Real-time digital speech transmission over the Internet

This thesis describes a complete system for real-time digital speech communication over the Internet. A digital speech compressor is described, and a new real-time Internet protocol is designed. We focus on the mathematical representation of the system as well as its implementation providing pseudo-code routines for all components and algorithms. Our contribution stands in a combined solution to the problem that removes undesired properties, such as speech clipping and delay, that appeared in Internet real-time communication systems implemented in the past

A Machine Learning Approach to Denoising Particle Detector Observations in Nuclear Physics

With the evolution in detector technologies and electronic components used in the Nuclear Physics field, experimental setups become larger and more complex. Faster electronics enable particle accelerator experiments to run with higher beam intensity, providing more interactions per time and more particles per interaction. However, the increased beam intensities present a challenge to particle detectors because of the higher amount of noise and uncorrelated signals. Higher noise levels lead to a more challenging particle reconstruction process by increasing the number of combinatorics to analyze and background signals to eliminate. On the other hand, increasing the beam intensity can provide physics outcomes faster if combined with a highly efficient track reconstruction process. Thus, a method that provides efficient tracking under high luminosity conditions can significantly reduce the amount of time required to conduct physics experiments. In this poster, we present a machine learning (ML) approach for denoising data from particle tracking detectors to improve the track reconstruction efficiency of the CLAS12 detector at Jefferson Lab (JLab). A noise-reducing Convolutional Autoencoder was used to process data for standard experimental running conditions and showed significant improvements in track reconstruction efficiency (\u3e15%). The studies were extended to synthetically generated data emulating much higher beam intensity and showed that the ML approach outperforms conventional algorithms, providing a significant increase in track reconstruction efficiency of up to 80%. This tremendous increase in reconstruction efficiency allows experiments to run at almost three times higher luminosity, leading to significant savings in time (about three times shorter) and money. The software developed by this work is now part of the CLASS12 workflow, assisting scientists of JLab and collaborating institutions.https://digitalcommons.odu.edu/gradposters2022_sciences/1003/thumbnail.jp

The distributional consequences of rent seeking

We analyse the distributional effects of rent seeking via the financial sector in a model calibrated to US data. Rent seeking implies a misallocation of resources that increases wealth inequality among non rent seekers and for the whole economy. A deterioration in institutional quality implying more rent seeking leads to welfare losses for non rent seekers, especially for those with higher earnings and initial wealth, because they are most affected by the deterioration of the aggregate economy. On the other hand, welfare gains are larger for rent seekers with higher earnings and wealth, who have an increased resource extraction capacity

Public redistributive policies in general equilibrium: an application to Greece

We develop a general equilibrium OLG model of a small open economy to quantify the aggregate and distributional implications of a wide menu of public redistributive policies in a unified context. Inequality is driven by unequal parental conditions in financial and human capital. The model is calibrated and solved using fiscal data from Greece. Our aim is to search for public policies, targeted and non-targeted, that can reduce income inequality without damaging the macroeconomy and without worsening the public finances. Pareto-improving reforms that also reduce inequality include an increase in public education spending provided to all and an increase in the inheritance tax rate on financial wealth. At the other end, we identify reforms that may reduce inequality but make everybody worse o§. Regarding cases in between, a switch to a fully funded public pension system is good for everybody although it is the rich-born that benefit more by moving to a more efficient macroeconomy

A Stacking Ensemble Learning Model for Waste Prediction in Offset Printing

The production of quality printing products requires a highly complex and uncertain process, which leads to the unavoidable generation of printing defects. This common phenomenon has severe impacts on many levels for Offset Printing manufacturers, ranging from a direct economic loss to the environmental impact of wasted resources. Therefore, the accurate estimation of the amount of paper waste expected during each press run, will minimize the paper consumption while promoting environmentally sustainable principles. This work proposed a Machine Leaning (ML) framework for proactively predicting paper waste for each printing order. Based on a historical dataset extracted by an Offset Printing manufacturer, a two-level stacking ensemble learning model combining Support Vector Machine (SVM), Kernel Ridge Regression (KRR) and Extreme Gradient Boosting (XGBoost) as base learners, and Elastic Net as a meta-learner, was trained and evaluated using cross-validation. The evaluation outcomes demonstrated the ability of the proposed framework to accurately estimate the amount of waste expected to be generated for each printing run, by significantly outperforming the rest of the benchmarking models

Adaptive Physics-Based Non-Rigid Registration for Immersive Image-Guided Neuronavigation Systems

Objective: In image-guided neurosurgery, co-registered preoperative anatomical, functional, and diffusion tensor imaging can be used to facilitate a safe resection of brain tumors in eloquent areas of the brain. However, the brain deforms during surgery, particularly in the presence of tumor resection. Non-Rigid Registration (NRR) of the preoperative image data can be used to create a registered image that captures the deformation in the intraoperative image while maintaining the quality of the preoperative image. Using clinical data, this paper reports the results of a comparison of the accuracy and performance among several non-rigid registration methods for handling brain deformation. A new adaptive method that automatically removes mesh elements in the area of the resected tumor, thereby handling deformation in the presence of resection is presented. To improve the user experience, we also present a new way of using mixed reality with ultrasound, MRI, and CT. Materials and methods: This study focuses on 30 glioma surgeries performed at two different hospitals, many of which involved the resection of significant tumor volumes. An Adaptive Physics-Based Non-Rigid Registration method (A-PBNRR) registers preoperative and intraoperative MRI for each patient. The results are compared with three other readily available registration methods: a rigid registration implemented in 3D Slicer v4.4.0; a B-Spline non-rigid registration implemented in 3D Slicer v4.4.0; and PBNRR implemented in ITKv4.7.0, upon which A-PBNRR was based. Three measures were employed to facilitate a comprehensive evaluation of the registration accuracy: (i) visual assessment, (ii) a Hausdorff Distance-based metric, and (iii) a landmark-based approach using anatomical points identified by a neurosurgeon. Results: The A-PBNRR using multi-tissue mesh adaptation improved the accuracy of deformable registration by more than five times compared to rigid and traditional physics based non-rigid registration, and four times compared to B-Spline interpolation methods which are part of ITK and 3D Slicer. Performance analysis showed that A-PBNRR could be applied, on average, in \u3c2 min, achieving desirable speed for use in a clinical setting. Conclusions: The A-PBNRR method performed significantly better than other readily available registration methods at modeling deformation in the presence of resection. Both the registration accuracy and performance proved sufficient to be of clinical value in the operating room. A-PBNRR, coupled with the mixed reality system, presents a powerful and affordable solution compared to current neuronavigation systems

Advancing Intra-operative Precision: Dynamic Data-Driven Non-Rigid Registration for Enhanced Brain Tumor Resection in Image-Guided Neurosurgery

During neurosurgery, medical images of the brain are used to locate tumors and critical structures, but brain tissue shifts make pre-operative images unreliable for accurate removal of tumors. Intra-operative imaging can track these deformations but is not a substitute for pre-operative data. To address this, we use Dynamic Data-Driven Non-Rigid Registration (NRR), a complex and time-consuming image processing operation that adjusts the pre-operative image data to account for intra-operative brain shift. Our review explores a specific NRR method for registering brain MRI during image-guided neurosurgery and examines various strategies for improving the accuracy and speed of the NRR method. We demonstrate that our implementation enables NRR results to be delivered within clinical time constraints while leveraging Distributed Computing and Machine Learning to enhance registration accuracy by identifying optimal parameters for the NRR method. Additionally, we highlight challenges associated with its use in the operating room

A Fractionated Space Weather Base at L_5 using CubeSats and Solar Sails

The Sun–Earth L_5 Lagrange point is an ideal location for an operational space weather forecasting mission to provide early warning of Earth-directed solar storms (coronal mass ejections, shocks and associated solar energetic particles). Such storms can cause damage to power grids, spacecraft, communications systems and astronauts, but these effects can be mitigated if early warning is received. Space weather missions at L5 have been proposed using conventional spacecraft and chemical propulsion at costs of hundreds of millions of dollars. Here we describe a mission concept that could accomplish many of the goals at a much lower cost by dividing the payload among a cluster of interplanetary CubeSats that reach orbits around L5 using solar sails

An artificial intelligence-based collaboration approach in industrial IoT manufacturing : key concepts, architectural extensions and potential applications

The digitization of manufacturing industry has led to leaner and more efficient production, under the Industry 4.0 concept. Nowadays, datasets collected from shop floor assets and information technology (IT) systems are used in data-driven analytics efforts to support more informed business intelligence decisions. However, these results are currently only used in isolated and dispersed parts of the production process. At the same time, full integration of artificial intelligence (AI) in all parts of manufacturing systems is currently lacking. In this context, the goal of this manuscript is to present a more holistic integration of AI by promoting collaboration. To this end, collaboration is understood as a multi-dimensional conceptual term that covers all important enablers for AI adoption in manufacturing contexts and is promoted in terms of business intelligence optimization, human-in-the-loop and secure federation across manufacturing sites. To address these challenges, the proposed architectural approach builds on three technical pillars: (1) components that extend the functionality of the existing layers in the Reference Architectural Model for Industry 4.0; (2) definition of new layers for collaboration by means of human-in-the-loop and federation; (3) security concerns with AI-powered mechanisms. In addition, system implementation aspects are discussed and potential applications in industrial environments, as well as business impacts, are presented