Mallinnuksen käyttö arvioitaessa ilmastonmuutoksen vaikutusta havu- ja lehtinunnan levinneisyyteen

Seloste artikkelista: Vanhanen, H., Veteli, T. O., Päivinen, S., Kellomäki, S. & Niemelä, P. 2007. Climate change and range shifts in two insect defoliators: gypsy moth and nun moth - a model study. Silva Fennica 41 (4) : 621-638

Calculation of wood volume and stem taper using terrestrial single-image close-range photogrammetry and contemporary software tools

Abstract

Development of aBuyer-Supplier Relationship: Case Study of Radical Shifts in Key Account Relationships

Tämän tutkimuksen tavoitteena oli tutkia ja selvittää monimutkaisia myyjän ja toimittajan välisiä liikesuhteita; miten ne kehittyvät ja millaisia prosesseja ne käyvät läpi, jos avainasiakassuhde on vaikeuksissa. Tavoitteena oli myös löytää syitä miksi ostokäyttäytyminen on muuttunut, onko se maailman- laajuinen ilmiö vai onko kyse vain yksittäisestä tapauksesta paperiteolli-suudessa. Lisäksi tavoitteena oli selvittää mitkä ovat alkusysäyksiä avain-asiakassuhteen murrostilaan. Tutkimuksen lähestymistapa on kvalitatiivinen tapaustutkimus. Tutkimuksen ensisijainen empiirinen aineisto on kerätty haastattelemalla UPM-Kymmenen johtoa, paperin osto-organisaation ostojohtajaa X ja asiakas Y:n entistä osto-johtajaa. Työ ei ole salainen. Tämän takia asiakkaiden nimiä ei voida julkaista, koska UPM-Kymmene vaati, että työ ei saa sisältää mitään informaatiota, josta lukija voi tunnistaa asiakas X:n tai Y:n. Johtopäätöksenä voidaan suosittaa toimittajan tarkkailevan ja ymmärtävän mahdollisia alkusysäyksiä ja varoitussignaaleja ehkäistäkseen tulevaisuuden murrostiloja liikesuhteissaan ja hallita paremmin avainasiakkaitaan.Pääasialliset alkusysäykset ovat vähentynyt avoin kommunikaatio, ostajan radikaalit säästöt, vähentynyt informaation vaihto ja ostajan johdon vaihtuminen, koska se luo epävarmuutta toimittajaan kuten myös ostajaan.

Palkanlaskentajärjestelmän kehittäminen

Työn tavoitteena oli selvittää palkanlaskennan nykytilaa ja sen uudistamisen mahdollisuuksia etenkin SAP HR-ohjelmiston valossa. Ensin selvitettiin palkanlaskentaan ja sovellushankintaan liittyviä vaatimuksia kirjallisuuden avulla. Tämän jälkeen tutustuttiin palkanlaskennan nykytilaan haastattelujen, prosessikuvausten ja sisäisten dokumenttien avulla. SAP HR-ohjelmistoon tutustuttiin siihen liittyneiden työtehtävien, erilaisten koulutusmateriaalien ja esittelyiden avulla. Yrityksessä on jo aiemmin yritetty korvata henkilöstö- ja palkanlaskentajärjestelmiä, mutta projekti keskeytettiin. SAP HR-ohjelmiston henkilöstöhallinto-osuutta ollaan ottamassa käyttöön koko yrityksen laajuudessa. Palkanlaskentajärjestelmä vaatii pikaista uusintaa vanhan teknologian ja suuren henkilöriippuvuuden takia. Nykyiset työajanhallinnan ja palkanlaskennan prosessit yrityksessä ovat tiukasti sidottuja nykyisten järjestelmien kanssa ja uuden järjestelmän käyttöönotto vaatii muutoksia koko ketjuun työvuorojen suunnittelusta palkanlaskentaan ja raportointiin asti. Johtopäätöksenä todetaan SAP HR:n palkanlaskennan soveltuvan yrityksen palkanlaskentaan ja tarjoavan monia uusia mahdollisuuksia. Suurimmat mahdollisuudet liittyvät kokonaisten prosessiketjujen läpinäkyvyyteen ja parempaan ohjailtavuuteen. Tämä kuitenkin vaatii nykyistä tarkempaa sisäisten prosessien selvittämistä, SAP HR-palkanlaskennan kyvykkyyden tarkempaa tutkimisia, vaihtoehtoisten ohjelmien vertailua sekä ennen kaikkea valmiutta muuttaa nykyisiä prosesseja.

Harmonising the Modular Product Range

Työn tavoitteena on analysoida KONEen hissien ovituoteperheitä ja harmonisoida modulaarista ovituotevalikoimaa niin, että tulos olisi mahdollisimman suotuisa KONEelle sekä sen sidosryhmille. Harmonisointi toteutetaan, koska KONEen tuotevalikoima on erittäin laaja ja monimutkainen ja siitä syystä erittäin kallis ja vaikea hallita ja ylläpitää. Tavoitteena on selvittää myös termejä modulaarisuus ja tuotealusta olennaisen kirjallisuuden pohjalta. Nykyään yritysten täytyy kehittää tuotevalikoimaa jatkuvasti. Yrityksen koko tuotevalikoiman varioituvuus tulisi kuitenkin pitää järkevissä rajoissa. Moduuleita ja tuotealustoja pitäisi käyttää jakamaan tuotteiden avainelementtejä ja lisäämään varioituvuutta helposti hallittavalla tavalla. Kannattamattomat ja matalavolyymiset tuotteet kuluttavat yrityksen niukkoja resursseja. Tällaiset tuotteet tulisi poistaa tuotevalikoimasta, mutta ei ilman harkintaa. Kannattama-tonkin tuote voi olla erittäin arvokas asiakkaalle ja tällaisen tuotteen hylkääminen voi olla yritykselle pitkällä tähtäimellä erittäin kohtalokasta. Työn tuloksena oli harmonisointiehdotus KONEen AMD-oville ja selvitys harmonisoinnin vaikutuksista. Harmonisointi KONEella päätettiin toteuttaa siten, että matalavolyymiset tuotteet siirrettiin erikoistuotteiden valikoimaan. Myös kustannusanalyysi tukee harmonisointipäätöstä laskentajärjestelmän puutteista huolimatta.

Computing the persistent homology of range images with alpha shapes

Laser scanning is becoming an increasingly popular method for measuring 3D objects in industrial design. Laser scanners produce a cloud of 3D points. For CAD software to be able to use such data, however, this point cloud needs to be turned into a vector format. A popular way to do this is to triangulate the assumed surface of the point cloud using alpha shapes. Alpha shapes start from the convex hull of the point cloud and gradually refine it towards the true surface of the object. Often it is nontrivial to decide when to stop this refinement. One criterion for this is to do so when the homology of the object stops changing. This is known as the persistent homology of the object. The goal of this thesis is to develop a way to compute the homology of a given point cloud when processed with alpha shapes, and to infer from it when the persistent homology has been achieved. Practically, the computation of such a characteristic of the target might be applied to power line tower span analysis.

Magnetic Resonance Experiments with Atomic Hydrogen

In this thesis three experiments with atomic hydrogen (H) at low temperatures T<1 K are presented. Experiments were carried out with two- (2D) and three-dimensional (3D) H gas, and with H atoms trapped in solid H2 matrix. The main focus of this work is on interatomic interactions, which have certain specific features in these three systems considered. A common feature is the very high density of atomic hydrogen, the systems are close to quantum degeneracy. Short range interactions in collisions between atoms are important in gaseous H. The system of H in H₂ differ dramatically because atoms remain fixed in the H₂ lattice and properties are governed by long-range interactions with the solid matrix and with H atoms. The main tools in our studies were the methods of magnetic resonance, with electron spin resonance (ESR) at 128 GHz being used as the principal detection method. For the first time in experiments with H in high magnetic fields and at low temperatures we combined ESR and NMR to perform electron-nuclear double resonance (ENDOR) as well as coherent two-photon spectroscopy. This allowed to distinguish between different types of interactions in the magnetic resonance spectra. Experiments with 2D H gas utilized the thermal compression method in homogeneous magnetic field, developed in our laboratory. In this work methods were developed for direct studies of 3D H at high density, and for creating high density samples of H in H₂. We measured magnetic resonance line shifts due to collisions in the 2D and 3D H gases. First we observed that the cold collision shift in 2D H gas composed of atoms in a single hyperfine state is much smaller than predicted by the mean-field theory. This motivated us to carry out similar experiments with 3D H. In 3D H the cold collision shift was found to be an order of magnitude smaller for atoms in a single hyperfine state than that for a mixture of atoms in two different hyperfine states. The collisional shifts were found to be in fair agreement with the theory, which takes into account symmetrization of the wave functions of the colliding atoms. The origin of the small shift in the 2D H composed of single hyperfine state atoms is not yet understood. The measurement of the shift in 3D H provides experimental determination for the difference of the scattering lengths of ground state atoms. The experiment with H atoms captured in H2 matrix at temperatures below 1 K originated from our work with H gas. We found out that samples of H in H2 were formed during recombination of gas phase H, enabling sample preparation at temperatures below 0.5 K. Alternatively, we created the samples by electron impact dissociation of H₂ molecules in situ in the solid. By the latter method we reached highest densities of H atoms reported so far, 3.5(5)x10¹⁹ cm^-3. The H atoms were found to be stable for weeks at temperatures below 0.5 K. The observation of dipolar interaction effects provides a verification for the density measurement. Our results point to two different sites for H atoms in H2 lattice. The steady-state nuclear polarizations of the atoms were found to be non-thermal. The possibility for further increase of the impurity H density is considered. At higher densities and lower temperatures it might be possible to observe phenomena related to quantum degeneracy in solid.

Distribution and role of macrophytes in coastal lagoons : implications of critical shifts

Crossroads, crucibles and refuges are three words that may describe natural coastal lagoon environments. The words refer to the complex mix of marine and terrestrial influences, prolonged dilution due to the semi-enclosed nature and the function of a habitat for highly diverse plant and animal communities, some of which are endangered. To attain a realistic picture of the present situation, high vulnerability to anthropogenic impact should be added to the description. As the sea floor in coastal lagoons is usually entirely photic, macrophyte primary production is accentuated compared with open sea environments. There is, however, a lack of proper knowledge on the importance of vegetation for the general functioning of coastal lagoon ecosystems. The aim of this thesis is to assess the role of macrophyte diversity, cover and species identity over temporal and spatial scales for lagoon functions, and to determine which steering factors primarily restrict the qualitative and quantitative composition of vegetation in coastal lagoons. The results are linked to patterns of related trophic levels and the indicative potential of vegetation for assessment of general conditions in coastal lagoons is evaluated. This thesis includes five field studies conducted in flads and glo-flads in the brackish water northern Baltic Sea. Flads and glo-flads are defined as a Baltic variety of coastal lagoons, which due to an inlet threshold and post-glacial landuplift slowly will be isolated from the open sea. This process shrinks inlet size, increases exposure and water retention, and is called habitat isolation. The studied coastal lagoons are situated in the archipelago areas of the eastern coast of Sweden, the Åland Islands and the south-west mainland of Finland, where land-uplift amounts to ca. 5 mm/ per year. Out of 400 evaluated sites, a total of 70 lagoons varying in inlet size, archipelago position and anthropogenic influence to cover for essential environmental variation were chosen for further inventory. Vegetation composition, cover and richness were measured together with several hydrographic and morphometric variables in the lagoons both seasonally and inter-annually to cover for general regional, local and temporal patterns influencing lagoon and vegetation development. On smaller species-level scale, the effects of macrophyte species identity and richness for the fish habitat function were studied by examining the influence of plant interaction on juvenile fish diversity. Thus, the active election of plant monoand polycultures by fish and the diversity of fish in the respective culture were examined and related to plant height and water depth. The lagoons and vegetation composition were found to experience a regime shift initiated by increased habitat isolation along with land-uplift. Vegetation composition altered, richness decreased and cover increased forming a less isolated and more isolated regime, named the vascular plant regime and charophyte regime, respectively according to the dominant vegetation. As total phosphorus in the water, turbidity and the impact of regional influences decreased in parallel, the dominance of charophytes and increasing cover seemed to buffer and stabilize conditions in the charophyte regime and indicated an increased functional role of vegetation for the lagoon ecosystem. The regime pattern was unaffected by geographical differences, while strong anthropogenic impact seemed to distort the pattern due to loss of especially Chara tomentosa L. in the charophyte regime. The regimes were further found unperturbed by short-time temporal fluctuations. In fact the seasonal and inter-annual dynamics reinforced the functional difference between the regimes by the increasing role of vegetation along habitat isolation and the resemblance to lake environments for the charophyte regime. For instance, greater total phosphorus and chlorophyll a concentrations in the water in the beginning of the season in the charophyte regime compared with the vascular plant regime presented a steeper reduction to even lower values than in the vascular plant regime along the season. Despite a regional importance and positive relationship of macrophyte diversity in relation to trophic diversity, species identity was underlined in the results of this thesis, especially with decreasing spatial scale. This result was supported partly by the increased role of charophytes in the functioning of the charophyte regime, but even more explicitly by the species-specific preference of juvenile fish for tall macrophyte monocultures. On a smaller species-level scale, tall plant species in monoculture seemed to be able to increase their length, indicating that negative selection forms preferred habitat structures, which increase fish diversity. This negative relationship between plant and fish diversity suggest a shift in diversity patterns among trohic levels on smaller scale. Thus, as diversity patterns seem complex and diverge among spatial scales, it might be ambiguous to extend the understanding of diversity relationships from one trophic level to the other. All together, the regime shift described here presents similarities to the regime development in marine lagoon environments and shallow lakes subjected to nutrient enrichment. However, due to nutrient buffering by vegetation with increased isolation and water retention as a consequence of the inlet threshold, the development seems opposite to the course along an eutrophication gradient described in marine lagoons lacking an inlet threshold, where the role of vegetation decreases. Thus, the results imply devastating consequences of inlet dredging (decreasing isolation) in terms of vegetation loss and nutrient release, and call for increased conservational supervision. Especially the red listed charophytes would suffer negatively from such interference and the consequences are likely to also deteriorate juvenile fish production. The fact that a new species to Finland, Chara connivens Salzm. Ex. Braun 1835 was discovered during this study further indicates a potential of the lagoons serving as refuges for rare species.

Field Weakening, Parameters and Operation Range of the Permanent Magnet Traction Motors

The main focus of this thesis is to define the field weakening point of permanent magnet synchronous machine with embedded magnets in traction applications. Along with the thesis a modelling program is made to help the designer to define the field weakening point in practical applications. The thesis utilizes the equations based on the current angle. These equations can be derived from the vector diagram of permanent magnet synchronous machine. The design parameters of the machine are: The maximum rotational speed, saliency ratio, maximum induced voltage and characteristic current. The main result of the thesis is finding out the rated rotational speed, from which the field weakening starts. The action of the machine is estimated at a wide speed range and the changes of machine parameters are examined.

Design Aspects of Megawatt-Range Direct-Driven Permanent MagnetWind Generators

Direct-driven permanent magnet synchronous generator is one of the most promising topologies for megawatt-range wind power applications. The rotational speed of the direct-driven generator is very low compared with the traditional electrical machines. The low rotational speed requires high torque to produce megawatt-range power. The special features of the direct-driven generators caused by the low speed and high torque are discussed in this doctoral thesis. Low speed and high torque set high demands on the torque quality. The cogging torque and the load torque ripple must be as low as possible to prevent mechanical failures. In this doctoral thesis, various methods to improve the torque quality are compared with each other. The rotor surface shaping, magnet skew, magnet shaping, and the asymmetrical placement of magnets and stator slots are studied not only by means of torque quality, but also the effects on the electromagnetic performance and manufacturability of the machine are discussed. The heat transfer of the direct-driven generator must be designed to handle the copper losses of the stator winding carrying high current density and to keep the temperature of the magnets low enough. The cooling system of the direct-driven generator applying the doubly radial air cooling with numerous radial cooling ducts was modeled with a lumped-parameter-based thermal network. The performance of the cooling system was discussed during the steady and transient states. The effect of the number and width of radial cooling ducts was explored. The large number of radial cooling ducts drastically increases the impact of the stack end area effects, because the stator stack consists of numerous substacks. The effects of the radial cooling ducts on the effective axial length of the machine were studied by analyzing the crosssection of the machine in the axial direction. The method to compensate the magnet end area leakage was considered. The effect of the cooling ducts and the stack end area effects on the no-load voltages and inductances of the machine were explored by using numerical analysis tools based on the three-dimensional finite element method. The electrical efficiency of the permanent magnet machine with different control methods was estimated analytically over the whole speed and torque range. The electrical efficiencies achieved with the most common control methods were compared with each other. The stator voltage increase caused by the armature reaction was analyzed. The effect of inductance saturation as a function of load current was implemented to the analytical efficiency calculation.