First Observation of Vector Boson Pairs in a Hadronic Final State at the Tevatron Collider

We present the first observation in hadronic collisions of the electroweak production of vector boson pairs (VV, V=W, Z) where one boson decays to a dijet final state. The data correspond to 3.5  fb-1 of integrated luminosity of pp̅ collisions at √s=1.96  TeV collected by the CDF II detector at the Fermilab Tevatron. We observe 1516±239(stat)±144(syst) diboson candidate events and measure a cross section σ(pp̅ →VV+X) of 18.0±2.8(stat)±2.4(syst)±1.1(lumi)  pb, in agreement with the expectations of the standard model.

First Observation of Vector Boson Pairs in a Hadronic Final State at the Tevatron Collider

We present the first observation in hadronic collisions of the electroweak production of vector boson pairs (VV, V=W,Z) where one boson decays to a dijet final state . The data correspond to 3.5 inverse femtobarns of integrated luminosity of ppbar collisions at sqrt(s)=1.96 TeV collected by the CDFII detector at the Fermilab Tevatron. We observe 1516+/-239(stat)+/-144(syst) diboson candidate events and measure a cross section sigma(ppbar->VV+X) of 18.0+/-2.8(stat)+/-2.4(syst)+/-1.1(lumi) pb, in agreement with the expectations of the standard model.

“Empire is a state of mind” – Imagining Eurasia in Russia –

Työssäni tarkastelen venäläistä neo-euraasianistista liikettä ja tapoja joilla liikkeen aktivistit rakentavat Euraasiasta yhtenäistä kokonaisuutta ja imperiumia. Keskeisiä tutkimuskysymyksiäni ovat: Mikä imperiumi on ja mitkä ovat sen keskeisiä motivaatioita ja teemoja? Kuinka imperiumin idea rakentuu tai käsitetään ja tämän voi tulkita? Minkälaisia seurauksia voi tulkita heidän tavallaan Euraasia nähdä olevan? Materiaalina käytän haastatteluja, jotka on kerätty Moskovassa keväällä 2008, ja liikkeen kirjallisia tuotoksia (lehdet ja Internet -sivut). Neo-euraasianistisella liikkeellä tarkoitan tässä työssä Kansainvälistä Euraasianistista liikettä (Meždunarodnoe Evrazijskoe Dviženie) ja sen alahaaraa Euraasianistista Nuorisoliittoa (Evrazijskij Sojuz Molodëži). Liike perustettiin virallisesti 2003, mutta rakentaa vahvasti historiallista yhteyttä 1930 -luvun klassiseen eurasianismiin. Tämän lisäksi sen diskurssissa on paljon neuvostoliittolaisia, fasistisia, uuskonservatiivisia ja nationalistisia piirteitä. Liikkeen johtohahmo on filosofi-geopoliitikko Alexandr Dugin. Työn tausta-ajatuksena minua kiinnostaa etenkin nk. älymystön tai intelligenttien vaikutus nationalismiin tai sosiaalisia ryhmiä määrittelevien diskurssien kehitykseen ja muutokseen.Tarkastelen materiaalia diskurssianalyyttisesta näkökulmasta. Näen diskurssianalyysin sen tutkimisena, miten sosiaalista todellisuutta tuotetaan erilaisissa sosiaalisissa käytännöissä. Samalla näiden diskurssien tutkiminen, foucautlaisen perinteen myötä, tarkastelee kriittisesti niiden tuottamia (aktualisoituneita sekä potentiaalisia) valtasuhteita. Käytän työssäni myös Benedict Andersonin kuvitellun yhteisön (imagined communities) käsitettä, joka auttaa hahmottamaan tapaa, jolla tutkimuskohteeni rakentavat imperiumia yhteisönä. Aktivistien puheessa imperiumi (imperiâ) tulee esiin pääasiallisesti positiivisesti ja ”heidän omanaan,” kun taas termi imperialismi (imperializm) pääosin negatiivisena, liittyen etenkin keskeisenä vihollisena pidettyihin Yhdysvaltoihin. Esiin nousee monta toisiinsa liittyvää teemaa, jotka jaottelen viideksi pääteemaksi. Näistä tarkastelen lähemmin imperiumia ”kaikkien kansojen hyväntekijänä (poliittinen puoli)”, ulkoisen voiman lähteenä (historiallis-geopoliittinen puoli) sekä kollektiivisen subjektin luojana (imperialistis-nationalistinen puoli). Pyrin kontekstualisoimaan diskurssin ja tarkastelemaan tapoja, joilla se ammentaa motiiveja myös historiallis-kulttuurisista tavoista hahmottaa aluetta ja sen asukkaita. Käsittelen myös kansan, kansakunnan, etnoksen ja nationalismin käsitteitä ja sitä, miten ne nousevat neo-eurasianistisessa diskursissa esiin. Imperiaalisen nationalismin (imperskij nacionalizm) käsite auttaa ymmärtämään niitä tapoja, jolla liike tekee sekä pesäeroa nationalismiin että samalla hyödyntää monia nationalistisen diskurssin perusteemoja. Eräs liikkeen diskurssin keskeisistä eroista niin sanottuun nationalismin valtavirtaan on ”kansakunnan (naciâ)” käsitteen vahva negatiivinen konnotaatio. Sen vastakohtana esiin nostetaan vahvasti kansan (narod) käsite. Samalla kuitenkin etnisen venäläisen (russkij) käsitettä käytetään tavallista laajemmin ja kattavammin kuin tavallisesti, ja ennen kaikkea Venäjä nousee imperiumin keskeisimmäksi tekijäksi. Euraasialaiseen imperiumiin liitetyistä positiivistista mielikuvista käsittelen tarkemmin monikansallisuuden ja kansojen kodin ideaa, joka nousee mielestäni huomattavaksi retoriseksi taustaksi kaikessa materiaalissa. Tähän liittyy vahvasti myös saman teeman sivujuonne, eli imperiumin ”vapauttava” rooli. Tulkitsen, että liikkeen imperiumi -diskurssilla on instrumentaalinen luonne: se legitimoi aktivistien vaatimuksia varsinkin entisen Neuvostoliiton alueen suhteen. ”Euraasialaisen kansan” ajatus toimii mahdollisena Euraasiaa yhteisenä tekijänä ”Neuvostokansan” tilalla. Sen taustalla materiaalistani päätellen siintävät kuitenkin enemmänkin Venäjä ja venäläis -spesifit vaateet kuin koko Euraasia. Pohdin myös kansakunnan (nation) hyljeksimisen syitä ja käsitteen sopivuutta Venäjälle, kuten myös venäläisyyden käsitteiden kerrostuneisuutta. Kokonaisuudessaan imperiumi tuli esiin abstraktina, utopistisena ja ”totaalisena” kokonaisuutena.

On the charging state of atmospheric aerosols and ion-induced nucleation

Floating in the air that surrounds us is a number of small particles, invisible to the human eye. The mixture of air and particles, liquid or solid, is called an aerosol. Aerosols have significant effects on air quality, visibility and health, and on the Earth's climate. Their effect on the Earth's climate is the least understood of climatically relevant effects. They can scatter the incoming radiation from the Sun, or they can act as seeds onto which cloud droplets are formed. Aerosol particles are created directly, by human activity or natural reasons such as breaking ocean waves or sandstorms. They can also be created indirectly as vapors or very small particles are emitted into the atmosphere and they combine to form small particles that later grow to reach climatically or health relevant sizes. The mechanisms through which those particles are formed is still under scientific discussion, even though this knowledge is crucial to make air quality or climate predictions, or to understand how aerosols will influence and will be influenced by the climate's feedback loops. One of the proposed mechanisms responsible for new particle formation is ion-induced nucleation. This mechanism is based on the idea that newly formed particles were ultimately formed around an electric charge. The amount of available charges in the atmosphere varies depending on radon concentrations in the soil and in the air, as well as incoming ionizing radiation from outer space. In this thesis, ion-induced nucleation is investigated through long-term measurements in two different environments: in the background site of Hyytiälä and in the urban site that is Helsinki. The main conclusion of this thesis is that ion-induced nucleation generally plays a minor role in new particle formation. The fraction of particles formed varies from day to day and from place to place. The relative importance of ion-induced nucleation, i.e. the fraction of particles formed through ion-induced nucleation, is bigger in cleaner areas where the absolute number of particles formed is smaller. Moreover, ion-induced nucleation contributes to a bigger fraction of particles on warmer days, when the sulfuric acid and water vapor saturation ratios are lower. This analysis will help to understand the feedbacks associated with climate change.

Kalman Filter Algorithm for Rating and Prediction in Basketball

The Thesis presents a state-space model for a basketball league and a Kalman filter algorithm for the estimation of the state of the league. In the state-space model, each of the basketball teams is associated with a rating that represents its strength compared to the other teams. The ratings are assumed to evolve in time following a stochastic process with independent Gaussian increments. The estimation of the team ratings is based on the observed game scores that are assumed to depend linearly on the true strengths of the teams and independent Gaussian noise. The team ratings are estimated using a recursive Kalman filter algorithm that produces least squares optimal estimates for the team strengths and predictions for the scores of the future games. Additionally, if the Gaussianity assumption holds, the predictions given by the Kalman filter maximize the likelihood of the observed scores. The team ratings allow probabilistic inference about the ranking of the teams and their relative strengths as well as about the teams’ winning probabilities in future games. The predictions about the winners of the games are correct 65-70% of the time. The team ratings explain 16% of the random variation observed in the game scores. Furthermore, the winning probabilities given by the model are concurrent with the observed scores. The state-space model includes four independent parameters that involve the variances of noise terms and the home court advantage observed in the scores. The Thesis presents the estimation of these parameters using the maximum likelihood method as well as using other techniques. The Thesis also gives various example analyses related to the American professional basketball league, i.e., National Basketball Association (NBA), and regular seasons played in year 2005 through 2010. Additionally, the season 2009-2010 is discussed in full detail, including the playoffs.

Rate Control State-of-the-art Survey

The majority of Internet traffic use Transmission Control Protocol (TCP) as the transport level protocol. It provides a reliable ordered byte stream for the applications. However, applications such as live video streaming place an emphasis on timeliness over reliability. Also a smooth sending rate can be desirable over sharp changes in the sending rate. For these applications TCP is not necessarily suitable. Rate control attempts to address the demands of these applications. An important design feature in all rate control mechanisms is TCP friendliness. We should not negatively impact TCP performance since it is still the dominant protocol. Rate Control mechanisms are classified into two different mechanisms: window-based mechanisms and rate-based mechanisms. Window-based mechanisms increase their sending rate after a successful transfer of a window of packets similar to TCP. They typically decrease their sending rate sharply after a packet loss. Rate-based solutions control their sending rate in some other way. A large subset of rate-based solutions are called equation-based solutions. Equation-based solutions have a control equation which provides an allowed sending rate. Typically these rate-based solutions react slower to both packet losses and increases in available bandwidth making their sending rate smoother than that of window-based solutions. This report contains a survey of rate control mechanisms and a discussion of their relative strengths and weaknesses. A section is dedicated to a discussion on the enhancements in wireless environments. Another topic in the report is bandwidth estimation. Bandwidth estimation is divided into capacity estimation and available bandwidth estimation. We describe techniques that enable the calculation of a fair sending rate that can be used to create novel rate control mechanisms.

Search for the Higgs boson in the all-hadronic final state using the CDF II detector

We report on a search for the production of the Higgs boson decaying to two bottom quarks accompanied by two additional quarks. The data sample used corresponds to an integrated luminosity of approximately 4  fb-1 of pp̅ collisions at √s=1.96  TeV recorded by the CDF II experiment. This search includes twice the integrated luminosity of the previous published result, uses analysis techniques to distinguish jets originating from light flavor quarks and those from gluon radiation, and adds sensitivity to a Higgs boson produced by vector boson fusion. We find no evidence of the Higgs boson and place limits on the Higgs boson production cross section for Higgs boson masses between 100  GeV/c2 and 150  GeV/c2 at the 95% confidence level. For a Higgs boson mass of 120  GeV/c2, the observed (expected) limit is 10.5 (20.0) times the predicted standard model cross section.

Part-of-Speech Tagging using Parallel Weighted Finite-State Transducers

We use parallel weighted finite-state transducers to implement a part-of-speech tagger, which obtains state-of-the-art accuracy when used to tag the Europarl corpora for Finnish, Swedish and English. Our system consists of a weighted lexicon and a guesser combined with a bigram model factored into two weighted transducers. We use both lemmas and tag sequences in the bigram model, which guarantees reliable bigram estimates.

Finite-State Spell-Checking with Weighted Language and Error Models

In this paper we present simple methods for construction and evaluation of finite-state spell-checking tools using an existing finite-state lexical automaton, freely available finite-state tools and Internet corpora acquired from projects such as Wikipedia. As an example, we use a freely available open-source implementation of Finnish morphology, made with traditional finite-state morphology tools, and demonstrate rapid building of Northern Sámi and English spell checkers from tools and resources available from the Internet.