Search results for "Stream"
showing 10 items of 682 documents
Estimating aggregated nutrient fluxes in four Finnish rivers via Gaussian state space models
2013
Reliable estimates of the nutrient fluxes carried by rivers from land-based sources to the sea are needed for efficient abatement of marine eutrophication. Although nutrient concentrations in rivers generally display large temporal variation, sampling and analysis for nutrients, unlike flow measurements, are rarely performed on a daily basis. The infrequent data calls for ways to reliably estimate the nutrient concentrations of the missing days. Here, we use the Gaussian state space models with daily water flow as a predictor variable to predict missing nutrient concentrations for four agriculturally impacted Finnish rivers. Via simulation of Gaussian state space models, we are able to esti…
Predictive models in assessment of macroinvertebrates in boreal rivers
2009
Jukka Aroviita tutki väitöskirjassaan jokien ja purojen biologisen tilan mittaamismenetelmiä. Aroviita osoitti, että ihmistoiminnan aiheuttamat biologiset muutokset voivat jäädä havaitsematta, jos eliöyhteisöjen luonnollista taustavaihtelua ei oteta kunnolla huomioon.- Tällöin vesistöjen saatetaan arvioida olevan paremmassa kunnossa kuin ne todellisuudessa ovatkaan. Muutosten tunnistamistarkkuuden tulisi olla mahdollisimman hyvä, sillä tila-arvioilla on myös juridisesti määräytyviä yhteiskunnallisia ja taloudellisia seuraamuksia, Aroviita toteaa. Vielä 1990-luvulla järvien ja jokien tilaa arvioitiin suurelta osin ihmisen näkökulmasta ja veden kemian perusteella. Nykylainsäädäntö edellyttää …
Fish introductions and light modulate food web fluxes in tropical streams : a whole-ecosystem experimental approach
2016
Decades of ecological study have demonstrated the importance of top-down and bottom-up controls on food webs, yet few studies within this context have quantified the magnitude of energy and material fluxes at the whole-ecosystem scale. We examined top-down and bottom-up effects on food web fluxes using a field experiment that manipulated the presence of a consumer, the Trinidadian guppy Poecilia reticulata, and the production of basal resources by thinning the riparian forest canopy to increase incident light. To gauge the effects of these reach-scale manipulations on food web fluxes, we used a nitrogen (15N) stable isotope tracer to compare basal resource treatments (thinned canopy vs. con…
Leveraging Users' Likes in a Video Streaming P2P Platform
2014
This paper investigates how a p2p television platform can take advantage of the presence of frequent channel viewers to grant them a more satisfying service than to less regular spectators. The idea we explore is to learn beforehand about the users' interests, in order to cluster them in groups that display different behaviors; then, the neighborhood creation strategy and video chunk scheduling algorithm of the overlay is altered, with the aim of serving frequent spectators in a privileged manner, providing them with a faster access to the selected channel without overly penalizing less habitual customers. An analytical model is developed, to capture the difference in startup delay that the…
Stream-analyysi : muutoksen johtamisen apuväline
2002
A regional GIS-based model for reconstructing natural monthly streamflow series at ungauged sites
2016
Several hydrologic applications require reliable estimates of monthly runoff in river basins to face the widespread lack of data, both in time and in space. The main aim of this work is to propose a regional model for the estimation of monthly natural runoff series at ungauged sites, analyzing its applicability, reliability and limitations. A GIS (Geographic Information System) based model is here developed and applied to the entire region of Sicily (Italy). The core of this tool is a regional model for the estimation of monthly natural runoff series, based on a simple modelling structure, consisting of a regression based rainfall-runoff model with only four parameters. The monthly runoff i…
Students' usage patterns of video recorded lectures in an undergraduate mathematics course
2018
International audience; It is customary for some universities to offer recordings of live lectures to students. Whether this improves learning and academic performance is debated in the literature. As with most technology, correct usage can lead to increased academic performance, but there are also usage patterns that can be considered counter productive, especially for learning mathematics. In order to investigate patterns in students' usage of such online recorded live lectures, we analyze log files from a server holding the recordings of an undergraduate mathematics course. This poster presents results from the statistical analysis and discusses some of the usage patterns found in light …
Why English? : Finnish streamers' views on their language choice
2017
Videopelien reaaliaikainen jakaminen on yleistynyt viime vuosina valtavasti ja suoratoistopalvelu Twitch on kerännyt miljoonia pelisessioitaan jakavia kaikkialta maailmasta ja streamaamisesta onkin kehittynyt miljoonabisnes. Tutkielmani perehtyy suomalaisten streamaajien kielivalintoihin, kun he ovat päättäneet käyttää streamiensa kielenä englantia suomen sijasta. Tutkielmani tarkoitus oli selvittää mikä motivoi suomalaiset pelaajat streamaamaan juuri englanniksi ja millaisia näkemyksiä heillä on omaa kielivalintaansa kohtaan ja mikä heidän suhteensa englannin kieleen on. Tutkimukseni koostui kolmen suomalaisen streamaajan haastatteluista. Haastatteluissa pyrin ymmärtämään osallistujien kie…
Institutional arrangements for sustainable development: Cases from the Navarra Province (Spain).
2015
After more than 20 years of the Earth Summit, Sustainable development is still recognized as one of the main challenges of the XXIst century. World leaders are putting new emphasis on the need to resolve urgent environmental challenges underlining their link with the wellbeing of humankind and the very conditions that made life possible on the planet. We are immersed in complex socio-ecological systems where sectoral or simplified responses are not adequate. A more systemic vision is imperative to effectively address the challenges faced. New approaches are being developed to integrate social, environmental and economic concerns in all human activities. Particular attention is given to deco…
On the Students' QoS-Awareness of Video Lectures
2016
Video lectures bring flexibility and enable distance learning in education. With the help of videos, educational organizations are able to serve a wider and more heterogeneous group of students. As streaming videos have become essential part of teaching in higher education, quality of service (QoS) issues should be taken more into consideration. However, systematic quality monitoring of video lecture delivery, to our knowledge, is rarely used in a way that would provide also the student with quality information. This paper describes our ongoing research on developing a streaming video quality evaluation tool integrated in a learning environment that our master’s students use. The tool serve…