Zugl.: Münster (Westfalen), Univ., Habil.-Schr., 2003/2004

Zugl.: Erfurt, Univ., Diss., 2003

Zugl.: Freiburg (Breisgau), Universiẗat, Diss., 2008.

Thesis--Catholic University of America, 1978. / Includes bibliographical references (p. [167]-170). Also issued online.

Διανύουμε μια εποχή, όπου οι ανάγκες για μετάδοση πληροφορίας αυξάνονται ταχύτατα, με αποτέλεσμα τα χάλκινα καλώδια να μην αρκούν για να μεταδώσουν το πλήθος αυτό της πληροφορίας. Έτσι, περάσαμε στις Οπτικές Τηλεπικοινωνίες, όπου τα χάλκινα καλώδια αντικαταστάθηκαν από οπτικές ίνες και φορείς μετάδοσης της πληροφορίας δεν είναι πλέον τα ηλεκτρόνια αλλά τα φωτόνια. Κατά τη μετάδοση της πληροφορίας υπάρχουν όμως, φαινόμενα εξασθένησης και παραμόρφωσης του σήματος. Τη λύση σε αυτά τα προβλήματα καλείται να δώσει η χρήση σολιτονίων. Στην παρούσα διπλωματική εργασία, θα μελετήσουμε τον τρόπο με τον οποίον επηρεάζουν τα φαινόμενα ανώτερης τάξης την αλληλεπίδραση δύο γειτονικών σολιτονιακών παλμών που διαδίδονται μέσα σε μία οπτική ίνα. Πιο συγκεκριμένα, με τη χρήση αλγόριθμου της Fortran θεωρήσαμε δύο θεμελιώδεις σολιτονιακούς παλμούς και μελετήσαμε πως επηρεάζεται η διάδοσή τους κατά μήκος μιας οπτικής ίνας, αλλά και η μεταξύ τους αλληλεπίδρασή, από τη μεταξύ τους απόσταση, το σχετικό τους πλάτος καθώς και από τη διαφορά φάσης. Επιπλέον περιορίζοντας τη μεταξύ τους αλληλεπίδραση μελετήσαμε το πώς επηρεάζουν τη διάδοσή τους φαινόμενα ανώτερης τάξης όπως η σκέδαση Raman, η αυτό-διαμόρφωση απότομων άκρων (self-steepening) και η διασπορά τρίτης τάξης. / We are in an era where the need to transmit information rapidly increases, making the copper wires not enough to convey the multitude of this information. Thus, we moved on Optical Communications, where the copper cables were replaced by optical fibers and broadcasters of information are no longer electrons but photons. During the transmission of information we come across with problems such as attenuation and signal distortion. The use of solitons has come to give the solution to these problems. In this paper, we studied how the higher order phenomena, affects the interaction of two neighboring soliton pulses propagating through an optical fiber. More specifically, using a Fortran algorithm considering two fundamental soliton pulses we have studied how the propagation and their interaction is affected by their relative amplitude and phase difference. Also limiting the interaction between them, we have studied how the propagation is affected by higher order phenomena such as Stimulated Raman Scattering, Self Steepening and third order dispersion.

La tomographie optique diffuse (TOD) est une méthode d'imagerie médicale émergente permettant de faire l'acquisition des coefficients d'absorption et de diffusion, de même que la détection d'inclusions fluorescentes ou bioluminescentes à l'intérieur d'un sujet. Ce type d'imagerie vise de nombreuses applications, dont la mammographie optique, l'imagerie cérébrale fonctionnelle et l'imagerie sur petits animaux pour la recherche préclinique. La TOD utilise la lumière laser rouge et proche infrarouge pour illuminer le sujet à l'étude. Les photons diffus ressortant du sujet sont ensuite captés par des détecteurs tout autour de l'animal. L'acquisition de données en TOD peut être réalisée dans trois régimes d'opération, soit le régime continu, les mesures dans le domaine fréquentiel et les mesures dans le domaine temporel. Ce dernier régime permet l'obtention d'information beaucoup plus riche que les autres régimes, et est donc le sujet d'intérêt du présent mémoire. Depuis plusieurs années, le laboratoire TomOptUS développe l'instrumentation nécessaire aux systèmes de TOD à mesures dans le domaine temporel (TOD-DT) pour l'imagerie moléculaire in vivo sur petits animaux. Des travaux récents ont mené à la réalisation d'un scanner TOD-DT sans contact et à angles de vue multiples, de même qu'au développement des algorithmes de reconstruction d'image. Le scanner actuel ne permet toutefois pas l'imagerie de sujets vivants, le temps d'acquisition étant trop long pour garder un animal sous anesthésie. Pour améliorer significativement la sensibilité, le nombre de canaux de détection autour du sujet doit être augmenté afin d'éviter le balayage mécanique de multiples positions de détecteurs. Le système actuel a toutefois atteint son plein potentiel, ses possibilités d'expansion étant limitées par le système d'acquisition de données. Les travaux de recherche du présent mémoire portent sur la conception de l'électronique d'un système d'acquisition spécialement conçu pour la TOD-DT et pour l'intégration d'un plus grand nombre de canaux (64 et plus) dans l'anneau de détection. Ce système propose une architecture à canaux multiples extensible permettant de combiner plusieurs canaux dans un seul système d'acquisition. Son système électronique modulaire à carte mère et cartes filles supporte tous les types de détecteurs monophotoniques sur le marché et s'adapte à tout type de signal. Le système d'acquisition offre aussi un procédé de calibration entièrement programmable permettant d'éviter l'ajustement manuel des longueurs de câble lors de l'assemblage du système. Comme le système utilise uniquement des composants électroniques disponibles sur le marché, le coût par canal est réduit de plus d'un ordre de grandeur, passant de > 10 000 CAD pour un système conventionnel à < 750 CAD pour le système dédié. Ce dernier offre des performances très compétitives par rapport aux systèmes d'acquisition commerciaux, avec une taille de bin de 13,02 ps, une précision moyenne de 19 ps largeur à la mi-hauteur (LMH) et une non-linéarité intégrale maximale de 10% LSB.

Stationsnäraprincipen innebär att stadsutveckling koncentreras kring knutpunkter i kollektivtrafiken för att öka tillgängligheten och kollektivtrafikens konkurrenskraft mot bilburna transporter för att stärka en hållbar regionförstoring. Visionen att planera stationsnära i Östergötland kommer från regional nivå och för att implementera visionen i den kommunala planeringen blir det viktigt att visa hur både regionen och varje enskild kommun kan gynnas. Ett tillvägagångssätt är att hitta en arbetsmodell som kan lyfta regionala perspektiv i den lokala planeringsprocessen. Syftet med det här arbetet är att ta fram en förtätningsmodell för stationsnära planering i mindre tätorter. En förtätningsmodell för stockholmsregionen har tidigare tagits fram i samband med den regionala utvecklingsplanen och i det här arbetet undersöks om den modellen kan anpassas för stationsnära planering i mindre tätorter. Förtätningsmodellen har metodiskt anpassats med hjälp från två planerare i Östergötland samt en litteraturstudie om regional utveckling och stationsnära planering. Den anpassade modellen har prövats i två separata fallstudier och resultatet omfattar en kartläggning av förtätningspotentialen som beskrivs utifrån tre olika förtätningsscenarion; kommunala fokusområden för stationsnära planering, marknadsintressanta exploateringsområden och konsensusutveckling. Modellen möjliggör att den regionala visionen för stationsnära planering förs in i den kommunala planeringsprocessen och visar inte enbart hur både kommun och region kan gynnas av ett samarbete, utan även vilka knäckfrågor den enskilda kommunen måste övervinna för att fortsätta utvecklas i framtiden. / Stationsnäraprincipen imply that urban development is concentrated around public transport nodes to increase the accessibility and competitiveness of public transport against motoring transport to ensure that regional enlargement is achieved in a sustainable way. The vision for transit-oriented development (TOD) in Östergötland derives from a regional planning level and in order to implement the vision in municipal planning, it is important to specify how both the municipality and the region can benefit. An approach is to find a model that can raise the regional perspective in the local planning process. The purpose of this study is to develop a densification model that focuses on TOD in smaller urban areas. A densification model for the Stockholm region has previously been developed in conjunction with the regional development plan, and this study examines whether the model can be adapted to TOD planning in smaller urban areas. The densification model has been modified methodically with the help of two planners in Östergötland as well as a literature review on regional development and TOD. The custom model has been tested in two separate case studies and the results comprise a mapping of the potential for densification described in three different densification scenarios; municipal focus areas for densification, market interesting development areas and consensus development. This model enables the regional vision for TOD to be implemented into the municipal planning process and shows not only how both municipality and the region can benefit from a partnership, but also the critical problems that each individual municipality must overcome in order to continue to develop in the future.

Transit Oriented Development theoretical and practical framework represents an important tool for municipalities, private actors and citizens to enhance quality of life in urban contexts. Planning cities that encourage sustainable mobility patterns can contribute to aim at diversifying land use and making cities more accessible, safer and attractive for people. Handen has developed as a car-dependant area that is planned to growth its population and build more than 9000 new housing units by 2030 (Haninge Kommun, 2016). The TOD standard 3.0 was applied in the area around Handen pendeltåg station, to practically assess the TODness level of the area and provide recommendations to take into a consideration for future and current developments. Using the TOD standard in Handen can contribute to aim at a more sustainable growth pattern for both current and expected new citizens on the area. After implementing the evaluation system, it was found out that the best ranked variables were Compactness and Cycling. In contrast the variables that received the lowest scores were Walk, Densify, Connect, and Shift. Overall, Handen scored a Bronze level of TODness. Therefore, there are several actions that could be implemented on the study area in order to improve the TODness level. Specifically, Handen needs to diversify its land use, enhance the pedestrian network, encourage land mix use, decrease the space destined to cars and increase pedestrian connectivity, among others.

Bus rapid transit (BRT) is an innovative bus system with sophisticated vehicles and inflexible busways integrated in the cities, high capacity and high quality, high speed and frequency, distinctive image and comfort. Many in Sweden believe that is impossible to introduce BRT, even though the Swedish towns and cities can benefit from the image, speed and frequency that BRT symbolizes. The archipelago-like urbanization, urban sprawl and the uncompetitive journey times of public transportation compared with the private car are identified as main obstacles. New questions emerged: Is it possible to transform and adjust the Swedish towns and cities for BRT? What demands BRT? How is transit-oriented development (TOD) applicable in a Swedish context as a policy to integrate cities and BRT? In this licentiate thesis I investigate the interrelationship between bus transportation and neighborhoods, between BRT and urban form as well as the possibilities to introduce busways and BRT, to trigger TOD and to transform the Swedish towns and cities for BRT. Much has been written about BRT, but seldom by architects or urban planners and designers. BRT and TOD are seen though urban form and processes of urbanization within a morphological tradition established by Kevin Lynch. BRT is represented by paths and nodes that disperse distinctive attractiveness pattern of desirability cores that shape neighborhoods as districts. TOD is about synchronizing the everyday urban life with public transportation systems. BRT-TOD is defined as a policy to recognize desirability cores spread by the different infrastructures of BRT and promote development of urban form within their attractiveness pattern at urban and regional scale. BRT-TOD is discussed as a concept of BRT metropolis in context of the urbanization of Swedish towns and cities.  TOD is defined morphologically as public transport cities. A public transport city is a city that in its development adapted to specific public transportation systems. TOD is nothing new in Europe or Sweden. To find regularities of the effect of public transportation systems on cities I do a historical overview of the Swedish towns and cities. In the end the position of bus and BRT, public transport cities and TOD and possibilities of future urban transformation of the smaller and larger Swedish cities towards BRT metropolises are discussed in context of today’s “‘system’ of automobility” and widespread car society and the emerging knowledge society and its postmodern fringes of urbanization. / <p>QC 20130917</p>

This study investigates the institutional learning from attempts at securing affordable housing inclusion within Transit-Oriented Developments (TOD) through institutional change in Reykjavík, Iceland. As Reykjavík embarks on the ambitious City Line project, a bus-rapid transit network aimed at sustainably shaping urban growth, ensuring affordable housing near transit stations has become critical. Past attempts to achieve housing affordability have fallen short since Reykjavík still, to this day, experiences a great lack of affordable housing. Thus, this research employs an institutional learning framework to explore the barriers to and opportunities for ensuring affordable housing in TODs. Through expert interviews and document analysis, the study’s findings highlight the institutional challenges hindering the realisation of affordable housing goals within TODs. These include the vagueness of upper-level policies and terminology, the influence of land ownership, and implementation gaps in planning. Additionally, the research identifies opportunities for institutional change, such as strengthening standardisation from state-level policies, including principles of transit-accessible development in the extensions and re-evaluation of the City Line network, and addressing issues of timescale alignment between the implementation of TODs and the City Line. The study contributes to the limited Icelandic literature on institutional analysis in urban planning and offers ideas for enhancing social inclusivity and housing accessibility for Reykjavík’s future transit communities.