Multibody Simulation Model of the Roller Test Rig

Multibody simulation model of the roller test rig is presented in this work. The roller test rig consists of a paper machine’s tube roll supported with a hard bearing type balancing machine. The simulation model includes non-idealities that are measured from the physical structure. These non-idealities are the shell thickness variation of the roll and roundness errors of the shafts of the roll. These kinds of non-idealities are harmful since they can cause subharmonic resonances of the rotor system. In this case, the natural vibration mode of the rotor is excited when the rotation speed is a fraction of the natural frequency of the system. With the simulation model, the half critical resonance is studied in detail and a sensitivity analysis is performed by simulating several analyses with slightly different input parameters. The model is verified by comparing the simulation results with those obtained by measuring the real structure. Comparison shows that good accuracy is achieved, since equivalent responses are achieved within the error limit of the input parameters.

Matched case-control study evaluating the frequency of the main agents associated with neonatal diarrhea in piglets

A case-control study was carried out in litters of 1 to 7-day-old piglets to identify the main infectious agents involved with neonatal diarrhea in pigs. Fecal samples (n=276) from piglets were collected on pig farms in the State of Rio Grande do Sul, Brazil, from May to September 2007. Litters with diarrhea were considered cases (n=129) and normal litters (n=147) controls. The samples were examined by latex agglutination test, PAGE, conventional isolating techniques, ELISA, PCR, and microscopic methods in order to detect rotavirus, bacterial pathogens (Escherichia coli, Clostridium perfringens type A and C, and Clostridium difficile), and parasites (Coccidian and Cryptosporidium spp.). Outbreaks of diarrhea were not observed during sampling. At least one agent was detected in fecal samples on 25 out of 28 farms (89.3%) and in 16 farms (57.1%) more than one agent was found. The main agents diagnosed were Coccidia (42.86%) and rotavirus (39.29%). The main agents identified in litters with diarrhea were Clostridium difficile (10.6%), Clostridium perfringens type A (8.8%) and rotavirus (7.5%); in control litters, Clostridium difficile (16.6%) and Coccidian (8.5%). Beta hemolytic Escherichia coli and Clostridium perfringens type C were not detected. When compared with controls, no agent was significantly associated with diarrhea in case litters. These findings stress the need for caution in the interpretation of laboratorial diagnosis of mild diarrhea in neonatal pigs, as the sole detection of an agent does not necessarily indicate that it is the cause of the problem.

Cost-benefit analysis of using test automation in the development of embedded software

The goal of this thesis is to make a case study of test automation’s profitability in the development of embedded software in a real industrial setting. The cost-benefit analysis is done by considering the costs and benefits test automation causes to software development, before the software is released to customers. The potential benefits of test automation regarding software quality after customer release were not estimated. Test automation is a significant investment which often requires dedicated resources. When done accordingly, the investment in test automation can produce major cost savings by reducing the need for manual testing effort, especially if the software is developed with an agile development framework. It can reduce the cost of avoidable rework of software development, as test automation enables the detection of construction time defects in the earliest possible moment. Test automation also has many pitfalls such as test maintainability and testability of the software, and if those areas are neglected, the investment in test automation may become worthless or it may even produce negative results. The results of this thesis suggest that test automation is very profitable at the company under study.

Reaching influential early adopters effectively in Finland : Rock Science – new generation board game

Innovations diffuse at different speed among the members of a social system through various communication channels. The group of early adopters can be seen as the most influential reference group for majority of people to base their innovation adoption decisions on. Thus, the early adopters can often accelerate the diffusion of innovations. The purpose of this research is to discover means of diffusion for an innovative product in Finnish market through the influential early adopters in respect to the characteristics of the case product. The purpose of the research can be achieved through the following sub objectives:  Who are the potential early adopters for the case product and why?  How the potential early adopters of the case product should be communicated with?  What would be the expectations, preferences, and experiences of the early adopters of the case product? The case product examined in this research is a new board game called Rock Science which is considered to be incremental innovation bringing board gaming and hard rock music together in a new way. The research was conducted in two different parts using both qualitative and quantitative research methods. This mixed method research began with expert interviews of six music industry experts. The information gathered from the interviews enabled researcher to compose the questionnaire for the quantitative part of the study. Internet survey that was sent out resulted with a sample of 97 responses from the targeted population. The key findings of the study suggest that (1) the potential early adopters for the case product are more likely to be young adults from the capital city area with great interest in rock music, (2) the early adopters can be reached effectively through credible online sources of information, and (3) the respondents overall product feedback is highly positive, except in the case of quality-price ratio of the product. This research indicates that more effective diffusion of Rock Science board game in Finland can be reached through (1) strategic alliances with music industry and media partnerships, (2) pricing adjustments, (3) use of supporting game formats, and (4) innovative use of various social media channels.

Energy and raw material consumption analysis of powder bed fusion: case study: CNC machining and laser additive manufacturing

Laser additive manufacturing (LAM), known also as 3D printing, is a powder bed fusion (PBF) type of additive manufacturing (AM) technology used to manufacture metal parts layer by layer by assist of laser beam. The development of the technology from building just prototype parts to functional parts is due to design flexibility. And also possibility to manufacture tailored and optimised components in terms of performance and strength to weight ratio of final parts. The study of energy and raw material consumption in LAM is essential as it might facilitate the adoption and usage of the technique in manufacturing industries. The objective this thesis was find the impact of LAM on environmental and economic aspects and to conduct life cycle inventory of CNC machining and LAM in terms of energy and raw material consumption at production phases. Literature overview in this thesis include sustainability issues in manufacturing industries with focus on environmental and economic aspects. Also life cycle assessment and its applicability in manufacturing industry were studied. UPLCI-CO2PE! Initiative was identified as mostly applied exiting methodology to conduct LCI analysis in discrete manufacturing process like LAM. Many of the reviewed literature had focused to PBF of polymeric material and only few had considered metallic materials. The studies that had included metallic materials had only measured input and output energy or materials of the process and compared to different AM systems without comparing to any competitive process. Neither did any include effect of process variation when building metallic parts with LAM. Experimental testing were carried out to make dissimilar samples with CNC machining and LAM in this thesis. Test samples were designed to include part complexity and weight reductions. PUMA 2500Y lathe machine was used in the CNC machining whereas a modified research machine representing EOSINT M-series was used for the LAM. The raw material used for making the test pieces were stainless steel 316L bar (CNC machined parts) and stainless steel 316L powder (LAM built parts). An analysis of power, time, and the energy consumed in each of the manufacturing processes on production phase showed that LAM utilises more energy than CNC machining. The high energy consumption was as result of duration of production. Energy consumption profiles in CNC machining showed fluctuations with high and low power ranges. LAM energy usage within specific mode (standby, heating, process, sawing) remained relatively constant through the production. CNC machining was limited in terms of manufacturing freedom as it was not possible to manufacture all the designed sample by machining. And the one which was possible was aided with large amount of material removed as waste. Planning phase in LAM was shorter than in CNC machining as the latter required many preparation steps. Specific energy consumption (SEC) were estimated in LAM based on the practical results and assumed platform utilisation. The estimated platform utilisation showed SEC could reduce when more parts were placed in one build than it was in with the empirical results in this thesis (six parts).

Naisjohtajat – miksi heitä ei ole ja mitä siitä? - miesjohtajien ja ei-johtavassa asemassa olevien naisten näkemyksiä case-yritys x:ssä

Joidenkin tutkimusten mukaan naisten vähäinen määrä johdossa voi olla uhka organisaatiolle. Lasikattoilmiöllä tarkoitetaan naisten urakehityksen katkeamista tietylle tasolle ylimmän johdon alapuolelle ikään kuin naisten ja tuon ylimmän tason välissä olisi lasinen, näkymätön katto, sukupuolistereotypioiden muodostama este. Yksi yleinen lasikaton selitysten kolmijako on henkilökohtaiset, organisatoriset ja yhteiskunnalliset tekijät. (Lämsä & Hautala 2004, 252). Hoyt (2007, 270-278) tekee kolmijaon seuraavasti: inhimillinen pääoma, sukupuolierot ja ennakkoluulot. Yritys X:n keskijohdossa työskentelee yksi nainen, ylimmässä johdossa ei yhtäkään. Tutkimuksessa halu-taan selvittää miesjohtajien ja ei-johtavassa asemassa olevien naisten käsitystä siitä, onko yritys x:ssä lasi-kattoa, miksi naisjohtajia on niin vähän ja "mitä siitä" ts. onko mitään ongelmaa olemassakaan. Tässä tutkimuksessa pohditaan diskurssianalyysin keinoin, miten yritys X:ssä puhutaan naisjohtajuusaiheesta, millai-seksi sukupuolen merkitys työelämässä määritellään ja mitä ajatellaan naisten kykenevyydestä johtajiksi. Naturalisoiva diskurssi oli vahva niin miesjohtajien ja ei-johtavassa asemassa olevien naisten puheessa. Sen lisäksi hahmotellaan familistista, empiiristä, humanistista ja historiallista diskurssia naisjohtajuuspuheesta. Diskurssien yhteenkietominen hegemonisoimisstrategiana kuvaa tapaa, jolla palasia muista diskursseista käytetään tukemaan tiettyä toista diskurssia (Jokinen et al. 1993c, 95) Miesjohtajien puheessa naisten keskeiset, ominaisuudet - liiallinen tarkkuus ja huolellisuus yhdistettynä epävarmuuteen - ovat ongelmallisia johtajanuran kannalta. Jos näistä johtajuuden kannalta negatiivisista ominaisuuksista ei jostain syystä kuitenkaan muodostuisi uralla etenemisen estettä, äitiys ja perheellisyys "luonnollisesti" tekee tämän. Aiheet myös kietoutuvat yhteen: äitiys ja vastuu perheestä lisäävät naisten huolellisuutta, tarkkuutta ja epävarmuutta entisestään. Lisäksi äitiyslomat ja työhön käytettävissä oleva aika ja puut-tuva halu käyttää elämästä iso osa uranluomiseen ovat johtajaksi etenemisen esteitä. Miesjohtajien mukaan tämä on jossain määrin ongelma, kun heterogeenisyyttä johtamiseen kuitenkin tarvittaisiin, mutta loppujen lopuksi kuitenkin melko epäkiinnostava ja pieni ongelma; ongelma ei miesten mielestä johdu miesten tai yhteiskunnallisista asenteista, vaan naisista itsestään ja he tarvitsevat uralla edetäkseen tukea, rohkaisua ja henkilöstöpankkeja, joita miesjohtajat voivat tuottaa. Johtaminen ylipäänsä ei ole miesjohtajien mielestä hirveän kiinnostavaa. Jos naiset (kaikesta edellä sanotusta huolimatta) etenevät yritysten johtoon, eivät he tule siellä toimeen keskenään. Kaiken kaikkiaan koko naisjohtajuusaihe ei ole kovin kiinnostava ja naisjohtajuuden vähäisyyden (mahdollisen) ongelman ratkaisee aika uuden, tasa-arvoisemman sukupolven myötä. Naishaastateltujen näkökulmasta sen sijaan naisilla on pyrkyä johtotehtäviin - joskaan ei samassa määrin kuin miehillä. Naishaastateltujen mukaan miehet suosivat toisiaan työelämässä ja naiset kohtaavat asenteita, joita vastaan joutuvat taistelemaan ja tästä syystä johtajien joukossa on niin vähän naisia. Historialliset tekijät pitävät asenteita yllä. Perheellisyys on naisille suurempi uraeste kuin miehille, "luonnollisesti". Naishaastateltujen mielestä naisten vähäisyys johdossa on merkittävä ongelma, koska naisilla on erityislaatuisia ominaisuuksia, joista olisi hyötyä tehtävässä. Naishaastateltujen puheessa miesten ominaisuuksia vastaavasti vähäteltiin. Naisjohtajien vähäisyyden ongelmalle ei naishaastateltujen mielestä kuitenkaan ole tehtävissä paljonkaan: miesten ja yhteiskunnan asenteiden pitäisi muuttua, mutta keinoja tähän ei esitetä, sen sijaan naisten itsensä pitäisi vain "yrittää vielä kovemmin".

Rekrytointimarkkinointi Y-sukupolvelle, miten tavoitamme parhaat osaajat? Case IBM Finland OY

Pro Gradu- tutkimuksen keskeisin tavoite oli selvittää tehokkaimmat rekrytointimarkkinointikanavat ja tyylit Y-sukupolveen kohdistuen. Y-sukupolvi on isoin ja uusin sukupolvi, joka on siirtymässä työelämään. Tällä hetkellä teoreettinen pohja on vielä ohut liittyen y-sukupolven rekrytointiin ja työnantajamielikuvaan ja tämän tutkimuksen oli tarkoitus selvittää tätä tutkimusaukkoa. Tutkimus toteutettiin kvalitatiivisena case-tutkimuksena. Aineistonkeruutapana oli kysely. Kysely toteutettiin sähköpostilla lähetettävällä kyselyllä IBM Suomen nuorille harjoittelijoille ja työntekijöille. Kysely lähetettiin noin 150:lle työntekijälle. Tutkimustulokset osoittivat, että IBM Suomella ovat perusprosessit ja nykyisten harjoittelijoiden tyytyväisyys hyvällä tasolla. Kuitenkin tutkimuskyselyn kautta saatiin selville osa-alueita, joilla rekrytointimarkkinoinnin tehokkuutta voidaan lisätä ja hyväksikäyttää vieläkin paremmin. Tutkimustulosten perusteella Y-sukupolven arvot ja odotukset erosivat muista sukupolvista oletettua vähemmän.

Vancomycin-dependent Enterococcus faecium vanA: characterization of the first case isolated in a university hospital in Brazil

In this study, we report the characterization of a strain of Enterococcus faecium vanA, which grows only in the presence of vancomycin (VDEfm-UEL). The bacterium was isolated from the feces of a female patient who had undergone surgical treatment of Reinke’s edema and was receiving intravenous vancomycin therapy for infection with methicillin/oxacillin-resistant Staphylococcus aureus, a postoperative complication. Antimicrobial dependence was further confirmed by the vancomycin E-test. VDEfm-UEL was also shown to be resistant to ampicillin, ciprofloxacin, chloramphenicol, erythromycin, levofloxacin, penicillin, rifampicin, and teicoplanin. The putative virulence genes efaA, gelE and esp were detected by PCR. The ddl gene from VDEfm-UEL was cloned and sequenced. Vancomycin dependence seems to be associated with the insertion of a nucleotide in that sequence, which results in a frame-shift mutation, introducing a premature stop codon. This is the first report of vancomycin-dependent E. faecium isolation in a university hospital in Brazil.

Amniotic fluid amino acid levels in non-immune hydrops fetalis: a case-control study

In a prospective case-control study, we compared the amniotic fluid amino acid levels in non-immune hydrops fetalis (NIHF) and normal fetuses. Eighty fetuses underwent amniocentesis for different reasons at the prenatal diagnosis unit of the Department of Obstetrics and Gynecology, Faculty of Medicine, Dicle University. Forty of these fetuses were diagnosed with NIHF. The study included 40 women each in the NIHF (mean age: 27.69 ± 4.56 years) and control (27.52 ± 5.49 years) groups, who had abnormal double- or triple-screening test values with normal fetuses with gestational ages of 23.26 ± 1.98 and 23.68 ± 1.49 weeks at the time of sample collection, respectively. Amniotic fluid amino acid concentrations (intra-assay variation: 2.26-7.85%; interassay variation: 3.45-8.22%) were measured using EZ:faast kits (EZ:faast GC/FID free (physiological) amino acid kit; Phenomenex, USA) by gas chromatography. The standard for quantitation was a mixture of free amino acids from Phenomenex. The levels of 21 amino acids were measured. The mean phosphoserine and serine levels were significantly lower in the NIHF group, while the taurine, α-aminoadipic acid (aaa), glycine, cysteine, NH4, and arginine (Arg) levels were significantly higher compared to control. Significant risk variables for the NIHF group and odds coefficients were obtained using a binary logistic regression method. The respective odds ratios and 95% confidence intervals for the risk variables phosphoserine, taurine, aaa, Arg, and NH4 were 3.31 (1.84-5.97), 2.45 (1.56-3.86), 1.78 (1.18-2.68), 2.18 (1.56-3.04), and 2.41 (1.66-3.49), respectively. The significant difference between NIHF and control fetuses suggests that the amniotic fluid levels of some amino acids may be useful for the diagnosis of NIHF.

Integration of marketing research data in new product development. Case study: Food industry company

The aim of this master’s thesis is to provide a real life example of how marketing research data is used by different functions in the NPD process. In order to achieve this goal, a case study in a company was implemented where gathering, analysis, distribution and synthesis of marketing research data in NPD were studied. The main research question was formulated as follows: How is marketing research data integrated and used by different company functions in the NPD process? The theory part of the master’s thesis was focused on the discussion of the marketing function role in NPD, use of marketing research particularly in the food industry, as well as issues related to the marketing/R&D interface during the NPD process. The empirical part of the master’s thesis was based on qualitative explanatory case study research. Individual in-depth interviews with company representatives, company documents and online research were used for data collection and analyzed through triangulation method. The empirical findings advocate that the most important marketing data sources at the concept generation stage of NPD are: global trends monitoring, retailing audit and consumers insights. These data sets are crucial for establishing the potential of the product on the market and defining the desired features for the new product to be developed. The findings also suggest the example of successful crossfunctional communication during the NPD process with formal and informal communication patterns. General managerial recommendations are given on the integration in NPD of a strategy, process, continuous improvement, and motivated cross-functional product development teams.

Reorganising purchasing organisation – Case Metsä Wood

The purpose of this study is to investigate how a global company should organise its purchasing operations. The theoretical framework of this study consists of organisation structures, management and coordination, purchasing organisational design, capabilities and outsourcing. The research is a qualitative case study and the used method was theme interview. Four global large scale companies were interviewed for this research in order to gain knowledge about how other companies have organised their purchasing functions and to gather their best practices. Interview results and theoretical framework were compared in order to test the theoretical framework and to create a detailed framework about how to organise purchasing operations in a global company. As a result a 14 point model about effective purchasing operation organisation for a global company was created. This model includes all the key determinants which should be considered when organising the purchasing operations. The results show that the organising decision should be always in line with company and purchasing strategies. Strategic purchasing operations should be centralized and operative tasks decentralized.

Dynamics AX -toiminnanohjausjärjestelmän jatkuvuudenhallinta ja toipumissuunnitelma - Simulaatiotestausmalli: case CGI Suomi Oy

Nyky-yhteiskunta nojautuu vahvasti tietojärjestelmiin luoden laajemman arkkitehtuurisen kokonaisuuden, kybertoimintaympäristön. Liiketoimintaa tukevat tietojärjestelmät tukevat myös organisaatioiden prosesseja kokonaisvaltaisesti. Jotta näitä tärkeitä kyberympäristön tietojärjestelmä- sekä liiketoimintaympäristöresursseja pystytään käyttämään, tulee järjestelmien olla luotettavia ja sovellusten saatavilla vuorokauden ympäri tai aina tarvittaessa. Tilanteet, joissa järjestelmän käytettävyys vaarantuu, voivat eskaloitua yllättäen suuremmiksi, jos poikkeustilanteisiin ei ole varauduttu. Poikkeustilanteisiin varautumiseen tarvitaan jatkuvuudenhallintaa, joka on kiinteästi osa kattavampaa IT-strategiaa ja koko yhteiskunta-/yrityskulttuuria. Työ on toteutettu yhdistäen empiriaa ja teoriaa eli tavoitteena on teoreettisen tietämyksen ja käytännön kokemuksellisen oppimisen ja tietämyksen kautta luoda konstruktiivisella otteella toipumissuunnitelman testauksessa käytettävä simulaatiotestausmalli. Dynamics AX -toiminnanohjausjärjestelmän toipumissuunnitelman simulaatiotestausmallista rakentui selkeä ja kevyt työkalu asiakasyritysten toipumissuunnitelman simulaatiotestauksiin. Diplomityössä kuvatuilla keinotekoisilla järjestelmän häiriötilanteilla pystytään simuloimaan Dynamics AX:n toipumissuunnitelman testauksissa oikeita häiriötilanteita suhteellisen kattavalla tasolla.

Forsaking all others: towards a new model of nationalism utilizing the case study of former Yugoslavia

Many people would like to believe that nationalism is a thing of the past, a dinosaur belonging to some bygone, uncivilized era. Such a belief is not borne out by recent history, however. Nationalism occupies the political forum with as much force as ever. Yet, in many ways, it remains a mystery to us. The purpose of this study is to explore individual motivations involved in the rise of nationalism, in addition to the role of structural factors. The linkage employed in this exploration is the psychosocial phenomenon of self-identity, including emotions and self-esteem. We demonstrate how individual, socially-constructed self-identity accounts for why some people embrace nationalism while others eschew it. The methodology employed was theoretical and historical analyses of secondary sources and indepth interviews with subjects who had some connection with former Yugoslavia, the country utilized to test the new model. Our analyses yielded the result that current conceptualizations of nationalism from an exclusively macro or micro perspective are unsatisfactory; we require a more comprehensive approach wherein the two perspectives are integrated. Such an integration necessitates a bridge: hence, our new model, which rests on the psychosocial premise, offers a more useful conceptual tool for the understanding of nationalism. We conclude that nationalism is first and foremost a matter relating to individual social self-identity which takes place within a particular context where oppositional forces emerge from structural factors and our membership in a particular group becomes paramount.

Posttraumatic stress disorder symptoms might be destroying your intimacy : a test of mediational models in a community sample of couples

The present research focused on the pathways through which the symptoms of posttraumatic stress disorder (PTSD) may negatively impact intimacy. Previous research has confirmed a link between self-reported PTSD symptoms and intimacy; however, a thorough examination of mediating paths, partner effects, and secondary traumatization has not yet been realized. With a sample of 297 heterosexual couples, intraindividual and dyadic models were developed to explain the relationships between PTSD symptoms and intimacy in the context of interdependence theory, attachment theory, and models of selfpreservation (e.g., fight-or-flight). The current study replicated the findings of others and has supported a process in which affective (alexithymia, negative affect, positive affect) and communication (demand-withdraw behaviour, self-concealment, and constructive communication) pathways mediate the intraindividual and dyadic relationships between PTSD symptoms and intimacy. Moreover, it also found that the PTSD symptoms of each partner were significantly related; however, this was only the case for those dyads in which the partners had disclosed most everything about their traumatic experiences. As such, secondary traumatization was supported. Finally, although the overall pattern of results suggest a total negative effect of PTSD symptoms on intimacy, a sex difference was evident such that the direct effect of the woman's PTSD symptoms were positively associated with both her and her partner's intimacy. I t is possible that the Tend-andBefriend model of threat response, wherein women are said to foster social bonds in the face of distress, may account for this sex difference. Overall, however, it is clear that PTSD symptoms were negatively associated with relationship quality and attention to this impact in the development of diagnostic criteria and treatment protocols is necessary.

Imagerie à haut contraste et caractérisation d'exoplanètes par la spectroscopie intégrale de champ

Cette thèse porte sur l’amélioration des techniques d’imagerie à haut-contraste permettant la détection directe de compagnons à de faibles séparations de leur étoile hôte. Plus précisément, elle s’inscrit dans le développement du Gemini Planet Imager (GPI) qui est un instrument de deuxième génération pour les télescopes Gemini. Cette caméra utilisera un spectromètre à champ intégral (SCI) pour caractériser les compagnons détectés et pour réduire le bruit de tavelure limitant leur détection et corrigera la turbulence atmosphérique à un niveau encore jamais atteint en utilisant deux miroirs déformables dans son système d’optique adaptative (OA) : le woofer et le tweeter. Le woofer corrigera les aberrations de basses fréquences spatiales et de grandes amplitudes alors que le tweeter compensera les aberrations de plus hautes fréquences ayant une plus faible amplitude. Dans un premier temps, les performances pouvant être atteintes à l’aide des SCIs présentement en fonction sur les télescopes de 8-10 m sont investiguées en observant le compagnon de l’étoile GQ Lup à l’aide du SCI NIFS et du système OA ALTAIR installés sur le télescope Gemini Nord. La technique de l’imagerie différentielle angulaire (IDA) est utilisée pour atténuer le bruit de tavelure d’un facteur 2 à 6. Les spectres obtenus en bandes JHK ont été utilisés pour contraindre la masse du compagnon par comparaison avec les prédictions des modèles atmosphériques et évolutifs à 8−60 MJup, où MJup représente la masse de Jupiter. Ainsi, il est déterminé qu’il s’agit plus probablement d’une naine brune que d’une planète. Comme les SCIs présentement en fonction sont des caméras polyvalentes pouvant être utilisées pour plusieurs domaines de l’astrophysique, leur conception n’a pas été optimisée pour l’imagerie à haut-contraste. Ainsi, la deuxième étape de cette thèse a consisté à concevoir et tester en laboratoire un prototype de SCI optimisé pour cette tâche. Quatre algorithmes de suppression du bruit de tavelure ont été testés sur les données obtenues : la simple différence, la double différence, la déconvolution spectrale ainsi qu’un nouvel algorithme développé au sein de cette thèse baptisé l’algorithme des spectres jumeaux. Nous trouvons que l’algorithme des spectres jumeaux est le plus performant pour les deux types de compagnons testés : les compagnons méthaniques et non-méthaniques. Le rapport signal-sur-bruit de la détection a été amélioré d’un facteur allant jusqu’à 14 pour un compagnon méthanique et d’un facteur 2 pour un compagnon non-méthanique. Dernièrement, nous nous intéressons à certains problèmes liés à la séparation de la commande entre deux miroirs déformables dans le système OA de GPI. Nous présentons tout d’abord une méthode utilisant des calculs analytiques et des simulations Monte Carlo pour déterminer les paramètres clés du woofer tels que son diamètre, son nombre d’éléments actifs et leur course qui ont ensuite eu des répercussions sur le design général de l’instrument. Ensuite, le système étudié utilisant un reconstructeur de Fourier, nous proposons de séparer la commande entre les deux miroirs dans l’espace de Fourier et de limiter les modes transférés au woofer à ceux qu’il peut précisément reproduire. Dans le contexte de GPI, ceci permet de remplacer deux matrices de 1600×69 éléments nécessaires pour une séparation “classique” de la commande par une seule de 45×69 composantes et ainsi d’utiliser un processeur prêt à être utilisé plutôt qu’une architecture informatique plus complexe.