Linda Ho | Universidade de São Paulo (original) (raw)

Papers by Linda Ho

Sustainability, 2020

This study focused on verifying whether the emission of air pollutants in São Paulo increases the... more This study focused on verifying whether the emission of air pollutants in São Paulo increases the costs and number of hospitalizations for respiratory diseases in Brazil. Data on pollutant emissions, hospitalizations, and hospital costs were collected from 2008 to 2017 and correlated with air quality standards. The results showed that the concentration of particulate matter increased each year during the study period and was highly correlated with hospitalizations due to respiratory diseases. Ozone (O3) was within the quality standard throughout the study period but registered an increase in the mean and a positive correlation with hospitalizations due to respiratory diseases. The carbon monoxide (CO), sulfur dioxide (SO2), and nitrogen dioxide (NO2) levels were within the quality standards throughout the study period with a decrease in the last years studied, but showed a positive correlation with hospitalizations due to respiratory diseases. The pollutant emissions and hospitaliza...

RAM. Revista de Administração Mackenzie

RESUMO Este trabalho integra os conceitos de Planejamento Estratégico e da Teoria das Filas para ... more RESUMO Este trabalho integra os conceitos de Planejamento Estratégico e da Teoria das Filas para dar suporte à formulação e avaliação de estratégias viáveis para a gestão de serviços bancários oferecidos por caixas automáticos (ATM). Além disso, obteve-se um referencial prático valioso para a compreensão de como surge uma estratégia emergente. Este estudo utilizou informações sobre o comportamento dos usuários de caixas automáticos de um dos maiores bancos de varejo do Brasil e os atualizou de acordo com as mudanças da regulamentação bancária ocorrida em 2001 em função do racionamento de energia elétrica. De uma forma geral, foram identificadas duas linhas estratégicas opostas, representadas pelos bancos Bradesco e Itaú, respectivamente, primeiro e segundo maior banco privado brasileiro, sobre o tratamento oferecido aos seus clientes nas salas de auto-atendimento.

VII Seminário Internacional da LARES, 2007

Produto & Produção, 2008

Apresentamos um modelo apropriado para a análise estatística de dados pareados que pode ser encar... more Apresentamos um modelo apropriado para a análise estatística de dados pareados que pode ser encarado como uma generalização do teste t pareado para a comparação de médias. Ele é suficientemente geral a ponto de permitir a inclusão de covariáveis e respostas omissas. Ilustramos o procedimento com a análise da evolução da gestão ambiental de empresas basileiras baseada em questionários de auto-avaliação respondido por empresas em 1996 e 2001.

Anais do Encontro Nacional de Engenharia de Produção, 2018

Quality and Reliability Engineering International, 2015

Journal of Manufacturing Technology Management, 2014

Purpose – The purpose of this paper is to assess the status of Six Sigma's status in Brazilia... more Purpose – The purpose of this paper is to assess the status of Six Sigma's status in Brazilian companies and understand the integration of this program with other quality management approaches. Additionally, the critical success factors (CSFs) for Six Sigma implementation and primary Six Sigma program characteristics were identified. Finally, the results of the used of Six Sigma were analysed. Design/methodology/approach – An extensive literature review illustrates the primary Six Sigma characteristics and its relationship with other quality approaches. The research methodology encompasses survey development and statistical analyses. Questionnaires are distributed to 1,000 large firms in the manufacturing and service industries in Brazil. Altogether, a total of 198 firms, of which 46 companies adopted the Six Sigma program, participated in this study. Findings – The results suggest a synergic and incremental pattern of quality model implementation. The study reveals that compani...

International Journal of Quality & Reliability Management, 2006

PurposeTo present the bootstrap procedure to correct biases in maximum likelihood estimator of me... more PurposeTo present the bootstrap procedure to correct biases in maximum likelihood estimator of mean time to failure (MTTF) and percentiles in a Weibull regression model.Design/methodology/approachA reliability model is described by a Weibull regression model with parameters being estimated by maximum likelihood method and they will be used estimate other quantities of interest as MTTF or percentiles. When a small sample is employed it is known that the estimates of these quantities are biased. A simulation study varying sample size, censored mechanisms, allocation mechanisms and levels of censored data are designed to quantify these biases.FindingsThe bootstrap procedure corrects the biased maximum likelihood estimates of MTTF and percentiles.Practical implicationsA minor sample may be required if the bootstrap procedure is required to produce estimator of the quantities as MTTF and percentiles.Originality/valueThe employment of bootstrap procedure to quantify the biases since analy...

European Journal of Operational Research, 2010

Engineering Optimization, 2010

The procedure for online process control by attributes consists of inspecting a single item at ev... more The procedure for online process control by attributes consists of inspecting a single item at every m produced items. It is decided on the basis of the inspection result whether the process is in-control (the conforming fraction is stable) or out-of-control (the conforming fraction is decreased, for example). Most articles about online process control have cited the stoppage of the production process for an adjustment when the inspected item is non-conforming (then the production is restarted in-control, here denominated as corrective adjustment). Moreover, the articles related to this subject do not present semi-economical designs (which may yield high quantities of non-conforming items), as they do not include a policy of preventive adjustments (in such case no item is inspected), which can be more economical, mainly if the inspected item can be misclassified. In this article, the possibility of preventive or corrective adjustments in the process is decided at every m produced item. If a preventive adjustment is decided upon, then no item is inspected. On the contrary, the m-th item is inspected; if it conforms, the production goes on, otherwise, an adjustment takes place and the process restarts in-control. This approach is economically feasible for some practical situations and the parameters of the proposed procedure are determined minimizing an average cost function subject to some statistical restrictions (for example, to assure a minimal level—fixed in advance—of conforming items in the production process). Numerical examples illustrate the proposal.

Communications in Statistics - Theory and Methods, 2013

ABSTRACT The procedure of on-line process control for variables proposed by Taguchi consists of i... more ABSTRACT The procedure of on-line process control for variables proposed by Taguchi consists of inspecting the mth item (a single item) of every m items produced and deciding, at each inspection, whether the mean value is increased or not. If the value of the monitored statistic is outside of the control limits, one decides the process is out-of-control and the production is stopped for adjustment; otherwise, it continues. In this article, a variable sampling interval (with a longer L and a shorter m ≤ L) chart with two set of limits is used. These limits are the warning (±W) and the control (±C), where W ≤ C. The process is stopped for adjustment when an observation falls outside of the control limits or a sequence of h observations falls between the warning limits and the control limits. The longer sample interval is used after an adjustment or when an observation falls inside the warning limits; otherwise, the short sampling interval is used. The properties of an ergodic Markov chain are used to evaluate the time (in units) that the process remains in-control and out-of-control, with the aim of building an economic–statistical model. The parameters (the sampling intervals m and L, the control limits W and C and the length of run h) are optimized by minimizing the cost function with constraints on the average run lengths (ARLs) and the conformity fraction. The performance of the current proposal is more economical than the decision taken based on a sequence of length h = 1, L = m, and W = C, which is the model employed in earlier studies. A numerical example illustrates the proposed procedure.

Communications in Statistics - Theory and Methods, 2003

... A statistical model for shelf life estimation using sensory evaluations scores. Auteur(s) / A... more ... A statistical model for shelf life estimation using sensory evaluations scores. Auteur(s) / Author(s). FREITAS Marta Afonso (1) ; BORGES Wagner (2) ; LINDA LEE HO (3) ; Affiliation(s) du ou des auteurs / Author(s) Affiliation(s). ... Distribution temporelle. ; Loi Weibull. ; ...

International Journal of Quality & Reliability Management, 2004

Sensory evaluations to determine the shelf life of food products are routinely conducted in food ... more Sensory evaluations to determine the shelf life of food products are routinely conducted in food experimentation as a part of each product development program, whether it includes a new product, product improvement or a change in type or specification of an ingredient. In such experiments, trained panelists are asked to judge food attributes by reference to a scale of numbers. The “failure time” associated with a product unit under test is usually defined as the time required to reach a cut‐off point previously defined by the food company. Important issues associated with the planning and execution of this kind of testing are total sampling size, frequency of sample withdrawals, panel design, and statistical analysis of the panel data, to list a few. Different approaches have been proposed for the analysis of this kind of data. In particular, Freitas et al. proposed an alternative model based on a dichotomization of the score data and a Weibull as the underlying distribution for the...