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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Augmentation des performances des systèmes DSL par allocation dynamique de spectre

Tlich, Mohamed 23 June 2006 (has links) (PDF)
Les systèmes DSL sont des technologies de transmission qui transportent des flux de données importants sur de simples lignes téléphoniques. Malheureusement, plusieurs phénomènes perturbateurs sont susceptibles de dégrader la qualité des liaisons. Les limitations sont principalement dues à l'affaiblissement ainsi qu'à des problèmes de compatibilité électromagnétique. Dans ce contexte, ce travail de thèse consiste à augmenter les performances marge de bruit/débit/portée des systèmes DSL par allocation dynamique de spectre (DSM: Dynamic Spectrum Management). Dans une première partie sont développées trois méthodes d'allocation discrète de bits entre les porteuses d'un système DSL à modulation DMT. La première est une simplification importante de l'algorithme de P.S. Chow à distribution plate d'énergie. La deuxième étant un processus de moindre complexité qui nous ramène à la distribution optimale d'énergie entre les porteuses, appelé "remplissage par Gammas croissants". Et la troisième est une méthode d'attribution de marges de bruit distinctes aux différents flux d'une même liaison DSL. Après cette amélioration de la technologie de transmission DSL qui constitue le niveau 0 de la DSM, l'atténuation de l'interférence entre les lignes d'un même câble DSL par allocation coordonnée de spectre (niveau 2 de la DSM) est abordée, et deux procédés sont proposés. Le premier est un procédé de réglage dynamique des DSP des porteuses les unes indépendamment des autres, de façon à réduire l'interférence provenant de certaines lignes dont le débit est supérieur au débit nécessaire aux services. Le deuxième procédé est une nouvelle architecture DSL, caractérisée par l'introduction d'éléments actifs dans la sous-répartition. Les performances des lignes, divisées en deux tronçons plus courts et séparés, sont ainsi améliorées. Dans une dernière partie est considérée la transmission vectorielle qui constitue le troisième niveau de la DSM. Des méthodes d'annulation d'interférence entre les lignes d'un même câble DSL sont présentées, et un modèle de détermination de la matrice de canal MIMO est développé.
32

Etude de la rhéologie des loess du Nord de la France - Application à l'évaluation de leur risque de liquéfaction

Karam, Jean-Paul 23 November 2006 (has links) (PDF)
Pour mieux comprendre les problèmes de stabilité observés sur la ligne nord du TGV en Picardie, des essais de caractérisation mécanique ont été réalisés sur le loess naturel qui est le sol de la fondation ferroviaire. L'accent a été mis sur son comportement sous un grand nombre de chargements cycliques dans des conditions non saturées, sur son comportement d'effondrement à l'humidification et sur sa susceptibilité de liquéfaction quand la saturation est atteinte. Les résultats obtenus ont montré que la couche située à 2,20m présente le plus grand risque d'instabilité. Une nouvelle méthode évaluation des risques de liquéfaction a été développée à partir d'essais courants de géotechniques. Cette méthode prend en compte notamment l'effet de la non saturation initiale. Une application directe de cette méthode sur 4 sites différents a monté une cohérence avec les sondages in situ. Sur le plan numérique, un modèle élastoplastique avec endommagement a été développé pour décrire les principaux phénomènes observés tels que l'effondrement dû à la diminution de la succion, l'endommagement et la liquéfaction dus au chargement cyclique.
33

Undersökning av modulationsscheman för existerande bredbandsteknologier / A Study of Modulation Schemes for Existing Broadband Technologies

Lundström, Petra January 2005 (has links)
<p>In this thesis some different modulation schemes for xDSL-techniques are compared. The investigated techniques are ADSL, G.lite, ADSL2, HDSL, SHDSL and VDSL. The modulation methods used are DMT, CAP and different versions of PAM. Several broadband techniques also use Trellis Coded Modulation (TCM) to increase the coding gain of the transmission. For each one of the different modulation methods the signal-to-noise ratio is calculated for generating a bit error rate probability of 10-7. This is the error rate that is demanded for several of the investigated standards. Comparison is also made of the transmission capacity of the channel and how sensitive the technique is for interference in a part of the frequency band. To compare the different modulation techniques, simulations of the modulations were made. The simulations were made with MatLab and Simulink. Unfortunately Simulink only supports one- and two-dimensional TCM. Therefore no good simulations of ADSL and ADSL2 with TCM were made, because those techniques use four-dimensional TCM.</p>
34

Transsexualism and personality : methodological and clinical studies on gender identity disorders

Bodlund, Owe January 1994 (has links)
Patients suffering from transsexualism (TS) who apply for sex reassignment surgery (SRS) go through a complex evaluation process before being accepted for treatment. In general, the results from SRS are satisfying. However, further knowledge is needed to clearly delineate transsexualism from other related gender identity disorders (GID) and to improve the selection of candidates for SRS. Personality has for a long time been considered as the key concept for that purpose but systematic studies using reliable instruments are lacking. The present study aims at improving the assessment procedure, validating the concept of transsexualism and studying the outcome of SRS and important prognostic factors. Two methodological studies deal with the development and validation of two self-report instruments based on DSM-III-R: SCID screen covering Axis II personality disorders/traits and Global Assessment of Functioning (GAF-scale, Axis V). SCID screen diagnoses of personality disorders (PD) were compared with diagnoses from independent structured interviews by means of the SCID-II. The overall kappa in identifying a PD was 0.78 varying from 0.34 to 0.81 for the specific PDs when cut-off was adjusted. When applied to a group of GID-patients SCID screen diagnoses agreed well with clinical diagnoses (kappa 0.77). Self-report of the GAF also proved to be a reliable (overall Pearson r=0.62) and useful method and the study lends further support to the validity of Axis V. In three papers a group of 19 transsexuals was studied by means of a) SCID screen to examine their personality in a dimensional and traditional categorical way, b) the GAF-scale to study psychosocial functioning, c) Structural Analysis of Social Behavior (SASB) to examine self-image and d) Defense Mechanism Test (DMT) to analyze psychological defense structures from a psychodynamic perspective. Patients with atypical gender identity disorders (GIDAANT) and patients with borderline personality disorders as well as healthy subjects were used as contrast groups. Among the transsexuals 10 out of 19 had an additional axis I disorder and 37% had at least one PD, predominantly within cluster B. When analyzed dimensionally according to SCID screen, frequent subthreshold personality pathology was found and biological women fulfilled more axis II criteria than men. TS had less axis I and II pathology compared with GIDAANT and psychiatric patients. According to SASB, TS had a positive self-image with both self-control and spontaneous self and predominating self-love. They appeared significantly more healthy on self-image measures than GIDAANT patients. The DMT revealed a different pattern; TS patients were more disturbed in several areas than patients with borderline personality disorder. TS showed no ”emotional investment” and poorer reality orientation in contrast to both healthy controls and the borderline group but shared a similar pregenital pathology with the borderline patients. Finally, five-year outcome was studied among the transsexuals from a multidimensional approach (e.g. work, interpersonal relations, partnership, subjective opinion) and related to index- measurements on DSM-III-R, SCID screen, GAF, SASB and DMT. Based on combined outcome variables, 68% of the subjects were judged to have improved and 16% had an unsatisfactory outcome. One single case regretted the sex change. SCID screen pathology and SASB disturbances emerged as significant predictors for negative outcome, as well as male biological sex and lack of partnership. It was concluded, that although outcome is in general very favorable, the instruments under investigation, in particular SCID screen and SASB, revealed valuable prognostic information and they are suggested to become part of the future routine assessment of candidates for SRS. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1995, härtill 6 uppsatser.</p> / digitalisering@umu
35

Interpretação de ensaios DMT em solos com drenagem parcial

Belloli, Marcus Vinicius Alves January 2018 (has links)
Entre os objetivos da engenharia geotécnica está a busca pelo entendimento e previsão do comportamento mecânico dos solos. Para isso, existem basicamente duas abordagens: ensaios de laboratório ou ensaios de campo. Em cada obra o Engenheiro Geotécnico deve julgar quais são os métodos e procedimentos mais indicados de investigação, que resultarão em parâmetros confiáveis de projeto. Os ensaios de campo foram desenvolvidos baseados nos solos argilosos e arenosos em virtude dos comportamentos distintamente bem definidos, especialmente em termos de drenagem. O mesmo ocorre para o ensaio DMT, cuja execução e interpretação são influenciadas pelo tipo de solo e pelas condições de drenagem. O grande desafio, neste caso, está na interpretação dos ensaios em solos cuja solicitação ocorre sob condição de drenagem parcial, como nos casos de barragens de rejeito de mineração, ou em depósitos naturais de solos siltosos, onde esta condição pode levar a erros de interpretação. No DMT, a ocorrência de drenagem parcial influencia tanto na etapa de cravação da lâmina, quanto na etapa de expansão da membrana. Neste sentido, o foco deste trabalho está no problema da dissipação de poropressão durante a expansão da membrana, apresentando procedimentos especiais para realização do ensaio DMT. Serão apresentados dois métodos de interpretação de resultados, visando compensar os erros de interpretação causados pela dissipação parcial de poropressão: Método de Dissipação Completa e, Método de Dissipação Incompleta. Este trabalho foi desenvolvido baseado na realização de ensaios de campo, com uma campanha executada em solo brasileiro argiloso, que serviu de base à interpretação, sendo complementada por 6 ensaios realizados em diferentes sítios na Itália. Os resultados dos ensaios realizados pelo Método de Dissipação Completa foram interpretados através de duas abordagens: Método da Igualdade (analítico) e Método Simplificado. Enquanto a interpretação do Método de Dissipação Incompleta é permitida apenas através de procedimento simplificado. A análise paramétrica apresentou comportamentos similares entre ambas abordagens, demonstrando que a taxa de dissipação é o fator que mais influencia nos resultados. Ao final, os métodos foram aplicados e validados em diferentes locais, apresentando resultados adequados e compatíveis com o comportamento previamente definido através de outros ensaios. / Among the geotechnical engineering goals are the understanding and prediction of soil behavior. For this, there are basically two approaches: laboratory or in situ tests. In this case, the Geotechnical Engineer must judge the most appropriate investigation methods and procedures that will result in reliable design parameters. In situ tests were developed for clay and sand given to the fact that the behavior of these soils is well-defined and drainage conditions are properly controlled. The DMT is no exception, with test and interpretation methods influenced by the drainage conditions. The challenge resides in the interpretation of tests carried out in soils under partial-drainage conditions, such as tailings dams or natural deposits of silty soils, where partial-drainage conditions are taking place around the DMT blade leading to errors on its interpretation. The partial drainage condition influences both the DMT blade penetration phase and the membrane expansion phase. In this sense, this work focus on the problem of the pore pressure dissipation taking place simultaneously to membrane expansion. A non-standard procedure is proposed to sounding the DMT in silts that include two methods for DMT interpretation in order to compensate the errors caused by the partial pore pressure dissipation: Method of Complete Dissipation Curve and Method of Incomplete Dissipation Curve. This work was developed based on tests carried out in Brazilian clay soils to develop the proposed approach that was validated latter in non-standard tests carried out in different Italian sites. The results of the tests performed by the complete dissipation method were interpreted through two approaches: Equality Method (analytical) and Simplified Method, while the interpretation of the incomplete dissipation method is possible only through simplified procedure. The parametric analysis showed that these approaches yield similar results, demonstrating that the dissipation rate is the most important factor in the analysis. At the end, the methods were applied and validated at different sites, showing results that are compatible to previously defined behavior of the soils.
36

Interpretação de ensaios DMT em solos com drenagem parcial

Belloli, Marcus Vinicius Alves January 2018 (has links)
Entre os objetivos da engenharia geotécnica está a busca pelo entendimento e previsão do comportamento mecânico dos solos. Para isso, existem basicamente duas abordagens: ensaios de laboratório ou ensaios de campo. Em cada obra o Engenheiro Geotécnico deve julgar quais são os métodos e procedimentos mais indicados de investigação, que resultarão em parâmetros confiáveis de projeto. Os ensaios de campo foram desenvolvidos baseados nos solos argilosos e arenosos em virtude dos comportamentos distintamente bem definidos, especialmente em termos de drenagem. O mesmo ocorre para o ensaio DMT, cuja execução e interpretação são influenciadas pelo tipo de solo e pelas condições de drenagem. O grande desafio, neste caso, está na interpretação dos ensaios em solos cuja solicitação ocorre sob condição de drenagem parcial, como nos casos de barragens de rejeito de mineração, ou em depósitos naturais de solos siltosos, onde esta condição pode levar a erros de interpretação. No DMT, a ocorrência de drenagem parcial influencia tanto na etapa de cravação da lâmina, quanto na etapa de expansão da membrana. Neste sentido, o foco deste trabalho está no problema da dissipação de poropressão durante a expansão da membrana, apresentando procedimentos especiais para realização do ensaio DMT. Serão apresentados dois métodos de interpretação de resultados, visando compensar os erros de interpretação causados pela dissipação parcial de poropressão: Método de Dissipação Completa e, Método de Dissipação Incompleta. Este trabalho foi desenvolvido baseado na realização de ensaios de campo, com uma campanha executada em solo brasileiro argiloso, que serviu de base à interpretação, sendo complementada por 6 ensaios realizados em diferentes sítios na Itália. Os resultados dos ensaios realizados pelo Método de Dissipação Completa foram interpretados através de duas abordagens: Método da Igualdade (analítico) e Método Simplificado. Enquanto a interpretação do Método de Dissipação Incompleta é permitida apenas através de procedimento simplificado. A análise paramétrica apresentou comportamentos similares entre ambas abordagens, demonstrando que a taxa de dissipação é o fator que mais influencia nos resultados. Ao final, os métodos foram aplicados e validados em diferentes locais, apresentando resultados adequados e compatíveis com o comportamento previamente definido através de outros ensaios. / Among the geotechnical engineering goals are the understanding and prediction of soil behavior. For this, there are basically two approaches: laboratory or in situ tests. In this case, the Geotechnical Engineer must judge the most appropriate investigation methods and procedures that will result in reliable design parameters. In situ tests were developed for clay and sand given to the fact that the behavior of these soils is well-defined and drainage conditions are properly controlled. The DMT is no exception, with test and interpretation methods influenced by the drainage conditions. The challenge resides in the interpretation of tests carried out in soils under partial-drainage conditions, such as tailings dams or natural deposits of silty soils, where partial-drainage conditions are taking place around the DMT blade leading to errors on its interpretation. The partial drainage condition influences both the DMT blade penetration phase and the membrane expansion phase. In this sense, this work focus on the problem of the pore pressure dissipation taking place simultaneously to membrane expansion. A non-standard procedure is proposed to sounding the DMT in silts that include two methods for DMT interpretation in order to compensate the errors caused by the partial pore pressure dissipation: Method of Complete Dissipation Curve and Method of Incomplete Dissipation Curve. This work was developed based on tests carried out in Brazilian clay soils to develop the proposed approach that was validated latter in non-standard tests carried out in different Italian sites. The results of the tests performed by the complete dissipation method were interpreted through two approaches: Equality Method (analytical) and Simplified Method, while the interpretation of the incomplete dissipation method is possible only through simplified procedure. The parametric analysis showed that these approaches yield similar results, demonstrating that the dissipation rate is the most important factor in the analysis. At the end, the methods were applied and validated at different sites, showing results that are compatible to previously defined behavior of the soils.
37

Zpracování a vyhodnocení mapových podkladů v prostředí GIS pro povodí toku Ostřice. / Elaboration and interpretation of map materials in GIS for the Ostrice stream catchment.

HOUDEK, Jiří January 2009 (has links)
The aim of the thesis was the creation and interpretation of thematic layers for the Ostřice stream catchment. First step was collecting all the available maps and comparing them with the actual state. The documents were digitized, and the thematic layers were created. The map outputs were created from these layers and their combinations and were analyzed. The output of this work is a set of GIS layers for the Ostřice stream catchment. This work was processed with the ArcGIS Desktop 9.1 software.
38

Undersökning av modulationsscheman för existerande bredbandsteknologier / A Study of Modulation Schemes for Existing Broadband Technologies

Lundström, Petra January 2005 (has links)
In this thesis some different modulation schemes for xDSL-techniques are compared. The investigated techniques are ADSL, G.lite, ADSL2, HDSL, SHDSL and VDSL. The modulation methods used are DMT, CAP and different versions of PAM. Several broadband techniques also use Trellis Coded Modulation (TCM) to increase the coding gain of the transmission. For each one of the different modulation methods the signal-to-noise ratio is calculated for generating a bit error rate probability of 10-7. This is the error rate that is demanded for several of the investigated standards. Comparison is also made of the transmission capacity of the channel and how sensitive the technique is for interference in a part of the frequency band. To compare the different modulation techniques, simulations of the modulations were made. The simulations were made with MatLab and Simulink. Unfortunately Simulink only supports one- and two-dimensional TCM. Therefore no good simulations of ADSL and ADSL2 with TCM were made, because those techniques use four-dimensional TCM.
39

Využití programových prostředků GIS a CAD pro tvorbu digitálního modelu terénu / Usage of GIS and CAD software for Digital Terrain Model

Čička, Peter January 2014 (has links)
Master thesis is focused on formation of digital terrain model. The aim of work is to become acquainted with a dilemma in regard to terrain formation theory from the very beginning of data gathering process up to landscape digital model creation of interested area. The result of thesis is to compare advantages and disadvantages of particular programs destined for 3D modelling (ArcGIS, AutoCAD, Atlas DMT, Microstation, Catia, SolidWorks) in relation to geodetics and geoinformatics.
40

Vícetónová modulace realizovaná bankou filtrů / Multitone Modulation Implemented via Filter Bank

Krajsa, Ondřej January 2011 (has links)
The work is focused on multitone modulation implemented by filter banks, which are alternative modulations to DMT and OFDM modulations. The paper describes the two proposed modulation schemes, non-overlapped FMT and half-overlapped FMT. This modulations utilize the benefits of implementing FFT algorithm in conjunction with a bank of polyphase filters that are derived from the prototype filter. To design the prototype filter a Matlab tool is developed. For both modulations the simulation models were created for xDSL systems and for wireless transmission channel. Non-overlapped FMT modulation proved to be a suitable modulation scheme for channels with narrowband interference and sharp edges in the transmission function of the channel. It was allowed by perfect separation of each subchannel and with preserving the orthogonality between subchannels using the FFT algorithm and utilization of appropriate filters. Half-overlapped FMT modulation allows as well as the DMT modulation optimal utilization of provided transmittion band, because the power spectral density of the signal is flat. But it is not suitable for transmission channels with roughly shaped by changes in the transmission function and narrowband interference. Optimization implementations were designed using parallel processing on the DSP Texas Instruments TMS320C67x series. It thus achieved almost ten-fold reduction in computational complexity. In FMT modulation both options ensure increased signal to noise ratio and thus allow the use of constellation diagrams with a large number of signal elements with the same transmit power and also higher transmission speed.

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