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Publicações

Publicações por CESE

2013

Exploring the Drivers of E-Commerce through the Application of Structural Equation Modeling

Autores
Castro, AFG; Meneses, RFC; Moreira, MRA;

Publicação
EXPLORING SERVICES SCIENCE, IESS 2013

Abstract
E-commerce is a form of trade that has gained increasing attention from consumers and sellers. However, despite high growth rates, e-commerce still has low levels of consumers. This study aims to determine the factors that influence the purchasing decision in e-commerce, in order to better understand acceptance or rejection of e-commerce among consumers. To this end, a first framework was constructed based on previous research on consumer adoption of e-commerce. Then, three categories (derived from interviews) were added. This more complete model was tested using the structural equation model based on partial least squares. The results obtained allow us to conclude that the perceived relative advantage, the ease of use, the drawbacks associated with a non-European Union country of sale and the perceived risk, directly influence the consumer's purchase intent in e-commerce. We also found a set of twelve variables that act as indirect influences.

2013

Application of Artificial Neural Networks to Predict the Impact of Traffic Emissions on Human Health

Autores
Fontes, T; Silva, LM; Pereira, SR; Coelho, MC;

Publicação
PROGRESS IN ARTIFICIAL INTELLIGENCE, EPIA 2013

Abstract
Artificial Neural Networks (ANN) have been essentially used as regression models to predict the concentration of one or more pollutants usually requiring information collected from air quality stations. In this work we consider a Multilayer Perceptron (MLP) with one hidden layer as a classifier of the impact of air quality on human health, using only traffic and meteorological data as inputs. Our data was obtained from a specific urban area and constitutes a 2-class problem: above or below the legal limits of specific pollutant concentrations. The results show that an MLP with 40 to 50 hidden neurons and trained with the cross-entropy cost function, is able to achieve a mean error around 11%, meaning that air quality impacts can be predicted with good accuracy using only traffic and meteorological data. The use of an ANN without air quality inputs constitutes a significant achievement because governments may therefore minimize the use of such expensive stations.

2013

How wide should be the adjacent area to an urban motorway to prevent potential health impacts from traffic emissions?

Autores
Barros, N; Fontes, T; Silva, MP; Manso, MC;

Publicação
TRANSPORTATION RESEARCH PART A-POLICY AND PRACTICE

Abstract
In recent years, several studies show that people who live, work or attend school near the main roadways have an increased incidence and severity of health problems that may be related with traffic emissions of air pollutants. The concentrations of near-road atmospheric pollutants vary depending on traffic patterns, environmental conditions, topography and the presence of roadside structures. In this study, the vertical and horizontal variation of nitrogen dioxide (NO2) and benzene (C6H6) concentration along a major city ring motorway were analysed. The main goal of this study is to try to establish a distance from this urban motorway considered "safe" concerning the air pollutants human heath limit values and to study the influence of the different forcing factors of the near road air pollutants transport and dispersion. Statistic significant differences (p = 0.001, Kruskal-Wallis test) were observed between sub-domains for NO2 representing different conditions of traffic emission and pollutants dispersion, but not for C6H6 (p = 0.335). Results also suggest significant lower concentrations recorded at 100 m away from roadway than at the roadside for all campaigns (p <0.016 (NO2) and p <0.036 (C6H6), Mann-Whitney test). In order to have a "safe" life in homes located near motorways, the outdoor concentrations of NO2 must not exceed 44-60.0 mu g m(-3) and C6H6 must not exceed 1.4-3.3 mu g m(-3). However, at 100 m away from roadway, 81.8% of NO2 receptors exceed the annual limit value of human health protection (40 mu g m(-3)) and at the roadside this value goes up to 95.5%. These findings suggest that the safe distance to an urban motorway roadside should be more at least 100 m. This distance should be further studied before being used as a reference to develop articulated urban mobility and planning policies.

2013

Meta-organization and manufacturing Web 3.0 for ubiquitous virtual enterprise of manufacturing SMEs: a framework

Autores
Castro, H; Putnik, G; Cruz Cunha, MM; Ferreira, L; Shah, V; Alves, C;

Publicação
EIGHTH CIRP CONFERENCE ON INTELLIGENT COMPUTATION IN MANUFACTURING ENGINEERING

Abstract
Manufacturing small and medium-sized enterprises (SMEs) are drivers for economic and social development. Their importance and competitive challenges are increasing interest and attention on private and public sectors due to hyper-competition environment. In order to establish an environment that, not only, addresses hyper-competition but also sustainability, a Meta-Organization is proposed to support advanced manufacturing business models, namely, Virtual and Ubiquitous Enterprises. This Meta-Organization is organizational platform supported by information and communication technologies (ICT), such as Web 3.0. The paper introduces a framework to approach Ubiquitous Virtual Enterprises using Meta-Organization and Manufacturing Web 3.0, adopted by manufacturing SMEs. This paper is organized in six chapters. The chapter 1 presents the environment context that manufacturing SMEs faces and introduces the framework used in the paper. In chapter 2, a review addressing Meta-Organization in context of Ubiquitous Virtual Enterprises is presented. Chapter 3 covers the topic of Meta-Organizations members, specifically manufacturing SMEs. In chapter 4, to meet the technological platform Manufacturing Web 3.0 some Web 3.0 technologies are presented. Chapter 5 presents shortly the overall framework. Finally, chapter 6 draws conclusions. (C) 2013 The Authors. Published by Elsevier B.V.

2013

Cloudlet architecture for dashboard in cloud and ubiquitous manufacturing

Autores
Ferreira, L; Putnik, G; Cunha, M; Putnik, Z; Castro, H; Alves, C; Shah, V; Varela, MLR;

Publicação
EIGHTH CIRP CONFERENCE ON INTELLIGENT COMPUTATION IN MANUFACTURING ENGINEERING

Abstract
The aim of this paper is to present a cloudlet architecture for dashboard in Cloud and Ubiquitous Manufacturing. In practice means that, with Cloud Computing adoption, Manufacturing requires management applications where ubiquity and effectiveness are enabled. If ubiquity and resources scalability, availability and capacity can be well supported by cloud, pragmatics instruments are required to support effectiveness. The architecture here presented shows the integration of enriched existing (cloud) services, as instances of resources, with layers of new services towards direct and synchronous communication between users. These Rich Internet Application (RIA) components, here named cloudlets, integration, follow dashboards organization patterns and will be supported by emergent web3.0 interaction technologies. In fact, the paper proposes a new Presentation Layer to be used in UMS and (that may be used) in any multi-layer cloud-based web application. (C) 2013 Authors. Published by Elsevier B. V.

2013

Human-computer interactions and user interfaces for remote control of manufacturing systems

Autores
Brkic Dr., VS; Putnik, G; Shah, V; Castro, H; Veljkovic, Z;

Publicação
FME Transactions

Abstract
This paper refers to the new direction for enhancement in traditional remote controlling functionality in manufacturing systems. Employing a diversity of tools such as videoconferencing, computer supported cooperative work tools, immersive virtual reality, virtual environment tools, such as "Metaverse" tools, and Internet through Pragmatic Web, is necessary for overcoming the "space barrier". Therefore, further analysis of human-machine user interface is crucial for user interaction with manufacturing systems through remote control. That is the motivation for investigation on evaluation of the user interfaces for remote control of manufacturing systems within the above-mentioned framework. Preliminary results of the evaluation of two types of interfaces are presented in this paper. These two interfaces are distinctive in one particular presentational aspect, while all the remote controlling functionalities are equal for both. The results show that one user interface type clearly fares better than the other over a number of factors as graded by users. © Faculty of Mechanical Engineering, Belgrade.

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