914 resultados para Visual-system Model
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Työn tavoitteena oli selvittää kaupallisen dynamiikan simulointiohjelmiston soveltuvuus kallioporakoneen dynamiikan analysointiin. Työssä mallinnettiin parametrisoitu virtuaaliprototyyppi uudenlaisella toimintaperiaatteella toimivasta kallioporakoneesta. Virtuaaliprototyyppiä on tarkoitus käyttää fyysisen prototyypin mitoituksessa sekä porakoneen toiminnan simuloinnissa ja suorituskyvyn arvioinnissa ennen ensimmäisen fyysisen prototyypin valmistamista. Mallinnus tehtiin ADAMS -ohjelmistoa ja siihen liitettävää ADAMS/Hydraulics -moduulia käyttäen. Mallinnuksessa kiinnitettiin huomiota erityisesti porakoneessa esiintyvien vuotovirtauksien huomioimiseen. ADAMS -ohjelmisto soveltuu hyvin hydraulisen iskuporakoneen dynaamisten ilmiöiden simulointiin. Koska fyysistä prototyyppiä ei ole vielä olemassa, ei mallin toimintaa voida kuitenkaan tämän tutkimuksen puitteissa verifioida mittauksin. Simuloitujen tulosten perusteella voidaan todeta uuden toimintaperiaatteen olevan käyttökelpoinen kallion poraukseen. Parametrisoitua virtuaaliprototyyppiä voidaan käyttää tehokkaasti hyväksi tuotekehitysvaiheessa sekä se voidaan liittää osaksi laajempaa ja yksityiskohtaisempaa porauslaitteen simulointimallia.
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Yhtenäistetty mallinnuskieli, Unified Modeling Language (UML), on saavuttanut ohjelmistoteollisuudessa defacto standardin mallinnuskielen aseman. UML:n pääasiallinen käyttökohde on ollut ohjelmistojärjestelmien mallinnus, mutta sitä on sovellettu myös muillakin ongelma-alueilla, kuten erilaisten prosessien mallinnuksessa. Tässä diplomityössä mallinnetaan eräs betoniaseman ohjausjärjestelmä käyttäen UML:ää. Työssä perehdytään alan kirjallisuuden avulla siihen, miten teollisuus on hyödyntänyt UML:ää prosessien ohjausjärjestelmien mallinnuksessa. Kirjallisuudesta saatua tietoa sovelletaan betoniaseman ohjausjärjestelmän mallinnuksessa. Luotua mallia analysoidaan sen oikeellisuuden ja käytettävyyden perusteella. Työssä havaittiin, että UML soveltuu hyvin betoniaseman ohjausjärjestelmän kaltaisen teollisuusprosessin ohjauksen mallinnukseen. UML-mallilla voidaan kuvata järjestelmän rakenne ja toiminta kattavasti. Luotua mallia voidaan hyödyntää suoraan ohjausjärjestelmän jatkokehityksessä. Julkista tutkimustietoa aiheesta on kuitenkin niukasti saatavilla, joten lisätarve julkiselle tutkimukselle on olemassa.
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A pair of recent studies shows that congenital blindness can have significant consequences for the functioning of the visual system after sight restoration, particularly if that restoration is delayed.
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Disease-causing variants of a large number of genes trigger inherited retinal degeneration leading to photoreceptor loss. Because cones are essential for daylight and central vision such as reading, mobility, and face recognition, this review focuses on a variety of animal models for cone diseases. The pertinence of using these models to reveal genotype/phenotype correlations and to evaluate new therapeutic strategies is discussed. Interestingly, several large animal models recapitulate human diseases and can serve as a strong base from which to study the biology of disease and to assess the scale-up of new therapies. Examples of innovative approaches will be presented such as lentiviral-based transgenesis in pigs and adeno-associated virus (AAV)-gene transfer into the monkey eye to investigate the neural circuitry plasticity of the visual system. The models reported herein permit the exploration of common mechanisms that exist between different species and the identification and highlighting of pathways that may be specific to primates, including humans.
Resumo:
Tutkimuksen päätavoite oli kehittää suorituskyvyn analysointijärjestelmä metalliteollisuuden alihankintaa suorittavalle pk-yritykselle. Lisäksi tutkittiin toimintatapoja, jotka edesauttavat menestyksekkään analysointijärjestelmän rakentamista. Tutkimuksessa käsiteltiin myös mittausjärjestelmän hyötyjä ja haittoja pk-yritykselle. Tutkimuksen teoreettisessa osassa käsitellään yleisesti suorituskykyä, esitellään erilaisia suorituskyvyn analysointijärjestelmiä ja selvitetään järjestelmien eroja. Lisäksi esitellään erilaisia prosessimalleja, joiden avulla yritys voi rakentaa suorituskyvyn analysointijärjestelmän. Tutkimuksen empiirisessä osassa esitellään yrityksessä läpikäyty prosessimalli, jonka avulla rakennettiin suorituskyvyn analysointijärjestelmä. Yrityksessä läpikäydyn prosessin pohjana toimi SAKE-prosessimalli, mutta ideoita haettiin myös Toivasen mallista. Tutkimuksen tuloksena syntyi teoreettinen paketti suorituskyvyn analysoinnista ja malli suorituskyvyn analysointijärjestelmästä. Teoreettinen paketti toimi hyvänä pohjana ja tarjosi taustatietoa aiheesta projektissa mukana olleille henkilöille. Tutkimuksen tuloksena syntynyt malli soveltuu parhaiten metallin mekaanista työstöä suorittavalle yritykselle, mutta myös muut yritykset voivat ottaa tästä mallia. Hyödyllisimmäksi näkökulmaksi voi nostaa itse prosessin, jonka avulla päästään tarkastelemaan yrityksen menestymisen taustalla olevia tekijöitä.
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The aim of the thesis is to study the principles of the permanent magnet linear synchronous motor (PMLSM) and to develop a simulator model of direct force controlled PMLSM. The basic motor model is described by the traditional two-axis equations. The end effects, cogging force and friction model are also included into the final motor model. Direct thrust force control of PMLSM is described and modelled. The full system model is proven by comparison with the data provided by the motor manufacturer.
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Tämän diplomityön tavoitteena oli analysoida Stora Enson palkkakeskuksen ja sen henkilöstöhallinnon järjestelmän, SAP HR:n, kustannustehokkuutta ja suorituskykyä. Tutkimuksessa käytettiin apuna benchmarkingia. Viisi suurta suomalaisyritystä osallistui benchmarkingiin. Benchmarkingin pääkohteena oli yritysten välinen kustannusvertailu. Kyselyssä perehdyttiin myös yritysten järjestelmien suorituskykyyn. Tuloksien perusteella Stora Enson palkkakeskus tarjoaa kustannustehokkaan ja kilpailukykyisen ratkaisun, joka menestyy hyvin vertailussa muihin suomalaisiin yrityksiin.
Centralized Motion Control of a Linear Tooth Belt Drive: Analysis of the Performance and Limitations
Resumo:
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.
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The present dissertation examined reading development during elementary school years by means of eye movement tracking. Three different but related issues in this field were assessed. First of all, the development of parafoveal processing skills in reading was investigated. Second, it was assessed whether and to what extent sublexical units such as syllables and morphemes are used in processing Finnish words and whether the use of these sublexical units changes as a function of reading proficiency. Finally, the developmental trend in the speed of visual information extraction during reading was examined. With regard to parafoveal processing skills, it was shown that 2nd graders extract letter identity information approx. 5 characters to the right of fixation, 4th graders approx. 7 characters to the right of fixation, and 6th graders and adults approx. 9 characters to the right of fixation. Furthermore, it was shown that all age groups extract more parafoveal information within compound words than across adjectivenoun pairs of similar length. In compounds, parafoveal word information can be extracted in parallel with foveal word information, if the compound in question is of high frequency. With regard to the use of sublexical units in Finnish word processing, it was shown that less proficient 2nd graders use both syllables and morphemes in the course of lexical access. More proficient 2nd graders as well as older readers seem to process words more holistically. Finally, it was shown that 60 ms is enough for 4th graders and adults to extract visual information from both 4-letter and 8-letter words, whereas 2nd graders clearly needed more than 60 ms to extract all information from 8- letter words for processing to proceed smoothly. The present dissertation demonstrates that Finnish 2nd graders develop their reading skills rapidly and are already at an adult level in some aspects of reading. This is not to say that there are no differences between less proficient (e.g., 2nd graders) and more proficient readers (e.g., adults) but in some respects it seems that the visual system used in extracting information from the text is matured by the 2nd grade. Furthermore, the present dissertation demonstrates that the allocation of attention in reading depends much on textual properties such as word frequency and whether words are spatially unified (as in compounds) or not. This flexibility of the attentional system naturally needs to be captured in word processing models. Finally, individual differences within age groups are quite substantial but it seems that by the end of the 2nd grade practically all Finnish children have reached a reasonable level of reading proficiency.
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The determination of volumetric water content of soils is an important factor in irrigation management. Among the indirect methods for estimating, the time-domain reflectometry (TDR) technique has received a significant attention. Like any other technique, it has advantages and disadvantages, but its greatest disadvantage is the need of calibration and high cost of acquisition. The main goal of this study was to establish a calibration model for the TDR equipment, Trase System Model 6050X1, to estimate the volumetric water content in a Distroferric Red Latosol. The calibration was carried out in a laboratory with disturbed soil samples under study, packed in PVC columns of a volume of 0.0078m³. The TDR probes were handcrafted with three rods and 0.20m long. They were vertically installed in soil columns, with a total of five probes per column and sixteen columns. The weightings were carried out in a digital scale, while daily readings of dielectric constant were obtained in TDR equipment. The linear model θν = 0.0103 Ka + 0.1900 to estimate the studied volumetric water content showed an excellent coefficient of determination (0.93), enabling the use of probes in indirect estimation of soil moisture.
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The pumping processes requiring wide range of flow are often equipped with parallelconnected centrifugal pumps. In parallel pumping systems, the use of variable speed control allows that the required output for the process can be delivered with a varying number of operated pump units and selected rotational speed references. However, the optimization of the parallel-connected rotational speed controlled pump units often requires adaptive modelling of both parallel pump characteristics and the surrounding system in varying operation conditions. The available information required for the system modelling in typical parallel pumping applications such as waste water treatment and various cooling and water delivery pumping tasks can be limited, and the lack of real-time operation point monitoring often sets limits for accurate energy efficiency optimization. Hence, alternatives for easily implementable control strategies which can be adopted with minimum system data are necessary. This doctoral thesis concentrates on the methods that allow the energy efficient use of variable speed controlled parallel pumps in system scenarios in which the parallel pump units consist of a centrifugal pump, an electric motor, and a frequency converter. Firstly, the suitable operation conditions for variable speed controlled parallel pumps are studied. Secondly, methods for determining the output of each parallel pump unit using characteristic curve-based operation point estimation with frequency converter are discussed. Thirdly, the implementation of the control strategy based on real-time pump operation point estimation and sub-optimization of each parallel pump unit is studied. The findings of the thesis support the idea that the energy efficiency of the pumping can be increased without the installation of new, more efficient components in the systems by simply adopting suitable control strategies. An easily implementable and adaptive control strategy for variable speed controlled parallel pumping systems can be created by utilizing the pump operation point estimation available in modern frequency converters. Hence, additional real-time flow metering, start-up measurements, and detailed system model are unnecessary, and the pumping task can be fulfilled by determining a speed reference for each parallel-pump unit which suggests the energy efficient operation of the pumping system.
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Tutkimuksen tavoitteena oli kehittää mallimittaristo logistiikkapalvelualalla toimivan yrityksen operatiivisen tason suorituskyvyn seurantaan ja toiminnanohjausta varten, päivittäisen johtamisen tueksi. Tutkimus suoritettiin pääosin toiminta-analyyttisena, yhden yrityksen empiirisenä tapaustutkimuksena. Tutkimuksen kohdeyrityksen toiminnanmittaus perustuu tällä hetkellä pääasiassa taloudellisiin mittareihin ja muutamaan kyselyyn. Toiminnanohjauksen ja – kehittämisen, päätöksenteon tueksi tarvitaan, taloudellisten mittareiden lisäksi, mittareita, joilla pystytään seuraamaan suorituskyvyn taustalla vaikuttavien tekijöiden kehittymistä. Tutkimuksen kohdeyrityksen operatiivisen tason suorituskyvyn mallimittariston suunnittelussa haluttiin varmistaa, että jatkossa mittaamisella vaikutettaisiin seuraustekijöiden lisäksi myös syytekijöihin, selkiyttää liiketoiminnan tavoitteet, operatiivisen tason näkökulmasta, ja mittaamisen tavoite. Tutkimuksessa esitelty mallimittaristo on suunniteltu, tasapainotetun mittariston viitekehyksen avulla. Mittariston näkökulmiksi valittiin: talous, sidosryhmä (asiakas), prosessi ja henkilöstö. Mittariston tuottaman tiedon tavoitteena on toiminnanohjauksen, -kehittämisen ja päätöksenteon tukeminen, kun mittaustulokset ja trendi ovat yhdessä paikassa, on tiedonhaku ja - hyödyntäminen helpompaa. Mallimittaristoa ei testattu eikä käyttöönotettu tutkimuksessa.
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We measured human frequency response functions for seven angular frequency filters whose test frequencies were centered at 1, 2, 3, 4, 8, 16 or 24 cycles/360º using a supra-threshold summation method. The seven functions of 17 experimental conditions each were measured nine times for five observers. For the arbitrarily selected filter phases, the maximum summation effect occurred at test frequency for filters at 1, 2, 3, 4 and 8 cycles/360º. For both 16 and 24 cycles/360º test frequencies, maximum summation occurred at the lower harmonics. These results allow us to conclude that there are narrow-band angular frequency filters operating somehow in the human visual system either through summation or inhibition of specific frequency ranges. Furthermore, as a general result, it appears that addition of higher angular frequencies to lower ones disturbs low angular frequency perception (i.e., 1, 2, 3 and 4 cycles/360º), whereas addition of lower harmonics to higher ones seems to improve detection of high angular frequency harmonics (i.e., 8, 16 and 24 cycles/360º). Finally, we discuss the possible involvement of coupled radial and angular frequency filters in face perception using an example where narrow-band low angular frequency filters could have a major role.
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Glutamate receptors have been often associated with developmental processes. We used immunohistochemical techniques to evaluate the expression of the AMPA-type glutamate receptor (GluR) subunits in the chick optic tectum (TeO). Chick embryos from the 5th through the 20th embryonic day (E5-E20) and one-day-old (P1) chicks were used. The three types of immunoreactivity evaluated (GluR1, GluR2/3, and GluR4) had different temporal and spatial expression patterns in the several layers of the TeO. The GluR1 subunit first appeared as moderate staining on E7 and then increased on E9. The mature GluR1 pattern included intense staining only in layer 5 of the TeO. The GluR2/3 subunits presented low expression on E5, which became intense on E7. The staining for GluR2/3 changed to very intense on E14 in tectal layer 13. Staining of layer 13 neurons is the most prominent feature of GluR immunoreactivity in the adult TeO. The GluR4 subunit generally presented the lowest expression starting on E7, which was similar to the adult pattern. Some instances of transient expression of GluR subunits were observed in specific cell populations from E9 through E20. These results demonstrate a differential expression of the GluR subunits in the embryonic TeO, adding information about their possible functions in the developmental processes of the visual system.
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We measured human contrast sensitivity to radial frequencies modulated by cylindrical (Jo) and spherical (j o) Bessel profiles. We also measured responses to profiles of j o, j1, j2, j4, j8, and j16. Functions were measured three times by at least three of eight observers using a forced-choice method. The results conform to our expectations that sensitivity would be higher for cylindrical profiles. We also observed that contrast sensitivity is increased with the j n order for n greater than zero, having distinct orderly effects at the low and high frequency ends. For n = 0, 1, 2, and 4 sensitivity tended to occur around 0.8-1.0 cpd while for n = 8 and 16 it seemed to shift gradually to 0.8-3.0 cpd. We interpret these results as being consistent with the possibility that spatial frequency processing by the human visual system can be defined a priori in terms of polar coordinates and discuss its application to study face perception.