Multifrequency VLBI Observations of Selected Active Galactic Nuclei

In this dissertation, active galactic nuclei (AGN) are discussed, as they are seen with the high-resolution radio-astronomical technique called Very Long Baseline Interferometry (VLBI). This observational technique provides very high angular resolution (_ 10−300 = 1 milliarcsecond). VLBI observations, performed at different radio frequencies (multi-frequency VLBI), allow to penetrate deep into the core of an AGN to reveal an otherwise obscured inner part of the jet and the vicinity of the AGN’s central engine. Multi-frequency VLBI data are used to scrutinize the structure and evolution of the jet, as well as the distribution of the polarized emission. These data can help to derive the properties of the plasma and the magnetic field, and to provide constraints to the jet composition and the parameters of emission mechanisms. Also VLBI data can be used for testing the possible physical processes in the jet by comparing observational results with results of numerical simulations. The work presented in this thesis contributes to different aspects of AGN physics studies, as well as to the methodology of VLBI data reduction. In particular, Paper I reports evidence of optical and radio emission of AGN coming from the same region in the inner jet. This result was obtained via simultaneous observations of linear polarization in the optical and in radio using VLBI technique of a sample of AGN. Papers II and III describe, in detail, the jet kinematics of the blazar 0716+714, based on multi-frequency data, and reveal a peculiar kinematic pattern: plasma in the inner jet appears to move substantially faster that that in the large-scale jet. This peculiarity is explained by the jet bending, in Paper III. Also, Paper III presents a test of the new imaging technique for VLBI data, the Generalized Maximum Entropy Method (GMEM), with the observed (not simulated) data and compares its results with the conventional imaging. Papers IV and V report the results of observations of the circularly polarized (CP) emission in AGN at small spatial scales. In particular, Paper IV presents values of the core CP for 41 AGN at 15, 22 and 43 GHz, obtained with the help of the standard Gain transfer (GT) method, which was previously developed by D. Homan and J.Wardle for the calibration of multi-source VLBI observations. This method was developed for long multi-source observations, when many AGN are observed in a single VLBI run. In contrast, in Paper V, an attempt is made to apply the GT method to single-source VLBI observations. In such observations, the object list would include only a few sources: a target source and two or three calibrators, and it lasts much shorter than the multi-source experiment. For the CP calibration of a single-source observation, it is necessary to have a source with zero or known CP as one of the calibrators. If the archival observations included such a source to the list of calibrators, the GT could also be used for the archival data, increasing a list of known AGN with the CP at small spatial scale. Paper V contains also calculation of contributions of different sourced of errors to the uncertainty of the final result, and presents the first results for the blazar 0716+714.

Service oriented archive based on Fedora Commons

Presentation at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014

A Distributed Microservices Framework Integrating Taverna

Presentation at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014

SimpleREST -RESTful DSpace API

Poster at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014

Prospects of Bitcoin diffusion

Currency is something people deal with every day in their lives. The contemporary society is very much revolving around currencies. Even though technological development has been rapid, the principle of currency has stayed relatively unchanged for a long time. Bitcoin is a digital currency that introduced an alternative to other digital currencies, and to the traditional physical currencies. Bitcoin is peer-to-peer, open source, and it erases the need of a third party in transactions. Bitcoin has since inception gained certain fame, but it has not established itself as a common currency in the world. The purpose of this study was to analyse what kind of potential does Bitcoin have to become a widely accepted currency in day-to-day transactions. The main research question was divided into three sub questions: • What kind of a process is the diffusion of new innovations? • What kinds of factors speak for the wider adoption of Bitcoin? • What kinds of factors speak against the wider adoption of Bitcoin? The purpose of the study was approached by having diffusion of innovations as the theoretical framework. The four elements in diffusion of innovations are, innovation, communication, time, and social system. The theoretical framework is applied to Bitcoin, and the research questions answered by analysing Bitcoin’s potential diffusion prospects. The body of research data consisted of media texts and statistics. In this study, content analysis was the research method. The main findings of the study are that Bitcoin has clear strengths, but it faces a large amount of uncertainty. Bitcoin’s strong areas are the transactions. They are fast, easy, and cheap. From the innovation diffusion perspective Bitcoin is still relatively unknown, and the general public’s attitudes towards it are sceptical. The research findings purport that Bitcoin has potential demand especially when the financial system of a region is dysfunctional, or when there is a financial crisis. Bitcoin is not very trusted, and the majority of people do not see a reason to start using Bitcoin in the future. A large number of people associate it with illegal activities. In general people are largely unaware of what Bitcoin is or what are the strengths and weaknesses. Bitcoin is an innovative alternative currency. However, unless people see a major need for Bitcoin due to a financial crisis, or dysfunctionality in the financial system, Bitcoin will not become much more widespread as it is today. Bitcoin’s underlying technology can be harnessed to multiple uses. Developments in that field in the future are something that future researchers could look into.

Juridisen kaksinkertaisen verotuksen problematiikka kansainvälisessä yritystoiminnassa

Tässä tutkielmassa tarkastellaan kansainvälisessä yritystoiminnassa esiintyviä juridisen kaksinkertaisen verotuksen ongelmatilanteita suomalaisten yritysten näkökulmasta. Tutkielmassa pohditaan lisäksi yritysten omaa roolia osana kaksinkertaisen verotuksen tilanteita. Juridista kaksinkertaista verotusta muodostuu, kun sama yhtiö maksaa samasta tulosta veroa kahteen valtioon. Teoriaosio etenee verotusoikeuden määrittämisestä kaksinkertaisen verotuksen muodostumiseen. Kaksinkertainen verotus pyritään poistamaan poistomenetelmällä, joka on Suomessa tavallisesti hyvitysmenetelmä. Ongelmatilanne muodostuu, kun kaksinkertaista verotusta ei saada tehokkaasti poistettua tulon lähdevaltion ja yhtiön asuinvaltion välillä. Tämä tutkielma on laadullinen tutkimus ja tutkimusmenetelmänä on käytetty teemahaastattelua. Tutkimustulokset osoittavat, että kvalifikaatiokonflikteissa juridisen kaksinkertaisen verotuksen ongelmatilanne esiintyy pääsääntöisesti rojalti-liiketulo -luokitteluristiriidan seurauksena. Kiinteän toimipaikan kvalifikaatio on harvinaisempi ongelmatilanne. Hyvitysmenetelmän suurimmat ongelmat esiintyvät puolestaan pääliikkeen tappiollisen liiketoiminnan johdosta. Toinen hyvitysmenetelmän ongelmakohta esiintyy, kun lähdeveron alainen tulo huomioidaan bruttotulosta, mutta ulkomaisen tulon hyvitys suoritetaan nettotulosta. Haastatteluiden perusteella on selvää, että yritysten oma rooli kaksinkertaisen verotuksen ehkäisyssä on merkittävä. Yrityksen omia vaikutusmahdollisuuksia ovat muun muassa riittävä ennakointikyky, dokumentointi, selkeät sopimukset ja asiantuntijuus.