Esempi di domande teoriche

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Technologies for Information Systems Prof. L.Tanca Sample theoretical questions Unofficial file, questions gathered from exams. March 13, 2014 (25 minutes, each question 5 points) • Define the concepts of valid time and transaction time in temporal databases also describing their advantages and disadvantages. • Consider these data mining problems: classification and clustering. Define them, discuss the differences between the two problems and provide an application example for each of them. July 8, 2014 (25 minutes, each question 5 points) • Define Wrappers and Mediators, explain in which circumstances their use is advised in Data Integration and the way they work. Discuss the various types of Wrappers and Mediators that have been introduced during the course. • Define the two typical semantics of time in temporal databases (valid vs. transaction) also describing their difference, advantages and disadvantages. September 11, 2014 (25 minutes, each question 5 points) • Describe the dimensional fact model used in the data warehouse context and define its main elements. Provide a small example. • Same as question 2 (data mining) of March 13, 2014. September 29, 2014 (25 minutes, each question 5 points) • Describe dynamic data integration: techniques based on mediators and wrappers, techniques based on meta-models. Provide a small example. • Define the typical operations necessary in the multidimensional data model that is at the basis of data warehouses. February 13, 2012 (25 minutes) • Describe the two typical semantics of temporal data (valid and transaction time) also describing their advantages and disadvantages. • Describe the conflict analysis step in data integration; describe the most important classes of conflicts and provide a set of examples. February 10, 2016…