Fault-tolerant observer design with a tolerance measure for systems with sensor failure

A fault-tolerant switching observer design methodology is proposed. The aim is to maintain a desired level of closed-loop performance under a range of sensor fault scenarios while the fault-free nominal performance is optimized. The range of considered fault scenarios is determined by a minimum number p of assumed working sensors. Thus the smaller p is, the more fault tolerant is the observer. This is then used to define a fault tolerance measure for observer design. Due to the combinatorial nature of the problem, a semidefinite relaxation procedure is proposed to deal with the large number of fault scenarios for systems that have many vulnerable sensors. The procedure results in a significant reduction in the number of constraints needed to solve the problem. Two numerical examples are presented to illustrate the effectiveness of the fault-tolerant observer design

Los procedimientos en el aprendizaje de la física

After an analysis of the function of the learning procedures we can identify some noticeable intellectual activities: skills and strategies. By appealing to some concrete examples we can see its importance in the process of both the teaching/learning of Physics at pre-university levels

The etnia of Penachíes in Lambayeque, Peru

Existen diversos elementos que prueban la existencia de este grupo étnico: su registro en las crónicas, leyendas y títulos comunales, así como diversos artículos publicados sobre esta materia. Su nombre no se debe a ningún hallazgos de estos cerámicos en un lugar determinado sino a la referencia que Cabello de Balboa haces de este grupo desde 1586. Pensamos que el estudio arqueológico de los restos esparcidos en las comunidades de Inkawasi, Penachí, Kañari, Colaya y Salas nos brindará más luces sobre este grupo étnico. Los relatos muestran las características de su cosmovisión y racionalidad

Parental Time Investments in Children: The Role of Competition for University Places in the UK

We use novel diary surveys coupled with universities' administrative student data for the last three decades to document that increased competition for university places at elite institutions in the United Kingdom contributes to explain growing gaps in time investments between college and non-college educated parents. Competition for university places in the UK grew significantly during the 1980s and early 1990s, and gradually diminished afterwards. We find that the gap in time investments by college and non-college educated parents and their children widened up precisely during this first period, especially in terms of human capital enhancing activities

The dry matter digestibility characteristics of tropical tree legumes using menke in vitro gas production technique

The amount of gas released when a feed was incubated in vitro with rumen fluid, was closely related to the digestibility of the feed. The experiment using Menke in vitro gas production was conducted to determine the dry matter digestibility of tropical tree legumes; Leucaena leucocephala, Flemingia macrophyla, and Gliricida sepium. The samples were collected from Institute of Animal Science farms of the University of the Philippines at Los Banos. The amount of gas produced were recorded at 3, 6, 12, 48 and 72 hours of incubation. To estimate the volume of gas, the equation of Tuah was adopted; while to describe the course of gas production, the equation of MCDONALD was used. The washing loss was not measured and assumed to be zero. Results showed that leucaena at 12 hours was the highest in the volume of gas produced (1.217 ml/g DM). There was a similarity of highly increase of the gas produced between gliricidia and flemingia at 24 hours of incubation i.e 1.60 ml/g DM and 1.60ml/g DM. The potential extent gas production at 72 hours (b value) and the gas production rate (c value) of three legumes were no significantly different. According to the logarithmic-curve of gas volume produced, leucaena tended to be the highest of increase in potential extent and the gas production rate. The different rate of gas production in related to incubation reflected the dry matter digestibility of the three legumes in the rumen.   Key words: In vitro gas production, dry matter digestibilit

Birth Timing and Neonatal Health.

We take advantage of a new natural experiment to evaluate the health effects of scheduling birth early for non-medical reasons on infant health. In 2010, the cancellation of a generous child benefit in Spain led may families to schedule birth early in order to remain eligible for the subsidy. We document that the affected cohort of children did not suffer any increase in birth complications or medical conditions right at birth, but were significantly more likely to be admitted to hospital during their second and third weeks of life, suggesting potentially persistent negative health effect