Γραφοθεωρητικές μεθοδολογίες για την δημιουργία συστημάτων σύστασης
Graphic and theoretical methods for creating recommendation systems
This thesis presents the Recommended Systems. In particular, the thesis is organized as follows. Chapter 1 constitutes the introduction of the thesis which describes the objective and the basic elements of the thesis. The Recommended Systems are defined in the second chapter. Moreover, the second chapter includes the procedure that the recommendation is done and the different types of recommendation. In addition, the systems that create recommendations, as well as, their advantages and drawbacks are, also, explained in chapter 2. Finally, chapter 2 introduces the hybrid systems that create recommendations and are, generally, more reliable than the traditional systems. An example of a hybrid system is, also, presented. The operation, the advantages and the disadvantages of known hybrid systems, which are usually used by other systems, are presented in more details in chapter 3. Additionally, figures and examples of hybrid systems are illustrated in chapter 3. Chapter 4 includes the implementation of an algorithm that takes as input a sample of 948 users and 1682 movies and outputs predicted values in a sparse matrix. The corresponding tables of the measurements are, also, presented in chapter 4. Finally, Chapter 5 concludes the thesis.