811 research outputs found
Innovation public policy—the case of Portugal
Innovation public policy has an essential role in influencing the competitive capacity of companies and is strongly asso-ciated with their ability to innovate and the way they are organized. As important as the technological organization of work is the social dimension, namely, involvement, participation, and commitment of the workforce, as these are, par excellence, factors that contribute to creating added value and differentiation for companies. In this sense, the concept of innovation depends on an integrated vision between the human dimension and the other multiple dimensions that innovation can assume. Public policies, besides the goal of creating a more modern and competitive business and industrial context, also are focused on the development of the workforce, not only in digital competences but also in soft skills. This type of skill contributes to creating a more innovative context and a culture of innovation. This article’s goal is to make a global overview of innovation and the public policies to promote the modernization of companies and influence the way they contribute to economic growth.info:eu-repo/semantics/publishedVersio
An application of semi-infinite programming to air pollution control
Environment issues are more then ever important in a modern society.
Complying with stricter legal thresholds on pollution emissions raises an important economic issue. This talk presents some ideas in the use of optimization tools to help in the planning and control of non mobile pollution sources.
We assume a Gaussian plume model where a plume rise and weather stabilities classes are considered.
Three main semi-infinite programming formulations are described and numerical results are shown
Optimização e controlo da poluição atmosférica
Alguns problemas de controlo da poluição atmosférica podem ser formulados
como problemas de programação semi-infinita (PSI). Estas formulações, das quais
descrevemos três abordagens, permitem que as instalações fabris cumpram a legislação da poluição atmosférica enquanto que o impacto económico é minimizado. As mesmas ferramentas da programação matemática podem também ser usadas pelas autoridades competentes no sentido de verificar que os limites impostos por lei são cumpridos, através do planeamento da localização dos postos de amostragem/controlo. A primeira das formulações consiste em optimizar um
determinado objectivo enquanto que o nÃvel de poluição atmosférica é mantido
abaixo de um valor de referência. A segunda consiste no cálculo da poluição
atmosférica máxima atingida numa determinada região e a terceira considera um
problemas de redução da poluição. Estas formulações permitem obter os melhores
parâmetros de controlo e as posições onde os valores máximos da poluição são
atingidos, posições essas que correspondem ao melhor posicionamento dos postos
de amostragem/controlo.
As abordagens propostas são ilustradas com quatro problemas académicos. As ferramentas actualmente existentes apoiam a PSI desde a modelação do problema até à sua resolução. A linguagem de modelação (SIP)AMPL foi usada para codificar os problemas propostos e o solver NSIPS foi empregue na resolução dos mesmos
Optimal control of fed-batch processes with particle swarm optimization
Optimal control problems appear in several engineering fields. These problems are often described by sets of nonlinear differential and algebraic equations, usually subject to constraints in the state and control variables. Some bioprocess optimal control problems are revisited and a numerical approach to its solution is introduced.
The numerical procedure used to solve the problems takes advantage of the well know modeling AMPL language, providing an external dynamic library that solve the nonlinear differential equations. The optimal control problem as generally presented belongs to the class of semi-infinite programming (SIP) problems. A transformation of the SIP problem results in a nonlinear optimization problem (NLP) that can be address by off-the-shelf optimization software. The NLP formulation results in nondifferentiable optimization problems were the global solution is mostly desirable. We apply a particle swarm optimization strategy implemented in the MLOCPSOA [13] solver. Particle swarm optimization (PSO) is a stochastic technique that mimics the social behavior of a swarm
Semi-infinite air pollution control problems
Semi-infinite programming (SIP) problems arise in many engineering areas. Robot trajectory
planning and optimal signal sets are two fine examples. Air pollution abatement problems, which
are linear SIP problems, were proposed in the seventies by Gustafson and Kortanek [Analytical
properties of some multiple-source urban diffusion models, Environment and Planning 4, pp. 31-
41, 1972].
Recent available tools for non-linear SIP allow the formulation of more general air control
problems, namely the optimum stack design.
In the air control SIP problem an objective function is to be optimised (minimum stack height or
minimum cleaning costs), where the air pollution, at ground level, is kept bellow a given
threshold. A Gaussian model is used to provide estimates of air pollution in a region where mean
weather conditions are assumed.
In this talk, we present three formulated air pollution control problems coded in the (SIP)AMPL
modelling language and numerical results obtained with the discretization method of the NSIPS
solver
Air pollution control with semi-infinite programming
Air pollution control problems can be formulated as a semi-infinite
programming (SIP) problem and we describe three main approaches.
The first consists in optimizing an objective function while the pollution
level in a given region is kept bellow a given threshold. In the second
approach the maximum pollution level in a given region is computed and
in the third an air pollution abatement problem is considered. These
formulation allow to obtain the best control parameters and the maxima
pollution positions, where the sampling stations should be placed.
To illustrate this idea, the (SIP)AMPL modeling language was used
to code three academic problems. The SIPAMPL software package includes
an interface to connect AMPL to any SIP solver, in particular to
the NSIPS solver. Numerical results are shown with the discretization
method, implemented in the NSIPS solver and it proved to be efficient
in solving the proposed problems
On the error of calculation of heat gains through walls by methods using constant decrement factor and time lag values
A transient heat transfer model was developed to numerically predict the thermal behaviour of the external walls of a room under realistic outdoor conditions. The excitation is not simply sinusoidal even though it is considered to have daily periodicity. The numerical model is based on the finite difference method and handles one-dimensional heat conduction through multilayered walls. The boundary condition at the outer surface of the wall is described with the sol-air temperature concept. The temperatures of indoor air and of other internal surfaces in the room are assumed to be equal and constant.
The numerical results were used to calculate values of the decrement factor and time lag of several walls. The calculation followed two methods found in literature, in which these parameters are assumed constant, distinguished by the temperature evolution used: the sol-air or the wall's outer surface. Additionally, the inner surface temperature is used in both methods. The walls investigated range from low to high mass construction, face towards various directions and have light or dark coloured sunlit outer surfaces.
The heat fluxes at the inner surface of the walls predicted by numerical modelling and estimated by the simplified methods are compared in detail to conclude on the validity of these simplified methods. As a by-product it is also possible to conclude on the dependence of the decrement factor and of the time lag on the outer surface colour and on the orientation of different types of walls. The results show that both simplified methods have poor accuracy in a significant number of cases. Also, it was found that the wall's azimuth significantly affects the time lag
The precision of propex Pixi with different instruments and coronal preflaring procedures
Objective:This study aimed to evaluate the influence of the instrument regarding the apical fit and type of the alloy and coronal preflaring procedures in the accuracy of Propex Pixi.Methods: A total of 40 extracted human single-rooted permanent teeth with apical diameters of 200 mu m were selected. A #10 K-file was inserted in the root canal until its end could be observed by a dental microscope to obtain the actual working length (WL). Electronic measurements were performed using Propex Pixi to the root apex ("0.0"). Different file alloys (stainless steel [SS] and nickel titanium [NiTi]) and sizes (#10, #15, and #20) were used before and after coronal flaring. Statistical analysis was performed by a factorial analysis of variance (P <= 0.05).Results: Results showed that the measurements of electronic length (EL) were closer to the actual working length (WL) after coronal flaring (P<0.05). A significant intraclass correlation was observed between EL and WL. In addition, results showed no significant differences between files with different sizes or alloys.Conclusion: Under the conditions of this study, Propex Pixi demonstrated adequate precision. Its accuracy was enhanced by coronal preflaring procedures regardless of the instrument type used (SS or NiTi) and the apical fit.- (undefined
Avaliação da qualidade de tratamentos endodônticos realizados por estudantes de Medicina Dentária
Objectives: To assess radiographically the technical quality of root fillings placed by undergraduate students at the Faculty of Dental Medicine of the University of Porto. Methods: The records of 318 patients were assessed, of which 225 radiographs of root canal fillings in single-rooted teeth were selected. The radiographs were examined using the VixWin Platinum v1.1 Imaging Software (Gendex, USA). The quality of root canal filling was graded as "acceptable" when both length and density were adequate. Procedural errors were registered. Chi-square tests were used for statistical analysis, considering a 0.05 significance level. Results: Root canal fillings were considered acceptable in 53.3% of the cases. There was a greater percentage of adequate density (70.7%) than adequate length (64%). There was a statistically significant association between the quality of the filling and the type of tooth, with maxillary anterior teeth presenting higher quality (p=0.027). The most common reason for inadequate length was short-filling (33%). There was a statistically significant relationship between the academic year and the density of the fillings (p=0.009). Overall procedural errors occurred in 3.6% of the cases, with the most common being ledge formation and apical transportation. Conclusions: The quality of root canal fillings in single-rooted teeth performed by junior dental students at the University of Porto was considered acceptable in 53.3% of cases.Objetivos: Avaliar radiograficamente a qualidade das obturações de tratamentos endodônticos realizados por estudantes do Mestrado Integrado da Faculdade de Medicina Dentária
da Universidade do Porto.
Métodos: Foram avaliados os registos de 318 pacientes, dos quais foram selecionadas
225 radiografias periapicais de dentes monorradiculares. As radiografias foram examinadas utilizando o software de imagem VixWin Platinum v1.1 (Gendex, EUA). A qualidade do tratamento endodôntico foi classificada como "aceitável" quando o comprimento e a densidade estavam adequados. Os erros iatrogénicos foram registados. O
teste qui-quadrado foi utilizado para análise estatÃstica, considerando um nÃvel de significância de 0,05.
Resultados: O tratamento endodôntico foi considerado aceitável em 53,3% dos casos. Houve
uma maior percentagem de densidade adequada (70,7%) do que comprimento adequado
(64%). Verificou-se uma associação estatisticamente significativa entre a qualidade da obturação e o tipo de dente, sendo os dentes anteriores superiores a apresentar maior qualidade (p = 0,027). A razão mais comum para o comprimento inadequado foram as obturações
curtas (33%). Verificou-se uma relação estatisticamente significativa entre o ano letivo e a
densidade da obturação (p = 0,009). Erros iatrogénicos ocorreram em 3,6% dos casos, sendo
os mais comuns a formação de degraus e o transporte apical.
Conclusões: A qualidade dos tratamentos endodônticos em dentes monorradiculares realizados por estudantes de Medicina Dentária da Universidade do Porto foi considerada aceitável em 53,3% dos casos.- (undefined
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