A Study of the Impact of Prognostic Errors on System Performance

Condition-based maintenance is growing in popularity as a means of improving equipment maintenance efficiency. Whether it be the maintenance of an airplane, a computer system, or any type of physical system, the prognostic tools associated with condition-based maintenance are subject to statistical error. These errors can lead to unnecessary preventive maintenance due to underestimation of system remaining life and unnecessary system failures due to overestimation of system remaining life. What is not clear is if these statistical errors outweigh the benefits of a condition-based maintenance policy. This study attempts to address this concern through the evaluation and comparison of three maintenance policies for a simple system. The maintenance policies are run-to-failure, scheduled preventive maintenance and condition-based maintenance. A discrete event simulation model is used to estimate the average time between successful missions for the system under each of these policies. An extensive set of numerical experiments is used to analyze system performance under a wide variety of operating conditions. The results suggest that condition-based maintenance can improve system performance as much as 10% to 15% beyond that achieved using scheduled preventive maintenance. However, the results also suggest that moderate statistical error can render condition-based maintenance inferior to scheduled maintenance and severe statistical error can render condition based maintenance inferior to run-to-failure. In addition to the results obtained by this study, the methodology used herein can aid maintenance managers in moving from a scheduled maintenance philosophy to a just-in-time maintenance philosophy; thereby increasing the availability of affected systems. Increasing the availability of any system is given considerable importance especially by industries that serve people. For example, in the airline and health industries the availability of a system is vital since any associated down time results in large profit losses and customer dissatisfaction. Overall, the method presented herein can help any kind of industry in developing a way for assessing their maintenance policies which could help them improve the availability of their systems in the future

Midnight Reflections about our own Northern Ventriloquist\u27s Skills

“Midnight Reflections about our own Northern Ventriloquist\u27s Skills” is articulated in the form of a podcast in a conversational style scripted by longtime collaborators composer and performer. It starts by cartographing the authors’ previous collaborative works until they approach their last project ensemble, Campo Amniótico [CA] (2021), work in which the feedback or Larsen plays a paramount role, making the artwork highly unstable and elusive. As a result, performers and composer are in constant trouble, stripped of their cognitive performativity by the once enhancer technology, that in CA becomes almost a threat. That’s when the podcast starts to interact with recorded extracts of philosophers Rosi Braidotti and Achille Mbembe, and psychologist Thirusha Naidu on issues concerning posthumanism, postcolonialism and technological escalation. By applying and discussing their theories in the field of artistic research and, more specifically, in that of contemporary music, the authors will situate CA as a post-human artwork that aims to tip the balance more towards subversion than the status quo. That is following Eve Sedwick\u27s precept, when she said twenty years ago with some disillusionment that the result of a work is usually always the same: a little subversive, a little hegemonic

The county general plan as a tool for the management of a middle size city Los Angeles

Este trabajo, trata sobre los distintos programas y proyectos concebidos en la actualización del Plan Regulador de Los Angeles, que se focaliza no tan sólo en las necesidades del área urbana de Los Ángeles, sino en la totalidad del territorio comunal. Producto de este proceso se refundió los cuatro instrumentos de planificación vigentes a la fecha, correspondiente a los planos reguladores de Los Ángeles, Millantú, Salto del Laja y San Carlos de Purén, generando un único marco regulador con 8 áreas urbanas independientes en el territorio, pero regidas por una ordenanza local y unos criterios de planificación comunes.La puesta en marcha de este instrumento de ordenación territorial, coincide con una etapa de gran dinamismo en el mercado inmobiliario de la ciudad, lo que ha permitido evaluar el comportamiento de las determinaciones del plan, validando los criterios de base del mismo y evidenciando los aspectos que se requiere modificar para el perfeccionamiento del instrumento.This article discusses different programmes and projects conceived for the actualisation of the County General Plan of Los Angeles (Chile) that focuses no only on the needs of the urban area of Los Angeles, but also on the whole county area. As a result of this process, the four planning instruments in force at that time – the General Plans of Los Angeles, Millantu, Salto del Laja and San Carlos de Puren – were merged in a single planning framework with 8 independent urban areas in the territory, ruled by a local regulation and common planning criteria.The starting of this instrument for territorial planning coincides with a stage of great dynamism of the state market, which allowed evaluating the effects of the plan, validating the basic criteria and identifying those aspects that require modifications for the improvement of the instrument

Mass distribution in galaxy clusters: strong lensing and dynamical mass analysis

In this thesis we study the total mass distribution in galaxy cluster through detailed analysis of strong gravitational lensing (SL) signatures and dynamical mass information. We perform FORS2/VLT spectroscopic observations for a sample of 29 new SL selected galaxy clusters from the RCSGA survey. Our spectroscopic analysis reveals 51 lensed galaxies that correspond to 34 background sources. From the redshift measurements we derive 689 cluster members, which are used to compute velocity dispersion and dynamical masses resulting in a mass range of 0.28 ≤ M200 /e+14 Mo/h ≤ 28.4. We use these results to derive robust mass measurements of our 29 clusters by combining SL constraints with dynamical masses. We combine the best-fitting model parameters from 27 of these clusters with the recent analysis of 19 X-ray selected clusters from the CLASH survey, and also with concentration parameter measurements from 27 SL selected clusters from the SGAS survey. This leads us to the largest robust dataset of concentration parameters for a controlled sample of 73 galaxy clusters. We find that for massive clusters (M200 ~ 8 × e+14 Mo/h), the concentration parameters are distributed around c200 = 4.3 ± 1.4, which is consistent with theoretical expectations within the intrinsic scatter. In contrast, for less massive clusters (M200 ∼ 1e+14 Mo/h), the concentrations are on average almost twice the mean expected value, even if the selection bias and projection effects are taken into account, resulting in a c − M relation with a strong dependence on the cluster mass, c ∝ M^α, where α = −0.52 ± 0.09. We find that this steep mass slope is mainly due to 6 RCSGA clusters and ∼ 16 clusters from the SGAS survey that are clearly describing a higher and steeper c − M relation with c = 8.9 ± 1.12 and α = −0.69 ± 0.09. This unusual relation is far from any theoretical expectation suggesting a bimodality in the c − M relation. The rest of the sample is characterized by a mass slope of α = −0.24 ± 0.11, reconciling simulation results with observations. We also develop the first algorithm able to automatically find multiple-image systems in galaxy clusters

En annorlunda design

Examensarbetet vill visa en design som beräknas ur hållfasthet, samt ur energimässig utgångspunkt. Designen ska visa på hur man kan bygga för en hållbar framtid, genom minskning av energianvändningen. Samt genom att skapa ett hem med möjlighet för uppgradering eller utveckling av huset. Val av material samt normer sätter prägel på dagens byggindustrier. Gör man rätt val kan man effektivisera resursnyttjandet. Enligt en historisk man vid namn Vitruvius från romartiden bör man ha olika egenskaper för att göra bra ifrån sig i sitt arbete. Husets design är tänkt att ta människan upp i höjd, samt att man kan nyttja denna sortens design vid exempelvis strandhus där man inte fått första parkett av utsikten utan hamnar bland husen bakom. Eller om man vill ha höjd för att motarbeta insiktsproblem, eller varför inte skapa altan på träden för att vila och eller ha gäster över för en fika. Avsikten är att kunna få nycklarna till ett hus där fantasin inte får direkta gränser

El concepto cultura en la sociedad moderna: una observación desde la teoría de sistemas sociales

EI objetivo de este trabajo es analizar el concepto de cultura desde la perspectiva de la teoria general de los sistemas sociales -propuesta por NikiasLulunann-, problematizando la interrogante de ¿como es posible la distincion de la cultura en la sociedad moderma? Conocemos la importancia de una pregunta formulada de tal modo, puesto que nos lleva por dos caminos sumamente importantes desde la teoria de sistemas. Metodologicamente, el primero se refiere a la conformacion de un problema autorreferente que trata sobre formas de sentido que se dirigen al sistema social, a partir del que se puede abordar el mundo. El segundo, implica reflexionar precisamente respecto de las condiciones de posibilidad de este problema, sus limitaciones y la forma en que genera descripciones autoimplicadas de la sociedad. Observar entonces sus rendimientos, en tanto eleccion y contingencia para enlazar recursivamente pasado y futuro, en cuanto memoria social, como "observacion de segundo orden" que admite la comparacion de lo diverso, desde un determinado punto de vista, problematizando sus limitaciones como perspectiva observacional, asi como los rendimientos que aporta la cultura a la sociedad como memoria

Synthesis of nine safrole derivatives and their antiproliferative activity towards human cancer cells

Indexación: ScieloSafrole from sassafras oil (Ocoteapretiosa Mez., Lauraceae), is an abundant natural product showing interesting functionality and chemical structure. Starting from safrole, nine derivatives were prepared and assessed for antiproliferative effect using different human cell lines. The in vitro growth inhibition assay was based on the sulphorhodamine dye to quantify cell viability. Some safrole derivatives, (2E')-3-(3',4'-methylenedioxi)phenyl acrylaldehyde (3) and 4-allyl-5-nitrobenzene-1,2-diol (4) presented better antiproliferative effect than the parent compound on two breast cancer cell lines (MCF-7 and MDA-MB-231) and one human colorectal cancer cell line (DLD-1) with IC50 values of 55.0 + 7.11 uM, 37.5 +2.65 uM and 44.0 + 6.92 µM, respectively, without toxicity towards dermal human fibroblast (DHF cells).http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072010000200016&nrm=is

Synthesis and cytotoxic activity of geranylmethoxyhydroquinone derivatives

Indexación: Web of Science; ScieloEl geranilo-2 ,4-sintético nuevo methoxyhydroquinone 1 y el conocido geranilo-4 ,5 methoxyhydroquinone- 2 se prepararon por sustitución electrófila aromática (EAS) reacciones entre geraniol y 1,3,5-trimethoxyphenol utilizando BF 3 · Et 2 O como un catalizador. Además, los nuevos derivados geranylmethoxyhydroquinones (3-6) se obtuvieron mediante transformaciones químicas de 1 y 2. Los compuestos se han evaluado por sus actividades citotóxicas contra PC-3 línea celular humana de cáncer de próstata, MCF 7-y humano MDA-MB-231 las células de cáncer de mama líneas y dengue hemorrágico cutánea fibroblastos humanos. IC 50 valores para los compuestos 1 y 5 varió en el nivel mu M 80.http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000300005&lng=es&nrm=is