Revista de Matemática: Teoría y Aplicaciones, 1997
El algoritmo de Fisher es un algoritmo que calcula exactamente una particióń optima en k clases d... more El algoritmo de Fisher es un algoritmo que calcula exactamente una particióń optima en k clases de un conjunto Ω de n individuos a los que se les ha medido una variable real v. Tal clasificación que se obtiene, aunque no es necesariamenteúnica, eś optima respecto a v y, en el sentido de minimizar la inercia intra-clase, está formada por clases contiguas. Además, se estudia un criterio para estimar el númeroóptimo de clases en que puede clasificarse el conjunto de datos respecto a v. Se presenta una implementación computacional del algoritmo, así como algunos resultados numéricos.
In 1961, two human footprints were excavated from the Cuatro Cienegas region of Coahuila, Mexico,... more In 1961, two human footprints were excavated from the Cuatro Cienegas region of Coahuila, Mexico, but for decades were not studied scientifically or deposited in any museum. Consequently, knowledge of the locality where they were found was lost. Once the two tracks were relocated they found their way to the Museo del Desierto, Saltillo (Coahuila) where they were placed on
Abstract Internal fault detection in transformers provides early warning of electrical failure an... more Abstract Internal fault detection in transformers provides early warning of electrical failure and could prevent forced outages with the consequential costs. To detect and diagnose transformer internal faults it is required a model. This paper presents a methodology to ...
Abstract Internal fault detection in transformers provides early warning of electrical failure an... more Abstract Internal fault detection in transformers provides early warning of electrical failure and could prevent forced outages with the consequential costs. To detect and diagnose transformer internal faults it is required a model. This paper presents a methodology to ...
The periodontal probe remains the best clinical diagnostic tool for the collection of information... more The periodontal probe remains the best clinical diagnostic tool for the collection of information regarding the health status and the attachment level of periodontal tissues. The aim of this study was to evaluate intra- and inter-examiner reproducibility of probing depth (PD) measurements made with a manual probe. With the approval of an Ethics Committee, 20 individuals without periodontal disease were selected if they presented at least 6 teeth per quadrant. Using a Williams periodontal probe, three calibrated thesis-level students (k > 0.6) assessed PD at 6 sites per tooth, from the gingival margin to the bottom of the periodontal sulcus (rounded to the next 0.5 mm). Initial and repeated measurements were performed by the same three examiners. The intra-examiner agreement (± 1 mm > 90%) was 99.85%, 100%, and 100% for the three examiners, respectively. When the variables vestibular/lingual surfaces, mesial/distal surfaces, or superior/inferior jaws were evaluated, no significant differences in reproducibility were detected at the inter-examiner level (p < 0.05). At this level, the only significant differences observed were in the three examiners' measurements of the anterior and posterior sites. While high intra-examiner reproducibility was detected, inter-examiner level proved to be low. We can conclude that measurement of PD with a manual periodontal probe produced high reproducibility in healthy individuals. The operators position can affect the reproducibility of repeated measures of PD. Calibration and operator training, rather than operator experience, were fundamental for reproducibility. Other factors, such as individual technique and probing depth force, can affect inter-examiner reproducibility.
2015 IEEE International Conference on Industrial Technology (ICIT), 2015
The utilization of multi-cell converters, through the use of low voltage semiconductors, has perm... more The utilization of multi-cell converters, through the use of low voltage semiconductors, has permitted to implement medium and high voltage applications as PV farms and AC drives. In conventional AC drives, this converter requires an input multipulse transformer, which allows the low frequency harmonic cancellation that are generated by the three-phase diode rectifiers included in each cell. This multipulse transformer is bulky, heavy, expensive, and must be designed according to the number of power cells, making the transformer topology dependent.
A design procedure to select the components in a modular unified power-quality conditioner config... more A design procedure to select the components in a modular unified power-quality conditioner configuration based on single-phase cells is presented. The procedure is based on the fact that the load and distributor operating conditions range are known and it is required to impose stiff operating conditions in both the load side (regulation) and the point of common coupling side (power factor). Due to the arbitrary number of cells to be used in a modular approach, the proposed design procedure allows to select the power semiconductors and capacitors based on an economical evaluation, so an optimal number of cells can be chosen to minimize the overall power cell cost. This design procedure is well suited for modular configurations, where several degrees of freedom are not covered if just technical criteria are followed. Thus, an economic approach can be used to select the appropriate components. The rest of the devices, i.e., the transformers turn ratio and passive filters, are chosen using classical design methods based on technical issues such that the power cells operate within its permissible ratings. A practical case evaluation is presented for a medium voltage system application.
Revista de Matemática: Teoría y Aplicaciones, 1997
El algoritmo de Fisher es un algoritmo que calcula exactamente una particióń optima en k clases d... more El algoritmo de Fisher es un algoritmo que calcula exactamente una particióń optima en k clases de un conjunto Ω de n individuos a los que se les ha medido una variable real v. Tal clasificación que se obtiene, aunque no es necesariamenteúnica, eś optima respecto a v y, en el sentido de minimizar la inercia intra-clase, está formada por clases contiguas. Además, se estudia un criterio para estimar el númeroóptimo de clases en que puede clasificarse el conjunto de datos respecto a v. Se presenta una implementación computacional del algoritmo, así como algunos resultados numéricos.
In 1961, two human footprints were excavated from the Cuatro Cienegas region of Coahuila, Mexico,... more In 1961, two human footprints were excavated from the Cuatro Cienegas region of Coahuila, Mexico, but for decades were not studied scientifically or deposited in any museum. Consequently, knowledge of the locality where they were found was lost. Once the two tracks were relocated they found their way to the Museo del Desierto, Saltillo (Coahuila) where they were placed on
Abstract Internal fault detection in transformers provides early warning of electrical failure an... more Abstract Internal fault detection in transformers provides early warning of electrical failure and could prevent forced outages with the consequential costs. To detect and diagnose transformer internal faults it is required a model. This paper presents a methodology to ...
Abstract Internal fault detection in transformers provides early warning of electrical failure an... more Abstract Internal fault detection in transformers provides early warning of electrical failure and could prevent forced outages with the consequential costs. To detect and diagnose transformer internal faults it is required a model. This paper presents a methodology to ...
The periodontal probe remains the best clinical diagnostic tool for the collection of information... more The periodontal probe remains the best clinical diagnostic tool for the collection of information regarding the health status and the attachment level of periodontal tissues. The aim of this study was to evaluate intra- and inter-examiner reproducibility of probing depth (PD) measurements made with a manual probe. With the approval of an Ethics Committee, 20 individuals without periodontal disease were selected if they presented at least 6 teeth per quadrant. Using a Williams periodontal probe, three calibrated thesis-level students (k > 0.6) assessed PD at 6 sites per tooth, from the gingival margin to the bottom of the periodontal sulcus (rounded to the next 0.5 mm). Initial and repeated measurements were performed by the same three examiners. The intra-examiner agreement (± 1 mm > 90%) was 99.85%, 100%, and 100% for the three examiners, respectively. When the variables vestibular/lingual surfaces, mesial/distal surfaces, or superior/inferior jaws were evaluated, no significant differences in reproducibility were detected at the inter-examiner level (p < 0.05). At this level, the only significant differences observed were in the three examiners' measurements of the anterior and posterior sites. While high intra-examiner reproducibility was detected, inter-examiner level proved to be low. We can conclude that measurement of PD with a manual periodontal probe produced high reproducibility in healthy individuals. The operators position can affect the reproducibility of repeated measures of PD. Calibration and operator training, rather than operator experience, were fundamental for reproducibility. Other factors, such as individual technique and probing depth force, can affect inter-examiner reproducibility.
2015 IEEE International Conference on Industrial Technology (ICIT), 2015
The utilization of multi-cell converters, through the use of low voltage semiconductors, has perm... more The utilization of multi-cell converters, through the use of low voltage semiconductors, has permitted to implement medium and high voltage applications as PV farms and AC drives. In conventional AC drives, this converter requires an input multipulse transformer, which allows the low frequency harmonic cancellation that are generated by the three-phase diode rectifiers included in each cell. This multipulse transformer is bulky, heavy, expensive, and must be designed according to the number of power cells, making the transformer topology dependent.
A design procedure to select the components in a modular unified power-quality conditioner config... more A design procedure to select the components in a modular unified power-quality conditioner configuration based on single-phase cells is presented. The procedure is based on the fact that the load and distributor operating conditions range are known and it is required to impose stiff operating conditions in both the load side (regulation) and the point of common coupling side (power factor). Due to the arbitrary number of cells to be used in a modular approach, the proposed design procedure allows to select the power semiconductors and capacitors based on an economical evaluation, so an optimal number of cells can be chosen to minimize the overall power cell cost. This design procedure is well suited for modular configurations, where several degrees of freedom are not covered if just technical criteria are followed. Thus, an economic approach can be used to select the appropriate components. The rest of the devices, i.e., the transformers turn ratio and passive filters, are chosen using classical design methods based on technical issues such that the power cells operate within its permissible ratings. A practical case evaluation is presented for a medium voltage system application.
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