Syftet med arbetet är att belysa och förbättra maskinunderhållet inom Sweprod. Detta med fokus på eloxeringsprocessen samt att identifiera hur förebyggande underhåll på bästa sätt kan införas på Sweprod. Målet med studien är att ge organisationen en bild av hur det förebyggande underhållet ser ut och att ge dem förslag på vad det finns för förbättringsåtgärder och hur det kan implementeras. Organisationen har, som många andra verksamheter som arbetar inom tillverkning av produkter, många maskiner som kräver någon typ av underhåll. Ytbehandlingsprocessen som studien beskriver, kallas för eloxering och är en process som hanterar ytan på plåtar för att kunna färglägga dempå ett korrekt sätt. Oplanerade driftstopp på maskiner och förseningar i leveranser av produkter inom organisationen har gjort att underhållsprocessen hamnat i fokus. Organisationen reagerar oftare när något händer i form av korrigerande underhåll istället för att planera in förebyggande underhåll eller villkorbaserat underhåll för att minska sannolikheten att något händer. Det har gjort att organisationen vill se över rutinerna kring underhållet med fokus på det förebyggande underhållet. Studien lyfter främst fram olika underhållsstrukturer med inriktning på förebyggande underhåll. Studien hanterar även förslag på hur organisationer på ett effektivt sätt kan arbeta med att implementera eventuella förbättringsområden som identifieras med hjälp av kvalitetsverktyg. Intervjuer med medarbetare och ledning inom organisationen har varit en stor faktor för att identifiera orsaker till att underhållet anses vara bristfälligt. Det har resulterat i att identifiering av grundorsaker inom eloxeringsprocessen har hittats som visar att med relation till olika underhållsstrukturer finns förbättringsmöjligheter inom främst helhetsstrukturen. Det som ligger i fokus är främst underliggande struktur i from av Maintenance Management, Routine Maintenance Program, Reliability-Centered Maintenance, Total Productive Maintenance. Inom eloxeringsprocessen finns det också flera kontrollmätningar som inte används till det förebyggande underhållet. Hade processen strukturerats med hjälp av Maintenance Management hade ett villkorbaserat underhåll varit av nytta för processen. Studien som har utförts av författaren har stegvis gett en inblick i vilka orsaker som är bristfälliga inom organisationen. Det har också gett en mer detaljerad inblick i eloxeringsprocessen, där det även identifierades grundorsaker som visar att underhållsstrukturen är en faktor till att förebyggande underhållet anses vara bristfälligt. Studien har också med hjälp av tidigare forskning identifierat angreppsätt för hur strukturen bör se ut inom organisationen med koppling till undersökningen som gjorts. Förslag har också presenterats på hur organisationen på ett effektivt sätt skulle kunna implementera underhållsstrukturen till eloxeringsprocessen med hjälp av en implementeringsprocess.

En el Perú, la industria alimentaria es una de las principales industrias que aportan al sector manufacturero y a la economía nacional. En el 2019, generó ventas de hasta US$ 9 mil millones, según datos de América Economía. Sin embargo, las empresas peruanas se ven enfrentadas a grandes deficiencias, provocando esto brechas competitivas respecto a otros países Latinoamericanos, siendo los productos defectuosos la principal problemática que se presenta sobre todo en las pymes. Dicha problemática no solo afecta en la calidad de los productos sino también en la rentabilidad del negocio, perjudicando la competitividad en medio de un mercado cambiante y cada vez más demandante de un mejor servicio. El presente trabajo de investigación busca analizar la situación actual de trabajo en una pyme de la industria alimentaria y proponer herramientas de mejora en los procesos con el fin de incrementar su competitividad y satisfacer a sus clientes con los más altos estándares de calidad. Como parte de esta investigación se proporcionarán los principales estudios y modelos más destacados basados en la filosofía Lean que permitirán plantear diferentes alternativas de solución para la problemática identificada en la empresa en estudio. Estas alternativas buscan mejorar la calidad de los productos y además conseguir una cultura de mejora continua. Por último, esta investigación tiene como objetivo establecer las herramientas más adecuadas de la filosofía Lean para la solución de las causas raíz identificadas en el diagnóstico, además de implementar las propuestas de mejora necesarias en la organización, a fin de optimizar los procesos productivos. De esta manera, se conseguirá obtener procesos estandarizados y eficientes, modificando métodos de trabajo e incrementando la eficiencia de los equipos para aumentar los niveles de calidad. / In Peru, the food industry is one of the main industries that contribute to the manufacturing sector and to the national economy. In 2019, it generated sales of up to US$ 9 billion, according to data from América Economía. However, Peruvian companies are faced with major deficiencies, causing these competitive gaps with respect to other Latin American countries, being defective products the main problem that occurs especially in SMEs. This problem not only affects the quality of the products but also the profitability of the business, harming competitiveness in the midst of a changing market and increasingly demanding of a better service. This research work seeks to analyse the current work situation in an SME in the food industry and propose tools to improve processes in order to increase its competitiveness and satisfy its customers with the highest quality standards. As part of this research, will be provided the main studies and most outstanding models based on Lean philosophy, that will allow to propose different solution alternatives for the problem identified in the company under study. These alternatives seek to improve the quality of the products and also achieve a culture of continuous improvement. Finally, this research aims to establish the most appropriate tools of the Lean philosophy for the solution of the root causes identified in the diagnosis, in addition to implementing the necessary improvement proposals in the organization, in order to optimize production processes. In this way, it will be possible to obtain standardized and efficient processes, modifying work methods and increasing the efficiency of the equipment to increase quality levels. / Trabajo de Suficiencia Profesional

Os recentes avanços na manufatura inteligente abrem oportunidades na área do suporte industrial, especificamente na manutenção e gestão de ativos físicos. Essa tendência permite que os dados coletados das máquinas, quando estão em pleno funcionamento, possam interagir com computadores, (ciberespaço), através de uma rede de comunicação formando assim o conceito de Sistemas Ciberfísicos (CPS – do inglês Cyber-Physical Systems). Além disso, os rápidos avanços da tecnologia de informação e comunicação proporcionam ferramentas para que essa interação possa analisar os dados, de forma cada vez mais rápida, autônoma, ubíqua e em tempo real, oferecendo informações que auxiliam aos humanos na tomada de decisões mais eficazes. Nesse contexto, o Prognóstico e Gestão da Saúde de máquinas (PHM – do inglês Prognostics Health and Management) é indicado como uma aplicação promissora da manufatura inteligente dentro do contexto de CPS. Atualmente as propostas de PHM encontradas na literatura cientifica são aplicadas a casos específicos e sem uma padronização da sua implementação, impedindo que tais abordagens possam ser replicadas em diferentes cenários da manufatura. Assim, o presente trabalho propõe a construção de um modelo ontológico para auxiliar na implementação do PHM em diversos cenários de manufatura, a ser aproveitada futuramente por ferramentas de softwares com foco em manufatura inteligente, padronizando seus conceitos, termos, e a forma de coleta e tratamento de dados. A abordagem metodológica DSR (do inglês Design Science Research) é usada para guiar o desenvolvimento da pesquisa. A construção deste modelo ontológico, que integra tanto os dados coletados quanto as informações necessárias para a tomada de decisões, possibilita o controle da estimativa de uma falha antes dela ocorrer de uma forma mais autônoma. Os principais resultados do modelo ontológico construído são: uma ontologia flexível capaz de ser usada em vários tipos de máquinas mecânicas de diversos tipos de manufatura; a possibilidade de armazenar o conhecimento contido em normas internacionais, históricos de atividades das máquinas, e arquiteturas consolidadas no contexto do PHM, permitindo a constante atualização de dados dependendo de particularidades que cada processo produtivo pode conter, e finalmente, usando a linguagem SPARQL entrega-se informações que podem ser usadas para tomada de decisões em intervenções oportunas de manutenção nos equipamentos de uma indústria real. O modelo é demonstrado considerando o caso de uma bomba centrífuga que comprovou sua fidelidade, integridade, nível de detalhe, robustez e consistência, fornecendo informações anteriormente alimentadas por dados reais obtidos em empresas próximas. / Recent advances in smart manufacturing open up opportunities in industrial support, specifically in maintenance and physical asset management. This trend allows data collected from machines, when are in full operation, to interact with cyberspace computers through a communication network, thus forming the concept of cyber-physical systems (CPS). Besides, rapid advances in information and communications technologies provide tools for analysing data, in an increasingly rapid, autonomously, ubiquitous and in real time way, providing information that assists humans in making better decisions. In this sense, Prognostics and Health Management (PHM) of machines, is indicated as a promising application of Smart Manufacturing in the CPS contexto. Currently the PHM proposals found in the scientific literature are applied to specific cases and without a standardization of their implementation, preventing such approaches from being replicated in different manufacturing scenarios. Thus, the present work proposes the construction of an ontological model to assist in the implementation of the PHM in several manufacturing scenarios, to be harnessed in the future by software tools focused on intelligent manufacturing, standardizing their concepts, terms, and the form of data collection and processing. The DSR (Design Science Research) methodological approach is used to guide the development of the research. The construction of this ontological model, which integrates both the collected data and the necessary information for the decision making, allows the control of the estimate of a failure before it occurs in a more autonomous way. The main results of the ontological model are: a flexible ontology capable of being used on several types of mechanical machines of various types of manufacturing; the possibility of storing the knowledge contained in international standards, machine history of activities, and consolidated architectures in the context of the PHM, allows the constant updating of data depending on particularities that each productive process can contain, and finally, using the SPARQL language, it is given information that can be used for decisionmaking in timely maintenance interventions in the equipment of a real industry. The model is demonstrated considering the case of a centrifugal pump that proved its fidelity, integrity, level of detail, robustness and consistency, providing information previously fed by real data obtained in nearby companies.

Os recentes avanços na manufatura inteligente abrem oportunidades na área do suporte industrial, especificamente na manutenção e gestão de ativos físicos. Essa tendência permite que os dados coletados das máquinas, quando estão em pleno funcionamento, possam interagir com computadores, (ciberespaço), através de uma rede de comunicação formando assim o conceito de Sistemas Ciberfísicos (CPS – do inglês Cyber-Physical Systems). Além disso, os rápidos avanços da tecnologia de informação e comunicação proporcionam ferramentas para que essa interação possa analisar os dados, de forma cada vez mais rápida, autônoma, ubíqua e em tempo real, oferecendo informações que auxiliam aos humanos na tomada de decisões mais eficazes. Nesse contexto, o Prognóstico e Gestão da Saúde de máquinas (PHM – do inglês Prognostics Health and Management) é indicado como uma aplicação promissora da manufatura inteligente dentro do contexto de CPS. Atualmente as propostas de PHM encontradas na literatura cientifica são aplicadas a casos específicos e sem uma padronização da sua implementação, impedindo que tais abordagens possam ser replicadas em diferentes cenários da manufatura. Assim, o presente trabalho propõe a construção de um modelo ontológico para auxiliar na implementação do PHM em diversos cenários de manufatura, a ser aproveitada futuramente por ferramentas de softwares com foco em manufatura inteligente, padronizando seus conceitos, termos, e a forma de coleta e tratamento de dados. A abordagem metodológica DSR (do inglês Design Science Research) é usada para guiar o desenvolvimento da pesquisa. A construção deste modelo ontológico, que integra tanto os dados coletados quanto as informações necessárias para a tomada de decisões, possibilita o controle da estimativa de uma falha antes dela ocorrer de uma forma mais autônoma. Os principais resultados do modelo ontológico construído são: uma ontologia flexível capaz de ser usada em vários tipos de máquinas mecânicas de diversos tipos de manufatura; a possibilidade de armazenar o conhecimento contido em normas internacionais, históricos de atividades das máquinas, e arquiteturas consolidadas no contexto do PHM, permitindo a constante atualização de dados dependendo de particularidades que cada processo produtivo pode conter, e finalmente, usando a linguagem SPARQL entrega-se informações que podem ser usadas para tomada de decisões em intervenções oportunas de manutenção nos equipamentos de uma indústria real. O modelo é demonstrado considerando o caso de uma bomba centrífuga que comprovou sua fidelidade, integridade, nível de detalhe, robustez e consistência, fornecendo informações anteriormente alimentadas por dados reais obtidos em empresas próximas. / Recent advances in smart manufacturing open up opportunities in industrial support, specifically in maintenance and physical asset management. This trend allows data collected from machines, when are in full operation, to interact with cyberspace computers through a communication network, thus forming the concept of cyber-physical systems (CPS). Besides, rapid advances in information and communications technologies provide tools for analysing data, in an increasingly rapid, autonomously, ubiquitous and in real time way, providing information that assists humans in making better decisions. In this sense, Prognostics and Health Management (PHM) of machines, is indicated as a promising application of Smart Manufacturing in the CPS contexto. Currently the PHM proposals found in the scientific literature are applied to specific cases and without a standardization of their implementation, preventing such approaches from being replicated in different manufacturing scenarios. Thus, the present work proposes the construction of an ontological model to assist in the implementation of the PHM in several manufacturing scenarios, to be harnessed in the future by software tools focused on intelligent manufacturing, standardizing their concepts, terms, and the form of data collection and processing. The DSR (Design Science Research) methodological approach is used to guide the development of the research. The construction of this ontological model, which integrates both the collected data and the necessary information for the decision making, allows the control of the estimate of a failure before it occurs in a more autonomous way. The main results of the ontological model are: a flexible ontology capable of being used on several types of mechanical machines of various types of manufacturing; the possibility of storing the knowledge contained in international standards, machine history of activities, and consolidated architectures in the context of the PHM, allows the constant updating of data depending on particularities that each productive process can contain, and finally, using the SPARQL language, it is given information that can be used for decisionmaking in timely maintenance interventions in the equipment of a real industry. The model is demonstrated considering the case of a centrifugal pump that proved its fidelity, integrity, level of detail, robustness and consistency, providing information previously fed by real data obtained in nearby companies.

This diploma thesis concerns issues of predictive and condition based maintenance system of machine tools with using a vibrodiagnostics. It studies and researches its impacts through the basic processes of the maintenance system and characterizes the vibration diagnosis as its tool and mean. There is also described a process of putting condition based maintenance into practice in the practical part of the thesis. The development is realized at Siemens Ltd. Brno with all its requirements and aspects such as a maintenance audit which means the decision on the suitability of condition based maintenance within the current maintenance system, technical analysis as a part of introduction of vibration diagnosis and the practical example of acquiring, recording and assessment of measured vibration. Prior to the end the economic evaluation of the planned predictive maintenance system and the design of the general model of development and implementation of the maintenance system into practice are included.

Master’s thesis is concerned with maintenance management in manufacturing companies focusing on TPM. The first part of the thesis deals with the topic theoretically and proposes possible solution in company Siemens Electric Machines s.r.o. based on system analysis. The practical part then describes the current state of maintenance management and recommend various measures to improve autonomous, scheduled and reactive maintenance in this company.

With the world economy becoming unpredictable, it has become a necessity for businesses to relook at the way they do business. The world has become competitive and companies that aim to become profitable have seen the need to find ways to improve efficiencies and increase productivity to stay relevant. There has been an adoption of strategies that are aimed at improving the efficiencies in companies such as Total Productive Maintenance (TPM). The strategy is aimed at improving equipment efficiencies and increase productivity through the transfer of certain skills from maintenance personnel to operators. The aim is that the operators perform some of the activities that the maintenance people used to do and they do the more complex tasks. By transferring these skills to operators there is constant cleaning, inspections and lubricating of equipment. This frees up time for maintenance people to do planning and other jobs that require time and higher skills levels. The implementation of these activities allows companies to tap into unused capacity that was always hidden by breakdowns and unplanned stops. The process however requires commitment from management and all stakeholders involved in the organisation. There are prescribed implementation processes that can be followed or companies can follow their own processes but the fundamentals of involving people from the onset must be followed. The involvement of stakeholders creates commitment at all levels and in order to sustain this initiative people must be committed to it. The inclusion of the activities transferred from maintenance people to operators, will reinforce the knowledge and habits required from operators and perhaps sustain the initiative. / MBA, North-West University, Potchefstroom Campus, 2015

With the world economy becoming unpredictable, it has become a necessity for businesses to relook at the way they do business. The world has become competitive and companies that aim to become profitable have seen the need to find ways to improve efficiencies and increase productivity to stay relevant. There has been an adoption of strategies that are aimed at improving the efficiencies in companies such as Total Productive Maintenance (TPM). The strategy is aimed at improving equipment efficiencies and increase productivity through the transfer of certain skills from maintenance personnel to operators. The aim is that the operators perform some of the activities that the maintenance people used to do and they do the more complex tasks. By transferring these skills to operators there is constant cleaning, inspections and lubricating of equipment. This frees up time for maintenance people to do planning and other jobs that require time and higher skills levels. The implementation of these activities allows companies to tap into unused capacity that was always hidden by breakdowns and unplanned stops. The process however requires commitment from management and all stakeholders involved in the organisation. There are prescribed implementation processes that can be followed or companies can follow their own processes but the fundamentals of involving people from the onset must be followed. The involvement of stakeholders creates commitment at all levels and in order to sustain this initiative people must be committed to it. The inclusion of the activities transferred from maintenance people to operators, will reinforce the knowledge and habits required from operators and perhaps sustain the initiative. / MBA, North-West University, Potchefstroom Campus, 2015

[ES] El contexto mundial actual de competitividad global hace que las empresas deban invertir muchos de sus recursos en ofrecer productos y servicios de calidad a precios competitivos. Desde hace muchos años el cliente demanda un producto de alta calidad y puede escoger entre muchas empresas de dónde obtenerlo, lo que hace que estas deban articular los mecanismos necesarios para ofrecer el nivel de calidad requerido en sus productos/servicios invirtiendo la menor cantidad de recursos posible. En este sentido, muchas empresas llevan años aplicando técnicas o herramientas de gestión de calidad, como por ejemplo Kaizen, control estadístico de calidad o diseño de experimentos por nombrar algunas, que les ayuden a alcanzar dicho nivel de calidad. Así, es ampliamente aceptada la existencia de una correlación entre la aplicación de técnicas de Gestión de Calidad Total (TQM) y la mejora del rendimiento empresarial que dará lugar a mayores beneficios. Sin embargo, a pesar de que se pueden encontrar numerosos trabajos científicos que relacionan la aplicación de TQM y el rendimiento empresarial, entendido éste como una parte concreta de la organización tal como producción o innovación, la cuantificación del efecto de TQM sobre el rendimiento empresarial global, utilizando un enfoque estratégico y equilibrado a través de un Cuadro de Mando Integral (CMI), es un tema de investigación actual no abordado hasta el momento y que se pretende desarrollar en esta Tesis Doctoral. Con este enfoque, las empresas obtendrán información adicional relevante para la toma de decisiones, respecto a cuáles son las técnicas y elementos de TQM que más impactan en su rendimiento organizacional estratégico y equilibrado, por lo que deberían ser priorizadas. Además, la aplicación de técnicas TQM genera directamente una serie de mejoras a nivel táctico-operativo en las organizaciones, por lo que las relaciones entre las técnicas TQM, el rendimiento empresarial estratégico medido y gestionado mediante un CMI y las mejoras empresariales mencionadas, son estudiadas y analizadas en profundidad en la presente Tesis Doctoral. A tal fin, en primer lugar se efectúa un estado del arte donde se analizan publicaciones científicas relevantes para demostrar la existencia de un hueco investigador. A continuación, se diseña una propuesta metodológica de seis fases para cuantificar el impacto de los elementos de TQM sobre el rendimiento organizacional, en el contexto de un CMI y en PYMES, siendo dichas fases: Fase 1. Definición de los elementos estructurales. Fase 2. Establecimiento del equipo de trabajo. Fase 3. Selección de los elementos. Fase 4. Determinación de la técnica MCDA. Fase 5. Aplicación de la técnica MCDA. Fase 6. Análisis de resultados. Entonces, las fases de la propuesta son aplicadas a una PYME del sector del petróleo en Ecuador y se presentan los resultados obtenidos en dicha aplicación. Finalmente, se establecen una serie de conclusiones generales y se enuncian unas líneas futuras de investigación. / [CA] El context mundial actual de competitivitat global fa que les empreses hagin d'invertir molts dels seus recursos a oferir productes i serveis d'alta qualitat a preus competitius. Des de fa molts anys el client demana un producte d'alta qualitat i pot escollir entre moltes empreses d'on obtenir-lo, el que fa que aquestes hagin de articular els mecanismes necessaris per oferir el nivell de qualitat requerida en els seus productes / serveis invertint el mínim de recursos possible. En aquest sentit, moltes empreses porten anys aplicant tècniques o eines de gestió de qualitat, com ara Kaizen, control estadístic de qualitat o disseny d'experiments per nomenar algunes, que els ajudin a aconseguir aquest nivell de qualitat. Així, és àmpliament acceptada l'existència d'una correlació entre l'aplicació de tècniques de gestió de qualitat total (TQM) i el rendiment empresarial entès aquest com la millora dels productes / serveis de l'organització que donarà lloc a majors beneficis. No obstant això, tot i que es poden trobar nombrosos treballs científics que relacionen l'aplicació de TQM i el rendiment empresarial, entès aquest com una part concreta de l'organització tal com producció o innovació, la quantificació de l'efecte de TQM sobre el rendiment empresarial, utilitzant un enfocament estratègic i equilibrat a través d'un quadre de comandament integral (CMI), és un tema d'investigació actual i que es pretén desenvolupar en aquesta tesi doctoral. Amb aquest enfocament innovador, les empreses obtindran informació addicional rellevant per a la presa de decisions, respecte a quines són les tècniques i elements de TQM que més impacten en el seu rendiment organitzacional estratègic i equilibrat, de manera que haurien de ser prioritzades. A més, l'aplicació de tècniques TQM genera directament una sèrie de millores a nivell tàctic-operatiu a les organitzacions, de manera que les relacions entre les tècniques TQM, el rendiment empresarial estratègic mesurat mitjançant un CMI i les millores empresarials esmentades, són estudiades i analitzades en profunditat en la present tesi doctoral. Amb aquesta finalitat, en primer lloc es fa un estat de l'art on s'analitzen publicacions científiques rellevants per demostrar l'existència d'un buit investigador. A continuació, es dissenya una proposta metodològica de sis fases per quantificar l'impacte dels elements de TQM sobre el rendiment organitzacional, en el context d'un CMI, en PIMEs, sent aquestes fases: Fase 1. Definició dels elements estructurals. Fase 2. Establiment de l'equip de treball. Fase 3. Selecció dels elements. Fase 4. Determinació de la tècnica MCDA. Fase 5. Aplicació de la tècnica MCDA. Fase 6. Anàlisi de resultats. A continuació, les fases de la proposta són aplicades a una PIME d'al sector de l'petroli a l'Equador i es presenten els resultats obtinguts en aquesta aplicació. Finalment, s'estableixen una sèrie de conclusions generals i s'enuncien unes línies futures de recerca. / [EN] The current worldwide competitive context makes that organization are struggling to be and become competitive. Since many years ago, customers demand high-quality products and he/she might choose from many different suppliers, which makes those enterprises must articulate the necessary mechanisms to offer such a quality level. In this sense, many organizations apply techniques of quality management, e.g., Kaizen, quality statistical control or design of experiments to mention some, to help them out reaching the required quality level. Then, it is widely accepted the existence of correlation between the application of Total Quality Management (TQM) techniques and organizational performance, understanding the latter as the improvement of the products/services that leads to higher benefits. However, even though it is possible to find many scientific works that relate the application of TQM and organizational performance improvement, relating this to a specific part of the organization such as production or innovation, the quantification of the effect of TQM on performance measurement, using a Balanced Scorecard (BSC) and, therefore, at the strategic and balanced level, is a current research topic, which is intended to be developed within this PhD Thesis. With this innovative approach, organizations would obtain additional relevant information for their decision-making processes about which the most relevant TQM techniques and tools are and should, therefore, be prioritized and improved. Besides, the application of TQM techniques directly generates some specific improvements at the tactic-operative level in organizations, and then the relationships among the TQM techniques, the organizational performance measured through a BSC, and the mentioned organizational improvements are studied and analyzed in this research. Then, a state of the art if firstly developed, analyzing relevant scientific publications, to identify the research gap. The next task is to design a six-phases methodological proposal to quantify the impact of TQM elements over organizational performance in SMEs within a BSC context, being the phases: Phase 1. Definition of the structural elements. Phase 2. Establishment of the work team. Phase 3. Selection of the elements. Phase 4. Determination of the MCDA technique. Phase 5. Application of the MCDA technique. Phase 6. Analysis of results. Then, these six phases are applied to a SME of the petroleum sector in Ecuador and the main results achieved are presented. Finally, the main conclusions are stated as well as some future research possibilities. / Andrade Arteaga, CA. (2022). Desarrollo de una propuesta metodológica para medir el impacto que tiene la aplicación de prácticas de Total Quality Management sobre el rendimiento organizacional en Pymes [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/181511 / TESIS