37 research outputs found

    A new formal and analytical process to product modeling (PPM) method and its application to the precast concrete industry

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    The current standard product (data) modeling process relies on the experience and subjectivity of data modelers who use their experience to eliminate redundancies and identify omissions. As a result, product modeling becomes a social activity that involves iterative review processes of committees. This study aims to develop a new, formal method for deriving product models from data collected in process models of companies within an industry sector. The theoretical goals of this study are to provide a scientific foundation to bridge the requirements collection phase and the logical modeling phase of product modeling and to formalize the derivation and normalization of a product model from the processes it supports. To achieve these goals, a new and formal method, Georgia Tech Process to Product Modeling (GTPPM), has been proposed. GTPPM consists of two modules. The first module is called the Requirements Collection and Modeling (RCM) module. It provides semantics and a mechanism to define a process model, information items used by each activity, and information flow between activities. The logic to dynamically check the consistency of information flow within a process also has been developed. The second module is called the Logical Product Modeling (LPM) module. It integrates, decomposes, and normalizes information constructs collected from a process model into a preliminary product model. Nine design patterns are defined to resolve conflicts between information constructs (ICs) and to normalize the resultant model. These two modules have been implemented as a Microsoft Visio ™ add-on. The tool has been registered and is also called GTPPM ™. The method has been tested and evaluated in the precast concrete sector of the construction industry through several GTPPM modeling efforts. By using GTPPM, a complete set of information items required for product modeling for a medium or a large industry can be collected without generalizing each company's unique process into one unified high-level model. However, the use of GTPPM is not limited to product modeling. It can be deployed in several other areas including: workflow management system or MIS (Management Information System) development software specification development business process re-engineering.Ph.D.Committee Chair: Eastman, Charles M.; Committee Co-Chair: Augenbroe, Godfried; Committee Co-Chair: Navathe, Shamkant B.; Committee Member: Hardwick, Martin; Committee Member: Sacks, Rafae

    Advanced digital signal processing for coherent optical OFDM transmissions

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    Coherent optical orthogonal frequency division multiplexing (CO-OFDM) has been actively considered as a potential candidate for long-haul transmission and 400 Gb/s to 1 Tb/s Ethernet transport because of its high spectral efficiency, efficient implementation, flexibility and robustness against linear impairments such as chromatic dispersion and polarization mode dispersion. However, due to the long symbol duration and narrow subcarrier spacing, CO-OFDM systems are sensitive to laser phase noise and fibre nonlinearity induced penalties. As a result, the development of CO-OFDM transmission technology crucially relies on efficient techniques to compensate for the laser phase noise and fibre nonlinearity impairments. In this thesis, high performance and low complexity digital signal processing techniques for laser phase noise and fibre nonlinearity compensation in CO-OFDM transmissions are demonstrated. For laser phase noise compensation, three novel techniques, namely quasipilot-aided, decision-directed-free blind and multiplier-free blind are introduced. For fibre nonlinear compensation, two novel techniques which are referred to as phase conjugated pilots and phase conjugated subcarrier coding, are proposed. All these abovementioned digital signal processing techniques offer high performances and flexibilities while requiring relatively low complexities in comparison with other existing phase noise and nonlinear compensation techniques. As a result of the developments of these digital signal processing techniques, CO-OFDM technology is expected to play a significant role in future ultra-high capacity optical network. In addition, this thesis also presents preliminary study on nonlinear Fourier transform based transmission schemes in which OFDM is a highly suitable modulation format. The obtained result paves the way towards a truly flexible nonlinear wave-division multiplexing system that allows the current nonlinear transmission limitations to be exceeded

    Resilient and Scalable Forwarding for Software-Defined Networks with P4-Programmable Switches

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    Traditional networking devices support only fixed features and limited configurability. Network softwarization leverages programmable software and hardware platforms to remove those limitations. In this context the concept of programmable data planes allows directly to program the packet processing pipeline of networking devices and create custom control plane algorithms. This flexibility enables the design of novel networking mechanisms where the status quo struggles to meet high demands of next-generation networks like 5G, Internet of Things, cloud computing, and industry 4.0. P4 is the most popular technology to implement programmable data planes. However, programmable data planes, and in particular, the P4 technology, emerged only recently. Thus, P4 support for some well-established networking concepts is still lacking and several issues remain unsolved due to the different characteristics of programmable data planes in comparison to traditional networking. The research of this thesis focuses on two open issues of programmable data planes. First, it develops resilient and efficient forwarding mechanisms for the P4 data plane as there are no satisfying state of the art best practices yet. Second, it enables BIER in high-performance P4 data planes. BIER is a novel, scalable, and efficient transport mechanism for IP multicast traffic which has only very limited support of high-performance forwarding platforms yet. The main results of this thesis are published as 8 peer-reviewed and one post-publication peer-reviewed publication. The results cover the development of suitable resilience mechanisms for P4 data planes, the development and implementation of resilient BIER forwarding in P4, and the extensive evaluations of all developed and implemented mechanisms. Furthermore, the results contain a comprehensive P4 literature study. Two more peer-reviewed papers contain additional content that is not directly related to the main results. They implement congestion avoidance mechanisms in P4 and develop a scheduling concept to find cost-optimized load schedules based on day-ahead forecasts

    Diversity and Production of Herbaceous Vegetation in a Northern Utah Subalpine Chronosequence

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    Successional trends in herbaceous plant production and diversity were studied in an age sequence of sites, i.e. chronosequence, inferred to represent a meadow to aspen to fir to spruce-fir sere. Primary production was observed to decrease in a linear fashion with successional development. Three components of diversity; richness, heterogeneity, and equitability or evenness, each had low early successional values, reaching maximum diversity in mid-succession, and declining to intermediate levels with maturity. The magnitude of these trends varied greatly, depending on the methods used to determine plant dominance. Characteristics of various dominance indices and their applicability to this study were examined. Mean daily photosynthetic biomass was found to be an especially appropriate index of dominance for studying these seasonally dynamic communities. A checklist of 141 vascular plant taxa encountered in the study is included. The flora was determined to be exceedingly species rich, with values of the calculated diversity indices among the highest reported in the literature reviewed. The limitations of diversity indices to sampled data is discussed

    PEACE AND CONFLICT IMPACT ASSESSMENT OF THE NIGER DELTA DEVELOPMENT COMMISSION’S INTER-VENTIONS IN ODI, BAYELSA STATE, NIGERIA

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    Development interventions are aimed at promoting positive change, but they can equally have negative impact, especially in conflict-prone contexts. Whereas existing studies on Odi and the Niger Delta at large mainly focused on the history, environ-ment, culture, conflict and security situations, the peace and conflict impact of Nige-rian government‘s socio-economic interventions in the area have not been fully ex-plored. This study, therefore, assessed the Niger Delta Development Commission‘s (NDDC) interventions, to determine their relationship with the Commission‘s man-date, strategies, and community needs; their interactions with the community; and their impact on the dynamics of peace and conflict in Odi, a community that has at-tracted many interventions after the 1999 massacre. The study adopted the grounded theory and case study research designs. Primary and secondary data were collected through key informant and in-depth interviews, official documents and non-participant observation. Fifty-four key informant interviews were conducted with seven members of the Traditional Ruling Council and the Community Development Committee, six religious leaders, five women leaders, five Youth Coun-cil executives, 24 project beneficiaries, 12 NDDC staff, and five NDDC consultants. Forty-seven in-depth interviews were also held with six school teachers, ten politi-cians, and two law enforcement agents in Odi, five international/non-governmental organisations staff, six activists, and eight academics and professionals. The Niger Delta Regional Development Master Plan, the NDDC Act, and website contents were consulted. Non-participant observations were carried out at NDDC project sites in Odi. The data gathered were content analysed. The NDDC integrated development strategy correlated with NDDC‘s mandate and people‘s needs. However, the Commission, in implementing its interventions, contra-vened some of its articulated guiding principles and policies like promoting good gov-ernance, transparency, participatory decision-making, and impact assessment. Also, inadequate community consultation caused dissonance in NDDC‘s and community‘s prioritisation of needs. Moreover, due to inadequate consideration for peace and con-flict sensitivity, the interventions produced series of positive and negative impact on peace and conflict dynamics in Odi. Construction of roads and educational facilities, rural electrification and training in modern agricultural practices impacted positively on the structural causes of conflict. They brought federal government‘s presence to Odi; provided income for male youths employed as labourers and for construction ma-terials‘ suppliers as well as capacity building in modern agricultural practices. How-ever, the community perceived the NDDC interventions as resources and competed for in a socio-political environment characterised by pervasive corruption and bad gov-ernance. This provided sufficient conditions for spirals of negative consequences that ultimately reduced the overall effectiveness of the interventions. The negative impact included entrenching corruption in intervention cycle, power disequilibrium between NDDC and Odi community, oppression and division, and gender inequality, commu-nal conflicts, and apathy. The Niger Delta Development Commission‘s interventions, intended for positive change, also had many negative consequences in Odi because the Commission failed to mainstream peace and conflict sensitivity in the interventions. The NDDC should therefore adhere strictly to its guiding principles and policies as well as international iibest practices in intervention programming in order to maximise the positive and minimise the negative impactsof its intervention

    Modeling and analysis of power processing systems: Feasibility investigation and formulation of a methodology

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    A review is given of future power processing systems planned for the next 20 years, and the state-of-the-art of power processing design modeling and analysis techniques used to optimize power processing systems. A methodology of modeling and analysis of power processing equipment and systems has been formulated to fulfill future tradeoff studies and optimization requirements. Computer techniques were applied to simulate power processor performance and to optimize the design of power processing equipment. A program plan to systematically develop and apply the tools for power processing systems modeling and analysis is presented so that meaningful results can be obtained each year to aid the power processing system engineer and power processing equipment circuit designers in their conceptual and detail design and analysis tasks

    FAST simplified vulnerability approach for seismic assessment of infilled RC MRF buildings and its application to the 2011 Lorca (Spain) earthquake

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    [EN] A simplified analytical method ("FAST") for the estimation of large-scale vulnerability of Reinforced Concrete (RC) Moment Resisting Frames with masonry infills is proposed and subsequently tested by using real damage scenario caused by the 2011 Lorca earthquake as a benchmark. FAST is a spectral-based approach that allows predicting the average non-structural Damage State expected for each class of building (defined by number of storeys, age of construction, infills ratio in plan and location) for a given demand level. It accounts for non-uniformity of infills in elevation, i.e. a reduction of infills ratio of the ground floor. FAST is based on: (i) the definition of approximated capacity curves of the infilled building, assuming that the RC frame is designed according to the corresponding seismic code; and on (ii) the assumption of "a priori" deformed shapes in accordance with the attainment of each non-structural damage state at 1st storey, estimated through experimental and numerical correlations. Two versions of FAST are proposed: a "simplified" approach aimed at the evaluation of uniformly infilled frames; and a "generalised" version which can account for any intermediate situation between uniformly infilled frames and pilotis frames (i.e. without infills at 1st storey). Also, some extensions of the method are highlighted. Aimed at testing FAST, the real damage scenario after the earthquake of Lorca (2011) is used as a benchmark, despite its impulsivity and directivity. In order to define the specific input parameters for the case study, information regarding ground motion, post-earthquake damage scenario and also building design practice must be collected. Hence, a detailed review of historical Spanish seismic codes and a critical analysis of current Spanish seismic code NCSE-02 in comparison with current reference performance-based codes such as Eurocode 8 are provided. Special emphasis is placed on provisions which can prevent a proper capacity design and that, in turn, can cause brittle failures or favour the interaction with infills. Also, the prescription of lower behaviour factor for wide-beam frames with respect to deep-beam frames -which is not present in most codes¿ is discussed; outcomes of several case studies suggest that such prescription is obsolete. Finally, FAST is applied to Lorca earthquake and predicted damage scenarios are obtained, considering different assumptions for input values. Results show proper agreement between predicted and real damages. Structural collapses were rarely observed, even though the PGA was three times higher than the typical acceleration of design, so FAST proves that masonry infills provided additional strength to RC frames.[ES] Se propone un método analítico simplificado ("FAST") para la estimación de la vulnerabilidad a gran escala de edificios porticados de hormigón armado con tabiquería de fábrica, posteriormente testeado mediante la adopción del escenario de daño real correspondiente al terremoto de Lorca de 2011 como patrón de comparación. FAST es un procedimiento espectral que permite predecir el nivel de daño no estructural medio esperado para cada clase de edificio (definido por su número de plantas, año de construcción, densidad de tabiquería en planta y localización geográfica), considerando un nivel de demanda dado. El método tiene en cuenta la irregularidad de la tabiquería en alzado, es decir, la posible reducción relativa de tabiquería en planta baja. FAST se basa en: (i) la definición de curvas de capacidad aproximadas para los edificios tabicados, asumiendo que la estructura de HA se ha proyectado según la norma sísmica correspondiente en cada caso; y en (ii) la asunción de deformadas "apriorísticas" coherentes con cada grado de daño (suponiendo que éste se alcanza siempre en planta baja), estimadas a través de correlaciones experimentales y numéricas. Se proponen dos versiones de FAST: una "simplificada" para la evaluación de edificios uniformemente tabicados en altura, y otra "generalizada", que es capaz de tener en cuenta cualquier situación intermedia entre el prototipo uniformemente tabicado y el de planta baja diáfana. Además, se proponen ciertas extensiones al método. A fin de validar FAST, se elige el escenario de daño real correspondiente al terremoto de Lorca (2011) como patrón de comparación, a pesar de su impulsividad y directividad. Para definir los parámetros de input correspondientes al caso de estudio, es necesario recopilar previamente la información concerniente a la señal sísmica, el escenario de daño y las características del parque construido. Por tanto, se lleva a cabo una revisión exhaustiva de las normas sísmicas históricas en España y un análisis crítico de la norma sísmica española actual NCSE-02 en comparación con otras normas actuales de referencia basadas en el desempeño, como el Eurocódigo 8, haciendo énfasis en las provisiones que no garantizan el diseño por capacidad y que por tanto pueden provocar mecanismos frágiles o favorecer la excesiva influencia de la tabiquería. Además, se discute sobre la restricción del coeficiente de ductilidad en estructuras de vigas planas, cuestión que no se refleja en otras normas. Los resultados obtenidos mediante análisis de casos de estudio muestran que dicha prescripción resulta obsoleta para normas actuales. Finalmente, FAST se aplica al caso del terremoto de Lorca, obteniéndose predicciones de daño medio para diferentes asunciones. Los resultados muestran una coincidencia aceptable entre la predicción y los daños reales. FAST confirma que la causa principal de la práctica ausencia de colapsos (ante un terremoto con PGA triple que la típica de proyecto) hay que buscarla en la contribución estructural de la tabiquería de fábrica.[CA] Es proposa un mètode analític simplificat ("FAST") per a l'estimació de la vulnerabilitat a gran escala d'edificis porticats de formigó armat amb envans de fàbrica. Posteriorment, el mètode ha estat testejat mitjançant l'adopció de l'escenari de dany real corresponent al terratrèmol de Lorca de 2011 com a patró de comparació. FAST és un procediment espectral que permet predir el nivell de dany no estructural mitjà esperat per a cada classe d'edifici (definit pel seu nombre de plantes, any de construcció, densitat d'envans en planta i localització geogràfica), considerant un determinat nivell de demanda. El mètode té en compte la irregularitat de la distribució de envans al llarg de les diferents plantes del edifici. Es a dir, es pot tenir en compte que, freqüentment, hi ha una menor quantitat de d'envans a la planta baixa. FAST es fonamenta en: (i) la definició de corbes de capacitat aproximades que tenen en compte no sols la estructura del edifici sinó també els envans i assumint que l'estructura de HA s'ha projectat segons la norma sísmica corresponent en cada cas; (ii) l'assumpció de deformades "apriorístiques" coherents amb cada grau de dany (suposant que aquest es dona sempre a la planta baixa) que han estat estimades a través de correlacions experimentals i numèriques. Es proposen dues versions de FAST: una "simplificada" per a l'avaluació d'edificis amb envans uniformement repartits per totes les plantes, i una altra "generalitzada", que és capaç de tenir en compte qualsevol situació intermèdia entre el prototip uniformement paredat i el de planta baixa diàfana. A més, es proposen certes extensions al mètode. Per tal de validar FAST, es tria l'escenari de dany real corresponent al terratrèmol de Lorca (2011) com a patró de comparació, malgrat la seva impulsivitat i directivitat. Per definir els paràmetres de entrada corresponents al cas d'estudi, cal recopilar prèviament la informació concernent al senyal sísmica, l'escenari de dany i les característiques del parc construït. Per tant, es porta a terme una revisió exhaustiva de les normes sísmiques històriques a Espanya i una anàlisi crítica de la norma sísmica espanyola actual (NCSE-02) comparant-la amb altres normes actuals de referència, com l'Eurocodi 8, fonamentat en el concepte d'acompliment. També es fa èmfasi a les provisions que no garanteixen el disseny per capacitat i que, per tant, poden provocar mecanismes de col·lapse fràgils o afavorir la interacció de la estructura amb els envans. A més, es discuteix sobre la restricció del coeficient de ductilitat de les estructures de bigues planes ja que es una qüestió que no aborden la majoria de les normes. Els resultats obtinguts mitjançant l'anàlisi de casos d'estudi mostren que aquesta restricció resulta obsoleta a les normes actuals. Finalment, FAST s'aplica al cas del terratrèmol de Lorca, obtenint prediccions de dany mitjà per a diferents combinacions del paràmetres de entrada. Els resultats mostren una coincidència acceptable entre la predicció i els danys reals. FAST confirma que la causa principal de la pràctica absència de col·lapses (davant un terratrèmol amb PGA triple que la típica de projecte) cal buscar-la en la contribució estructural dels envans.Gómez Martínez, F. (2015). FAST simplified vulnerability approach for seismic assessment of infilled RC MRF buildings and its application to the 2011 Lorca (Spain) earthquake [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/54780TESISPremios Extraordinarios de tesis doctorale

    Towards radio access network intelligence in mobile communication systems beyond 5G

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    This final degree thesis is part of a project of the Mobile Communications Research Group (GRCM) of the Polytechnic University of Catalonia. The project is focused on the development of operations and management mechanisms and algorithms that with the use of artificial intelligence and machine learning in the 5G era and the next generations, integrate user equipment as part of the intelligence of the end-to-end connected network. This would materialise data analytics solutions that would not need to expose the network to a large amount of raw data collected by UEs. In this context, the aim of this thesis is to create a local network in order to test the different algorithms that lead to the intelligence of the radio access network in an environment beyond 5G. This includes configuring and analysing the performance of the assembled network as well as understanding the operation of each of its component parts.Esta tesis de final de grado forma parte de un proyecto del Grupo de Investigación en Comunicaciones Móviles (GRCM) de la Universidad Politécnica de Cataluña. El proyecto está enfocado al desarrollo de mecanismos y algoritmos de mantenimiento y gestión que con el uso de la inteligencia artificial y el aprendizaje autónomo en la era del 5G y las siguientes generaciones, integre los equipos de usuario como parte de la inteligencia de la red conectada de extremo a extremo. De esta manera se materializaría soluciones de análisis de datos que no necesitarían exponer a la red a una gran cantidad de datos recopiladas en bruto por los equipos de usuario. En este contexto, el objetivo de esta tesis en crear una red local para poder testear los diferentes algoritmos que lleven a la inteligencia de la red de acceso en un entorno más allá del 5G. Esto incluye configurar y analizar las prestaciones de la red montada además de entender el funcionamiento de cada una de las partes que la componen.Aquesta tesi de final de grau forma part d'un projecte del Grup de Recerca en Comunicacions Mòbils (GRCM) de la Universitat Politècnica de Catalunya. El projecte està enfocat al desenvolupament de mecanismes i algoritmes d'operació i gestió que amb l'ús de la intel·ligència artificial i l'aprenentatge autònom a l'era del 5G i les següents generacions, integri els equips d'usuari com a part de la intel·ligència de la xarxa connectada d'extrem a extrem. D' aquesta manera es materialitzaria solucions d'anàlisis de dades que no necessitarien exposar a la xarxa a una gran quantitat de dades recopilades en brut pels equips d'usuari. En aquest context, l'objectiu d'aquesta tesis es crear una xarxa local per a poder testejar els diferents algoritmes que portin a la intel·ligència de la xarxa d'accés en un entorn més enllà del 5G. Això inclou configurar i analitzar les prestacions de la xarxa muntada a més d'entendre el funcionament de cadascuna de les parts que la composen

    Deployable tension-strut structures: Concept, structural behaviour and implementation

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    Ph.DDOCTOR OF PHILOSOPH
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