906 resultados para Exploratory statistical data analysis


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The paper presents some contemporary approaches to spatial environmental data analysis. The main topics are concentrated on the decision-oriented problems of environmental spatial data mining and modeling: valorization and representativity of data with the help of exploratory data analysis, spatial predictions, probabilistic and risk mapping, development and application of conditional stochastic simulation models. The innovative part of the paper presents integrated/hybrid model-machine learning (ML) residuals sequential simulations-MLRSS. The models are based on multilayer perceptron and support vector regression ML algorithms used for modeling long-range spatial trends and sequential simulations of the residuals. NIL algorithms deliver non-linear solution for the spatial non-stationary problems, which are difficult for geostatistical approach. Geostatistical tools (variography) are used to characterize performance of ML algorithms, by analyzing quality and quantity of the spatially structured information extracted from data with ML algorithms. Sequential simulations provide efficient assessment of uncertainty and spatial variability. Case study from the Chernobyl fallouts illustrates the performance of the proposed model. It is shown that probability mapping, provided by the combination of ML data driven and geostatistical model based approaches, can be efficiently used in decision-making process. (C) 2003 Elsevier Ltd. All rights reserved.

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Introduction. If we are to promote more patient-centred approaches in care delivery, we have to better characterize the situations in which being patient-centred is difficult to achieve. Data from professionals in health and social care are important because they are the people charged with operationalizing patient-centred care (PCC) in their daily practice. However, empirical accounts from frontline care providers are still lacking, and it is important to gather experiences not only from doctors but also from the other care providers. Indeed, experiences from different professions can help inform our understanding of patient care, which is expected to be both patient-centred and collaborative. Methods. This study was based on the following research question: What factors make the provision of PCC difficult to achieve? Sample and setting. A purposeful sampling technique was used, allowing for a series of choices about the participants and their professional affiliation. Because patient-centredness is the focus, 3 professions appeared to be of special interest: general internists, nurses and social workers. The study was undertaken in the General Internal Medicine Division of a teaching hospital located in a North American context. Data Collection. To answer the research question, a methodological approach based on a theory called phenomenology was chosen. Accordingly, semi-structured interviews were used since they generate understanding of the meanings different individuals have of their lived world. Interviews with 8 physicians, 10 nurses and 10 social workers were eventually conducted. Data analysis. An inductive thematic analysis was employed to make sense of the interview data. Results. The thematic analysis allowed identifying various types of challenges to PCC. Although most of the challenges were perceived by all three groups of professionals, they were perceived to a different degree across the professions, which likely reflected the scope of practice of each profession. The challenges and their distribution across the professions are illustrated in Table 1. Examples of challenges are provided in Table 2. Discussion. There is a tension between what is supposed to be done - what stands in the philosophy of patient -centredness - and what is currently done - the real life with all the challenges to PCC. According to some participants' accounts, PCC clearly risks becoming a mere illusion for health care professionals on which too great pressures are imposed.

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Sport betting is a lucrative business for bookmakers, for the lucky (or wise) punters, but also for governments and for sport. While not new or even recent, the deviances linked to sport betting, primarily match-fixing, have gained increased media exposure in the past decade. This exploratory study is a qualitative content analysis of the press coverage of sport betting-related deviances in football in two countries (UK and France), using in each case two leading national publications over a period of five years. Data analysis indicates a mounting coverage of sport betting scandals, with teams, players and criminals increasingly framed as culprits, while authorities and federations primarily assume a positive role. As for the origin of sport betting deviances, French newspapers tend to blame the system (in an abstract way); British newspapers, in contrast, focus more on individual weaknesses, notably greed. This article contributed to the growing body of literature on the importance of these deviances and on the way they are perceived by sport organizations, legislators and the public at large.

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Raw measurement data does not always immediately convey useful information, but applying mathematical statistical analysis tools into measurement data can improve the situation. Data analysis can offer benefits like acquiring meaningful insight from the dataset, basing critical decisions on the findings, and ruling out human bias through proper statistical treatment. In this thesis we analyze data from an industrial mineral processing plant with the aim of studying the possibility of forecasting the quality of the final product, given by one variable, with a model based on the other variables. For the study mathematical tools like Qlucore Omics Explorer (QOE) and Sparse Bayesian regression (SB) are used. Later on, linear regression is used to build a model based on a subset of variables that seem to have most significant weights in the SB model. The results obtained from QOE show that the variable representing the desired final product does not correlate with other variables. For SB and linear regression, the results show that both SB and linear regression models built on 1-day averaged data seriously underestimate the variance of true data, whereas the two models built on 1-month averaged data are reliable and able to explain a larger proportion of variability in the available data, making them suitable for prediction purposes. However, it is concluded that no single model can fit well the whole available dataset and therefore, it is proposed for future work to make piecewise non linear regression models if the same available dataset is used, or the plant to provide another dataset that should be collected in a more systematic fashion than the present data for further analysis.

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In general, laboratory activities are costly in terms of time, space, and money. As such, the ability to provide realistically simulated laboratory data that enables students to practice data analysis techniques as a complementary activity would be expected to reduce these costs while opening up very interesting possibilities. In the present work, a novel methodology is presented for design of analytical chemistry instrumental analysis exercises that can be automatically personalized for each student and the results evaluated immediately. The proposed system provides each student with a different set of experimental data generated randomly while satisfying a set of constraints, rather than using data obtained from actual laboratory work. This allows the instructor to provide students with a set of practical problems to complement their regular laboratory work along with the corresponding feedback provided by the system's automatic evaluation process. To this end, the Goodle Grading Management System (GMS), an innovative web-based educational tool for automating the collection and assessment of practical exercises for engineering and scientific courses, was developed. The proposed methodology takes full advantage of the Goodle GMS fusion code architecture. The design of a particular exercise is provided ad hoc by the instructor and requires basic Matlab knowledge. The system has been employed with satisfactory results in several university courses. To demonstrate the automatic evaluation process, three exercises are presented in detail. The first exercise involves a linear regression analysis of data and the calculation of the quality parameters of an instrumental analysis method. The second and third exercises address two different comparison tests, a comparison test of the mean and a t-paired test.

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The purpose of this two-phased study is to examine the interest of nursing students in choosing a career in older people nursing. First, the scoping phase explores the different premises for choosing older people nursing as a career. Second, the evaluation phase investigates the outcomes of the developed educational intervention involving older people as promoters of choosing a career in older people nursing, factors related to these outcomes, and experiences with educational intervention. The ultimate goal is to encourage more nursing students to choose older people nursing as their career. The scoping phase applies an exploratory design and centres around a descriptive, cross-sectional survey, documentary research and a scoping literature review. The information sources for this phase include 183 nursing students, 101 newspaper articles and 66 research articles. The evaluation phase applies a quasi-experimental design and a pre-post-test design with a non-equivalent comparison group and a post-intervention survey. The information sources for this phase include 87 nursing students and 43 older people. In both phases, statistical and narrative methods are applied in the data analysis. Nursing students neutrally regarded the idea of a career in older people nursing. The most consistent factors related to the nursing students’ career plans in older people nursing were found to be nursing work experience and various educational preparations in the field. Nursing students in the intervention group (n=40) were more interested in older people nursing and had more positive attitudes towards older people than did students in the comparison group (n=36). However, in both groups, the interest that students had at the baseline was associated with the interest at the one-month follow-up. There were no significant differences between the groups in terms of the students’ knowledge levels about ageing. The nursing students and older people alike highly appreciated participating in the educational intervention. It seems possible to positively impact nursing students and their choices to pursue careers in older people nursing, at least in the short-term. The involvement of older people as promoters of this career choice provides one encouraging alternative for impacting students’ career choices, but additional research is needed.

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Each year, the College of Nurses of Ontario (CNO) requires all registered nurses and registered practical nurses in Ontario to complete a Reflective Practice learning activity. In doing so, nurses are expected to perform a self- assessment, identify a practice problem or issue, create and implement a personal learning plan, and evaluate the learning and outcomes accomplished. The process and components of CNO's Reflective Practice program are very similar to an Action Learning activity. The purpose of this qualitative research was to explore the perceptions of 1 1 nurses who completed at least 1 Action Learning activity. Data analysis of their comments provided insight into their perceptions of the Action Learning experience, perceptions of the negative and positive characteristics of various activities within the Action Learning process, and perceptions of barriers or challenges within this experience. The author concluded that participants perceived their Action Learning activities to be a positive experience because the process focused on practice problems and issues, enhanced thinking about practice problems, and achieved practice-relevant outcomes. However, the results indicated that self-directed learning and journal writing were difficult activities for some participants, and some experienced negative emotional responses during reflection. The research concluded that barriers to implementation of Action Learning include a lack of understanding of the process and a perceived lack of support from employers.

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Triple quadrupole mass spectrometers coupled with high performance liquid chromatography are workhorses in quantitative bioanalyses. It provides substantial benefits including reproducibility, sensitivity and selectivity for trace analysis. Selected Reaction Monitoring allows targeted assay development but data sets generated contain very limited information. Data mining and analysis of non-targeted high-resolution mass spectrometry profiles of biological samples offer the opportunity to perform more exhaustive assessments, including quantitative and qualitative analysis. The objectives of this study was to test method precision and accuracy, statistically compare bupivacaine drug concentration in real study samples and verify if high resolution and accurate mass data collected in scan mode can actually permit retrospective data analysis, more specifically, extract metabolite related information. The precision and accuracy data presented using both instruments provided equivalent results. Overall, the accuracy was ranging from 106.2 to 113.2% and the precision observed was from 1.0 to 3.7%. Statistical comparisons using a linear regression between both methods reveal a coefficient of determination (R2) of 0.9996 and a slope of 1.02 demonstrating a very strong correlation between both methods. Individual sample comparison showed differences from -4.5% to 1.6% well within the accepted analytical error. Moreover, post acquisition extracted ion chromatograms at m/z 233.1648 ± 5 ppm (M-56) and m/z 305.2224 ± 5 ppm (M+16) revealed the presence of desbutyl-bupivacaine and three distinct hydroxylated bupivacaine metabolites. Post acquisition analysis allowed us to produce semiquantitative evaluations of the concentration-time profiles for bupicavaine metabolites.

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The service quality of any sector has two major aspects namely technical and functional. Technical quality can be attained by maintaining technical specification as decided by the organization. Functional quality refers to the manner which service is delivered to customer which can be assessed by the customer feed backs. A field survey was conducted based on the management tool SERVQUAL, by designing 28 constructs under 7 dimensions of service quality. Stratified sampling techniques were used to get 336 valid responses and the gap scores of expectations and perceptions are analyzed using statistical techniques to identify the weakest dimension. To assess the technical aspects of availability six months live outage data of base transceiver were collected. The statistical and exploratory techniques were used to model the network performance. The failure patterns have been modeled in competing risk models and probability distribution of service outage and restorations were parameterized. Since the availability of network is a function of the reliability and maintainability of the network elements, any service provider who wishes to keep up their service level agreements on availability should be aware of the variability of these elements and its effects on interactions. The availability variations were studied by designing a discrete time event simulation model with probabilistic input parameters. The probabilistic distribution parameters arrived from live data analysis was used to design experiments to define the availability domain of the network under consideration. The availability domain can be used as a reference for planning and implementing maintenance activities. A new metric is proposed which incorporates a consistency index along with key service parameters that can be used to compare the performance of different service providers. The developed tool can be used for reliability analysis of mobile communication systems and assumes greater significance in the wake of mobile portability facility. It is also possible to have a relative measure of the effectiveness of different service providers.

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Atmospheric surface boundary layer parameters vary anomalously in response to the occurrence of annular solar eclipse on 15th January 2010 over Cochin. It was the longest annular solar eclipse occurred over South India with high intensity. As it occurred during the noon hours, it is considered to be much more significant because of its effects in all the regions of atmosphere including ionosphere. Since the insolation is the main driving factor responsible for the anomalous changes occurred in the surface layer due to annular solar eclipse, occurred on 15th January 2010, that played very important role in understanding dynamics of the atmosphere during the eclipse period because of its coincidence with the noon time. The Sonic anemometer is able to give data of zonal, meridional and vertical wind as well as the air temperature at a temporal resolution of 1 s. Different surface boundary layer parameters and turbulent fluxes were computed by the application of eddy correlation technique using the high resolution station data. The surface boundary layer parameters that are computed using the sonic anemometer data during the period are momentum flux, sensible heat flux, turbulent kinetic energy, frictional velocity (u*), variance of temperature, variances of u, v and w wind. In order to compare the results, a control run has been done using the data of previous day as well as next day. It is noted that over the specified time period of annular solar eclipse, all the above stated surface boundary layer parameters vary anomalously when compared with the control run. From the observations we could note that momentum flux was 0.1 Nm 2 instead of the mean value 0.2 Nm-2 when there was eclipse. Sensible heat flux anomalously decreases to 50 Nm 2 instead of the mean value 200 Nm 2 at the time of solar eclipse. The turbulent kinetic energy decreases to 0.2 m2s 2 from the mean value 1 m2s 2. The frictional velocity value decreases to 0.05 ms 1 instead of the mean value 0.2 ms 1. The present study aimed at understanding the dynamics of surface layer in response to the annular solar eclipse over a tropical coastal station, occurred during the noon hours. Key words: annular solar eclipse, surface boundary layer, sonic anemometer

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Modern methods of compositional data analysis are not well known in biomedical research. Moreover, there appear to be few mathematical and statistical researchers working on compositional biomedical problems. Like the earth and environmental sciences, biomedicine has many problems in which the relevant scienti c information is encoded in the relative abundance of key species or categories. I introduce three problems in cancer research in which analysis of compositions plays an important role. The problems involve 1) the classi cation of serum proteomic pro les for early detection of lung cancer, 2) inference of the relative amounts of di erent tissue types in a diagnostic tumor biopsy, and 3) the subcellular localization of the BRCA1 protein, and it's role in breast cancer patient prognosis. For each of these problems I outline a partial solution. However, none of these problems is \solved". I attempt to identify areas in which additional statistical development is needed with the hope of encouraging more compositional data analysts to become involved in biomedical research

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Hydrogeological research usually includes some statistical studies devised to elucidate mean background state, characterise relationships among different hydrochemical parameters, and show the influence of human activities. These goals are achieved either by means of a statistical approach or by mixing models between end-members. Compositional data analysis has proved to be effective with the first approach, but there is no commonly accepted solution to the end-member problem in a compositional framework. We present here a possible solution based on factor analysis of compositions illustrated with a case study. We find two factors on the compositional bi-plot fitting two non-centered orthogonal axes to the most representative variables. Each one of these axes defines a subcomposition, grouping those variables that lay nearest to it. With each subcomposition a log-contrast is computed and rewritten as an equilibrium equation. These two factors can be interpreted as the isometric log-ratio coordinates (ilr) of three hidden components, that can be plotted in a ternary diagram. These hidden components might be interpreted as end-members. We have analysed 14 molarities in 31 sampling stations all along the Llobregat River and its tributaries, with a monthly measure during two years. We have obtained a bi-plot with a 57% of explained total variance, from which we have extracted two factors: factor G, reflecting geological background enhanced by potash mining; and factor A, essentially controlled by urban and/or farming wastewater. Graphical representation of these two factors allows us to identify three extreme samples, corresponding to pristine waters, potash mining influence and urban sewage influence. To confirm this, we have available analysis of diffused and widespread point sources identified in the area: springs, potash mining lixiviates, sewage, and fertilisers. Each one of these sources shows a clear link with one of the extreme samples, except fertilisers due to the heterogeneity of their composition. This approach is a useful tool to distinguish end-members, and characterise them, an issue generally difficult to solve. It is worth note that the end-member composition cannot be fully estimated but only characterised through log-ratio relationships among components. Moreover, the influence of each endmember in a given sample must be evaluated in relative terms of the other samples. These limitations are intrinsic to the relative nature of compositional data

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The statistical analysis of compositional data should be treated using logratios of parts, which are difficult to use correctly in standard statistical packages. For this reason a freeware package, named CoDaPack was created. This software implements most of the basic statistical methods suitable for compositional data. In this paper we describe the new version of the package that now is called CoDaPack3D. It is developed in Visual Basic for applications (associated with Excel©), Visual Basic and Open GL, and it is oriented towards users with a minimum knowledge of computers with the aim at being simple and easy to use. This new version includes new graphical output in 2D and 3D. These outputs could be zoomed and, in 3D, rotated. Also a customization menu is included and outputs could be saved in jpeg format. Also this new version includes an interactive help and all dialog windows have been improved in order to facilitate its use. To use CoDaPack one has to access Excel© and introduce the data in a standard spreadsheet. These should be organized as a matrix where Excel© rows correspond to the observations and columns to the parts. The user executes macros that return numerical or graphical results. There are two kinds of numerical results: new variables and descriptive statistics, and both appear on the same sheet. Graphical output appears in independent windows. In the present version there are 8 menus, with a total of 38 submenus which, after some dialogue, directly call the corresponding macro. The dialogues ask the user to input variables and further parameters needed, as well as where to put these results. The web site http://ima.udg.es/CoDaPack contains this freeware package and only Microsoft Excel© under Microsoft Windows© is required to run the software. Kew words: Compositional data Analysis, Software

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The aim of this talk is to convince the reader that there are a lot of interesting statistical problems in presentday life science data analysis which seem ultimately connected with compositional statistics. Key words: SAGE, cDNA microarrays, (1D-)NMR, virus quasispecies

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A presentation on the collection and analysis of data taken from SOES 6018. This module aims to ensure that MSc Oceanography, MSc Marine Science, Policy & Law and MSc Marine Resource Management students are equipped with the skills they need to function as professional marine scientists, in addition to / in conjuction with the skills training in other MSc modules. The module covers training in fieldwork techniques, communication & research skills, IT & data analysis and professional development.