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关键词： Artificial intelligence   Computer science   Information technology  

关键词： Computer science   Neurosciences   Biomedical engineering  

摘要： With billions of neurons and trillions of synapses in humans, the inner workings of the brain remain one of the great open mysteries of the universe. A complete understanding of the brains of even tiny organisms such as Caenorhabditis elegans remains elusive. The field of connectomics seeks to unravel the mysteries of brains by analyzing their circuitry at a synaptic level. In pursuit of this goal, neuroscientists extract and image brain tissue from various species, trace the neurons through the images, identify all synaptic connections, and construct a wiring diagram. A team of researchers spent a dozen years manually extracting the first nearly complete connectome from an image stack. This early success contained 302 neurons and 5,000 synapses. In the succeeding decades, automated algorithms have complemented and, at times, replaced manual human reconstruction efforts. More recently produced wiring diagrams, or connectomes, contain thousands of neurons with millions of synaptic connections. Recent advancements in image acquisition using multi-beam electron microscopes enable neuroscientists to capture one terabyte of raw image data every hour. Although these engineering achievements open the door for imaging larger brain volumes from more evolved species, human labor, particularly that which requires expert knowledge, has become the bottleneck. Therefore, researchers have increasingly relied on automated solutions to reconstruct neurons from the raw image data and extract the wiring diagrams. The previous decade has seen a deluge of new algorithms that confront the challenges of converting the raw image data into connectomes for further analysis. Despite the incredible success of these algorithms, there is still room for improvement in accuracy and efficiency. By guiding algorithm design with existing biological knowledge, we can improve accuracy, reduce complexity, and generate results more faithful to the neuronal data. We demonstrate these principles with four

关键词： Computer science  

摘要： From the early days of the mid to late nineteenth century when scientific research first began to focus on fingerprints, to the present day fingerprint recognition systems we find deployed on our day to day devices, the science of fingerprint recognition has come a long way. In spite of this progress, there remains challenging problems to be solved. This thesis highlights a few of these problems, and proposes solutions to address them. One area of further research that must be conducted on fingerprint recognition systems is that of robust, operational evaluations. In chapter two of this thesis, we show how the current practices of using calibration patterns to evaluate fingerprint readers are limited. We then propose a realistic fake finger called the Universal Target. The Universal Target is a realistic, 3D, fake finger (or phantom) which can be imaged by all major types of fingerprint sensing technologies. We show the entire manufacturing (molding and casting) process for fabricating the Universal Targets. Then, we show a series of evaluations which demonstrate how the Universal Targets can be used to operationally evaluate current commercial fingerprint readers. Our Universal Target is a significant step forward in enabling more realistic, standardized evaluations of fingerprint readers. In our third chapter, we shift gears from improving the evaluation standards of fingerprint readers to instead focus on the security of fingerprint readers. In particular, we turn our attention towards detecting fake fingerprint (spoof) attacks. To do so, we open source a fingerprint reader (built from low-cost ubiquitous components), called RaspiReader. RaspiReader is a high-resolution fingerprint reader customized with both direct-view imaging and FTIR imaging in order to better detect fingerprint spoofs. We show through a number of experiments that RaspiReader enables state-of-the-art fingerprint spoof detection accuracy. We also demonstrate that RaspiReader enables better gen

关键词： Global positioning systems--GPS   Statistical data   Autonomous vehicles   Roads & highways   Causality   Algorithms   Decision trees   Traffic congestion   Computer science   Transportation  

摘要： Autonomous Vehicles (AVs) can dramatically reduce the number of traffic crashes and associated fatalities by eliminating the avoidable human-errors related crash contributing factors. Many companies have been conducting pilot tests on public roads in several states in the United States and other countries to accelerate AV mass deployment. AV pilot operations on California public roads saw 251 AV-involved crashes (as of February 2020). These AV-involved crashes provide a unique opportunity to investigate AV crash risks in a mixed traffic environment. This study collected the AV crash reports from the California Department of Motor Vehicles and applied the Decision Tree (DT), and Association Rule methods to extract the pre-crash rules of AV-involved crashes. Extracted rules revealed that the most frequent types of AV crashes were rear-end crashes and predominantly occurred at intersections when AVs were stopped and engaged in the autonomous mode. AV and Non-AV manufacturers, and transportation agencies can use the findings of this study to minimize AV-related crashes. AV companies could install a distinct signal/display to inform the operational mode of the AVs (i.e., autonomous or non-autonomous) to human drivers around them. Moreover, the Automatic Emergency Braking system in non-AVs could avoid a significant number of rear-end crashes as often rear-end crashes occurred due to the failure of following non-AVs timely slow down behind AVs. Transportation agencies can consider separating the AVs from the non-AVs by assigning “AV only lanes” to eliminate the excessive rear-end crashes due to the mistakes of human drivers in non-AVs at the intersections.

关键词： Computer science   Optics   Computational physics  

摘要： Physically-based rendering has become mature and commonplace in recent decades. However, the rendered results look artificial and overly perfect. Better realism needs higher fidelity detailed geometry or model complexity, which substantially increases computational power and human works. To achieve higher physical realism and enable more effective material content creation, many techniques are developed in material reflection and scattering models. We put emphasis on accurately representing and reproducing the rich visual world from micro-level scales. The first half of the dissertation focuses on building the bridge from micro-model to macro properties: we present an accurate appearance model for layered materials derived from microstructures to define their optical behavior and a general framework of bulk scattering in participating medium which considers the microscale effects. Consequently, in the second half, we discuss the inverse problem of retrieving the micro parameters from captured materials.

关键词： Fines & penalties   Population genetics   Co authorship   Algorithms   Neighborhoods   Artificial intelligence   Computer science   Genetics  

摘要： We consider the vector embedding problem. We are given a finite set of items, with the goal of assigning a representative vector to each one, possibly under some constraints (such as the collection of vectors being standardized, i.e., having zero mean and unit covariance). We are given data indicating that some pairs of items are similar, and optionally, some other pairs are dissimilar. For pairs of similar items, we want the corresponding vectors to be near each other, and for dissimilar pairs, we want the corresponding vectors to not be near each other, measured in Euclidean distance. We formalize this by introducing distortion functions, defined for some pairs of the items. Our goal is to choose an embedding that minimizes the total distortion, subject to the constraints. We call this the minimum-distortion embedding (MDE) problem. This monograph is accompanied by an open-source Python package, PyMDE, for approximately solving MDE problems. Users can select from a library of distortion functions and constraints or specify custom ones, making it easy to rapidly experiment with different embeddings. Because our algorithm is scalable, and because PyMDE can exploit GPUs, our software scales to data sets with millions of items and tens of millions of distortion functions. Additionally, PyMDE is competitive in runtime with specialized implementations of specific embedding methods. To demonstrate our method, we compute embeddings for several real-world data sets, including images, an academic co-author network, US county demographic data, and single-cell mRNA transcriptomes.

关键词： Electrical engineering   Computer engineering   Computer science   Transportation   Robotics  

摘要： The increased penetration of Electric Vehicle (EV) will provide substantial benefits to the environment. However, each EV will present a significant additional load to electric power distribution infrastructure, especially to radial distribution feeders. The additional load may cause transformers to operate beyond their thermal limits, unacceptable voltage drops along distribution lines, and primary conductor overloads. It is now, more than ever, vital to understand the limitations of existing infrastructure in light of an accelerating push for greener alternatives with insight that stems from modeling, simulation, and proper analysis as the backbone to a well-informed response. The objective of this work is to develop EV load growth modeling and analysis tools for distribution systems. These tools will help researchers and distribution engineers better understand the impacts EV growth will have on distribution systems. Such studies can help a utility company take appropriate action to enhance grid stability and reliability. In the following pages, three analysis tools for evaluating impacts of EV on grid infrastructure assets are presented. These tools are developed for use in the GridLAB-D modeling environment and written using Python 3.8. The analysis tools were developed to serve unique purposes. The first tool notifies a user of voltage violations. The second tool identifies conductor overloads. The third tool alerts the user of transformer overloads. These tools have been evaluated using the IEEE 13 node test feeder coupled with typical household load profiles within GridLAB-D. Using these tools, users evaluate the impacts EV loads have on distribution systems, specifically transformer overloading, voltage violations, and the overload of conductors. These tools can help utility distribution planners prepare appropriate response for anticipated EV load growth.

关键词： Gene expression   Boolean   Cytotoxicity   Algorithms   Decision trees   Cell cycle   Bioinformatics   Cellular biology   Computer science   Genetics  

关键词： Operations research   Health care management   Computer science  

摘要： Markov Decision Processes (MDP) is a common framework for modeling sequential decision-making problems, with applications ranging from inventory and supply chains to healthcare applications, autonomous driving and solving repeated games. Despite its modeling power, two fundamental challenges arise when using the MDP framework in real-world applications. First, the optimal decision rule may be highly dependent on the MDP parameters (e.g., transition rates across states and rewards for each state-action pair). When the parameters are miss-estimated, the resulting decision rule may be suboptimal when deployed in practice. Additionally, the optimal policies computed by state-of-the-art algorithms may not be interpretable and can be seen as a black-box. Among other reasons, this is problematic as the policy may not be understandable for the people that are supposed to operationalize it. In this thesis, we aim to broaden the applicability of the MDP framework by addressing the challenges of robustness and interpretability. In the first part of the thesis, we focus on robustness. We introduce a novel model for parameter uncertainty in Chapter 2, that is significantly less pessimistic than prior models of uncertainty while enabling the efficient computation of a robust policy. In Chapter 3, we consider a healthcare application, where we focus on proactively transferring patients of a hospital to the Intensive Care Unit, to ameliorate the overall survival rates and patients’ flow. In the second part of this thesis, we focus on interpretable algorithms, with an emphasis on the application to find novel triage protocols for ventilator allocations for COVID-19 patients. In Chapter 4, we introduce a simulation model to estimate the performance of the official New York State (NYS) triage protocol at various levels of shortages of ventilators, using a real data set of patients intubated during Spring 2020 because of COVID-19 complications. In Chapter 5, we introduce our algorithmi

关键词： Theater   Computer science   Artificial intelligence   Judaism   Scripts   Stage direction   Writing   Dialogue   Design   Actors   Emotions   20th century   Animation   Jewish culture   Games   Aesthetics   Jews   Ghosts  

摘要： The game making up this thesis, Tracks in Snow, and by extension the underlying technology of Puppitor, began with a simple premise: what if instead of players choosing what they wanted to say they instead were mainly focused on how they were saying it? This approach has been heavily inspired by the work on theater productions, particularly when production started, seeing the actors and directors take the words I’d written in quite different directions than what I’d had initially envisioned. Also let’s face it, we call a play a play. Why not try to make the playing of a play the basis for digital character interaction? After all, it’s been working for humans for several thousand years. To reach these ends I built a computational caricature of theatrical acting practices, including Stanislavsky’s Method, Anne Bogart and Tina Landau’s Viewpoints, and Zeami’s Treatises on Noh drama as a way to shift players away from controlling the structure of a narrative and towards control over the details. Tracks in Snow is built in Ren’Py to wrap this novel interaction style in a more familiar format. The game’s story focuses on one character’s crisis of faith and another’s longing for a home that only really exists in the past. My hope is that the interface I have created gets players to focus more on role-playing characters than trying to optimize their responses.