Trigger and readout electronics for the STEREO experiment

The STEREO experiment will search for a sterile neutrino by measuring the anti-neutrino energy spectrum as a function of the distance from the source, the ILL nuclear reactor. A dedicated electronic system, hosted in a single microTCA crate, was designed for this experiment. It performs triggering in two stages with various selectable conditions, processing and readout via UDP/IPBUS of 68 photomultiplier signals continuously digitized at 250 MSPS. Additionally, for detector performance monitoring, the electronics allow on-line calibration by driving LED synchronously with the data acquisition. This paper describes the electronics requirements, architecture and the performances achieved.Comment: Topical Workshop on Electronics for Particle Physics (TWEPP) 2015, Lisboa. 9 pages, 9 figure

A design of soft-gauge for elevator vibration analysis based on low-cost accelerometer MMA7361L and LabVIEW

This paper presents a design of soft-gauge using the low-cost triple-axis accelerometer MMA7361L and LabVIEW software for the purpose of elevator vibration analysis with accuracy according to national standards. The 3-dimensional vibration signals measured and collected respectively by MMA7361L and NI USB6009 are fed into a soft-gauge programmed on LabVIEW to filter, then the fast Fourier transform (FFT) is applied to determine the power spectral density (PSD) and spectrogram of vibrations of filtered vibration signals. The soft-gauge also allows real-time 3-dimensional vibration data to be recorded, this data is used for analyzing later by another professional data software. Practical test results applied for the elevator of the DONGA Plaza building show quite good vibration analysis. Class 1.5 accuracy of the soft-gauge can be obtained by experimental test. This is a fairly cost-effective and inexpensive application that can be made in conditions with limited funds that cannot afford expensive accelerometers in the training of vibration measurement and analysis in high schools and vocational schools in developing countries, like Vietnam

Impact of spatial aliasing on sea-ice thickness measurements

We explore spatial aliasing of non-Gaussian distributions of sea-ice thickness. Using a heuristic model and \u3e1000 measurements, we show how different instrument footprint sizes and shapes can cluster thickness distributions into artificial modes, thereby distorting frequency distribution, making it difficult to compare and communicate information across spatial scales. This problem has not been dealt with systematically in sea ice until now, largely because it appears to incur no significant change in integrated thickness which often serves as a volume proxy. Concomitantly, demands are increasing for thickness distribution as a resource for modeling, monitoring and forecasting air–sea fluxes and growing human infrastructure needs in a changing polar environment. New demands include the characterization of uncertainties both regionally and seasonally for spaceborne, airborne, in situ and underwater measurements. To serve these growing needs, we quantify the impact of spatial aliasing by computing resolution error (Er) over a range of horizontal scales (x) from 5 to 500 m. Results are summarized through a power law (Er = bxm) with distinct exponents (m) from 0.3 to 0.5 using example mathematical functions including Gaussian, inverse linear and running mean filters. Recommendations and visualizations are provided to encourage discussion, new data acquisitions, analysis methods and metadata formats

Impact of spatial aliasing on sea-ice thickness measurements

We explore spatial aliasing of non-Gaussian distributions of sea-ice thickness. Using a heuristic model and \u3e1000 measurements, we show how different instrument footprint sizes and shapes can cluster thickness distributions into artificial modes, thereby distorting frequency distribution, making it difficult to compare and communicate information across spatial scales. This problem has not been dealt with systematically in sea ice until now, largely because it appears to incur no significant change in integrated thickness which often serves as a volume proxy. Concomitantly, demands are increasing for thickness distribution as a resource for modeling, monitoring and forecasting air–sea fluxes and growing human infrastructure needs in a changing polar environment. New demands include the characterization of uncertainties both regionally and seasonally for spaceborne, airborne, in situ and underwater measurements. To serve these growing needs, we quantify the impact of spatial aliasing by computing resolution error (Er) over a range of horizontal scales (x) from 5 to 500 m. Results are summarized through a power law (Er = bxm) with distinct exponents (m) from 0.3 to 0.5 using example mathematical functions including Gaussian, inverse linear and running mean filters. Recommendations and visualizations are provided to encourage discussion, new data acquisitions, analysis methods and metadata formats

TexFusion: Synthesizing 3D Textures with Text-Guided Image Diffusion Models

We present TexFusion (Texture Diffusion), a new method to synthesize textures for given 3D geometries, using large-scale text-guided image diffusion models. In contrast to recent works that leverage 2D text-to-image diffusion models to distill 3D objects using a slow and fragile optimization process, TexFusion introduces a new 3D-consistent generation technique specifically designed for texture synthesis that employs regular diffusion model sampling on different 2D rendered views. Specifically, we leverage latent diffusion models, apply the diffusion model's denoiser on a set of 2D renders of the 3D object, and aggregate the different denoising predictions on a shared latent texture map. Final output RGB textures are produced by optimizing an intermediate neural color field on the decodings of 2D renders of the latent texture. We thoroughly validate TexFusion and show that we can efficiently generate diverse, high quality and globally coherent textures. We achieve state-of-the-art text-guided texture synthesis performance using only image diffusion models, while avoiding the pitfalls of previous distillation-based methods. The text-conditioning offers detailed control and we also do not rely on any ground truth 3D textures for training. This makes our method versatile and applicable to a broad range of geometry and texture types. We hope that TexFusion will advance AI-based texturing of 3D assets for applications in virtual reality, game design, simulation, and more.Comment: Videos and more results on https://research.nvidia.com/labs/toronto-ai/texfusion

Komparatiivinen arviointi kiiltävien pintojen valaistustuloksista mallintilan valaistuksen ja ruuduntilan valaistuksen välillä

The field of computer graphics places a premium on obtaining an optimal balance between the fidelity of visual of representation and the performance of rendering. The level of fidelity for traditional shading techniques that operate in screen-space is generally related to the screen resolution and thus the number of pixels that we render. Special application areas, such as stereo rendering for virtual reality head-mounted displays, demand high output update rates and screen pixel resolutions which can then lead to significant performance penalties. This means that it would be beneficial to utilize a rendering technique which could be decoupled from the output update rate and resolution, without too severely affecting the achieved rendering quality. One technique capable of meeting this goal is that of performing a 3D model's surface shading in an object-specific space. In this thesis we have implemented such a shading method, with the lighting computations over a model's surface being done on a model-specific, uniquely parameterized texture map we call a light map. As the shading is computed per light map texel, the costs do not depend on the output resolution or update rate. Additionally, we utilize the texture sampling hardware built into the Graphics Processing Units ubiquitous in modern computing systems to gain high quality anti-aliasing on the shading results. The end result is a surface appearance that is expected to theoretically be close to those resulting from highly supersampled screen-space shading techniques. In addition to the object-space lighting technique, we also implemented a traditional screen-space version of our shading algorithm. Both of these techniques were used in a user study we organized to test against the theoretical expectation. The results from the study indicated that the object-space shaded images are perceptually close to identical compared to heavily supersampled screen-space images.Tietokonegrafiikan alalla optimaalisen tasapainon saavuttaminen kuvanlaadun ja laskentanopeuden välillä on keskeisessä asemassa. Perinteisillä, kuvaruuduntilassa toimivilla valaistusalgoritmeilla kuvanlaatu on tyypillisesti riippuvainen käytetyn piirtoikkunan erottelutarkkuudesta ja näin ollen kuvaelementtien kokonaismäärästä. Tietyt sovellusalueet, kuten stereopiirtäminen keinotodellisuussovelluksille, edellyttävät korkeata ruudunpäivitystaajuutta sekä erottelutarkkuutta, mikä taas johtaa laskentatehovaatimusten kasvuun. Näin ollen on tarkoituksenmukaista hyödyntää algoritmeja, joissa valaistuslaskenta saataisiin erotettua näistä ominaisuuksista ilman merkittävää kuvanlaadun heikkenemistä. Yksi algoritmikategoria, joka täyttää nämä asetetut vaatimukset on valaistuslaskenta 3D-mallikohtaisessa tilassa. Tämän diplomityön puitteissa olemme toteuttaneet tähän kategoriaan lukeutuvan valaistusalgoritmin, jossa valaistuslaskenta suoritetaan mallikohtaisella, yksikäsitteisesti parametrisoidulla tekstuurikartalla. Tämä tarkoittaa, että valaistuslaskennasta koituvat suorituskykykustannukset eivät ole riippuvaisia aiemmin mainituista ruudun ominaisuuksista. Valaistuslaskenta yksilöllisiin tekstuurikarttoihin mahdollistaa näytönohjaimiin sisäänrakennetun teksturointilaitteiston käyttämisen korkealaatuiseen valaistustulosten suodattamiseen. Lopputuloksena saavutetaan piirretty kuva, jonka teoreettisesti oletetaan olevan laadultaan lähellä merkittävästi ylinäytteistettyä ruuduntilan valaistusalgoritmeille saavutettuja tuloksia. Mallikohtaisen tilan valaistusalgoritmin lisäksi toteutimme perinteisen ruuduntilan valaistusalgoritmiversion. Molempia toteutuksia käytettiin järjestämässämme käyttäjätestissä, jonka tavoitteena oli testata toteutuuko mainittu teoreettinen oletus käytännössä. Käyttäjätestin tulokset viittasivat vahvasti oletuksen pätevyyteen, käyttäjien kokonaisvaltaisesti kokien ylinäytteistetyn perinteisen valaistuslaskennan tulokset lähes identtisiksi mallintilan valaistuslaskennan tuloksiin

Efficient, low-distortion switch-mode power amplifier for amplitude modulation

Thesis (M. Eng.)--Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, February 2011.Cataloged from PDF version of thesis. "September 28, 2010."Includes bibliographical references (pages 85-87).Amplitude modulation systems are used in many areas of engineering, especially communication based disciplines. Typical systems have low-level signals which encode the desired information to be transmitted. These low-level signals are usually not of adequate power to transmit the desired information across a target medium, thus requiring modulation and power amplification. In general, two goals of power amplifier design are low-distortion and high-efficiency. To meet these goals, a unique switch-mode power amplifier intended for amplitude modulation which utilizes spectral content at the carrier frequency is designed, simulated, and built. Theoretical predictions of total harmonic distortion (THD) and efficiency are made, and the constructed prototype results are measured. The THD for a 1 kHz modulating tone is predicted to be 0.9% and measured to be 4.15% worst case. The amplifier output stage efficiency is predicted to be 95.8% and measured to be 95.4% worst case.by Christopher Buenrostro.M.Eng

Project LAB

Treball desenvolupat dins el marc del programa 'European Project Semester'.In the North Sea, the construction of wind parks using pile driving forms a threat to porpoises, since they have a very sensitive auditory system. In order to protect this species, the construction work has to be stopped when they are nearby. The purpose of this project is to design a low-cost buoy which should be able to detect these animals in their natural environment and subsequently serve as a supportive device for offshore workers. Additionally, a proposal for a tracking device which can be directly attached to the animals was made. To achieve these objectives, research was conducted on requirements for buoys in North Sea conditions, the behaviour of porpoises, and technical components as well as the necessary software for detection. This report proposes a design for a buoy to meet these objectives

Nat Methods

High-speed, large-scale three-dimensional (3D) imaging of neuronal activity poses a major challenge in neuroscience. Here we demonstrate simultaneous functional imaging of neuronal activity at single-neuron resolution in an entire Caenorhabditis elegans and in larval zebrafish brain. Our technique captures the dynamics of spiking neurons in volumes of \ue2\u2c6\ubc700 \uce\ubcm \uc3\u2014 700 \uce\ubcm \uc3\u2014 200 \uce\ubcm at 20 Hz. Its simplicity makes it an attractive tool for high-speed volumetric calcium imaging.1DP1NS087724/DP/NCCDPHP CDC HHS/United States1R01EY023173/EY/NEI NIH HHS/United StatesDP1 NS087724/NS/NINDS NIH HHS/United StatesR01 EY023173/EY/NEI NIH HHS/United States2015-01-01T00:00:00Z24836920PMC410025