Energy Efficient Boom Actuation Using a Digital Hydraulic Power Management System

Hydraulic systems are widely used in mobile machines such as construction machinery and forest machinery. Modern hydraulics relies on Load Sensing (LS) systems. The solution is based on adjusting the flow and pressure according to the requirements of actuators. And further, the actuators are controlled by proportional valves by throttling the flow. A problem of LS systems is poor energy efficiency, especially when the load is overrunning. Moreover, in multi-actuator systems, the supply pressure is set according to the highest demand, whereas the actuator flows are controlled independently; thus, the pressure matching losses can become extremely high in a case where actuators with high flow demand operate at pressure levels significantly below that of the maximum pressure. A solution to tackle these problems could be a Digital Hydraulic Power Management System (DHPMS). Based on digital pump/motor technology, the DHPMS has the potential for high energy efficiency. Moreover, multiple independent outlets enable new innovative system layouts.In this thesis a novel approach for hydraulic systems is considered. A piston-type DHPMS with displacement controlled actuators could theoretically compose a lossless hydraulic drive. The research investigates the possibility of putting the direct control approach into practice. In addition, a control method for a Digital Hydraulic Hybrid (DHH) with displacement controlled actuators is proposed. The hybrid system utilizes a hydraulic accumulator as an energy source/sink; the prime mover can be assisted during high power demand and the recoverable energy can be temporarily stored for reuse. Simulations and experimental test are used to validate the system.The results imply that the DHH with displacement controlled actuators is a feasible approach; a model based controller provides good position tracking without position feedback, and the power of an electric motor can be stabilized by utilizing the accumulator. Moreover, the full capacity of the energy storing device can be utilized because the DHPMS can act as a hydraulic transformer. The measurements show that for the studied trajectory, the direct cylinder control decreases the system losses by about 50% in comparison with an Electrical Load Sensing (ELS) system with a proportional controlled cylinder. Hydraulic losses in the supply lines are instead reduced by about 89%. Thus, the energy saving potential of the new approach is substantial, but the structure of the DHPMS has to be well considered; the efficiency of the system mainly depends on the efficiency of the multioutlet digital pump/motor unit. In addition, pumping pistons with small geometrical displacement are needed to accomplish sophisticated control performance

Quasi-pseudolikelihood in Markov network structure learning

Probabilistic graphical models are a versatile tool for doing statistical inference with complex models. The main impediment for their use, especially with more elaborate models, is the heavy computational cost incurred. The development of approximations that enable the use of graphical models in various tasks while requiring less computational resources is therefore an important area of research. In this thesis, we test one such recently proposed family of approximations, called quasi-pseudolikelihood (QPL). Graphical models come in two main variants: directed models and undirected models, of which the latter are also called Markov networks or Markov random fields. Here we focus solely on the undirected case with continuous valued variables. The specific inference task the QPL approximations target is model structure learning, i.e. learning the model dependence structure from data. In the theoretical part of the thesis, we define the basic concepts that underpin the use of graphical models and derive the general QPL approximation. As a novel contribution, we show that one member of the QPL approximation family is not consistent in the general case: asymptotically, for this QPL version, there exists a case where the learned dependence structure does not converge to the true model structure. In the empirical part of the thesis, we test two members of the QPL family on simulated datasets. We generate datasets from Ising models and Sherrington-Kirkpatrick models and try to learn them using QPL approximations. As a reference method, we use the well-established Graphical lasso (Glasso). Based on our results, the tested QPL approximations work well with relatively sparse dependence structures, while the more densely connected models, especially with weaker interaction strengths, present challenges that call for further research

Performanssiteorian tulkinta suomalaisessa folkloristiikassa

Tarkastelen pro-gradu työssäni performanssiteorian tulkintaa osana suomalaisen folkloristiikan oppihistoriaa. Tavoitteena on selvittää, ketkä ko. teoriaa kulloinkin kommentoivat, miten teoriaa tulkitaan ja lopulta miten tiettyjä tulkintatapoja voidaan selittää oppihistorian avulla. Työni pääasiallinen aineisto koostuu 1960-2000 julkaistuista teksteistä, joissa käsitellään performanssiteoriaa. Tätä yleisemmän oppihistoriallisen kronologian luomiseksi aineistooni kuuluvat myös em. ajanjaksona alalta Suomessa valmistuneet väitöskirjat sekä kolmen folkloristien säännöllisesti julkaisukanavanaan käyttämän julkaisun vuosikerrat samalta ajalta. Analyysimetodina käytän tekstien lähilukua. Analyysini perusteella performanssiteorian tulkinnassa on havaittavissa kaksi suuntausta: 1980-luvun vaihteesta alkaen teoriaa kritisoiva ja sen hylkäävä tulkinta sekä 1990-luvun vaihteesta alkaen teoriaa tutkimuksessa soveltava tulkinta. Käsittelemäni ajanjakson lopulla molemmista tulkintatavoista löytyy esimerkkejä. Näistä kahdesta tulkintamallista performanssiteorian hylkäävässä suuntauksessa teoriaa tulkitaan suomalaisessa folkloristiikassa aiemmin vakiintuneiden käsitteiden kautta, jotka eivät ole yhteensopivia performanssiteorian käsitteistön kanssa. Tästä syystä kritiikki ei lähemmin tarkasteltuna ole hyvin perusteltua

Aikapaikkaisia lisiä Fennoskandian kielelliseen esihistoriaan

My academic dissertation "Bidrag till Fennoskandiens språkliga förhistoria i tid och rum" ("Spatiotemporal Contributions to the Linguistic Prehistory of Fennoscandia") is an interdisciplinary study of the linguistic prehistory of Northern Europe chiefly in the Iron Age (ca. 700 BC―AD 1200), but also to some extent in the Bronze Age (ca. 1700―700 BC) and the Early Finnish Middle Ages (ca. AD 1200―1323). The disciplines represented in this study are Germanistics, Nordistics, Finnougristics, history and archaeology. The language-forms studied are Proto-Germanic, Proto-Scandinavian, Proto-Finnic and Proto-Sami. This dissertation uses historical-comparative linguistics and especially loanword study to examine the relative and absolute chronology of the sound changes that have taken place in the proto-forms of the Germanic, Finnic and Samic languages. Phonetic history is the basis of historical linguistics studying the diachronic development of languages. To my knowledge, this study is the first in the history of the disciplines mentioned above to examine the systematic dating of the phonetic development of these proto-languages in relation to each other. In addition to the dating and relating of the phonetic development of the proto-languages, I study Fennoscandian toponyms. The oldest datable and etymologizable place-names throw new light on the ethnic history and history of settlement of Fennoscandia. For instance, I deal with the etymology of the following place-names: Ahvenanmaa/Åland, Eura(joki), Inari(järvi), Kemi(joki), Kvenland, Kymi(joki), Sarsa, Satakunta, Vanaja, Vantaa and Ähtäri. My dissertation shows that Proto-Germanic, Proto-Scandinavian, Proto-Finnic and Proto-Sami all date to different periods of the Iron Age. I argue that the present study along with my earlier published research also proves that a (West-)Uralic language – the pre-form of the Finnic and Samic languages – was spoken in the region of the present-day Finland in the Bronze Age, but not earlier than that. In the centuries before the Common Era, Proto-Sami was spoken in the whole region of what is now called Finland, excluding Lapland. At the beginning of the Common Era, Proto-Sami was spoken in the whole region of Finland, including Southern Finland, from where the Sami idiom first began to recede. An archaic (Northwest-)Indo-European language and a subsequently extinct Paleo-European language were likely spoken in what is now called Finland and Estonia, when the linguistic ancestors of the Finns and the Sami arrived in the eastern and northern Baltic Sea region from the Volga-Kama region probably at the beginning of the Bronze Age. For example, the names Suomi ʻFinlandʼ and Viro ʻEstoniaʼ are likely to have been borrowed from the Indo-European idiom in question. (Proto-)Germanic waves of influence have come from Scandinavia to Finland since the Bronze Age. A considerable part of the Finnic and Samic vocabulary is indeed Germanic loanwords of different ages which form strata in these languages. Besides mere etymological research, these numerous Germanic loanwords make it possible to relate to each other the temporal development of the language-forms that have been in contact with each other. That is what I have done in my extensive dissertation, which attempts to be both a detailed and a holistic treatise.Väitöskirjassani "Bidrag till Fennoskandiens språkliga förhistoria i tid och rum" ("Aikapaikkaisia lisiä Fennoskandian kielelliseen esihistoriaan") tutkin poikkitieteellistä lähestymistapaa noudattaen Pohjois-Euroopan kielellistä esihistoriaa erityisesti rautakaudella (n. 700 eKr.―1200 jKr.), mutta jonkin verran myös pronssikaudella (n. 1700―700 eKr.) ja Suomen varhaiskeskiajalla (n. 1200―1323 jKr.). Tieteenaloista edustettuina ovat germanistiikka, nordistiikka, fennougristiikka, historiatiede ja arkeologia. Keskeisintä väitöskirjassani on germaanisten kielten, (itämeren)suomen ja saamen kielten esimuodoissa tapahtuneiden äänteenmuutosten tapahtumajärjestyksen ja tapahtuma-ajan eli suhteellisen ja absoluuttisen kronologian selvittäminen historiallis-vertailevan kielitieteen ja erityisesti lainasanatutkimuksen avulla. Äännehistoria on kielten ajallista muuttumista tutkivan historiallisen kielitieteen perusta. Mainittujen kantakielten äännekehityksen systemaattinen ajoittaminen suhteessa toisiinsa tehdään väitöskirjassani ensimmäistä kertaa edellä mainittujen tieteenalojen historiassa. Kantakielissä tapahtuneen äännekehityksen ajoituksen ja toisiinsa suhteuttamisen lisäksi tutkin väitöskirjassani Fennoskandian paikannimiä. Vanhimmat ajoitettavissa ja etymologioitavissa eli alkuperältään selvitettävissä olevat paikannimet tuovat uutta tietoa Pohjois-Euroopan asutushistoriasta ja etnisestä historiasta. Käsittelen muun muassa seuraavien paikannimien etymologiaa: Ahvenanmaa/Åland, Eura(joki), Inari(järvi), Kemi(joki), Kokemäki, Kymi(joki), Köyliö, Lappi, Ounasjoki, Sarsa, Satakunta, Vanaja, Vantaa ja Ähtäri. Väitöskirjani osoittaa, että kantasuomi, kantasaame, kaikkien germaanisten kielten esimuoto kantagermaani ja pohjoisgermaanisten eli skandinaavisten kielten esimuoto kantaskandinaavi ajoittuvat kaikki rautakauden eri vaiheisiin. Väitän väitöskirjatutkimukseni sekä aiemman tieteellisen tuotantoni myös osoittavan, että (länsi)uralilaista kieltä – suomen ja saamen kielen esimuotoa – on puhuttu nykyisen Suomen valtion alueella jo pronssikaudelta alkaen, muttei sitä aiemmin. Kantasaamea on ennen ajanlaskun alkua puhuttu koko nykyisen Suomen alueella Lappia lukuun ottamatta. Ajanlaskun alussa kantasaamea puhuttiin koko nykyisen Suomen alueella, Etelä-Suomi mukaan luettuna, mistä saamen kieli on sittemmin ensimmäisenä väistynyt. Nykyisen Suomen alueella ja sen lähialueilla lienee puhuttu hyvin vanhakantaista (luoteis)indoeurooppalaista kieltä ja sittemmin kadonnutta muinaiskieltä, kun suomalaisten ja saamelaisten kielelliset esi-isät saapuivat maahan (Itämeren alueelle) itäkaakosta Volgan-Kaman alueelta luultavasti pronssikauden alussa. Esimerkiksi nimet Suomi ja Viro lienee lainattu kyseisestä indoeurooppalaisesta kielimuodosta. Skandinaviasta on pronssikaudelta alkaen tullut nykyisen Suomen alueelle (kanta)germaanisia vaikutusaaltoja. Itämerensuomen ja saamen sanastosta huomattava osa onkin eri-ikäisiä germaanisia lainasanoja, jotka muodostavat kielessä eriaikaisia kerrostumia. Nämä lukuisat eri-ikäiset germaaniset lainasanat mahdollistavat pelkän etymologisen eli sanahistoriallisen tutkimuksen lisäksi kontaktissa olleiden kielimuotojen kehityksen ajallisen suhteuttamisen toisiinsa, minkä olen tehnyt aiheeltaan ja aineistoltaan laajassa väitöstutkimuksessani

Configuration of skilled tasks for execution in multipurpose and collaborative service robots

Several highly versatile mobile robots have been introduced during the last ten years. Some of these robots are working among people in exhibitions and other public places, such as museums and shopping centers. Unlike industrial robots, which are typically found only in manufacturing environments, service robots can be found in a variety of places, ranging from homes to offices, and from hospitals to restaurants. Developing mobile robots working co-operatively with humans raises not only interaction problems but problems in getting tasks accomplished. In an unstructured and dynamic environment this is not readily achievable because of the high degree of complexity of perception and motion of the robots. Such tasks require high-level perception and locomotion systems, not to mention control systems for all levels of task control. The lowest levels are controlling the motors and sensors of the robots and the highest are sophisticated task planners for complex and useful tasks. Human-friendly communication can be seen as an important factor in getting robots into our homes. In this work a new task configuration concept is proposed for multipurpose service robots. The concept gives guidelines for a software architecture and task managing system. Task configuration process presents a new method which makes it easier to configure a new task for a robot. The idea is the same as when a person tells another how a task should be performed. Novel method for executing tasks with service robots is also presented. Interpretive execution, keeping the focus on only one micro task at a time, makes it possible to modify plans during their execution. Multimodal interaction is important feature to provide collaboration between humans and robots. Multimodal interaction reduces the workload of the user by administering task configuration and execution. A novel solution for using multimodal human-robot interaction (HRI) as a part of the task description is presented. This thesis is a case study reporting the results when developing a task managing (from configuring to execution) platform for multipurpose service robots and studying its performance and use with several test cases. The platform that was developed has been implemented with the WorkPartner multipurpose service robot. The structure and operation of the platform have proved to be useful and several tasks have been carried out successfully

Suomalaisen kansanuskon keskipitkä oppimäärä

Arvosteltu teos: Suomalainen kansanusko: Samaaneista saunatonttuihin / Risto Pulkkinen. Helsinki : Gaudeamus, 2014

ALUSSA OLI APINA, VAISTO JA ELEKIELI, SITTEN TULIVAT PUHE, AATOS JA IHMISMIELI

Näkökohtia puheen alkuperästä (toim. OlliAaltonen, Mona Lehtinen & Reijo Aulanko,2012, 199 sivua, Mediapinta