Reimer Romero | Universidad de Carabobo (original) (raw)

Papers by Reimer Romero

Research paper thumbnail of Effect of a pseudogap on T c and on the superconducting order parameter

Research paper thumbnail of and The Abdus Salam International Centre for Theoretical Physics, Trieste, Italy

We further develop the pseudogap model proposed by J.L. Tallon and J.W. Loram, Physica C 349, 53–... more We further develop the pseudogap model proposed by J.L. Tallon and J.W. Loram, Physica C 349, 53–68 (2001). For the pseudogap order parameter we choose a particular form which reproduces the main features of the high temperature superconductor (HTSC) phase diagram which depends on carrier number, n. For fitting the key features of the cuprate oxides we have sensible parameters at our disposal, namely, a, which fixes the density where the pseudogap order parameter is maximum, α ′ which allows us to display the Tc vs n curve and Ego which gives us the value of the pseudogap. We have reproduced in a qualitative fashion the main details of the experimental data given in the work of Suryadijaya, T. Sasaqawa, and H. Takagi, Physica C 426–431, 402–406 (2005). Our main results are the following: 1. To have decreased the value of Tc with respect to the “free ” case, namely, Ego = 0, namely, when the pseudogap order parameter is not present. 2. To have obtained the maximum of Tc by choosing α...

Research paper thumbnail of THE ABDUS SALAM INTERNATIONAL CENTRE FOR THEORETICAL PHYSICS EFFECT OF A PSEUDOGAP ON Tc AND ON THE SUPERCONDUCTING ORDER PARAMETER

Research paper thumbnail of Análisis multiespectral y digital de los nevos melanocíticos adquiridos

Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales, Jun 28, 2018

Resumen El objetivo del presente trabajo fue encontrar las diferencias entre los distintos tipos ... more Resumen El objetivo del presente trabajo fue encontrar las diferencias entre los distintos tipos de nevos melanocíticos adquiridos con base en la información extraída de las imágenes multiespectrales. La dimensión fractal y la entropía se escogieron como medidas para distinguir entre los nevos (146 lesiones). El análisis de varianza (ANOVA unifactorial) considerando la dimensión fractal mostró diferencias significativas (p<0,05) entre los grupos, con mayor significación en la longitud de onda azul (p=7,87e-08), y menor en la roja. La medida de la entropía se comparada entre los pares de grupos mediante la prueba T de Student, y se encontraron diferencias entre los lunares benignos (U,C,I) y los displásicos (D), específicamente en los canales cyan (p UD =0,002, p CD =0,023, p ID =0,012) y rojos (p UD =0,0001, p CD =2,55E-5, p ID =0,005). El uso de imágenes multiespectrales, conjuntamente con las medidas de ordenamiento (dimensión fractal y entropía), permite caracterizar y diferenciar los grupos de nevos melanocíticos adquiridos, lo cual contribuiría al desarrollo de un tipo de evaluación dermatológica no invasiva y concluyente del ordenamiento de los nidos de melanina.

Research paper thumbnail of A Deformable Model to Search Characteristic Facial Points

A methodology is proposed to determine the positions of the characteristic facial points. The met... more A methodology is proposed to determine the positions of the characteristic facial points. The method is based on the Point Distribution Model, which estimates the most likely positions points. The search is refined with a discriminator, acting locally, around each point of the model; this discriminant model was achieved by training a Support Vector Machine with vectorized images in their histograms of oriented gradient (HoG). Then we aproximate de points by Thin Plate Spline by using a lambda parameters whose values were adjusted according to the local search errors. Models achieved performances that reached 90% in a cross-validation. Likewise, the strategy shows an error accumulated less than 10% in some characteristic points. The algorithm was evaluated with MUCT and BioID databases. This strategy would make digital morphological and anthropometric assessments to human face.

Research paper thumbnail of THE ABDUS SALAM INTERNATIONAL CENTRE FOR THEORETICAL PHYSICS EFFECT OF A PSEUDOGAP ON Tc AND ON THE SUPERCONDUCTING ORDER PARAMETER

We further develop the pseudogap model proposed by J.L. Tallon and J.W. Loram, Physica C 349, 53-... more We further develop the pseudogap model proposed by J.L. Tallon and J.W. Loram, Physica C 349, 53-68 (2001). For the pseudogap order parameter we choose a particular form which reproduces the main features of the high temperature superconductor (HT SC) phase diagram which depends on carrier number, n. For fitting the key features of the cuprate oxides we have sensible parameters at our disposal, namely, a, which fixes the density where the pseudogap order parameter is maximum, α ′ which allows us to display the T c vs n curve and E go which gives us the value of the pseudogap. We have reproduced in a qualitative fashion the main details of the experimental data given in the work of Suryadijaya, T. Sasaqawa, and H. Takagi, Physica C 426-431, 402-406 (2005). Our main results are the following:

Research paper thumbnail of Effect of a pseudogap on T c and on the superconducting order parameter

Research paper thumbnail of and The Abdus Salam International Centre for Theoretical Physics, Trieste, Italy

We further develop the pseudogap model proposed by J.L. Tallon and J.W. Loram, Physica C 349, 53–... more We further develop the pseudogap model proposed by J.L. Tallon and J.W. Loram, Physica C 349, 53–68 (2001). For the pseudogap order parameter we choose a particular form which reproduces the main features of the high temperature superconductor (HTSC) phase diagram which depends on carrier number, n. For fitting the key features of the cuprate oxides we have sensible parameters at our disposal, namely, a, which fixes the density where the pseudogap order parameter is maximum, α ′ which allows us to display the Tc vs n curve and Ego which gives us the value of the pseudogap. We have reproduced in a qualitative fashion the main details of the experimental data given in the work of Suryadijaya, T. Sasaqawa, and H. Takagi, Physica C 426–431, 402–406 (2005). Our main results are the following: 1. To have decreased the value of Tc with respect to the “free ” case, namely, Ego = 0, namely, when the pseudogap order parameter is not present. 2. To have obtained the maximum of Tc by choosing α...

Research paper thumbnail of THE ABDUS SALAM INTERNATIONAL CENTRE FOR THEORETICAL PHYSICS EFFECT OF A PSEUDOGAP ON Tc AND ON THE SUPERCONDUCTING ORDER PARAMETER

Research paper thumbnail of Análisis multiespectral y digital de los nevos melanocíticos adquiridos

Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales, Jun 28, 2018

Resumen El objetivo del presente trabajo fue encontrar las diferencias entre los distintos tipos ... more Resumen El objetivo del presente trabajo fue encontrar las diferencias entre los distintos tipos de nevos melanocíticos adquiridos con base en la información extraída de las imágenes multiespectrales. La dimensión fractal y la entropía se escogieron como medidas para distinguir entre los nevos (146 lesiones). El análisis de varianza (ANOVA unifactorial) considerando la dimensión fractal mostró diferencias significativas (p<0,05) entre los grupos, con mayor significación en la longitud de onda azul (p=7,87e-08), y menor en la roja. La medida de la entropía se comparada entre los pares de grupos mediante la prueba T de Student, y se encontraron diferencias entre los lunares benignos (U,C,I) y los displásicos (D), específicamente en los canales cyan (p UD =0,002, p CD =0,023, p ID =0,012) y rojos (p UD =0,0001, p CD =2,55E-5, p ID =0,005). El uso de imágenes multiespectrales, conjuntamente con las medidas de ordenamiento (dimensión fractal y entropía), permite caracterizar y diferenciar los grupos de nevos melanocíticos adquiridos, lo cual contribuiría al desarrollo de un tipo de evaluación dermatológica no invasiva y concluyente del ordenamiento de los nidos de melanina.

Research paper thumbnail of A Deformable Model to Search Characteristic Facial Points

A methodology is proposed to determine the positions of the characteristic facial points. The met... more A methodology is proposed to determine the positions of the characteristic facial points. The method is based on the Point Distribution Model, which estimates the most likely positions points. The search is refined with a discriminator, acting locally, around each point of the model; this discriminant model was achieved by training a Support Vector Machine with vectorized images in their histograms of oriented gradient (HoG). Then we aproximate de points by Thin Plate Spline by using a lambda parameters whose values were adjusted according to the local search errors. Models achieved performances that reached 90% in a cross-validation. Likewise, the strategy shows an error accumulated less than 10% in some characteristic points. The algorithm was evaluated with MUCT and BioID databases. This strategy would make digital morphological and anthropometric assessments to human face.

Research paper thumbnail of THE ABDUS SALAM INTERNATIONAL CENTRE FOR THEORETICAL PHYSICS EFFECT OF A PSEUDOGAP ON Tc AND ON THE SUPERCONDUCTING ORDER PARAMETER

We further develop the pseudogap model proposed by J.L. Tallon and J.W. Loram, Physica C 349, 53-... more We further develop the pseudogap model proposed by J.L. Tallon and J.W. Loram, Physica C 349, 53-68 (2001). For the pseudogap order parameter we choose a particular form which reproduces the main features of the high temperature superconductor (HT SC) phase diagram which depends on carrier number, n. For fitting the key features of the cuprate oxides we have sensible parameters at our disposal, namely, a, which fixes the density where the pseudogap order parameter is maximum, α ′ which allows us to display the T c vs n curve and E go which gives us the value of the pseudogap. We have reproduced in a qualitative fashion the main details of the experimental data given in the work of Suryadijaya, T. Sasaqawa, and H. Takagi, Physica C 426-431, 402-406 (2005). Our main results are the following: