• Automated Quantification of Ki-67 on Gastric Epithelial Tissue based on Cell Nuclei Area Ratio 

  Blanco Solano, Austin; Siles Canales, Francisco; Alpízar Alpízar, Warner (2022)

  The objective was to develop an automated algorithm for the estimation of a protein (Ki-67) index based on cell nuclei area ratio of gastric epithelial tissue cells; for this purpose, digital histopathology images were ...

• A Novel Control System for Medium-Voltage Hexverter-Based Drives 

  Espinoza Bolaños, Mauricio; Donoso M., Felipe; Díaz D., Matías; Urrutia O., Matías; Cárdenas Dobson, Roberto (2020-09-23)

  In this paper, a novel control system for the Hexverter-based drive is proposed and analysed. Unlike previously proposed control schemes, the proposed one does not require the information of the machine variables to ...

• An Overview of Applications of the Modular Multilevel Matrix Converter 

  Díaz D., Matías; Cárdenas Dobson, Roberto; Ibaceta, Efraín; Mora, Andrés; Urrutia O., Matías; Espinoza Bolaños, Mauricio; Rojas, Félix; Wheeler, Patrick (2020-10-22)

  The modular multilevel matrix converter is a relatively new power converter topology suitable for high-power alternating current (AC)-to-AC applications. Several publications in the literature have highlighted the converter ...

• An Overview of Modelling Techniques and Control Strategies for Modular Multilevel Matrix Converters 

  Díaz D., Matías; Cárdenas Dobson, Roberto; Ibaceta, Efraín; Mora, Andrés; Urrutia O., Matías; Espinoza Bolaños, Mauricio; Rojas, Félix; Wheeler, Patrick (2020-09-08)

  The Modular Multilevel Matrix Converter is a relatively new power converter topology appropriate for high-power Alternating Current (AC) to AC purposes. Several publications in the literature have highlighted the converter ...

• Participación de cargas flexibles y recursos distribuidos de energía en el control primario de frecuencia de sistemas de potencia con baja inercia 

  Incer González, José Manuel (2022)

  Actualmente está en proceso una transición en la configuración de los sistemas eléctricos de potencia. En el esquema tradicional, la generación se concentra en las máquinas sincrónicas cuya operación involucra el uso de ...

• Performance Improvement of Alkaline–Electrolyte Aluminum–Air Batteries by NH4VO3-Based Additives 

  Atencio Estrada, Anyie Priscilla; Avilés, Juan Ramón; Montero Villalobos, Mavis Lili; González Flores, Diego; Ocón Esteban, Pilar (2022-02-09)

  Due to their high theoretical volumetric capacity, aluminum–air batteries are an up-and-coming alternative for energy storage in mobile applications. However, there are still several problems that need to be solved to make ...

• From the Air to the Ground: An Experimental Approach to Assess LiPo Batteries for a Second Life 

  Castro Fallas, Julio; Flores Valle, Carolina; González Flores, Diego; Quintero Cedeño, Vanessa Lisbeth; Pérez Mora, Aramis (2022-05)

  Many are the applications that use energy stored in lithium-ion (Li-ion) batteries to power themselves. Without a doubt this type of energy storage device has changed the way of living. However, a major concern regarding ...

• Robust energy system planning for decarbonization under technological uncertainty: From transport electrification to power system investments 

  Victor Gallardo, Luis Fernando (2022-08-25)

  This work develops energy system modeling tools that identify features of a robust energy policy: a policy that performs well relative to alternatives. The tools are based on the Open Souce Modeling System (OSeMOSYS), are ...

• A Comparative Study on Denoising Algorithms for Footsteps Sounds as Biometric in Noisy Environments 

  Caravaca Mora, Ronald; Brenes Jiménez, Carlos; Coto Jiménez, Marvin (2022-08-03)

  Biometrics is the automated identification of a person based on distinctive characteristics, such as fingerprints, face, voice, or the sound of footsteps. This last characteristic has significant challenges considering the ...

• Measuring the Quality of Low-Resourced Statistical Parametric Speech Synthesis Trained with Noise-Degraded Data Supported by the University of Costa Rica 

  Coto Jiménez, Marvin (2022)

  After the successful implementation of speech synthesis in several languages, the study of robustness became an important topic so as to increase the possibility of building voices from non-standard sources, e.g. historical ...

• Impacto fiscal de la descarbonización del transporte en Costa Rica y opciones de política para manejarlo 

  Rodríguez Zúñiga, Mónica; Victor Gallardo, Luis Fernando; Quirós Tortos, Jairo; Jaramillo, Marcela; Vogt Schilb, Adrien (2021-07)

  El Plan de Descarbonización de Costa Rica promueve el transporte público como principal opción de movilidad y fomenta la electrificación de la flota vehicular, lo cual habilitará múltiples beneficios socioeconómicos. Sin ...

• An Experimental Study on Speech Enhancement Based on a Combination of Wavelets and Deep Learning 

  Gutiérrez Muñoz, Michelle; Coto Jiménez, Marvin (2022-06-20)

  The purpose of speech enhancement is to improve the quality of speech signals degraded by noise, reverberation, or other artifacts that can affect the intelligibility, automatic recognition, or other attributes involved ...

• Identification of Costa Rican speaker’s age group based on acoustic vowel analysis 

  Yeom Song, Victor; Coto Jiménez, Marvin (2022-04-22)

  The identification of the speaker’s age is a fundamental task in human-computer interaction. In particular, the recognition of children has drawn attention from the research community due to the vulnerability of se persons ...

• 2D SLAM Algorithms Characterization, Calibration, and Comparison Considering Pose Error, Map Accuracy, CPU Usage, and Memory Usage 

  Trejos Vargas, Kevin Francisco; Rincón Riveros, Laura Camila; Bolaños Torres, Miguel Eduardo; Fallas Pizarro, José Ariel; Marín Paniagua, Leonardo José (2022)

  The present work proposes a method to characterize, calibrate, and compare, any 2D SLAM algorithm, providing strong statistical evidence, based on descriptive and inferential statistics to bring confidence levels about ...

• Producción artificial de habla: Síntesis de voz 

  Coto Jiménez, Marvin; Goddard Close, John; Martínez Licona, Fabiola (2015)

  A finales de la década de los 80, el estadounidense Raymond Kurzweil, inventor del primer sistema comercial que es capaz de tomar texto de un libro y pronunciarlo mediante habla artificial, escribió la obra “La era de las ...

• Ejemplo de generación y clasificación de bases de datos de imágenes simples 

  Coto Jiménez, Marvin (2015)

  Se documenta la creación de una base de datos para clasificación, que consiste de patrones de imágenes simples. Se presentan resultados de una clasificación de estas imágenes utilizando redes neuronales tipo perceptrón ...

• Minería de Datos: Concepto y Aplicaciones 

  Coto Jiménez, Marvin (2014)

  Se presenta la minería de datos como un conjunto de técnicas para obtener información útil y no evidente en datos de diversos tipos. Primero se revisa el concepto y su evolución, para repasar varias de las aplicaciones ...

• Inteligencia Artificial en la Creación Musical 

  Coto Jiménez, Marvin (2013)

  Se presenta el desarrollo de las técnicas de inteligencia artificial en procesos de creación musical, tanto para el apoyo de creación de obras a los compositores, como en proyectos que pretenden automatizar todo el proceso. ...

• HMM-Based Speech Synthesis Enhancement with Hybrid Postfilters 

  Coto Jiménez, Marvin; Goddard Close, John (2018)

  In this chapter, we introduce hybrid postfilters into speech synthesis, with the objective of enhancing the quality of the synthesized speech. Our approach combines a Wiener filter with deep neural networks. Several ...

• Evaluation of Mixed Deep Neural Networks for Reverberant Speech Enhancement 

  Gutiérrez Muñoz, Michelle; González Salazar, Astryd; Coto Jiménez, Marvin (2020)

  Speech signals are degraded in real-life environments, as a product of background noise or other factors. The processing of such signals for voice recognition and voice analysis systems presents important challenges. One ...

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