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Publicações

2019

Vineyard Segmentation from Satellite Imagery Using Machine Learning

Autores
Santos, L; Santos, FN; Filipe, V; Shinde, P;

Publicação
PROGRESS IN ARTIFICIAL INTELLIGENCE, EPIA 2019, PT I

Abstract
Steep slope vineyards are a complex scenario for the development of ground robots due to the harsh terrain conditions and unstable localization systems. Automate vineyard tasks (like monitoring, pruning, spraying, and harvesting) requires advanced robotic path planning approaches. These approaches usually resort to Simultaneous Localization and Mapping (SLAM) techniques to acquire environment information, which requires previous navigation of the robot through the entire vineyard. The analysis of satellite or aerial images could represent an alternative to SLAM techniques, to build the first version of occupation grid map (needed by robots). The state of the art for aerial vineyard images analysis is limited to flat vineyards with straight vine’s row. This work considers a machine learning based approach (SVM classifier with Local Binary Pattern (LBP) based descriptor) to perform the vineyard segmentation from public satellite imagery. In the experiments with a dataset of satellite images from vineyards of Douro region, the proposed method achieved accuracy over 90%. © Springer Nature Switzerland AG 2019.

2019

Development of an electromechanical variable buoyancy system for shallow water operations

Autores
Carneiro, JF; Pinto, JB; de Almeida, FG; Cruz, N;

Publicação
OCEANS 2019 - MARSEILLE

Abstract
Autonomous underwater vehicles (AUVs) are becoming increasingly ubiquitous due to the growing needs in exploring Ocean resources. One of the most challenging tasks in this domain relates to the energy these vehicles require, given the increase in the number of scientific payloads and on the mission complexity. One way to potentially reduce the amount of energy consumed during vertical motion is to replace or complement the thruster action with a controlled change of the vehicles floatation, using a variable buoyancy system (VBS). This paper presents the development of an electromechanical VBS for shallow depths, up to 100 m, to be included in an existing AUV. A preliminary mechanical design is presented, along with a mathematical model allowing the calculation of the energy spent by this device, based on the components manufacturers' data. A comparison between the energy consumption using thrusters and the designed VBS is presented. © 2019 IEEE.

2019

Planning a trip online: The Portuguese tourist [Planeamento online de uma viagem: O turista português]

Autores
Valente, G; Leite, C; Cardoso, M; Martins, AL; Moreira, F; Au Yong Oliveira, M;

Publicação
Iberian Conference on Information Systems and Technologies, CISTI

Abstract
This study focuses on the impact of technology and on the planning of a trip by a Portuguese tourist. From the literature review, studies done at the European level, the technology inherent to tourism is provided to the entire age range, and fundamentally to the planning of accommodation, transport and tourist packs. The absorption of information is always highlighted by the easy and fast access to the Internet increasingly accessible to anyone, promoting behavioral changes in tourism planning. Thus, an online survey (with 180 valid answers) was carried out, which focused mainly on university students, and was restricted to Portuguese citizens. The survey determined that online platforms are most used for accommodation (87.2%), transportation (87,2%) and the demand for information (68.8%) to the detriment of catering (7.3%), and these are mainly being used because of their speed (79.4%) and simplicity (80.7%). To conclude, our study confirms the bibliographic review, and it was determined that practically all respondents assume the influence of digital platforms in the planning of their trips (99.1%), with 89% going further and affirming that in the future all planning will be carried out in an exclusive way online. © 2019 AISTI.

2019

Noise Attenuation using Genetic Algorithm in CT Image

Autores
Saraiva, AA; de Oliveira, MS; Sousa, JVM; Ferreira, NMF; Valente, A; Soares, S;

Publicação
PROCEEDINGS OF THE 12TH INTERNATIONAL JOINT CONFERENCE ON BIOMEDICAL ENGINEERING SYSTEMS AND TECHNOLOGIES, VOL 1 (BIODEVICES)

Abstract
The techniques of image filtering have undergone an explosive growth in the last years to make new advances and challenges. This is due to the fact, among several other reasons, the increase of the volume of images coming from several sources. Digital images have been used for a variety of purposes, from the storage of souvenirs to accurate medical exams. However, Images may be corrupted due to several factors. The challenge of suppression or noise attenuation has led to the search for improved techniques in order to preserve important characteristics of the image, but, on the other hand, there is no solution available to completely solve the problem, boosting the production of the work proposed here. In this paper proposes a method for noise attenuation in computed tomography images using a hybrid genetic algorithm, the proposed method seeks to optimize the results in the space of solutions composed by a series of techniques of noise filtering. At the end the proposed method is compared statistically with two other competing methods and after the resulting filtered images are shown.

2019

Monocular Visual Odometry Benchmarking and Turn Performance Optimization

Autores
Aguiar, A; Sousa, A; dos Santos, FN; Oliveira, M;

Publicação
2019 19TH IEEE INTERNATIONAL CONFERENCE ON AUTONOMOUS ROBOT SYSTEMS AND COMPETITIONS (ICARSC 2019)

Abstract
Developing ground robots for crop monitoring and harvesting in steep slope vineyards is a complex challenge due to two main reasons: harsh condition of the terrain and unstable localization accuracy obtained with Global Navigation Satellite System. In this context, a reliable localization system requires an accurate and redundant information to Global Navigation Satellite System and wheel odometry based system. To pursue this goal we benchmark 3 well known Visual Odometry methods with 2 datasets. Two of these are feature-based Visual Odometry algorithms: Libviso2 and SVO 2.0. The third is an appearance-based Visual Odometry algorithm called DSO. In monocular Visual Odometry, two main problems appear: pure rotations and scale estimation. In this paper, we focus on the first issue. To do so, we propose a Kalman Filter to fuse a single gyroscope with the output pose of monocular Visual Odometry, while estimating gyroscope's bias continuously. In this approach we propose a non-linear noise variation that ensures that bias estimation is not affected by Visual Odometry resultant rotations. We compare and discuss the three unchanged methods and the three methods with the proposed additional Kalman Filter. For tests, two public datasets are used: the Kitti dataset and another built in-house. Results show that our additional Kalman Filter highly improves Visual Odometry performance in rotation movements.

2019

Quantum fluid equations for atomic gases

Autores
Guerreiro, A; Ferreira, TD; Silva, NA;

Publicação
FOURTH INTERNATIONAL CONFERENCE ON APPLICATIONS OF OPTICS AND PHOTONICS

Abstract
Although the quantum theory of the optical response of individual atoms to coherent light with frequencies close to electronic transitions and the fluid equations for a gas are well known and understood from first principles, they are developed independently of each other and therefore cannot be applied directly to describe many of the quantum collective and transport phenomena that occur in cold atomic gases, especially in what regards their interaction with optical pulses and beams. Few attempts have been made to derive a consistent formalism and theory that are capable to model this type of systems, and those which exist rely on the adaptation of several ad-hoc hypothesis and simplifications, such as space and time dependent density operators. In this paper we provide the theoretical foundations and establish a formalism capable of paving the way for the development of new simulation tools and to explore new problems in nonlinear optics out of equilibrium.

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