociality. More specifically, moving along the lines of Di Lorenzo’s view of constitutive rules as built into the logical and pragmatic structure of human activities, and making use …