Phase voltage control and filtering in a converter-fed single-phase customer-end system of the LVDC distribution network

In recent years, the network vulnerability to natural hazards has been noticed. Moreover, operating on the limits of the network transmission capabilities have resulted in major outages during the past decade. One of the reasons for operating on these limits is that the network has become outdated. Therefore, new technical solutions are studied that could provide more reliable and more energy efficient power distributionand also a better profitability for the network owner. It is the development and price of power electronics that have made the DC distribution an attractive alternative again. In this doctoral thesis, one type of a low-voltage DC distribution system is investigated. Morespecifically, it is studied which current technological solutions, used at the customer-end, could provide better power quality for the customer when compared with the current system. To study the effect of a DC network on the customer-end power quality, a bipolar DC network model is derived. The model can also be used to identify the supply parameters when the V/kW ratio is approximately known. Although the model provides knowledge of the average behavior, it is shown that the instantaneous DC voltage ripple should be limited. The guidelines to choose an appropriate capacitance value for the capacitor located at the input DC terminals of the customer-end are given. Also the structure of the customer-end is considered. A comparison between the most common solutions is made based on their cost, energy efficiency, and reliability. In the comparison, special attention is paid to the passive filtering solutions since the filter is considered a crucial element when the lifetime expenses are determined. It is found out that the filter topology most commonly used today, namely the LC filter, does not provide economical advantage over the hybrid filter structure. Finally, some of the typical control system solutions are introduced and their shortcomings are presented. As a solution to the customer-end voltage regulation problem, an observer-based control scheme is proposed. It is shown how different control system structures affect the performance. The performance meeting the requirements is achieved by using only one output measurement, when operating in a rigid network. Similar performance can be achieved in a weak grid by DC voltage measurement. An additional improvement can be achieved when an adaptive gain scheduling-based control is introduced. As a conclusion, the final power quality is determined by a sum of various factors, and the thesis provides the guidelines for designing the system that improves the power quality experienced by the customer.

Centralized Motion Control of a Linear Tooth Belt Drive: Analysis of the Performance and Limitations

A centralized robust position control for an electrical driven tooth belt drive is designed in this doctoral thesis. Both a cascaded control structure and a PID based position controller are discussed. The performance and the limitations of the system are analyzed and design principles for the mechanical structure and the control design are given. These design principles are also suitable for most of the motion control applications, where mechanical resonance frequencies and control loop delays are present. One of the major challenges in the design of a controller for machinery applications is that the values of the parameters in the system model (parameter uncertainty) or the system model it self (non-parametric uncertainty) are seldom known accurately in advance. In this thesis a systematic analysis of the parameter uncertainty of the linear tooth beltdrive model is presented and the effect of the variation of a single parameter on the performance of the total system is shown. The total variation of the model parameters is taken into account in the control design phase using a Quantitative Feedback Theory (QFT). The thesis also introduces a new method to analyze reference feedforward controllers applying the QFT. The performance of the designed controllers is verified by experimentalmeasurements. The measurements confirm the control design principles that are given in this thesis.

Henkilökohtainen on poliittista. Neuvottelu politiikan sukupuolittuneesta työnjaosta Annan julkaisemissa poliitikkojen henkilökuvissa vuosina 1975–2005

Henkilökohtainen on poliittista Tutkimuksessa tarkastellaan tiedotusvälineissä käytyä neuvottelua miesten ja naisten mahdollisuuksista osallistua politiikkaan sekä siinä ilmenevää suomalaisen poliittisen julkisuuden muutosta. Tutkimuksen materiaalin muodostavat Anna-lehdessä vuosina 1975–2005 julkaistut 339 poliitikkojen henkilökuvaa, joita eritellään laadullisen tekstianalyysin keinoin. Politiikan sukupuolittunut työnjako Poliitikkojen henkilökuvat ovat Anna-lehdessä olleet henkilöhaastatteluja tai poliitikon haastatteluita yhdessä puolisonsa tai perheensä kanssa. Tutkittuna ajanjaksona Annassa on julkaistu selvästi enemmän naispoliitikkojen kuin miespoliitikkojen henkilökuvia. Poliitikkojen haastatteluissa neuvottellaan siitä, keillä on oikeus toimia politiikassa ja millaista politiikkaa miehet ja naiset voivat tehdä. Vaikka Annassa ilmestyneissä poliitikkojen henkilökuvissa on eri aikoina vastattu näihin kysymyksiin erilaisin tavoin, sukupuolittunut jako miesten yhteiskunnalliseen ja naisten yksityiseen tilaan säilyy teksteissä läpi koko tarkastellun 30 vuoden ajanjakson. Sukupuolittunut jako yhteiskunnalliseen ja yksityiseen ilmenee henkilökuvissa siten, että miehet esitetään toimimassa politiikassa vaivattomasti ja luonnollisesti, mutta naisten kuvataan ponnistelevan sen eteen, että he kykenisivät osallistumaan politiikkaan. Naispoliitikkojen henkilökuvissa toistuva kysymys on, millä edellytyksin tai millaisin rajoituksin naiset ovat voineet toimia politiikassa. Miehet edustavat poliitikon normia ja naiset poikkeusta normista. Poliitikkojen parisuhde- ja perhehaastatteluissa puolestaan käsitellään kysymystä sukupuolten välisestä työnjaosta perheessä. Kirjoituksissa toistuvat kysymykset siitä, millainen tulisi olla poliitikon ja hänen puolisonsa välinen työnjako, tulisiko miespoliitikon vaimon osallistua pyyteettömästi puolison uran tukemiseen tai millä tavoin naispoliitikon puolison tulisi suhtautua vaimonsa aikaa vievään poliittiseen uraan. Naispoliitikkojen haasteita Annan julkaisemat naispoliitikkojen henkilökuvat osoittavat sekä naisten poliittiseen osallistumiseen liittyviä ongelmia että joukon erilaisia ratkaisuja niihin. Naisten ruumiillisuus on näistä haasteista keskeisin. 1970-luvun Annassa ilmestyneissä naispoliitikkojen haastatteluissa käsiteltiin toistuvasti sitä, millä tavoin politiikassa työskentelevät naiset pukeutuvat, syövät ja lepäävät. 1980-luvulla Anna pyrki tekemään naisruumiista voimavaran osoittamalla, että naisten ”luonteva” taipumus hoivaamiseen teki heistä erityisen sopivia politiikan ”pehmeiden” asioiden puolestapuhujina, kuten rauhantyön ja sosiaalisektorin asioiden hoitajina. 1980-luvun lopussa ja 1990-luvun alussa julkaistuissa teksteissä luotiin naisten poliittista yhteisöllisyyttä korostamalla heidän kokemaansa ruumiillisuuteen perustuvaa sortoa, esimerkiksi ulkonäköön liittyviä epäasiallisia huomautuksia. 2000-luvulla naispoliitikkojen henkilökuvissa vakuutettiin, että naisen ikääntyminen ei heikennä hänen kykyään tehdä politiikkaa. Samana aikakautena julkaistuissa nuorehkojen naispoliitikkojen henkilökuvissa ruumiillisuuteen otettiin toinen näkökulma. Niissä naisruumiin väitetty sopimattomuus poliittiseen työhön ratkaistiin korostamalla, että haastatellut naiset kontrolloivat ruumistaan täydellisesti. Toinen naispoliitikkojen poliittista osallistumista uhkaavana tai häiritsevänä esitetty seikka Annassa on ollut yksityiselämä. Lehden mukaan kodin, puolison ja lasten yhdistäminen menestyksekkääseen poliittiseen uraan on ollut erityisen vaikeaa. 1980-luvun loppuun saakka henkilökuviin rakennettiin asetelma, jossa naispoliitikkojen tuli valita työn tai perheen välillä. Vuosituhannen taitteessa Anna otti yksityiselämän ja julkisen elämän väliseen ristiriitaan uuden näkökulman: lehti alkoi esittää, että lapset ovat naispoliitikkojen työelämän voimavara. Kirjoitusten mukaan tehokkaat nuoret naispoliitikot kykenivät halutessaan olemaan sekä ”pullantuoksuisia” äitejä että menestyviä poliitikkoja. Samalla kirjoitukset kuitenkin epäsuorasti osoittivat, ettei yksityisen ja julkisen elämän ristiriita kadonnut naispoliitikkojen kuvauksista: se vain muutti muotoaan ja sai uuden ratkaisun. Miespoliitikkojen luontevana esitetty asiantuntemus Annassa julkaistut miespoliitikkojen haastattelut ovat läpi tutkitun ajanjakson uusintaneet mielikuvaa yhteiskunnallisesta tilasta miehille luontaisesti sopivana ympäristönä. Niissä puhutaan politiikasta ikään kuin se olisi ainoastaan miesten hallitsema elämänpiiri. Poliitikka näyttäytyy miesten välisen kamppailun ja veljeyden kenttänä. Henkilökuvissa miespoliitikot pyrkivät kukistamaan vastustajansa, mutta samalla menestys miesten maailmassa edellyttää muiden miesten hyväksyntää. Henkilökuvissa rakennetaan vahvasti käsitystä miespoliitikoista yhteiskunnallisina asiantuntijoina. Kirjoituksissa heille annetaan tilaa ja mahdollisuuden käsitellä ajankohtaisia poliittisia ongelmia, kuten esimerkiksi terveydenhuollon tilaa tai yleissivistyksen tasoa Suomessa. Ero Annan julkaisemiin naispoliitikkojen haastatteluihin on selvä. Niiden joukossa vuosina 1975–2005 ei ole sellaisia kirjoituksia, joissa naispoliitikolla olisi itsestäänselvästi asiantuntemusta tai arvovaltaa käsitellä koko kansakuntaa askarruttavia yhteiskunnallisia kysymyksiä. Henkilökohtainen on poliittista Annan julkaisemat poliittikkojen henkilökuvat osoittavat, millä tavoin henkilökohtaisiksi mielletyt asiat ovat muuttuneet poliittisiksi. Kärjistäen voi sanoa, että 1970-luvun puolivälissä Suomessa oli vallalla mielikuva, jossa vastakkain asettuivat miesten politiikka ja naisten yksityiselämä. Kolmessakymmenessä vuodessa tilanne on muuttunut. 1980-luvun alussa Anna argumentoi, että naisten kokemus arkielämästä ja lasten kasvattamisesta antoi heille sellaista asiantuntemusta, jota tulisi hyödyntää myös politiikassa. Annan mukaan miesten hallitseva asema politiikassa oli johtanut tilanteeseen, jossa huomattava osa kansasta ei saanut ääntään politiikassa kuuluviin. 2000-luvulle tultaessa on mahdollista nähdä, että politiikkaan on muodostunut naisille sopivana nähty toiminnan sektori, johon kuuluvat esimerkiksi sosiaali- ja terveydenhuolto, opetus-, ympäristö- ja kulttuuripolitiikka sekä kansainvälinen kehitysyhteistyö. Verrattuna 1970-luvun puolivälin tilanteeseen naiset osallistuvat luontevasti huomattavaan osaan suomalaista politiikkaa. Sukupuolittunut yhteiskunnallinen jakolinja ei kulje enää politiikan ja yksityiselämän välillä, vaan politiikan sisällä. Samalla käsitys politiikasta on muuttunut. Hyvinvointivaltion ja valtion sosiaalisektoriin liittyvien vastuiden laajentuminen on johtanut tilanteeseen, jossa naisille sopiviksi miellettyjen poliittisten osaamisalueiden määrä on kasvanut. On myös puhuttu politiikan intimisaatiosta, jolla tarkoitetaan, että valtioiden poliittisen toiminnan piiri on tullut yhä lähemmäs ihmisten henkilökohtaista elämää. Naisten aikaisempaa laajempi poliittinen osallistuminen ei olisi ollut mahdollista ilman keskustelua aiheista, jotka koetaan hyvin henkilökohtaisiksi: ruumiin ja politiikan suhteesta, yksityiselämän ja julkisen elämän suhteesta tai arkielämän kokemusten suhteesta poliittiseen osallistumiseen. Näin henkilökohtainen ja poliittinen ovat olleet jatkuvassa vuorovaikutuksessa keskenään. Annan henkilökuvat kertovat muutoksesta, jossa yksityiselämän tapahtumat ovat tulleet kiinteäksi osaksi politiikan julkisuutta. Yksityiselämän julkisuus on ollut poliitikoille sekä mahdollisuus että haaste. Yhtäältä yksityiselämän julkisuus on tarjonnut miespoliitikoille oivallisen keinon tuoda esille henkilökohtaisensa elämänsä myönteisiä puolia, esimerkiksi omistautumista perheelle. Naispoliitikoille yksityiselämän tuleminen julkiseksi on tarjonnut keinon haastaa ja kyseenalaistaa niitä arvoja, joiden mukaan nainen ei voi onnistuneesti yhdistää menestystä työ- ja perhe-elämässä. Samalla poliittisen julkisuuden muutos on merkinnyt sitä, että yksityiselämästä on tullut poliitikoille myös rasite. Julkisuudessa ei tehdä selkeää rajaa yksityisen ja julkisen elämän välillä, vaan henkilökohtaisen elämän valinnoista ja tapahtumista on tullut erottamaton osa poliitikkojen julkisuuskuvaa. Annan julkaisemien poliitikkojen henkilökuvien analyysi osoittaa, että poliitikot symboloivat yhteiskunnallisia arvoja ja asenteita. Poliitikot eivät ole vain ihmisiä ansioineen ja puutteineen, vaan heidän saamansa julkisuuden kautta keskustellaan suuremmista yhteiskunnallisista kysymyksistä, kuten naisten oikeudesta osallistua politiikkaa tai sukupuolten välisestä työnjaosta yhteiskunnassa. Annassa ilmestyneet poliitikkojen henkilökuvat ovat olleet osa prosessia, jossa suomalainen sukupuolittunut työnjako on neuvoteltu merkittävältä osaltaan uuteen muotoon. Naiset ovat saaneet vastuulleen olennaisen osan suomalaista politiikkaa samalla kun politiikan sisältö on myös muuttunut. Julkisuudessa näkyvien poliitikkojen henkilökohtaisen elämän valinnat asettuvat kontekstiinsa osana neuvotteluprosessia, jossa mietitään ja kyseenlaistetaan yhteiskunnallisia arvoja ja asenteita. Tässäkin mielessä henkilökohtaisesta on tullut poliittista.

ZigBee-verkot ja evaluointilaitteen suunnittelu

In this thesis a closer look at ZigBee wireless network protocol was made and a ZigBee evaluation device was designed and built for testing it. ZigBee is a digital wireless network technology published in 2004, which was developed for wireless control and automation systems. It is based on the IEEE 802.15.4-2003 standard, and its aim was to create a reliable wireless networking protocol with secure data transmissions, low power consumption and low manufacturing costs. The low power consumption requirement has also led to a slow data rate and a short range, but in a ZigBee network individual network devices can route messages to each other, so short range is not a problem. In automation and control systems a fast data rate is not usually an important requirement either. ZigBee network can form automatically and one ZigBee network can theoretically include thousands of devices, all of which can communicate with each other. ZigBee network is also self-healing, so an individual device dropping out of the network, like breaking down, does not affect functionality of the network. Evaluation device was designed and implemented in four different versions, which were tested with six different antenna designs. All antennas were tested at a range of 100 meters in an open terrain using two different frequencies and transmission powers. Also a range test was performed for selected antennas using transmission power of 4,5 dBm, which was maximum power of the ZigBee chip used in the evaluation device. Range test resulted in a measured range of several hundred meters, which can be considered as a good result for a short-range technology.

Methods for construction and analysis of computational models in systems biology : applications to the modelling of the heat shock response and the self-assembly of intermediate filaments

Systems biology is a new, emerging and rapidly developing, multidisciplinary research field that aims to study biochemical and biological systems from a holistic perspective, with the goal of providing a comprehensive, system- level understanding of cellular behaviour. In this way, it addresses one of the greatest challenges faced by contemporary biology, which is to compre- hend the function of complex biological systems. Systems biology combines various methods that originate from scientific disciplines such as molecu- lar biology, chemistry, engineering sciences, mathematics, computer science and systems theory. Systems biology, unlike “traditional” biology, focuses on high-level concepts such as: network, component, robustness, efficiency, control, regulation, hierarchical design, synchronization, concurrency, and many others. The very terminology of systems biology is “foreign” to “tra- ditional” biology, marks its drastic shift in the research paradigm and it indicates close linkage of systems biology to computer science. One of the basic tools utilized in systems biology is the mathematical modelling of life processes tightly linked to experimental practice. The stud- ies contained in this thesis revolve around a number of challenges commonly encountered in the computational modelling in systems biology. The re- search comprises of the development and application of a broad range of methods originating in the fields of computer science and mathematics for construction and analysis of computational models in systems biology. In particular, the performed research is setup in the context of two biolog- ical phenomena chosen as modelling case studies: 1) the eukaryotic heat shock response and 2) the in vitro self-assembly of intermediate filaments, one of the main constituents of the cytoskeleton. The range of presented approaches spans from heuristic, through numerical and statistical to ana- lytical methods applied in the effort to formally describe and analyse the two biological processes. We notice however, that although applied to cer- tain case studies, the presented methods are not limited to them and can be utilized in the analysis of other biological mechanisms as well as com- plex systems in general. The full range of developed and applied modelling techniques as well as model analysis methodologies constitutes a rich mod- elling framework. Moreover, the presentation of the developed methods, their application to the two case studies and the discussions concerning their potentials and limitations point to the difficulties and challenges one encounters in computational modelling of biological systems. The problems of model identifiability, model comparison, model refinement, model inte- gration and extension, choice of the proper modelling framework and level of abstraction, or the choice of the proper scope of the model run through this thesis.

Configuring Health Care Services - Service Control Improvement

The costs of health care are increasing, and at the same time, population is aging. This leads health care organizations to focus more on home based care services. This thesis focuses on the home care organization of the South Karelian District of Social and Health Services (Eksote), which was established in 2010; how its operation is organized and managed, and which problem types are faced in the daily operation of home care. This thesis examines home care services through an extensive interview study, process mapping and statistical data analysis. To be able to understand the nature of services and special environment theory models, such as service management and performance measurement, service processes and service design are introduced. This study is conducted from an external researcher‟s point of view and should be used as a discussion opener. The outcome of this thesis is an upper level development path for Eksote home care. The organization should evaluate and build a service offering, then productize home care services and modularize the products and identify similarities. Service processes should be mapped to generate efficiency for repeating tasks. Units should be reasonably sized and geographically located to facilitate management and operation. All this can be done by recognizing the different types of service products: runners repeaters and strangers. Furthermore, the organization should not hide behind medical issues and should understand the legislative, medical and operational frameworks in health care.

Oxalic acid and calcium oxalate in production of wood-containing paper : formation, analysis, and control

Papperstillverkningen störs ofta av oönskade föreningar som kan bilda avsättningar på processytor, vilket i sin tur kan ge upphov till störningar i pappersproduktionen samt försämring av papperskvaliteten. Förutom avsättningar av vedharts är stenliknande avlagringar av svårlösliga salter vanliga. I vårt dagliga liv är kalkavlagringar i kaffe- och vattenkokare exempel på liknande problem. I massa- och pappersindustrin är en av de mest problematiska föreningarna kalciumoxalat; detta salt är nästan olösligt i vatten och avlagringarna är mycket svåra att avlägsna. Kalciumoxalat är också känt som en av orsakerna till njurstenar hos människor. Veden och speciellt barken innehåller alltid en viss mängd oxalat men en större källa är oxalsyra som bildas när massan bleks med oxiderande kemikalier, t.ex. väteperoxid. Kalciumoxalat bildas när oxalsyran reagerar med kalcium som kommer in i processen med råvattnet, veden eller olika tillsatsmedel. I denna avhandling undersöktes faktorer som påverkar bildningen av oxalsyra och utfällningen av kalciumoxalat, med hjälp av bleknings- och utfällningsexperiment. Forskningens fokus låg speciellt på olika sätt att förebygga uppkomsten av avlagringar vid tillverkning av trähaltigt papper. Resultaten i denna avhandling visar att bildningen av oxalsyra samt utfällning av kalciumoxalat kan påverkas genom processtekniska och våtändskemiska metoder. Noggrann avbarkning av veden, kontrollerade förhållanden under den alkaliska peroxidblekningen, noggrann hantering och kontroll av andra lösta och kolloidala substanser, samt utnyttjande av skräddarsydd kemi för kontroll av avlagringar är nyckelfaktorer. Resultaten kan utnyttjas då man planerar blekningssekvenser för olika massor samt för att lösa problem orsakade av kalciumoxalat. Forskningsmetoderna som användes i utfällningsstudierna samt för utvärdering av tillsatsmedel kan också utnyttjas inom andra områden, t.ex. bryggeri- och sockerindustrin, där kalciumoxalatproblem är vanligt förekommande. -------------------------------------------- Paperinvalmistusta häiritsevät usein erilaiset epäpuhtaudet, jotka kiinnittyvät prosessipinnoille ja haittaavat tuotantoa sekä paperin laatua. Puun pihkan lisäksi eräs yleinen ongelma on niukkaliukoisten suolojen aiheuttamat kivettymät. Kalkkisaostuma kahvinkeittimessä on esimerkki vastaavasta ongelmasta arkielämässä. Massa- ja paperiteollisuudessa yksi hankalimmista kivettymien muodostajista on kalsiumoksalaatti, koska se on lähes liukenematonta ja sen aiheuttamat saostumat ovat erittäin vaikeasti poistettavia. Kalsiumoksalaatti on yleisesti tunnettu myös munuaiskivien aiheuttajana ihmisillä. Puu ja varsinkin sen kuori sisältää aina jonkin verran oksalaattia, mutta suurempi lähde on kuitenkin oksaalihappo jota muodostuu valkaistaessa massaa hapettavilla kemikaaleilla, kuten vetyperoksidilla. Kalsiumoksalaattia syntyy kun veden, puun ja lisäaineiden mukana prosessiin tuleva kalsium reagoi oksalaatin kanssa. Tässä väitöskirjatyössä tutkittiin oksaalihapon muodostumiseen ja kalsiumoksalaatin saostumiseen vaikuttavia tekijöitä valkaisu- ja saostumiskokeiden avulla. Tutkimuksen painopiste oli saostumien ehkäisemisessä puupitoisten painopaperien valmistuksessa. Työssä saadut tulokset osoittavat että oksaalihapon muodostumiseen ja kalsiumoksalaatin saostumiseen voidaan vaikuttaa sekä prosessiteknisten että märänpään kemian keinojen avulla. Tehokas puun kuorinta, optimoidut olosuhteet peroksidivalkaisussa, muiden liuenneiden ja kolloidisten aineiden hallinta sekä räätälöidyn kemian hyödyntäminen kalsiumoksalaattisaostumien torjunnassa ovat keskeisissä rooleissa ongelmien välttämiseksi. Väitöskirjatyön tuloksia voidaan hyödyntää massan valkaisulinjoja suunniteltaessa sekä kalsiumoksalaatin aiheuttamien ongelmien ratkaisemisessa. Tutkimusmenetelmiä, joita käytettiin saostumiskokeissa ja eri lisäaineiden vaikutusten arvioinnissa, voidaan hyödyntää massa- ja paperiteollisuuden lisäksi myös muilla alueilla, kuten sokeri- ja panimoteollisuudessa, joissa ongelma on myös yleinen.

Power semiconductor nonlinearities in active du/dt output filtering

This doctoral thesis introduces an improved control principle for active du/dt output filtering in variable-speed AC drives, together with performance comparisons with previous filtering methods. The effects of power semiconductor nonlinearities on the output filtering performance are investigated. The nonlinearities include the timing deviation and the voltage pulse waveform distortion in the variable-speed AC drive output bridge. Active du/dt output filtering (ADUDT) is a method to mitigate motor overvoltages in variable-speed AC drives with long motor cables. It is a quite recent addition to the du/dt reduction methods available. This thesis improves on the existing control method for the filter, and concentrates on the lowvoltage (below 1 kV AC) two-level voltage-source inverter implementation of the method. The ADUDT uses narrow voltage pulses having a duration in the order of a microsecond from an IGBT (insulated gate bipolar transistor) inverter to control the output voltage of a tuned LC filter circuit. The filter output voltage has thus increased slope transition times at the rising and falling edges, with an opportunity of no overshoot. The effect of the longer slope transition times is a reduction in the du/dt of the voltage fed to the motor cable. Lower du/dt values result in a reduction in the overvoltage effects on the motor terminals. Compared with traditional output filtering methods to accomplish this task, the active du/dt filtering provides lower inductance values and a smaller physical size of the filter itself. The filter circuit weight can also be reduced. However, the power semiconductor nonlinearities skew the filter control pulse pattern, resulting in control deviation. This deviation introduces unwanted overshoot and resonance in the filter. The controlmethod proposed in this thesis is able to directly compensate for the dead time-induced zero-current clamping (ZCC) effect in the pulse pattern. It gives more flexibility to the pattern structure, which could help in the timing deviation compensation design. Previous studies have shown that when a motor load current flows in the filter circuit and the inverter, the phase leg blanking times distort the voltage pulse sequence fed to the filter input. These blanking times are caused by excessively large dead time values between the IGBT control pulses. Moreover, the various switching timing distortions, present in realworld electronics when operating with a microsecond timescale, bring additional skew to the control. Left uncompensated, this results in distortion of the filter input voltage and a filter self-induced overvoltage in the form of an overshoot. This overshoot adds to the voltage appearing at the motor terminals, thus increasing the transient voltage amplitude at the motor. This doctoral thesis investigates the magnitude of such timing deviation effects. If the motor load current is left uncompensated in the control, the filter output voltage can overshoot up to double the input voltage amplitude. IGBT nonlinearities were observed to cause a smaller overshoot, in the order of 30%. This thesis introduces an improved ADUDT control method that is able to compensate for phase leg blanking times, giving flexibility to the pulse pattern structure and dead times. The control method is still sensitive to timing deviations, and their effect is investigated. A simple approach of using a fixed delay compensation value was tried in the test setup measurements. The ADUDT method with the new control algorithm was found to work in an actual motor drive application. Judging by the simulation results, with the delay compensation, the method should ultimately enable an output voltage performance and a du/dt reduction that are free from residual overshoot effects. The proposed control algorithm is not strictly required for successful ADUDT operation: It is possible to precalculate the pulse patterns by iteration and then for instance store them into a look-up table inside the control electronics. Rather, the newly developed control method is a mathematical tool for solving the ADUDT control pulses. It does not contain the timing deviation compensation (from the logic-level command to the phase leg output voltage), and as such is not able to remove the timing deviation effects that cause error and overshoot in the filter. When the timing deviation compensation has to be tuned-in in the control pattern, the precalculated iteration method could prove simpler and equally good (or even better) compared with the mathematical solution with a separate timing compensation module. One of the key findings in this thesis is the conclusion that the correctness of the pulse pattern structure, in the sense of ZCC and predicted pulse timings, cannot be separated from the timing deviations. The usefulness of the correctly calculated pattern is reduced by the voltage edge timing errors. The doctoral thesis provides an introductory background chapter on variable-speed AC drives and the problem of motor overvoltages and takes a look at traditional solutions for overvoltage mitigation. Previous results related to the active du/dt filtering are discussed. The basic operation principle and design of the filter have been studied previously. The effect of load current in the filter and the basic idea of compensation have been presented in the past. However, there was no direct way of including the dead time in the control (except for solving the pulse pattern manually by iteration), and the magnitude of nonlinearity effects had not been investigated. The enhanced control principle with the dead time handling capability and a case study of the test setup timing deviations are the main contributions of this doctoral thesis. The simulation and experimental setup results show that the proposed control method can be used in an actual drive. Loss measurements and a comparison of active du/dt output filtering with traditional output filtering methods are also presented in the work. Two different ADUDT filter designs are included, with ferrite core and air core inductors. Other filters included in the tests were a passive du/dtfilter and a passive sine filter. The loss measurements incorporated a silicon carbide diode-equipped IGBT module, and the results show lower losses with these new device technologies. The new control principle was measured in a 43 A load current motor drive system and was able to bring the filter output peak voltage from 980 V (the previous control principle) down to 680 V in a 540 V average DC link voltage variable-speed drive. A 200 m motor cable was used, and the filter losses for the active du/dt methods were 111W–126 W versus 184 W for the passive du/dt. In terms of inverter and filter losses, the active du/dt filtering method had a 1.82-fold increase in losses compared with an all-passive traditional du/dt output filter. The filter mass with the active du/dt method was 17% (2.4 kg, air-core inductors) compared with 14 kg of the passive du/dt method filter. Silicon carbide freewheeling diodes were found to reduce the inverter losses in the active du/dt filtering by 18% compared with the same IGBT module with silicon diodes. For a 200 m cable length, the average peak voltage at the motor terminals was 1050 V with no filter, 960 V for the all-passive du/dt filter, and 700 V for the active du/dt filtering applying the new control principle.

Flexible multibody dynamics and intelligent control of a hydraulically driven hybrid redundant robot machine

The assembly and maintenance of the International Thermonuclear Experimental Reactor (ITER) vacuum vessel (VV) is highly challenging since the tasks performed by the robot involve welding, material handling, and machine cutting from inside the VV. The VV is made of stainless steel, which has poor machinability and tends to work harden very rapidly, and all the machining operations need to be carried out from inside of the ITER VV. A general industrial robot cannot be used due to its poor stiffness in the heavy duty machining process, and this will cause many problems, such as poor surface quality, tool damage, low accuracy. Therefore, one of the most suitable options should be a light weight mobile robot which is able to move around inside of the VV and perform different machining tasks by replacing different cutting tools. Reducing the mass of the robot manipulators offers many advantages: reduced material costs, reduced power consumption, the possibility of using smaller actuators, and a higher payload-to-robot weight ratio. Offsetting these advantages, the lighter weight robot is more flexible, which makes it more difficult to control. To achieve good machining surface quality, the tracking of the end effector must be accurate, and an accurate model for a more flexible robot must be constructed. This thesis studies the dynamics and control of a 10 degree-of-freedom (DOF) redundant hybrid robot (4-DOF serial mechanism and 6-DOF 6-UPS hexapod parallel mechanisms) hydraulically driven with flexible rods under the influence of machining forces. Firstly, the flexibility of the bodies is described using the floating frame of reference method (FFRF). A finite element model (FEM) provided the Craig-Bampton (CB) modes needed for the FFRF. A dynamic model of the system of six closed loop mechanisms was assembled using the constrained Lagrange equations and the Lagrange multiplier method. Subsequently, the reaction forces between the parallel and serial parts were used to study the dynamics of the serial robot. A PID control based on position predictions was implemented independently to control the hydraulic cylinders of the robot. Secondly, in machining, to achieve greater end effector trajectory tracking accuracy for surface quality, a robust control of the actuators for the flexible link has to be deduced. This thesis investigates the intelligent control of a hydraulically driven parallel robot part based on the dynamic model and two schemes of intelligent control for a hydraulically driven parallel mechanism based on the dynamic model: (1) a fuzzy-PID self-tuning controller composed of the conventional PID control and with fuzzy logic, and (2) adaptive neuro-fuzzy inference system-PID (ANFIS-PID) self-tuning of the gains of the PID controller, which are implemented independently to control each hydraulic cylinder of the parallel mechanism based on rod length predictions. The serial component of the hybrid robot can be analyzed using the equilibrium of reaction forces at the universal joint connections of the hexa-element. To achieve precise positional control of the end effector for maximum precision machining, the hydraulic cylinder should be controlled to hold the hexa-element. Thirdly, a finite element approach of multibody systems using the Special Euclidean group SE(3) framework is presented for a parallel mechanism with flexible piston rods under the influence of machining forces. The flexibility of the bodies is described using the nonlinear interpolation method with an exponential map. The equations of motion take the form of a differential algebraic equation on a Lie group, which is solved using a Lie group time integration scheme. The method relies on the local description of motions, so that it provides a singularity-free formulation, and no parameterization of the nodal variables needs to be introduced. The flexible slider constraint is formulated using a Lie group and used for modeling a flexible rod sliding inside a cylinder. The dynamic model of the system of six closed loop mechanisms was assembled using Hamilton’s principle and the Lagrange multiplier method. A linearized hydraulic control system based on rod length predictions was implemented independently to control the hydraulic cylinders. Consequently, the results of the simulations demonstrating the behavior of the robot machine are presented for each case study. In conclusion, this thesis studies the dynamic analysis of a special hybrid (serialparallel) robot for the above-mentioned special task involving the ITER and investigates different control algorithms that can significantly improve machining performance. These analyses and results provide valuable insight into the design and control of the parallel robot with flexible rods.

Cost-efficient virtual machine management : provisioning, admission control, and consolidation

One of the main challenges in Software Engineering is to cope with the transition from an industry based on software as a product to software as a service. The field of Software Engineering should provide the necessary methods and tools to develop and deploy new cost-efficient and scalable digital services. In this thesis, we focus on deployment platforms to ensure cost-efficient scalability of multi-tier web applications and on-demand video transcoding service for different types of load conditions. Infrastructure as a Service (IaaS) clouds provide Virtual Machines (VMs) under the pay-per-use business model. Dynamically provisioning VMs on demand allows service providers to cope with fluctuations on the number of service users. However, VM provisioning must be done carefully, because over-provisioning results in an increased operational cost, while underprovisioning leads to a subpar service. Therefore, our main focus in this thesis is on cost-efficient VM provisioning for multi-tier web applications and on-demand video transcoding. Moreover, to prevent provisioned VMs from becoming overloaded, we augment VM provisioning with an admission control mechanism. Similarly, to ensure efficient use of provisioned VMs, web applications on the under-utilized VMs are consolidated periodically. Thus, the main problem that we address is cost-efficient VM provisioning augmented with server consolidation and admission control on the provisioned VMs. We seek solutions for two types of applications: multi-tier web applications that follow the request-response paradigm and on-demand video transcoding that is based on video streams with soft realtime constraints. Our first contribution is a cost-efficient VM provisioning approach for multi-tier web applications. The proposed approach comprises two subapproaches: a reactive VM provisioning approach called ARVUE and a hybrid reactive-proactive VM provisioning approach called Cost-efficient Resource Allocation for Multiple web applications with Proactive scaling. Our second contribution is a prediction-based VM provisioning approach for on-demand video transcoding in the cloud. Moreover, to prevent virtualized servers from becoming overloaded, the proposed VM provisioning approaches are augmented with admission control approaches. Therefore, our third contribution is a session-based admission control approach for multi-tier web applications called adaptive Admission Control for Virtualized Application Servers. Similarly, the fourth contribution in this thesis is a stream-based admission control and scheduling approach for on-demand video transcoding called Stream-Based Admission Control and Scheduling. Our fifth contribution is a computation and storage trade-o strategy for cost-efficient video transcoding in cloud computing. Finally, the sixth and the last contribution is a web application consolidation approach, which uses Ant Colony System to minimize the under-utilization of the virtualized application servers.

Designing new learning experiences? : exploring corporate E-learners’ self-regulated learning

The context of this study is corporate e-learning, with an explicit focus on how digital learning design can facilitate self-regulated learning (SRL). The field of e-learning is growing rapidly. An increasing number of corporations use digital technology and elearning for training their work force and customers. E-learning may offer economic benefits, as well as opportunities for interaction and communication that traditional teaching cannot provide. However, the evolving variety of digital learning contexts makes new demands on learners, requiring them to develop strategies to adapt and cope with novel learning tools. This study derives from the need to learn more about learning experiences in digital contexts in order to be able to design these properly for learning. The research question targets how the design of an e-learning course influences participants’ self-regulated learning actions and intentions. SRL involves learners’ ability to exercise agency in their learning. Micro-level SRL processes were targeted by exploring behaviour, cognition, and affect/motivation in relation to the design of the digital context. Two iterations of an e-learning course were tested on two groups of participants (N=17). However, the exploration of SRL extends beyond the educational design research perspective of comparing the effects of the changes to the course designs. The study was conducted in a laboratory with each participant individually. Multiple types of data were collected. However, the results presented in this thesis are based on screen observations (including eye tracking) and video-stimulated recall interviews. These data were integrated in order to achieve a broad perspective on SRL. The most essential change evident in the second course iteration was the addition of feedback during practice and the final test. Without feedback on actions there was an observable difference between those who were instruction-directed and those who were self-directed in manipulating the context and, thus, persisted whenever faced with problems. In the second course iteration, including the feedback, this kind of difference was not found. Feedback provided the tipping point for participants to regulate their learning by identifying their knowledge gaps and to explore the learning context in a targeted manner. Furthermore, the course content was consistently seen from a pragmatic perspective, which influenced the participants’ choice of actions, showing that real life relevance is an important need of corporate learners. This also relates to assessment and the consideration of its purpose in relation to participants’ work situation. The rigidity of the multiple choice questions, focusing on the memorisation of details, influenced the participants to adapt to an approach for surface learning. It also caused frustration in cases where the participants’ epistemic beliefs were incompatible with this kind of assessment style. Triggers of positive and negative emotions could be categorized into four levels: personal factors, instructional design of content, interface design of context, and technical solution. In summary, the key design choices for creating a positive learning experience involve feedback, flexibility, functionality, fun, and freedom. The design of the context impacts regulation of behaviour, cognition, as well as affect and motivation. The learners’ awareness of these areas of regulation in relation to learning in a specific context is their ability for design-based epistemic metareflection. I describe this metareflection as knowing how to manipulate the context behaviourally for maximum learning, being metacognitively aware of one’s learning process, and being aware of how emotions can be regulated to maintain volitional control of the learning situation. Attention needs to be paid to how the design of a digital learning context supports learners’ metareflective development as digital learners. Every digital context has its own affordances and constraints, which influence the possibilities for micro-level SRL processes. Empowering learners in developing their ability for design-based epistemic metareflection is, therefore, essential for building their digital literacy in relation to these affordances and constraints. It was evident that the implementation of e-learning in the workplace is not unproblematic and needs new ways of thinking about learning and how we create learning spaces. Digital contexts bring a new culture of learning that demands attitude change in how we value knowledge, measure it, define who owns it, and who creates it. Based on the results, I argue that digital solutions for corporate learning ought to be built as an integrated system that facilitates socio-cultural connectivism within the corporation. The focus needs to shift from designing static e-learning material to managing networks of social meaning negotiation as part of a holistic corporate learning ecology.

Business intelligence – enabling self-service: A case study in a global manufacturing company

Business intelligence (BI) is an information process that includes the activities and applications used to transform business data into valuable business information. Today’s enterprises are collecting detailed data which has increased the available business data drastically. In order to meet changing customer needs and gain competitive advantage businesses try to leverage this information. However, IT departments are struggling to meet the increased amount of reporting needs. Therefore, recent shift in the BI market has been towards empowering business users with self-service BI capabilities. The purpose of this study was to understand how self-service BI could help businesses to meet increased reporting demands. The research problem was approached with an empirical single case study. Qualitative data was gathered with a semi-structured, theme-based interview. The study found out that case company’s BI system was mostly used for group performance reporting. Ad-hoc and business user-driven information needs were mostly fulfilled with self-made tools and manual work. It was felt that necessary business information was not easily available. The concept of self-service BI was perceived to be helpful to meet such reporting needs. However, it was found out that the available data is often too complex for an average user to fully understand. The respondents felt that in order to self-service BI to work, the data has to be simplified and described in a way that it can be understood by the average business user. The results of the study suggest that BI programs struggle in meeting all the information needs of today’s businesses. The concept of self-service BI tries to resolve this problem by allowing users easy self-service access to necessary business information. However, business data is often complex and hard to understand. Self-serviced BI has to overcome this challenge before it can reach its potential benefits.

Accelerating food safety and quality control: The use of antibody engineering techniques in the detec-tion of low-molecular weight food contaminants

The increased awareness and evolved consumer habits have set more demanding standards for the quality and safety control of food products. The production of foodstuffs which fulfill these standards can be hampered by different low-molecular weight contaminants. Such compounds can consist of, for example residues of antibiotics in animal use or mycotoxins. The extremely small size of the compounds has hindered the development of analytical methods suitable for routine use, and the methods currently in use require expensive instrumentation and qualified personnel to operate them. There is a need for new, cost-efficient and simple assay concepts which can be used for field testing and are capable of processing large sample quantities rapidly. Immunoassays have been considered as the golden standard for such rapid on-site screening methods. The introduction of directed antibody engineering and in vitro display technologies has facilitated the development of novel antibody based methods for the detection of low-molecular weight food contaminants. The primary aim of this study was to generate and engineer antibodies against low-molecular weight compounds found in various foodstuffs. The three antigen groups selected as targets of antibody development cause food safety and quality defects in wide range of products: 1) fluoroquinolones: a family of synthetic broad-spectrum antibacterial drugs used to treat wide range of human and animal infections, 2) deoxynivalenol: type B trichothecene mycotoxin, a widely recognized problem for crops and animal feeds globally, and 3) skatole, or 3-methyindole is one of the two compounds responsible for boar taint, found in the meat of monogastric animals. This study describes the generation and engineering of antibodies with versatile binding properties against low-molecular weight food contaminants, and the consecutive development of immunoassays for the detection of the respective compounds.

Business intelligence – enabling self-service: A case study in a global manufacturing company

Business intelligence (BI) is an information process that includes the activities and applications used to transform business data into valuable business information. Today’s enterprises are collecting detailed data which has increased the available business data drastically. In order to meet changing customer needs and gain competitive advantage businesses try to leverage this information. However, IT departments are struggling to meet the increased amount of reporting needs. Therefore, recent shift in the BI market has been towards empowering business users with self-service BI capabilities. The purpose of this study was to understand how self-service BI could help businesses to meet increased reporting demands. The research problem was approached with an empirical single case study. Qualitative data was gathered with a semi-structured, theme-based interview. The study found out that case company’s BI system was mostly used for group performance reporting. Ad-hoc and business user-driven information needs were mostly fulfilled with self-made tools and manual work. It was felt that necessary business information was not easily available. The concept of self-service BI was perceived to be helpful to meet such reporting needs. However, it was found out that the available data is often too complex for an average user to fully understand. The respondents felt that in order to self-service BI to work, the data has to be simplified and described in a way that it can be understood by the average business user. The results of the study suggest that BI programs struggle in meeting all the information needs of today’s businesses. The concept of self-service BI tries to resolve this problem by allowing users easy self-service access to necessary business information. However, business data is often complex and hard to understand. Self-serviced BI has to overcome this challenge before it can reach its potential benefits.

Perfluorattuja yhdisteitä sisältävien jätevesien puhdistus- ja analyysimenetelmät

Perfluoratut alkyyliyhdisteet eli PFAS-yhdisteet ovat synteettisiä orgaanisia yhdisteitä, joissa on fluorattu hiiliketju. Hiilen ja fluorin väliset vahvat sidokset ovat muodostuneet ongelmaksi jätevedenpuhdistamoilla, sillä yhdisteet eivät hajoa puhdistamoilla käytössä olevilla vedenpuhdistusmenetelmillä. Yhdisteitä kertyy luontoon jätevesien mukana. Kandidaatintyössä on vertailtu yhdisteitä sisältävien vesien käsittelymenetelmiä parhaiten soveltuvan menetelmän löytämiseksi. Menetelmien kustannuksia tai soveltuvuutta vedenpuhdistamomittakaavan prosessiksi ei ole arvioitu. Lisäksi työssä on koottu yhdisteitä sisältävien jätevesien analysointiin sopivia analyysimenetelmiä. Soveltuvat puhdistus- ja analyysimenetelmät on esitelty uusien tieteellisten artikkelien pohjalta. Mahdollisia erotusmenetelmiä ovat membraanierotus ja sorptio. Membraaneista soveltuvimpia ovat nanosuodatus- ja käänteisosmoosimembraanit, joilla erottuvat jopa 0,0001 μm:n kokoiset partikkelit. PFAS-yhdisteet voidaan erottaa sorptiolla muun muassa aktiivihiileen. Yhdisteiden rakenne hajoaa nykyaikaisilla hapetusmenetelmillä ja polttamalla lietteen mukana. Hapettaminen permanganaatin avulla ei tuottanut hyvää tulosta, mutta fotokemiallisella hapetuksella ja alhaisen lämpötilan plasmatekniikalla (NTP) yhdisteiden rakenne hajosi lähes kokonaan. Fotokemiallinen hapetus onnistui erityisesti perfluorokarboksyylihapoilla, joiden rakenne hajosi jopa kolmessa tunnissa. Yleisimmin käytetty analyysimenetelmä on nestekromatografin ja massaspektrometrin yhdistelmä (LC-MS/MS) ja matriisivaikutus minimoidaan tyypillisesti kiinteäfaasiuutolla (SPE). Työssä esitellyistä käsittelymenetelmistä parhaiten soveltuva on NTP-menetelmä, koska sillä saatiin tutkimusten mukaan hajotettua yhdisteiden rakenne muita menetelmiä lyhyemmässä ajassa ja se soveltuu parhaiten kaikille PFAS-yhdisteille. NTP-menetelmässä ei tarvita katalyyttiä tai lisäkemikaaleja. Voimakkaana hapettimena toimivat epästabiilit hydroksyyliradikaalit, jotka syntyvät koronapurkauksen kautta. Koronapurkauksessa muodostuu myös otsonia ja lisäksi vapaa happi voi tehostaa hapettumista. Menetelmässä muodostuvien hajoamistuotteiden hallinta vaatii lisätutkimusta. Mahdollinen hallintakeino voisi olla esimerkiksi hapettumisessa vapautuvien fluoridi-ionien saostaminen. Muodostuvien hajoamistuotteiden toksisuutta voitaisiin tarkkailla biosensorilla.