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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

Using nuclear receptor interactions as biomarkers for metabolic syndrome

Hettne, Kristina January 2003 (has links)
Metabolic syndrome is taking epidemic proportions, especially in developed countries. Each risk factor component of the syndrome independently increases the risk of developing coronary artery disease. The risk factors are obesity, dyslipidemia, hypertension, diabetes type 2, insulin resistance, and microalbuminuria. Nuclear receptors is a family of receptors that has recently received a lot of attention due to their possible involvement in metabolic syndrome. Putting the receptors into context with their co-factors and ligands may reveal therapeutic targets not found by studying the receptors alone. Therefore, in this thesis, interactions between genes in nuclear receptor pathways were analysed with the goal of investigating if these interactions can supply leads to biomarkers for metabolic syndrome. Metabolic syndrome donor gene expression data from the BioExpressä, database was analysed with the APRIORI algorithm (Agrawal et al. 1993) for generating and mining association rules. No association rules were found to function as biomarkers for metabolic syndrome, but the resulting rules show that the data mining technique successfully found associations between genes in signaling pathways.
22

Methodology For Generating High-Confidence Cost-Sensitive Rules For Classification

Bakshi, Arjun 21 October 2013 (has links)
No description available.
23

Parallel Mining of Association Rules Using a Lattice Based Approach

Thomas, Wessel Morant 01 January 2009 (has links)
The discovery of interesting patterns from database transactions is one of the major problems in knowledge discovery in database. One such interesting pattern is the association rules extracted from these transactions. Parallel algorithms are required for the mining of association rules due to the very large databases used to store the transactions. In this paper we present a parallel algorithm for the mining of association rules. We implemented a parallel algorithm that used a lattice approach for mining association rules. The Dynamic Distributed Rule Mining (DDRM) is a lattice-based algorithm that partitions the lattice into sublattices to be assigned to processors for processing and identification of frequent itemsets. Experimental results show that DDRM utilizes the processors efficiently and performed better than the prefix-based and partition algorithms that use a static approach to assign classes to the processors. The DDRM algorithm scales well and shows good speedup.
24

Elektroninių aukcionų kūrimas / Development of e-auctions

Zelenkauskas, Artūras 09 July 2011 (has links)
. Informacinės technologijos, tokios kaip Internetas ir elektroninė komercija, radikaliai pakeitė būdus, kaip keistis informacija ar vykdyti įvairius atsiskaitymus. Sparčiai besivystančios informacinės technologijos neaplenkė ir verslo, kuriam suteikė naujų galimybių didinant konkurencingumą. Per pastaruosius keletą metų ypač išpopuliarėjo elektroninės komercijos šaka – elektroniniai aukcionai, kuri dar labiau paskatino verslą keltis į elektroninę erdvę. Aukciono valdymas yra sudėtingas. Vienas iš svarbiausių konkurencingumo veiksnių yra kaina, kuriai nustatyti įmonė taiko įvairias kainodaros taisykles. Aukcionas tai dinaminės kainodaros būdas, kuris leidžia įmonei ir klientui rasti pačią tinkamiausią sandorio kainą. Tinkamai valdydamos ir kaupdamos verslo taisykles, įmonės galėtų gauti didesnį pelną, greičiau parduoti turimas prekes. Elektroniniai aukcionai, paremti turinio valdymo principu ir norimų taisyklių sudarymu galėtų prisidėti prie verslo efektyvumo didinimo, t.y. kokiu būdu įmonės galėtų integruoti elektroninio aukciono metodą į savo informacines sistemas. Atlikta įvairių aukciono metodų teorinių veikimo principų analizė, kuri leido apibendrinti visus metodus, išskiriant ir palyginant pagrindines jų taisykles. Darbe atlikta sukurtų elektroninių aukcionų informacinių sistemų analizė ir jų kūrimo principai, kurie leido apibendrinti pagrindines naudojamas taisykles. Atliktas eksperimentinis tyrimas, kurio metu koreliacinės analizės metodu buvo rasti ryšiai tarp... [toliau žr. visą tekstą] / Modern business is increasingly looking for more effective marketing techniques, not only in domestic but also international markets. Over the past few years, online auctions became very popular, which encouraged the business move to Internet. Online auctions based on content management principles and rules could help to increase business efficiency. The operating principles of online auctions are reviewed and analyzed in this graduation paper. Online auction systems diversity is analyzed in analytical part of the work. Four different auction systems were analyzed and their main development principles (rules) were summarized. Considering to analysis part online auction model that can help companies increase sales and profits through the auction approach was designed. Experimental study has been made to verify the functionality of the proposed model. Data – jewelry – listings were collected from the world's largest online auction eBay. Quantitative and qualitative data was analyzed; the results are shown in graphs and tables. The final result was derived under the rules of price categories to choose the basic parameters of an auction: the starting price, auction duration and reliability. New benefit option was introduced, which enabled to compare and evaluate the obtained rules. Different methods were used to generate and evaluate auction rules. One of them is self organizing map (SOM). Its aid was used to classify the data. The statistical analysis method was used to evaluate... [to full text]
25

Visualizing association rules in hierarchical groups

Hahsler, Michael, Karpienko, Radoslaw 07 May 2016 (has links) (PDF)
Association rule mining is one of the most popular data mining methods. However, mining association rules often results in a very large number of found rules, leaving the analyst with the task to go through all the rules and discover interesting ones. Sifting manually through large sets of rules is time consuming and strenuous. Although visualization has a long history of making large amounts of data better accessible using techniques like selecting and zooming, most association rule visualization techniques are still falling short when it comes to large numbers of rules. In this paper we introduce a new interactive visualization method, the grouped matrix representation, which allows to intuitively explore and interpret highly complex scenarios. We demonstrate how the method can be used to analyze large sets of association rules using the R software for statistical computing, and provide examples from the implementation in the R-package arulesViz. (authors' abstract)
26

Data mining em banco de dados de eletrocardiograma / Data mining in electrocardiogram databases

Ferreira, José Alves 23 April 2014 (has links)
Neste estudo, foi proposta a exploração de um banco de dados, com informações de exames de eletrocardiogramas (ECG), utilizado pelo sistema denominado Tele-ECG do Instituto Dante Pazzanese de Cardiologia, aplicando a técnica de data mining (mineração de dados) para encontrar padrões que colaborem, no futuro, para a aquisição de conhecimento na análise de eletrocardiograma. A metodologia proposta permite que, com a utilização de data mining, investiguem-se dados à procura de padrões sem a utilização do traçado do ECG. Três pacotes de software (Weka, Orange e R-Project) do tipo open source foram utilizados, contendo, cada um deles, um conjunto de implementações algorítmicas e de diversas técnicas de data mining, além de serem softwares de domínio público. Regras conhecidas foram encontradas (confirmadas pelo especialista médico em análise de eletrocardiograma), evidenciando a validade dessa metodologia. / In this study, the exploration of electrocardiograms (ECG) databases, obtained from a Tele-ECG System of Dante Pazzanese Institute of Cardiology, has been proposed, applying the technique of data mining to find patterns that could collaborate, in the future, for the acquisition of knowledge in the analysis of electrocardiograms. The proposed method was to investigate the data looking for patterns without the use of the ECG traces. Three Data-mining open source software packages (Weka, Orange and R - Project) were used, containing, each one, a set of algorithmic implementations and various data mining techniques, as well as being a public domain software. Known rules were found (confirmed by medical experts in electrocardiogram analysis), showing the validity of the methodology.
27

Apriori Sets And Sequences: Mining Association Rules from Time Sequence Attributes

Pray, Keith A 06 May 2004 (has links)
We introduce an algorithm for mining expressive temporal relationships from complex data. Our algorithm, AprioriSetsAndSequences (ASAS), extends the Apriori algorithm to data sets in which a single data instance may consist of a combination of attribute values that are nominal sequences, time series, sets, and traditional relational values. Datasets of this type occur naturally in many domains including health care, financial analysis, complex system diagnostics, and domains in which multi-sensors are used. AprioriSetsAndSequences identifies predefined events of interest in the sequential data attributes. It then mines for association rules that make explicit all frequent temporal relationships among the occurrences of those events and relationships of those events and other data attributes. Our algorithm inherently handles different levels of time granularity in the same data set. We have implemented AprioriSetsAndSequences within the Weka environment and have applied it to computer performance, stock market, and clinical sleep disorder data. We show that AprioriSetsAndSequences produces rules that express significant temporal relationships that describe patterns of behavior observed in the data set.
28

"Generalização de regras de associação" / Generalization of association rules

Marcos Aurélio Domingues 27 April 2004 (has links)
Mineração de Dados é um processo de natureza iterativa e interativa responsável por identificar padrões em grandes conjuntos de dados, objetivando extrair conhecimento válido, útil e inovador a partir desses. Em Mineração de Dados, Regras de Associação é uma técnica que consiste na identificação de padrões intrínsecos ao conjunto de dados. Essa técnica tem despertado grande interesse nos pesquisadores de Mineração de Dados e nas organizações, entretanto, a mesma possui o inconveniente de gerar grande volume de conhecimento no formato de regras, dificultando a análise e interpretação dos resultados pelo usuário. Nesse contexto, este trabalho tem como objetivo principal generalizar e eliminar Regras de Associação não interessantes e/ou redundantes, facilitando, dessa maneira, a análise das regras obtidas com relação à compreensibilidade e tamanho do conjunto de regras. A generalização das Regras de Associação é realizada com o uso de taxonomias. Entre os principais resultados deste trabalho destacam-se a proposta e a implementação do algoritmo GART e do módulo computacional RulEE-GAR. O algoritmo GART (Generalization of Association Rules using Taxonomies - Generalização de Regras de Associação usando Taxonomias) utiliza taxonomias para generalizar Regras de Associação. Já o módulo RulEE-GAR, além de facilitar o uso do algoritmo GART durante a identificação de taxonomias e generalização de regras, provê funcionalidades para analisar as Regras de Associação generalizadas. Os experimentos realizados, neste trabalho, mostraram que o uso de taxonomias na generalização de Regras de Associação pode reduzir o volume de um conjunto de regras. / Data Mining refers to the process of finding patterns in large data sets. The Association Rules in Data Mining try to identify intrinsic behaviors of the data set. This has motivated researchers of Data Mining and organizations. However, the Association Rules have the inconvenient of generating a great amount of knowledge in the form of rules. This makes the analysis and interpretation of the results difficult for the user. Taking this into account, the main objective of this research is the generalization and elimination of non-interesting and/or redundant Association Rules. This facilite the analysis of the rules with respect to the compreensibility and the size of the rule set. The generalization is realized using taxonomies. The main results of this research are the proposal and the implementation of the algorithm GART and of the computational module RulEE-GAR. The algorithm GART (Generalization of Association Rules using Taxonomies) uses taxonomies to generalize Association Rules. The module RulEE-GAR facilitates the use of the algorithm GART in the identification of taxonomies and generalization of rules and provide functionalities to the analysis of the generalized Association Rules. The results of experiments showed that the employment of taxonomies in the generalization of Association Rules can reduce the size of a rule set.
29

Multi-Purpose Boundary-Based Clustering on Proximity Graphs for Geographical Data Mining

Lee, Ickjai Lee January 2002 (has links)
With the growth of geo-referenced data and the sophistication and complexity of spatial databases, data mining and knowledge discovery techniques become essential tools for successful analysis of large spatial datasets. Spatial clustering is fundamental and central to geographical data mining. It partitions a dataset into smaller homogeneous groups due to spatial proximity. Resulting groups represent geographically interesting patterns of concentrations for which further investigations should be undertaken to find possible causal factors. In this thesis, we propose a spatial-dominant generalization approach that mines multivariate causal associations among geographical data layers using clustering analysis. First, we propose a generic framework of multi-purpose exploratory spatial clustering in the form of the Template-Method Pattern. Based on an object-oriented framework, we design and implement an automatic multi-purpose exploratory spatial clustering tool. The first instance of this framework uses the Delaunay diagram as an underlying proximity graph. Our spatial clustering incorporates the peculiar characteristics of spatial data that make space special. Thus, our method is able to identify high-quality spatial clusters including clusters of arbitrary shapes, clusters of heterogeneous densities, clusters of different sizes, closely located high-density clusters, clusters connected by multiple chains, sparse clusters near to high-density clusters and clusters containing clusters within O(n log n) time. It derives values for parameters from data and thus maximizes user-friendliness. Therefore, our approach minimizes user-oriented bias and constraints that hinder exploratory data analysis and geographical data mining. Sheer volume of spatial data stored in spatial databases is not the only concern. The heterogeneity of datasets is a common issue in data-rich environments, but left open by exploratory tools. Our spatial clustering extends to the Minkowski metric in the absence or presence of obstacles to deal with situations where interactions between spatial objects are not adequately modeled by the Euclidean distance. The genericity is such that our clustering methodology extends to various spatial proximity graphs beyond the default Delaunay diagram. We also investigate an extension of our clustering to higher-dimensional datasets that robustly identify higher-dimensional clusters within O(n log n) time. The versatility of our clustering is further illustrated with its deployment to multi-level clustering. We develop a multi-level clustering method that reveals hierarchical structures hidden in complex datasets within O(n log n) time. We also introduce weighted dendrograms to effectively visualize the cluster hierarchies. Interpretability and usability of clustering results are of great importance. We propose an automatic pattern spotter that reveals high level description of clusters. We develop an effective and efficient cluster polygonization process towards mining causal associations. It automatically approximates shapes of clusters and robustly reveals asymmetric causal associations among data layers. Since it does not require domain-specific concept hierarchies, its applicability is enhanced. / PhD Doctorate
30

Temporal Data Mining with a Hierarchy of Time Granules

Wu, Pei-Shan 28 August 2012 (has links)
Data mining techniques have been widely applied to extract desirable knowledge from existing databases for specific purposes. In real-world applications, a database usually involves the time periods when transactions occurred and exhibition periods of items, in addition to the items bought in the transactions. To handle this kind of data, temporal data mining techniques are thus proposed to find temporal association rules from a database with time. Most of the existing studies only consider different item lifespans to find general temporal association rules, and this may neglect some useful information. For example, while an item within the whole exhibition period may not be a frequent one, it may be frequent within part of this time. To deal with this, the concept of a hierarchy of time is thus applied to temporal data mining along with suitable time granules, as defined by users. In this thesis, we thus handle the problem of mining temporal association rules with a hierarchy of time granules from a temporal database, and also propose three novel mining algorithms for different item lifespan definitions. In the first definition, the lifespan of an item in a time granule is calculated from the first appearance time to the end time in the time granule. In the second definition, the lifespan of an item in a time granule is evaluated from the publication time of the item to the end time in the time granule. Finally, in the third definition, the lifespan of an item in a time granule is measured by its entire exhibition period. The experimental results on a simulation dataset show the performance of the three proposed algorithms under different item lifespan definitions, and compare the mined temporal association rules with and without consideration of the hierarchy of time granules under different parameter settings.

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