104 research outputs found

    Imperial College Computing Student Workshop

    Get PDF

    2016-17 Graduate Bulletin

    Get PDF
    After 2003 the University of Dayton Bulletin went exclusively online. This copy was downloaded from the University of Dayton\u27s website in March 2018.https://ecommons.udayton.edu/bulletin_grad/1047/thumbnail.jp

    2017-18 Graduate Bulletin

    Get PDF
    After 2003 the University of Dayton Bulletin went exclusively online. This copy was downloaded from the University of Dayton\u27s website in March 2018.https://ecommons.udayton.edu/bulletin_grad/1048/thumbnail.jp

    2014-15 Graduate Bulletin

    Get PDF
    After 2003 the University of Dayton Bulletin went exclusively online. This copy was downloaded from the University of Dayton\u27s website.https://ecommons.udayton.edu/bulletin_grad/1009/thumbnail.jp

    2015-16 Graduate Bulletin

    Get PDF
    After 2003 the University of Dayton Bulletin went exclusively online. This copy was downloaded from the University of Dayton\u27s website in March of 2018. Please note: Even though this copy says draft it is the final copy.https://ecommons.udayton.edu/bulletin_grad/1046/thumbnail.jp

    Puistute takseertunnuste hindamine aerolidari mÔÔtmisandmete pÔhjal hemiboreaalsetes metsades

    Get PDF
    A Thesis for applying for the degree of Doctor of Philosophy in Forestry.Forest management and planning requires up-to-date data, which commonly is acquired using field experts and ground measurements. Nowadays, more and more of data about forest stands is measured using remotely sensing methods. Most common methods include aerial photography and laser scanning from airplanes, also spectral measurements from satellites or even drone images and applications. This doctoral thesis focuses on developing applications and methods for utilising the airborne laser scanning (ALS) data that is freely available for the whole Estonia. The ALS measurements are carried out by the Estonian Land Board on a routine basis twice a year – in spring and summer. The first variable that was studied in this thesis was forest height. Based on the thesis, the most reliable method for forest height assessment was using the ALS point-cloud 80th height percentile (HP80). The small circular plot (radius of 15
30 m) and stand based studies showed high correlations with the field-measured forest heights and with great confidence it can be said, that ALS-based forest height estimations are close or even with higher accuracy, than field inspected. The second studied variable was standing wood volume. The ALS-based methods and models that were developed throughout this thesis used the idea, that standing wood volume is based on forest height and density. For this the HP80 and a threshold-based point count ratio was used (canopy cover - CC). ALS-based CC (CCALS) estimates were studied and compared with digital hemispherical photo based measurements. The results showed similar errors as were shown in other similar studies, with around 10-15% root mean square error (RMSE). The strongest correlation was shown using all echoes above a 1.3 metre threshold. Combining the CCALS and HP80 showed standing wood volume estimates with a similar error as we would receive from field measurements (<20%). The freely available multitemporal ALS data showed promising results for forest height growth monitoring and detecting small-scale disturbances. CCALS was shown to have strong predictive value, when compared with a four year difference in thinned and unthinned stands. The nation-wide ALS data can also be combined with forest height predictions from satellites, providing a faster update compared to the ALS data. Promising results were shown using the interferometric synthetic aperture radar (InSAR). Stand species maps generated using self-learning algorithms and satellite based spectral data can be used for developing species specific models of standing wood volume prediction. By combining these different datasets we can construct a nation-wide forest resource to help make better decisions for forest management and targeting fieldwork.Metsades majandamisotsuste langetamiseks ja metsamajanduslike tööde planeerimiseks on metsaomanikel vaja andmeid. HarjumuspĂ€raselt on andmete kogumiseks tehtud metsas maapealseid mÔÔtmisi. Viimastel aastakĂŒmnetel on metsade inventeerimiseks ĂŒha enam aga kasutatud mittekontaktseid mÔÔtmisi - lennukitelt tehtavad aerofotosid, laserskaneerimist, satelliitidelt tehtavaid kiirgusmÔÔtmisi vĂ”i viimastel aastatel ka droonidelt tehtud pilte. Antud doktoritöö on vĂ”tnud fookusesse aerolaserskaneerimise (ALS) andmete pĂ”hjal Eesti metsadesse sobilike rakenduste vĂ€ljatöötamise. ALS mÔÔtmisi teeb Eesti Maa-amet rutiinsete lendude kĂ€igus kaks korda aastas, nii kevadel kui ka suvel. Aastast 2008 alustatud mÔÔtmiste tulemusel on Eesti ĂŒks vĂ€heseid riike maailmas, kus on vabalt kasutada mitmekordselt kogu riiki kattev ALS andmestik. Doktoritöö tulemusel töötati vĂ€lja metsa kĂ”rguse hindamiseks sobilikud meetodid, kasutades selleks punktipilvede kĂ”rgusprotsentiile. Tugevamaid seoseid metsas proovitĂŒkkidel mÔÔdetud kĂ”rgustega nĂ€itas punktipilve 80-protsentiil (HP80) ja uuringute pĂ”hjal vĂ”ib vĂ€ita, et metsa kĂ”rguse mÀÀramine suvistelt aerolidari andmetelt on ligilĂ€hedane tĂ€psustele, mida saadakse metsas kohapeal mÔÔtes. Teine oluline tunnus, mida metsade majandamise planeerimisel silmas peetakse, on kasvava metsa tagavara. Teadustöö pĂ”hjal töötati vĂ€lja mudelite kujud ja metoodika, mille abil prognoositud tagavara oli sarnase veapiiriga, mis on lubatud metsas hinnanguid tegevatele taksaatoritele (<20%). VĂ€ljatöötatud ALS-pĂ”hine mudeli kuju jĂ€rgib loogikat, et metsa tagavara on otseselt seotud mÔÔdetud kĂ”rguse ja metsa tihedusega. Tihenduse hindamiseks aerolidari andmetelt kasutatakse nivoopĂ”hist punktide suhtearvu ehk nn katvushinnangut (CCALS). Katvushinnangu tĂ€psuse valideerimiseks ja tihedas metsas sobiva prognoosimeetodi vĂ€ljatöötamiseks tehti vĂ€limÔÔtmisi kasutades poolsfÀÀrikaameraid. PoolsfÀÀripiltide pĂ”hjal tehtud valideerimise tulemused andsid sarnaseid veahinnanguid, mida on ka varasemates teadusuuringutes esitletud (RMSE = 10
15%). Kahe sarnasest fenoloogilisest perioodist ALS andmestiku lahutamisel uuriti ka muutuste tuvastamise vĂ”imalikkust. Uuringud andsid paljulubavaid tulemusi metsade kĂ”rguskasvu hindamiseks ja CCALS osutus ka oluliseks tunnuseks vĂ€iksemate hĂ€iringute, nagu nĂ€iteks harvendusraie, tuvastamiseks. Kogu riiki katva ALS andmestiku kombineerimisel erinevate satelliitandmetega vĂ”i nĂ€iteks spektraalsete mÔÔtmiste pĂ”hjal tehtud puistu liigiliste koosseisu kaartidega on vĂ”imalik antud töös vĂ€lja pakutud meetodite abil anda igal aastal kogu Eesti metsaressursside ĂŒlevaade. Samuti on vĂ”imalik koostada vaid kaugseirevahendeid ja proovitĂŒkkidel lĂ€hendatud mudeleid kasutades eraldiste pĂ”hised takseerkirjeldused, mida siis taksaatorid saavad nĂ€iteks kasutada oma vĂ€litööde kavandamisel.  Publication of this thesis is supported by the Estonian University of Life Sciences

    NASA Tech Briefs, April 1993

    Get PDF
    Topics include: Optoelectronics; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences; Life Sciences

    Head-Driven Phrase Structure Grammar

    Get PDF
    Head-Driven Phrase Structure Grammar (HPSG) is a constraint-based or declarative approach to linguistic knowledge, which analyses all descriptive levels (phonology, morphology, syntax, semantics, pragmatics) with feature value pairs, structure sharing, and relational constraints. In syntax it assumes that expressions have a single relatively simple constituent structure. This volume provides a state-of-the-art introduction to the framework. Various chapters discuss basic assumptions and formal foundations, describe the evolution of the framework, and go into the details of the main syntactic phenomena. Further chapters are devoted to non-syntactic levels of description. The book also considers related fields and research areas (gesture, sign languages, computational linguistics) and includes chapters comparing HPSG with other frameworks (Lexical Functional Grammar, Categorial Grammar, Construction Grammar, Dependency Grammar, and Minimalism)
    • 

    corecore