916 resultados para Partial least square regression
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Purpose: To develop an effective method for evaluating the quality of Cortex berberidis from different geographical origins. Methods: A simple, precise and accurate high performance liquid chromatography (HPLC) method was first developed for simultaneous quantification of four active alkaloids (magnoflorine, jatrorrhizine, palmatine, and berberine) in Cortex berberidis obtained from Qinghai, Tibet and Sichuan Provinces of China. Method validation was performed in terms of precision, repeatability, stability, accuracy, and linearity. Besides, partial least squares discriminant analysis (PLS-DA) and one-way analysis of variance (ANOVA) were applied to study the quality variations of Cortex berberidis from various geographical origins. Results: The proposed HPLC method showed good linearity, precision, repeatability, and accuracy. The four alkaloids were detected in all samples of Cortex berberidis. Among them, magnoflorine (36.46 - 87.30 mg/g) consistently showed the highest amounts in all the samples, followed by berberine (16.00 - 37.50 mg/g). The content varied in the range of 0.66 - 4.57 mg/g for palmatine and 1.53 - 16.26 mg/g for jatrorrhizine, respectively. The total content of the four alkaloids ranged from 67.62 to 114.79 mg/g. Moreover, the results obtained by the PLS-DA and ANOVA showed that magnoflorine level and the total content of these four alkaloids in Qinghai and Tibet samples were significantly higher (p < 0.01) than those in Sichuan samples. Conclusion: Quantification of multi-ingredients by HPLC combined with statistical methods provide an effective approach for achieving origin discrimination and quality evaluation of Cortex berberidis. The quality of Cortex berberidis closely correlates to the geographical origin of the samples, with Cortex berberidis samples from Qinghai and Tibet exhibiting superior qualities to those from Sichuan.
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Tese (doutorado)–Universidade de Brasília, Instituto de Química, Programa de Pós-Graduação em Química, 2016.
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The purpose of this research was to examine the relationship between teaching readiness and teaching excellence with three variables of preparedness of adjunct professors teaching career technical education courses through student surveys using a correlational design of two statistical techniques; least-squares regression and one-way analysis of variance. That is, the research tested the relationship between teacher readiness and teacher excellence with the number of years teaching, the number of years of experience in the professional field and exposure to teaching related professional development, referred to as variables of preparedness. The results of the research provided insight to the relationship between the variables of preparedness and student assessment of their adjunct professors. Concerning the years of teaching experience, this research found a negative inverse relationship with how students rated their professors’ teaching readiness and excellence. The research also found no relationship between years of professional experience and the students’ assessment. Lastly, the research found a significant positive relationship between the amount of teaching related professional development taken by an adjunct professor and the students’ assessment in teaching readiness and excellence. This research suggests that policies and practices at colleges should address the professional development needs of adjunct professors. Also, to design a model that meets the practices of inclusion for adjunct faculty and to make professional development a priority within the organization. Lastly, implement that model over time to prepare adjuncts in readiness and excellence.
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A substantial amount of work in the field of strategic management has attempted to explain the antecedents and outcomes of organizational learning. Though multinational corporations simultaneously engage in various types of tasks, activities, and strategies on a regular basis, the transfer of organizational learning in a multi-task context has largely remained under-explored in the literature. To inform our understanding in this area, this dissertation aimed at synthesizing findings from two parallel research streams of corporate development activities: strategic alliances and acquisitions. Structured in the form of two empirical studies, this dissertation examines: 1) the strategic outcomes of alliance experience of previously allying partners in terms of subsequent acquisition attempts, and 2) the performance implications of prior alliance experience for acquisitions. The first study draws on the relational view of inter-organizational governance to explain how various deal-specific and dyadic characteristics of a partnership relate to partnering firms’ post-alliance acquisition attempts. This model theorizes on a variety of relational mechanisms to build a cohesive theory of inter-organizational exchanges in a multi-task setting where strategic alliances ultimately lead to a firm’s decision to commit further resources. The second study applies organizational learning theory, and specifically examines whether frequency, recency, and relatedness of different dimensions of prior alliances, beyond the dyad-level experience, relate to an acquirer’s superior post-acquisition performance. The hypotheses of the studies are tested using logistic and ordinary least square regressions, respectively. Results analyzed from a sample of cross-border alliance and acquisition deals attempted (for study I) and/or completed (for study II) during the period of 1991 to 2011 generally support the theory that relational exchange determines acquiring firms’ post alliance acquisition behavior and that organizational routines and learning from prior alliances influence a future acquirer’s financial performance. Overall, the empirical findings support our overarching theory of interdependency, and confirm the transfer effect of learning across these alternate, yet related corporate strategies of alliance and acquisition.
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Purpose – The purpose of this empirical paper is to investigate internal marketing from a behavioural perspective. The impact of internal marketing behaviours, operationalised as an internal market orientation (IMO), on employees' marketing and other in/role behaviours (IRB) were examined. Design/methodology/approach – Survey data measuring IMO, market orientation and a range of constructs relevant to the nomological network in which they are embedded were collected from the UK retail managers. These were tested to establish their psychometric properties and the conceptual model was analysed using structural equations modelling, employing a partial least squares methodology. Findings – IMO has positive consequences for employees' market/oriented and other IRB. These, in turn, influence marketing success. Research limitations/implications – The paper provides empirical support for the long/held assumption that internal and external marketing are related and that organisations should balance their external focus with some attention to employees. Future research could measure the attitudes and behaviours of managers, employees and customers directly and explore the relationships between them. Practical implications – Firm must ensure that they do not put the needs of their employees second to those of managers and shareholders; managers must develop their listening skills and organisations must become more responsive to the needs of their employees. Originality/value – The paper contributes to the scarce body of empirical support for the role of internal marketing in services organisations. For researchers, this paper legitimises the study of internal marketing as a route to external market success; for managers, the study provides quantifiable evidence that focusing on employees' wants and needs impacts their behaviours towards the market. © 2010, Emerald Group Publishing Limited
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Brands are those lifestyles which consumers chose to buy in order to gain the value offered by the company, in order to be part of the community created through the brand equity elements and validated in the purchase of the products. Companies have understood how important it is to build a strong brand and many of them spend millions on aligning the brand with the design and style of the products, projecting the face and values of the company into the advertising campaigns. One of the most popular methods is through endorsement, placing a renounced celebrity and leveraging on the positive feedback of those customers that also follow the activities of the star whose face is on the cover of the marcom campaign. Celebrities have been used for a very long time to promote brands, sell products and services. Research has shown that those spokesmen of a brand who are more attractive can improve the statistics of recall and appeal more interest to the promotion campaign, as well as influence more on customer’s intention of buying the product (Kahle and Homer, 1985). The main purpose of this research is to investigate how celebrity endorsements influence the brand equity dimensions (brand loyalty, brand awareness, perceived quality and brand associations) as well as stimulate consumers’ word-of-mouth through brand identification, growth in interest and the advertising memorability. The hypotheses were tested with the aid of Structural Equation Modelling (SEM) in the PLS (Partial Least Squares) software. The survey is comprised of a target group of 589 respondents, from three countries – Brazil, Moldova and Portugal. Results evidence that the Attitude towards the Celebrity influences different Brand Equity dimensions and affects brand identification, growth in advertisement interest and advertising memorability, generating positive word of mouth (or negative, depending on the type of advertisement and reputation). Based on these findings we suggest further investigation in this area with the possibility to gain more data about the different fields of marcom and the different types of CE which are more appropriate for the given type of business.
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This study aims to determine which factors influence travellers’ intentions to purchase travel online by proposing and empirically testing a new model grounded on the theory of planned behaviour. In order to validate the model, a web-based questionnaire was applied and a total of 1732 valid responses were obtained. The findings show that attitudes, perceived risk, and perceived behavioural control have significant effects on intentions to purchase travel online. However, contrary to what was expected, neither trust nor the influence of others seems to directly affect intentions to purchase travel online. Finally, the paper discusses the findings with the implicationsfor theory and practice and makes several suggestions for future research.
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This study aims to determine which factors influence travellers’ intentions to purchase travel online by proposing and empirically testing a new model grounded on the theory of planned behaviour. In order to validate the model, a web-based questionnaire was applied and a total of 1732 valid responses were obtained. The findings show that attitudes, perceived risk, and perceived behavioural control have significant effects on intentions to purchase travel online. However, contrary to what was expected, neither trust nor the influence of others seems to directly affect intentions to purchase travel online. Finally, the paper discusses the findings with the implications for theory and practice and makes several suggestions for future research.
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Esta investigación de carácter exploratorio, contribuye a explicar cómo afecta al comportamiento innovador de la pyme manufacturera dos filosofías empresariales. En concreto, se estudia el impacto sobre el comportamiento innovador del compromiso por la calidad y del fomento de una cultura emprendedora, bajo un enfoque de dirección participativa. Para ello se establece un modelo estructural con las relaciones entre dichas variables y se analiza con la técnica PLS (Partial Least Squares). Los resultados muestran que tanto una como otra postura afectan al comportamiento innovador de una manera muy similar.
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Tesis inédita presentada en la Universidad Europea de Madrid. Facultad de Ciencias Sociales. Programa de Doctorado en Economía y Empresa
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Solar radiation data is crucial for the design of energy systems based on the solar resource. Since diffuse radiation measurements are not always available in the archive data series, either due to the inexistence of measuring equipment, shading device misplacement or missing data, models to generate these data are needed. In this work, one year of hourly and daily horizontal solar global and diffuse irradiation measurements in Évora are used to establish a new relation between the diffuse radiation and the clearness index. The proposed model includes a fitting parameter, which was adjusted through a simple optimization procedure to minimize the Least Square Error as compared to measurements. A comparison against several other fitting models presented in the literature was also carried out using the Root Mean Square Error as statistical indicator, and it was found that the present model is more accurate than the previous fitting models for the diffuse radiation data in Évora.
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Il lavoro di questa tesi è stato implementare su Matlab un algoritmo numerico che permettesse di determinare la posizione di un utilizzatore mediante misure GPS. In particolare, dopo un'introduzione al sistema GPS e alla navigazione GPS, è stato analizzato il contenuto dei LOG di ESEO e si è proceduto all'implementazione dell'algoritmo sul calcolatore. Lo scopo ultimo della tesi è stato verificare l'accuratezza di tale algoritmo, mediante il calcolo degli errori con le posizioni reali e mediante una verifica tramite calcolo del range geometrico.
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This research presents a method for frequency estimation in power systems using an adaptive filter based on the Least Mean Square Algorithm (LMS). In order to analyze a power system, three-phase voltages were converted into a complex signal applying the alpha beta-transform and the results were used in an adaptive filtering algorithm. Although the use of the complex LMS algorithm is described in the literature, this paper deals with some practical aspects of the algorithm implementation. In order to reduce computing time, a coefficient generator was implemented. For the algorithm validation, a computing simulation of a power system was carried Out using the ATP software. Many different situations were Simulated for the performance analysis of the proposed methodology. The results were compared to a commercial relay for validation, showing the advantages of the new method. (C) 2009 Elsevier Ltd. All rights reserved.
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Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.