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Publicações

2016

Competitive Targeted Advertising with Price Discrimination

Autores
Esteves, RB; Resende, J;

Publicação
MARKETING SCIENCE

Abstract
This paper examines how firms should allocate their advertising budgets between consumers who have a high preference for their products (i.e., strong segment) and those who prefer competing products (i.e., weak segment). Targeted advertising transmits relevant information to otherwise uninformed consumers and it is used as a price discrimination device. With targeted advertising and price discrimination, we find that, when the attractiveness of the weak segment is low, each firm advertises more intensively in its strong segment. The same result arises when the attractiveness of the weak segment is high and advertising is sufficiently expensive. Interestingly, when the attractiveness of the weak segment is high but advertising costs are sufficiently low, it is optimal for each firm to advertise more intensively in its weak segment. The paper also investigates how advertising strategies and equilibrium profits are affected by price discrimination. Compared with uniform pricing, firms can increase or reduce the intensity of advertising targeted to each segment when price discrimination is allowed. Furthermore, when the attractiveness of the weak market is high, price discrimination boosts firms' profits provided that advertising costs are sufficiently low. The reverse happens when advertising costs are high.

2016

ANN-based scenario generation methodology for stochastic variables of electric power systems

Autores
Vagropoulos, SI; Kardakos, EG; Simoglou, CK; Bakirtzis, AG; Catalao, JPS;

Publicação
ELECTRIC POWER SYSTEMS RESEARCH

Abstract
In this paper a novel scenario generation methodology based on artificial neural networks (ANNs) is proposed. The methodology is flexible and able to generate scenarios for various stochastic variables that are used as input parameters in the stochastic short-term scheduling models. Appropriate techniques for modeling the cross-correlation of the involved stochastic processes and scenario reduction techniques are also incorporated into the proposed approach. The applicability of the methodology is investigated through the creation of electric load, photovoltaic (PV) and wind production scenarios and the performance of the proposed ANN-based methodology is compared to time series-based scenario generation models. Test results on the real-world insular power system of Crete and mainland Greece present the effectiveness of the proposed ANN-based scenario generation methodology.

2016

Measuring the intuitive response of users when faced with different interactive paradigms to control a gastroenterology CAD system

Autores
Abrantes, D; Gomes, P; Pereira, D; Coimbra, M;

Publicação
2016 38TH ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY (EMBC)

Abstract
The gastroenterology specialty could benefit from the introduction of Computer Assisted Decision (CAD) systems, since gastric cancer is a serious concern in which an accurate and early diagnosis usually leads to a good prognosis. Still, the way doctors interact with these systems is very important because it will often determine its embracement or rejection, as any gains in productivity will frequently hinge on how comfortable they are with it. Using other types of interaction paradigms such as voice and motion control, is important in a way that typical inputs such as keyboard and mouse are sometimes not the best choice for certain clinical scenarios. In order to ascertain how a doctor could control a hypothetical CAD system during a gastroenterology exam, we measured the natural response of users when faced with three different task requests, using three types of interaction paradigms: voice, gesture and endoscope. Results fit in what was expected, with gesture control being the most intuitive to use, and the endoscope being on the other edge. All the technologies are mature enough to cope with the response concepts the participants gave us. However, when having into account the scenario context, better natural response scores may not always be the best choice for implementation. That way, simplification or reduction of tasks, along with a well tought-out interface, or even mixing more oriented paradigms for particular requests, could allow for better system control with fewer inconveniences for the user.

2016

From information systems and technologies to a technological proposal for an agri-food industry information system: The sousacamp group [Das tecnologias e sistemas de informação à proposta tecnológica de um sistema de informação para a agroindústria: O grupo sousacamp]

Autores
Branco, F; Martins, J; Gonçalves, R;

Publicação
RISTI - Revista Iberica de Sistemas e Tecnologias de Informacao

Abstract
The agri-food industry has been growing at a considerable pace over the recent years. An example of this growth is the mushroom production sector, whose specificities associated with the production process enforce a very controlled management of all the resources applied to that activity. Considering that the existing literature does not present a transverse solution to the referred activity sector, we have endured in an effort to present a technological proposal for an information system directed to the mushroom production sector. The presented proposal, composed by 13 interconnected functional blocks, is the result of a detailed analysis to the technical and functional requirements of Sousacamp Group - a leading organization from the mushroom production sector - merged with the arguments and perspectives presented by technology adoption theories.

2016

A myographic-based HCI solution proposal for upper limb amputees

Autores
Matos, A; Adao, T; Magalhaes, L; Peres, E;

Publicação
INTERNATIONAL CONFERENCE ON ENTERPRISE INFORMATION SYSTEMS/INTERNATIONAL CONFERENCE ON PROJECT MANAGEMENT/INTERNATIONAL CONFERENCE ON HEALTH AND SOCIAL CARE INFORMATION SYSTEMS AND TECHNOLOGIES, CENTERIS/PROJMAN / HCIST 2016

Abstract
Interaction plays a fundamental role as it sets bridges between humans and computers. However, people with disability are prevented to use computers by the ordinary means, due to physical or intellectual impairments. Thus, the human-computer interaction (HCI) research area has been developing solutions to improve the technological accessibility of impaired people, by enhancing computers and similar devices with the necessary means to attend to the different disabilities, thereby contributing to reduce digital exclusion. Within the aforementioned scope, this paper presents an interaction solution for upper limb amputees, supported on a myographic gesture-control device named Myo. This device is an emergent wearable technology, which consists in a muscle-sensitive bracelet. It transmits myographic and inertial data, susceptible of being converted into actions for interaction purposes (e.g. clicking or moving a mouse cursor). Although being a gesture control armband, Myo can also be used in the legs, as was ascertained through some preliminary tests with users. Both data types (myographic and inertial) remain to be transmitted and are available to be converted into gestures. A general architecture, a use case diagram and the two main functional modules specification are presented. These will guide the future implementation of the proposed Myo-based HCI solution, which is intended to be a solid contribution for the interaction between upper limb amputees and computers. (C) 2016 The Authors. Published by Elsevier B.V.

2016

User Redirection and Direct Haptics in Virtual Environments

Autores
Carvalheiro, C; Nóbrega, R; da Silva, H; Rodrigues, R;

Publicação
MM'16: PROCEEDINGS OF THE 2016 ACM MULTIMEDIA CONFERENCE

Abstract
This paper proposes a haptic interaction system for Virtual Reality (VR) based on a combination of tracking devices for hands and objects and a real-to-virtual mapping system for user redirection. In our solution the user receives haptic stimuli by manipulating real objects mapped to virtual objects. This solution departs from systems that rely on haptic devices (e.g., haptic gloves) as interfaces for the user to interact with objects in the Virtual Environment (VE). As such, the proposed solution makes use of direct haptics (touching) and redirection techniques to guide the user through the virtual environment. Using the mapping framework, when the user touches a virtual object in the VE, he will simultaneously be physically touching the equivalent real object. A relevant feature of the framework is the possibility to define a warped mapping between the real and virtual worlds, such that the relation between the user and the virtual space can be different from the one between the user and the real space. This is particularly useful when the application requires the emulation of large virtual spaces but the physical space available is more confined. To achieve this, both the user's hands and the objects are tracked. In the presented prototype we use a head-mounted depth sensor (i.e., Leap Motion) and a depth-sensing camera (i.e., Kinect). To assess the feasibility of this solution, a functional prototype and a room setup with core functionality were implemented. The test sessions with users evaluated the mapping accuracy, the user execution time and the awareness of the user regarding the warped space when performing tasks with redirection. The results gathered indicate that the solution can be used to provide direct haptic feedback in VR applications and for warping space perception within certain limits.

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