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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Sanakielet ja lokaalisuus
Get PDFIn this master's thesis we study the generalization of word languages into multi-dimensional arrays of letters i.e picture languages. Our main interest is the class of recognizable picture languages which has many properties in common with the robust class of regular word languages. After surveying the basic properties of picture languages, we present a logical characterization of recognizable picture languages—a generalization of Büchi's theorem of word languages into pictures, namely that the class of recognizable picture languages is the one recognized by existential monadic second-order logic. The proof presented is a recent one that makes the relation between tilings and logic clear in the proof. By way of the proof we also study the locality of the model theory of picture structures through logical locality obtained by normalization of EMSO on those structures.
A continuing theme in the work is also to compare automata and recognizability between word and picture languages. In the fourth section we briefly look at topics related to computativity and computational complexity of recognizable picture languages
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
On the retrieval of atmospheric profiles
No full textMeasurements of the Earth's atmosphere are crucial for understanding the behavior of the atmosphere and the underlying chemical and dynamical processes. Adequate monitoring of stratospheric ozone and greenhouse gases, for example, requires continuous global observations. Although expensive to build and complicated to operate, satellite instruments provide the best means for the global monitoring. Satellite data are often supplemented by ground-based measurements, which have limited coverage but typically provide more accurate data. Many atmospheric processes are altitude-dependent. Hence, the most useful atmospheric measurements provide information about the vertical distribution of the trace gases. Satellite instruments that observe Earth's limb are especially suitable for measuring atmospheric profiles. Satellite instruments looking down from the orbit, and remote sensing instruments looking up from the ground, generally provide considerably less information about the vertical distribution.
Remote sensing measurements are indirect. The instruments observe electromagnetic radiation, but it is ozone, for example, that we are interested in. Interpreting the measured data requires a forward model that contains physical laws governing the measurement. Furthermore, to infer meaningful information from the data, we have to solve the corresponding inverse problem. Atmospheric inverse problems are typically nonlinear and ill-posed, requiring numerical treatment and prior assumptions. In this work, we developed inversion methods for the retrieval of atmospheric profiles. We used measurements by Optical Spectrograph and InfraRed Imager System (OSIRIS) on board the Odin satellite, Global Ozone Monitoring by Occultation of Stars (GOMOS) on board the Envisat satellite, and ground-based Fourier transform spectrometer (FTS) at Sodankylä, Finland. For OSIRIS and GOMOS, we developed an onion peeling inversion method and retrieved ozone, aerosol, and neutral air profiles. From the OSIRIS data, we also retrieved NO2 profiles. For the FTS data, we developed a dimension reduction inversion method and used Markov chain Monte Carlo (MCMC) statistical estimation to retrieve methane profiles.
Main contributions of this work are the retrieved OSIRIS and GOMOS satellite data sets, and the novel retrieval method applied to the FTS data. Long satellite data records are useful for trends studies and for distinguishing between anthropogenic effects and natural variations. Before this work, GOMOS daytime ozone profiles were missing from scientific studies because the operational GOMOS daytime occultation product contains large biases. The GOMOS bright limb ozone product vastly improves the stratospheric part of the GOMOS daytime ozone. On the other hand, the dimension reduction method is a promising new technique for the retrieval of atmospheric profiles, especially when the measurement contains little information about the vertical distribution of gases.Ilmakehän mittaukset ovat tärkeitä, jotta ymmärtäisimme paremmin ilmakehään liittyviä kemiallisia ja dynaamisia prosesseja. Esimerkiksi otsonikerros ja kasvihuonekaasut ovat kohteita, jotka vaativat jatkuvaa ja koko maapallon kattavaa havainnointia. Satelliiteissa olevat mittalaitteet ovat yleensä hankalia totetuttaa ja kalliita, mutta tarjoavat parhaat mahdollisuudet tällaiseen havainnointiin. Satelliittimittauksia täydennetään usein maanpintamittauksilla, jotka ovat paikallisia mutta yleensä tarkkoja. Monet ilmakehän ilmiöt ovat tärkeitä vain tietyillä ilmakehän korkeuksilla. Siksi hyödyllisimmät mittalaitteet tuottavat tietoa kaasujen jakaumasta korkeuden suhteen. Satelliiteissa olevat mittalaitteet, jotka katsovat maan ilmakehän läpi avaruuteen tuottavat yleensä parasta tietoa ilmakehän pystyjakaumasta. Mittalaitteet, jotka katsovat ilmakehän läpi ylös maanpinnalta tai alas kiertoradalta soveltuvat huonommin pystyjakauman tutkimiseen.
Kaukokartoitusmittaukset ovat aina epäsuoria. Mittalaitteet havaitsevat sähkömagneettista säteilyä, mutta kiinnostava suure on esimerkiksi ilmakehän otsoni. Mittausten tulkinta vaatii ilmakehän säteilyn kulun mallintamista ja havaintoon liittyvän käänteisongelman ratkaisua. Ilmakehään liittyvät käänteisongelmat ovat yleensä epälineaarisia ja niiden ratkaisemiseen tarvitaan numeerisia menetelmiä ja ennakko-oletuksia. Tässä väitöstyössä kehitettiin menetelmiä ilmakehän kaasujen pystyjakaumien ratkaisemiseen. Työssä käytettiin Odin-satelliitissa olevaa OSIRIS-mittalaitetta (Optical Spectrograph and InfraRed Imager System) ja Envisat-satelliitissa olevaa GOMOS-mittalaitetta (Global Ozone Monitoring by Occultation of Stars). Lisäksi käytettiin Sodankylässä sijaitsevaa, maan pinnalla olevaa FTS-mittalaitetta. OSIRIS ja GOMOS -mittauksista ratkaistiin otsonin, aerosolien ja neutraali-ilman pitoisuuksia. OSIRIS-mittauksista ratkaistiin lisäksi NO2. FTS-mittauksista ratkaistiin metaanin pystyjakauma rajoittamalla ongelman tila-avaruutta ja käyttämällä hyväksi Markov chain Monte Carlo (MCMC) menetelmää.
Tämän väitöstyön tärkeimmät tulokset ovat pitkät OSIRIS ja GOMOS aikasarjat, sekä uusi käänteismenetelmä FTS-mittausten parempaan hyödyntämiseen. Pitkät mittaussarjat ovat tärkeitä ilmakehän muutoksen tutkimiseen ja ihmisen vaikutuksen erottamiseen luonnollisesta vaihtelusta. Tässä työssä kehitetty GOMOS-otsonituote on huomattavasti parempi kuin vanha, eri menetelmällä ratkaistu otsonituote. FTS-mittausten hyödyntämiseen kehitetty menetelmä on uusi ja lupaava tapa ratkaista pystyjakaumia mittauksista, joiden informaatiosisältö on rajoitettu.ei saavutettav
OSIRIS inversiomoduulin kehitys ja validointi
No full textOSIRIS on ruotsalaisessa Odin-satelliitissa oleva näkyvän ja UV-alueen spektrometri, joka mittaa keski-ilmakehästä sironnutta auringon säteilyä spektrialueella 280 - 800 nm.
Instrumentin spektraalinen resoluutio on noin 1 nm.
Mittauksista voidaan päätellä muutamien ilmakehän kaasujen pitoisuudet ratkaisemalla epäsuoriin mittauksiin liittyvä käänteisongelma.
Kaasuja, joita OSIRIS mittauksista voidaan havaita, ovat neutraali ilma, 03, NO2 ja aerosolit.
Tämän työn tarkoituksena on ollut kehittää edelleen Ilmatieteen laitoksella OSIRIS datan käänteismuunnoksen suorittavaa ohjelmaa.
Erityisesti tässä työssä on kehitetty NO2-profiilien ratkaisemista.
Tuloksia on verrattu kahden muun OSIRIS-dataa kääntävän algoritmin tuloksiin (DOAS ja Flittner), sekä toisen keski-ilmakehä mittauksia tekevän satelliitti-instrumentin (POAM III:n) mittauksiin.
Vertailuissa saatiin erittäin hyvä vastaavuus eri OSIRIS-inversioalgoritmien välille.
Keskiarvojen suhteellinen ero oli yleensä vähemmän kuin 5%.
OSIRIS ja POAM III NO2-vertailuissa havaittiin kuitenkin suuria eroja alle 25 km:n korkeuksilla, POAM III:n mitatessa systemaattisesti suurempia NO2 pitoisuuksia kuin OSIRIS.
Keskiarvojen suhteellinen ero oli suurimmillaan 22 km:n korkeudella (35%).
Vertailujen lisäksi työssä on tehty herkkyysanalyysejä simuloidulla datalla.
Ne osoittivat, että ylimpien kerroksien invertoidut otsoniarvot ovat suhteellisen herkkiä virheelliselle a priori tiedolle ilmakehän rakenteesta.
NO2-profiilit kääntyivät kuitenkin lähes täydellisesti oikein virheellisestä a priori tiedosta huolimatta
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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