Cookies Policy
The website need some cookies and similar means to function. If you permit us, we will use those means to collect data on your visits for aggregated statistics to improve our service. Find out More
Accept Reject
  • Menu
Publications

2018

Development of a ground truth localization system for wheeled mobile robots in indoor environments based on laser range-finder for low-cost systems

Authors
Piardi, L; Lima, J; Costa, P;

Publication
ICINCO 2018 - Proceedings of the 15th International Conference on Informatics in Control, Automation and Robotics

Abstract
The localization systems are becoming more and more required in the actual flexible manufacturing systems based on mobile robots. There are several approaches to localize a mobile robot such as laser scanners reflective beacons, image mapping, lightning based systems, Ultra-wideband time-of-flight trilateration, odometry and fusion sensor data algorithms. During the development phase of a localization methodology, it is necessary to evaluate the proposed system: it is used a ground truth system. Ground truth systems are precise (usually based on reflective beacons) but expensive. This paper presents a low-cost ground truth system based on a standard low-cost laser scanner that, coupled with the presented algorithm, allows to localize the robot in the field and thus evaluate other localization systems. Results of the precision of the developed system are presented and validates the approach. Copyright

2018

On the Track of ISO/IEC 27001:2013 Implementation Difficulties in Portuguese Organizations

Authors
Longras, A; Pereira, T; Carneiro, P; Pinto, P;

Publication
2018 9TH INTERNATIONAL CONFERENCE ON INTELLIGENT SYSTEMS (IS)

Abstract
The security standard ISO/IEC 27001 provides orientations to support organizations to set adequate best practices in information security management, specifying requirements that enable the appropriate selection and implementation of security controls. This standard assists organizations to protect their information assets, achieve their adequate levels of security and thus help them to succeed their business goals. Currently, an increasing number of Portuguese organizations seek to comply ISO/IEC 27001:2013 standard and obtain the respective certification. This paper presents the result of a research conducted in order to detail the main difficulties and limitations evidenced by Portuguese organizations while meeting the ISO/IEC 27001:2013 standard. Moreover, this paper provides discussion on the results obtained, to better understand the progress and status quo of this standard implementation. From the research conducted it can be seen that organizations are becoming heavily concerned with information security issues, mainly due it to the recent cybersecurity incidents occurred. Additionally, certification is recognized as an important instrument to give confidence and demonstrate to all organizational' customers, suppliers and stakeholders that information security components are verified and organized within the organization.

2018

Parallel Polyglot Query Processing on Heterogeneous Cloud Data Stores with LeanXcale

Authors
Kolev, B; Levchenko, O; Pacitti, E; Valduriez, P; Vilaça, R; Gonçalves, RC; Peris, RJ; Kranas, P;

Publication
IEEE International Conference on Big Data (IEEE BigData 2018), Seattle, WA, USA, December 10-13, 2018

Abstract

2018

GENERATING THE ALGEBRAIC THEORY OF C(X): THE CASE OF PARTIALLY ORDERED COMPACT SPACES

Authors
Hofmann, D; Neves, R; Nora, P;

Publication
THEORY AND APPLICATIONS OF CATEGORIES

Abstract
It is known since the late 1960's that the dual of the category of compact Hausdoroff spaces and continuous maps is a variety - not finitary, but bounded by aleph(1). In this note we show that the dual of the category of partially ordered compact spaces and monotone continuous maps is an aleph(1)-ary quasivariety, and describe partially its algebraic theory. Based on this description, we extend these results to categories of Vietoris coalgebras and homomorphisms on ordered compact spaces. We also characterise the aleph(1)-copresentable partially ordered compact spaces.

2018

A Statistical Comparative Study of Photoplethysmographic Signals in Wrist-Worn and Fingertip Pulse-Oximetry Devices

Authors
Gadhoumi, K; Keenan, K; Pereira, T; Colorado, R; Meisel, K; Hu, X;

Publication
Computing in Cardiology Conference (CinC) - 2018 Computing in Cardiology Conference (CinC)

Abstract

2018

Image phase shift invariance based cloud motion displacement vector calculation method for ultra-short-term solar PV power forecasting

Authors
Wang, F; Zhen, Z; Liu, C; Mi, ZQ; Hodge, SM; Shafie khah, M; Catalao, JPS;

Publication
ENERGY CONVERSION AND MANAGEMENT

Abstract
Irradiance received on the earth's surface is the main factor that affects the output power of solar PV plants, and is chiefly determined by the cloud distribution seen in a ground-based sky image at the corresponding moment in time. It is the foundation for those linear extrapolation-based ultra-short-term solar PV power forecasting approaches to obtain the cloud distribution in future sky images from the accurate calculation of cloud motion displacement vectors (CMDVs) by using historical sky images. Theoretically, the CMDV can be obtained from the coordinate of the peak pulse calculated from a Fourier phase correlation theory (FPCT) method through the frequency domain information of sky images. The peak pulse is significant and unique only when the cloud deformation between two consecutive sky images is slight enough, which is likely possible for a very short time interval (such as 1 min or shorter) with common changes in the speed of cloud. Sometimes, there will be more than one pulse with similar values when the deformation of the clouds between two consecutive sky images is comparatively obvious under fast changing cloud speeds. This would probably lead to significant errors if the CMDVs were still only obtained from the single coordinate of the peak value pulse. However, the deformation estimation of clouds between two images and its influence on FPCT-based CMDV calculations are terrifically complex and difficult because the motion of clouds is complicated to describe and model. Therefore, to improve the accuracy and reliability under these circumstances in a simple manner, an image-phase-shift-invariance (IPSI) based CMDV calculation method using FPCT is proposed for minute time scale solar power forecasting. First, multiple different CMDVs are calculated from the corresponding consecutive images pairs obtained through different synchronous rotation angles compared to the original images by using the FPCT method. Second, the final CMDV is generated from all of the calculated CMDVs through a centroid iteration strategy based on its density and distance distribution. Third, the influence of different rotation angle resolution on the final CMDV is analyzed as a means of parameter estimation. Simulations under various scenarios including both thick and thin clouds conditions indicated that the proposed IPSI-based CMDV calculation method using FPCT is more accurate and reliable than the original FPCT method, optimal flow (OF) method, and particle image yelocimetry (PIV) method.

  • 1779
  • 4212