2 resultados para geospatial data
em Helda - Digital Repository of University of Helsinki
Resumo:
This thesis presents novel modelling applications for environmental geospatial data using remote sensing, GIS and statistical modelling techniques. The studied themes can be classified into four main themes: (i) to develop advanced geospatial databases. Paper (I) demonstrates the creation of a geospatial database for the Glanville fritillary butterfly (Melitaea cinxia) in the Åland Islands, south-western Finland; (ii) to analyse species diversity and distribution using GIS techniques. Paper (II) presents a diversity and geographical distribution analysis for Scopulini moths at a world-wide scale; (iii) to study spatiotemporal forest cover change. Paper (III) presents a study of exotic and indigenous tree cover change detection in Taita Hills Kenya using airborne imagery and GIS analysis techniques; (iv) to explore predictive modelling techniques using geospatial data. In Paper (IV) human population occurrence and abundance in the Taita Hills highlands was predicted using the generalized additive modelling (GAM) technique. Paper (V) presents techniques to enhance fire prediction and burned area estimation at a regional scale in East Caprivi Namibia. Paper (VI) compares eight state-of-the-art predictive modelling methods to improve fire prediction, burned area estimation and fire risk mapping in East Caprivi Namibia. The results in Paper (I) showed that geospatial data can be managed effectively using advanced relational database management systems. Metapopulation data for Melitaea cinxia butterfly was successfully combined with GPS-delimited habitat patch information and climatic data. Using the geospatial database, spatial analyses were successfully conducted at habitat patch level or at more coarse analysis scales. Moreover, this study showed it appears evident that at a large-scale spatially correlated weather conditions are one of the primary causes of spatially correlated changes in Melitaea cinxia population sizes. In Paper (II) spatiotemporal characteristics of Socupulini moths description, diversity and distribution were analysed at a world-wide scale and for the first time GIS techniques were used for Scopulini moth geographical distribution analysis. This study revealed that Scopulini moths have a cosmopolitan distribution. The majority of the species have been described from the low latitudes, sub-Saharan Africa being the hot spot of species diversity. However, the taxonomical effort has been uneven among biogeographical regions. Paper III showed that forest cover change can be analysed in great detail using modern airborne imagery techniques and historical aerial photographs. However, when spatiotemporal forest cover change is studied care has to be taken in co-registration and image interpretation when historical black and white aerial photography is used. In Paper (IV) human population distribution and abundance could be modelled with fairly good results using geospatial predictors and non-Gaussian predictive modelling techniques. Moreover, land cover layer is not necessary needed as a predictor because first and second-order image texture measurements derived from satellite imagery had more power to explain the variation in dwelling unit occurrence and abundance. Paper V showed that generalized linear model (GLM) is a suitable technique for fire occurrence prediction and for burned area estimation. GLM based burned area estimations were found to be more superior than the existing MODIS burned area product (MCD45A1). However, spatial autocorrelation of fires has to be taken into account when using the GLM technique for fire occurrence prediction. Paper VI showed that novel statistical predictive modelling techniques can be used to improve fire prediction, burned area estimation and fire risk mapping at a regional scale. However, some noticeable variation between different predictive modelling techniques for fire occurrence prediction and burned area estimation existed.
Resumo:
In this paper, I look into a grammatical phenomenon found among speakers of the Cambridgeshire dialect of English. According to my hypothesis, the phenomenon is a new entry into the past BE verb paradigm in the English language. In my paper, I claim that the structure I have found complements the existing two verb forms, was and were, with a third verb form that I have labelled ‘intermediate past BE’. The paper is divided into two parts. In the first section, I introduce the theoretical ground for the study of variation, which is founded on empiricist principles. In variationist linguistics, the main claim is that heterogeneous language use is structured and ordered. In the last 50 years of history in modern linguistics, this claim is controversial. In the 1960s, the generativist movement spearheaded by Noam Chomsky diverted attention away from grammatical theories that are based on empirical observations. The generativists steered away from language diversity, variation and change in favour of generalisations, abstractions and universalist claims. The theoretical part of my paper goes through the main points of the variationist agenda and concludes that abandoning the concept of language variation in linguistics is harmful for both theory and methodology. In the method part of the paper, I present the Helsinki Archive of Regional English Speech (HARES) corpus. It is an audio archive that contains interviews conducted in England in the 1970s and 1980s. The interviews were done in accordance to methods used generally in traditional dialectology. The informants are mostly elderly male people who have lived in the same region throughout their lives and who have left school at an early age. The interviews are actually conversations: the interviewer allowed the informant to pick the topic of conversation to induce a maximally relaxed and comfortable atmosphere and thus allow the most natural dialect variant to emerge in the informant’s speech. In the paper, the corpus chapter introduces some of the transcription and annotation problems associated with spoken language corpora (especially those containing dialectal speech). Questions surrounding the concept of variation are present in this part of the paper too, as especially transcription work is troubled by the fundamental problem of having to describe the fluctuations of everyday speech in text. In the empirical section of the paper, I use HARES to analyse the speech of four informants, with special focus on the emergence of the intermediate past BE variant. My observations and the subsequent analysis permit me to claim that my hypothesis seems to hold. The intermediate variant occupies almost all contexts where one would expect was or were in the informants’ speech. This means that the new variant is integrated into the speakers’ grammars and exemplifies the kind of variation that is at the heart of this paper.