Dissertations / Theses on the topic 'Optimal clusters'
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Peng, Shuyue. "Optimal Semantic Labeling of Social Network Clusters." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1406821134.
Full textAdams, Daniel Alan. "Optimal Load Balancing in a Beowulf Cluster." Link to electronic thesis, 2005. http://www.wpi.edu/Pubs/ETD/Available/etd-050205-135758/.
Full textFrigui, Hichem. "New approaches for robust clustering and for estimating the optimal number of clusters /." free to MU campus, to others for purchase, 1997. http://wwwlib.umi.com/cr/mo/fullcit?p9842528.
Full textPanebianco, Gabriele. "A new implementation of an optimal filter for the detection of galaxy clusters through weak lensing." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/24444/.
Full textVanišová, Adéla. "Shluková analýza jako nástroj klasifikace objektů." Master's thesis, Vysoká škola ekonomická v Praze, 2012. http://www.nusl.cz/ntk/nusl-114191.
Full textNovák, Miroslav. "Hodnocení úspěšnosti koeficientů pro stanovení optimálního počtu shluků ve shlukové analýze." Master's thesis, Vysoká škola ekonomická v Praze, 2014. http://www.nusl.cz/ntk/nusl-193328.
Full textOuaalaya, El Hassane. "Phénotypes et trajectoires des patients BPCO, données issues de la cohorte PALOMB." Thesis, Bordeaux, 2020. http://www.theses.fr/2020BORD0295.
Full textCOPD is a heterogeneous and multisystemic disease with progressive increasing morbidity and mortality. The GOLD classification introduces uncertainties, its validity in predicting mortality is still uncertain, and its applicability in practice is more than questionable. Our understanding of the longitudinal determinants of COPD exacerbations remains unclear. COPD patients frequently suffer from comorbidities, with a significant impact on mortality. Evaluating dyspnea in clinical practice is not easy, and it is difficult to assess the respiratory attributable part of dyspnea in patients with comorbidities. Current data remains insufficient to confirm the importance of the majority of candidate phenotypes. Mainly, this work aims to characterize the evolution of the trajectories of COPD patients and to identify candidate phenotypes in COPD patients. Secondly, this work aims to: identify stable clusters of comorbidities, characterize the determinants of dyspnoea, determine the factors associated with the phenotypes of frequent exacerbators and assess the impact of symptoms, pulmonary functions and comorbidities on mortality. Diagnosis of COPD was made using spirometry with post-BD FEV1/FVC <70%. Since January 2014, pulmonologists have been using the PALOMB web site questionnaire to include COPD patients. This questionnaire included the following domains: demographic criteria, clinical symptoms, lung function, comorbidities and therapeutic management. After 5 years of follow-up, vital status was recorded through the RNIPP. Stable clusters of comorbidities were identified using the supervised classification models on the principal components. The sensitivity analysis and the least absolute shrinkage and selection operator (LASSO) were then used to assess the determinants of dyspnea. The unsupervised classification was used to identify three phenotypes by modelling the longitudinal changes in the frequency of COPD exacerbations. In addition, the Cox model was used to identify factors associated with all-cause mortality. Classification and regression trees (CART) were used for allocating patients to the subgroups and clinical relevance was determined by comparing 5-year mortality. The most optimal cluster analysis (supervised vs unsupervised) was used to robustly identify clinical phenotypes. The cluster analysis showed five phenotypes of comorbidities: cluster 1 included cardiac profile; cluster 2 included less comorbidities; cluster 3 included metabolic syndrome, apnea and anxiety-depression; cluster 4 included malnutrition and osteoporosis and cluster 5 included bronchiectasis. Regardless of the cut-off values set to identify higher dyspnoea, our results suggested that dyspnoea is related to the severity of airflow limitation, gender, exacerbations, comorbidities and hyperinflation. Revealing that the hyperinflation defined by IC/TLC ratio was a better determinant of the mMRC dyspnoea scale in comparison to both RV/TLC and FRC/TLC ratio. Based on our hypothesis, we were able to determine four phenotypes: A (infrequent), B (frequent in underweight patients), C (transient), and D (frequent in obese patients). The most important determinants of the frequent exacerbating phenotype are: the presence of anxiety, chronic sputum, and unvaccinated against influenza. In addition to known criteria related to COPD severity, cancer and cardiovascular comorbidities contribute to increased mortality in COPD patients. Our results show that within the Palomb cohort (a large clinic-based cohort) multimorbidity is frequent, heterogeneous and varies according to the stage of COPD severity. The presence of comorbidities should therefore be included in any assessment of COPD severity. These cohort results illustrate in real-life the multifactorial aspect of dyspnoea in COPD patients, confirm the existence and clinical relevance of two frequent exacerbators’ phenotypes and the currently used threshold to define this phenotype
Lima, Ana Isabel Lage Figueiredo. "Alargamento da UEM : choques assimétricos e identificação de clusters." Master's thesis, Instituto Superior de Economia e Gestão, 2004. http://hdl.handle.net/10400.5/4165.
Full textCom a aproximação da data de adesão formal dos dez Países em Adesão à União Europeia, muitos autores têm-se debruçado sobre a questão da adesão prospectiva destes países à Zona Euro. À luz da teoria das Zonas Monetárias Óptimas, a perda da autonomia na condução da política monetária e cambial constitui o principal custo económico associado à adopção do euro por parte destes países, ao limitar os instrumentos disponíveis aos Estados-membros para acomodar eventuais choques assimétricos. Neste trabalho, considerei um modelo vector autoregressivo (VAR) estrutural para identificar e comparar os choques de procura e de oferta entre os Estados-membros da Zona Euro e os Países em Adesão. De forma a avaliar o grau de simetria entre os choques da Zona Euro e dos Países em Adesão, considerei duas abordagens distintas: o cálculo das correlações dos choques de procura e oferta entre os vários países e a UEM e a análise de clusters. Recorrendo ainda à análise de clusters, procurei também identificar grupo homogéneos de países dentro da futura UE e analisar a sua evolução ao longo do tempo. Os resultados obtidos neste estudo relativamente ao período 1996-2002 revelam que os Países em Adesão estão, em geral, menos correlacionados com os choques de oferta e de procura da Zona Euro que os actuais Estados-membros da UEM. No entanto, o cenário em termos individuais é bastante heterogéneo. Em particular, alguns Países em Adesão mais avançados, a Hungria e a Polónia, já se encontram ao nível dos países de menor dimensão da UEM (nomeadamente Portugal e a Grécia). Em contrapartida, em países como Lituânia e a Eslováquia, a correlação entre os choques permanece baixa, o que implica que um avanço rápido para a adopção do euro traria eventualmente elevados custos de estabilização para estes países.
On the eve of the formal accession of the ten Accession Countries into the European Union, many authors have been discussing the implications of the upcoming integration of these countries in the Euro Area. Under the Optimum Currency Areas (OCA) theory, the loss of monetary autonomy and exchange rate flexibility constitutes the main economic cost associated with the adoption of the euro, thus limiting the instruments for adjusting asymmetric shocks available to member countries. In this paper, I used a structural vector autoregression model to identify and compare demand and supply shocks between euro area countries and the accession countries. In order to assess the degree of symmetry between euro area and accession countries shocks, 1 considered two ditterent approaches: the correlation between shocks and cluster analysis. With the help of cluster analysis, I also tried to identify homogenous groups of countries within the future EU, and analyse their evolution through time. Focusing on the period 1996-2002, the results show that the accession countries are generally less correlated with euro area supply and demand shocks than the EMU Member Countries. However, when considering individual countries, a different picture emerges. The more advanced Accession Countries (namely Hungary and Poland) are hardly different in the correlation of their shocks vis-a-vis the euro area than the smaller countries of the EMU (i.e. Portugal and Greece). At the same time, countries like Lithuania and Slovakia show a low correlation with euro area shocks, implying that moving fast towards the adoption of the euro may eventually generate high stabilization costs for these countries.
Girish, Deeptha S. "Thresholded K-means Algorithm for Image Segmentation." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1479815784173769.
Full textHammerbauer, Jiří. "Hodnocení úspěšnosti metod a koeficientů využívaných ve shlukové analýze." Master's thesis, Vysoká škola ekonomická v Praze, 2014. http://www.nusl.cz/ntk/nusl-193440.
Full textDietrich, Florian. "Analyse et contrôle de systèmes de dynamiques d'opinions." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0214/document.
Full textOpinion dynamics systems aroused renewed interest in the Control System Theory and Applied Mathematics communities. This can be explained by the emergence of online social networks and the possibility of exploiting and understanding associated behaviours and data. Opinion dynamic models are special cases of multi-agent systems. These systems have various applications such as controlling the behaviour of a fleet of collaborative robots. A system of opinion dynamics is thus composed of several agents. The state of each agent is then modeled by a real number, which represents the agent's opinion on a certain subject. The mathematical models of opinion dynamics then describe the evolution of agents' opinions over time. Many results have been obtained on the asymptotic behaviour of these systems, notably on convergence towards consensus, when the opinion of all agents of the system tend towards the same value. The less well known transient state also presents interesting phenomena such as the formation of local transient agreements, which are more tricky to define. A study of these phenomena is presented for discrete-time opinion dynamics systems with generic state dependent influence functions. The main contribution proposes a criterion for detecting the formation of these local agreements, as well as a prediction of the duration during which this criterion is verified. The second part of this thesis focuses on opinion dynamics in continuous time in which one of the agents, called leader, has a particular role: the evolution of its opinion is controllable. For systems with time and state-dependent influence functions and under certain conditions, a control law is presented that allows the leader to gather all agents in its neighbourhood in finite time and then steer them to a desired consensus value. In addition, the problem of time optimal control which consists in bringing all agents together in the neighborhood of the leader in minimal time is also examined for the case of only state-dependent influence functions. The Pontryagin Maximum Principle specifies the class of admissible optimal controls with implicit expressions within a general framework. For the particular case where there is no interaction between agents, the time-optimal control law has been obtained in practice for any initial conditions
Černý, Andrej. "Shluky zemí EU s využitím socio-ekonomických ukazatelů." Master's thesis, Vysoká škola ekonomická v Praze, 2013. http://www.nusl.cz/ntk/nusl-197464.
Full textLöster, Tomáš. "Hodnocení výsledků metod shlukové analýzy." Doctoral thesis, Vysoká škola ekonomická v Praze, 2004. http://www.nusl.cz/ntk/nusl-77096.
Full textFarrens, S. "Optical detection of galaxy clusters." Thesis, University College London (University of London), 2011. http://discovery.ucl.ac.uk/1318077/.
Full textGelsin, Alexander [Verfasser], and Matthias [Akademischer Betreuer] Bartelmann. "Galaxy Cluster Detection using Optimal Matched Filtering in Optical Bands / Alexander Gelsin ; Betreuer: Matthias Bartelmann." Heidelberg : Universitätsbibliothek Heidelberg, 2015. http://d-nb.info/1180499514/34.
Full textRivera, Echeverri José David [UNESP]. "Cosmological analysis of optical galaxy clusters." Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/152493.
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Os aglomerados de galáxias são os maiores objetos ligados que observamos no universo. Dado que as galáxias são consideradas traçadores de matéria escura, os aglomerados de galáxias nos permitem estudar a formação e a evolução de estruturas em grande escala. As contagens do número de aglomerados de galáxias são sensı́veis ao modelo cosmológico, portanto são usadas como observáveis para restringir os parâmetros cosmológicos. Nesta tese estudamos os aglomerados de galáxias óticos. Iniciamos o trabalho analisando a degradação da precisão e a exatidão no desvio para o vermelho fotométrico estimado através de métodos de aprendizagem de máquina (machine learning) ANNz2 e GPz. Além do valor singular do desvio para o vermelho fotométrico clássico (isto é, valor médio ou máximo da distribuição), implementamos um estimador baseado em uma amostragem de Monte Carlo usando a função de distribuição cumulativa. Mostramos que este estimador para o algoritmo ANNz2 apresenta a melhor concorância com a distribuição do desvio para o vermelho espectroscópico, no entanto, uma maior dispersão. Por outro lado, apresentamos o buscador de aglomerados VT-FOFz, o qual combina as técnicas de Voronoi Tessellation e Friends of Friends. Estimamos seu desempenho através de catálogos simulados. Calculamos a completeza e a pureza usando uma região de cilindrica no espaço 2+1 (ou seja, coordenadas angulares e desvio para o vermelho). Para halos maciços e aglomerados com alta riqueza, obtemos valores elevados de completeza e pureza. Comparamos os grupos de galáxias detectados através do buscador de aglomera- dos VT-FOFz com o catálogo RedMaPPer SDSS DR8. Recuperamos ∼ 90% dos aglomerados de galáxias do catálogo RedMaPPer até o desvio para o vermelho de z ≈ 0.33 considerando galáxias mais brilhantes com r < 20.6. Finalmente, realizamos uma previsão cosmológica usando um método MCMC para um modelo plano de wCDM por meio da abundância de aglomerados de galáxias. O modelo fiducial é um universo ΛCDM plano. Os efeitos devidos à massa observável estimada e aos deslocamentos para o vermelho fotométricos são incluı́dos através de um modelo de auto-calibração. Empregamos a função de massa de Tinker para estimar o número de contagens em uma faixa de massa e um bin de deslocamento para o vermelho. Assumimos que a riqueza e a massa do aglomerado estejam relacionadas através de uma lei de potência. Recuperamos os valores fiduciais com nı́vel de confiança de até 2σ para os testes considerados.
The galaxy clusters are the largest bound objects observed in the universe. Given that the galaxies are considered as tracers of dark matter, the galaxy clusters allow us to study the formation and evolution of large-scale structures. The cluster number counts are sensitive to the cosmological model, hence they are used as probes to constrain the cosmological parameters. In this work we focus on the study of optical galaxy clusters. We start analyzing the degradation of both precision and accuracy in the estimated photometric redshift via ANNz2 and GPz machine learning methods. In addition to the classical singular value for the photometric redshift (i.e., mean value or maximum of the distribution), we implement an estimator based on a Monte Carlo sampling by using the cumulative distribution function. We show that this estimator for the ANNz2 algorithm presents the best agreement with the distribution for spectroscopic redshift, nonetheless a higher scattering. On the other hand, we present the VT-FOFz cluster finder, which combines the techniques Voronoi Tessellation and Friends of Friends. Through mock catalogs, we estimate its performance. We compute the completeness and purity by using a cylindrical region in the 2+1 space (i.e., angular coordinates and redshift). For massive haloes and clusters with high richness, we obtain high values of completeness and purity. We compare the detected galaxy clusters via the VT-FOFz cluster finder with the redMaPPer SDSS DR8 cluster catalog. We recover ∼ 90% of the galaxy clusters of the redMaPPer catalog until the redshift z ≈ 0.33 considering brighter galaxies with r < 20.6. Finally, we perform a cosmological forecasting by using a MCMC method, for a flat wCDM model through galaxy cluster abundance. The fiducial model is a flat ΛCDM Universe. The effects due to the estimated observable mass and the photometric redshifts are included via a self-calibriation model. We employ the Tinker’s mass function to estimate the number counts in a range of mass and a redshift bin. We assume that the richness and the cluster mass are related through a power law. We recover the fiducial values at 2σ confindence level for the considered tests.
Rivera, Echeverri José David. "Cosmological analysis of optical galaxy clusters /." São Paulo, 2017. http://hdl.handle.net/11449/152493.
Full textCoorientador: Filipe Batoni Abdalla
Banca: Filipe Batoni Abdalla
Banca: Laerte Sodré Júnior
Banca: Marcos Vinícius Borges Teixeira Lima
Banca: Martín Makler
Resumo: Os aglomerados de galáxias são os maiores objetos ligados que observamos no universo. Dado que as galáxias são consideradas traçadores de matéria escura, os aglomerados de galáxias nos permitem estudar a formação e a evolução de estruturas em grande escala. As contagens do número de aglomerados de galáxias são sensı́veis ao modelo cosmológico, portanto são usadas como observáveis para restringir os parâmetros cosmológicos. Nesta tese estudamos os aglomerados de galáxias óticos. Iniciamos o trabalho analisando a degradação da precisão e a exatidão no desvio para o vermelho fotométrico estimado através de métodos de aprendizagem de máquina (machine learning) ANNz2 e GPz. Além do valor singular do desvio para o vermelho fotométrico clássico (isto é, valor médio ou máximo da distribuição), implementamos um estimador baseado em uma amostragem de Monte Carlo usando a função de distribuição cumulativa. Mostramos que este estimador para o algoritmo ANNz2 apresenta a melhor concorância com a distribuição do desvio para o vermelho espectroscópico, no entanto, uma maior dispersão. Por outro lado, apresentamos o buscador de aglomerados VT-FOFz, o qual combina as técnicas de Voronoi Tessellation e Friends of Friends. Estimamos seu desempenho através de catálogos simulados. Calculamos a completeza e a pureza usando uma região de cilindrica no espaço 2+1 (ou seja, coordenadas angulares e desvio para o vermelho). Para halos maciços e aglomerados com alta riqueza, obtemos valores elevados de ... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The galaxy clusters are the largest bound objects observed in the universe. Given that the galaxies are considered as tracers of dark matter, the galaxy clusters allow us to study the formation and evolution of large-scale structures. The cluster number counts are sensitive to the cosmological model, hence they are used as probes to constrain the cosmological parameters. In this work we focus on the study of optical galaxy clusters. We start analyzing the degradation of both precision and accuracy in the estimated photometric redshift via ANNz2 and GPz machine learning methods. In addition to the classical singular value for the photometric redshift (i.e., mean value or maximum of the distribution), we implement an estimator based on a Monte Carlo sampling by using the cumulative distribution function. We show that this estimator for the ANNz2 algorithm presents the best agreement with the distribution for spectroscopic redshift, nonetheless a higher scattering. On the other hand, we present the VT-FOFz cluster finder, which combines the techniques Voronoi Tessellation and Friends of Friends. Through mock catalogs, we estimate its performance. We compute the completeness and purity by using a cylindrical region in the 2+1 space (i.e., angular coordinates and redshift). For massive haloes and clusters with high richness, we obtain high values of completeness and purity. We compare the detected galaxy clusters via the VT-FOFz cluster finder with the redMaPPer SDSS DR8 cluster catalog. We recover ∼ 90% of the galaxy clusters of the redMaPPer catalog until the redshift z ≈ 0.33 considering brighter galaxies with r < 20.6. Finally, we perform a cosmological forecasting by using a MCMC method, for a flat wCDM model through galaxy cluster abundance. The fiducial model is a flat ΛCDM Universe. The effects due to the estimated observable mass and (Complete abstract click electronic access below)
Doutor
Rastelli, Riccardo, and Nial Friel. "Optimal Bayesian estimators for latent variable cluster models." Springer Nature, 2018. http://dx.doi.org/10.1007/s11222-017-9786-y.
Full textRosvick, Joanne Marie. "Optical and near-infrared photometry of old galactic clusters." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1996. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq21945.pdf.
Full textHood, Ross John. "Characterising the optical properties of galaxy clusters with GMPhoRCC." Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/9638.
Full textGrover, Cam J. "Nature of Bonding in Bimetallic or Ligated Aluminum Clusters." VCU Scholars Compass, 2017. http://scholarscompass.vcu.edu/etd/4828.
Full textWindridge, David. "A fluctuation analysis for optical cluster galaxies." Thesis, University of Bristol, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302173.
Full textHuang, Hsiu-Hui. "X-ray and Optical observations of Globular Clusters and Pulsars." Diss., lmu, 2010. http://nbn-resolving.de/urn:nbn:de:bvb:19-123830.
Full textRuel, Jonathan. "Optical Spectroscopy and Velocity Dispersions of SZ-Selected Galaxy Clusters." Thesis, Harvard University, 2013. http://dissertations.umi.com/gsas.harvard:10865.
Full textPhysics
Kennedy, David Colm John. "Optical and radio observations of interstellar gas towards globular clusters." Thesis, Queen's University Belfast, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263400.
Full textHilton, Matthew James. "The optical properties of galaxies in X-ray selected clusters." Thesis, Liverpool John Moores University, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.439051.
Full textAlshino, Abdulmonem. "Evolution of X-ray and optical properties of galaxy clusters." Thesis, University of Birmingham, 2010. http://etheses.bham.ac.uk//id/eprint/1267/.
Full textSinha, Roy Rajarshi. "Ab initio simulation of optical properties of noble-metal clusters." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0017/document.
Full textThe fundamental research interest in nanometric pieces of noble metals is mainly due to the localized surface-plasmon resonance (LSPR) in the optical absorption. Different aspects related to the theoretical understanding of LSPRs in `intermediate-size' noble-metal clusters are studied in this thesis. To gain a broader perspective both the real-time \ai formalism of \td density-functional theory (RT-TDDFT) and the classical electromagnetics approach are employed. A systematic and detailed comparison of these two approaches highlights and quantifies the limitations of the electromagnetics approach when applied to quantum-sized systems. The differences between collective plasmonic excitations and the excitations involving $d$-electrons, as well as the interplay between them are explored in the spatial behaviour of the corresponding induced densities by performing the spatially resolved Fourier transform of the time-dependent induced density obtained from a RT-TDDFT simulation using a $\delta$-kick perturbation. In this thesis, both bare and ligand-protected noble-metal clusters were studied. In particular, motivated by recent experiments on plasmon emergence phenomena, the TDDFT study of Au-Cu nanoalloys in the size range just below 2~nm produced subtle insights into the general effects of alloying on the optical response of these systems
Braglia, Filiberto Giorgio. "Study of optical properties and galaxy populations of galaxy clusters." Diss., kostenfrei, 2008. http://edoc.ub.uni-muenchen.de/9179/.
Full textWatkins, Mark James. "High resolution spectroscopy and ab initio studies of weakly bound clusters." Thesis, University of York, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325780.
Full textCRABTREE, JASON PAUL. "OPTIMAL PREVENTIVE MAINTENANCE SCHEDULING IN SEMICONDUCTOR FABS." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1060889327.
Full textPietka-Eddleston, Magdalena. "Optical And Near Infrared Studies of Cluster Galaxies." Thesis, University of Nottingham, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.523662.
Full textJoo, Jaewoo. "Atomic and Optical Realizations of Cluster Quantum Computation." Thesis, Imperial College London, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.484425.
Full textLicitra, Rossella. "Galaxy cluster detection with optical and infrared imaging." Paris 7, 2014. http://www.theses.fr/2014PA077149.
Full textBeing galaxy clusters the most massive bound structures in the Universe, they represent a powerful tool to probe the large-scale structure predicted by the standard cosmological model, and to understand how environmental effects affect galaxy evolution. To conduct these studies and obtain reliable results, it is important to build complete and pure cluster catalogs. The use of these catalogs for cosmology requires accurate estimates of cluster mass. In this work, I describe the cluster detection algorithm that I developed during my PhD thesis : Red-GOLD, and the results that I obtained by applying i to current multi-wavelength surveys. My algorithm is based on the detection of galaxy overdensities and the characterisation of their red-sequence. The algorithm finds red galaxy overdensities with respect to the mean background. I select red galaxies using color predictions given by stellar population synthesis models and impose color limits as a function of redshift. Among those galaxies, I discern the early-type galaxies from their spectral type. I then identify cluster members using accurate photometric redshifts, and estimate the cluster candidate richness. I applied Red-GOLD to optical data coming from two different surveys, the Next Generatiôn Virgo Cluster Survey (NGVS) and the Canada-France-Hawaii Telescope Lensing Survey (CFHTLS) and detected galaxy cluster candidates up to redshift z=1. I assessed the performances of my algorithm by applying it to simulated galaxy catalogs from the Millennium simulations. My cluster catalogue is complete at the 80% up to redshift z=1 and pure at 81%
Mitric, Roland. "Structure-reactivity relation, optical properties and real-time study of ultrafast processes in atomic clusters." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2003. http://dx.doi.org/10.18452/15007.
Full textThe study of the nonscalable properties of clusters in the size regime in which each atom counts have shown that fully new phenomena and striking new unexpected properties of small clusters can emerge. In this work three aspects have been addressed: i) the structural and electronic properties and reactivity of metal clusters, ii) stationary optical propertis and iii) real time investigation and control of ultrafast processes in noble metal and in nonstoichiometric sodium fluoride clusters.
Toni, Greta. "Detection and characterization of galaxy clusters in the COSMOS field with the AMICO algorithm." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2022. http://amslaurea.unibo.it/25229/.
Full textChan, Chi-chung Jeffrey, and 陳祉聰. "Kinematic constraints on structuring of the optical emission-line nebula in NGC 1275." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B49799666.
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Physics
Master
Master of Philosophy
Katayama, Masaaki, Takaya Yamazato, and Zheng Huang. "Optimal Cluster Partitioning for Wireless Sensor Networks with Cooperative MISO Scheme." IEEE, 2010. http://hdl.handle.net/2237/14500.
Full textGuo, Rui Murray Royce W. "Monolayer protected clusters synthesis, electrochemistry, ligand exchange kientics [sic] and optical properties /." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2006. http://dc.lib.unc.edu/u?/etd,374.
Full textTitle from electronic title page (viewed Oct. 10, 2007). "... in partial fulfillment of the requireme nts for the degree of Doctor of Philosophy in the Department of Chemistry (Analytical Chemistry)." Discipline: Chemistry; Department/School: Chemistry.
Fairley, Bruce William. "X-ray and optical studeis of the evolution of clusters of galaxies." Thesis, Oxford Brookes University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289250.
Full textHolland, John Gerrard. "Optical and X-ray structures in the REXCESS sample of galaxy clusters." Diss., Ludwig-Maximilians-Universität München, 2015. http://nbn-resolving.de/urn:nbn:de:bvb:19-183490.
Full textGalaxy clusters are the largest and most massive gravitationally bound objects in the Universe which have had time to collapse and virialise. The intra cluster medium (ICM) within clusters is a plasma seen in the X-ray band. Galaxies within clusters are visible in the optical band and are primarily red and have low star formation rates. Newly accreted galaxies may have more star formation and bluer colours, but they become red as galaxies interact with the ICM. Growth of clusters occurs by sporadic mergers with other galaxy groups/clusters, or through smooth accretion of galaxies from clusters' surroundings. In order to answer the key question `Are X-ray and optical measurements of galaxy clusters complementary, or do they show the same things?' we carried out a study comparing the distribution of galaxies and ICM in galaxy clusters. In particular, we investigated whether optical data gave additional information about the dynamical state of individual clusters which could not be recovered from X-ray data alone. Imaging surveys in optical and X-ray which are expected in the coming decades will provide similar data for much larger regions of the Universe which can be analysed using the techniques we investigated. We used wide field optical images from the MPG/ESO 2.2 m telescope and X-ray data from XMM-Newton to investigate the distribution of galaxies within clusters as compared with the ICM. The 1D radial distribution of the red galaxies was found to match the ICM, but the blue galaxies had a much flatter distribution. Using 2D maps of the clusters, we found that the distribution of red galaxies was similar to that of the ICM, but most clusters also contained red galaxy sub-clumps which were unvirialised. The blue galaxies had insufficient time to virialise as they were stripped of their star forming gas by ram pressure stripping by the ICM within their first crossing of the cluster and became red. X-ray observations are better for determining the recent merger history of galaxy clusters because they retain the signatures of mergers for a shorter period of time. We identified several red clumps of galaxies which appeared to be on infall trajectories into the clusters, and which still retained significant amounts of X-ray emitting gas.
Bürgel, Christian. "Functionality of noble-metal clusters." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2009. http://dx.doi.org/10.18452/15887.
Full textIn this thesis, the unique novel properties of noble metal clusters which arise in the sub-nanometer size regime due to quantum confinement have been theoretically explored. It has been demonstrated that by adding or removing a single atom the chemical and physical properties and functionality of noble-metal clusters can strongly change. The theoretical results have been derived in close cooperation with experimental findings of partner groups demonstrating that by joint theoretical and experimental efforts thorough understanding of fundamental processes and underlying mechanisms can be achieved. This thesis addresses the reactivity of charged gas-phase gold-oxide clusters in the context of the heterogeneous gold nano-catalysis, the ultrafast dynamical properties of noble-metal clusters and their complexes, and the optical properties of silver clusters at surfaces.
Bermeo-Hernandez, Alberto. "The XMM cluster survey : optical to X-ray scaling relations." Thesis, University of Sussex, 2017. http://sro.sussex.ac.uk/id/eprint/72035/.
Full textRafferty, David A. "Feedback in Cluster Cores." Ohio University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1186765820.
Full textRafipoor, Mona [Verfasser], and Holger [Akademischer Betreuer] Lange. "Structural and optical properties of semiconductor nanoparticle clusters / Mona Rafipoor ; Betreuer: Holger Lange." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2018. http://d-nb.info/1170322360/34.
Full textDeutsch, Eric W. "The optical counterparts of the luminous x-ray binary stars in globular clusters /." Thesis, Connect to this title online; UW restricted, 1998. http://hdl.handle.net/1773/5414.
Full textTam, Mary Christina. "Ab initio Calculations of Optical Rotation." Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/27214.
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Zhao, Jianmin. "Optimal Clustering: Genetic Constrained K-Means and Linear Programming Algorithms." VCU Scholars Compass, 2006. http://hdl.handle.net/10156/1583.
Full textSohrmann, Christoph, and Jens Eller. "Optimal Layer Design." Bachelor's thesis, Universitätsbibliothek Chemnitz, 2004. http://nbn-resolving.de/urn:nbn:de:swb:ch1-200401468.
Full textDiese Bachelorarbeit befasst sich mit numerischen Untersuchungen zum optimalen Design von schützenden Mehrschichtbeschichtungen, die einer externen, Hertzschen Last ausgesetzt sind. Hinsichtlich der mechanischen Zuverlässigkeit und Haltbarkeit von Substrat und Beschichtung, versuchen wir die beste Zusammensetzung von gegebenen Materialien mit möglichst geringem Rechenaufwand zu finden. Die numerischen Berechungen wurden mit der Simulationssoftware ELASTICA durchgeführt, welches das erste kommerzielle, nicht-FEM-basierte Programm zur Berechnung von Stressfeldern innerhalb mehrfach beschichteter, elastischer Materialien darstellt. Dafür benutzten wir auf dem massiven Parrallelrechner CLiC (Chemnitzer Linux Cluster) unsere Windows basierte Anwendung unter der Emulationssoftware Wine. Das Ergebnis der Optimierung hängt im allgemeinen sehr stark von der Qualität der Eingangsparameter (z.B. Materialeigenschaften) ab, welche nicht immer in der erwünschten Genauigkeit vorliegen. Es wird gezeigt, dass die in dieser Arbeit vorgestellte Vorgehensweise sehr gute Resultate liefert und für reale Anwendungen einen äusserst ressourcenschonenden Lösungsweg darstellt
Saro, A., S. Bocquet, J. Mohr, E. Rozo, B. A. Benson, S. Dodelson, E. S. Rykoff, et al. "Optical-SZE scaling relations for DES optically selected clusters within the SPT-SZ Survey." OXFORD UNIV PRESS, 2017. http://hdl.handle.net/10150/624426.
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