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Search Results: 1 - 10 of 11445 matches for " Scarpel Rodrigo Arnaldo "
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Detec??o de fraudes na distribui??o de energia elétrica utilizando support vector machine
Silva,Vinícius Dornela; Scarpel,Rodrigo Arnaldo;
Investiga??o Operacional , 2007,
Abstract: several economics sectors are exposed to fraud made by their own customers. at the electrician distribution segment is not different. several techniques in statistical fields were developed to detect illegal activities, relied in observation classification. the empiric events modeling always become a challenge to get solution in engineering projects. the solution is achieved using a induction process to built a system able to bring up the answer of a previously observed event. the linear discriminate analysis is the quantitative method most used. recently, an alternative approach arises: the support vector machine (svm). this paper objectives is train and test a model built using svm to point out the customers that are performing frauds given the customers company (an electrician distribution) data base, doing a efficiency and quality confrontation vis-à-vis the linear discriminate analysis.
Otimiza??o na forma??o de agrupamentos em problemas de composi??o de especialistas
Scarpel, Rodrigo Arnaldo;Milioni, Armando Zeferino;
Pesquisa Operacional , 2007, DOI: 10.1590/S0101-74382007000100005
Abstract: estimation of real-valued functions from a finite set of samples is a central problem in applied statistics. many different approaches to deal with this problem were proposed as the least-squares method by gauss, the least-modulus method by laplace, and more recently the usage of neural networks, support vector machines, mixture of local expert models, amongst others. we addressed the issues mixture of local expert models (mlem) and clustering optimization, which congregates exploratory analysis, data mining and mathematical modeling in the same technique, used, for example, in the development of predictive models. the basic idea of mlem is clustering the points from the entry data set, and then different modeling techniques are applied in order to select the best model for each cluster. we proposed a clustering optimization procedure as a way to improve the performance on both the fitting of the models and their usage in forecasting.
Utiliza??o conjunta de modelagem econométrica e otimiza??o em decis?es de concess?o de crédito
Scarpel, Rodrigo Arnaldo;Milioni, Armando Zeferino;
Pesquisa Operacional , 2002, DOI: 10.1590/S0101-74382002000100004
Abstract: we use a logit model such as the one developed by scarpel & milioni (2001), designed to forecast corporations bankruptcy, together with an integer programming model developed by gehrlein & wagner (1997). we aim at supporting decisions of credit concession considering the corporation's solvency probability estimate and minimizing the sum of opportunity and failure to pay costs. as we show, the conjoint utilization of both models eliminates limitations found in each of them, when used in isolation.
Utiliza o conjunta de modelagem econométrica e otimiza o em decis es de concess o de crédito
Scarpel Rodrigo Arnaldo,Milioni Armando Zeferino
Pesquisa Operacional , 2002,
Abstract: Utilizamos um modelo econométrico do tipo Logit como o desenvolvido por Scarpel & Milioni (2001), concebido para atuar em previs o de insolvência de empresas, em conjunto com o modelo de programa o linear inteira desenvolvido por Gehrlein & Wagner (1997). O objetivo é o de dar suporte a decis es de concess o de crédito em fun o da estimativa da probabilidade de solvência de empresas, de forma a minimizar a soma dos custos de oportunidade e inadimplência. Mostramos que a utiliza o conjunta desses modelos possibilita a elimina o das limita es encontradas quando eles s o utilizados isoladamente no auxílio às decis es de concess o de crédito.
Importancia das características na precifica??o de veículos nacionais
Resende, Camilo Brand?o de;Scarpel, Rodrigo Arnaldo;
Produ??o , 2009, DOI: 10.1590/S0103-65132009000200010
Abstract: the market of consumer goods is consisted of heterogeneous products which can be viewed as a union of attributes or characteristics. quantifying the value of these characteristics can help in the creation of a pricing rule, allowing, for example, pricing a product which is not available, and helping in the estimates of its demand. the purpose of this work is to use the theory of hedonic price to determine empirically the value of characteristics, as well as their relative importance, in the price of brazilian vehicles. the model was obtained using data regarding 150 national vehicles and a linear hedonic function, which coefficients were estimated by ordinary least squares. it can be concluded that the engine power is the factor which has the greatest impact on a vehicle price, followed by the luxury level and the brand.
Insolvency and crisis: a study of the determinants of the exit of airlines in the Brazilian market [paper in Portuguese]
Rodrigo Ferreira de Oliveira,Rodrigo Arnaldo Scarpel,Alessandro V. M. Oliveira
Journal of Transport Literature , 2008,
Abstract: This paper constitutes the first attempt in the literature to identify the determinants of the bankruptcy of the major legacy carriers in Brazil within the period of 1983 to 2003. The airlines under analysis here were Varig, Vasp and Transbrasil. The situation of the industry as a whole was also analyzed. The econometric study of the bankruptcy airlines allowed a better understanding of the causes of the exit of an airline in the market. An adequate prediction of those leaves allows the regulatory authorities to anticipate the actions that will soften these effects, especially regarding the disruption of the service. To determine the airlines’ bankruptcy conditions three financial indexes had been analyzed: Debt Ratio (EG), Asset Turn (GA), and Return on Assets Before Interest and Income Taxes (ROA AJIR). An index PS, that reflects the airlines’ solvency, was also analyzed. The PS index is based on the other indexes EG, GA, and ROA.
Insolvency and Crisis: A Study of the Determinants of the Exit of Airlines in the Brazilian Market
Rodrigo Oliveira,Rodrigo Scarpel,Alessandro Oliveira
Revista de Literatura dos Transportes , 2008,
Abstract: This paper constitutes the first attempt in the literature to identify the determinants of the bankruptcy of the major legacy carriers in Brazil within the period of 1983 to 2003. The airlines under analysis here were Varig, Vasp and Transbrasil. The situation of the industry as a whole was also analyzed. The econometric study of the bankruptcy airlines allowed a better understanding of the causes of the exit of an airline in the market. An adequate prediction of those leaves allows the regulatory authorities to anticipate the actions that will soften these effects, especially regarding the disruption of the service. To determine the airlines’ bankruptcy conditions three financial indexes had been analyzed: Debt Ratio (EG), Asset Turn (GA), and Return on Assets Before Interest and Income Taxes (ROA AJIR). An index PS, that reflects the airlines’ solvency, was also analyzed. The PS index is based on the other indexes EG, GA, and ROA.[Paper in Portuguese]
Augmented Neural Networks for Modelling Consumer Indebtness
Alexandros Ladas,Jonathan M. Garibaldi,Rodrigo Scarpel,Uwe Aickelin
Computer Science , 2014,
Abstract: Consumer Debt has risen to be an important problem of modern societies, generating a lot of research in order to understand the nature of consumer indebtness, which so far its modelling has been carried out by statistical models. In this work we show that Computational Intelligence can offer a more holistic approach that is more suitable for the complex relationships an indebtness dataset has and Linear Regression cannot uncover. In particular, as our results show, Neural Networks achieve the best performance in modelling consumer indebtness, especially when they manage to incorporate the significant and experimentally verified results of the Data Mining process in the model, exploiting the flexibility Neural Networks offer in designing their topology. This novel method forms an elaborate framework to model Consumer indebtness that can be extended to any other real world application.
ESPECTRO FENOTíPICO DEL SíNDROME DE OVARIO POLIQUíSTICO
Carvajal G,Rodrigo; Herrera G,Cristian; Porcile J,Arnaldo;
Revista chilena de obstetricia y ginecología , 2010, DOI: 10.4067/S0717-75262010000200009
Abstract: background: policystic ovary syndrome (pcos) is a very common endocrine disease in women of reproductive age, of uncertain etiology and heterogeneous clinical presentation. the introduction of the rotterdams consensus criteria generated new phenotypes by incorporating transvaginal ultrasound, thus increasing the heterogenity of pcos. objectives: to determine in a cohort of 102 patients with the diagnosis of pcos the prevalence, clinical, hormonal and metabolic profle according to rotterdam. results: it was determined the phenotype a 62% phenotype b 21%, phenotype c 9% and phenotype d 8% of the patients. the metabolic syndrome was present in 29% of the pcos patients, being it more frequent in the phenotypes a (30%) and b (43%) than c (11%) and d (13%). the 82% of the patients were overweigth, especially in the phenotypes a (88%) and b (90%). also, statistically signifcant differences were observed when comparing the variables score of hirsutism, free androgen index, total testosterone, hdl cholesterol shbg, ovarian volume, total cholesterol, glycemia and ldl cholesterol. there were no signifcant differences between the groups to compare variables such as age, bmi, dhea and triglycerides. conclusion: these fndings indicate that the consensus of rotterdam would agroup different phenotypes in the same syndrome and that it may represent different degrees of severity of the same disease. even though, we do not know if these phenotypes posses the same health risks, therefore it is soon to manage the phenotypes as equal entities.
ESPECTRO FENOTíPICO DEL SíNDROME DE OVARIO POLIQUíSTICO
Rodrigo Carvajal G,Cristian Herrera G,Arnaldo Porcile J
Revista Chilena de Obstetricia y Ginecología , 2010,
Abstract: Antecedentes: El síndrome de ovario poliquístico (SOP) es la endocrinopatía más frecuente en la mujer de edad reproductiva, de etiología incierta y presentación clínica heterogénea. Su diagnóstico y defnición es aún controversial. La introducción de los criterios del Consenso de Rotterdam generó nuevos fenotipos al incorporar la ecografía transvaginal como elemento diagnóstico, aumentando aún más la heterogeneidad del síndrome. Objetivo: Determinar en una cohorte consecutiva de 102 pacientes con diagnóstico de SOP, su frecuencia, las características clínicas, hormonales y metabólicas, de los cuatro fenotipos posibles según Rotterdam. Resultados: Fenotipo A 62%, Fenotipo B 21%, Fenotipo C 9% y Fenotipo D 8%. El síndrome metabólico se presentó en 29% de las pacientes, siendo mayor en los fenotipos A (30%) y B (43%) que en los fenotipos C (11%) y D (13%). El 82% presentaba sobrepeso, siendo signifcativamente mayor en los fenotipos A (88%) y B (90%). Hubo diferencias signifcativas al comparar las variables puntaje de hir-sutismo, SHBG, testosterona total, IAL, volumen ovárico, colesterol total, colesterol HDL, colesterol LDL y glicemia en ayuno. No existieron diferencias signifcativas entre los grupos al comparar las variables edad, IMC, DHEA-SO4 y triglicéridos. Conclusión: El consenso de Rotterdam agruparía a diferentes fenotipos en un mismo síndrome, que podrían representar distintos grados de severidad de una misma enfermedad. Se desconoce si estos fenotipos poseen los mismos riesgos a largo plazo y sería apresurado tratarlos como una misma entidad. Background: Policystic ovary syndrome (PCOS) is a very common endocrine disease in women of reproductive age, of uncertain etiology and heterogeneous clinical presentation. The introduction of the Rotterdams Consensus criteria generated new phenotypes by incorporating transvaginal ultrasound, thus increasing the heterogenity of PCOS. Objectives: To determine in a cohort of 102 patients with the diagnosis of PCOS the prevalence, clinical, hormonal and metabolic profle according to Rotterdam. Results: It was determined the Phenotype A 62% Phenotype B 21%, Phenotype C 9% and Phenotype D 8% of the patients. The metabolic syndrome was present in 29% of the PCOS patients, being it more frequent in the phenotypes A (30%) and B (43%) than C (11%) and D (13%). The 82% of the patients were overweigth, especially in the phenotypes A (88%) and B (90%). Also, statistically signifcant differences were observed when comparing the variables score of hirsutism, free androgen index, total testosterone, HDL cholesterol SHBG, o
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