A formula for the trace of symmetric powers of matrices

We present a formula for the trace of any symmetric power of a $n\times n$ matrix (with coefficients in a field) in terms of the ordinary powers of the matrix, an arbitrarily chosen linear function which vanishes on the identity matrix, and $n-2$ polynomial functions defined recursively

Coordinated Control of Energy Storage in Networked Microgrids under Unpredicted Load Demands

In this paper a nonlinear control design for power balancing in networked microgrids using energy storage devices is presented. Each microgrid is considered to be interfaced to the distribution feeder though a solid-state transformer (SST). The internal duty cycle based controllers of each SST ensures stable regulation of power commands during normal operation. But problem arises when a sudden change in load or generation occurs in any microgrid in a completely unpredicted way in between the time instants at which the SSTs receive their power setpoints. In such a case, the energy storage unit in that microgrid must produce or absorb the deficit power. The challenge lies in designing a suitable regulator for this purpose owing to the nonlinearity of the battery model and its coupling with the nonlinear SST dynamics. We design an input-output linearization based controller, and show that it guarantees closed-loop stability via a cascade connection with the SST model. The design is also extended to the case when multiple SSTs must coordinate their individual storage controllers to assist a given SST whose storage capacity is insufficient to serve the unpredicted load. The design is verified using the IEEE 34-bus distribution system with nine SST-driven microgrids.Comment: 8 pages, 10 figure

Digital Positioning Plan for Algramar Winery.

The purpose of this study is to analyse the context and situation of Algramar, a SME (small medium size enterprise) in the wine sector, under the principles of the organic winemaking. The main aim pursued on this dissertation is to support the company in the penetration of the online market, further describing the challenges it will face and the most consistent plan to maximize the performance efficiency. More specifically, we will provide Algramar with market information about the characteristics of the digital channel, and carry out a research on particular actions to build a consistent brand image online. We will hold on a compound of resources that will ease the path to attract traffic to our website, and turn it into actual sales. This plan involves search engine strategic knowledge, support of social media and mailing tracking techniques. The resulting conclusions will open a continuous improvement cycle to reach digital performance perfection

Time-domain harmonic state estimation of nonlinear load power systems with under-determined condition based on the extended Kalman filter

This contribution presents a time-domain methodology for harmonic state estimation of power systems with nonlinear loads based on the extended Kalman filter (EKF). The output variables measurements to be used in the state estimation algorithm are selected from the simulation of the propagated harmonics in the system with an under-determined condition of the measurement matrix. The state estimation results are compared against the actual time-domain system response; both results closely agree hence verifying the effectiveness of the EKF to solve the time-domain power system state estimation. Several sampling frequencies and measurement noise are applied to assess the effects on the state estimation process, the error covariance matrix, residuals and on the execution tim

VISION EMPRESARIAL DEL MEDICO VETERINARIO

The National Association of Universities and Institutions of Education Superior reports for cycle 2006-2007, to the Veterinary Medicine race within the sector of Farming Sciences where 6 000 enrolled students of the total of 307188 students of the national population of education exist superior, representing a 2%. In agreement with national statistics the Veterinary Medicine is an area of opportunity for the future professional. I am applied a survey to the students withdrawn in degree process, in the University Antonio Narro, to know the needs the labor market in which one evolves. Of withdrawn in the last the 4 years, 36% of the population were evaluated, reflecting that 52% carry out workings focused to the administrative area, 41% realises technical functions of the race, 4% carry out studies of posgrado and distribute chair and a 3% were unemployed. Reason why it is necessary to redesign the curriculum including the needs that can be detonating in the labor success of the withdrawn one, honoring the Strategic Administration like central axis, helped by other administrative tools which they assure the knowledge acquisition with enterprise approach, agreed to the needs of the globalised world.Evaluation, Redesign, Strategical Administration., Agribusiness,

Morphological and anatomical observations on the genus Scinaia (Nemaliales; Rhodophyta) from the Gulf of California, Mexico.

43rd European Marine Biology Symposium. Ponta Delgada, Açores, 8-12 de Setembro de 2008

A re-evaluation of Scinaia (Nemaliales, Rhodophyta) in the Azores.

Copyright © Springer-Verlag and AWI 2011.The genus Scinaia in the Azores is re-evaluated based on historical and recent collections. A combination of morphological and anatomical diagnostic characters was used for species segregation, and a key for Azorean species determination is presented. Anatomical information associated to the hair development is described for the first time for the genus. The occurrence of S. furcellata and S. interrupta is confirmed for the archipelago. The presence of S. acuta is reported for the first time in the Azores, representing a spread from Australia to the N-Atlantic and specifically into the Macaronesian region. Its occurrence in the archipelago and the Canaries is discussed as a possible introduction

Nonlinear Stability Analysis of the Classical Nested PI Control of Voltage Sourced Inverters

This note provides the first nonlinear analysis of the industry standard "partial decoupling plus nested PI loops" control of voltage sourced inverters. In spite of its enormous popularity, to date only linearization-based tools are available to carry out the analysis, which are unable to deal with large-signal stability and fail to provide estimates of the domain of attraction of the desired equilibrium. Instrumental to establish our result is the representation of the closed-loop dynamics in a suitable Lure-like representation, that is, a forward system in closed-loop with a static nonlinearity. The stability analysis is then done by generating an adequate Popov multiplier. Comparison with respect to linearization is discussed together with numerical results demonstrating non-conservativeness of the proposed conditions

Análisis de la resistencia a la compresión en elementos estructurales en obras sin presencia de un ingeniero civil en la ciudad de Trujillo, 2020

La presente investigación se realizó en la ciudad de Trujillo, en el Departamento de la Libertad, al norte del Perú; y contiene el análisis de la resistencia a la compresión en elementos estructurales en obras sin presencia de un ingeniero civil evaluado en el año 2020, donde se observó que el trabajo de elaboración de concreto se realiza sin asesoramiento técnico o de un especialista. Este estudio se inició realizando coordinaciones con cada uno de los propietarios de las viviendas unifamiliares evaluadas y con el responsable de la obra, luego se visitó cada obra durante el proceso de preparación y colocación del concreto; donde se evaluó las dosificaciones utilizadas, que permitió conocer el uso de una alta relación de agua/cemento de hasta 1.29. La resistencia promedio a la compresión del concreto a los 28 días fue de 76.56 Kg/cm2 la cual no alcanza la resistencia mínima establecida por el Reglamento Nacional de Edificaciones en la NTP E-0.60 (175Kg/cm2) y tampoco la resistencia para la cual algunos manifiestan su uso (210Kg/cm2). Como aporte analizo e identifico las posibles causas de la problemática en una baja resistencia, así como recomendaciones técnicas para elaborar el concreto y más

Comunicación, números y marketing

En la universidad aprendí la teoría, toda completa, con alegría porque me gustaba y la entendía, porque había crecido creyendo que las letras y sólo las letras eran lo mío, así crecí con cierto recelo a los números manteniendo la justa y necesaria relación con estos. Luego al terminar la universidad empecé a trabajar en diferentes sectores y aprendí todo lo que la universidad no logró enseñarme, por ejemplo, aprendí a entender mejor a los números, su importancia, su omnipresencia, las ventajas de conocerlos y trabajar con éstos; y no es que tenga una tendencia ni afición en particular por las estadísticas, sólo creo que he logrado llegar a una mejor comprensión de como los números pueden comunicar, en ocasiones, mejor que nosotros mismos y esto es algo que siempre procuro transmitir y enseñar.At the university I´d learned all the theory, with joy because i liked it and understood it, because I´d grown up believing that the letters and only the letters were my stuff, so i grew up keeping distance and the necesary relation with numbers. Later, when i finished university, i began to work in different sectors and learned everything that the university didn´t teach me, for example, i learned to understand numbers, their importance, their omnipresence, the advantages of knowing and working with them; and it's not that i have a particular tendency or fondness for statistics, I just think that I´ve managed to reach a better understanding of how numbers can communicate, sometimes even better than ourselves, and this is something that I always try to transmit and teach