Search results for "tree"

Gaussian plane and spherical means in separable Hilbert spaces

1982

Spatially dynamic forest management to sustain biodiversity and economic returns.

2014

Production of marketed commodities and protection of biodiversity in natural systems often conflict and thus the continuously expanding human needs for more goods and benefits from global ecosystems urgently calls for strategies to resolve this conflict. In this paper, we addressed what is the potential of a forest landscape to simultaneously produce habitats for species and economic returns, and how the conflict between habitat availability and timber production varies among taxa. Secondly, we aimed at revealing an optimal combination of management regimes that maximizes habitat availability for given levels of economic returns. We used multi-objective optimization tools to analyze data fr…

Investigating serendipity in recommender systems based on real user feedback

2018

Over the past several years, research in recommender systems has emphasized the importance of serendipity, but there is still no consensus on the definition of this concept and whether serendipitous items should be recommended is still not a well-addressed question. According to the most common definition, serendipity consists of three components: relevance, novelty and unexpectedness, where each component has multiple variations. In this paper, we looked at eight different definitions of serendipity and asked users how they perceived them in the context of movie recommendations. We surveyed 475 users of the movie recommender system, MovieLens regarding 2146 movies in total and compared tho…

Methods for estimating forest stem volumes by tree species using digital surface model and CIR images taken from light UAS

2012

In this paper we consider methods for estimating forest tree stem volumes by species using images taken from light unmanned aircraft systems (UAS). Instead of using LiDAR and additional multiband imagery a color infrared camera mounted to a light UAS is used to acquire both imagery and the DSM of target area. The goal of this study is to accurately estimate tree stem volumes in three classes. The status of the ongoing work is described and an initial method for delineating and classifying treetops is presented.

Mitä tänään blogattaisiin? : hyvinvointiblogien sisällöt ja niiden luotettavuus tietolähteenä

2017

Tämän pro gradu –tutkielman tarkoitus oli selvittää, millaisia ravintoon ja fyysiseen harjoitteluun liittyviä teemoja hyvinvointiblogeista nousee esille ja minkälaisia blogin kirjoittajien eli bloggaajien antamat ohjeet ravinnosta ja harjoittelusta ovat suhteessa tämänhetkisiin suosituksiin ja kirjallisuuteen. Tutkimuksen aineisto koostui kolmen suositun bloggaajan kirjoittamista blogiteksteistä kuukauden ajalta (syyskuu 2015). Tutkimus on laadullinen tutkimus, jossa aineisto käsiteltiin sisällönanalyysillä. Analyysin tuloksia suhteutettiin annettuihin terveyssuosituksiin ja kirjallisuuteen tutkijan vertailun avulla. Tutkimuksen aineistosta löydettiin kolme pääluokkaa: asiantuntijuuspuhe, k…

Counting the minimum node weight spanning trees for broadcast transmission in wireless sensor networks

2017

Artykuł przedstawia algorytm optymalizacji zużycia energii dla broadcastu w sieciach sensorowych. Transmisja broadcastu pozwala na wysłanie danych do wszystkich portów składających się na sieć. Bezprzewodowe sieci sensorowe zbudowane są z rozproszonych urządzeń pomiarowych. Mają one ograniczone zasoby energii. W tym artykule stworzymy model sieci sensorowej z jednym sensorem broadcastującym. Do tej sieci użyjemy algorytmu znajdującego minimalne spinające drzewo wag, pozwalające na oszczędne wykorzystanie energii sensorów.

Using machine learning on tree-ring data to determine the geographical provenance of historical construction timbers

2023

Funder: Bavarian Climate Research Network (BayKliF)

A Band Model of Cambium Development: Opportunities and Prospects

2021

More than 60% of tree phytomass is concentrated in stem wood, which is the result of periodic activity of the cambium. Nevertheless, there are few attempts to quantitatively describe cambium dynamics. In this study, we develop a state-of-the-art band model of cambium development, based on the kinetic heterogeneity of the cambial zone and the connectivity of the cell structure. The model describes seasonal cambium development based on an exponential function under climate forcing which can be effectively used to estimate the seasonal cell production for individual trees. It was shown that the model is able to simulate different cell production for fast-, middle- and slow-growing trees under …

Wood formation in pedunculate oak and its relation with climatic factors in Latvia

2013

Šajā darbā ir analizēta parastā ozola (Quercus robur L.) augšanas saistība ar klimatiskajiem faktoriem Latvijā (43 vietas), izmantojot dendrohronoloăijas un dendroekoloģijas metodes. Klimata ietekmes novērtējumam, izmantoja divus atšķirīgus gadskārtu mērījumus: gadskārtu platumu un pavasara koksnes traheju dobumu laukumu. Ozola augšana uzrādīja atšķirības gar austrumu-rietumu gradientu saistībā ar klimata kontinentalitāti. Balstoties uz šo gradientu Latvijas teritoriju var iedalīt divās daļās (rietumu un austrumu reģionā). Gadskārtu platumu rietumu reģionā, galvenokārt, ietekmēja pavasara un vasaras gaisa temperatūra, bet austrumu reģionā klimatisko faktoru, kas ir saistīti ar sausumu vasar…

Monitoring Volcanic Eruptions Using Trace Metals In Tree-Rings: Preliminary Results From Mt. Etna

2010

8. Active volcanoes can influence surrounding vegetation both through passive degassing during quiescent periods and through eruptive degassing, by introducing into the atmosphere several metals as gases and particles. The chemical composition of tree-rings has been generally used to investigate the effects of anthropogenic gas emissions and dendrochemical methods have successfully recorded variations in the pollution levels. The use of tree-rings analysis in active volcanic areas has shown that vascular plants could be used as archives of volcanogenic metals deposition. Tree cores of Pinus Nigra and Populus tremula were collected in sites located both on the downwind (Citelli and Mt. Fonta…