9 research outputs found
Constructive synthesis of optimized cryptographic primitives
No full textThesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2017.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 63-65).In this thesis, I designed and implemented a formally verified compiler for programs over arbitrary-width integers in Parametric Higher-Order Abstract Syntax. This was part of a larger project, Fiat-crypto, which seeks to produce formally verified machine-code implementations of Elliptic Curve Cryptography. My implementation outputs Qhasm, a high-level assembly language developed for the implementation of highly optimised cryptography, and maintains platform independence by being totally parametric over the width of system words.by Robert M. Sloan, Jr.M. Eng
Long wave infrared structured light
No full textThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2019Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 69-72).3D sensing technologies have been exploited for many applications in autonomous vehicles, manufacturing, and consumer products, however, existing techniques may suer in challenging conditions, where scattering due to fog, dust, or smoke is present. While light in the visible and near IR spectrum are heavily affected by by common scattering mediums, long-wave infrared (also known as thermal IR) experiences less scattering, especially when scattering particles are small. This thesis proposes and demonstrates a structured light scanning approach which operates in the long-wave IR Spectrum. We believe that structured light technique with long-wave IR leads to more robust 3D sensing in some challenging environments. In this thesis the conceptual framework behind the technology is presented, the technology is demonstrated, and testing of long-wave infrared projection is compared to the visible spectrum.by Jack Erdozain Jr.M. Eng.M.Eng. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Scienc
Cohort selection and sampling techniques to balance time-series retrospective studies
No full textThesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2017.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 85-86).Comparing irregular and event-driven time series data points is beyond the capabilities of most statistical techniques. This limits the potential to run insightful retrospective studies on many cross-sectional time-series datasets. In order to unlock the value of these datasets, we need techniques to standardize observations with irregular events enough to compare them to each other, and ways to select and sample them so as to produce class balances for each strata at modeling time that lend themselves to statistically sound analysis. In this study, we have developed two selection techniques and three sampling techniques for a characteristic cross-sectional time-series dataset. We found that using a Fluid-Balance Similarity-Based Dynamic Time Warp selection procedure with nearest neighbor parameter k=1 and using a Gamma distribution for sampling days produced consistently better class balance than all other methods when bootstrapped over 100 independent runs. We have written, documented and published open source MATLAB code for each selection and sampling technique, along with our bootstrap test. To evaluate our results, we have developed the Class Imbalance Penalty, a new metric that gives the lowest scores to the selection and sampling runs that produce most comparable counts of treatment and non-treatment observations for all strata. We validated our methods in the context of a study of diuretics treatment effects in ICU patients with Sepsis, drawn from the MIMIC II database. Starting from a group of 3,503 unique ICU stays from 2,341 study patients, with a Diuretics-treatment cohort of 349 unique ICU stays from 332 patients, we tested each selection and sampling technique, observing the trends across our dierent methods. We observed that sampling day was the stronger predictor of good class balance compared with selection technique, that the strongest similarity level (k=1) with the shortest history we considered produced the best results, and using a Gamma distribution for timepoint sampling most closely matched the distribution of actual administration days. Ultimately, we found strong evidence that our study lacked an important co- variate, physician-id, to more fully account for seemingly unpredictable assignments to Diuretics-treatment in our dataset.by Brian Bell Jr.M. Eng
Modal Analysis Of Valve Train Test Rig Support Structure
No full textImprovement of fuel economy is one of the most important development targets of modern passenger car engines. Modern solutions such as Direct Injection, Variable Valve Trains, or Cylinder Deactivation help to obtain this requirement. Each one of these techniques optimize the thermodynamic efficiency of the engine. However, the mechanical structure of combustion engines shows many areas of possible optimization regarding the mechanical efficiency. Engine friction affects the overall fuel consumption, mainly under low speed conditions combined with part load. Low speed/part load conditions are relevant for the real life fuel consumption of an engine, as well as friction improvements have significant effects on the fuel economy. The valve train drive produces the dominant friction portion under these conditions. Hence the friction optimization of this engine subsystem is one of the key issues regarding mechanical efficiency. The valve train friction consists mainly of friction produced by the contact between cam and cam follower, e.g. tappet or finger lever. The introduction of a roller contact to the cam, is a known optimization method. However the cam shaft bearings need to be optimized as well. This paper explains the influence of the cylinder head structure on the behavior of the cam shaft bearings. The modal analysis method shows the test rig structure influence on the valve train components during vibrational analysis. Conclusions and suggestions for the system are presented. Copyright © 2001 Society of Automotive Engineers, Inc.Dedini, F.G., Cavalca, K.L., Aplicação de métodos de identificação teórico experimentais na análise de um turbogerador com sete mancais (1993) XII COBEM CONGRESSO BRASILEIRO de ENGENHARIA MECÂNICA, pp. 1241-1244. , Brasília - Brasil, DezembroCavalca, K.L., Cavalcante, P.F., Interação rotor-estrutura de fundação através de mancais hidrodinâmicos (1997) XIV COBEM CONGRESSO BRASILEIRO de ENGENHARIA MECÂNICA, , Bauru - Brasil, DezembroCavalcante, P.F., Cavalca, K.L., A method to analyse the interaction between rotor-foundation systems (1998) IMAC 98 International Modal Analysis Conference, , Santa Barbara - USA, FevereiroJainski, T., Modal resolution of transient vibrations in Rotor-Bearing-foundation systems caused by electrical system faults (1982) IFToMM - INTERNATIONAL CONFERENCE, pp. 177-189. , Rome -Italy, September 1982Weiming, L., Novak, M., Dynamic behavior of turbine-generator- foundation systems (1996) Earthquake Engineering & Structural Dynamics, 24 (3), pp. 339-360. , MayAneja, I.A., Dynamic interacting response of large turbine-generators supported on foundations of different flexibilities (1982) IFToMM - INTERNATIONAL CONFERENCE, pp. 129-138. , Rome -Italy, September, 1982Cavalca, K.L., Dedini, F.G., Experimental analysis of a tilting pad journal bearing influence in a vertical rotating system (1998) IFToMM 98, pp. 571-582. , 7-10 September, Darmstadt - AlemanhaGéradin, M., Rixen, D., (1996) Mechanical Vibration: Theory and Application to Structural Dynamics, , 2nd Edition, John Wiley & SonsCavalca, K.L., Dias, Jr.M., Dedini, F.G., Determinação das Caraterísticas Modais de Bancada para Testes de Comando de Válvulas (2001) Relatório 05/2001 - DPM/FEM/UNICAMP, , Junho(1997) Theoretical and Experimental Modal Analysis, , Maia N. M. M. Silva J. M. M. (editors), John Wiley & Sons In
Search for intermediate-mass black hole binaries in the third observing run of Advanced LIGO and Advanced Virgo
No full textInternational audienceIntermediate-mass black holes (IMBHs) span the approximate mass range 100−105 M⊙, between black holes (BHs) that formed by stellar collapse and the supermassive BHs at the centers of galaxies. Mergers of IMBH binaries are the most energetic gravitational-wave sources accessible by the terrestrial detector network. Searches of the first two observing runs of Advanced LIGO and Advanced Virgo did not yield any significant IMBH binary signals. In the third observing run (O3), the increased network sensitivity enabled the detection of GW190521, a signal consistent with a binary merger of mass ∼150 M⊙ providing direct evidence of IMBH formation. Here, we report on a dedicated search of O3 data for further IMBH binary mergers, combining both modeled (matched filter) and model-independent search methods. We find some marginal candidates, but none are sufficiently significant to indicate detection of further IMBH mergers. We quantify the sensitivity of the individual search methods and of the combined search using a suite of IMBH binary signals obtained via numerical relativity, including the effects of spins misaligned with the binary orbital axis, and present the resulting upper limits on astrophysical merger rates. Our most stringent limit is for equal mass and aligned spin BH binary of total mass 200 M⊙ and effective aligned spin 0.8 at 0.056 Gpc−3 yr−1 (90% confidence), a factor of 3.5 more constraining than previous LIGO-Virgo limits. We also update the estimated rate of mergers similar to GW190521 to 0.08 Gpc−3 yr−1.Key words: gravitational waves / stars: black holes / black hole physicsCorresponding author: W. Del Pozzo, e-mail: [email protected]† Deceased, August 2020
Probing transversity by measuring polarisation in SIDIS
No full textBased on the observation of sizeable target-transverse-spin asymmetries in single-hadron and hadron-pair production in Semi-Inclusive measurements of Deep Inelastic Scattering (SIDIS), the chiral-odd transversity quark distribution functions are nowadays well established. Several possible channels to access these functions were originally proposed. One candidate is the measurement of the polarisation of hyperons produced in SIDIS off transversely polarised nucleons, where the transverse polarisation of the struck quark might be transferred to the final-state hyperon. In this article, we present the COMPASS results on the transversity-induced polarisation of and hyperons produced in SIDIS off transversely polarised protons. Within the experimental uncertainties, no significant deviation from zero was observed. The results are discussed in the context of different models taking into account previous experimental results on and .Based on the observation of sizeable target-transverse-spin asymmetries in single-hadron and hadron-pair production in Semi-Inclusive measurements of Deep Inelastic Scattering (SIDIS), the chiral-odd transversity quark distribution functions h1q are nowadays well established. Several possible channels to access these functions were originally proposed. One candidate is the measurement of the polarisation of Λ hyperons produced in SIDIS off transversely polarised nucleons, where the transverse polarisation of the struck quark might be transferred to the final-state hyperon. In this article, we present the COMPASS results on the transversity-induced polarisation of Λ and Λ¯ hyperons produced in SIDIS off transversely polarised protons. Within the experimental uncertainties, no significant deviation from zero was observed. The results are discussed in the context of different models taking into account previous experimental results on h1u and h1d.Based on the observation of sizeable target-transverse-spin asymmetries in single-hadron and hadron-pair production in Semi-Inclusive measurements of Deep Inelastic Scattering (SIDIS), the chiral-odd transversity quark distribution functions are nowadays well established. Several possible channels to access these functions were originally proposed. One candidate is the measurement of the polarisation of hyperons produced in SIDIS off transversely polarised nucleons, where the transverse polarisation of the struck quark might be transferred to the final-state hyperon. In this article, we present the COMPASS results on the transversity-induced polarisation of and hyperons produced in SIDIS off transversely polarised protons. Within the experimental uncertainties, no significant deviation from zero was observed. The results are discussed in the context of different models taking into account previous experimental results on and
Data Quality Monitoring for the Hadron Calorimeters Using Transfer Learning for Anomaly Detection
No full textThe proliferation of sensors brings an immense volume of spatio-temporal (ST) data in many domains, including monitoring, diagnostics, and prognostics applications. Data curation is a time-consuming process for a large volume of data, making it challenging and expensive to deploy data analytics platforms in new environments. Transfer learning (TL) mechanisms promise to mitigate data sparsity and model complexity by utilizing pre-trained models for a new task. Despite the triumph of TL in fields like computer vision and natural language processing, efforts on complex ST models for anomaly detection (AD) applications are limited. In this study, we present the potential of TL within the context of high-dimensional ST AD with a hybrid autoencoder architecture, incorporating convolutional, graph, and recurrent neural networks. Motivated by the need for improved model accuracy and robustness, particularly in scenarios with limited training data on systems with thousands of sensors, this research investigates the transferability of models trained on different sections of the Hadron Calorimeter of the Compact Muon Solenoid experiment at CERN. The key contributions of the study include exploring TL's potential and limitations within the context of encoder and decoder networks, revealing insights into model initialization and training configurations that enhance performance while substantially reducing trainable parameters and mitigating data contamination effects. Code: https://github.com/muleina/CMS_HCAL_ML_OnlineDQM
Design of the ECCE detector for the Electron Ion Collider
No full textThe EIC Comprehensive Chromodynamics Experiment (ECCE) detector has been designed to address the full scope of the proposed Electron Ion Collider (EIC) physics program as presented by the National Academy of Science and provide a deeper understanding of the quark-gluon structure of matter. To accomplish this, the ECCE detector offers nearly acceptance and energy coverage along with excellent tracking and particle identification. The ECCE detector was designed to be built within the budget envelope set out by the EIC project while simultaneously managing cost and schedule risks. This detector concept has been selected to be the basis for the EIC project detector
AI-assisted Optimization of the ECCE Tracking System at the Electron Ion Collider
No full textThe Electron-Ion Collider (EIC) is a cutting-edge accelerator facility that
will study the nature of the "glue" that binds the building blocks of the
visible matter in the universe. The proposed experiment will be realized at
Brookhaven National Laboratory in approximately 10 years from now, with
detector design and R&D currently ongoing. Notably, EIC is one of the first
large-scale facilities to leverage Artificial Intelligence (AI) already
starting from the design and R&D phases. The EIC Comprehensive Chromodynamics
Experiment (ECCE) is a consortium that proposed a detector design based on a
1.5T solenoid. The EIC detector proposal review concluded that the ECCE design
will serve as the reference design for an EIC detector. Herein we describe a
comprehensive optimization of the ECCE tracker using AI. The work required a
complex parametrization of the simulated detector system. Our approach dealt
with an optimization problem in a multidimensional design space driven by
multiple objectives that encode the detector performance, while satisfying
several mechanical constraints. We describe our strategy and show results
obtained for the ECCE tracking system. The AI-assisted design is agnostic to
the simulation framework and can be extended to other sub-detectors or to a
system of sub-detectors to further optimize the performance of the EIC
detector.Comment: 16 pages, 18 figures, 2 appendices, 3 table
