6 resultados para ALAS SUPERLATTICES
em Helda - Digital Repository of University of Helsinki
Resumo:
Design embraces several disciplines dedicated to the production of artifacts and services. These disciplines are quite independent and only recently has psychological interest focused on them. Nowadays, the psychological theories of design, also called design cognition literature, describe the design process from the information processing viewpoint. These models co-exist with the normative standards of how designs should be crafted. In many places there are concrete discrepancies between these two in a way that resembles the differences between the actual and ideal decision-making. This study aimed to explore the possible difference related to problem decomposition. Decomposition is a standard component of human problem-solving models and is also included in the normative models of design. The idea of decomposition is to focus on a single aspect of the problem at a time. Despite its significance, the nature of decomposition in conceptual design is poorly understood and has only been preliminary investigated. This study addressed the status of decomposition in conceptual design of products using protocol analysis. Previous empirical investigations have argued that there are implicit and explicit decomposition, but have not provided a theoretical basis for these two. Therefore, the current research began by reviewing the problem solving and design literature and then composing a cognitive model of the solution search of conceptual design. The result is a synthetic view which describes recognition and decomposition as the basic schemata for conceptual design. A psychological experiment was conducted to explore decomposition. In the test, sixteen (N=16) senior students of mechanical engineering created concepts for two alternative tasks. The concurrent think-aloud method and protocol analysis were used to study decomposition. The results showed that despite the emphasis on decomposition in the formal education, only few designers (N=3) used decomposition explicitly and spontaneously in the presented tasks, although the designers in general applied a top-down control strategy. Instead, inferring from the use of structured strategies, the designers always relied on implicit decomposition. These results confirm the initial observations found in the literature, but they also suggest that decomposition should be investigated further. In the future, the benefits and possibilities of explicit decomposition should be considered along with the cognitive mechanisms behind decomposition. After that, the current results could be reinterpreted.
Resumo:
An important challenge in forest industry is to get the appropriate raw material out from the forests to the wood processing industry. Growth and stem reconstruction simulators are therefore increasingly integrated in industrial conversion simulators, for linking the properties of wooden products to the three-dimensional structure of stems and their growing conditions. Static simulators predict the wood properties from stem dimensions at the end of a growth simulation period, whereas in dynamic approaches, the structural components, e.g. branches, are incremented along with the growth processes. The dynamic approach can be applied to stem reconstruction by predicting the three-dimensional stem structure from external tree variables (i.e. age, height) as a result of growth to the current state. In this study, a dynamic growth simulator, PipeQual, and a stem reconstruction simulator, RetroSTEM, are adapted to Norway spruce (Picea abies [L.] Karst.) to predict the three-dimensional structure of stems (tapers, branchiness, wood basic density) over time such that both simulators can be integrated in a sawing simulator. The parameterisation of the PipeQual and RetroSTEM simulators for Norway spruce relied on the theoretically based description of tree structure developing in the growth process and following certain conservative structural regularities while allowing for plasticity in the crown development. The crown expressed both regularity and plasticity in its development, as the vertical foliage density peaked regularly at about 5 m from the stem apex, varying below that with tree age and dominance position (Study I). Conservative stem structure was characterized in terms of (1) the pipe ratios between foliage mass and branch and stem cross-sectional areas at crown base, (2) the allometric relationship between foliage mass and crown length, (3) mean branch length relative to crown length and (4) form coefficients in branches and stem (Study II). The pipe ratio between branch and stem cross-sectional area at crown base, and mean branch length relative to the crown length may differ in trees before and after canopy closure, but the variation should be further analysed in stands of different ages and densities with varying site fertilities and climates. The predictions of the PipeQual and RetroSTEM simulators were evaluated by comparing the simulated values to measured ones (Study III, IV). Both simulators predicted stem taper and branch diameter at the individual tree level with a small bias. RetroSTEM predictions of wood density were accurate. For focusing on even more accurate predictions of stem diameters and branchiness along the stem, both simulators should be further improved by revising the following aspects in the simulators: the relationship between foliage and stem sapwood area in the upper stem, the error source in branch sizes, the crown base development and the height growth models in RetroSTEM. In Study V, the RetroSTEM simulator was integrated in the InnoSIM sawing simulator, and according to the pilot simulations, this turned out to be an efficient tool for readily producing stand scale information about stem sizes and structure when approximating the available assortments of wood products.
Resumo:
There is an ongoing controversy as to which methods in total hip arthroplasty (THA) could provide young patients with best long-term results. THA is an especially demanding operation in patients with severely dysplastic hips. The optimal surgical treatment for these patients also remains controversial. The aim of this study was to evaluate the long-term survival of THA in young patients (<55 years at the time of the primary operation) on a nation-wide level, and to analyze the long-term clinical and radio-graphical outcome of uncemented THA in patients with severely dysplastic joints. Survival of 4661 primary THAs performed for primary osteoarthritis (OA), 2557 primary THAs per-formed for rheumatoid arthritis (RA), and modern uncemented THA designs performed for primary OA in young patients, were analysed from the Finnish Arthroplasty Register. A total of 68 THAs were per-formed in 56 consecutive patients with high congenital hip dislocation between 1989-1994, and 68 THAs were performed in 59 consecutive patients with severely dysplastic hips and a previous Schanz osteotomy of the femur between 1988-1995 at the Orton Orthopaedic Hospital, Helsinki, Finland. These patients underwent a detailed physical and radiographical evaluation at a mean of 12.3 years and 13.0 years postoperatively, respectively. The risk of stem revision due to aseptic loosening in young patients with primary OA was higher for cemented stems than for proximally porous-coated or HA-coated uncemented stems implanted over the 1991-2001 period. There was no difference in the risk of revision between all-poly cemented-cups and press-fit porous-coated uncemented cups implanted during the same period, when the end point was defined as any revision (including exchange of liner). All uncemented stem designs studied in young patients with primary OA had >90% survival rates at 10 years. The Biomet Bi-Metric stem had a 95% (95% CI 93-97) survival rate even at 15 years. When the end point was defined as any revision, 10 year survival rates of all uncemented cup designs except the Harris-Galante II decreased to <80%. In young patients with RA, the risk of stem revision due to aseptic loosening was higher with cemented stems than with proximally porous-coated uncemented stems. In contrast, the risk of cup revision was higher for all uncemented cup concepts than for all-poly cemented cups with any type of cup revision as the end point. The Harris hip score increased significantly (p<0.001) both in patients with high con-genital hip dislocation and in patients with severely dysplastic hips and a previous Schanz osteotomy, treated with uncemented THA. There was a negative Trendelenburg sign in 92% and in 88% of hips, respectively. There were 12 (18%) and 15 (22%) perioperative complications. The rate of survival for the CDH femoral components, with revision due to aseptic loosening as the end point, was 98% (95% CI 97-100) at 10 years in patients with high hip dislocation and 92% (95% CI, 86-99) at 14 years in patients with a previous Schanz osteotomy. The rate of survival for press-fit, porous-coated acetabular components, with revision due to aseptic loosening as the end point, was 95% (95% CI 89-100) at 10 years in patients with high hip dislocation, and 98% (95% CI 89-100) in patients with a previous Schanz osteotomy. When revision of the cup for any reason was defined as the end point, 10 year sur-vival rates declined to 88% (95% CI 81-95) and to 69% (95% CI, 56-82), respectively. For young patients with primary OA, uncemented proximally circumferentially porous- and HA-coated stems are the implants of choice. However, survival rates of modern uncemented cups are no better than that of all-poly cemented cups. Uncemented proximally circumferentially porous-coated stems and cemented all-poly cups are currently the implants of choice for young patients with RA. Uncemented THA, with placement of the cup at the level of the true acetabulum, distal advancement of the greater trochanter and femoral shortening osteotomy provided patients with high congenital hip dislocation good long-term outcomes. Most of the patients with severely dysplastic hips and a previous Schanz osteotomy can be successfully treated with the same method. However, the subtrochanteric segmental shortening with angular correction gives better leg length correction for the patients with a previous low-seated unilateral Schanz osteotomy.
Resumo:
By detecting leading protons produced in the Central Exclusive Diffractive process, p+p → p+X+p, one can measure the missing mass, and scan for possible new particle states such as the Higgs boson. This process augments - in a model independent way - the standard methods for new particle searches at the Large Hadron Collider (LHC) and will allow detailed analyses of the produced central system, such as the spin-parity properties of the Higgs boson. The exclusive central diffractive process makes possible precision studies of gluons at the LHC and complements the physics scenarios foreseen at the next e+e− linear collider. This thesis first presents the conclusions of the first systematic analysis of the expected precision measurement of the leading proton momentum and the accuracy of the reconstructed missing mass. In this initial analysis, the scattered protons are tracked along the LHC beam line and the uncertainties expected in beam transport and detection of the scattered leading protons are accounted for. The main focus of the thesis is in developing the necessary radiation hard precision detector technology for coping with the extremely demanding experimental environment of the LHC. This will be achieved by using a 3D silicon detector design, which in addition to the radiation hardness of up to 5×10^15 neutrons/cm2, offers properties such as a high signal-to- noise ratio, fast signal response to radiation and sensitivity close to the very edge of the detector. This work reports on the development of a novel semi-3D detector design that simplifies the 3D fabrication process, but conserves the necessary properties of the 3D detector design required in the LHC and in other imaging applications.
Resumo:
Tutkielmassa tarkastellaan osallistuvaa demokratiaa ja kansalaiskuulemista sosiaali-ja terveyspolitiikan kehyksissä. Tutkittava tapaus on sosiaali-ja terveyspalvelulta kehittämään pyrkivä Kuntien parhaat palvelukäytännöt -hanke, joka on räätälöity vauhdittamaan vuonna 2005 käynnistettyä Paras-hanketta. Paras-hankkeessa on kyse sekä kuntien ja valtion vallanjaosta että palvelujärjestelmän kehittämisestä. Kuntien parhaat palvelukäytännöt - hankkeen päämäärä on ollut kehittää sosiaali- ja terveyspalvelulta eri tuottajatoimijöiden kesken. Hankkeiden taustalla vaikuttavat niin uuden julkisjohtamisen ja julkispalvelun eli governance poliittishallinnolliset ideologiat. Tutkittava aineisto koostuu kolmesta osasta: 1) keskusteluista otakantaa-foorumilla a) Parempia sosiaali- ja terveyspalvelulta - miten ja millaisin toimenpitein? sekä b) Miten kehittää kuntien, yksityisen ja kolmannen sektorin yhteistyötä?, 2) virkamiesten laatimasta yhteenvedosta keskustelusta a) ja 3) virkamieshaastatteluista. Aineistoa tarkastellaan sosiaalisen konstruktivismin teoreettismetodologisesta viitekehyksestä. Metodeina käytetään kriittistä diskurssianalyysiä, teoreettista sisällönanalyysiä sekä kehysanalyysiä. Tutkimuksen yleisenä viitekehyksenä toimivat poliittis-ideologiset hallinnolliset muutokset sekä konfliktikeskeinen deliberatiivinen demokratiateoria (Rosanvalion 2008). Tarkennettuna viitekehyksenä toimii osallistuva ja itsepalvelupolitiikka ja epäpolitisoiva ja politisoiva keskustelu niiden kehyksissä.Tutkimus osoittaa keskustelu sosiaali- ja terveyspalveluiden kehittämisestä on etenkin virkamiesten osalta epäpolitisoivaa. Uudistuksia käsitellään teknisinä ratkaisuina, ei poliittisina valintoina. Kansalaiskeskustelusta välittyy poliittisempia sävyjä, mitkä eivät kuitenkaan välity ylhäältä alas -ohjatulla keskustelulla. Kansalaisten ja virkamiesten välinen suhde ei ole hankkeessa vuorovaikutteinen, joten keskustelun ei voida kutsua osallistuvaksi demokratiaksi, vaan kansalaiskuulemiseksi. Tutkimus osoittaa myös, että tutkittua kansalaiskuulemista voidaan tarkastella itsepalveludemokratian viitekehyksestä. Markkinaohjautuvan sosiaali- ja terveyspolitiikan kehyksissä kansalaiset näyttäytyvät asiakas-subjekteina ja demokratian sovellukset kuten otakantaa.fi -foorumi edustavat hankkeen osalta ylhäältä alas -johdettua konsultaatiodemokratiaa, jolloin foorumin rooli demokraattisen keskustelun laajentamisessa jää vähäiseksi.
Resumo:
Tutkimuksessa tarkastellaan mitkä tekijät ovat sähköisen hallinnon kehittämisen ongelmakohtia muutosjohtamisen teorian valossa ja miten julkisen hallinnon konstruktiot vaikuttavat muutosjohtamiseen liittyviin valintoihin sähköisen hallinnon kehittämisessä. Tutkimuksen kohteena on julkisen hallinnon IT-organisaation rakenne ja sähköisen muutoksen johtaminen julkisessa hallinnossa. Tutkimuksessa tarkastellaan muutosjohtamista rakennenäkökulmasta. Gareth Morganin esittämien organisaatiometaforien kautta selvitetään julkisen hallinnon konstruktioiden ja toimintatapojen vaikutusta hallita muutosta, sekä sitä millaisia vaateita sähköinen muutos luo muutosjohtamiselle julkisessa hallinnossa. Tutkimuksessa pyritään vastaamaan kysymykseen: Miten julkisen hallinnon organisaatiorakenne vaikuttaa julkisen hallinnon sähköisen muutoksen johtamiseen? Tutkimus rakentuu kahden pääteeman ympärille, jotka ovat sähköinen hallinto ja muutosjohtaminen. Sähköisen hallinnon pääteema on jaettu kahteen alateemaan sähköiseen demokratiaan sekä sähköiseen identiteettiin, nämä ovat kansalaisille näkyviä sähköisen hallinnon osa-alueita. Sähköisen hallinnon kannalta oleelliset hallinnon sisäiset prosessit, tietojärjestelmät ja julkisyhteisöjen väliset tiedonsiirrot ovat perusta koko sähköisen hallinnon kehittämiselle, ja siksi tutkimuksessa esitellään myös tätä osa-aluetta sähköisestä hallinnosta. Tutkimuksen tieteenfilosofisena lähtökohtana toimii Peter L. Bergerin ja Thomas Luckmannin sosiaalinen konstruktivismi, jonka mukaan todellisuutemme on sosiaalisesti rakentunut. Teoreettisena viitekehyksenä toimii Gareth Morganin organisaatiometaforateoria, joista analyysin tueksi on nostettu konemetafora, poliittinen systeemi -metafora, organismimetafora ja epävakaisuus ja muuttuminen -metafora sekä Cameronin ja Greenin esittelemät muutosjohtamisen mallit, joista analyysin apuna toimii Lewinin kolmen askeleen mallin, Bridgesin johdetun siirtymisen mallin ja Carnallin muutoksen hallintamallin. Tutkimuksen lähestymistapana ja metodina toimii tapaustutkimus, jonka avulla luodaan tutkimuksen kohteesta mahdollisimman selkeä käsitys, ottaen huomioon tutkimuskohteen yhteiskunnallinen ympäristö. Tutkimuksen perusteella voidaan sanoa, että julkisen hallinnon organisaatio rakenteen konemetaforamaiset piirteet vaikuttavat edelleen sähköisen muutoksen johtamiseen julkisessa hallinnossa, ja sähköisen muutoksen johtaminen julkisessa hallinnossa perustuu vahvaan ylhäältä alas kulkevaan konserniohjaukseen. Sähköisen demokratian sekä sähköisen identiteetin ja sähköisten palveluiden kehittäminen vaatii julkiselta hallinnolta vahvaa keskitettyäkin ohjaamista, jotta palveluista voitaisiin kehittää yhdenmukaisia ja helposti käytettäviä. Toisaalta julkisen hallinnon tulee kuitenkin laajentaa näkökulmaansa, jotta sähköisestä hallinnosta saataisiin siihen liittyvä potentiaali kokonaisuudessaan käyttöön. Julkisen hallinnon toimintakentän dynamiikan lisääntyminen voidaan huomioida muutosjohtamisen osalta, ottamalla käyttöön sellaisia muutosjohtamisen malleja ja käytäntöjä, jotka soveltuvat paremmin sähköisen muutoksen johtamisen haasteisiin. Tällaisia ovat ne mallit, jotka ottavat huomioon julkisen hallinnon poliittisen systeemin dynamiikan nopeutumisen, sähköisen hallinnon kehittämisen vaativan kokonaisvaltaisen muutoksen julkisessa organisaatiossa sekä julkisen organisaation rajojen hämärtymisen sähköistä hallintoa kehitettäessä.