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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Estimating the Trade and Welfare Effects of Brexit: A Panel Data Structural Gravity Model

Oberhofer, Harald, Pfaffermayr, Michael 01 1900 (has links) (PDF)
This paper proposes a new panel data structural gravity approach for estimating the trade and welfare effects of Brexit. The suggested Constrained Poisson Pseudo Maximum Likelihood Estimator exhibits some useful properties for trade policy analysis and allows to obtain estimates and confidence intervals which are consistent with structural trade theory. Assuming different counterfactual post-Brexit scenarios, our main findings suggest that UKs (EUs) exports of goods to the EU (UK) are likely to decline within a range between 7.2% and 45.7% (5.9% and 38.2%) six years after the Brexit has taken place. For the UK, the negative trade effects are only partially offset by an increase in domestic goods trade and trade with third countries, inducing a decline in UKs real income between 1.4% and 5.7% under the hard Brexit scenario. The estimated welfare effects for the EU are negligible in magnitude and statistically not different from zero. / Series: Department of Economics Working Paper Series
92

Teletraffic Models for Mobile Network Connectivity. / Teletrafik Modeller för mobilt nätverk Anslutningar

Venigalla, Thejaswi, Akkapaka, Raj Kiran January 2013 (has links)
We are in an era marked by tremendous global growth in mobile traffic and subscribers due to change in the mobile communication technology from second generation to third and fourth generations. Especially usage of packet-data applications has recorded remarkable growth. The need for mobile communication networks capable of providing an ever increasing spectrum of services calls for efficient techniques for the analysis, monitoring and design of networks. To meet the ever increasing demands of the user and to ensure on reliability and affordability, system models that can capture the characteristics of actual network load and yield acceptable precise predictions of performance in a reasonable amount of time must be developed. This can be achieved using teletraffic models as they capture the behaviour of system through interpret-able functions and parameters. Past years have seen extremely numerous teletraffic models for different purposes. Nevertheless there is no model that provides a proper frame work to analyse the mobile networks. This report attempts to provide a frame work to analyse the mobile traffic and based on the analysis we design teletraffic models that represent the realistic mobile networks and calculate the buffer under-flow probability. / Vi är i en tid präglad av enorm global tillväxt inom mobil trafik och abonnenter på grund av förändringar i den mobila kommunikationsteknikenfrån andra generationen till tredje och fjärde led . Särskilt användningen av paketdataapplikationerhar spelat in en anmärkningsvärd tillväxt . Behovet av mobila kommunikationsnät som kan ge en allt större spektrum av tjänster lyser effektiva metoder för analys , övervakning och utformning av nät . För att möta de ständigt ökande kraven på användaren och för att säkerställa den tillförlitlighet och överkomliga priser , måste systemmodeller som kan fånga egenskaper faktiska belastningen på nätet och ger acceptabla precisa förutsägelser om prestanda i en rimlig tid att utvecklas . Detta kan uppnås med användning av teletrafik modeller som de fångar beteendet hos systemet genom tolka bara funktioner och parametrar . Tidigare år har sett väldigt många teletrafik modeller för olika ändamål . Det är likväl inte modellen som ger en ordentlig ramverk för att analysera de mobilnät. Rapporten försöker ge ett ramverk för att analysera mobiltrafik och baserat på analysen vi designar teletrafik modeller som representerar de realistiska mobilnät och beräkna buffertunderflödesannolikhet .
93

Analysis of an Ill-posed Problem of Estimating the Trend Derivative Using Maximum Likelihood Estimation and the Cramér-Rao Lower Bound

Naeem, Muhammad Farhan January 2020 (has links)
The amount of carbon dioxide in the Earth’s atmosphere has significantly increased in the last few decades as compared to the last 80,000 years approximately. The increase in carbon dioxide levels are affecting the temperature and therefore need to be understood better. In order to study the effects of global events on the carbon dioxide levels, one need to properly estimate the trends in carbon dioxide in the previous years. In this project, we will perform the task of estimating the trend in carbon dioxide measurements taken in Mauna Loa for the last 46 years, also known as the Keeling Curve, using estimation techniques based on a Taylor and Fourier series model equation. To perform the estimation, we will employ Maximum Likelihood Estimation (MLE) and the Cramér-Rao Lower Bound (CRLB) and review our results by comparing it to other estimation techniques. The estimation of the trend in Keeling Curve is well-posed however, the estimation for the first derivative of the trend is an ill-posed problem. We will further calculate if the estimation error is under a suitable limit and conduct statistical analyses for our estimated results.
94

Modely s Weibullovým rozdělením / Model with Weibull responses

Konečná, Tereza January 2017 (has links)
Tato diplomová práce se zabývá Weibullovými modely, přesněji dvouparametrickým Weibullovým rozdělením. Práce se zabývá odhady parametrů, a to čtyřmi variantami kvantilové metody, metodou maximální věrohodnosti a grafickou metodou Weibullova pravděpodobnostního grafu. Je uvedeno odvození odhadu parametrů pro jednovýběrovou analýzu rozptylu pro Weibullovo rozdělení. Jsou zde odvozeny vztahy pro model s konstantním parametrem alfa, s konstantním parametrem beta a s oběma konstantními parametry. Také jsou uvedeny testové statistiky pro rušivé parametry - skórový test, Waldův test a test založený na věrohodnostním poměru. V poslední kapitole je provedena aplikace jednotlivých představených metod. Srovnání metod je ukázáno pomocí grafů, histogramů a tabulek. Metody jsou naprogramovány v~softwaru R. Jejich funkčnost a vlastnosti jsme ověřili na dvou simulovaných souborech dat. Diplomová práce je zakončena příkladem tří simulovaných náhodných výběrů, na kterých byla provedena analýza pomocí zavedených metod.
95

Výběr řádu GARCH modelu / GARCH model selection

Turzová, Kristína January 2021 (has links)
The GARCH model estimates the volatility of a time series. Information criteria are often used to determine orders of the GARCH model, although their suit- ability is not known. This thesis focuses on the order selection of the GARCH model using information criteria. The simulation study investigates whether in- formation criteria are appropriate for the model selection and how the selection depends on the order, number of observations, distribution of innovations, estima- tion method or model parameters. The predictive capabilities of models selected by information criteria are compared to the true model. 1
96

An Estimation Technique for Spin Echo Electron Paramagnetic Resonance

Golub, Frank 29 August 2013 (has links)
No description available.
97

Data Mining with Newton's Method.

Cloyd, James Dale 01 December 2002 (has links) (PDF)
Capable and well-organized data mining algorithms are essential and fundamental to helpful, useful, and successful knowledge discovery in databases. We discuss several data mining algorithms including genetic algorithms (GAs). In addition, we propose a modified multivariate Newton's method (NM) approach to data mining of technical data. Several strategies are employed to stabilize Newton's method to pathological function behavior. NM is compared to GAs and to the simplex evolutionary operation algorithm (EVOP). We find that GAs, NM, and EVOP all perform efficiently for well-behaved global optimization functions with NM providing an exponential improvement in convergence rate. For local optimization problems, we find that GAs and EVOP do not provide the desired convergence rate, accuracy, or precision compared to NM for technical data. We find that GAs are favored for their simplicity while NM would be favored for its performance.
98

Credit scoring using Logistic regression

Hara Khanam, Iftho January 2023 (has links)
In this thesis, we present the use of logistic regression method to develop a credit scoring modelusing the raw data of 4447 customers of a bank. The data of customers is collected under 14independent explanatory variables and 1 default indicator. The objective of this thesis is toidentify optimal coefficients. In order to clean data, the raw data set was put through variousdata calibration techniques such as Kurtosis, Skewness, Winsorization to eliminate outliers.On this winsorized dataset, LOGIT analysis is applied in two rounds with multiple statisticaltests. These tests aim to estimate the significance of each independent variable and modelfitness. The optimal coefficients can be used to obtain the credit scores for new customers witha new data set and rank them according to their credit risk.
99

Assessment of Modern Statistical Modelling Methods for the Association of High-Energy Neutrinos to Astrophysical Sources / Bedömning av moderna statistiska modelleringsmetoder för associering av högenergetiska neutroner till astrofysiska källor

Minoz, Valentin January 2021 (has links)
The search for the sources of astrophysical neutrinos is a central open question in particle astrophysics. Thanks to substantial experimental efforts, we now have large-scale neutrino detectors in the oceans and polar ice. The neutrino sky seems mostly isotropic, but hints of possible source-neutrino associations have started to emerge, leading to much excitement within the astrophysics community. As more data are collected and future experiments planned, the question of how to statistically quantify point source detection in a robust way becomes increasingly pertinent. The standard approach to null-hypothesis testing leads to reporting the results in terms of a p-value, with detection typically corresponding to surpassing the coveted 5-sigma threshold. While widely used, p-values and significance thresholds are notorious in the statistical community as challenging to interpret and potentially misleading. We explore an alternative Bayesian approach to reporting point source detection and the connections and differences with the frequentist view. In this thesis, two methods for associating neutrino events to candidate sources are implemented on data from a simplified simulation of high-energy neutrino generation and detection. One is a maximum likelihood-based method that has been used in some high-profile articles, and the alternative uses Bayesian Hierarchical modelling with Hamiltonian Monte Carlo to sample the joint posterior of key parameters. Both methods are applied to a set of test cases to gauge their differences and similarities when applied on identical data. The comparisons suggest the applicability of this Bayesian approach as alternative or complement to the frequentist, and illustrate how the two approaches differ. A discussion is also conducted on the applicability and validity of the study itself as well as some potential benefits of incorporating a Bayesian framework, with suggestions for additional aspects to analyze. / Sökandet efter källorna till astrofysiska neutriner är en central öppen fråga i astropartikel- fysik. Tack vare omfattande experimentella ansträngningar har vi nu storskaliga neutrino-detektorer i haven och polarisen. Neutrinohimlen verkar mestadels isotropisk, men antydningar till möjliga källneutrinoföreningar har börjat antydas, vilket har lett till mycket spänning inom astrofysikgemenskapen. När mer data samlas in och framtida experiment planeras, blir frågan om hur man statistiskt kvantifierar punktkälledetektering på ett robust sätt alltmer relevant. Standardmetoden för nollhypotes-testning leder ofta till rapportering av resultat i termer av p-värden, då en specifik tröskel i signifikans eftertraktas. Samtidigt som att vara starkt utbredda, är p-värden och signifikansgränser mycket omdiskuterade i det statistiska samfundet angående deras tolkning. Vi utforskar en alternativ Bayesisk inställning till utvärderingen av punktkälldetektering och jämför denna med den frekvensentistiska utgångspunkten. I denna uppsats tillämpas två metoder för att associera neutrinohändelser till kandidatkällor på basis av simulerad data. Den första använder en maximum likelihood-metod anpassad från vissa uppmärksammade rapporter, medan den andra använder Hamiltonsk Monte Carlo till att approximera den gemensamma aposteriorifördelningen hos modellens parametrar. Båda metoderna tillämpas på en uppsättning testfall för att uppskatta deras skillnader och likheter tillämpade på identisk data. Jämförelserna antyder tillämpligheten av den Bayesianska som alternativ eller komplement till den klassiska, och illustrerar hur de två metoderna skiljer sig åt. En diskussion förs också om validiteten av studien i sig samt några potentiella fördelar med att använda ett Bayesiskt ramverk, med förslag på ytterligare aspekter att analysera.
100

Statistical Inference for a New Class of Skew t Distribution and Its Related Properties

Basalamah, Doaa 04 August 2017 (has links)
No description available.

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