961 research outputs found

    Proceedings of SIRM 2023 - The 15th European Conference on Rotordynamics

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    It was our great honor and pleasure to host the SIRM Conference after 2003 and 2011 for the third time in Darmstadt. Rotordynamics covers a huge variety of different applications and challenges which are all in the scope of this conference. The conference was opened with a keynote lecture given by Rainer Nordmann, one of the three founders of SIRM “Schwingungen in rotierenden Maschinen”. In total 53 papers passed our strict review process and were presented. This impressively shows that rotordynamics is relevant as ever. These contributions cover a very wide spectrum of session topics: fluid bearings and seals; air foil bearings; magnetic bearings; rotor blade interaction; rotor fluid interactions; unbalance and balancing; vibrations in turbomachines; vibration control; instability; electrical machines; monitoring, identification and diagnosis; advanced numerical tools and nonlinearities as well as general rotordynamics. The international character of the conference has been significantly enhanced by the Scientific Board since the 14th SIRM resulting on one hand in an expanded Scientific Committee which meanwhile consists of 31 members from 13 different European countries and on the other hand in the new name “European Conference on Rotordynamics”. This new international profile has also been emphasized by participants of the 15th SIRM coming from 17 different countries out of three continents. We experienced a vital discussion and dialogue between industry and academia at the conference where roughly one third of the papers were presented by industry and two thirds by academia being an excellent basis to follow a bidirectional transfer what we call xchange at Technical University of Darmstadt. At this point we also want to give our special thanks to the eleven industry sponsors for their great support of the conference. On behalf of the Darmstadt Local Committee I welcome you to read the papers of the 15th SIRM giving you further insight into the topics and presentations

    Ergonomics in laparoscopic surgery: a work system analysis to reduce work-related musculoskeletal disorders across surgeons in Peruvian hospitals

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    Laparoscopic surgery, also called minimally invasive surgery, is a type of surgery in which the surgeon operates by viewing the surgery on a screen that projects images from a camera inserted into the patient's abdomen. Laparoscopic tools are long (usually up to 35 cm) and require fine motor skills and visual perception for manipulation, restricting the degrees of freedom to move within the patient. This restriction causes surgeons to operate with limited vision and restricted movement and force them to work with assistants who assist in conducting the cameras, acting as "the surgeons' eyes". Because of its minimally invasive nature, laparoscopic surgery is well accepted by patients but is challenging and complex for the surgeon. This is due to the restriction of movement and perception that forces surgeons to adopt awkward postures with high exposition, which increases the likelihood of work-related musculoskeletal disorders (WRMSD). WRMSDs are detrimental to surgeons' health and potentially may impact patient safety. Studies often highlight the problems of surgeons in high-income countries, whose solutions and clinical guides often cannot be applied to countries like Peru, which have severe deficiencies in its healthcare system. For this reason, the thesis proposes a contextualised investigation of the Peruvian surgical work system to investigate the main factors contributing to the development of WRMSD in laparoscopic surgeons, which may affect patient safety. The analysis aimed to propose possible recommendations to support redesigning the laparoscopic surgery work system in Peruvian hospitals. Five studies were developed to achieve the aims based on the Systems Engineering Initiative for patient safety model, an ergonomics model for healthcare systems analysis. The first three studies were developed parallel with a mixed convergent design approach concluding in an integrating study. The last two studies (study four and five) had a quantitative approach. The first study used a qualitative approach by collecting information through interviews with laparoscopic surgeons and observing their work in real surgeries. The second study adopted a quantitative approach through a questionnaire-based survey applied to 140 surgeons in Peru. The third study analysed the extent to which the postures adopted by surgeons in real surgeries increase the risk of WRMSD and their association with factors in the work system using the RULA method. The results of the three studies were integrated into an integrative study, concluding that the raised height of the operating table and other system factors related to tasks, person and technology raises the risk of WRMSD. Based on these results, the fourth study analysed the relationship between surgeons and operating tables to understand how many surgeons could reach suitable working heights. The study concluded that no operating table available in Peruvian hospitals nor in the market would be suitable for 90% of Peruvian surgeons. The tables were too high to accommodate surgeons with optimal working surface height to perform laparoscopic surgery. Then, a fifth study was conducted to determine an acceptable working height based on surgeon preferences and system factors and concluded that surgeons would accept a working height between 49 cm to 70 cm in height, which is lower than current operating tables. The lowest height was reached when surgeons had to operate on obese patients and perform intracorporeal suturing tasks. Finally, the thesis concludes with recommendations for redesigning working heights for 90% of the Peruvian medical population, considering work system elements of the Peruvian context

    Contributions to improve the technologies supporting unmanned aircraft operations

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    Mención Internacional en el título de doctorUnmanned Aerial Vehicles (UAVs), in their smaller versions known as drones, are becoming increasingly important in today's societies. The systems that make them up present a multitude of challenges, of which error can be considered the common denominator. The perception of the environment is measured by sensors that have errors, the models that interpret the information and/or define behaviors are approximations of the world and therefore also have errors. Explaining error allows extending the limits of deterministic models to address real-world problems. The performance of the technologies embedded in drones depends on our ability to understand, model, and control the error of the systems that integrate them, as well as new technologies that may emerge. Flight controllers integrate various subsystems that are generally dependent on other systems. One example is the guidance systems. These systems provide the engine's propulsion controller with the necessary information to accomplish a desired mission. For this purpose, the flight controller is made up of a control law for the guidance system that reacts to the information perceived by the perception and navigation systems. The error of any of the subsystems propagates through the ecosystem of the controller, so the study of each of them is essential. On the other hand, among the strategies for error control are state-space estimators, where the Kalman filter has been a great ally of engineers since its appearance in the 1960s. Kalman filters are at the heart of information fusion systems, minimizing the error covariance of the system and allowing the measured states to be filtered and estimated in the absence of observations. State Space Models (SSM) are developed based on a set of hypotheses for modeling the world. Among the assumptions are that the models of the world must be linear, Markovian, and that the error of their models must be Gaussian. In general, systems are not linear, so linearization are performed on models that are already approximations of the world. In other cases, the noise to be controlled is not Gaussian, but it is approximated to that distribution in order to be able to deal with it. On the other hand, many systems are not Markovian, i.e., their states do not depend only on the previous state, but there are other dependencies that state space models cannot handle. This thesis deals a collection of studies in which error is formulated and reduced. First, the error in a computer vision-based precision landing system is studied, then estimation and filtering problems from the deep learning approach are addressed. Finally, classification concepts with deep learning over trajectories are studied. The first case of the collection xviiistudies the consequences of error propagation in a machine vision-based precision landing system. This paper proposes a set of strategies to reduce the impact on the guidance system, and ultimately reduce the error. The next two studies approach the estimation and filtering problem from the deep learning approach, where error is a function to be minimized by learning. The last case of the collection deals with a trajectory classification problem with real data. This work completes the two main fields in deep learning, regression and classification, where the error is considered as a probability function of class membership.Los vehículos aéreos no tripulados (UAV) en sus versiones de pequeño tamaño conocidos como drones, van tomando protagonismo en las sociedades actuales. Los sistemas que los componen presentan multitud de retos entre los cuales el error se puede considerar como el denominador común. La percepción del entorno se mide mediante sensores que tienen error, los modelos que interpretan la información y/o definen comportamientos son aproximaciones del mundo y por consiguiente también presentan error. Explicar el error permite extender los límites de los modelos deterministas para abordar problemas del mundo real. El rendimiento de las tecnologías embarcadas en los drones, dependen de nuestra capacidad de comprender, modelar y controlar el error de los sistemas que los integran, así como de las nuevas tecnologías que puedan surgir. Los controladores de vuelo integran diferentes subsistemas los cuales generalmente son dependientes de otros sistemas. Un caso de esta situación son los sistemas de guiado. Estos sistemas son los encargados de proporcionar al controlador de los motores información necesaria para cumplir con una misión deseada. Para ello se componen de una ley de control de guiado que reacciona a la información percibida por los sistemas de percepción y navegación. El error de cualquiera de estos sistemas se propaga por el ecosistema del controlador siendo vital su estudio. Por otro lado, entre las estrategias para abordar el control del error se encuentran los estimadores en espacios de estados, donde el filtro de Kalman desde su aparición en los años 60, ha sido y continúa siendo un gran aliado para los ingenieros. Los filtros de Kalman son el corazón de los sistemas de fusión de información, los cuales minimizan la covarianza del error del sistema, permitiendo filtrar los estados medidos y estimarlos cuando no se tienen observaciones. Los modelos de espacios de estados se desarrollan en base a un conjunto de hipótesis para modelar el mundo. Entre las hipótesis se encuentra que los modelos del mundo han de ser lineales, markovianos y que el error de sus modelos ha de ser gaussiano. Generalmente los sistemas no son lineales por lo que se realizan linealizaciones sobre modelos que a su vez ya son aproximaciones del mundo. En otros casos el ruido que se desea controlar no es gaussiano, pero se aproxima a esta distribución para poder abordarlo. Por otro lado, multitud de sistemas no son markovianos, es decir, sus estados no solo dependen del estado anterior, sino que existen otras dependencias que los modelos de espacio de estados no son capaces de abordar. Esta tesis aborda un compendio de estudios sobre los que se formula y reduce el error. En primer lugar, se estudia el error en un sistema de aterrizaje de precisión basado en visión por computador. Después se plantean problemas de estimación y filtrado desde la aproximación del aprendizaje profundo. Por último, se estudian los conceptos de clasificación con aprendizaje profundo sobre trayectorias. El primer caso del compendio estudia las consecuencias de la propagación del error de un sistema de aterrizaje de precisión basado en visión artificial. En este trabajo se propone un conjunto de estrategias para reducir el impacto sobre el sistema de guiado, y en última instancia reducir el error. Los siguientes dos estudios abordan el problema de estimación y filtrado desde la perspectiva del aprendizaje profundo, donde el error es una función que minimizar mediante aprendizaje. El último caso del compendio aborda un problema de clasificación de trayectorias con datos reales. Con este trabajo se completan los dos campos principales en aprendizaje profundo, regresión y clasificación, donde se plantea el error como una función de probabilidad de pertenencia a una clase.I would like to thank the Ministry of Science and Innovation for granting me the funding with reference PRE2018-086793, associated to the project TEC2017-88048-C2-2-R, which provide me the opportunity to carry out all my PhD. activities, including completing an international research internship.Programa de Doctorado en Ciencia y Tecnología Informática por la Universidad Carlos III de MadridPresidente: Antonio Berlanga de Jesús.- Secretario: Daniel Arias Medina.- Vocal: Alejandro Martínez Cav

    (b2023 to 2014) The UNBELIEVABLE similarities between the ideas of some people (2006-2016) and my ideas (2002-2008) in physics (quantum mechanics, cosmology), cognitive neuroscience, philosophy of mind, and philosophy (this manuscript would require a REVOLUTION in international academy environment!)

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    (b2023 to 2014) The UNBELIEVABLE similarities between the ideas of some people (2006-2016) and my ideas (2002-2008) in physics (quantum mechanics, cosmology), cognitive neuroscience, philosophy of mind, and philosophy (this manuscript would require a REVOLUTION in international academy environment!

    街路景観のビッグデータとコンピューター視覚技術に基づく都市街路の空間知覚と物理的特徴に関する研究

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    Based on Streetscape big data and computer vision technology,the streets of typical coastal cities Qingdao and Fukuoka were selected as the site to explained the correlation between physical features and the perceptual features of urban streets to evaluation of the quality of street space. Combining the existing evaluation indexes of spatial perception from the expert and the public point of view , the study discussed the influence mechanism of physical parameters and perception. It proposed a method of locating street space design problems in coastal cities. The study not only will reflect the urban landscape current situation ,but also provide the basis to optimize the quality of urban street space design efficiently and large-scale. Moreover, it will promote the scientific development of urban construction and planning.北九州市立大

    2023- The Twenty-seventh Annual Symposium of Student Scholars

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    The full program book from the Twenty-seventh Annual Symposium of Student Scholars, held on April 18-21, 2023. Includes abstracts from the presentations and posters.https://digitalcommons.kennesaw.edu/sssprograms/1027/thumbnail.jp

    LIPIcs, Volume 261, ICALP 2023, Complete Volume

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    LIPIcs, Volume 261, ICALP 2023, Complete Volum

    Eco-Naturalism: re-evaluating the role of naturalism in contemporary eco-theatre

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    My thesis critically re-evaluates the role and potential of naturalism in contemporary eco-theatre. Challenging prevailing orthodoxies which dismiss naturalism as an eco-dramaturgical form on account of its perceived anthropocentrism, phallocentrism and conservatism, I argue that naturalism performs a vital—albeit frequently misunderstood—function within a range of contemporary plays and performances which foreground ecological issues. By introducing this fresh perspective on naturalism's eco-dramaturgical potential, I aim to stimulate a more nuanced critical debate than currently exists. My original contribution to knowledge centres around my formulation of the naturalistic spectrum, a new conceptual framework designed to help scholars, playwrights and theatre-makers square the spatiotemporal complexities of the ‘hyperobjects’ (Morton 2013) of global warming and ecological collapse with human scale theatrical representation. My case studies—plays and performances written and produced between 2011 and 2022—interrogate: overt eco-naturalism (Kirkwood’s The Children); symbolist eco-naturalism (Waters’ On the Beach); hyper eco-naturalism (Steiner’s You Stupid Darkness! and Baker’s The Antipodes); disrupted eco-naturalism (Macmillan’s Lungs and Churchill’s Escaped Alone) and covert eco-naturalism (Emmott and Mitchell’s Ten Billion and Hickson’s Oil). Using a methodology which combines close reading of texts with archive recordings and interviews with playwrights, directors and designers, my study reveals that naturalism performs a number of crucial eco-dramaturgical functions. Firstly, it presents the audience with an image of itself, vicariously suggesting ways to cope on a human scale with the suprahuman scale of ecological crisis. Secondly, it interrogates moral culpability, concerning itself with the long consequence of human actions. Thirdly, it highlights the deterministic effects of environment on character which, in the Anthropocene, reveals a degraded environment returning to haunt humans for their reckless custodianship of the planet. Lastly, it raises awareness of deep time, a concept which lies at the heart of ecological thinking
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