Evaluation of Xgboost and Lgbm Performance in Tree Species Classification with Sentinel-2 Data

Los, H., Mendes, G. S., Cordeiro, D., Grosso, N., Costa, H., Benevides, P., & Caetano, M. (2021). Evaluation of Xgboost and Lgbm Performance in Tree Species Classification with Sentinel-2 Data. In IGARSS 2021 - 2021 IEEE International Geoscience and Remote Sensing Symposium: Proceedings (pp. 5803-5806). IEEE. https://doi.org/10.1109/IGARSS47720.2021.9553031Tree species classification with satellite data has become more and more popular since Sentinel-2 launch. We compared efficacy and effectiveness of Extreme Gradient Boosting (XGBoost) and Light Gradient Boosting Machine (LGBM) with widely used in remote sensing Random Forest (RF), Support Vector Machine (SVM) and K-Nearest Neighbour (KNN) algorithms. Analyses were performed over an area in Portugal with multi-temporal Sentinel-2 data registered in April, June, August and October 2018. The selected classes were: cork oak, holm oak, eucalyptus, other broadleaved, maritime pine, stone pine and other coniferous. Algorithm efficacy was measured through F1-score and accuracy while efficiency was measured through the median time needed for each fit. XGBoost and LGBM outperformed efficacy of other algorithms, which was already high (above 90% for the best variant of each algorithm). In terms of efficacy, LGBM overcame all algorithms, including XGBoost.authorsversionpublishe

Dual-Polarized Massive MIMO-RSMA Networks: Tackling Imperfect SIC

The polarization domain provides an extra degree of freedom (DoF) for improving the performance of multiple-input multiple-output (MIMO) systems. This paper takes advantage of this additional DoF to alleviate practical issues of successive interference cancellation (SIC) in rate-splitting multiple access (RSMA) schemes. Specifically, we propose three dual-polarized downlink transmission approaches for a massive MIMO-RSMA network under the effects of polarization interference and residual errors of imperfect SIC. The first approach implements polarization multiplexing for transmitting the users' data messages, which removes the need to execute SIC in the reception. The second approach transmits replicas of users' messages in the two polarizations, which enables users to exploit diversity through the polarization domain. The third approach, in its turn, employs the original SIC-based RSMA technique per polarization, and this allows the BS to transmit two independent superimposed data streams simultaneously. An in-depth theoretical analysis is carried out, in which we derive tight closed-form approximations for the outage probabilities of the three proposed approaches. Accurate approximations for the ergodic sum-rates of the two first schemes are also derived. Simulation results validate the theoretical analysis and confirm the effectiveness of the proposed schemes. For instance, under low to moderate cross-polar interference, the results show that, even under high levels of residual SIC error, our dual-polarized MIMO-RSMA strategies outperform the conventional single-polarized MIMO-RSMA counterpart. It is also shown that the performance of all RSMA schemes is impressively higher than that of single and dual-polarized massive MIMO systems employing non-orthogonal multiple access (NOMA) and orthogonal multiple access (OMA) techniques

Silicon anisotropy in a bi-dimensional optomechanical cavity

In this work, we study the effects of mechanical anisotropy in a 2D optomechanical crystal geometry. We fabricate and measure devices with different orientations, showing the dependence of the mechanical spectrum and the optomechanical coupling with the relative angle of the device to the crystallography directions of silicon. Our results show that the device orientation strongly affects its mechanical band structure, which makes the devices more susceptible to fabrication imperfections. Finally, we show that our device is compatible with cryogenic measurements reaching ground state occupancy of 0.2 phonons at mK temperature.Comment: 5 pages 4 figure

Avaliação da porcentagem de germinação em sementes recém-colhidas de quatro cultivares de arroz irrigado.

O trabalho teve como objetivo avaliar a porcentagem de germinação em grãos em seis épocas de colheita, espaçadas sete dias uma da outra, em quatro cultivares de arroz irrigado (BRS Catiana, BRS A702 CL, BRS Pampeira e IRGA 424)dentro de quatro sistemas de irrigação (ICC = inundação contínua, IIF = inundação intermitente até o florescimento, IIC = inundação intermitente durante o ciclo, e SSC = solo saturado)

Logics for Petri nets with propagating failures

Petri nets play a central role in the formal modelling of a wide range of complex systems and scenarios. Their ability to handle with both concurrency and resource awareness justifies their spread in the current formal development practices. On the logic side, Dynamic Logics are widely accepted as the de facto formalisms to reason about computational systems. However, as usual, the application to new situations raises new challenges and issues. The ubiquity of failures in the execution of current systems, interpreted in these models as triggered events that are not followed by the corresponding transition, entails not only the adjustment of these structures to deal with this reality, but also the introduction of new logics adequate to this emerging phenomenon. This paper contributes to this challenge by exploring a combination of two previous works of the authors, namely the Propositional Dynamic Logic for Petri Nets [1] and a parametric construction of multi-valued dynamic logics presented in [13]. This exercise results in a new family of Dynamic Logics for Petri Nets suitable to deal with firing failures.publishe

Reação de fontes de resistência internacionais a isolados brasileiros de Magnaporthe oryzae em condições de campo.

Magnaporthe oryzae é o patógeno mais importante da cultura do arroz em todo o mundo. Dada a variabilidade das populações do patógeno, há uma busca incessante por fontes de resistência que sejam estáveis e duráveis. Na literatura mundial, há cerca de 60 genótipos descritos como resistentes a um número expressivo de isolados e, por isso, são consideradas fontes potenciais de resistência. Para este trabalho foram utilizadas 23 fontes internacionais de resistência a brusone com o objetivo de avaliar a resistência a isolados brasileiros em condições de camp

Long-term optical variability of the blazars PKS 2005-489 and PKS 2155-304

We present optical light curves for the period 1996-2000, of two of the brightest known EGRET BL Lac objects: PKS 2005-489 and PKS 2155-304, the latter also one of the few known TeV sources. For both objects, quiescent epochs of low level of variability were followed by active periods, without any indication of periodicity. In PKS 2005-489, several variability events with duration of about 20 days were observed. In PKS 2155-304 fast drops and subsequent rises in luminosity occurred in time scales of days. We proposed an explanation in which a region moving along the relativistic jet is eclipsed by broad line region clouds or star clusters in the host galaxy. We compare our light curves with contemporaneous X-ray observations from All-Sky Monitor/RXTE. Correlations between optical and X-ray activity were not found in any of the sources at long time scales. However in PKS 2005-489 possible correlations were observed in 1997 and 1998 at short time scales, with optical variability preceding X-rays by 30 days in 1997 and succeeding them by about 10 days in 1998. The analysis of the SED, using the optical data presented here and BeppoSAX contemporaneous observations obtained from the literature, shows only small shifts in the synchrotron peak as the X-ray flux density changes.Comment: 23 pages,12 figures, accepted for publication in A

Verification for Everyone? An Overview of Dynamic Logic

This note, reporting the homonym keynote presented in the International Symposium on Molecular Logic and Computational Synthetic Biology 2018, traces an informal roadmap on Dynamic Logic (DL) field, focusing on its versatility and resilience to be adjusted and adopted in a wide class of application domains and computational paradigms. The exposition argues the room for developments on tagging DL to the analysis of synthetic biologic domain.publishe

Digitaalinen kuvankäsittely ja etiikka : Haastattelututkimus Helsingin Sanomien kuvatoimitusten eettisestä päätöksenteosta

Endast sammandrag. Inbundna avhandlingar kan sökas i Helka-databasen (http://www.helsinki.fi/helka). Elektroniska kopior av avhandlingar finns antingen öppet på nätet eller endast tillgängliga i bibliotekets avhandlingsterminaler.Only abstract. Paper copies of master’s theses are listed in the Helka database (http://www.helsinki.fi/helka). Electronic copies of master’s theses are either available as open access or only on thesis terminals in the Helsinki University Library.Vain tiivistelmä. Sidottujen gradujen saatavuuden voit tarkistaa Helka-tietokannasta (http://www.helsinki.fi/helka). Digitaaliset gradut voivat olla luettavissa avoimesti verkossa tai rajoitetusti kirjaston opinnäytekioskeilla.Digitaalisen kuvankäsittelyyn liittyvän etiikan tutkimus on Suomessa ollut melko olematonta. Tutkimukselle on kuitenkin tarvetta, sillä sekä tekninen kehitys että erilaiset muutokset ajattelutavoissa lisäävät eettisen pohdinnan tarvetta. Tämä tutkimus pyrkii osaltaan täyttämään tällä hetkellä kuvajournalismin tutkimuksessa vallitsevaa aukkoa. Tutkielmassa on tarkasteltu, millaisena digitaalisen kuvankäsittelyn etiikka näyttäytyy sanomalehdessä. Tut-kimuksen kohteena oli Helsingin Sanomien kuvatoimitusten henkilökunta ja tutkimusmenetelmänä käytettiin teemahaastattelua. Tutkimuksen tavoitteena oli etsiä vastauksia seuraaviin erillisiin tutkimuskysymyksiin: mihin etiikkakäsitykseen kuvajournalistien käsitykset pohjautuvat, kenelle tutkittavat ovat lojaaleja ja mitkä tilannetekijät he ottavat huomioon sekä mitkä eettiset arvot ohjaavat Helsingin Sanomien kuvankäsittelyä? Digitaalisen kuvankäsittelyn etiikan tutkiminen aloitettiin soveltamalla professori Ralph Potterin alunperin teologian puolelle kehittelemää eettisen päätöksenteon mallia kuvajournalismin tutkimukseen. Mallin pohjalta haastateltiin 13 Helsingin Sanomien kuvatoimituksen työntekijää. Vastaukset analysoitiin teemoittelemalla, käyttäen edelleen apuna Potterin mallia. Malli osoittautui hyväksi työkaluksi tutkia eettistä päätöksentekoa. Tulosten perusteella haastateltujen eettinen päätöksenteko ei näyttäisi olevan kovinkaan tietoista tai hyvin perusteltua. Digitaalisen kuvankäsittelyn etiikkaa ei enemmistön mielestä tarvinnut erityisesti pohtia, koska kuvamanipulaatioita ei Helsingin Sanomissa pääsääntöisesti tehdä. Tämän lisäksi suhtautuminen digitaalisen kuvankäsittelyn korjailutarkoitusta laajempaan käyttöön oli vastaajien keskuudessa melko kielteinen. Näiden tulosten pohjalta tutkimuksessa pohditaan myös sitä, olisiko digitaalista kuvankäsittelyä mahdollista käyttää nykyistä enemmän sanomalehtien sivuilla. Eettisesti pitävästi perusteltujen, manipuloitujen kuvien käyttö saattaisi uudistaa kuvajournalismia myönteisellä tavalla. Tämä edellyttää sitä, että pidetään huolta siitä, etteivät tällaiset kuvat harhauta lukijoita. Asiaa havainnollistetaan tutkimuksessa kuvaesimerkkien avulla. Teknistä kehitystä ei tutkimuksessa nähdä uhkana lehtikuvan uskottavuudelle vaan pikemminkin mahdollisuutena kehittää sanomalehtikuvien ilmaisukykyä

Neutrophils in cancer: neutral no more

Neutrophils are indispensable antagonists of microbial infection and facilitators of wound healing. In the cancer setting, a newfound appreciation for neutrophils has come into view. The traditionally held belief that neutrophils are inert bystanders is being challenged by the recent literature. Emerging evidence indicates that tumours manipulate neutrophils, sometimes early in their differentiation process, to create diverse phenotypic and functional polarization states able to alter tumour behaviour. In this Review, we discuss the involvement of neutrophils in cancer initiation and progression, and their potential as clinical biomarkers and therapeutic targets