Browsing by Author "Medina, J"

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Automatic speech-to-text transcription in an ecuadorian radio broadcast context
(SPRINGER VERLAG, 2017-09-19) Sigcha, E; Espinoza Mejía, Jorge Mauricio; Medina, J; Saquicela Galarza, Víctor Hugo; Vega, F
A key element to enable the analysis and accessing to radio broadcast content is the development of automatic speech-to-text systems. The building of these systems has been possible given the current available of different speech resources, models, and open source services designed mainly for English language. However, the most of these tools have been migrated to other languages like Spanish for avoiding the creation of these systems from scratch. Despite existing efforts there is no clear evidence of the tools that can be used to convert audio to text in other dialects of Spanish. Also, the most of these systems are trained to consider a specific context, therefore, audio transcription systems personalized for a language and a specific context are needed. This article describes the implementation of an architecture oriented to automatic speech-to-text transcription applied on Ecuadorian radio broadcasters, using available free tools for performing audio segmentation and transcription. The selected tools were evaluated measuring their performance and facilities for adjusting to the defined architecture. At the end, a Web application was developed and its final performance was compared with IBM Watson speech to text service; the results show that the proposed system improves the accuracy and achieves a Word Error Rate around 10%. The obtained results allow to suggest the use of a free tools set in order to train models oriented to specific speech-to-text transcription scenarios.
Design of a Supervisory Control System for a Clinker Kiln Operation
(INSTITUTE OF ELECTRICAL AND ELECTRONICS ENGINEERS INC., 2015-07-14) Colina Morles, Eliezer; Falconí Abad, Mara Ximena; Medina, J; Morocho Zurita, Carlos Villie
The Clinker kiln is the core of the cement production process, which is a heavy infrastructure, where a mixture of limestone and clay undergoes physical and chemical transformations at high temperatures. The process has a very complex non-linear behavior, which hinders its control automatically. This article presents the design of a fuzzy logic-based supervisory system for control tasks upon the Clinker kiln operation [1]. The proposed supervisory system, which has been tested offline in an industrial kiln, uses process variables as the temperature in the burning area, the percentage of oxygen and the back-end temperature, to take appropriate control actions to face operating kiln conditions. The considered control variables in the design are the fuel flow to the burner, the air fan speed and the kiln rotational speed. As a result, the supervisory control system tests showed an improvement in kiln stability and clinker production.
Phenomenological modelling and computer simulation of a clinker kiln
(INSTITUTE OF ELECTRICAL AND ELECTRONICS ENGINEERS INC., 2016-10-12) Colina Morles, Eliezer; Falconí Abad, Mara Ximena; Medina, J; Morocho Zurita, Carlos Villie
This article uses a two-dimensional phenomenological model representing the dynamic behaviour of a clinker kiln, and includes another model to estimate the height of the solid material (crude) inside the kiln. These models are parameterized according to design specifications and operating conditions of a real industrial kiln, which belongs to a cement production plant. The whole model consists of 16 partial differential equations, one ordinary nonlinear differential equation and a set of algebraic equations, and is computationally simulated using the finite elements method. The model allows analyzing temperature profiles in the kiln, as well as qualitative characteristics associated with fractions of final components in the clinker production.