A control chart that simultaneously tracks the mean and variance of a normally distributed variable with no compensation effect is defined in this work. This joint control chart is compared to five other charts: an Χ chart, an s² chart, a Reynolds and Ghosh chart, a Repko process capability plot, and a t-statistic chart. The criterion for comparison is the probability of a Type II sampling error. Several out-of-control cases are examined. In the case of Repko, an equation is defined to compute the Type II error probability. The results indicate that the Reynolds and Ghosh statistic is powerful for cases when the variance shifts out of control. The Χ chart is powerful when the mean shifts with moderate changes in the variance. The joint chart is powerful for moderate changes in the mean and variance. / Master of Science

Yes / The growth of cocrystalline phases continues to expand as a key area of crystal engineering research. Understanding the phase behavior of the material and controlling the crystalline form of the material from a solution-based route can be aided by the construction of a ternary phase diagram for the system. A range of methods exist for this process which display a variety of costs and time to achieve the final diagram. The application of quantitative NMR (qNMR) to this problem offers a fast analysis method to directly determine the solution composition of all species (coformers and solvent) and is demonstrated to successfully allow the construction of ternary diagrams with and without a cocrystal phase being formed for systems with high and low solubility.

Most control charts monitor only one quality characteristic. There are, however, many manufactured products for which good quality requires meeting specifications in more than one physical characteristic. Typical practice when dealing with multiple quality characteristics is to take a separate sample for each characteristic and then create individual univariate control charts which are independently monitored. This method can result in errors due to not accounting for the effects of correlation. In order to avoid these errors, an alternate approach to multivariate quality control problems is proposed and studied here. The original problem is converted into a univariate problem by using the following transformation: y=Σ a_ix_i i where αi = weighting coefficient for the i^th quality characteristic X_i = represents the i^th quality characteristic This transformation retains sensitivity to changes in the original quality variables. The resulting univariate quality control model takes into account the sampling error probabilities for each of several candidate hypotheses. The probabilities of correctly diagnosing process shifts when an out-of-control state occurs are calculated and tabulated as are the probabilities that the model will signal when an out-of-control state occurs. / Master of Science

Yes / This paper introduces a novel method referred to as Enhanced Sequence Diagram (ESD) to support rigorous functional modelling of complex multidisciplinary systems. The ESD concept integrates an exchanges based functional requirements reasoning based on a coherent graphical schema, integrated with the system operational analysis based on a sequence diagram. The effectiveness of the method to support generic function modelling of complex multidisciplinary systems at the early conceptual design stages is discussed in conjunction with an electric vehicle powertrain example, followed by an assessment of potential impact for broader application of the method in the industry.

In recent years, variable sampling interval (VSI) control charts have been intensively investigated. In contrast to traditional fixed sampling interval (FSI) control charts, VSI charts vary the sampling interval as a function of the data. VSI charts detect many process changes faster than their FSI counterparts. A disadvantage, however, of VSI charts as recently formulated is that the advance prediction of sampling times is impossible for more than the next sample. A control chart is proposed which applies a sequential probability ratio test (SPRT) at fixed sampling intervals, the SPRT chart, to monitor the mean of a process with a normal distribution. A natural modification of the SPRT chart, the SPRT chart with sampling at fired times (SFT), is also proposed in which samples are always taken at pre-specified, equally spaced fixed times, with additional samples taken between these times as indicated by the data. A third control chart is introduced as a generalization of the VSI cumulative sum (CUSUM) chart that uses two sampling intervals, called the universal CUSUM (UC) chart, in order to address the need for a general framework for the study of control charts that are equivalent to a sequence of SPRT’s. The UC chart can also be viewed as a generalization of the SPRT chart. The integral equation approach is adapted for the evaluation of properties of both the unmodified and modified with SFT versions of the SPRT chart, such as average time to signal (ATS), steady state ATS (SSATS), and average number of observations to signal (ANOS). After comparisons are performed within the general framework of the UC chart, the unmodified SPRT chart is found to be more efficient than both the FSI and VSI X charts and the FSI CUSUM chart, though very similar in efficiency to the VSI CUSUM chart. The modified SPRT chart with SFT is found to be more efficient than all five of the other control charts, including its unmodified version and the VSI CUSUM chart. General guidelines are provided for the design of both versions of the SPRT chart. / Ph. D.

The thermodynamic and kinetic phenomena involved in the formation of sub-micron polyimide particles from polyimide/solvent/nonsolvent ternary systems were studied. A quantitative equilibrium approach was considered in the B-bonding studies of these ternary systems. The effect of H-bonding on the physical properties and phase behavior of the ternary systems was investigated. The critical requirements for the control of polymer particle size and size distribution during particle formation by precipitation from solution are discussed. It was found that the equilibrium constants, enthalpies and entropies of H-bonding in the ternary systems containing water can be obtained by analysis of the ^lH_NMR data. Using the calculated equilibrium constants, the determination of the concentration of H-bonds between N-methylpyrrolidinone (NHP) and water is possible. We found a very good correlation between the B-bond concentrations and the deviations of the specific volume and viscosity from ideal mixing in the NHP/water mixtures. / Ph. D.

The standard Shewhart control chart for monitoring process stability is generalized by selecting a point in time at which the distance between the control limits is reduced. Three cost models are developed to describe the total cost per unit time of monitoring the mean of a process using both the standard and the generalized Shewhart control chart. The cost models are developed under the assumption that the quality characteristic of interest is normally distributed with known and constant variance. In the development of the first model, the negative exponential distribution is employed to model the time to process shift. Then, the uniform distribution and the Weibull distribution are used for the same purpose in the second and the third model, respectively. The motivation for this effort is to increase chart sensitivity to small but anticipated shifts in the process average. Cost models are constructed to allow the optimal choice of change over time and the best values for the initial and adjusted control limit values. The cost models are analyzed to determine the optimal control chart parameters including those associated with both the standard and the generalized control chart. The models are also used to provide a comparison with conventional implementation of the control chart. It is shown that the proposed cost models are efficient and economical. Figures and tables are provided to aid in the design of models for both the standard and the generalized Shewhart control chart. / Ph. D.

Control charts based on cumulative gauging scores rely on gauge scoring systems used for transforming actual observations into integer gauging scores. In some cases, the gauging scores are easy to obtain by using a mechanical device such as in the go-no-go inspection process. Thus, accurate measurements of selected quality characteristics are not necessary. Also, different control purposes can be achieved p by using different scoring systems. Cumulative gauging score charts based on two pairs of gauges are proposed to control the process mean or the standard deviation by either gauging one or several observations. Both random walk and cusum type cumulative gauging score charts are used. For controlling the process mean and standard deviation at the same time, a cusum type and a two-dimensional random walk type procedure are proposed. A gauging scheme can be applied to multivariate quality control by gauging either x² or T² statistics. A simple multivariate control chart which is based on the multivariate sign score vector is also proposed. The exact run length distribution of these cumulative gauging score charts can be obtained by formulating the procedures as Markov chain processes. For some procedures, the average run length (ARL) can be obtained in a closed form expression by solving a system of difference equations with appropriate boundary conditions. Comparisons based on the ARL show that the cumulative gauging score charts can detect small shifts in the quality characteristic more quickly than the Shewhart type X-chart. The efficiency of the cusum type gauging score chart is close to the regular CUSUM chart. The random walk type gauging score chart is more robust than the Shewhart and CUSUM charts to observations which have heavy a tailed distribution or which are serially correlated. For multivariate quality control. A procedure based on gauging the x² statistic has better performance than the x² chart. Also, a new multivariate control chart procedure which is more robust to the misspecification of the correlation than the x² chart is proposed. / Ph. D.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2017-09-14T18:41:16Z No. of bitstreams: 1 dissertacao_saulo_toledo_recsys_uml.pdf: 2345909 bytes, checksum: dcaa7238380f7791f922778432a5b9ea (MD5) / Made available in DSpace on 2017-09-14T18:41:16Z (GMT). No. of bitstreams: 1 dissertacao_saulo_toledo_recsys_uml.pdf: 2345909 bytes, checksum: dcaa7238380f7791f922778432a5b9ea (MD5) Previous issue date: 2016-09-05 / Modelos UML são usados de várias formas na engenharia de software. Eles podem modelar desde requisitos até todo o software, e compreendem vários diagramas. O diagrama de classes, o mais popular dentre os diagramas da UML, faz uso de vários elementos UML e adornos, tais como abstração, interfaces, atributos derivados, conjuntos de generalização, composições e agregações. Atualmente, não há maneira fácil de encontrar este tipo de diagrama com base nestas características para a reutilização ou a aprendizagem por tarefas de exemplo. Por outro lado, Sistemas de Recomendação são ferramentas e técnicas que são capazes de descobrir os elementos mais adequados para um usuário, dentre muitos outros. Existem várias técnicas de recomendação, que usam informações dos elementos de várias maneiras, ao uso da opinião de outros usuários. Sistemas de recomendação já foram utilizados com sucesso em vários problemas de engenharia de software. Este trabalho tem como objetivo propor e avaliar (i) uma representação baseada em conteúdo para diagramas de classe e as preferências do usuário,(ii) um novo algoritmo de recomendação baseado no conhecimento, (iii) a aplicação deste algoritmo e outros dois outros do estado da arte para a recomendação de diagramas de classe UML e (iv) uma avaliação destas abordagens contra uma sugestão aleatória. Para atingir este objetivo, foi realizado um estudo de caso com estudantes de ciência da computação e egressos. Depois de comparar os algoritmos, os nossos resultados mostram que, para o nosso conjunto de dados, todos eles são melhores do que uma recomendação aleatória. / UML models are used in several ways in the software engineering. They can model from requirements to the entire software, and comprise several diagrams. The Class diagram, the most popular among the UML diagrams, makes use of several UML elements and adornments, such as abstraction, interfaces, derived attributes, generalization sets, compositions and aggregations. Currently, there is no easy way to find this kind of diagram based on these features for reuse or learning by example’s tasks, for instance. On the other hand, Recommender Systems are powerful tools and techniques that are able to discover the most appropriate elements to an user among many others. There are several recommender techniques, from using the elements’ information in several ways, to using other users’ opinions. Recommender systems were already used successfully in several software engineering problems, as discovering pieces of code to recommend (as methods, for example) and finding the best developer to work in certain software problems. This work aims to propose and evaluate (i) a content-based Recommender System’s representation for class diagrams’ features and user’s preferences, (ii) a new knowledge-based recommender algorithm, (iii) the application this algorithm and two other state of the art content-based ones to the recommendation of UML class diagrams and (iv) an evaluation of these approaches against a random suggestion. To achieve this goal, we conducted a case study with computer science students and egresses. After comparing the algorithms, our results show that, for our dataset, all of them are better than a random recommendation.

The subject of the master thesis Process driven organization is using UML language and BPMN methodology to model business processes of the selected organization, followed by using obtained diagrams organization for upgrade any of modeled diagram existing business processes leading to prosperity of the selected organization.