Hankintojen kehittäminen ostoerien optimoinnilla

Tutkimuksen tavoitteena on selvittää ostoerien optimoinnilla mahdollisesti saavutettavia kustannussäästöjä ja muita etuja. Talla tarkoitetaan käytännössä yrityksen hankintojen tilausrytmin tiivistämisen mahdollisuuden läpikäymistä. Tutkimuksen empiirisen analyysin tärkein tavoite on selvittää soveltuisiko uusi ostotilausmalli case-yritykselle ja kuinka se vaikuttaisi kustannuksiin. Tutkielman teoriarungossa käsitellään aluksi logistiikan tämän päivän roolia yrityksen arvoketjussa ja logististen toimintojen tehokkuuden mittausta. Teoria osuuden pääpaino on kuitenkin toiminnoissa, joilla hankintoja voidaan kehittää. Naista rajoitutaan varastoinnin kehittämiseen ostoerien optimoinnilla. Empiirisessä osassa käytetään Vaasan & Vaasan Oy:n kustannustiedoista tätä tutkimusta varten muodostettuja raportteja ja muita numeerisia kustannustietoja, joita analysoidaan ostoerien optimointimallin avulla. Tutkimus on kvantitatiivinen analyysi tästä aineistosta. Logistiikan tehokkuus vaikuttaa merkittävästi yrityksen toiminnan tuloksiin, koska hankinnat sitovat merkittävän osan yrityksen pääomasta ja ovat yrityksen suurimpia kulueriä. Teoriassa osoitetaan, että logistiikkaa ja hankintoja kehittämällä ostoerien optimoinnin avulla voidaan vaikuttaa yrityksen toiminnan tehokkuuteen. Empiirisen osan tulosten perusteella ostojen muuttamisella jaksottaiseksi tilaukseksi on vaikutusta toiminnan tehokkuuteen ja sitoutuneisiin pääomiin. Uuden mallin avulla hankintoja sekä logistiikkaa voidaan kehittää lisää, hankintaprosesseja saadaan yksinkertaistettua, voidaan kehittää ostokuljetuksia ja malli tukee yrityksen hankintojen kehittämisen tavoitteita seuraavalle vuodelle.

Kysynnän hallinnan vaikutukset päivittäistavararyhmän kustannustehokkuuteen

Tutkielman konkreettisena tavoitteena oli rakentaa kauppaketjulle kysynnän hallinnan pohjalta malli, jonka avulla ketju voi parantaa asiakaslähtöisyyttään ja samalla tehostaa toimintaansa. Tutkielman teoriaosassa muodostetun viitekehyksen pitävyyttä kokeiltiin TOKMANNI-ketjun makeistuoteryhmään. Tutkielman teoriaosassa seurattiin päivittäistavarakauppaan suunnatun ECR-toiminnan teoreettista viitekehystä, josta saatiin tietoa kirjallisuudesta, konsulttiraporteista sekä artikkeleista. Empiirinen osa toteutettiin kvantitatiivisilla kohdeyrityksen tuottamilla dokumenteilla, joita täydennettiin kvalitatiivisilla haastattelututkimuksilla. Tutkielman pohjalta ketjun makeistuoteryhmään rakennettiin uudelleen määritelty ja yhtenäinen valikoima sekä esillepano. Valikoiman selkiyttämisellä ja yhtenäistämisellä parannettiin tuoteryhmän hallittavuutta sekä helpotettiin henkilökunnan työskentelyä tilaustoiminnassa, esillepanossa ja kampanjoinnissa. Lisäksi tuoteryhmän selkiytymisen ja kulutuskysynnän mukaisen valikoiman nähtiin parantavan myös tuoteryhmän kannattavuutta ja asiakaslähtöisyyttä siisteinä, selkeinä hyllyinä sekä kulutuskysynnän mukaisena valikoimana. Teoreettinen malli tuntui toimivan myös käytännössä.

Management of Exceptions on Access Control Policies

Peer-reviewed

Vacancy-assisted domain-growth in asymmetric binary alloys: A Monte Carlo Study

A Monte Carlo simulation study of the vacancy-assisted domain growth in asymmetric binary alloys is presented. The system is modeled using a three-state ABV Hamiltonian which includes an asymmetry term. Our simulated system is a stoichiometric two-dimensional binary alloy with a single vacancy which evolves according to the vacancy-atom exchange mechanism. We obtain that, compared to the symmetric case, the ordering process slows down dramatically. Concerning the asymptotic behavior it is algebraic and characterized by the Allen-Cahn growth exponent x51/2. The late stages of the evolution are preceded by a transient regime strongly affected by both the temperature and the degree of asymmetry of the alloy. The results are discussed and compared to those obtained for the symmetric case.

Learning Preferences with Kernel-Based Methods

Learning of preference relations has recently received significant attention in machine learning community. It is closely related to the classification and regression analysis and can be reduced to these tasks. However, preference learning involves prediction of ordering of the data points rather than prediction of a single numerical value as in case of regression or a class label as in case of classification. Therefore, studying preference relations within a separate framework facilitates not only better theoretical understanding of the problem, but also motivates development of the efficient algorithms for the task. Preference learning has many applications in domains such as information retrieval, bioinformatics, natural language processing, etc. For example, algorithms that learn to rank are frequently used in search engines for ordering documents retrieved by the query. Preference learning methods have been also applied to collaborative filtering problems for predicting individual customer choices from the vast amount of user generated feedback. In this thesis we propose several algorithms for learning preference relations. These algorithms stem from well founded and robust class of regularized least-squares methods and have many attractive computational properties. In order to improve the performance of our methods, we introduce several non-linear kernel functions. Thus, contribution of this thesis is twofold: kernel functions for structured data that are used to take advantage of various non-vectorial data representations and the preference learning algorithms that are suitable for different tasks, namely efficient learning of preference relations, learning with large amount of training data, and semi-supervised preference learning. Proposed kernel-based algorithms and kernels are applied to the parse ranking task in natural language processing, document ranking in information retrieval, and remote homology detection in bioinformatics domain. Training of kernel-based ranking algorithms can be infeasible when the size of the training set is large. This problem is addressed by proposing a preference learning algorithm whose computation complexity scales linearly with the number of training data points. We also introduce sparse approximation of the algorithm that can be efficiently trained with large amount of data. For situations when small amount of labeled data but a large amount of unlabeled data is available, we propose a co-regularized preference learning algorithm. To conclude, the methods presented in this thesis address not only the problem of the efficient training of the algorithms but also fast regularization parameter selection, multiple output prediction, and cross-validation. Furthermore, proposed algorithms lead to notably better performance in many preference learning tasks considered.

Magnetic and transport properties of InGaAs quantum wells with Mn

In the present work structural, magnetic and transport properties of InGaAs quantum wells (QW) prepared by MBE with an remote Mn layer are investigated. By means of high-resolution X-ray diffractometry the structure of the samples is analyzed. It is shown that Mn ions penetrate into the QW. Influence of the thickness of GaAs spacer and annealing at 286 ºС on the properties of the system is shown. It is shown that annealing of the samples led to Mn activation and narrowing of the Mn layer. Substantial role of 2D holes in ferromagnetic ordering in Mn layer is shown. Evidence for that is observation of maximum at 25 – 55 K on the resistivity temperature dependence. Position of maximum, which is used for quantitative assessment of the Curie temperature, correlates with calculations of the Curie temperature for structures with indirect interaction via 2D holes’ channel. Dependence of the Curie temperature on the spacer thickness shows, that creation of applicable spintronic devices needs high-precision equipment to manufacture extra fine structures. The magnetotransport measurements show that charge carrier mobility is very low. This leads to deficiency of the anomalous Hall effect. At the same time, magnetic field dependences of the magnetization at different temperatures demonstrate that systems are ferromagnetically ordered. These facts, most probably, give evidence of presence of the ferromagnetic MnAs clusters.

Inorganic Nanoparticles and the Immune System: Detection, Selective Activation and Tolerance

The immune system is the responsible for body integrity and prevention of external invasion. On one side, nanoparticles are no triggers that the immune system is prepared to detect, on the other side it is known that foreign bodies, not only bacteria, viruses and parasites, but also inorganic matter, can cause various pathologies such as silicosis, asbestosis or inflammatory reactions. Therefore, nanoparticles entering the body, after interaction with proteins, will be either recognized as self-agents or detected by the immune system, encompassing immunostimulation or immunosuppression responses. The nature of these interactions seems to be dictated not specially by the composition of the material but by modifications of NP coating (composition, surface charge and structure). Herein, we explore the use of gold nanoparticles as substrates to carry multifunctional ligands to manipulate the immune system in a controlled manner, from undetection to immunostimulation. Murine bone marrow macrophages can be activated with artificial nanometric objects consisting of a gold nanoparticle functionalized with peptides. In the presence of some conjugates, macrophage proliferation was stopped and pro-inflammatory cytokines were induced. The biochemical type of response depended on the type of conjugated peptide and was correlated with the degree of ordering in the peptide coating. These findings help to illustrate the basic requirements involved in medical NP conjugate design to either activate the immune system or hide from it, in order to reach their targets before being removed by phagocytes. Additionally, it opens up the possibility to modulate the immune response in order to suppress unwanted responses resulting from autoimmunity, or allergy or to stimulate protective responses against pathogens.

Efeito do tratamento térmico na microestrutura, turbostraticidade e superfície de carbono vítreo reticulado analisado por XPS, espalhamento Raman e voltametria cíclica

The structural and surface properties of reticulated vitreous carbon (RVC) were discussed as a function of its heat treatment temperature (HTT), for samples produced in the range from 700 to 2000 ºC, using the furfuryl precursor resin. The samples were analyzed by x-ray photoelectron spectroscopy, first and second order Raman scattering as well as electrochemical response. Exploring the material turbostraticity concept, the interdependence between the RVC chemical surface variation and its defects were demonstrated. The influence of heteroatom presence was discussed in the material ordering for HTT lower than 1300 ºC while the graphitization process evolution was also pointed out for HTT higher than 1500 ºC.

Desenhos de estruturas químicas correlacionam-se com propriedades biológicas: MIA-QSAR

Descriptors in multivariate image analysis applied to quantitative structure-activity relationship (MIA-QSAR) are pixels of bidimensional images of chemical structures (drawings), which were used to model the trichomonicidal activities of a series of benzimidazole derivatives. The MIA-QSAR model showed good predictive ability, with r², q² and r val. ext.² of 0.853, 0.519 and 0.778, respectively, which are comparable to the best values obtained by CoMFA e CoMSIA for the same series. A MIA-based analysis was also performed by using images of alphabetic letters with the corresponding numeric ordering as dependent variables, but no correlation was found, supporting that MIA-QSAR is not arbitrary.

Hankintaprosessin arviointi ja kehittäminen Case: NCC Rakennus Oy

Tämän tutkimuksen tarkoituksena on löytää keinoja NCC Rakennus Oy:n hankinta- ja tilausprosessien tehostamiseen. Tutkimuksen kohteena ovat projektikohtaisten hankintojen hankintaprosessi, kausisopimuksiin perustuvat tilausprosessit sekä hankintakäytännöt. Tutkimus on toteutettu laadullisena tapaustutkimuksena ja pääasiallisena aineistonkeruumenetelmänä on käytetty teemahaastatteluita. Teemahaastattelujen avulla on pyritty selvittämään kuinka ihmiset ja järjestelmät toimivat prosesseissa ja tunnistamaan eri prosessivaiheiden mahdollisia ongelmakohtia. Mahdolliset ongelmakohdat ja niiden kehitysehdotukset on tässä tutkimuksessa jäsennetty vika- ja vaikutusanalyysin avulla. Saatujen tulosten mukaan hankinta- ja tilausprosessien tehostaminen vaatii muun muassa yhteisten toimintatapojen rakentamista, koulutusta ja yhteistyön kehittämistä eri sidosryhmien kanssa.

Magnetic and transport properties of LaMnO3+δ, La1-xCaxMnO3, La1-xCaxMn1-yFeyO3 and La1-xSrxMn1-yFeyO3

Interest to hole-doped mixed-valence manganite perovskites is connected to the ‘colossal’ magnetoresistance. This effect or huge drop of the resistivity, ρ, in external magnetic field, B, attains usually the maximum value near the ferromagnetic Curie temperature, TC. In this thesis are investigated conductivity mechanisms and magnetic properties of the manganite perovskite compounds LaMnO3+, La1-xCaxMnO3, La1-xCaxMn1-yFeyO3 and La1- xSrxMn1-yFeyO3. When the present work was started the key role of the phase separation and its influence on the properties of the colossal magnetoresistive materials were not clear. Our main results are based on temperature dependencies of the magnetoresistance and magnetothermopower, investigated in the temperature interval of 4.2 - 300 K in magnetic fields up to 10 T. The magnetization was studied in the same temperature range in weak (up to 0.1 T) magnetic fields. LaMnO3+δ is the parent compound for preparation of the hole-doped CMR materials. The dependences of such parameters as the Curie temperature, TC, the Coulomb gap, Δ, the rigid gap, γ, and the localization radius, a, on pressure, p, are observed in LaMnO3+δ. It has been established that the dependences above can be interpreted by increase of the electron bandwidth and decrease of the polaron potential well when p is increased. Generally, pressure stimulates delocalization of the electrons in LaMnO3+δ. Doping of LaMnO3 with Ca, leading to La1-xCaxMnO3, changes the Mn3+/Mn4+ ratio significantly and brings an additional disorder to the crystal lattice. Phase separation in a form of mixture of the ferromagnetic and the spin glass phases was observed and investigated in La1- xCaxMnO3 at x between 0 and 0.4. Influence of the replacement of Mn by Fe is studied in La0.7Ca0.3Mn1−yFeyO3 and La0.7Sr0.3Mn1−yFeyO3. Asymmetry of the soft Coulomb gap and of the rigid gap in the density of localized states, small shift of the centre of the gaps with respect to the Fermi level and cubic asymmetry of the density of states are obtained in La0.7Ca0.3Mn1−yFeyO3. Damping of TC with y is connected to breaking of the double-exchange interaction by doping with Fe, whereas the irreversibility and the critical behavior of the magnetic susceptibility are determined by the phase separation and the frustrated magnetic state of La0.7Sr0.3Mn1−yFeyO3.

Mössbauer spectra of iron oxides in the bulk and nanocrystalline states

Magnetic nanoparticles are very important in modern industry. These particles are used in many different spheres of life. Nanoparticles have unusual physical and chemical properties connected both with quantum dimensional effects and with the increased role of the surface atoms. Most clearly the difference between the properties of bulk materials and nanoparticles can be seen in the magnetic properties of these materials. The most typical magnetic properties of nanomaterials are superparamagnetism with the size of the cluster from 1 to 10 nm; single-domain magnetic state of nanoclusters and nanostructures up to 20 nm; magnetization processes connected with magnetic cluster ordering and with its forms and sizes; quantum magnetic tunneling effects when magnetization changes by jumps and giant magnetoresistance effects. For research of the magnetic properties of iron-containing nanostructures, it is convenient to apply Mӧssbauer spectroscopy. In this work a number of nano-sized samples of iron oxides were examined by Mössbauer spectroscopy. The Mössbauer spectra of nanoparticles with various sizes were obtained. Mössbauer spectra of iron oxide nanoparticles were compared with the spectra of bulk samples. It was shown how the spectra of iron oxide nanoparticles change depending on the particle sizes.

The transcendence of time in the epistemology of observation from a phenomenological standpoint

In this article I deal with time as a notion of epistemological content associated though with the notion of a subjective consciousness co-constitutive of physical reality. In this phenomenologically grounded approach I attempt to establish a 'metaphysical' aspect of time, within a strictly epistemological context, in the sense of an underlying absolute subjectivity which is non-objectifiable within objective temporality and thus non-susceptible of any ontological designation. My arguments stem, on the one hand, from a version of quantum-mechanical theory (History Projection Operator theory, HPO theory) in view of its formal treatment of two different aspects of time within a quantum context. The discrete, partial-ordering properties (the notions of before and after) and the dynamical-parameter properties reflected in the wave equations of motion. On the other hand, to strengthen my arguments for a transcendental factor of temporality, I attempt an interpretation of some relevant conclusions in the work of J. Eccles ([5]) and of certain results of experimental research of S. Deahaene et al. ([2]) and others.

Sähköisten hankintamenettelyjen taloudelliset yritysvaikutukset

Pro gradu -tutkielmassa tutkitaan julkisissa hankinnoissa käyttöön otettavien uusien sähköisten menettelyjen, sähköisen huutokaupan ja dynaamisen hankintajärjestelmän, yritysvaikutuksia. Ydintutkimustehtävänä on tutkia, millaisia taloudellisia vaikutuksia sähköisillä menettelyillä tulee olemaan yrityksiin niiden tarjotessa palveluita tai tavaroita julkiselle sektorille ja mitkä ovat sähköisten menettelyjen käytön motiivit. Tutkielman teoriaosa on pohja empiiriselle tutkimukselle, jossa aineistona on käytetty suppeaa kyselytutkimusta, haastatteluja ja lisäksi materiaalia on tuotettu analysoimalla hallinnollisten kustannusten määrää sähköisissä hankintamenettelyissä. Yritysvaikutusten arvioinnissa tarkasteltiin sähköisten hankintamenettelyjen käytön motiiveja. Motiiveiksi tunnistettiin tehokkuuden tavoittelu, kustannussäästöt, ajankäytön ja henkilöresurssien käytön tehostaminen sekä avoimuus. Tutkimuksessa onnistuttiin todentamaan edellä mainittuja tekijöitä taloudellisilla malleilla. Määrälliset ja laadulliset tutkimustulokset osoittavat kokonaisuudessaan tuloksellisella tavalla sähköisten hankintamenettelyjen käytön motiiveita ja vaikutuksia yrityksiin. Sähköisillä hankintamenettelyillä voidaan perustellusti tehostaa hankintaprosessia ja saavuttaa kustannussäästöjä. Monia yleisiä yritysten julkisiin hankintoihin pääsyn esteinä pitämiä seikkoja voitaisiin vähentää tai poistaa käyttämällä sähköisiä hankintoja. Sähköistä huutokauppaa ja dynaamista hankintajärjestelmää koskevan lainsäädännön luodessa puitteet menettelyiden käytölle, tulee menettelyjen käyttöönoton motiivien ja kannustimien riittävyyttä seurata. Hallinnollisten kustannusten väheneminen ja muiden esteiden pieneneminen ei välttämättä synnytä pysyvää kannustinvaikutusta, vaan hankintaprosessia tulee pyrkiä sähköistämään kokonaisvaltaisesti myös muissa hankintalain mukaisissa hankintamenettelyissä ja kilpailuttamisen ulkopuolisissa hankinnan osa-alueissa kuten laskuttaminen, maksatus ja tilaus.

Ferromagnetic properties of pyrolytic nanocarbon

The work reported in this thesis is dedicated to irreversible magnetic properties in pyrolytic nanocarbon samples. Based on atomic force microscope images, the samples consist of carbon clusters with radius 30..120 nm. These are treated as single-domain nanoparticles. Magnetic hysteresis, field cooled, zero field cooled and thermoremanent magnetization measurements were performed using an RF SQUID magnetometer and ferromagnetic behaviour was observed. Analysis suggests that the ferromagnetic ordering is associated with defects in a thin surface layer, whose thickness is independent of particle size. Critical radius for single-domain particles, critical radius for coherent rotation, magnetic layer thickness, distance between elementary magnetic moments, saturation magnetization, exchange stiffness constant and anisotropy energy density are also presented.