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Publicações

2020

WiCAR - Simulating Towards the Wireless Car

Autores
Kurunathan, H; Severino, R; Filho, EV; Tovar, E;

Publicação
SAFECOMP Workshops

Abstract
Advanced driving assistance systems (ADAS) pose stringent requirements to a system’s control and communications, in terms of timeliness and reliability, hence, wireless communications have not been seriously considered a potential candidate for such deployments. However, recent developments in these technologies are supporting unprecedented levels of reliability and predictability. This can enable a new generation of ADAS systems with increased flexibility and the possibility of retrofitting older vehicles. However, to effectively test and validate these systems, there is a need for tools that can support the simulation of these complex communication infrastructures from the control and the networking perspective. This paper introduces a co-simulation framework that enables the simulation of an ADAS application scenario in these two fronts, analyzing the relationship between different vehicle dynamics and the delay required for the system to operate safely, exploring the performance limits of different wireless network configurations.

2020

Evaluation of Hunting-Based Optimizers for a Quadrotor Sliding Mode Flight Controller

Autores
Oliveira, J; Oliveira, PM; Boaventura Cunha, J; Pinho, T;

Publicação
ROBOTICS

Abstract
The design of Multi-Input Multi-Output nonlinear control systems for a quadrotor can be a difficult task. Nature inspired optimization techniques can greatly improve the design of non-linear control systems. Two recently proposed hunting-based swarm intelligence inspired techniques are the Grey Wolf Optimizer (GWO) and the Ant Lion Optimizer (ALO). This paper proposes the use of both GWO and ALO techniques to design a Sliding Mode Control (SMC) flight system for tracking improvement of altitude and attitude in a quadrotor dynamic model. SMC is a nonlinear technique which requires that its strictly coupled parameters related to continuous and discontinuous components be correctly adjusted for proper operation. This requires minimizing the tracking error while keeping the chattering effect and control signal magnitude within suitable limits. The performance achieved with both GWO and ALO, considering realistic disturbed flight scenarios are presented and compared to the classical Particle Swarm Optimization (PSO) algorithm. Simulated results are presented showing that GWO and ALO outperformed PSO in terms of precise tracking, for ideal and disturbed conditions. It is shown that the higher stochastic nature of these hunting-based algorithms provided more confidence in local optima avoidance, suggesting feasibility of getting a more precise tracking for practical use.

2020

Trends and Innovations in Information Systems and Technologies - Volume 3, WorldCIST 2020, Budva, Montenegro, 7-10 April 2020

Autores
Rocha, A; Adeli, H; Reis, LP; Costanzo, S; Orovic, I; Moreira, F;

Publicação
WorldCIST (3)

Abstract

2020

Designing Effective User Interface Experiences for a Self-Service Kiosk to Reduce Emergency Department Crowding

Autores
Pacheco, P; Santos, F; Coimbra, J; Oliveira, E; Rodrigues, NF;

Publicação
2020 IEEE 8TH INTERNATIONAL CONFERENCE ON SERIOUS GAMES AND APPLICATIONS FOR HEALTH (SEGAH 20)

Abstract
Emergency department crowding has been steadily increasing, with a significant part due to non-emergent pathologies. We developed a self-service kiosk to be used by patients while waiting from triage to treatment room allocation, which collects clinical history, usual medication, main complaint and, also collects vital signs. This information is processed and presented in a comprehensive way to the medical staff in order to accelerate diagnostics and treatment selection. This work describes and analyzes the results of the usability evaluation of this kiosk, taking into account the average time per screen, the average time of a complete kiosk session, the application design and the user interaction with devices and the system. The kiosk was tested in several environments with different types of users, allowing the identification of causes of problems and difficulties experienced, as well as solutions to improve the solution.

2020

Modeling Tourists' Personality in Recommender Systems How Does Personality Influence Preferences for Tourist Attractions?

Autores
Alves, P; Saraiva, P; Carneiro, J; Campos, P; Martins, H; Novais, P; Marreiros, G;

Publicação
UMAP'20: PROCEEDINGS OF THE 28TH ACM CONFERENCE ON USER MODELING, ADAPTATION AND PERSONALIZATION

Abstract
Personalization is increasingly being perceived as an important factor for the effectiveness of Recommender Systems (RS). This is especially true in the tourism domain, where travelling comprises emotionally charged experiences, and therefore, the more about the tourist is known, better recommendations can be made. The inclusion of psychological aspects to generate recommendations, such as personality, is a growing trend in RS and they are being studied to provide more personalized approaches. However, although many studies on the psychology of tourism exist, studies on the prediction of tourist preferences based on their personality are limited. Therefore, we undertook a large-scale study in order to determine how the Big Five personality dimensions influence tourists' preferences for tourist attractions, gathering data from an online questionnaire, sent to Portuguese individuals from the academic sector and their respective relatives/friends (n=508). Using Exploratory and Confirmatory Factor Analysis, we extracted 11 main categories of tourist attractions and analyzed which personality dimensions were predictors (or not) of preferences for those tourist attractions. As a result, we propose the first model that relates the five personality dimensions with preferences for tourist attractions, which intends to offer a base for researchers of RS for tourism to automatically model tourist preferences based on their personality.

2020

Design and Implementation of Secret Key Agreement for Platoon-based Vehicular Cyber-physical Systems

Autores
Li, K; Ni, W; Emami, Y; Shen, Y; Severino, R; Pereira, D; Tovar, E;

Publicação
ACM TRANSACTIONS ON CYBER-PHYSICAL SYSTEMS

Abstract
In a platoon-based vehicular cyber-physical system (PVCPS), a lead vehicle that is responsible for managing the platoon's moving directions and velocity periodically disseminates control messages to the vehicles that follow. Securing wireless transmissions of the messages between the vehicles is critical for privacy and confidentiality of the platoon's driving pattern. However, due to the broadcast nature of radio channels, the transmissions are vulnerable to eavesdropping. In this article, we propose a cooperative secret key agreement (CoopKey) scheme for encrypting/decrypting the control messages, where the vehicles in PVCPS generate a unified secret key based on the quantized fading channel randomness. Channel quantization intervals are optimized by dynamic programming to minimize the mismatch of keys. A platooning testbed is built with autonomous robotic vehicles, where a TelosB wireless node is used for onboard data processing and multi-hop dissemination. Extensive real-world experiments demonstrate that CoopKey achieves significantly low secret bit mismatch rate in a variety of settings. Moreover, the standard NIST test suite is employed to verify randomness of the generated keys, where the p-values of our CoopKey pass all the randomness tests. We also evaluate CoopKey with an extended platoon size via simulations to investigate the effect of system scalability on performance.

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