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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.
21

Model-Free Variable Selection For Two Groups of Variables

Alothman, Ahmad January 2018 (has links)
In this dissertation we introduce two variable selection procedures for multivariate responses. Our procedures are based on sufficient dimension reduction concepts and are model-free. In the first procedure we consider the dual marginal coordinate hypotheses, where the role of the predictor and the response is not important. Motivated by canonical correlation analysis (CCA), we propose a CCA-based test for the dual marginal coordinate hypotheses, and devise a joint backward selection algorithm for dual model-free variable selection. The second procedure is based on ordinary least squares (OLS). We derive and study the asymptotic properties of the OLS-based test under the normality assumption of the predictors as well as an asymmetry assumption. When these assumptions are violated, the asymptotic test with elliptical trimming and clustering is still valid with desirable numerical performances. A backward selection algorithm for the predictor is also provided for the OLS-based test. The performances of the proposed tests and the variable selection procedures are evaluated through synthetic examples and a real data analysis. / Statistics
22

From the Outside In: A Multivariate Correlational Analysis of Effectiveness in Communities of Practice

Bomar, Shannon Hulbert 08 1900 (has links)
Online communities of practice (CoPs) provide social spaces for people to connect, learn, and engage with one another around shared interests and passions. CoPs are innovatively employed within industry and education for their inherent knowledge management characteristics and as a means of improving professional practice. Measuring the success of a CoP is a challenge researchers are examining through various strategies. Recent literature supports measuring community effectiveness through the perceptions of its members; however, evaluating a community by means of member perception introduces complicating factors from outside the community. In order to gain insight into the importance of external factors, this quantitative study examined the influence of factors in the professional lives of educators on their perceptions of their CoP experience. Through an empirical examination of CoPs employed to connect educators and advance their professional learning, canonical correlation analysis was used to examine correlations between factors believed to be influential on the experiences of community members.
23

Generalização da técnica de correlação canônica para aplicações em interface cérebro-máquina /

Brogin, João Angelo Ferres. January 2018 (has links)
Orientador: Douglas Domingues Bueno / Resumo: A busca por uma melhor compreensão das regiões do cérebro e suas funções nas ações humanas tem sido uma tarefa árdua, porém muito útil, principalmente para aplicações da engenharia de interface cérebro-máquina (ICM), bem como para o auxílio a diagnósticos médicos a partir de sinais obtidos dos pacientes em avaliação. No contexto do presente trabalho, destacam-se os trabalhos de interface cérebro-máquina (ICM) pela abrangência no envolvimento de técnicas, métodos e ferramentas comumente estudadas nos cursos de engenharia. Em particular, análises envolvendo técnicas de processamento de sinais de eletroencefalograma (EEG) têm se mostrado de significativa importância para o desenvolvimento dessa área. Uma abordagem amplamente utilizada nesse contexto é a ICM usando Potenciais Visuais Evocados de Estados Estacionários (SSVEP, do inglês Steady-State Visual Evoked Potentials), que, de forma geral, são sinais caracterizados pela resposta evocada do cérebro a estímulos visuais modulados em uma frequência específica. Assim, este trabalho tem o objetivo de propor uma generalização do coeficiente de correlação, conceito-base da análise de correlação canônica (CCA), técnica que tem se mostrado robusta e eficiente no reconhecimento de padrões, especialmente no caso dos SSVEP, e detalhar seu comportamento em função dos parâmetros relevantes para se estabelecer melhores práticas de uso em aplicações de ICM, incluindo fatores fisiológicos, técnicos e operacionais. / Abstract: The search for a better understanding of the brain's anatomy and its functions on human actions has been a harsh yet very useful task, especially for brain-computer interface engineering applications, as well as for medical diagnosis using signals from patients. In the context of this work, brain-computer interface (BCI) applications are highlighted due to their compreehensiveness related to techniques, methods and tools commonly studied in engineering. In particular, analyses involving eletroencephalogram (EEG) signals processing have proven to be of great significance for developing this field of study. A widely used approach is Steady State Visual Evoked Potentials (SSVEP) based BCI, which, in general, are signals characterized by the brain’s evoked response to visual stimuli modulated at a certain frequency. This work aims thus to propose a generalization of the correlation coefficient, which entails Canonical Correlation Analysis (CCA), a technique that has presented robustness and efficiency for pattern recognition, especially in SSVEP-based BCIs, and describe its behavior under relevant varying parameters to stablish better use practices in BCI applications, comprising physiological, technical and operational factors. / Mestre
24

Applications of Knowledge Discovery in Quality Registries - Predicting Recurrence of Breast Cancer and Analyzing Non-compliance with a Clinical Guideline

Razavi, Amir Reza January 2007 (has links)
In medicine, data are produced from different sources and continuously stored in data depositories. Examples of these growing databases are quality registries. In Sweden, there are many cancer registries where data on cancer patients are gathered and recorded and are used mainly for reporting survival analyses to high level health authorities. In this thesis, a breast cancer quality registry operating in South-East of Sweden is used as the data source for newer analytical techniques, i.e. data mining as a part of knowledge discovery in databases (KDD) methodology. Analyses are done to sift through these data in order to find interesting information and hidden knowledge. KDD consists of multiple steps, starting with gathering data from different sources and preparing them in data pre-processing stages prior to data mining. Data were cleaned from outliers and noise and missing values were handled. Then a proper subset of the data was chosen by canonical correlation analysis (CCA) in a dimensionality reduction step. This technique was chosen because there were multiple outcomes, and variables had complex relationship to one another. After data were prepared, they were analyzed with a data mining method. Decision tree induction as a simple and efficient method was used to mine the data. To show the benefits of proper data pre-processing, results from data mining with pre-processing of the data were compared with results from data mining without data pre-processing. The comparison showed that data pre-processing results in a more compact model with a better performance in predicting the recurrence of cancer. An important part of knowledge discovery in medicine is to increase the involvement of medical experts in the process. This starts with enquiry about current problems in their field, which leads to finding areas where computer support can be helpful. The experts can suggest potentially important variables and should then approve and validate new patterns or knowledge as predictive or descriptive models. If it can be shown that the performance of a model is comparable to domain experts, it is more probable that the model will be used to support physicians in their daily decision-making. In this thesis, we validated the model by comparing predictions done by data mining and those made by domain experts without finding any significant difference between them. Breast cancer patients who are treated with mastectomy are recommended to receive radiotherapy. This treatment is called postmastectomy radiotherapy (PMRT) and there is a guideline for prescribing it. A history of this treatment is stored in breast cancer registries. We analyzed these datasets using rules from a clinical guideline and identified cases that had not been treated according to the PMRT guideline. Data mining revealed some patterns of non-compliance with the PMRT guideline. Further analysis with data mining revealed some reasons for guideline non-compliance. These patterns were then compared with reasons acquired from manual inspection of patient records. The comparisons showed that patterns resulting from data mining were limited to the stored variables in the registry. A prerequisite for better results is availability of comprehensive datasets. Medicine can take advantage of KDD methodology in different ways. The main advantage is being able to reuse information and explore hidden knowledge that can be obtained using advanced analysis techniques. The results depend on good collaboration between medical informaticians and domain experts and the availability of high quality data.
25

Gestão ambiental e aspectos estruturais em empresas industriais catarinenses / Environmental management and structural aspects in catarinense industrial companies

Pereira, Filipe Ivo 30 March 2015 (has links)
Made available in DSpace on 2016-12-01T19:11:35Z (GMT). No. of bitstreams: 1 122188.pdf: 2543611 bytes, checksum: 8addab87fdb66b12a28c89fd49c3ae41 (MD5) Previous issue date: 2015-03-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O objetivo desta pesquisa foi analisar a relação existente entre a estrutura organizacional e as práticas de gestão ambiental das empresas industriais catarinenses. O objeto de estudo foram as empresas industriais catarinenses cadastradas na base de dados da Federação das Indústrias do Estado de Santa Catarina. A pergunta de pesquisa que norteou o trabalho foi: existe relação entre a estrutura organizacional e a prática de gestão ambiental das empresas industriais catarinenses? Para tanto, buscou-se na fundamentação teórica abordar os principais conceitos sobre gestão ambiental e estrutura organizacional, sendo abordado na primeira parte os temas relativos às indústrias, o meio ambiente e a gestão ambiental e, na segunda parte os temas relativos à estrutura organizacional e sua relação com a gestão ambiental. Este trabalho enquadra-se como uma pesquisa quantitativa de caráter descritivo. Foi empregado como procedimento de investigação a análise documental. Como métodos estatísticos foram utilizados exploratoriamente a análise descritiva, o coeficiente de correlação de rho de Spearman e a análise multivariada de correlação canônica. Os resultados da pesquisa confirmaram que quanto mais uma organização estrutura-se para a gestão ambiental mais suas práticas ambientais evidenciam-se, da mesma forma, quanto mais uma organização envolve-se com práticas ambientais mais sua estruturação organizacional voltada à gestão ambiental torna-se evidente.
26

Transfer learning applied to a deep learning system for cardiac abnormality classification in electrocardiograms / Överföringsinlärning tillämpad på ett system för djupinlärning för klassificering av hjärtfel i elektrokardiogram.

Campoy Rodriguez, Adrian January 2022 (has links)
Cardiovascular diseases are a leading cause of death globally. Early diagnosis and treatment is of prime importance to prevent or mitigate health complications. Electrocardiogram (ECG) is a standard test modality used for early diagnosis of arrhythmias. The standard ECG uses 12 leads (i.e., 12 different views of the electrical activity of the heart). However, it is not always possible to perform a standard 12-lead ECG, for instance, in certain emergency situations. Such devices used in emergency situations are able to measure only a subset of leads. Although it is a simpler way of recording ECG, it comes at the cost of losing some information. The project presented in this thesis applies three different models based on canonical correlation analysis (CCA) to perform transfer learning from 12-lead ECGs to improve performance when only a subset of leads is available. The models used were linear canonical correlation analysis, deep canonical correlation analysis (DCCA) and deep canonically correlated bidirectional long short-term memory networks (DCC-BiLSTMs). These models are compared to each other using different configurations to study their performance on ECG data. Linear canonical correlation analysis performed better than its more complex variants, DCCA and DCC-BiLSTMs. With this method, it was possible to improve performance on ECG classification when using two, three, four and six leads in a computationally efficient way. / Hjärt- och kärlsjukdomar är den främsta dödsorsaken i världen. Tidig diagnos och behandling är av största vikt för att förhindra ytterligare och allvarliga hälsoproblem. Elektrokardiogram (EKG) är den standardmetod som används för tidig diagnos av arytmier. Standardförfarandet inom EKG använder sig av 12 avledningar (dvs. 12 olika vyer av hjärtats elektriska aktivitet). Det är dock inte alltid möjligt att utföra ett standard-EKG med 12 ledningar, vilket t.ex. förekommer i vissa nödsituationer. I dessa fall kan utrustning som gör det möjligt att ta fram ett 12-ledars EKG inte vara tillgänglig av flera olika skäl, och därför används andra apparater som kan mäta endast en delmängd av ledningarna för tidig diagnostik. Även om det är ett enklare sätt att utföra ett EKG, innebär det att man förlorar en del information. I det projekt som presenteras i detta dokument används tre olika modeller baserade på kanonisk korrelationsanalys (CCA) för att utföra överföringsinlärning från 12-ledars EKG för att förbättra prestanda när endast en delmängd av avledningar används. De modeller som användes var linjär kanonisk korrelationsanalys, djup kanonisk korrelationsanalys (DCCA) och djupa kanoniskt korrelerade bidirektionella långtidsminnesnätverk (DCCBiLSTMs). Dessa modeller jämförs med varandra med hjälp av olika konfigurationer för att studera deras prestanda på EKG-data. Linjär kanonisk korrelationsanalys presterade bättre än dess mer komplexa varianter, DCCA och DCC-BiLSTMs. Med denna metod var det möjligt att förbättra prestandan för klassificering av EKG när man använder två, tre, fyra och sex ledningar på ett beräkningseffektivt sätt.
27

The Relationships Among Perceived Effectiveness of Network-Building Training Approaches, Extent of Advice Networks, and Perceived Individual Job Performance Among Employees in a Semiconductor Manufacturing Company in Korea

Hwang, Sun Ok 25 August 2010 (has links)
No description available.
28

類典型相關分析及其在 免試入學上採計成績之研究 / A canonical correlation analysis type approach to model a criterion for enrolling high school students

卓惠敏, Cho, Hui Min Unknown Date (has links)
實施十二年國民基本教育,目的是為促進學生五育均衡發展,兼顧國中學習品質及日常生活表現。由於各校對成績的評分標準與評分方式皆不相同,因此如何使在校成績採計達到公平性將成為一項重要的問題。 戴岑熹(2011) 考慮了國中在校綜合學科分數與基測總分間的相關性,以決定在校各學科的權重。而本研究延伸其概念與方法,將基測各科量尺分數考慮進來,於在校綜合學科分數與基測綜合量尺分數的關聯性最密切的情況下,分析各學科權重的取決方式,希望能找出較理想的模式來代表學生在校三年的整體學習表現與成果,以做為免試升學採計在校成績的參考與依據。 本文的研究方法是運用典型相關分析的理論,但因權重的限制條件與傳統典型相關分析的要求不同,因此,便將其命名為「類典型相關分析」。在類典型相關分析中,我們證明了在校各學科分數及基測各科量尺分數的最佳權重,可先透過典型相關分析求得典型相關向量,若有必要的話,使用Rao-Ghangurad 方法加以修正,最後,再將所獲得的非負典型相關向量正規化,即可獲得所要的結果,這是一個求最佳權重向量極便捷的途徑。在實例分析方面,我們發現了一個有趣的現象,即在校學科分數與基測考科量尺分數的最佳權重向量相當接近,即名稱相同的學科與考科幾乎有相同的權重。在比較了幾個權重分配方式不同的在校綜合學科分數後,我們也發現一般學校常用的等加權模式,其表現結果也頗優異。 / The purpose of implementing the twelve-year compulsory education is to promote the balanced development of learning in students, taking into account their learning quality and normal daily performances in school. As the evaluation standard and method vary among schools, achieving fairness in calculating in-school grades has become an important issue. Dai (2011) considered the correlations between the scores of in-school academic performance and the total score of the BCTEST for junior high schools, which decided to the weightings of all learning subjects. This study extended his concept and method, and took into account the scale scores of all learning subjects. In the closest case of the weightings of all learning subjects and find out the correlations between the scores of in-school academic performance and the BCTEST, and analyse the weightings of all learning subjects. We hope the study can find a better approach that can not only reflect students’ learning situations and achievements for the three years in school but also provide a reference for the evaluation of entering senior high schools without entrance examinations. The research method in this paper employs the theory of canonical correlation analysis.However, due to that fact that weight restrictions are different from the requirements of canonical correlation analysis, it is named as the canonical correlation analysis type approach. In the canonical correlation analysis type approach, we proved that the optimal weights for school subject score and test subject score scales can be obtained by finding the canonical correlation vectors using canonical correlation analysis. Then the Rao-Ghangurad method can further be used for amending, if needed. Finally, the nonnegative canonical correlation vectors generated would be normalized to get the desired result. It is an extremely convenient way to obtain the optimal weight vector. In the case study, we found an interesting phenomenon as follows: When the optimal weight vectors for school subject score and test subject score scales were very close, subjects and tests of the same name had almost the same weight. After comparing several comprehensive school subject scores of different weight distribution, we also found that the results of the equal weighting model commonly used in schools also showed quite good results.
29

Canonical correlation analysis of aggravated robbery and poverty in Limpopo Province

Rwizi, Tandanai 05 1900 (has links)
The study was aimed at exploring the relationship between poverty and aggravated robbery in Limpopo Province. Sampled secondary data of aggravated robbery of- fenders, obtained from the South African Police (SAPS), Polokwane, was used in the analysis. From empirical researches on poverty and crime, there are some deductions that vulnerability to crime is increased by poverty. Poverty set was categorised by gender, employment status, marital status, race, age and educational attainment. Variables for aggravated robbery were house robbery, bank robbery, street/common robbery, carjacking, truck hijacking, cash-in-transit and business robbery. Canonical correlation analysis was used to make some inferences about the relationship of these two sets. The results revealed a signi cant positive correlation of 0.219(p-value = 0.025) between poverty and aggravated robbery at ve per cent signi cance level. Of the thirteen variables entered into the poverty-aggravated model, ve emerged as sta- tistically signi cant. These were gender, marital status, employment status, common robbery and business robbery. / Mathematical Sciences / M. Sc. (Statistics)
30

多反應變量相關模式於不動產擔保估價之應用

陳俊宏 Unknown Date (has links)
本研究以不動產估價技術規則第19條第7項與第20條之規定,引用相似無關迴歸模式、多變量迴歸模式與典型相關分析等計量模式,對金融機構所做的擔保品估價進行驗證、預測及控制分析。 擔保品估價中會產生兩價,即擔保品的評估市場價格與評估擔保值(價),大部分的人都認為兩價存在一個比率關係。傳統的迴歸分析估價模式係由一組價格影響因素影響一個不動產價格,上述情形是否可能由同一組價格影響因素影響兩個不動產價格?本研究實證結果顯示,在95%統計信賴水準下,有兩個不動產價格受同一組價格因素影響的結果。既然驗證存在同一組價格影響因素影響兩個不動產價格,是否有更具效率的計量估價模式呢?典型相關分析係透過兩組變項之相關關係建構計量模式,除可再度驗證同一組價格影響因素影響兩個不動產價格,並可如同因素分析或主成份分析的功能,對兩組變項各做變項縮減的工作,達到對變項去蕪存菁的效果。 / This thesis is based on Article 19 No 7 and Article 20 of the Real Estate Appraisal Regulation. Seemingly Unrelated Regression Model, Multivariate Regression Model and Econometric Model and so on econometric model are applied. In addition, collateral valuations done by financial institutions are verified, predicted and analyzed. In collateral valuations, there are two-value references: assessed market value and assessed accommodation value. Majority believe that there is a ratio between these two values. The traditional regression analysis of the valuation model is having one set of pricing factors to have impact on the real estate price. However, is it possible that one set of pricing factors will affect two real estate prices? The findings approve that, under statistical confidence level with 95%, more than two real estate prices can be influenced by one set of pricing factors. Further more, this thesis also examines if there are other econometric valuation models to be applied? The canonical correlation analysis is to build a calculation model to analyze correlation between two variables. Other than examining one set of pricing factors can influence two real estate prices, this analysis also provides a similar function of the factor analysis or principal analysis to reduce variables caused by two sets of variable.

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