Manizales, which contributed with the administrative requirements in order to fulfill the objectives of the research and helped me with their knowledge and expertise in many of the stages.Finally, but most important, I have to thank my family, my parents Ramiro and Maria Cristina, my brothers and nephews, and especially, my wife Daniela who supported me all along this journey, and my twin sons Emilio and Gabriel who at their tender age patiently waited hours and days while his father spent time in front of the computer. They are my motivation, my reason to continue pursuing new challenges in life, and my dearest treasure. This thesis is dedicated to the memory of my late grandfather Eduardo Arango. Without his legacy this work would be of no practical relevance to our region.