Fuzzy linguistic controllers applied to decouple control loop effects

A fuzzy linguistic controller has been developed and implemented with the aim to cope with interactions between control loops due to coupling effects. To access the performance of the proposed approach several experiments have also been conducted using the classical PID controllers in the control loops. A mixing process has been used as test bed of all controllers experimented and the corresponding dynamic model has been derived. The successful results achieved with the fuzzy linguistic controllers suggests that they can be an alternative to classical controllers when in the presence of process plants where automatic control as to cope with coupling effects between control loops. © 2014 IEEE.

Comparison of internet usage habits in two generations of higher education students: a case study

Posters

Reducing the number of membership functions in linguistic variables

Dissertation presented at Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia in fulfilment of the requirements for the Masters degree in Mathematics and Applications, specialization in Actuarial Sciences, Statistics and Operations Research

Gender differences in internet usage habits: a case study in higher education

The usage of information and communication technologies has been growing among students and teachers. In order to improve the use of the Internet as a tool to support teaching and learning it is necessary to understand the Internet usage habits of students. Thus, a study was conducted with 1397 students from five schools of the Polytechnic of Porto. The data was collected through an online questionnaire abd was analized by age range, gender and scientific field. In this paper,gender differences are analyzed and presented in 3 dimensions: type of Internet usage, communication tools and the role of the Internet tools in education.

Differences in internet and LMS usage: a case study in higher education

The Internet plays an important role in higher education institutions where Learning Management Systems (LMS) occupies a main role in the eLearning realm. In this chapter we aim to characterize the Internet and LMS usage patterns and their role in the largest Portuguese Polytechnic Institute. The usage patterns were analyzed in two components: characterization of Internet usage and the role of Internet and LMS in education. Using a quantitative approach, the data analysis describes the differences between gender, age and scientific fields. The carried qualitative analysis allows a better understanding of students’ both motivations, opinions and suggestions of improvement. The outcome of this work is the presentation of the Portuguese students’ profile regarding Internet and LMS usage patterns. We expect that these results can be used to select the most suitable digital pedagogical processes and tools to be adopted regarding the learning process and most adequate LMS’s policies.

Coreceptor Usage by HIV-1 and HIV-2 Primary Isolates: The Relevance of CCR8 Chemokine Receptor as an Alternative Coreceptor

The human immunodeficiency virus replication cycle begins by sequential interactions between viral envelope glycoproteins with CD4 molecule and a member of the seven-transmembrane, G-protein-coupled, receptors' family (coreceptor). In this report we focused on the contribution of CCR8 as alternative coreceptor for HIV-1 and HIV-2 isolates. We found that this coreceptor was efficiently used not only by HIV-2 but particularly by HIV-1 isolates. We demonstrate that CXCR4 usage, either alone or together with CCR5 and/or CCR8, was more frequently observed in HIV-1 than in HIV-2 isolates. Directly related to this is the finding that the non-usage of CXCR4 is significantly more common in HIV-2 isolates; both features could be associated with the slower disease progression generally observed in HIV-2 infected patients. The ability of some viral isolates to use alternative coreceptors besides CCR5 and CXCR4 could further impact on the efficacy of entry inhibitor therapy and possibly also in HIV pathogenesis.

Smart metering consumer behavior study in the Republic of Ireland: Further analyses on the consumers’ electricity consumptions and usage perceptions

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

Protest attitudes and stated preferences: Evidence on scale usage heterogeneity

We contribute to the stated preference literature by addressing scale usage heterogeneity regarding how individuals answer attitudinal questions capturing lack of trust in institutions and fairness issues. Using a latent class model, we conduct a contingent valuation study to elicit the willingness-to-pay to preserve a recreational site. We find evidence that respondents within the same class, that is, with similar preferences and attitudes, interpret the Likert scale differently when answering the attitudinal questions. We identify different patterns of scale usage heterogeneity within and across classes and associate them with individual characteristics. Our approach contributes to better a understanding of individual behavior in the presence of protest attitudes.

Graph usage in financial reports: Evidence from Portuguese listed companies

When assessing investment options, investors focus on the graphs of annual reports, despite lack of auditing. If poorly constructed, graphs distort perceptions and lead to inaccurate decisions. This study examines graph usage in all the companies listed on Euronext Lisbon in 2013. The findings suggest that graphs are common in the annual reports of Portuguese companies and that, while there is no evidence of Selectivity Distortion, both Measurement and Orientation Distortions are pervasive. The study recommends the auditing of financial graphs, and urges preparers and users of annual reports to be wary of the possibility of graph distortion.

Graph usage in annual reports, evidence from Norwegian listed companies

As investors and other users of annual reports often focus their attention on graphs, it is important that they portray accurate and reliable information. However, previous studies show that graphs often distort information and mislead users. This study analyses graph usage in annual reports from the 52 most traded Norwegian companies. The findings suggest that Norwegian companies commonly use graphs, and that the graph distortions, presentational enhancement and measurement distortion, are present. No evidence of selectivity was found. This study recommends development of guidelines for graphical disclosure, and advises preparers and users of annual reports to be aware of misleading graphs.

Modeling usage of medical care services: the medical expenditure panel survey data, 1996-2000

We explore the determinants of usage of six different types of health care services, using the Medical Expenditure Panel Survey data, years 1996-2000. We apply a number of models for univariate count data, including semiparametric, semi-nonparametric and finite mixture models. We find that the complexity of the model that is required to fit the data well depends upon the way in which the data is pooled across sexes and over time, and upon the characteristics of the usage measure. Pooling across time and sexes is almost always favored, but when more heterogeneous data is pooled it is often the case that a more complex statistical model is required.

Une étude qualitative sur l'usage des cigarettes électroniques (e-cigarettes) chez les jeunes

La cigarette électronique (E-cigarette) est un phénomène relativement récent qui est en train de prendre une ampleur inattendue, surtout chez les jeunes. La littérature scientifique à ce sujet est encore relativement rare et surtout centrée sur les taux de prévalence. Bien que théoriquement conçues pour les adultes qui voudraient arrêter de fumer, les adolescents sont devenus un public cible pour ces produits, dont beaucoup n'ayant jamais fumé de cigarettes traditionnelles. Du point de vue de la santé publique, une des préoccupations majeures correspond au possible effet indésirable des cigarettes électroniques d'inciter les jeunes au tabagisme. Beaucoup de questions restent sans réponse quant à l'impact des cigarettes électroniques sur la santé publique. Par exemple, il n'est pas clair si les cigarettes électroniques sont juste une nouveauté que les jeunes n'essayent qu'une fois ou si elles ont le potentiel de concurrencer les cigarettes traditionnelles. Même si les cigarettes électroniques sont disponibles en Suisse depuis près de 10 ans, peu de données existent quant aux motifs de consommation des jeunes, les modalités de consommation, les effets recherchés et la perception de leur nocivité.