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Thèses sur le sujet « Dimensione temporale »
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1
Pante', Serena. « La dimensione spazio-temporale nella Frühe Neuzeit. Il caso del Fortunatus ». Doctoral thesis, Università di Palermo, 2009. http://hdl.handle.net/10447/171721.
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Granello, Daniel. « La dimensione temporale nell'opera "Se questo é un uomo" di Primo Levi ». Thesis, Högskolan Dalarna, Italienska, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:du-3710.
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Martini, Chiara <1991>. « Vivere l’(im)mobilità : un'etnografia della dimensione temporale delle persone emigranti lungo le rotte balcaniche ». Master's Degree Thesis, Università Ca' Foscari Venezia, 2022. http://hdl.handle.net/10579/21426.
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Negli ultimi anni il concetto di crisi ed emergenza ha pervaso il discorso pubblico in Europa (crisi economica, crisi dei rifugiati, crisi sanitaria) e nell’ambito della gestione dei flussi migratori ha influenzato l’adozione di politiche sempre più restrittive, emergenziali e di controllo. La rotta balcanica, o meglio, le rotte balcaniche, che negli ultimi anni si sono create e sono state attraversate da numerosi e diversi flussi di persone, rappresentano un territorio paradigmatico su cui vengono sperimentate pratiche di controllo, assoggettamento e precarizzazione a danno delle persone in transito. La loro vita è costellata da dinamiche e strutture che creano una costante tensione tra mobilità e immobilità, tra accelerazioni e attese, con ovvie e diverse conseguenze su traiettorie, progetti migratori ed agency. La Grecia e i paesi dei Balcani rappresentano due casi emblematici di ciò che determinate politiche di controllo e chiusura possono produrre, sia nel macro che a livello individuale. La presente ricerca cercherà quindi di analizzare tali contesti focalizzandosi sulla dimensione temporale, sia come dimensione sulla quale agiscono le pratiche di controllo e governo dei fenomeni migratori, sia come esperienza che influisce sulle soggettività, sull’agency e sui percorsi migratori. Nelle zone di confine le persone in movimento, richiedenti asilo e migranti, non solo si ritrovano a vivere prolungati periodi di attesa, senza limiti e prospettive precise, ma affrontano quello che di fatto è una usurpazione e privazione del loro tempo, in una logica di controllo dei loro movimenti. Procedure burocratiche sempre più prolungate, sistemi di asilo non adeguati, la gestione dei confini interni ed esterni, il sistema hotspot e dei campi: tutto ciò rientra nelle diverse dinamiche che costringono le persone in movimento a bloccare, decelerare, posticipare, rimandare traiettorie, percorsi e progetti migratori. A partire da una analisi delle politiche migratorie europee e nazionali (nello specifico di Grecia e Bosnia-Erzegovina), dell’attuale configurazione delle rotte che attraversano l’area balcanica, del regime dei confini e dei cambiamenti avvenuti dall'inizio della pandemia di CoVid-19, si cercherà di indagare gli effetti e le conseguenze delle attese forzate e dello stato di a-temporalità sull’agency e sui percorsi migratori e di individuare le strategie che le persone in transito mettono in atto, inquadrando le situazioni all’interno di dinamiche di precarizzazione e di creazione di nuove forme di inclusione ed esclusione.
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RIGAMONTI, ALESSANDRA. « Apprendere dai ritmi. Una ricerca composizionale con operatori dell’affido familiare ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2019. http://hdl.handle.net/10281/241181.
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L’affido familiare è un processo sistemico complesso e temporaneo, che coinvolge molti attori (bambini, operatori, famiglia affidataria, famiglia d’origine, istituzioni, Tribunale), coinvolti in processi di apprendimento interconnessi e interdipendenti, determinati da temporalità esplicite e implicite, nelle quali si intrecciano dimensioni sistemiche, sociali e culturali. Il concetto di tempo è stato scelto in questo lavoro per mettere a fuoco la complessità, la composizione e il coordinamento tra questi processi incorporati e simultanei. Da una prospettiva pedagogica, la ricerca si interroga in particolare sul ritmo come categoria analitica e pratica nei processi di affido familiare: da cosa è determinato e cosa determina? Queste domande di ricerca sono volte a delineare una teoria/modello del ritmo nei processi di affido, che possa ispirare la formazione degli operatori impegnati nei processi di affido in modo utile e innovativo.
La cornice metodologica della ricerca è narrativa, partecipativa e interpretativa. Sono state condotte 18 interviste semi-strutturate a ricercatori e professionisti, centrate sulla rappresentazione e sulla pertinenza del concetto di ritmo per pensare i processi di affido. Un secondo studio ha realizzato una co-operative inquiry con il coinvolgimento diretto e la com-partecipazione di 12 operatori, con i quali si sono esplorate criticamente le cornici di significato e le teorie implicite e le loro implicazioni pratiche riguardanti le dimensioni temporali che sostengono, nascondono o trasformano i ritmi individuali, relazionali e istituzionali. Una delle riflessioni ricorrenti nell’analisi dei dati è stata la presenza di ritmi antagonisti, contradditori e complementari. Queste polarità ritmiche aiutano a riconoscere la complessità, la composizione e il superamento degli opposti, verso il coordinamento delle dimensioni temporali e dei loro effetti sui processi di affido.Foster care is a complex and temporary process in which many actors (children, social workers, birthparents, foster families, social and health agencies, court) are involved, interacting and learning by their explicit and implicit temporalities intertwined with systemic, social and cultural dimensions. Thus, the concept of rhythm has been used in this work to illuminate the complexity, composition and coordination of these embodied and simultaneous processes. From a pedagogical view, this research will investigate rhythm, as an analytical and practical category in foster care: how does it affect and is affected by foster care processes? These research questions are aimed at outlining a theory/model of rhythm in foster care processes, apt to inspire useful and innovative professional training for professionals in foster care. A narrative, participatory and interpretative methodological framework guides the research. Semi-structured interviews with 18 researchers and professionals were used to explore their representations and the pertinence of the concept of rhythm in thinking about foster cares. A second study was based on a co-operative inquiry with 12 practitioners, aimed at illuminating the frames of meaning and implicit theories, as well as practical implications, regarding the temporal dimensions which may sustain, hinder or transform individual, relational and institutional rhythms. A main line of reflection from the analysis of data concerns the presence of antagonistic, contradictory, and complementary rhythms in foster care. These rhythmic polarities sustain the recognition of complexity, the composition and the overcoming of the opposing dimensions, towards the coordination of temporal dimensions and their effects in foster care.
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Field, Luke V. « The Temporal Dimension of Architecture ». University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1236114237.
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RULA, ANISA. « Time-related quality dimensions in linked data ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2014. http://hdl.handle.net/10281/81717.
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Over the last few years, there has been an increasing di↵usion of Linked Data as a standard way to publish interlinked structured data on the Web, which allows users, and public and private organizations to fully exploit a large amount of data from several domains that were not available in the past. Although gathering and publishing such massive amount of structured data is certainly a step in the right direction, quality still poses a significant obstacle to the uptake of data consumption applications at large-scale. A crucial aspect of quality regards the dynamic nature of Linked Data where information can change rapidly and fail to reflect changes in the real world, thus becoming out-date. Quality is characterised by di↵erent dimensions that capture several aspects of quality such as accuracy, currency, consistency or completeness. In particular, the aspects of Linked Data dynamicity are captured by Time-Related Quality Dimen- sions such as data currency. The assessment of Time-Related Quality Dimensions, which is the task of measuring the quality, is based on temporal information whose collection poses several challenges regarding their availability, representation and diversity in Linked Data. The assessment of Time-Related Quality Dimensions supports data consumers in their decisions whether information are valid or not. The main goal of this thesis is to develop techniques for assessing Time-Related Quality Dimensions in Linked Data, which must overcome several challenges posed by Linked Data such as third-party applications, variety of data, high volume of data or velocity of data. The major contributions of this thesis can be summarized as follows: it presents a general settings of definitions for quality dimensions and measures adopted in Linked Data; it provides a large-scale analysis of approaches for representing temporal information in Linked Data; it provides a sharable and interoperable conceptual model which integrates vocabularies used to represent temporal information required for the assessment of Time-Related Quality Di- mensions; it proposes two domain-independent techniques to assess data currency that work with incomplete or inaccurate temporal information and finally it pro- vides an approach that enrich information with time intervals representing their temporal validity.
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Sabiu, Bianca. « Studio della risposta temporale di SiPM accoppiati secondo differenti configurazioni spaziali a scintillatori plastici di diverse dimensioni ». Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
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Il presente elaborato di tesi si pone come obiettivo lo studio, attraverso l'utilizzo di un telescopio per raggi cosmici, della risoluzione temporale di rivelatori di particelle basati su SiPM (Silicon PhotoMultiplier) accoppiati a scintillatori plastici.
In particolare, dopo aver effettuato uno scan in tensione dei SiPM, sono state analizzate diverse modalità di accoppiamento degli stessi rispetto agli scintillatori e due differenti dimensioni degli scintillatori stessi.
Una sempre maggiore precisione nella misura di informazione temporale mediante l'uso di questo tipo di rivelatori è di fondamentale importanza in vari e numerosi ambiti: dagli esperimenti sulle misure del tempo di volo (TOF, Time Of Flight) in fisica nucleare e subnucleare, alla loro applicazione in tecniche di diagnostica medica avanzata (ad esempio per la PET, Positron Emission Tomography) in campo medico.
I risultati raggiunti dall'analisi della risposta temporale dei SiPM in accoppiamento agli scintillatori plastici si sono rivelati più vantaggiosi per la configurazione che vede i SiPM posizionati sui lati opposti dello scintillatore rispetto a quella in cui sono adiacenti allo stesso lato. In generale, è risultato più conveniente operare con SiPM mantenuti a basse tensioni di bias.
Infine, anche se sono stati ottenuti buoni risultati per gli scintillatori di dimensioni 0.5x0.5x1.0 cm^3, la migliore risoluzione temporale, di 65±10 ps, si è osservata con SiPM accoppiati agli estremi opposti di scintillatori di dimensioni 2.0x3.0x2.0 cm^3.
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Rizzo, Stefano Giovanni <1987>. « Temporal Dimension of Text : Quantification, Metrics and Features ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amsdottorato.unibo.it/8004/7/tesi.pdf.
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The time dimension is so inherently bound to any information space that it can hardly be ignored when describing the reality, nor can be disregarded in interpreting most information. In the pressing need to search and classify a larger amount of unstructured data with better accuracy, the temporal dimension of text documents is becoming a crucial property for information retrieval and text mining tasks.
Of all the features that characterize textual information, the time dimension is still not fully regarded, despite its richness and diversity. Temporal information retrieval is still in its infancy, while time features of documents are barely taken into account in text classification.
The temporal aspects of text can be used to better interpret the relative truthiness and the context of old information, and to determine the relevance of a document with respect to information needs and categories.
In this research, we first explore the temporal dimension of text collections in a large scale study on more than 30 million documents, quantifying its extent and showing its peculiarities and patterns, such as the relation between the creation time of documents and the mentioned time.
Then we define a comprehensive and accurate representation of the temporal aspects of documents, modeling ad-hoc temporal similarities based on metric distances between time intervals.
Results of evaluation show taking into account the temporal relevance of documents yields a significant improvement in retrieval effectiveness, over both implicit and explicit time queries, and a gain in classification accuracy when temporal features are involved.
By defining a set of temporal features to comprehensively describe the temporal scope of text documents, we show their significant relation to topical categories and how these proposed features are able to categorize documents, improving the text categorization tasks in combination with ordinary terms frequencies features.
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Chen, Linchao. « Predictive Modeling of Spatio-Temporal Datasets in High Dimensions ». The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1429586479.
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Stejmar, Carl. « Temporal Anti-Aliasing and Temporal Supersampling in Three-Dimensional Computer Generated Dynamic Worlds ». Thesis, Linköpings universitet, Institutionen för systemteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-129519.
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This master thesis investigates and evaluates how a temporal component can help anti-aliasing with reduction of general spatial aliasing, preservation of thin geometry and how to get temporal stability in dynamic computer generated worlds. Of spatial aliasing, geometric aliasing is in focus but shading aliasing will also be discussed. Two temporal approaches are proposed. One of the methods utilizes the previous frame while the other method uses four previous frames. In order to do this an efficient way of re-projecting pixels are needed so this thesis deals with that problem and its consequences as well. Further, the results show that the way of taking and accumulating samples in these proposed methods show improvements that would not have been affordable without the temporal component for real-time applications. Thin geometry is preserved up to a degree but the proposed methods do not solve this problem for the general case. The temporal methods' image quality are evaluated against conventional anti-aliasing methods subjectively, by a survey, and objectively, by a numerical method not found elsewhere in anti-aliasing reports. Performance and memory consumption are also evaluated. The evaluation suggests that a temporal component for anti-aliasing can play an important role in increasing image quality and temporal stability without having a substantial negative impact of the performance with less memory consumed.
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Stacey, Michael R. « A framework for multi-dimensional online temporal abstraction ». View thesis, 2009. http://handle.uws.edu.au:8081/1959.7/43262.
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Thesis (Ph.D.)--University of Western Sydney, 2009.A thesis presented to the University of Western Sydney, College of Health and Science, School of Computing and Mathematics, in fulfilment of the requirements for the degree of Doctor of Philosophy. Includes bibliographies.
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Backman, Ronald Bruce. « A temporal 3D-registration framework for computer-integrated surgery ». University of Western Australia. Dept. of Computer Science, 1999. http://theses.library.uwa.edu.au/adt-WU2003.0012.
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Traditionally, volumetric modalities such as CT and MRI have provided static snapshots of anatomy enabling insight into the progression of disease and to the severity of injury. Recently, 3D-registration algorithms, originating in the neurosurgical field, have been used to merge these images resulting in richer visualizations. However, in situations where trauma patients are unable to be moved or are at risk of infection, there have been comparatively few advances. This thesis presents a 3D-registration framework that supports longitudinal study of morphologic changes in surface images of the upper body based on an optical technique - structured light imaging. The framework incorporates soft-tissue deformation modeling to allow coordinate frame determination and specific point tracking required for applications of Computer-Integrated Surgery. The framework is implemented in three stages using a coarse-fine approach that separately addresses the different sources of registration error commonly found in temporal registration applications. The coarse stage defines seven thoracic fiducials that form a rigid body. A special anthropomorphic stand is designed and used to enforce a rigid body assumption. Experimental results show the fiducials to have precision of approximately 2 mm. The medium stage incorporates the novel use of ultraviolet light as a surface registration technique. UV is used to avoid error caused when the projected light stripes interfere with the marker material - a common problem with external landmarks and optical assessment systems. A semi-automatic algorithm for identifying the centre of the fiducials is given and shown to be highly accurate - to within 1 pixel precision compared to the visually assessed centre. The movement of these fiducials is also modelled at the extremes of the respiratory cycle with individual fiducials moving from 5-17 mm. A least-squares algorithm is implemented to bring surfaces together based on their fiducial locations and rigid-body motion. This algorithm results in RMS error of approximately 1.17 +/- 0.45 mm. The fine stage involves finding fixed point correspondences in changed regions between a base surface and a comparison surface acquired at a different time given the rigid body registration from the previous stages. Five algorithmic variants are assessed using two simulations of thoracic swelling. The results do not show statistical significance between variants but do indicate visually some promising results. An application of this framework could be the near real-time guidance of the FAROArm, a precision measuring instrument commonly used in Computer-Integrated Surgery, to these points. This would facilitate the collection of functional information of clinical interest while maintaining positional congruence with data acquired at a different time point.
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Plumejeaud, Christine. « Modèles et méthodes pour l'information spatio-temporelle évolutive ». Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00630984.
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Cette thèse se situe dans le domaine de la modélisation spatio-temporelle, et nos travaux portent plus particulièrement sur la gestion de l'information statistique territoriale. Aujourd'hui, la mise à disposition d'un grand volume d'informations statistiques territoriales par différents producteurs (Eurostat, l'INSEE, l'Agence Européenne de l'Environnement, l'ONU, etc.) offre une perspective d'analyses riches, permettant de combiner des données portant sur des thématiques diverses (économiques, sociales, environnementales), à des niveaux d'étude du territoire multiples : du local (les communes) au global (les états). Cependant, il apparaît que les supports, les définitions, les modalités de classification, et le niveau de fiabilité de ces données ne sont pas homogènes, ni dans l'espace, ni dans le temps. De ce fait, les données sont difficilement comparables. Cette hétérogénéité est au cœur de notre problématique, et pour lui faire face, c'est-à-dire l'appréhender, la mesurer et la contrôler, nous faisons dans cette thèse trois propositions pour permettre in fine une exploitation avisée de ce type de données. La première proposition a pour cible le support de l'information statistique territoriale, et cherche à rendre compte à la fois de son caractère évolutif et de son caractère hiérarchique. La deuxième proposition traite du problème de variabilité sémantique des valeurs statistiques associées au support, au moyen de métadonnées. Nous proposons un profil adapté du standard ISO 19115, facilitant l'acquisition de ces métadonnées pour des producteurs de données. La troisième proposition explore la mise à disposition d'outils pour analyser et explorer ces informations dans un mode interactif. Nous proposons une plate-forme dédiée aux analyses statistiques et visant à repérer des valeurs exceptionnelles (outliers en anglais), et à les mettre en relation avec leur origine, et les modalités de leur production.
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Lucarelli, Andrea. « The Political Dimension of Place Branding ». Doctoral thesis, Stockholms universitet, Företagsekonomiska institutionen, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-123689.
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Place branding is commonly understood as the application of marketing and commercial ideas, strategies, measurements and logic to the realm of places such as cities, regions and nations. Nevertheless, place branding is also understood as the locus where political activities – imbued with political impact and political effects – appear and affect the soft and hard infrastructures of urban agglomeration and other spatial environments. In this regard, by performing an analysis that helps unpack the multiple characters and impacts of political structures and processes in relation to place branding activities, the present dissertation aims to offer a conceptualization of the political dimension of place branding. By drawing on the critical assessment of the academic literature on place branding and on a series of studies about the branding processes in the region of Romagna and in the Greater Stockholm, the present dissertation further specifies an alternative conceptual framework (i.e. ecological politics) that suggests how place branding should be seen an empirical and theoretical political apparatus that acts, in praxis, based on an emerging, multifaceted and spatio-temporal enfolding of politics. More specifically, the ecological politics of place branding is characterized by four main aspects: the unfolding of a biopolitical ecology around place-branding practices; the ideological appropriation of place-branding processes; the positioning through politicized actions between the interest groups; and finally place-branding as a process of policy-intervention. Finally, on more general level, the present dissertation, by recognizing the political activities and efforts of place branding as crucial elements to be analyzed, makes the case for a more explicit, complex and manifold political analysis of the political dimension of place branding, which allows attention to be given to the impact that branding processes, practices and activities have on cities, regions and nationsAt the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Manuscript.
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Baskaran, Savitha. « Visualization of spatio-temporal data in two dimensional space ». Thesis, Purdue University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10246961.
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Spatio-temporal data is becoming very popular in the recent times, as there are large number of datasets that collect both location and temporal information in the real time. The main challenge is that extracting useful insights from such large data set is extremely complex and laborious. In this thesis, we have proposed a novel 2D technique to visualize the spatio-temporal big data. The visualization of the combined interaction between the spatial and temporal data is of high importance to uncover the insights and identify the trends within the data.
Maps have been a successful way to represent the spatial information. Additionally, in this work, colors are used to represent the temporal data. Every data point has the time information which is converted into relevant color, based on the HSV color model. The variation in the time is represented by transition from one color to another and hence provide smooth interpolation. The proposed solution will help the user to quickly understand the data and gain insights.
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Liviano, Solís Daniel. « Essays On Industrial Dynamics : Spatial And Temporal Dimensions Of Firm Entry ». Doctoral thesis, Universitat Rovira i Virgili, 2009. http://hdl.handle.net/10803/8448.
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DE LA TESIS DOCTORALSINOPSIS
Si esta tesis tuviera que ser definida con sólo unos pocos términos, uno de ellos sería
seguramente el de entrepreneurship (espíritu empresarial). Muchas de las contribuciones
procedentes de diferentes disciplinas han demostrado hasta qué punto las iniciativas
empresariales son una fuente importante de desarrollo económico. Tales iniciativas
pueden tener muchas formas y provenir de muchas fuentes, y un vehículo importante a
través del cual este tipo de iniciativas tienen un efecto en la economía es la entrada de
nuevas empresas. En este sentido, varias corrientes de la literatura se han centrado en
las características, determinantes y efectos de esas entradas. Este es el marco general de
este trabajo, que se centra en dos cuestiones fundamentales y relevantes: (a) los factores
determinantes de la localización territorial de nuevas empresas y (b) los efectos de esas
entradas en términos de demanda dinámica de factores productivos. Aunque estas
cuestiones se pueden analizar por separado, ambas pertenecen a un mismo fenómeno económico, es decir, las causas y las consecuencias económicas de la entrada de nuevas empresas, y los resultados obtenidos en cada análisis se pueden interpretar en un contexto más amplio y general.
If this thesis had to be defined just by using just few terms, one of them would
surely be entrepreneurship. Many contributions coming from different disciplines
have shown to what extent entrepreneurial initiatives are an important source of
economic development. Such initiatives can have many forms and come from many
sources, and an important vehicle through which such initiatives have an effect in
the economy is the entry of new economic business ventures. In this respect, several
streams of the literature have focused on the characteristics, determinants and
effects of such entries. This is the general framework of this work, which focuses
on two fundamental and relevant questions: (a) the territorial determinants of new
economic ventures' location and (b) the effects of such entries in terms of dynamic
factor demand. Although such questions can be analysed separately, they belong
to the same economic phenomenon, that is, the causes and consequences of new
economic ventures, and the results obtained in each analysis can be interpreted in a
broader and more general context.
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Neuhaus, F. « Urban rhythms : habitus and emergent spatio-temporal dimensions of the city ». Thesis, University College London (University of London), 2013. http://discovery.ucl.ac.uk/1396239/.
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This thesis focuses on the creation of space as an activity. The argu¬ment draws not only on aspects of movement in time, but also on a cultural and specifically social context influencing the creation of the spatial habitus. The aim of this thesis is to reconsider existing theories of time and space in the field of urban planning and design and develop an updated account of spatial activity, experience and space-making based on time. Recent developments in spatial practice, specifi¬cally those related to the development and widespread use of new technologies such as hand-held devices, make this an important and timely task. Integrating spatial-temporal dynamics into the way we think about cities will aid the implementation of sustainable forms of urban planning and design by activating the individual urban context. Repetition and pattern are properties of such a time-based ur¬ban environment. These properties result from activities guided according to time windows. For instance, we all experience the syn¬chronised and collective activities of the morning or evening rush hour, the lunchtime run to the restaurant, or a walk in the park on a Sunday. This orchestration of thousands of fellow urban dwellers is a time-related and spatial phenomenon. Urban habitus, or these types of everyday repetitive cycles of activity, is interpreted in this thesis as the factor linking the social and spatial organisation of the urban environment. While such patterns have been understood to be an important factor for understanding urban existence, there have been few ef¬fective methods for activating such patterns at both the larger scale and the scale of the individual. This thesis develops an innovative methodology for the description of spatial narratives in the context of urban living. This telescoping methodology, moving between the general patterns of the macro-scale and the lived-experience at the micro-scale, is developed in tandem with a re-conceptualisation of the city in time and space. The study is composed of two parts using two different cases. The first case is based on fieldwork tracking individual movement and the spatial extension of everyday routines. GPS technology is deployed, together with interviews and mental maps as the main method of investigation into spatial experience, the creation of per¬sonal space, and the orientation and organisation of spatial practice. The second case utilises online social networking data mined from the micro-blogging platform Twitter. The data of thousands of users is analysed regarding temporal patterns across urban areas. This method is used as a complementary investigation of urban tempo-rality on the level of the collective. Along the shifting locations and moving patterns of activity, the temporal morphology of an urban centre, a city, is visualised, thus revealing the constitution of urban space as a product of the collective. One of the key elements in the conclusion to this thesis is the definition of temporality as a status rather than a transition. This proposition deviates from the usual approach of merging time and space as time-space, whilst preserving both spatial and temporal qualities. Temporality is defined as the dimension of activity that has its own comprehensiveness involving time and space. It is no longer just something ephemeral or fleeting. Nor is it simply a Kantian container for activity. Through repetitive practices, time has presence and agency in our everyday lives. KEYWORDS: time, space, rhythm, cycle, temporality, habitus, urban, city, GPS tracking, social networks, Twitter data
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Kang, Lei. « Reduced-Dimension Hierarchical Statistical Models for Spatial and Spatio-Temporal Data ». The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1259168805.
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Palacios, Pastrana Florencio Edmundo. « Etude des rapports entre linguistique et logique concernant la dimension temporelle : un modèle de transition ». Université Joseph Fourier (Grenoble), 1998. http://www.theses.fr/1998GRE10273.
Texte intégralRésumé :
Le but general de cette these est de developper un langage formel susceptible de modeliser certains traits du langage naturel ayant une relation forte avec le temps. En particulier nous sommes interesse par la notion linguistique de l'aspect et de ses consequences logiques possibles. Nous basons notre analyse sur deux perspectives : linguistique et logique. Pour la premiere nous analysons les concepts pertinents lies a la categorie grammaticale de l'aspect, qui, avec la categorie du temps grammatical, a une relation directe avec la notion de temps. Pour la seconde perspective, nous analysons les notions logiques mises en jeu dans des systemes formels deductifs et leur relations avec le temps : la logique temporelle. Comme il est etabli, les langages formels bases sur les notions definies par frege ne sont pas suffisants pour exprimer toutes les composantes temporelles du langage naturel. Toutefois il y a d'autres formalismes etendus qui prennent en compte certains concepts linguistiques comme l'aspect. Une telle proposition a ete faite par galton qui introduit des operateurs pour certaines des notions aspectuelles les plus courantes en anglais comme la perfectivite et la progressivite. Notre proposition introduit des notions topologiques pour representer la structure de l'ensemble dans lequel un enonce prend une certaine valeur de verite. De plus nous traitons aussi du concept de sigma-signification pour representer certains concepts theoriques non ensemblistes en rapport avec la signification des enonces.
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Benouhiba, Fatma-Zohra. « Leprocessus d’héritage et la dimension temporelle dans le SGBD Scrabble ». Lyon, INSA, 1991. http://www.theses.fr/1991ISAL0031.
Texte intégralRésumé :
Aujourd'hui, les SGBD basés sur le modèle relationnel n'offrent pas toujours une solution satisfaisante aux exigences des nouvelles applications des bases de données, ce qui explique l'engouement actuel pour les modèles de données sémantiques et évolutifs. Ces modèles sont soit des nouveaux modèles intégrant des approches orientées objets, soit des extensions pour des modèles de données existants (relationnel, entité/association etc. ). Nous fusionnons les recherches système de gestion de bases de données dynamiques et des extensions introduites dans les modèles de représentation des connaissances afin de compléter le modèle des dépendances fonctionnelles en proposant de nouvelles extensions. La première partie de notre étude, concerne l'utilisation de la notion de spécialisation/généralisation pour définir un mécanisme d'héritage simple, multiple et sélectif. Ce mécanisme se représente par un ensemble de règles d'héritage et d'invariants. D'autre part, nous proposons un système de gestion des historiques des données ainsi que de· leur dynamique. Ceci nous permet d'introduire la notion de temps et de retracer l'historique des objets évolutifs. Le système permet également de définir un modèle d'évolution des données de la base exprimée par des règles d'évolution et des dépendances temporelles entre les objets. La seconde partie consiste à prendre en compte l'héritage dans le contexte dynamique et d'étendre le langage de définition de. La structure de la base ainsi que le langage d'interrrogationTodays DBMS based on the relational model do not always offer a solution which satisfies the requirements of new data bases application. This justifies the actual development trends of the semantic and evolutive models. . These models are either object oriented models or extensions to existing models (relational, entity/association etc. . . ). In order to complete the model with functional dependencies, by means of new extensions, we merge research works in the field of dynamical data base management systems and extensions introduced in models for knowledge representation. The first part of this study consists of the use of the notion of specialization / generalization in order to define a simple inheritance mechanism, which is multiple and selective. This mechanism is represented by a set of inheritance rules and invariants. On the other hand, we propose a system for the management of the histories and dynamics of data. This fact allows as to introduce the time and to redraw the histories of evolutive objects. The system allows also the defining of a model for the evolution of data base; this latter being expressed in terms o evolution laws and time dependencies between objects. The second part consists in taking into account of inheritance within the dynamical context and to extend the definition language of the base structure and the query language
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Wannous, Rouaa. « Computational inference of conceptual trajectory model : considering domain temporal and spatial dimensions ». Thesis, La Rochelle, 2014. http://www.theses.fr/2014LAROS023/document.
Texte intégralRésumé :
Le développement de technologies comme les systèmes de positionnement par satellites (GNSS), les communications sans fil, les systèmes de radio-identification (RFID) et des capteurs a augmenté la disponibilité de données spatio-temporelles décrivant des trajectoires d’objets mobiles. Des bases de données relationnelles peuvent être utilisées pour stocker et questionner les données capturées. Des applications récentes montrent l’intérêt d’une approche intégrant des trajectoires « sémantiques » pour intégrer des connaissances sur les comportements d’objets mobiles. Dans cette thèse, nous proposons une approche basée sur des ontologies. Nous présentons une ontologie pour les trajectoires. Nous appliquons notre approche à l’étude des trajectoires de mammifères marins. Pour permettre l’exploitation de nos connaissances sur les trajectoires, nous considérons l’objet mobile, des relations temporelles et spatiales dans notre ontologie. Nous avons évalué la complexité du mécanisme d’inférence et nous proposons des optimisations, comme l’utilisation d’un voisinage temporel et spatial. Nous proposons également une optimisation liée à notre application. Finalement, nous évaluons notre contribution et les résultats montrent l’impact positif de la réduction de la complexité du mécanisme d’inférence. Ces améliorations réduisent de moitié le temps de calcul et permettent de manipuler des données de plus grande dimensionSpatio-temporal data describing trajectories of moving objects has increased as a consequence of the larger availability of such data due to current sensors techniques. These devices use different technologies like global navigation satellite system (GNSS), wireless communication, radio-frequency identification (RFID), and sensors techniques. Although capturing technologies differ, the captured data has common spatial and temporal features. Thus, relational database management systems (RDBMS) can be used to store and query the captured data. RDBMS define spatial data types and spatial operations. Recent applications show that the solutions based on traditional data models are not sufficient to consider complex use cases that require advanced data models. A complex use case refers not only to data, but also to the domain expert knowledge and others. An inference mechanism enriches semantic trajectories with this knowledge. Temporal and spatial reasoning are fundamental for the inference mechanism on semantic trajectories. Several research fields are currently focusing on semantic trajectories to discover more information about mobile object behavior. In this thesis, we propose a modeling approach based on ontologies. We introduce a high-level trajectory ontology. The temporal and spatial parts form an implicit background of the trajectory model. So, we choose temporal and spatial models to be integrated with our trajectory model. We apply our modeling approach to a particular domain application : marine mammal trajectories. Therefore, we model this application and integrate it with our ontology. We implement our approach using RDF. Technically, we use Oracle Semantic Data Technologies. To accomplish reasoning over trajectories, we consider mobile objects, temporal and spatial knowledge in our ontology. Our approach demonstrates how temporal and spatial relationships that are common in natural language expressions (i.e., relations between time intervals like ”before”, ”after”, etc.) are represented in the ontology as user-defined rules. To annotate data with this kind of rules, we need an inference mechanism over trajectory ontology. Experiments over our model using the temporal and spatial reasoning address an inference computation complexity. This complexity is indicated in term of time computations and space storage. In order to reduce the inference complexity, we propose optimizations, such as domain constraints, temporal and spatial neighbor refinements. Moreover, controlling the repetition of the inference computation is also proposed. Even more, we define a refinement specifically for the application domain. Finally, we evaluate our contribution. Results show their positive impact on reducing the complexity of the inference mechanism. These refinements reduce half of the time computation and allow considering bigger size of the data
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Thomas, Owen M. « A temporal investigation into the dimensions of competitive anxiety : theory into practice ». Thesis, Sheffield Hallam University, 2004. http://shura.shu.ac.uk/20826/.
Texte intégralRésumé :
This thesis provided a detailed examination of psychological preparation during the time leading up to competition. Competitive anxiety symptoms were investigated through a fine-grained measurement approach incorporating the dimensions of intensity (i.e., level), directional perceptions (i.e., facilitative/debilitative), and frequency (i.e., amount of time) using the modified Competitive State Anxiety Inventory-2 (Jones & Swain, 1992; Swain &Jones, 1993). Three different research methodologies were employed across the thesis. The first two studies adopted a quantitative design. Study three used a mixed method design utilising an idiographic labelling approach and qualitative interview techniques. The final study utilised a single-subject multiple baseline design. Study one investigated intensity, direction and frequency dimensions of competitive state anxiety throughout a one week preparation period as a function of skill level in a sample of National and Club performers. Results indicated no skill level differences in the intensity or frequency of symptoms, but the national level performers were more facilitative in their interpretation of cognitive and somatic anxiety. Additionally, change-over-time effects were only noted in the intensity and frequency of symptoms, with greater variation being observed in the frequency dimension. Study two examined preparation based temporal variations in anxiety symptoms (intensity, direction and frequency) as a function of symptom interpretation (facilitative/debilitative/mixed). Results indicated facilitators displayed higher intensities of self-confidence, a more positive interpretation of cognitive and somatic anxiety, lower frequencies of cognitive anxiety and higher frequencies of self-confidence than the debilitators during the week leading up to competition. Further, change-over-time effects were observed in the dimensions of intensity, direction and frequency, with greater variation being noted in the frequency dimension. These findings highlighted important practical implications regarding the preparation strategies facilitators and debilitators used during the time leading up to competition. Study three addressed how the two groups of performers psychologically prepared during the time leading up to competition using qualitative interviews. Causal questions, and probes underpinned by an Experience Sampling Method technique followed by causal network analysis and composite sequence analysis revealed that in comparison to the debilitators, the facilitators utilised a refined psychological preparation routine during the time leading up to competition. This routine relied on specific imagery, thought rationalisation, cognitive restructuring, goal setting and self-talk skills during certain phases of the preparation period. These findings generated important practical implications when attempting to restructure performer's negative symptom experiences during preparation time for competition. The final study examined the influence of a multi-modal preparation based intervention programme on performers debilitated by their pre-performance anxiety symptoms. Intervention effects were examined over competitive sporting performance and the symptoms experienced during the preparation time for competition throughout a ten match competitive cycle. The intervention programme successfully restructured cognitive and somatic anxiety symptoms, increased self-confidence intensity, decreased cognitive anxiety frequency and increased self-confidence frequency throughout the preparation time for competition. Further, these changes were associated with an approximate 10% improvement in sporting performance. These findings indicated preparation based interventions provide beneficial effects for the performance of athletes, and the pre-event symptoms they experience. In summary, this thesis suggests sport psychologists, both researchers and practitioners, should consider the reactions to competition as preparation based temporal processes incorporating the dimensions of intensity, direction and frequency and develop interventions that are shaped by the time leading up to competition.
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Brynjarsdóttir, Jenný. « Dimension Reduced Modeling of Spatio-Temporal Processes with Applications to Statistical Downscaling ». The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1312935520.
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Luo, Weiqi. « Spatial/temporal modelling of crop disease data using high-dimensional regression ». Thesis, University of Leeds, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.493292.
Texte intégralRésumé :
Septoria tritici is one of the most serious foliar diseases of winter wheat across England and Wales, causing considerable reduction in yield quality and production. There are increasing pressures to control such a disease using disease forecasting systems sociated with various meteorological factors.
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Nerbonne, John A. « German temporal semantics three-dimensional tense logic and a GPSG fragment / ». New York : Garland Pub, 1985. http://books.google.com/books?id=pMRbAAAAMAAJ.
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Schuler, Keke. « Idiographic Temporal Dynamics of Posttraumatic Stress Disorder (PTSD) Symptom Dimensions in Daily Life ». Thesis, University of North Texas, 2017. https://digital.library.unt.edu/ark:/67531/metadc1062880/.
Texte intégralRésumé :
Understanding temporal relations among posttraumatic stress disorder (PTSD) symptom dimensions has received increasing attention in research. However, current findings in this area are limited by group-level approaches, which are based on inter-individual variation. PTSD is a heterogeneous syndrome and symptoms are likely to vary across individuals and time. Thus, it is important to examine temporal relations among PTSD symptom dimensions as dynamic processes and at the level of intra-individual variation. The aim of the present study was to capture temporal dynamics among PTSD symptom dimensions at an individual level using unified structural equation modeling (uSEM). World Trade Center (WTC) 9/11 responders (N = 202) oversampled for current PTSD (18.3% met criteria in past month) were recruited from the Long Island site of the WTC health program. Using ecological momentary assessment (EMA), PTSD symptoms were assessed three times a day over seven consecutive days. The person-specific temporal relations among PTSD symptom dimensions were estimated with individual-level uSEM. For the sample as a whole, hyperarousal played a key role in driving the other three symptom dimensions longitudinally, with the strongest effect in intrusive symptoms. However, daily temporal relations among PTSD symptoms were idiosyncratic. Although hyperarousal was a strong predictor of subsequent symptom severity, only 33.95% of the sample showed this predictive effect while others showed more evident temporal relations between intrusion and avoidance. Implications for personalized health care and recommendations for future research using individual-level uSEM in psychopathology are discussed.
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Goudou, Jean-François. « Apport de la dimension temporelle aux traitements de veille infrarouge marine ». Paris, ENST, 2007. http://www.theses.fr/2007ENST0035.
Texte intégralRésumé :
Un système de veille infrarouge marine a pour fonction de restituer de manière entièrement automatique à son opérateur un état des menaces potentielles dans un rayon d'une dizaine de kilomètres. La problématique de cette thèse est de mesurer l'apport d'un traitement spatio-temporel au niveau du module de détection. Les travaux de thèse sont constitués de trois volets. Le premier concerne l'apport de la dimension temporelle pour le blanchiment des séquences d'images, préalablement à la détection. Les contributions à ce domaine ont consisté d'une part en un état de l'at interdisciplinaire, d'autre part en l'adaptation puis l'évaluation pour cette aplication des algorithmes les plus prometteurs. Le second est l'étude des algorithmes d'estimation d'un champ dense de déplacement, afin de stabiliser la séquence d'images, puis d'estimer la présence de cibles par un critère cinématique par rapport à l'environnement. Néanmoins, les algorithmes classiques de ce domaine ne sont pas adaptés à un fond dont l'intensité fluctue très rapidement comme les fonds de mer. Le troisième volet est l'étude des algorithmes de super-résolution, qui sont une alternative à à la conception opto-électronique pour augmenter la résolution d'une image. La question fondamentale est le lien entre l'augmentation de la résolution et l'augmentation des performances. En particulier, la question du bruit en super-résolution est cruciale, et constitue une part importante du travail effectué durant cette thèseThe function of a navaI InfraRed Search and Track system is the fully automated display of the potential threats around the ship to the operator. The aim of this PhD thesis is the measurement of the interest of a spatio-temporal processing for the detection module. The work presented here consists in three parts. The first axis concerns the use of the temporal dimension for image sequences whitening, before the detection algorthm. The contributions in this field consist in an interdisciplinary state-of-the-art, followed by the adaptation and evaluation of the most promising algorithms. The second axis is the study of dense displacement field estimation algorithms, for the image sequence stabilization, then for the target detection, using a kinematic criterion. Unfortunately, the classical displacement estimation algorithms do not work properly for very quickly varying conditions like marine imagery. The third axis is the study of super-resolution algorithms, which are an alternative to opto-electronic conception for the inprovement of the device resolution. The fundamental question is the link between resolution increase and detection performances increase. Especially, the queston of noise in super-resolution is of utmost importance, and teherfore constitute a large part of the work presented here
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Huang, Lumeng. « Transport through Georeservoirs : Spatial Entropy in Hydraulic Properties, and Temporal Entropy in Residence Time Distributions ». Wright State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=wright1275920344.
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Abbod, T. H. « Developing a semantic integrity constraints system with temporal dimension to support a database ». Thesis, Open University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382588.
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Liu, Han. « Nonparametric Learning in High Dimensions ». Research Showcase @ CMU, 2010. http://repository.cmu.edu/dissertations/16.
Texte intégralRésumé :
This thesis develops flexible and principled nonparametric learning algorithms to explore, understand, and predict high dimensional and complex datasets. Such data appear frequently in modern scientific domains and lead to numerous important applications. For example, exploring high dimensional functional magnetic resonance imaging data helps us to better understand brain functionalities; inferring large-scale gene regulatory network is crucial for new drug design and development; detecting anomalies in high dimensional transaction databases is vital for corporate and government security.
Our main results include a rigorous theoretical framework and efficient nonparametric learning algorithms that exploit hidden structures to overcome the curse of dimensionality when analyzing massive high dimensional datasets. These algorithms have strong theoretical guarantees and provide high dimensional nonparametric recipes for many important learning tasks, ranging from unsupervised exploratory data analysis to supervised predictive modeling. In this thesis, we address three aspects:
1 Understanding the statistical theories of high dimensional nonparametric inference, including risk, estimation, and model selection consistency;
2 Designing new methods for different data-analysis tasks, including regression, classification, density estimation, graphical model learning, multi-task learning, spatial-temporal adaptive learning;
3 Demonstrating the usefulness of these methods in scientific applications, including functional genomics, cognitive neuroscience, and meteorology.
In the last part of this thesis, we also present the future vision of high dimensional and large-scale nonparametric inference.
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Guillet, Dominique. « Spatio-temporal image correlation spectroscopy : Extension to three dimensions and application to biological systems ». Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=110545.
Texte intégralRésumé :
The object of this thesis is to present work done using spatio-temporal image correlation spectroscopy (STICS), a technique that uses fluorescence intensity fluctuations in a microscopy image time series to calculate a complete space-time correlation function in order to measure transport dynamics in cells. The time evolution of this correlation function gives information on the magnitude and direction of a flow of fluorescent particles sampled in the image series. First, a new application of STICS to plant cell biology is shown. In dividing plant cells, delivery of new cell wall material to the forming cell plate requires intricate coordination of secretory vesicle trafficking and delivery. In this work, STICS is used to measure vesicle dynamics during plant cell division. It was discovered that vesicle transport to the plane of division occurs in three phases, each with its characteristic flow patterns and range of velocities, which directly reflect the rate of growth of the forming cell plate. The second part of this thesis presents the extension of the STICS technique to a third spatial dimension. The development of this new technique, called 3D STICS, allows the study of transport dynamics in three dimensions, which is more relevant in tissues and non adherent cells which are inherently 3D. Computer simulations were performed to test the accuracy and precision of the technique under a range of parameters such as particle density of immobile and moving populations; and number of images, velocity and resolution in the third spatial dimension. A comparison between values of velocities in a 2D plane recovered using STICS and its new 3D version is also presented.L'objet de cette thèse est de présenter des travaux faits à l'aide de la spectroscopie par corrélation spatiotemporelle d'images (STICS), une technique qui utilise les fluctuations d'intensité dans une série d'images capturées à l'aide d'un microscope par fluorescence pour calculer la fonction complète de corrélation spatiotemporelle, et ainsi mesurer la dynamique du transport de protéines à l'intérieur de cellules vivantes. L'évolution temporelle de cette fonction de corrélation donne de l'information sur la direction et la vitesse d'un flot de particules fluorescentes présentes dans la série d'images. Tout d'abord, une nouvelle application de la technique en biologie végétale est présentée. Lors de la division cellulaire végétale, le transport du matériel membranaire nécessaire à la formation de la plaque cellulaire requiert une grande précision dans la coordination du transport et de la livraison des vésicules de sécrétion. Dans cette thèse, STICS est utilisée pour mesurer la dynamique de ces vésicules pendant la division cellulaire végétale. Les résultats obtenus révèlent l'existence de trois phases dans le transport des vésicules de sécrétion au site de division cellulaire, chacune présentant une échelle de vitesse et des motifs de mouvement caractéristiques qui se reflètent dans le taux de croissance de la plaque cellulaire. Dans un deuxième temps, le développement de STICS pour inclure l'analyse de la troisième dimension spatiale est présenté. Cette nouvelle technique, appelée STICS 3D, permet l'étude de dynamiques en trois dimensions, ce qui est plus pertinent que la version deux-dimensionnelle pour les tissus et les cellules non adhérentes, qui ont un environnement intrinsèquement 3D. Des simulations par ordinateur ont été effectuées pour déterminer l'exactitude, la précision et les limites de la technique pour un éventail de paramètres comme la vitesse, le nombre d'images et la résolution dans la troisième dimension spatiale ainsi que la densité des populations immobiles et en mouvement. Une comparaison entre les résultats obtenus avec STICS et la nouvelle version 3D de la technique est également présentée.
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Mansfield, D. C. « Analysis of retinotectal regeneration in goldfish using polar dimensions : temporal sequence and spatial order ». Thesis, Open University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355992.
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Brown, Lyla J. P. « Scalar and temporal dimensions of partnership : education development and reform in the Eastern Caribbean ». Thesis, University of Bristol, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430194.
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Le, Duigou Sarah. « La dimension temporelle dans les modèles de recherche d'emploi : horizon, âge, expérience ». Phd thesis, Université du Maine, 2012. http://tel.archives-ouvertes.fr/tel-00770305.
Texte intégralRésumé :
Les modèles de recherche d'emploi sont aujourd'hui très largement utilisés en économie pour modéliser le marché du travail et évaluer les effets de certaines politiques publiques sur ce marché. Dans cette thèse, nous introduisons l'âge des travailleurs, dans ses deux dimensions, celle de l'expérience et celle de l'horizon social (âge de départ à la retraite), au sein d'un modèle de recherche d'emploi modélisant en même temps la distribution des salaires et les flux sur le marché du travail. Nous montrons que cette hétérogénéité affecte tous les comportements sur le marché du travail : la fixation de salaire, l'intensité de la recherche d'emploi et la productivité des appariements. Un tel modèle nous permet de décomposer la trajectoire salariale des travailleurs au cours de leur cycle de vie, en trois grands canaux : le jeu de salaire, l'accumulation du capital humain, et la présence d'institutions. Ce dernier canal explique notamment, par le biais des allocations chômage indexées sur le dernier salaire, la forte progression salariale associée à un faible taux de mobilité des travailleurs observé en France. Mais l'horizon peut aussi être technologique : la technologie d'une firme devient avec le temps obsolète. Dans ce cadre, nous montrons que la présence d'allocation chômage croissante avec l'ancienneté crée une distorsion croissante qui vient accélérer cette obsolescence. En vue d'atteindre l'optimum social, nous montrons qu'il est alors nécessaire d'introduire une taxe sur les licenciements, elle-même croissante.
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Le, Duigou Sarah. « La dimension temporelle dans les modèles de recherche d’emploi : horizon, âge, expérience ». Thesis, Le Mans, 2012. http://www.theses.fr/2012LEMA2004/document.
Texte intégralRésumé :
Les modèles de recherche d'emploi sont aujourd'hui très largement utilisés en économie pour modéliser le marché du travail et évaluer les effets de certaines politiques publiques sur ce marché. Dans cette thèse, nous introduisons l'âge des travailleurs, dans ses deux dimensions, celle de l'expérience et celle de l'horizon social (âge de départ à la retraite), au sein d'un modèle de recherche d'emploi modélisant en même temps la distribution des salaires et les flux sur le marché du travail. Nous montrons que cette hétérogénéité affecte tous les comportements sur le marché du travail : la fixation de salaire, l'intensité de la recherche d'emploi et la productivité des appariements. Un tel modèle nous permet de décomposer la trajectoire salariale des travailleurs au cours de leur cycle de vie, en trois grands canaux : le jeu de salaire, l'accumulation du capital humain, et la présence d'institutions. Ce dernier canal explique notamment, par le biais des allocations chômage indexées sur le dernier salaire, la forte progression salariale associée à un faible taux de mobilité des travailleurs observé en France. Mais l'horizon peut aussi être technologique : la technologie d'une firme devient avec le temps obsolète. Dans ce cadre, nous montrons que la présence d'allocation chômage croissante avec l'ancienneté crée une distorsion croissante qui vient accélérer cette obsolescence. En vue d'atteindre l'optimum social, nous montrons qu'il est alors nécessaire d'introduire une taxe sur les licenciements, elle-même croissanteIn economics, it is today usual to use search models to modelize labor market, and assess public policy on this market. In this thesis, we introduce the age heterogeneity of workers in a search model which takes into account both labor market flows and endogenous wage distribution. We show that this heterogeneity affects greatly agents' economic behaviors in terms of wage setting, search intensity, and matches' productivity, by its two dimensions, the workers' experience and the workers' horizon. This model allows us to decompose the wage trajectory of workers over their life cycle into three main channels : the wage game, the human capital accumulation and the presence of institutions. Besides, we show that this last channel, as composed of unemployment benefits indexed on workers' last wage, accounts for the simultaneous strong wage progression and weak workers' mobility observed in the French data. Yet, the horizon can also be technological : firms' embodied technology becomes obsolete with time. Given this technological horizon, the presence of tenure-growing unemployement benefits yields a distorsion which fastens obsolescence. In this context, only a tenure-growing firing tax allows the economy to reach its social optimum
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Zuur, Alain Francois. « Dimension reduction techniques in community ecology : with applications to spatio-temporal marine ecological data ». Thesis, University of Aberdeen, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287716.
Texte intégralRésumé :
The aim of this PhD-thesis is to develop techniques which can be used to analyse spatio-temporal ecological data sets. Central questions are: A. What are the relationships between species abundances and spatial environmental variables in a particular year? What are relationships between species? B. How do these species-environmental relations and species interactions change from year-to-year? What is the effect of global environmental variables on these year-to-year variations? The thesis is divided into two parts. In Part I, we concentrate on the first question. We discuss the state-of-the-art technique canonical correspondence analysis (CCA). Using assumptions which are unlikely to hold in practice, Ter Braak (1986) showed that CCA estimates certain parameters of the 'restricted Gaussian response (RGR) model'. This model describes species abundances as a unimodal, symmetric function along a gradient. The key feature in CCA and RGR is that the gradient is a linear combination of environmental variables. Using numerical optimisation routines, we show that the parameters of the RGR model can easily be estimated. This has considerable advantages over CCA, because all parameters are estimated in a regression context, without making doubtful assumptions. RGR is applied on various data sets. A model validation indicates that for some species the model is inappropriate. For this reason, we develop a smoothing model in which the covariate is a linear combination of environmental variables. It is called restricted generalised additive modelling (RGAM). In Part II, we concentrate on question B. We develop a new technique, called dynamic generalised additive modelling. For each species a smoothing function and a stochastic trend are estimated.
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Dou, Baojun. « Three essays on time series : spatio-temporal modelling, dimension reduction and change-point detection ». Thesis, London School of Economics and Political Science (University of London), 2015. http://etheses.lse.ac.uk/3242/.
Texte intégralRésumé :
Modelling high dimensional time series and non-stationary time series are two import aspects in time series analysis nowadays. The main objective of this thesis is to deal with these two problems. The first two parts deal with high dimensionality and the third part considers a change point detection problem. In the first part, we consider a class of spatio-temporal models which extend popular econometric spatial autoregressive panel data models by allowing the scalar coefficients for each location (or panel) different from each other. The model is of the following form: yt = D(λ0)Wyt + D(λ1)yt−1 + D(λ2)Wyt−1 + εt, (1) where yt = (y1,t, . . . , yp,t) T represents the observations from p locations at time t, D(λk) = diag(λk1, . . . , λkp) and λkj is the unknown coefficient parameter for the j-th location, and W is the p×p spatial weight matrix which measures the dependence among different locations. All the elements on the main diagonal of W are zero. It is a common practice in spatial econometrics to assume W known. For example, we may let wij = 1/(1 + dij ), for i ̸= j, where dij ≥ 0 is an appropriate distance between the i-th and the j-th location. It can simply be the geographical distance between the two locations or the distance reflecting the correlation or association between the variables at the two locations. In the above model, D(λ0) captures the pure spatial effect, D(λ1) captures the pure dynamic effect, and D(λ2) captures the time-lagged spatial effect. We also assume that the error term εt = (ε1,t, ε2,t, . . . , εp,t) T in (1) satisfies the condition Cov (yt−1, εt) = 0. When λk1 = · · · = λkp for all k = 1, 2, 3, (1) reduces to the model of Yu et al. (2008), in which there are only 3 unknown regressive coefficient parameters. In general the regression function in (1) contains 3p unknown parameters. To overcome the innate endogeneity, we propose a generalized Yule-Walker estimation method which applies the least squares estimation to a Yule-Walker equation. The asymptotic theory is developed under the setting that both the sample size and the number of locations (or panels) tend to infinity under a general setting for stationary and α-mixing processes, which includes spatial autoregressive panel data models driven by i.i.d. innovations as special cases. The proposed methods are illustrated using both simulated and real data. In part 2, we consider a multivariate time series model which decomposes a vector process into a latent factor process and a white noise process. Let yt = (y1,t, · · · , yp,t) T be an observable p × 1 vector time series process. The factor model decomposes yt in the following form: yt = Axt + εt , (2) where xt = (x1,t, · · · , xr,t) T is a r × 1 latent factor time series with unknown r ≤ p and A = (a1, a2, · · · , ar) is a p × r unknown constant matrix. εt is a white noise process with mean 0 and covariance matrix Σε. The first part of (2) is a dynamic part and the serial dependence of yt is driven by xt. We will achieve dimension reduction once r ≪ p in the sense that the dynamics of yt is driven by a much lower dimensional process xt. Motivated by practical needs and the characteristic of high dimensional data, the sparsity assumption on factor loading matrix is imposed. Different from Lam, Yao and Bathia (2011)’s method, which is equivalent to an eigenanalysis of a non negative definite matrix, we add a constraint to control the number of nonzero elements in each column of the factor loading matrix. Our proposed sparse estimator is then the solution of a constrained optimization problem. The asymptotic theory is developed under the setting that both the sample size and the dimensionality tend to infinity. When the common factor is weak in the sense that δ > 1/2 in Lam, Yao and Bathia (2011)’s paper, the new sparse estimator may have a faster convergence rate. Numerically, we employ the generalized deflation method (Mackey (2009)) and the GSLDA method (Moghaddam et al. (2006)) to approximate the estimator. The tuning parameter is chosen by cross validation. The proposed method is illustrated with both simulated and real data examples. The third part is a change point detection problem. we consider the following covariance structural break detection problem: Cov(yt)I(tj−1 ≤ t < tj ) = Σtj−1, j = 1, · · · , m + 1, where yt is a p × 1 vector time series, Σtj−1̸ = Σtj and {t1, . . ., tm} are change points, 1 = t0 < t1 < · · · < tm+1 = n. In the literature, the number of change points m is usually assumed to be known and small, because a large m would involve a huge amount of computational burden for parameters estimation. By reformulating the problem in a variable selection context, the group least absolute shrinkage and selection operator (LASSO) is proposed to estimate m and the locations of the change points {t1, . . ., tm}. Our method is model free, it can be extensively applied to multivariate time series, such as GARCH and stochastic volatility models. It is shown that both m and the locations of the change points {t1, . . . , tm} can be consistently estimated from the data, and the computation can be efficiently performed. An improved practical version that incorporates group LASSO and the stepwise regression variable selection technique are discussed. Simulation studies are conducted to assess the finite sample performance.
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Le, Hai Ha. « Spatio-temporal information system for the geosciences ». Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2014. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-154510.
Texte intégralRésumé :
The development of spatio–temporal geoscience information systems (TGSIS) as the next generation of geographic information systems (GIS) and geoscience information systems (GSIS) was investigated with respect to the following four aspects: concepts, data models, software, and applications. These systems are capable of capturing, storing, managing, and querying data of geo–objects subject to dynamic processes, thereby causing the evolution of their geometry, topology and geoscience properties. In this study, five data models were proposed. The first data model represents static geo–objects whose geometries are in the 3–dimensional space. The second and third data models represent geological surfaces evolving in a discrete and continuous manner, respectively. The fourth data model is a general model that represents geo–objects whose geometries are n–dimensional embedding in the m–dimensional space R^m, m >= 3. The topology and the properties of these geo–objects are also represented in the data model. In this model, time is represented as one dimension (valid time). Moreover, the valid time is an independent variable, whereas geometry, topology, and the properties are dependent (on time) variables. The fifth data model represents multiple indexed geoscience data in which time and other non–spatial dimensions are interpreted as larger spatial dimensions.
To capture data in space and time, morphological interpolation methods were reviewed, and a new morphological interpolation method was proposed to model geological surfaces evolving continuously in a time interval. This algorithm is based on parameterisation techniques to locate the cross–reference and then compute the trajectories complying with geometrical constraints. In addition, the long transaction feature was studied, and the data schema, functions, triggers, and views were proposed to implement the long transaction feature and the database versioning in PostgreSQL. To implement database versioning tailored to geoscience applications, an algorithm comparing two triangulated meshes was also proposed. Therefore, TGSIS enable geologists to manage different versions of geoscience data for different geological paradigms, data, and authors.
Finally, a prototype software system was built. This system uses the client/server architecture in which the server side uses the PostgreSQL database management system and the client side uses the gOcad geomodeling system. The system was also applied to certain sample applications.
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Schubert, Erich. « Generalized and efficient outlier detection for spatial, temporal, and high-dimensional data mining ». Diss., Ludwig-Maximilians-Universität München, 2013. http://nbn-resolving.de/urn:nbn:de:bvb:19-166938.
Texte intégralRésumé :
Knowledge Discovery in Databases (KDD) ist der Prozess, nicht-triviale Muster aus großen Datenbanken zu extrahieren, mit dem Ziel, dass diese bisher unbekannt, potentiell nützlich, statistisch fundiert und verständlich sind. Der Prozess umfasst mehrere Schritte wie die Selektion, Vorverarbeitung, Evaluierung und den Analyseschritt, der als Data-Mining bekannt ist. Eine der zentralen Aufgabenstellungen im Data-Mining ist die Ausreißererkennung, das Identifizieren von Beobachtungen, die ungewöhnlich sind und mit der Mehrzahl der Daten inkonsistent erscheinen. Solche seltene Beobachtungen können verschiedene Ursachen haben:
Messfehler, ungewöhnlich starke (aber dennoch genuine) Abweichungen, beschädigte oder auch manipulierte Daten. In den letzten Jahren wurden zahlreiche Verfahren zur Erkennung von Ausreißern vorgeschlagen, die sich oft nur geringfügig zu unterscheiden scheinen, aber in den Publikationen experimental als ``klar besser'' dargestellt sind. Ein Schwerpunkt dieser Arbeit ist es, die unterschiedlichen Verfahren zusammenzuführen und in einem gemeinsamen Formalismus zu modularisieren. Damit wird einerseits die Analyse der Unterschiede vereinfacht, andererseits aber die Flexibilität der Verfahren erhöht, indem man Module hinzufügen oder ersetzen und damit die Methode an geänderte Anforderungen und Datentypen anpassen kann.
Um die Vorteile der modularisierten Struktur zu zeigen, werden
(i) zahlreiche bestehende Algorithmen in dem Schema formalisiert,
(ii) neue Module hinzugefügt, um die Robustheit, Effizienz, statistische Aussagekraft und Nutzbarkeit der Bewertungsfunktionen zu verbessern, mit denen die existierenden Methoden kombiniert werden können,
(iii) Module modifiziert, um bestehende und neue Algorithmen auf andere, oft komplexere, Datentypen anzuwenden wie geographisch annotierte Daten, Zeitreihen und hochdimensionale Räume,
(iv) mehrere Methoden in ein Verfahren kombiniert, um bessere Ergebnisse zu erzielen,
(v) die Skalierbarkeit auf große Datenmengen durch approximative oder exakte Indizierung verbessert.
Ausgangspunkt der Arbeit ist der Algorithmus Local Outlier Factor (LOF). Er wird zunächst mit kleinen Erweiterungen modifiziert, um die Robustheit und die Nutzbarkeit der Bewertung zu verbessern. Diese Methoden werden anschließend in einem gemeinsamen Rahmen zur Erkennung lokaler Ausreißer formalisiert, um die entsprechenden Vorteile auch in anderen Algorithmen nutzen zu können. Durch Abstraktion von einem einzelnen Vektorraum zu allgemeinen Datentypen können auch räumliche und zeitliche Beziehungen analysiert werden. Die Verwendung von Unterraum- und Korrelations-basierten Nachbarschaften ermöglicht dann, einen neue Arten von Ausreißern in beliebig orientierten Projektionen zu erkennen. Verbesserungen bei den Bewertungsfunktionen erlauben es, die Bewertung mit der statistischen Intuition einer Wahrscheinlichkeit zu interpretieren und nicht nur eine Ausreißer-Rangfolge zu erstellen wie zuvor. Verbesserte Modelle generieren auch Erklärungen, warum ein Objekt als Ausreißer bewertet wurde.
Anschließend werden für verschiedene Module Verbesserungen eingeführt, die unter anderem ermöglichen, die Algorithmen auf wesentlich größere Datensätze anzuwenden -- in annähernd linearer statt in quadratischer Zeit --, indem man approximative Nachbarschaften bei geringem Verlust an Präzision und Effektivität erlaubt. Des weiteren wird gezeigt, wie mehrere solcher Algorithmen mit unterschiedlichen Intuitionen gleichzeitig benutzt und die Ergebnisse in einer Methode kombiniert werden können, die dadurch unterschiedliche Arten von Ausreißern erkennen kann.
Schließlich werden für reale Datensätze neue Ausreißeralgorithmen konstruiert, die auf das spezifische Problem angepasst sind. Diese neuen Methoden erlauben es, so aufschlussreiche Ergebnisse zu erhalten, die mit den bestehenden Methoden nicht erreicht werden konnten. Da sie aus den Bausteinen der modularen Struktur entwickelt wurden, ist ein direkter Bezug zu den früheren Ansätzen gegeben. Durch Verwendung der Indexstrukturen können die Algorithmen selbst auf großen Datensätzen effizient ausgeführt werden.Knowledge Discovery in Databases (KDD) is the process of extracting non-trivial patterns in large data bases, with the focus of extracting novel, potentially useful, statistically valid and understandable patterns. The process involves multiple phases including selection, preprocessing, evaluation and the analysis step which is known as Data Mining. One of the key techniques of Data Mining is outlier detection, that is the identification of observations that are unusual and seemingly inconsistent with the majority of the data set. Such rare observations can have various reasons: they can be measurement errors, unusually extreme (but valid) measurements, data corruption or even manipulated data. Over the previous years, various outlier detection algorithms have been proposed that often appear to be only slightly different than previous but ``clearly outperform'' the others in the experiments. A key focus of this thesis is to unify and modularize the various approaches into a common formalism to make the analysis of the actual differences easier, but at the same time increase the flexibility of the approaches by allowing the addition and replacement of modules to adapt the methods to different requirements and data types. To show the benefits of the modularized structure, (i) several existing algorithms are formalized within the new framework (ii) new modules are added that improve the robustness, efficiency, statistical validity and score usability and that can be combined with existing methods (iii) modules are modified to allow existing and new algorithms to run on other, often more complex data types including spatial, temporal and high-dimensional data spaces (iv) the combination of multiple algorithm instances into an ensemble method is discussed (v) the scalability to large data sets is improved using approximate as well as exact indexing. The starting point is the Local Outlier Factor (LOF) algorithm, which is extended with slight modifications to increase robustness and the usability of the produced scores. In order to get the same benefits for other methods, these methods are abstracted to a general framework for local outlier detection. By abstracting from a single vector space, other data types that involve spatial and temporal relationships can be analyzed. The use of subspace and correlation neighborhoods allows the algorithms to detect new kinds of outliers in arbitrarily oriented subspaces. Improvements in the score normalization bring back a statistic intuition of probabilities to the outlier scores that previously were only useful for ranking objects, while improved models also offer explanations of why an object was considered to be an outlier. Subsequently, for different modules found in the framework improved modules are presented that for example allow to run the same algorithms on significantly larger data sets -- in approximately linear complexity instead of quadratic complexity -- by accepting approximated neighborhoods at little loss in precision and effectiveness. Additionally, multiple algorithms with different intuitions can be run at the same time, and the results combined into an ensemble method that is able to detect outliers of different types. Finally, new outlier detection methods are constructed; customized for the specific problems of these real data sets. The new methods allow to obtain insightful results that could not be obtained with the existing methods. Since being constructed from the same building blocks, there however exists a strong and explicit connection to the previous approaches, and by using the indexing strategies introduced earlier, the algorithms can be executed efficiently even on large data sets.
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Antunes, Dante Carlos. « Modelagem temporal de sistemas : uma abordagem fundamentada em redes de petri ». reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 1997. http://hdl.handle.net/10183/21112.
Texte intégralRésumé :
Neste trabalho e proposta a abordagem TempER-Tr, uma técnica de modelagem conceitual, fundamentada em rede de Petri, que integra a especificação das propriedades dinâmicas de um sistema a um modelo de dados temporal do tipo entidade relacionamento. Um modelo ou esquema conceitual descreve as propriedades identificadas de um sistema a ser desenvolvido. Estas propriedades podem ser classificadas em propriedades estáticas e propriedades dinâmicas As propriedades estáticas descrevem os estados que o sistema pode alcançar, enquanto que as propriedades dinâmicas descrevem as transições entre estes estados. A modelagem conceitual das propriedades estáticas é normalmente conhecida como modelagem de dados. A modelagem das propriedades dinâmicas é denominada de modelagem funcional ou comportamental. Mais especificamente, o modelo TempER-Tr é uma extensão de um trabalho anterior, conhecido como ER-Tr. No modelo ER-Tr, para descrever as propriedades estáticas de um sistema utiliza-se o modelo entidade-relacionamento convencional. No modelo TempER-Tr passa-se a adotar um modelo entidade-relacionamento temporal. Aliado a isto, uma nova linguagem de anotação, baseada em SQL, com mais poder de expressão é proposta. O modelo entidade-relacionamento convencional não possui dispositivos de modelagem capazes de especificar restrições que envolvam a associação dos objetos com o tempo, exigindo que isto se faca ao nível da modelagem das propriedades dinâmicas. Em um modelo entidade-relacionamento convencional, os conjuntos de entidades e relacionamentos apresentam apenas duas dimensões: a primeira refere-se as instâncias (linhas) e a segunda aos atributos (colunas). Em uma abordagem entidade relacionamento temporal, uma nova dimensão e acrescentada: o eixo temporal, possibilitando que as restrições temporais decorrentes da associação entre os objetos possam ser especificadas ao nível do modelo estático. Um requisito importante a ser preenchido por um modelo de dados temporal é permitir que em um mesmo diagrama seja possível associar objetos (entidades, relacionamentos ou atributos) temporalizados com objetos não temporalizados. lsto porque em sistemas de informação alguns dados precisam ser explicitamente referenciados ao tempo e outros não, ou porque não mudam com o tempo, ou porque é irrelevante ao usuário saber quando os fatos ocorreram. O modelo de dados temporal proposto neste trabalho, denominado TempER, pressupõe que todas as entidades, sejam elas temporalizadas ou não temporalizadas, apresentam uma "existência", ou seja, uma validade temporal. No caso das entidades temporalizadas esta existência é um subconjunto de pontos do eixo temporal. Em virtude disto são chamadas de entidades transitórias. Em relação as entidades não temporalizadas, e assumido que "existem sempre", ou seja, a sua validade temporal é constante, implícita e igual a todo o eixo temporal. Por isto são denominadas entidades perenes. Tanto as entidades transitórias quanto as entidades perenes, são focalizadas pelo modelo TempER através de duas perspectivas: uma intemporal e outra temporal. Através da perspectiva intemporal as entidades apresentam duas dimensões, semelhança do que ocorre em um modelo entidade-relacionamento convencional. Através da perspectiva temporal as entidades apresentam três dimensões, as duas convencionais e mais o tempo. Enquanto que o modelo de dados temporal descreve as propriedades estáticas de um sistema, o modelo comportamental, a outra face da abordagem TempER-Tr, focaliza as transações executadas no interior do sistema, em resposta a eventos que ocorrem no ambiente externo. Estas transações, quando efetivadas, provocam mudanças de estados no sistema. Entretanto, para estarem habilitadas a ocorrer, é necessário que um determinado conjunto de restrições dinâmicas sejam atendidas, o que se configura em um comportamento análogo ao de uma rede de Petri. O modelo TempER-Tr é completamente mapeável, inclusive o modelo de dados temporal, para a rede CEM, um tipo de rede de Petri de alto nível. Isto permite que a sua semântica seja formalmente especificada e possibilita o aproveitamento das características das redes de Petri.This dissertation presents TempER-Tr approach. TempER-Tr is a conceptual modeling technique based on Petri nets that integrates the specification of the dynamic properties of system to a temporal entity-relationship data model. A model or conceptual schema describes the identified properties of a system. These properties can be classified into static and dynamic properties. The static properties describe the states that the system can reach, while the dynamic properties describe the transitions between the states. The conceptual modeling of the static properties is usually known as data modeling, while behavioral or functional modeling deals with dynamic properties. The TempER-Tr model is an extension of a model known as ER-Tr. In the ER-Tr model, the conventional entity-relationship model is used to describe the static properties of a system. In the TempER-Tr model, it is adopted a kind of temporal entityrelationship model. In addition, a new notation language is proposed, based on SQL, with more expression power. The conventional entity-relationship model doesn't provide tools to specify constraints that involve the association of objects with the time dimension, requiring that this have to be done at the dynamic properties modeling level. At the conventional entityrelationship model the entities and relationships sets present just two dimensions: the first one is related to the instance (lines) and the second to the attributes (columns). At a temporal entity-relationship approach, a new dimension is added: the time line. This way, the temporal constraints can be specified at the level of the static diagrams. An important requirement to be supplied by any temporal data model is the possibility to relate, into the same diagram, time-varying objects with time-invarying objects. This is due to the fact that in information systems some data need to be explicitly related to time and others don't, either because they don't change with time, or because users don't need to know when the facts occurred. • The temporal data model proposed in this work, nominated TempER, presupposes that all entities, being them time-varying or time-invarying, have an "existence", or a temporal validity. At the time-varying entities, named transitory entities, this existence is a subset of points from the time line. In time-invarying entities, named perennial entities, it is assumed that they "always exist", i.e., their temporal validity is constant, implicit, and equal to all points of the time line. Transitory entities, as much as perennial entities, are focused by the TempER model through two perspectives: a temporal perspective and a non-temporal perspective. Through the non-temporal perspective the entities present two dimensions - lines and columns - similar to a conventional entity-relationship model. Through the temporal perspective the entities present three dimensions: the two conventional dimensions and, in addition, the time dimension. While the temporal data model describes the static properties of a system, the behavioral model in the TempER-Tr approach focus the transactions that are executed by the system, in response to the events that occur at the external environment. A certain set of dynamic constraints must be attended so that transactions are enable to occur. This configures a behavior similar to a Petri net. The TempER-Tr model is completely mappeable, inclusive the temporal data model, to the CEM net, a kind of high level Petri net. This way, the semantic of TempER-Tr model is formally specified. In addition, the utilization of the characteristics of Petri nets is possible.
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Martin, Steven. « Maîtrise de la dimension temporelle de la qualité de service dans les réseaux ». Paris 12, 2004. https://athena.u-pec.fr/primo-explore/search?query=any,exact,990002150280204611&vid=upec.
Texte intégralRésumé :
Les nouvelles applications sur Internet nécessitent des garanties de qualité de service (QoS) de la part du réseau. Nous nous intéressons à deux paramètres de QoS : le temps de réponse et la gigue de bout-en-bout. Nous proposons un ordonnancement, noté FP/DP, à base de priorités fixes (FP), départageant les paquets ex aequo selon leurs priorités dynamiques (DP). La priorité fixe d'un flux reflète son degré d'importance et sa priorité dynamique est un paramètre temporel. FP/FIFO et FP/EDF sont deux exemples d'ordonnancement FP/DP. Nous déterminons des bornes déterministes sur les paramètres de QoS considérés, en utilisant l'approche par trajectoire. En monoprocesseur, nous améliorons les résultats existants et prouvons que FP/EDF domine FP/FIFO sous certaines conditions. En distribué, nous apportons de nouveaux résultats et montrons que l'approche par trajectoire est beaucoup moins pessimiste que l'approche holistique. Nos résultats sont appliqués dans une architecture DiffServ/MPLSNew applications in the Internet need, from the network, quality of service (QoS) guarantees. We focus on two QoS parameters : the end-to-end response time and jitter. We propose a scheduling algorithm, denoted FP/DP, based on fixed priorities (FP), where packets sharing the same fixed priority are processed according to their dynamic priorities. The fixed priority of a flow matches its importance degree and its dynamic priority is a time parameter. FP/FIFO and FP/EDF are two examples of FP/DP scheduling. We determine deterministic bounds on the Q0S parameters considered, using the trajectory approach. For the uniprocessor case, we improve the existing results and prove that FP/EDF dominates FP/FIFO under some conditions. For the distributed case, we establish new results and show that the trajectory approach s less pessimistic than the holistic one. Our results are applied in a DiffServ/MPLS architecture
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Martin, Steven Minet Pascale George Laurent. « Maîtrise de la dimension temporelle de la qualité de service dans les réseaux ». Créteil : Université de Paris-Val-de-Marne, 2004. http://doxa.scd.univ-paris12.fr:80/theses/th0215028.pdf.
Texte intégral
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MARTIN, Steven. « Maîtrise de la dimension temporelle de la qualité de service dans les réseaux ». Phd thesis, Université Paris XII Val de Marne, 2004. http://tel.archives-ouvertes.fr/tel-00007638.
Texte intégralRésumé :
Les nouvelles applications sur Internet nécessitent des garanties de qualité de service (QoS) de la part du réseau. Nous nous intéressons à deux paramètres de QoS : le temps de réponse et la gigue de bout-en-bout. Nous proposons un ordonnancement, noté FP/DP, à base de priorités fixes (FP), départageant les paquets ex aequo selon leurs priorités dynamiques (DP). La priorité fixe d'un flux reflète son degré d'importance et sa priorité dynamique est un paramètre temporel. FP/FIFO et FP/EDF sont deux exemples d'ordonnancement FP/DP. Nous déterminons des bornes déterministes sur les paramètres de QoS considérés, en utilisant l'approche par trajectoire. En monoprocesseur, nous améliorons les résultats existants et prouvons que FP/EDF domine FP/FIFO sous certaines conditions. En distribué, nous apportons de nouveaux résultats et montrons que l'approche par trajectoire est beaucoup moins pessimiste que l'approche holistique. Nos résultats sont appliqués dans une architecture DiffServ/MPLS.
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Pereira, Gustavo Marttos Cáceres. « Modelo de recuperação de informação com suporte semântico e temporal / ». Marília, 2020. http://hdl.handle.net/11449/192964.
Texte intégralRésumé :
Orientador: Leonardo Castro BotegaResumo: No contexto de gerenciamento de emergências, onde as informações são provenientes de fontes heterogêneas, é necessário que as tomadas de decisões sejam assertivas e dentro de um intervalo de tempo hábil. O tempo possui grande relevância por ser fundamental no domínio deste contexto, pois é criando uma linha do tempo, ou seja, ao decorrer dele, que se torna viável a percepção e compreensão de todas as características de uma situação, além de possibilitar a melhoria da qualidade da informação, a qual torna-se imprescindível no contexto de gerenciamento de emergências, considerando a complexidade e dinamicidade dos dados. Este trabalho objetiva a melhoria dos processos informacionais da recuperação da informação por meio da criação de um modelo com suporte semântico e temporal para que seja possível atender tais requisitos. A natureza deste trabalho é qualitativa, de finalidade teórico-aplicada e de tipo exploratória, sua metodologia conta com uma prova de conceito envolvendo situações de emergências de incêndio, na qual foi possível avaliar o comportamento da qualidade informação e inferir novos conhecimentos temporais que poderão servir de insumos para tomadas de decisões mais assertivas.
Abstract: In the context of emergency management, where information comes from heterogeneous sources, decision-making must be assertive and within a timely interval. Time has great relevance because it is fundamental in the domain of this context, because it is creating a timeline, that is, in the course of it, that it becomes feasible to perceive and understand all the characteristics of a situation, besides enabling the improvement of quality of information, which becomes indispensable in the context of emergency management, considering the complexity and dynamicity of the data. This work aims to improve the informational processes of information retrieval through the creation of a model with semantic and temporal support so that it is possible to meet these requirements. The nature of this work is qualitative, of theoretical-applied purpose and exploratory type, its methodology has a proof of concept involving situations of fire emergencies, in which it was possible to evaluate the behavior of quality information and infer new temporal knowledge that may serve as inputs for making more assertive decisions.
Mestre
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Iacopini, Matteo. « Essays on econometric modelling of temporal networks ». Thesis, Paris 1, 2018. http://www.theses.fr/2018PA01E058/document.
Texte intégralRésumé :
La théorie des graphes a longtemps été étudiée en mathématiques et en probabilité en tant qu’outil pour décrire la dépendance entre les nœuds. Cependant, ce n’est que récemment qu’elle a été mise en œuvre sur des données, donnant naissance à l’analyse statistique des réseaux réels.La topologie des réseaux économiques et financiers est remarquablement complexe: elle n’est généralement pas observée, et elle nécessite ainsi des procédures inférentielles adéquates pour son estimation, d’ailleurs non seulement les nœuds, mais la structure de la dépendance elle-même évolue dans le temps. Des outils statistiques et économétriques pour modéliser la dynamique de changement de la structure du réseau font défaut, malgré leurs besoins croissants dans plusieurs domaines de recherche. En même temps, avec le début de l’ère des “Big data”, la taille des ensembles de données disponibles devient de plus en plus élevée et leur structure interne devient de plus en plus complexe, entravant les processus inférentiels traditionnels dans plusieurs cas. Cette thèse a pour but de contribuer à ce nouveau champ littéraire qui associe probabilités, économie, physique et sociologie en proposant de nouvelles méthodologies statistiques et économétriques pour l’étude de l’évolution temporelle des structures en réseau de moyenne et haute dimensionGraph theory has long been studied in mathematics and probability as a tool for describing dependence between nodes. However, only recently it has been implemented on data, giving birth to the statistical analysis of real networks.The topology of economic and financial networks is remarkably complex: it is generally unobserved, thus requiring adequate inferential procedures for it estimation, moreover not only the nodes, but the structure of dependence itself evolves over time. Statistical and econometric tools for modelling the dynamics of change of the network structure are lacking, despite their increasing requirement in several fields of research. At the same time, with the beginning of the era of “Big data” the size of available datasets is becoming increasingly high and their internal structure is growing in complexity, hampering traditional inferential processes in multiple cases.This thesis aims at contributing to this newborn field of literature which joins probability, economics, physics and sociology by proposing novel statistical and econometric methodologies for the study of the temporal evolution of network structures of medium-high dimension
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Talha, Tariq. « A numerical investigation of three-dimensional unsteady turbulent channel flow subjected to temporal acceleration ». Thesis, University of Warwick, 2012. http://wrap.warwick.ac.uk/47055/.
Texte intégralRésumé :
Investigation of turbulence response during constant temporal acceleration and deceleration can assist in improving the understanding of turbulence evolution and flow physics. Such flows have potential importance in engineering applications for example the air flow through the main trachea during the breathing cycle experience temporal acceleration and deceleration. The previous experimental and theoretical investigations based on conventional computational fluid dynamics (CFD) modelling could not provide the detailed information about turbulence response in the near-wall region in such types of flows. In particular, the response of near-wall structures has not been studied for turbulent flow with temporal acceleration and deceleration. In the present study, turbulent flows involving temporal acceleration and deceleration has been investigated using DNS and LES. A fully implicit fractional step method is implemented in the present study. The Navier-Stokes equations are discretised using finite volume method. Second-order- implicit Crank-Nicolson method is used for temporal discretisation for the convective and viscous terms. Second-order accuracy of spatial discretisation is achieved using four neighbouring points to calculate velocity gradients. A uniform grid is used in the streamwise and spanwise directions while a non-uniform grid is employed in the wall-normal direction. The numerical implementation has been validated for three test cases. The dynamic subgrid-scale model has been implemented for LES calculations. The LES model implementation has been validated through comparison with benchmark data available in literature. As one of the first DNS of accelerating turbulent flow, this study has produced a comprehensive database of turbulent statistics which can be used for unsteady turbulence modelling and validation. The detailed investigation has substantially enhanced the understanding of turbulence response for such flows. The flow physics has been studied in detail using turbulent kinetic energy budget analysis, vorticity analysis, anisotropy invariant maps and energy spectra. The evolution of new turbulent structures during the acceleration has been investigated using low-speed streaks and λ2 plots and many interesting ow characteristics have been found. The effect of different acceleration rates has been studied using LES. The turbulence propaga- tion in the core region has been studied for different acceleration rates. Turbulent flow subjected to constant temporal deceleration has also been investigated using LES. The effect of different deceleration rates has been also studied. The turbulent flow response to temporal deceleration has been analysed using the rms velocity and vorticity, kinetic energy budget and Reynolds stress anisotropy tensor analysis.
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Murcia, Jérôme de. « Reconstruction d'images cardiaques en tomographie d'émission monophotonique à l'aide de modèles spatio-temporels ». Grenoble INPG, 1996. http://www.theses.fr/1996INPG0078.
Texte intégralRésumé :
La tomographie d'emission monophotonique fournit une sequence d'images 3d representatives de la distribution du traceur administre au patient, pour differents instants du cycle cardiaque. Elle met en evidence les zones mal irriguees du myocarde. Afin d'eviter une trop longue immobilisation, les temps d'acquisition sont limites, ce qui conduit a des mesures tres bruitees. La reconstruction etant un probleme inverse mal-pose, les images tomographiques sont alors tres degradees. Nous proposons dans cette these deux methodes permettant d'ameliorer la qualite statistique de ces images en regularisant temporellement le processus de reconstruction. La simple moyenne temporelle conduisant a un flou cinetique, le mouvement du myocarde est d'abord estime a partir du suivi de trois surfaces caracteristiques du myocarde, puis integre dans l'algorithme de reconstruction. La premiere methode developpee consiste a reconstruire une phase particuliere connaissant l'ensemble des mesures acquises et la loi d'evolution. La reconstruction s'inscrit dans le cadre theorique du filtrage de kalman. La solution formelle necessitant l'inversion d'une matrice de tres grande dimension, nous proposons une solution sous-optimale mais rapide. L'algorithme recursif repose sur des operations de type filtrage-retropropjection. Nous presentons ensuite une deuxieme approche dans laquelle l'ensemble des phases est reconstruite simultanement. La reconstruction de la sequence est effectuee par minimisation d'une fonction quadratique etablie dans le cadre d'une regularisation spatio-temporelle. Le calcul iteratif des images est effectue a partir de l'algorithme du gradient conjugue. Les resultats experimentaux montrent la validite de notre approche et mettent en evidence l'apport d'une regularisation temporelle
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Remou, Charaf. « Identification et dimension spatio-temporelle des conflits territoriaux dans les projets d'aménagement à Mayotte ». Thesis, Tours, 2017. http://www.theses.fr/2017TOUR1501/document.
Texte intégralRésumé :
L’île de Mayotte, un bout de France dans l’océan Indien entre Madagascar et l’Afrique de l’est, est un territoire insuffisamment équipé. Elle a longtemps été victime dans son développement spatial et socio-économique, d’une succession de statuts juridiques jamais stables, ne favorisant pas une politique de développement et d’aménagement. Mais depuis le changement de statut de l’île en collectivité départementale en 2001 (101 ème département français en 2011), Mayotte a entamé sa phase de mutation. Ainsi, le nouvel objectif de l’ile est de rattraper son retard par rapport à la Métropole et aux autres Départements d’Outre-Mer (DOM). Mais ici, plus qu’ailleurs, les projets d’aménagement sont sources de tensions du fait d’une conjonction de nombreux facteurs parmi lesquels le statut du foncier régi par deux juridictions, d’une part, coutumière et d’autre part le droit commun françaisThe island of Mayotte, a piece of France in the Indian Ocean between Madagascar and East Africa, is an insufficiently equipped territory. It was the victim of a succession of never stable legal status, not promoting a policy of planning. But since the change of status of the island in to a departmental authority in 2001 (101 th French department in 2011), Mayotte begain its mutation. Thus, the new goal of the island is to catch up with the metropolis and other Overseas Departments (DOM). But here, more than elsewhere, development projects are a source of tension due to a combination of many factors, including the status of land governed by two jurisdictions, the customary on the one hand, and the French law on the other hand
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Sadek, Nabel. « Comparison of Two Vortex-in-cell Schemes Implemented to a Three-dimensional Temporal Mixing Layer ». Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/23198.
Texte intégralRésumé :
Numerical simulations are presented for three dimensional viscous incompressible free shear flows. The numerical method is based on solving the vorticity equation using Vortex-In-Cell method. In this method, the vorticity field is discretized into a finite set of Lagrangian elements (particles) and the computational domain is covered by Eulerian mesh. Velocity field is computed on the mesh by solving Poisson equation. The solution proceeds in time by advecting the particles with the flow. Second order Adam-Bashford method is used for time integration. Exchange of information between Lagrangian particles and Eulerian grid is carried out using the M’4 interpolation scheme. The classical inviscid scheme is enhanced to account for stretching and viscous effects. For that matter, two schemes are used. The first one used periodic remeshing of the vortex particles along with fourth order finite difference approximation for the partial derivatives of the stretching and viscous terms. In the second scheme, derivatives are approximated by least squares polynomial. The novelty of this work is signified by using the moving least squares technique within the framework of the Vortex-in-Cell method and implementing it to a three dimensional temporal mixing layer. Comparisons of the mean flow and velocity statistics are made with experimental studies. The results confirm the validity of the present schemes. Both schemes also demonstrate capability to qualitatively capture significant flow scales, and allow gaining physical insight as to the development of instabilities and the formation of three dimensional vortex structures. The two schemes show acceptable low numerical diffusion as well.
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Fontes, Nuno Ricardo Moura. « Sistemas dinâmicos, análise numérica de séries temporais e aplicações às finanças ». Master's thesis, Instituto Superior de Economia e Gestão, 2013. http://hdl.handle.net/10400.5/6454.
Texte intégralRésumé :
Mestrado em Matemática FinanceiraTaken's theorem (1981) shows how the series of measurements from a given system can be used to reconstruct the original system's underlying dynamic process. In this work we start from this point and build a bridge between theoretical results and its practical application. Several algorithms are presented and then rebuilt in an effort to reach a middle ground between computer resources optimization and output accuracy. Among these algorithms, the biggest emphasis is put on the correlation dimension algorithm by Grassberger and Procaccia which allows for the deduction of the system's embedding dimension. The results derived are then used to build a forecast approach inspired by the analogues method. The purpose of this work is to show there is potential for dynamical systems' modelling tools to be used in financial markets, especially for intra-day purposes where decision and computational times need to be very small.
O teorema de Takens (1981) mostra como uma série de medições obtidas de um dado sistema podem ser usadas para reconstruir o sistema dinâmico original. Neste trabalho, parte-se deste teorema e constrói-se a ponte entre conceitos teóricos e a sua aplicação numérica. Vários algoritmos são apresentados e depois reconstruídos com o objetivo de se atingir um compromisso entre otimização de recursos computacionais e rigor nos resultados. Entre esses algoritmos, a maior ênfase é colocada no do cálculo do integral de correlação de Grassberger-Procaccia que permite a dedução da dimensão de imersão de um dado sistema. Os resultados obtidos são usados na construção de um modelo de previsão inspirado pela abordagem dos pontos análogos, ou método dos análogos. O objetivo deste trabalho é mostrar que existe potencial na aplicação de ferramentas de modelação de sistemas dinâmicos caóticos no mercado financeiro, em especial em transações intra-diárias onde tempos de decisão e computação têm de ser muito reduzidos.