ViC-MAE: Self-Supervised Representation Learning from Images and Video with Contrastive Masked Autoencoders

We propose ViC-MAE, a model that combines both Masked AutoEncoders (MAE) and contrastive learning. ViC-MAE is trained using a global featured obtained by pooling the local representations learned under an MAE reconstruction loss and leveraging this representation under a contrastive objective across images and video frames. We show that visual representations learned under ViC-MAE generalize well to both video and image classification tasks. Particularly, ViC-MAE obtains state-of-the-art transfer learning performance from video to images on Imagenet-1k compared to the recently proposed OmniMAE by achieving a top-1 accuracy of 86% (+1.3% absolute improvement) when trained on the same data and 87.1% (+2.4% absolute improvement) when training on extra data. At the same time ViC-MAE outperforms most other methods on video benchmarks by obtaining 75.9% top-1 accuracy on the challenging Something something-v2 video benchmark . When training on videos and images from a diverse combination of datasets, our method maintains a balanced transfer-learning performance between video and image classification benchmarks, coming only as a close second to the best supervised method.Comment: More results on Video an Image datasets, ViC-MAE now supports training on videos and image

Public Financial Management Reforms: The Role of Ipsas in Latin-America

During the last 30years, many public administration reforms promoted by New Public Management have been undertaken. These reforms have spread to Latin-American countries and include changes in governmental accounting systems, where the implementation of International Public Sector Accounting Standards (IPSASs) has been a stimulus for modernization. This article aims to clarify the situation of IPSASs implementation in the Latin-American context as well as the stimuli for and effects of their implementation. The analysis shows that there is an emerging international trend to adopt IPSASs in Latin-American countries although at the same time, there are evident obstacles to achieving reform goals. In Colombia, reforms are still underway, and the usefulness of IPSASs to improve decision-making at an organisational level cannot be evaluated. Meanwhile, in Peru, the modernization is more rhetorical than real, and many efforts remain to be made for the effective implementation

Modeling and vibration mode analysis of a ball screw drive

Positioning systems for machine tools are generally driven by ball screws due to their high stiffness and low sensitivity to external perturbations. However, as modern machine tools increase their velocity and acceleration of positioning, the resonant modes of these systems could be excited degrading the trajectory tracking accuracy. Therefore, a dynamic model including the vibration modes is required for machine design as well as for controller selection and tuning. This work presents a high-frequency dynamic model of a ball screw drive. The analytical formulation follows a comprehensive approach, where the screw is modeled as a continuous subsystem, using Ritz series approximation to obtain an approximate N-degree-of-freedom model. Based on this model, the axial and angular components of each mode function are studied for different transmission ratios to determine the degree of coupling between them. After that, the frequency variation of each mode was studied for different carriage positions and different moving masses. Finally, an analysis of these results applied to controller design and parameter estimation is also presented.Fil: Vicente, Diego Alberto. Universidad Nacional de la Pampa. Facultad de Ingeniería; ArgentinaFil: Hecker, Rogelio Lorenzo. Universidad Nacional de la Pampa. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Villegas, Fernando Javier. Universidad Nacional de la Pampa. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Flores, Gustavo Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Las innovaciones en contabilidad gubernamental en latinoamérica: el caso de colombia

En este trabajo se aborda la reforma de la contabilidad gubernamental en Colombia−iniciada en 1991 y que se extiende hasta la actualidad− buscando contribuir a la comprensiónde la génesis y del desarrollo del Sistema Contable Público Colombiano. Un elemento novedosoreside en documentar parte del proceso de adaptación de las International Public Sector AccountingStandards, IPSAS, a un contexto específico. Así, la pregunta central del documento es: ¿Puedeconsiderarse el proceso desarrollado en la contabilidad gubernamental en Colombia como unainnovación? Desde un enfoque descriptivo y analítico, soportado en documentos públicos y enfuentes secundarias, los autores caracterizan lo acontecido siguiendo el modelo del proceso dereforma de la gestión financiera propuesto por Lüder (2002). Se analizan las variables estructurales,comportamentales e instrumentales que han participado en el proceso, y se ubica el estado de lareforma. Además, se identifican algunos motivadores y obstáculos en la adopción–adaptación deinnovaciones tales como las IPSAS

Fracture toughness and temperature dependence of Young's modulus of a sintered albite glass

Albite glass is an important component in many ceramic compositions, often used as liquid phase during the sintering process. Nevertheless, in spite of its almost ubiquous presence in the final microstructure of these compositions, some properties such as Young's modulus or fracture toughness have not been extensively studied in literature. This paper presents an experimental study on a sintered albite glass obtained from sodium feldspar powder. The microstructure of the resultant amorphous solid was analyzed via scanning electron microscopy and X-ray diffraction. Fracture toughness was determined at room temperature from the critical stress intensity factor (KIC) with a three point bending single-edge notched test (SENB). Young's modulus and coefficient of thermal expansion (CTE) were measured as a function of the temperature. A value of CTE of 6.6 × 10− 6 °C− 1 within the temperature range 300–500 °C was found. Young's modulus values of the albite glass were within the range from 63.6 to 65.2 MPa. SENB tests revealed a fracture toughness of KIC = 0.78 ± 0.06 MPa m1/2, which is of similar value to those found for borosilicate and soda-lime glasses

Relationship between Young's modulus and temperature in porcelain tiles

A focused research was conducted on samples prepared from an industrial porcelain tile composition containing quartz, used to produce ceramic floor tiles, with the aim of evaluating the variation of fired specimens’ Young's modulus with temperature. These samples were fired in controlled laboratory conditions so that specimens with pre-existing cracks were obtained and subject to non-destructive in situ thermo-mechanical measurements (impulse excitation technique) in the 22–700 °C temperature range during heating and cooling processes in order to find evidences to explain the hysteresis phenomenon in the Young's modulus versus temperature curve. The observed irreversible Young's modulus may be directly related to the pre-existent cracks that on heating and cooling are closed and opened up respectively, changing thus the Young's modulus which is well characterized by a hysteresis cycle

AFDX networks simulation-based evaluation system

Aircraft on-board systems, including navigation equipment, sensors and actuator, among others, present an increasingly demanding requirements on the avionics data communication networks. Moreover, the safety-critical needs of avionics make network requirement even more stringent. Also, prototyping and testing different network architectures and configurations pose a challenge due to the cost of the equipment. Furthermore, classical performance assessment relies solely on worst-case assessment, which do not provide detailed feedback. For these reasons, an evaluation system is proposed focusing on the simulation of Avionics Full-Duplex Switched Ethernet (AFDX) in order to help decrease the costs of the development of such networks.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

El rey D. Pedro I, y los conjurados : drama en cuatro actos,

Para representarse en el Teatro de Variedades, el año de 1855Copia digital. Madrid : Ministerio de Cultura. Dirección General del Libro, Archivos y Bibliotecas, 2010Pie de imprenta tomado del colofónSign.:1-2(4º)Texto a dos col.Colección de comedias representadas con éxito en los Teatros de Madri

Desempeño laboral en trabajadores de boticas de Huancayo en periodo de pandemia, 2021

El estudio se trazó como meta determinar las características del Desempeño laboral en trabajadores de boticas de Huancayo, en periodo de pandemia, 2021. Para ello se utilizó el método científico, de carácter observacional, correspondiendo a una investigación básica, y transversal, de nivel descriptivo. La población estuvo constituida por todos los trabajadores de boticas de Huancayo, entre los meses de octubre del año 2021 a abril del año 2022. La muestra la conformaron 384 personas que laboraron en 85 boticas, a quienes se les escogió aplicando un muestreo de tipo no probabilístico intencionado, mediante una encuesta con ayuda de un instrumento para evaluar el Desempeño laboral, el mismo que fue validado (juicio de expertos) y sometido a prueba de confiabilidad (prueba piloto). Finalizado el estudio, se determinó que, respecto a Proactividad, la variable Desempeño laboral fue alta en 65,1% de casos; hubo 69,0% de alto Desempeño laboral en relación a la dimensión Capacidad de servicio; respecto a la dimensión Conocimiento, éste fue alto 89,1% de encuestados y en referencia a la dimensión Diligencia en el trabajo fue alto en 71,6% de casos. Se concluye que el Desempeño laboral fue alto en 94,8% de trabajadores encuestados, ante lo cual se recomienda que los administradores de farmacias y boticas apliquen permanentemente estrategias que mejoren el Desempeño laboral en relación a todas las dimensiones de la variable evaluada

Estimation of the age of majority through radiographic evaluation of the third molar maturation degree

Although the third molar is the tooth with the greatest anatomical and developmental variability, some authors consider it important to estimate whether a subject is of legal age or not. The Demirjian?s technique is the most widely used tool to estimate dental age and was therefore used in our study to assess possible correlation between the age of majority and the maturational degree of the lower third molars, evaluated through radiographic images. This observational transversal study was conducted on 180 panoramic radiographs from consecutive patients. The degree of maturation of the lower third molar was independently classified by two observers, according to the Demirjian´s maturational stage method. A total of 180 patients ? 65 men (36.12%) and 115 women (63.88%) ? were included (mean age 21.6 years; standard deviation 5.2). The age range of our subjects corresponded to maturational stages D to H in the Demirjian?s classification. A logistic regression analysis showed that subjects classified into the highest maturational stage H had a significantly higher probability of being considered of legal age by both observers, as compared with subjects in the lowest stage D. Inter-observer agreement was very high. Gender predictive capacity was not observed. Our results showed that subjects with the lower third molars in the highest maturational stage could be estimated to be older than 18 years and therefore considered of legal age, a finding also reported by other authorsThe Demirjian´s tooth maturational stage method, applied to the lower third molars, can be reliably used to estimate whether an individual is of legal age (18 years or older). High concordance between different observers using this method can be expected