Pedro Corcuera

Some applications of scalar and vector fields to geometric processing of surfaces

In this paper, two geometric processing problems are considered: (1) point on a surface nearest to an external point, and (2) silhouette curve of a surface when observed from a given point. Problem (1) is solved by constructing gradient curves on the surface associated with a distance scalar field. Problem (2) appears as the intersection of surfaces (implicit case), or as tracing a plane curve (parametric case). Formulations are geometric-differential, and lead to explicit, first-order systems of ordinary differential equations (ODEs), with initial conditions that can be efficiently integrated by standard numerical methods. The methodology allows us to deal with both implicit and parametric representations, these having any functional structure for which the differential statements are meaningful.

Vertical Partitioning Algorithms in Distributed Databases

Data distribution is a crucial problem affecting the cost and efficient use of these systems. The problem is further exacerbated by the lack of methods and support tools for the design of distributed databases. This paper outlines some of the main techniques currently used for data distribution, such as vertical partitioning and replication. Two vertical fragmentation methods are described, the classic NAVATHE method and the newer FURD method, as well as the two proposed in this paper, the FURD-FDEZ and the FURD WITH REPLICATION methods.

Representation and Analysis of a Dynamical System with Petri Nets

Petri nets are gaining increased popularity among the scientific community during the last few years. They provide a simple and very intuitive graphical model for concurrency, parallelism and synchronization, and have a solid mathematical foundation as well as many analysis methods available. Because of these reasons, they have become a classical modeling tool for discrete event systems. In this paper we apply the Petri nets paradigm to represent and analyze a discrete dynamical system: a pressure tank. In particular, we are interested to determine the possible scenarios of a failure of the system and some associated behaviors. All computations have been done using a Mathematica package, which is also briefly described in this paper.

Design and Implementation of Multimedia Environment for Simulation

The importance of simulation in all fields is widely recognized due to the impact it has on design, production and engineering. This paper presents a design methodology aimed at developing multimedia interfaces for the simulation of industrial processes, using an object oriented point of view. A division of its composing elements into three functional blocks is proposed. The design methodology is based on the carrying out of a series of interrelated tasks, which from a software engineering perspective, gives maximum performance, both for the development process and its subsequent updating.

Training Simulator for Garoña Nuclear Power Plant

The training of Nuclear Power Plant Operators is the utmost importance for the proper running of Plants, with the strictest of security conditions. Given the specific characteristics of this type of energy, the training of operators can be carried out only by means of simulators.

MULTIMEDIA ENVIRONMENTS: DESIGNS FOR SIMULATION

The importance of simulation in all fields is widely recognized due to the impact it has had on design, production, and engineering. Currently, computer technology offers rapid solutions and graphics facilities that contribute to the development and improvement of complex simulation programs and their user interfaces. This paper presents a methodology aimed at developing graphic interfaces for the simulation of industrial processes and with the possibility of extending the scope into the area of control. The first part summarizes the simulation process technique and the problem of the user interface design from an ergonomic perspective. The second part describes the design of the user interface. First, the kind of process to be simulated is identified. Focusing on the objects that are to be represented, these are named with their respective actions in the process and the interface. Finally, a prototype of process simulation of a nuclear plant is presented.

Some Problems in Geometric Processing of Surfaces

This paper addresses two interesting problems in geometric processing of surfaces: (1) the determination of the curves on a surface having a constant angle with a prescribed constant direction (helical curves) and (2) the construction of the curve of contact between the surface and the cone circumscribing the surface, with its vertex at the observation point (silhouette curves). Both problems are formulated by using geometric and differential arguments leading to initial value problems of systems of explicit first-order ordinary differential equations that can be efficiently solved through standard step-by-step numerical integration methods. For each problem, the interesting cases of surfaces given in implicit and parametric form are discussed. Some illustrative examples show the good performance of the proposed methods.

Distributed Simulation with Multimedia Interface

The training of the personnel plays a major role in the security and reliability of many industrial processes. In order to fulfil this objective it is necessary to develop applications that support distributed interactive simulation with an interface near the real world. This paper describes such type of application during the development of a training simulator prototype for a nuclear power plant. The simulator is based on a client/server architecture that allows the execution on different machines in a network and many users to participate in the same simulation. The interface was designed to support the interaction of the operators with the simulator through touch screens with high fidelity displays of the control room developed using the component technology. The main features of the simulator are the distributed execution of the models using inexpensive hardware and the flexibility of design and maintenance of the interface.

From a graphical interface to a full scope training simulator

TSG++, a full scope training simulator with an interface entirely made up of soft panels, has been developed for a Spanish nuclear power plant. The simulation environment is OpenSim NT by RNI Technologies. The graphical interface, which in cludes fifty-seven PCs and monitors in its present configuration, has been developed using component software technology. The operators interact with the simulator by means of touch-screens. Specific appli cations give the instructor full control of all the computers and displays from his own console in a simple manner. An optimum choice of hardware for visualization and interaction, in terms of cost and performance, resulted in a facility much less expen sive than the classic hard panels replica simulators. Other benefits of the soft panels approach include automatic switch reposition and tagging, configura tion flexibility, low maintenance requirements and capability to support multiple users distributed across the company intranet. After exhaustive validation and testing, the training sessions are being con ducted successfully.