115 research outputs found
Discours évaluatif et suivi d'opinion
No full text@inproceedings{CN-VERNIER-07, author = {M. Vernier and S. Ferrari and D. Legallois}, title = {{Discours évaluatif et suivi d'opinion}}, booktitle = {{Actes des 5èmes Journées de la Linguistique de Corpus}}, year = {2007}, editor = {G. Williams}, month = {septembre}, address = {Lorient, France}, publisher = {Université de Bretagne-Sud}, annote = {CN} }National audienc
Non-analytic behavior of the Loschmidt echo in XXZ spin chains: Exact results
No full textWe address the computation of the Loschmidt echo in interacting integrable spin chains after a quantum quench. We focus on the massless regime of the XXZ spin-1/2 chain and present exact results for the dynamical free energy (Loschmidt echo per site) for a special class of integrable initial states. For the first time we are able to observe and describe points of non-analyticities using exact methods, by following the Loschmidt echo up to large real times. The dynamical free energy is computed as the leading eigenvalue of an appropriate Quantum Transfer Matrix, and the non-analyticities arise from the level crossings of this matrix. Our exact results are expressed in terms of “excited-state” thermodynamic Bethe ansatz equations, whose solutions involve non-trivial Riemann surfaces. By evaluating our formulas, we provide explicit numerical results for the quench from the Néel state, and we determine the first few non-analytic points. © 2018 The Author(s
Opimisation techniques for the design of a DC-excited vernier reluctance machine operated as a synchronous condenser
No full textThesis (MEng)--Stellenbosch University, 2023.ENGLISH ABSRACT: With the growth in the renewable energy sector, and with power electronic devices failing to provide the required grid strength, there has been a renewed interest in the synchronous condenser industry. Synchronous condensers are used to provide rotational inertia, short circuit strength, low voltage ride through and reactive power compensation to the grid. However, synchronous condensers are also known for high operational losses and costly maintenance requirements. The DC-excited vernier reluctance machine was recently proposed as an alternative to address some disadvantages of conventional wound rotor synchronous condensers [1]. This study continues the research by focusing on the development of an optimisation technique that optimises the reactive power performance of the DC-excited vernier reluctance machine as a synchronous condenser for a fixed machine volume. An optimum selection criterion for a synchronous condenser from the optimisation Pareto front is proposed based on the relationship between the required reactive power and an efficiency indicator of reactive power per loss. As part of the optimisation, a technique is developed that estimates the core losses of the dc-excited vernier reluctance synchronous condenser within a single finite element solution. This technique is developed to reduce the computation time of the optimisation. Furthermore,
the performance of the optimised DC-excited vernier reluctance synchronous condenser is analysed using two finite element packages. The frozen permeability technique is adopted and used to calculate the inductance and performance parameters of the machine. In this thesis the author applies the optimisation technique to DC-excited vernier reluctance synchronous condensers with different volumetric sizes and kvar-ratings as part of a case study. As part of this case study, a 300 Mvar wound-field flux-switching machine is optimised with the newly developed optimisation technique and compared to a dc-excited vernier reluctance synchronous condenser of the same volumetric size. The author also includes a conventional four-pole synchronous condenser in the case study that compares
the reactive power per loss and per volume. These machines are then compared, by mainly considering their reactive power per loss and reactive power per volume. Finally, a 55 kvar DC-excited vernier reluctance synchronous condenser prototype is built as part of the study. This prototype is used for the experimental data validation of the simulated results.AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar.Master
Vernier perceptual learning transfers to completely untrained retinal locations after double training: A "piggybacking'' effect
No full textPerceptual learning, a process in which training improves visual discrimination, is often specific to the trained retinal location, and this location specificity is frequently regarded as an indication of neural plasticity in the retinotopic visual cortex. However, our previous studies have shown that "double training'' enables location-specific perceptual learning, such as Vernier learning, to completely transfer to a new location where an irrelevant task is practiced. Here we show that Vernier learning can be actuated by less location-specific orientation or motion-direction learning to transfer to completely untrained retinal locations. This "piggybacking'' effect occurs even if both tasks are trained at the same retinal location. However, piggybacking does not occur when the Vernier task is paired with a more location-specific contrast-discrimination task. This previously unknown complexity challenges the current understanding of perceptual learning and its specificity/transfer. Orientation and motion-direction learning, but not contrast and Vernier learning, appears to activate a global process that allows learning transfer to untrained locations. Moreover, when paired with orientation or motion-direction learning, Vernier learning may be "piggybacked'' by the activated global process to transfer to other untrained retinal locations. How this task-specific global activation process is achieved is as yet unknown.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000345768300012&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701OphthalmologySCI(E)[email protected]; [email protected]
Using dataloggers in physics teaching (focused on Vernier experimental system)
No full textTitle: Using dataloggers in physics teaching (focused on Vernier experimental system) Author: Petr Kácovský Department: Department of Physics Education Supervisor: Mgr. Pavel Böhm Supervisor's e-mail address: [email protected] Abstract: Modernizing equipment enables schools to involve advanced computer- aided systems in physics teaching. This work especially focuses on systems capable of recording and storing measured data for later evaluation - the dataloggers. The introduction of this work is devoted to a survey among physics teachers that should investigate what form of instructions they prefer; then a brief search of existing ma- terials follows. The main part of the work consists of newly created instructions for experiments with dataloggers of the Vernier experimental system, primarily designed to serve tea- chers to implement physics experiments in their teaching. The instructions always include a description how to prepare and undertake the measurement, how to process the measured data and what questions and tasks for students can be connected with this part of physics. Experiments described in this work mainly focus on secondary school thermodynamics (or more precisely on molecular physics and thermals) and their thematic intersection is energy, its forms, transmission and conservation
Vernier Sound Level Meter
No full textKäesoleva bakalaureusetöö eesmärgiks oli luua põhjalik eestikeelne õppevahend firma Vernier helivaljuse mõõtja kasutamiseks koos NXT komplektiga, mida õpetajad ja õpilased saavad kasutada füüsika tundides või robootika ringides. Töö loomisel jälgiti struktuuri, mida kasutatakse sarnaste tööde puhul. Töö koosneb kolmest peatükist. Esimeses andi ülevaade heli omadustele, toodi välja olulisemaid mõisteid. Teises peatükis tutvustati Vernier’i helivaljuse mõõtjat, tema omadusi ja kasutamisvõimalusi. Lisaks tehti sissejuhatust NXT-G programmeerimiskeskkonda - tutvustati olulisemaid funktsioone selleks, et kolmanda peatükki ülesandeid oleks lihtsam lahendada. Kolmanda peatükki ülesannetele on erineva raskusastmega, mis on mõeldud NXT komplekti ja anduriga tutvumiseks. Iga ülesanne loomisel kasutati ühtset malli:
• Ülesanne tase
• Ülesanne eesmärk
• Ülesanne lahendamiseks olulised vahendid
• Ülesanne püstitus
• Võimalik lahendus
• Võimalikud probleemid.
Õppematerjali loomisel arvestati sellega, et nii õpetajal kui ka õpilasel võib täielikult puududa programmeerimisoskused, seega iga funktsiooni ja ka ülesanne lahendust üritati põhjalikult ära seletada.
Antud materjali põhjal võib koostada uusi ja raskemaid ülesandeid, mida võib luua antud töös kirjeldatud ülesannete kombineerimisel.The aim of this bachelor thesis is to create a comprehensive user manual about the Vernier sound level meter in Estonian and to introduce various possibilities to use the sound sensor with LEGO Mindstorms NXT kit. This thesis consists of three chapters: the first chapter provides a brief overview of the concept of the sound and other related definitions. The in the second chapter we focus on the Verniers sound level meter and compare the sound level meter to the basic NXT sound sensor. Author also describes how to connect the sensor with LEGO Mindstorms NXT set and use it in the NXT-G programming environment. The third chapter consists of five practical exercises for the sound level meter and the NXT set. There is a two simple exercises to introduce NXT-G programming environment and three for collecting and analyze sound level meter output data. Every exercise is accompanied with a set of instructions, a list of requirements, a possible solution and a list of possible problems. All solutions are available on the CD which is attached to this document. This bachelor thesis has a similar structure to other theses from the same field and can be used as a teaching material in Estonian schools. In this thesis, we consider that both teachers and students may lack programming skills, so each function and solution has a detailed explanation. This work aims to make learning natural sciences more fun
A Jitter Measurement Circuit Based On Dual Resolution Vernier Oscillator
No full textThis paper presents a new on-chip jitter measurement circuit based on a dual vernier oscillator (VO) structure. The new structure measures the jitter with a low resolution VO first and then with a high resolution VO, thus greatly expanding the measurement range of the jitter and reducing the test time. The oscillators are implemented with differential digital controlled delay elements, whose oscillation periods can be precisely controlled The circuit has been implemented and verified with the SMIC 0.18 mu m technology and has been shown to have the ability of measuring jitters in the pico-second range.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000275924100303&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Engineering, Electrical & ElectronicEICPCI-S(ISTP)
LEGO Mindstorms NXT compatible with Vernier Hand-Grip Heart Rate Monitor
No full textAntud bakalaureuse töö eesmärgiks oli luua õppematerjalid Vernier’ südametöö monitori kasutamiseks koolides. Enne konkreetsete ülesannete valmimist tuli aru saada südame ehitusest ja ülesannetest. Lisaks südame omadustele tuli põhjalikult uurida Vernier’ südametöö monitori ja selle kasutamist LEGO Mindstorms NXT graafilises programmeerimiskeskkonnas. Veel tuli käsitleda kahte probleemi, mis tekkisid teises peatükis seoses anduriga. Üldiselt jaguneb töö neljaks osaks.
Esimeses peatükis tutvustatakse südant. Esmalt tutvustatakse olulisi avastusi südame ajaloos. Järgnevalt seletatakse põhjalikult lahti südame ehitus ja ülesanded. Lõpetuseks räägitakse, mis probleemid kaasnevad südamega ja kuidas on sport seotud südame tööga.
Teises osas tuleb vaatluse alla Vernier’ südametöö monitor, mis aitab mõõta pulssi. Selles osas räägitakse, kuidas tuleb andurit kasutada. Lisaks on vaja teada mõningaid tingimusi, et anduri kasutamine kulgeks probleemideta. Lisaks anduri põhjalikule ülevaatele saab ka teada, kuidas konkreetset andurit kasutada LEGO Mindstorms NXT-G keskkonnas.
Kolmas osa koosneb kahest osast. Esmalt käsitletakse diskreetimissagedust ja sellega seonduvaid probleeme. Kolmanda osa teises pooles uuritakse andmesalvestusrežiimi, mis aitab paremini mõista Vernier’ südametöö monitori.
Neljas osa koosneb erinevat tüüpi ülesannetest. Ülesanded on järjestatud raskusastme järgi. Ülesannete osa on kasulik sellepärast, et siis saab õpilane omandatud teadmisi praktiliselt rakendada. Korralikult ülesandeid lahendades ja soovitusi jälgides jõutakse õige lõppresultaadini. Iga ülesande puhul on ära märgitud, mis võib valesti minna. pärast ülesannete lahendamist peaks õpilane olema suuteline mõistma anduri tööpõhimõtet ja suutma kasutada toorväärtust LEGO Mindstorms NXT graafilises programmeerimiskeskkonnas.
Kokkuvõtvalt saab öelda, et kvaliteetse õppematerjali loomine on keeruline protsess. Aja kulu on meeletu ja iga peatüki puhul tuleb arvestada, kellele neid materjale luuakse. Sihtgrupile peab õppematerjal olema üheselt mõistetav. Kohati on raske jälgida seda, mida peaks lahti seletama ja mis on iseenesest mõistetav. Õppematerjal peab olema struktureeritud ja seega kõikide ideede teostus peab olema põhjalikult läbi mõeldud. Selle töö edasiarendusena näeks, et antud andurit võiks kasutada NXC keskkonnas ja ülesandeid juurde tekitada.The main purpose of this bachelor thesis was to great learning materials for using Vernier hand-grip heart rate monitor compatible with LEGO Mindstorms NXT in schools. It was necessary to understand main functions of heart before solving specific tasks. Also it was good to know some interesting facts about heart. In addition to heart functions we had to understand, how Vernier hand-grip heart rate monitor works and how it can be used in LEGO Mindstorms NXT graphical programming environment. While trying to work with this sensor two problems occurred. These problems were solved and sensor works. Different types of tasks were made in the last part of this thesis.
Heart is introduced in the first part. In the first section are written some interesting facts about heart through history. In the next steps are explained heart function, structure and diseases. Sport and its benefits are explained in the last section of part one.
The second part describes Vernier Hand-Grip Heart Rate Monitor. This sensor can measure pulse. Mostly this part concentrates on: how to use this sensor and which are the main problems while using Vernier hand-grip heart rate monitor. In addition to sensor, exhaustive overview is acquired how to use this sensor in LEGO Mindstorms NXT graphical environment.
Third part is divided into two sections. At first are described sampling rate and its problems. In the second section of part three we explore data logging and its issues. Data logging is introduced, because it gives complete understanding how Vernier hand-grip heart rate monitor works.
Fourth part consists various types of tasks. Tasks are ordered in increasing level of difficulty. Different types of tasks help students to practically use their acquired skills. All tasks are resolvable and different problems are mentioned, which can occur while completing tasks. After student completes all tasks, he or she should be able to understand this sensor and how does it work in LEGO Mindstorms NXT graphical environment.
In conclusion it can be said, that creating good learning material for school is difficult process. Amount of time that is spent while creating these materials is enormous and in every chapter has to be considered to whom these materials are created. In some cases it is hard to understand which definitions have to be explained (not explained). Learning material has to be structured and for that reason all ideas has to be thought-out. Further development of this bachelor thesis author sees: creating additional tasks and resolving tasks in NXC programming environment
Cobertura periodística del ecosistema medial digital chileno en redes sociales frente a la muerte de tres activistas durante conflictos socioambientales
No full textLa investigación examina el comportamiento del ecosistema mediático digital chileno en el contexto de conflictos socioambientales que resultaron en la muerte de activistas, centrándose en el enfoque y posicionamiento mediático en diversos tipos de medios de comunicación durante la cobertura de los casos de Camilo Catrillanca, Macarena Valdés y Alejandro Castro. Para lograr este objetivo, se recolectaron 16.166 publicaciones de 211 medios chilenos en las redes sociales Twitter, Instagram y Facebook, las cuales fueron sometidas a análisis utilizando LDA (Análisis de Distribución Latente). A partir de estos datos, se discute el uso de las plataformas, las características de los medios que lideran la cobertura, las perspectivas editoriales adoptadas y el enfoque de los contenidos publicados. En resumen, la investigación proporciona una visión detallada del posicionamiento y enfoque de los medios chilenos en la cobertura de muertes de activistas durante conflictos socioambientales, y además presenta una metodología que podría ser aplicada para analizar el comportamiento de los medios digitales en otros contextos similares
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