Segmentación y clasificación en la toma de decisiones

Depto. de Estadística e Investigación OperativaFac. de Ciencias MatemáticasTRUEpu

A Brief Note on the Approach to the Conic Sections of a Right Circular Cone from Dynamic Geometry

Nowadays there are different powerful 3D dynamic geometry systems (DGS) such as GeoGebra 5, Calques 3D and Cabri Geometry 3D. An obvious application of this software that has been addressed by several authors is obtaining the conic sections of a right circular cone: the dynamic capabilities of 3D DGS allows to slowly vary the angle of the plane w.r.t. the axis of the cone, thus obtaining the different types of conics. In all the approaches we have found, a cone is firstly constructed and it is cut through variable planes. We propose to perform the construction the other way round: the plane is fixed (in fact it is a very convenient plane: z = 0) and the cone is the moving object. This way the conic is expressed as a function of x and y (instead of as a function of x, y and z). Moreover, if the 3D DGS has algebraic capabilities, it is possible to obtain the implicitequation of the conic

From computer algebra to discretized continuous logic

The aim of this paper is to present a new algebraic approach from computer algebra to a discretized continuous logic. It makes use of a previous model of p-valued logic (where p is a prime number) based on the use of Grobner bases of polynomial ideals. A five-valued logic (i.e., p = 5) with some modal operators has been considered as a compromise between precision and complexity of the polynomials involved. Therefore the continuous truth values are discretized into five intervals corresponding to the likelihood levels: impossible or very unlikely unlikely dubious probably almost sure or absolutely sure. It is therefore posible to obtain the likelihood level of any given logic formula. Moreover, it is possible to perform knowledge extraction and verification of small Rule Based Expert System whose knowledge is represented by this logic. An implementation in the computer algebra system Maple is included

An Accelerated-Time Simulation of Queues at Ticket Offices at Railway Stations

Although nowadays many railway tickets are bought online, still many are bought through rail appointed travel agents and ticket offices at stations. There are several works on microscopic and accelerated-time simulations, some of them related to the topic of this paper, treating passengers movements in railway stations (both of general purpose and also with a focus on specific topics like evacuation, stations design, ticketing, etc.). We focus on a very specific topic: modelling queuing at ticket offices at a main Spanish station where “AVE” (“High-Speed”), “Larga Distancia” (“Long-Distance”), “Media Distancia” (“Middle-Distance”), and “Cercanías” (“Suburban Services”) dedicated windows exist. The existence of “Last Minute” desks is also considered. The goal is to provide the user with a tool that allows to choose the best option for windows distribution along time, after different microscopic simulations based on given data and windows possible distribution are performed (as done in a previous work of one of the authors for airport terminals check-in counters). Special attention is paid to “Last Minute” windows and shared windows (for example simultaneously selling tickets for “Larga Distancia” and “Media Distancia”). Input is given by arrival curves or can be generated by the package. The output is the detailed situation of any window at any moment and the evolution of queues by train or window type. There are different further possible extensions of this work. The implementation has been developed in a computer algebra system in order to minimize the development time