On Transmission System Design for Wireless Broadcasting

This thesis considers aspects related to the design and standardisation of transmission systems for wireless broadcasting, comprising terrestrial and mobile reception. The purpose is to identify which factors influence the technical decisions and what issues could be better considered in the design process in order to assess different use cases, service scenarios and end-user quality. Further, the necessity of cross-layer optimisation for efficient data transmission is emphasised and means to take this into consideration are suggested. The work is mainly related terrestrial and mobile digital video broadcasting systems but many of the findings can be generalised also to other transmission systems and design processes. The work has led to three main conclusions. First, it is discovered that there are no sufficiently accurate error criteria for measuring the subjective perceived audiovisual quality that could be utilised in transmission system design. Means for designing new error criteria for mobile TV (television) services are suggested and similar work related to other services is recommended. Second, it is suggested that in addition to commercial requirements there should be technical requirements setting the frame work for the design process of a new transmission system. The technical requirements should include the assessed reception conditions, technical quality of service and service functionalities. Reception conditions comprise radio channel models, receiver types and antenna types. Technical quality of service consists of bandwidth, timeliness and reliability. Of these, the thesis focuses on radio channel models and errorcriteria (reliability) as two of the most important design challenges and provides means to optimise transmission parameters based on these. Third, the thesis argues that the most favourable development for wireless broadcasting would be a single system suitable for all scenarios of wireless broadcasting. It is claimed that there are no major technical obstacles to achieve this and that the recently published second generation digital terrestrial television broadcasting system provides a good basis. The challenges and opportunities of a universal wireless broadcasting system are discussed mainly from technical but briefly also from commercial and regulatory aspect

Tunnuslukujen kerääminen GSM-siirtoverkon signaalin laadun mittauksessa

Tämän diplomityön aiheena oli toteuttaa signaalin laatua mittaavien tunnuslukujen keräämiseen tarkoitettu ohjelmisto Nokia GSM-siirtoverkkoon kuuluvista keskuksen päätelaitteista. Keräämiseen tarkoitettu ohjelmisto täydensi tukiasemaohjaimen tilastointijärjestelmään siten, että signaalin laatua kuvaavia tunnuslukuja saadaan nyt kerättyä keskitetysti koko tukiasemajärjestelmän siirtoyhteysverkosta. Signaalin laatua mittaavat tunnusluvut perustuvat kahden siirtolaitteen välisessä yhteydessä havaittuihin bittivirheisiin. Tunnuslukujen keräämisen kohteena olevat päätelaitteet voivat sijaita joko tukiasemaohjaimessa tai toisen sukupolven transkooderi submultipleksenssä. Molemmille tapauksille on toteutettu oma mittaustyyppi tilastointijärjestelmään. Tukiasemaohjaimen tilastointijärjestelmä koostuu mittausten hallintarajapinnasta, mittausten keskitetystä osasta sekä hajautetusta osasta. Kerätty tieto siirretään tilastointijärjestelmän keskitetystä osasta verkonhallintajärjestelmälle jälkikäsittelyä varten. Tässä diplomityössä on esitelty jälkikäsittelyn osa-alueita, joita ovat: turmeltuneiden näytteiden karsinta, tiivistäminen, ennustaminen, puuttuvien näytteiden estimointi sekä mittaustulosten esittäminen.

Tehokerroinkorjatun hakkuriteholähteen toteutusvaihtoehdot

Hyötysuhteen merkitys tehoelektroniikan järjestelmissä kasvaa jatkuvasti kun käytössä olevien järjestelmien määrä lisääntyy ja toisaalta energian hinta kallistuu. Hyötysuhteen lisäksi verkkovirran käyrämuotovaatimukset asettavat omat haasteensa sähköverkkoon liitettävien tehoelektroniikkajärjestelmien suunnittelulle. Tässä työssä tutkitaan häviöiden syntyyn vaikuttavia tekijöitä hakkuriteholähteissä ja pyritään löytämään keinoja hyötysuhteen parantamiseksi. Työssä analysoidaan 300 W – 2 kW tehoalueelle soveltuvat, tehokerroinkorjattujen AC/DC-hakkuriteholähteiden topologiavaihtoehdot ja arvioidaan niiden soveltuvuutta tavanomaisen boost-topologian korvaajaksi. Tarkastelussa otetaan huomioon kustannukset, toimivuus sekä saavutettu hyötysuhteen parantuminen verrattuna perinteisellä topologialla toteutettuun teholähteeseen. Tarkasteltavat topologiat valitaan kirjallisuustutkimuksen perusteella. Valittujen topologioiden häviöt ja hyötysuhde selvitetään analyyttisin menetelmin sekä simuloimalla. Käytännön testausta varten suunnitellaan ja rakennetaan prototyyppi valitusta topologiasta.

Use of the Optical Cantilever Microphone in Photoacoustic Spectroscopy

A novel cantilever pressure sensor was developed in the Department of Physics at the University of Turku in order to solve the sensitivity problems which are encountered when condenser microphones are used in photoacoustic spectroscopy. The cantilever pressure sensor, combined with a laser interferometer for the measurement of the cantilever movements, proved to be highly sensitive. The original aim of this work was to integrate the sensor in a photoacoustic gas detector working in a differential measurement scheme. The integration was made successfully into three prototypes. In addition, the cantilever was also integrated in the photoacoustic FTIR measurement schemes of gas-, liquid-, and solid-phase samples. A theoretical model for the signal generation in each measurement scheme was created and the optimal celldesign discussed. The sensitivity and selectivity of the differential method were evaluated when a blackbody radiator and a mechanical chopper were used with CO₂, CH4, CO, and C2H4 gases. The detection limits were in the sub-ppm level for all four gases with only a 1.3 second integration time and the cross interference was well below one percent for all gas combinations other than those between hydrocarbons. Sensitivity with other infrared sources was compared using ethylene as an example gas. In the comparison of sensitivity with different infrared sources the electrically modulated blackbody radiator gave a 35 times higher and the CO2-laser a 100 times lower detection limit than the blackbody radiator with a mechanical chopper. As a conclusion, the differential system is well suited to rapid single gas measurements. Gas-phase photoacoustic FTIR spectroscopy gives the best performance, when several components have to be analyzed simultaneously from multicomponent samples. Multicomponent measurements were demonstrated with a sample that contained different concentrations of CO₂, H₂O, CO, and four different hydrocarbons. It required an approximately 10 times longer measurement time to achieve the same detection limit for a single gas as with the differential system. The properties of the photoacoustic FTIR spectroscopy were also compared to conventional transmission FTIR spectroscopy by simulations. Solid- and liquid-phase photoacoustic FTIR spectroscopy has several advantages compared to other techniques and therefore it also has a great variety of applications. A comparison of the signal-to-noise ratio between photoacoustic cells with a cantilever microphone and a condenser microphone was done with standard carbon black, polyethene, and sunflower oil samples. The cell with the cantilever microphone proved to have a 5-10 times higher signal-to-noise ratio than the reference detector, depending on the sample. Cantilever enhanced photoacoustics will be an effective tool for gas detection and analysis of solid- and liquid-phase samples. The preliminary prototypes gave good results in all three measurement schemes that were studied. According to simulations, there are possibilities for further enhancement of the sensitivity, as well as other properties, of each system.

Kielikeskuksissa toimivien kieltenopettajien käsityksiä ja kokemuksia massayliopiston luomista haasteista

Challenges of mass university conceived and experienced by university language centre language teachers The massification of the university involved not only an expansion but also a transition from one period to another, from elite higher education to mass higher education. Massification cannot be viewed as expansion and structural change but it has to be viewed in a context of a number of changes involving universities, state, economy, society and culture as well as science, technology, education and research. In the Finnish academic context, massification is often associated with negative development and it may be used as an excuse for poor teaching. The objective of the present study is to find out how the mass context is manifested in the work of university language centre language teachers. The data were collected by means of semi-structured questionnaires from 32 language teachers working at language centres at the universities of Helsinki, Jyväskylä, Tampere and Turku in Finland. Both Finnish and native speakers, 6 male and 26 female teachers, were included. All the teachers in the study had taught more than 10 years. The data were complemented by interviews of four teachers and email data from one teacher. Phenomenographic analysis of the informants’ conceptions enabled a description of their experiences of students at a mass university, conceptions of teaching and learning and of issues related to work health. Some conceptions were consonant with earlier results. The conceptions revealed differences between two teacher groups, teachers of subject-specific language, or language for specific purposes (LSP), and teachers of elementary and advanced language courses (general language teachers). For the first, the conceptions of the investigated teachers provided a picture of the students as a member of a mass university. The students were seen as customers who demanded special services to facilitate their studies or were selective about the contents of the course. The finding that appeared only in the LSP teachers’ data was the unengaged attitude towards language study, which appeared as mere hunt for credits. On the other hand, the students were also seen as language learning individuals, but a clear picture of a truly interested language learner was evident in the data of general language teachers. The teachers’ conceptions of teaching and learning revealed a picture of experienced teachers with a long background of teaching, reflecting experiences from different time periods and influences from their own education and illustrating the increasing problems with organizing individual tutoring due to large, heterogeneous groups. It seemed, however, that in spite of the large student groups, general language teachers were able to support the students’ learning processes and to use learner-centred methods, whereas LSP teachers were frequently compelled to resort to knowledge transmission type of teaching. The conditions of the mass university were clearly manifested in the respondents’ conceptions about work satisfaction: there were a number of factors related to administration, teaching arrangements and the status of the language centres that were likely to add to the teachers’ work stress, whereas traditional characteristics of academic work were viewed as promoting work satisfaction. On the basis of the teachers’ conceptions, it is safe to assume that academic mass context and students’ orientations have an effect on the teacher’s approach to teaching, while there is no unequivocal association between mass university teaching and poor teaching.

Sähkönjakeluverkkoyhtiöiden kokemuksia liiketoiminnan taloudellisesta sääntelystä kolmannella valvontajaksolla 2012 - 2015

TIIVISTELMÄ Tekijä: Jouni Pyykkö Työn nimi: Sähkönjakeluverkkoyhtiöiden kokemuksia liiketoiminnan taloudellisesta sääntelystä kolmannella valvontajaksolla 2012 - 2015 Vuosi: 2014 Paikka: Hyvinkää Diplomityö. Lappeenrannan teknillinen yliopisto, Tuotantotalous. 115 sivua, 9 kuvaa, 2 taulukkoa Tarkastajat: Professori Timo Pihkala ja Tutkijatohtori Marita Rautiainen Hakusanat: Jakeluverkkoyhtiö, regulaatio ja sääntely Euroopan unionin 1990 -luvulla aloittama sähkömarkkinoiden kehittäminen on merkinnyt Suomessakin suuria muutoksia toimialan yrityksille. Sähköenergian kauppa ja tuotanto on saatettu vapaan markkinaehtoisen kilpailun piriin. Sen sijaan sähkönsiirron ja -jakelun liiketoiminnot on toteutettu alueellisten luonnollisten monopolien turvaamina liiketoimintamalleina. Monopolin kautta toteutettu liiketoiminta aiheuttaa merkittäviä eturistiriitoja sähkönjakeluverkkoliiketoiminnan sidosryhmille. Nämä ristiriidat voivat johtaa kuluttajan kannalta kohtuuttomaan sähkönsiirron hinnoitteluun. Toisaalta liiketoiminnan on turvattava jakeluverkkoyhtiölle riittävät kannusteet liiketoiminnan harjoittamiseen sekä turvata riittävät investointitasot sähköverkkoihin sähkönlaadun ja toimitusvarmuuden turvaamiseksi. Näiden eri sähkönjakeluliiketoiminnan sidosryhmien tarpeiden tasapainottamiseen käytetään Suomessa energiamarkkinaviranomaisen toteuttamaa verkkoyhtiöiden sääntelyä eli regulaatiota. Sääntelyn tavoitteena on turvata jakeluverkkoliiketoiminnan osapuolten ristiriitaiset edut niin, että kokonaisuuden aiheuttama hyvinvointitappio on mahdollisimman pieni. Tässä työssä tarkastellaan sääntelyn toimivuutta ja ongelmakohtia jakeluverkkoyhtiöiden liiketoiminnan näkökulmasta. Tutkimus on toteutettu haastattelemalla yhdeksää jakeluverkkoyhtiön edustajaa. Tavoitteena on löytää jakeluverkkoyhtiöiden näkökulmasta esiin nousevat sääntelyyn liittyvät ongelmat ja liiketoiminnan haasteet. Tutkielmassa luodaan myös kuvaus keskeisistä valvontamenetelmistä sekä toimenpiteistä, joilla jakeluverkkoyhtiöiden näkökulmasta sääntelymallia voisi parantaa ja tehostaa.

Synchronous Digital Hierarchy implementation to a Radio Transmission Node

Kiristyville markkinoille on aina tuotava jotain uutta tarjottavaa ja SDH-kortti on yksi sellainen tuote jonka Nokia Networks julkistaa osaksi uutta Nokia Flexihub Nodea. Tavoitteena on suunnitella VC-12kanavoitu STM-1 kortti yhdistämään ylemmän tason tietoliikenneverkko suuren kapasiteetin radioon. Ennen kuin markkinoilla on valmis tuote, on sen takana valtaisa määrä työtä. Erilaisia dokumentteja on pitänyt tuottaa ja sopimuksia tehdä. Esimerkiksi vaatimusmäärittelyt on oltava selvät, jotta tiedetään mitä tuotteelta halutaan. Tätä ennen on kuitenkin pitänyt ymmärtää miten SDHtoimii ja miten otsikkotavuja käsitellään. Myös erilaiset piirivalinnat aiheuttavat miettimistä, sillä markkinoilla on runsaasti valmiita piirejä SDH signaalinkäsittelyyn. Varma tiedonsiirto on tärkeää puhelinoperaattorille ja siksi joudutaan miettimään varmennuksia ja niiden toteuttamista. Myös synkronointi on tärkeä osa SDH järjestelmää ja sen toteuttaminen hyvin on tärkeää. Hälytykset on otettava huomioon ja mietittävä, miten niiden käsittely saadaan hoidettua järkevästi, ilman että mikään järjestelmän osa ruuhkautuu kohtuuttomasti. Tässä Diplomityössä on tutustuttu SDH-järjestelmään, otsikkotavujen käsittelyyn ja vaatimusmäärittelyihin.

Transonic flow past on enlarged missile nose parts

Numerical computation of a viscid heat-conducting transonic flow over a generic commercial rocket profile with symmetric oversized nose part was carried out. It has been shown that at zero angle of attack for some free-streamvelocity value flow pattern loses its symmetry. This results in non-uniform pressure distribution on rocket surface in angle direction which may yield in additional oscillating stress on the rocket. Also it has been found that obtained non-symmetric flow patterns are stable for small velocity perturbations.

Cardiovascular effects of short term exposure to electric and magnetic fields of electricity power transmission

In the electrical industry the 50 Hz electric and magnetic fields are often higher than in the average working environment. The electric and magnetic fields can be studied by measuring or by calculatingthe fields in the environment. For example, the electric field under a 400 kV power line is 1 to 10 kV/m, and the magnetic flux density is 1 to 15 µT. Electricand magnetic fields of a power line induce a weak electric field and electric currents in the exposed body. The average current density in a human being standing under a 400 kV line is 1 to 2 mA/m2. The aim of this study is to find out thepossible effects of short term exposure to electric and magnetic fields of electricity power transmission on workers' health, in particular the cardiovascular effects. The study consists of two parts; Experiment I: influence on extrasystoles, and Experiment II: influence on heart rate. In Experiment I two groups, 26 voluntary men (Group 1) and 27 transmission-line workers (Group 2), were measured. Their electrocardiogram (ECG) was recorded with an ambulatory recorder both in and outside the field. In Group 1 the fields were 1.7 to 4.9 kV/m and 1.1 to 7.1 pT; in Group 2 they were 0.1 to 10.2 kV/m and 1.0 to 15.4 pT. In the ECG analysis the only significant observation was a decrease in the heart rate after field exposure (Group 1). The drop cannot be explained with the first measuring method. Therefore Experiment II was carried out. In Experiment II two groups were used; Group 1 (26 male volunteers) were measured in real field exposure, Group 2 (15 male volunteers) in "sham" fields. The subjects of Group 1 spent 1 h outside the field, then 1 h in the field under a 400 kV transmission line, and then again 1 h outside the field. Under the 400 kV linethe field strength varied from 3.5 to 4.3 kV/m, and from 1.4 to 6.6 pT. Group 2spent the entire test period (3 h) in a 33 kV outdoor testing station in a "sham" field. ECG, blood pressure, and electroencephalogram (EEG) were measured by ambulatory methods. Before and after the field exposure, the subjects performed some cardiovascular autonomic function tests. The analysis of the results (Experiments I and II) showed that extrasystoles or arrythmias were as frequent in the field (below 4 kV/m and 4 pT) as outside it. In Experiment II there was no decrease detected in the heart rate, and the systolic and diastolic blood pressure stayed nearly the same. No health effects were found in this study.

Electrical Machine Product Development; Transmission to Lean Approach

The requirements set by the market for electrical machines become increasingly demanding requiring more sophisticated technological solutions. Companies producing electrical ma-chines are challenged to develop machines that provide competitive edge for the customer for example through increased efficiency, reliability or some customer specific special requirement. The objective of this thesis is to derive a proposal for the first steps to transform the electrical machine product development process of a manufacturing company towards lean product development. The current product development process in the company is presented together with the processes of four other companies interviewed for the thesis. On the basis of current processes of the electrical machine industry and the related literature, a generalized electrical machine product development process is derived. The management isms and –tools utilized by the companies are analyzed. Adoption of lean Pull-Event –reviews, Oobeya –management and Knowledge based product development are suggested as the initial steps of implementing lean product development paradigm in the manufacturing company. Proposals for refining the cur-rent product development process and increasing the stakeholder involvement in the development projects are made. Lean product development is finding its way to Finnish electrical machine industry, but the results will be available only after the methods have been implemented and adopted by the companies. There is some enthusiasm about the benefits of lean approach and if executed successfully it will provide competitive edge for the Finnish electrical machine industry.