1000 resultados para Parametrisk design
Resumo:
Pro gradu –tutkielman tavoitteena oli tutkia, kuinka palvelumuotoilua voidaan käyttää parempien asiakaskokemusten luomisessa. Tutkimuksen teoreettisessa osuudessa keskityttiin tutkimaan palvelumuotoilun ja asiakaskokemuksen käsitteitä. Tutkielman empiirinen osuus tehtiin laadullisena tutkimuksena, jossa vertailtiin asiakaskokemuksia kahdessa Espoon kaupungin yhteispalvelupisteessä: Leppävaarassa sijaitseva yhteispalvelupiste oli hiljattain suunniteltu uudelleen käyttäen palvelumuotoilun periaatteita; Matinkylän palvelupiste oli alkuperäisessä muodossaan tutkimuksen aikana. Tutkimuksen yhtenä tavoitteena oli myös selvittää, oliko palvelumuotoilun menetelmin tehty muotoiluprojekti Leppävaaran yhteispalvelupisteessä onnistunut, kun sitä arvioitiin asiakaskokemuksen näkökulmasta. Tutkielman aineisto kerättiin suoran havainnoinnin ja haastattelun keinoin. Yhteensä 33 yksittäistä asiakasta havannoitiin ja haastateltiin tutkimusta varten toukokuussa 2015. Vastaajat valikoituivat satunnaisesti havannointipäivien asiakkaista. Heitä havainnoitiin koko asiakaspolun ajan minkä jälkeen heitä haastateltiin. Tutkimuksen tulokset ovat kaksiosaiset. 1) Arvioitaessa asiakkaiden kokemuksia liittyen palvelutilan toimivuuteen ja aineelliseen ympäristöön todettiin, että palvelumuotoilulla saavuttettiin parempi asiakaskokemus, ja täten Leppävaaran muotoiluprojekti oli onnistunut tavoitteissaan. 2) Kun taas tuloksia tarkasteltiin asiakaspalvelutilanteiden näkökulmasta, projekti ei ollut päässyt tavoitteisiin ja palvelumuotoilun menetelmillä ei pystytty parantamaan asiakaskokemuksta. Espoon kaupungin muotoiluprojekti on vielä kesken, tulosten perusteella tutkija ehdotti jatkotoimenpiteenä muun muassa lisäkoulutusta palveluhenkilökunnalle.
Electromagnetic and thermal design of a multilevel converter with high power density and reliability
Resumo:
Electric energy demand has been growing constantly as the global population increases. To avoid electric energy shortage, renewable energy sources and energy conservation are emphasized all over the world. The role of power electronics in energy saving and development of renewable energy systems is significant. Power electronics is applied in wind, solar, fuel cell, and micro turbine energy systems for the energy conversion and control. The use of power electronics introduces an energy saving potential in such applications as motors, lighting, home appliances, and consumer electronics. Despite the advantages of power converters, their penetration into the market requires that they have a set of characteristics such as high reliability and power density, cost effectiveness, and low weight, which are dictated by the emerging applications. In association with the increasing requirements, the design of the power converter is becoming more complicated, and thus, a multidisciplinary approach to the modelling of the converter is required. In this doctoral dissertation, methods and models are developed for the design of a multilevel power converter and the analysis of the related electromagnetic, thermal, and reliability issues. The focus is on the design of the main circuit. The electromagnetic model of the laminated busbar system and the IGBT modules is established with the aim of minimizing the stray inductance of the commutation loops that degrade the converter power capability. The circular busbar system is proposed to achieve equal current sharing among parallel-connected devices and implemented in the non-destructive test set-up. In addition to the electromagnetic model, a thermal model of the laminated busbar system is developed based on a lumped parameter thermal model. The temperature and temperature-dependent power losses of the busbars are estimated by the proposed algorithm. The Joule losses produced by non-sinusoidal currents flowing through the busbars in the converter are estimated taking into account the skin and proximity effects, which have a strong influence on the AC resistance of the busbars. The lifetime estimation algorithm was implemented to investigate the influence of the cooling solution on the reliability of the IGBT modules. As efficient cooling solutions have a low thermal inertia, they cause excessive temperature cycling of the IGBTs. Thus, a reliability analysis is required when selecting the cooling solutions for a particular application. The control of the cooling solution based on the use of a heat flux sensor is proposed to reduce the amplitude of the temperature cycles. The developed methods and models are verified experimentally by a laboratory prototype.
Resumo:
Wind is one of the most compelling forms of indirect solar energy. Available now, the conversion of wind power into electricity is and will continue to be an important element of energy self-sufficiency planning. This paper is one in a series intended to report on the development of a new type of generator for wind energy; a compact, high-power, direct-drive permanent magnet synchronous generator (DD-PMSG) that uses direct liquid cooling (LC) of the stator windings to manage Joule heating losses. The main param-eters of the subject LC DD-PMSG are 8 MW, 3.3 kV, and 11 Hz. The stator winding is cooled directly by deionized water, which flows through the continuous hollow conductor of each stator tooth-coil winding. The design of the machine is to a large degree subordinate to the use of these solid-copper tooth-coils. Both steady-state and timedependent temperature distributions for LC DD-PMSG were examined with calculations based on a lumpedparameter thermal model, which makes it possible to account for uneven heat loss distribution in the stator conductors and the conductor cooling system. Transient calculations reveal the copper winding temperature distribution for an example duty cycle during variable-speed wind turbine operation. The cooling performance of the liquid cooled tooth-coil design was predicted via finite element analysis. An instrumented cooling loop featuring a pair of LC tooth-coils embedded in a lamination stack was built and laboratory tested to verify the analytical model. Predicted and measured results were in agreement, confirming the predicted satisfactory operation of the LC DD-PMSG cooling technology approach as a whole.
Resumo:
This dissertation centres on the themes of knowledge creation, interdisciplinarity and knowledge work. My research approaches interdisciplinary knowledge creation (IKC) as practical situated activity. I argue that by approaching IKC from the practice-based perspective makes it possible to “deconstruct” how knowledge creation actually happens, and demystify its strong intellectual, mentalistic and expertise-based connotations. I have rendered the work of the observed knowledge workers into something ordinary, accessible and routinized. Consequently this has made it possible to grasp the pragmatic challenges as well the concrete drivers of such activity. Thus the effective way of organizing such activities becomes a question of organizing and leading effective everyday practices. To achieve that end, I have conducted ethnographic research of one explicitly interdisciplinary space within higher education, Aalto Design Factory in Helsinki, Finland, where I observed how students from different disciplines collaborated in new product development projects. I argue that IKC is a multi-dimensional construct that intertwines a particular way of doing; a way of experiencing; a way of embodied being; and a way of reflecting on the very doing itself. This places emphasis not only the practices themselves, but also on the way the individual experiences the practices, as this directly affects how the individual practices. My findings suggest that in order to effectively organize and execute knowledge creation activities organizations need to better accept and manage the emergent diversity and complexity inherent in such activities. In order to accomplish this, I highlight the importance of understanding and using a variety of (material) objects, the centrality of mundane everyday practices, the acceptance of contradictions and negotiations well as the role of management that is involved and engaged. To succeed in interdisciplinary knowledge creation is to lead not only by example, but also by being very much present in the very everyday practices that make it happen.
Resumo:
Principen om nationalismen där det politiska och det nationella är samspelt kan vara av markant betydelse för uppbyggande av autonomiska regimer. Likaså tillåter decentralicering och delegering av befogenheter för språk och utbildning (officiellt erkännande av språk, standardisering av språk, undervisningsspråk och relaterade läroplaner) formning av identiteter inom dessa autonomiska regimer. Resultatet är en ofullkomlig cirkulär relation där språk, samfund och politiska institutioner ömsesidigt och kontinuerligt formar varandra: lingvistiskt mångfald prägar och formger autonomiska ordningar och vice-versa. De juridiska implikationerna av territoriella och icke-territoriella former av autonomi är dock av en annan art. Emedan territoriell autonomi bygger på idéen om ett eventuellt inkluderande hemland för lingvistiska grupper, vars vistelseort är avgörande, förstärker den icke-territoriella autonomin idéen om ett exclusivt samfund bestående av själv-identifierade medlemmar som är kapabla till självstyre oavsett territoriella gränser. Denna avhandling utgör an analys av sådana juridiska implikationer genom komparativa och institutionella analyser. Avhandlingen föreslår som resultat en serie av normativa och pragmatiska rekommendationer inriktade på att främja demokratiseringsprocesser i linje med principer om multikulturalism.