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Industrial-Age Doubling Of Snow Accumulation In The Alaska Range Linked To Tropical Ocean Warming, Dominic Winski, Erich Osterberg, David Ferris, Karl Kreutz, Cameron Wake, Seth Campbell, Robert Hawley, Samuel Roy, Sean Birkel, Douglas Introne, Michael Handley
Industrial-Age Doubling Of Snow Accumulation In The Alaska Range Linked To Tropical Ocean Warming, Dominic Winski, Erich Osterberg, David Ferris, Karl Kreutz, Cameron Wake, Seth Campbell, Robert Hawley, Samuel Roy, Sean Birkel, Douglas Introne, Michael Handley
Dartmouth Scholarship
Future precipitation changes in a warming climate depend regionally upon the response of natural climate modes to anthropogenic forcing. North Pacific hydroclimate is dominated by the Aleutian Low, a semi-permanent wintertime feature characterized by frequent low-pressure conditions that is influenced by tropical Pacific Ocean temperatures through the Pacific-North American (PNA) teleconnection pattern. Instrumental records show a recent increase in coastal Alaskan precipitation and Aleutian Low intensification, but are of insufficient length to accurately assess low frequency trends and forcing mechanisms. Here we present a 1200-year seasonally- to annually-resolved ice core record of snow accumulation from Mt. Hunter in the Alaska …
Note From The Editorial Board
Dartmouth Undergraduate Journal of Science
No abstract provided.
Faculty Spotlight: Gordon Gribble, Samuel R. Reed
Faculty Spotlight: Gordon Gribble, Samuel R. Reed
Dartmouth Undergraduate Journal of Science
Professor Gordon Gribble received his B.S. from U.C. Berkeley and his Ph.D. from the University of Oregon. He has been at Dartmouth for the past 49 years, and in that time he has taught chemistry to a great number of students. His research in the field of organic chemistry features indole and triterpenoid synthesis, and has yielded a wide range of medications.
Random Walk Null Models For Time Series Data, Daryl Deford, Katherine Moore
Random Walk Null Models For Time Series Data, Daryl Deford, Katherine Moore
Dartmouth Scholarship
Permutation entropy has become a standard tool for time series analysis that exploits the temporal and ordinal relationships within data. Motivated by a Kullback–Leibler divergence interpretation of permutation entropy as divergence from white noise, we extend pattern-based methods to the setting of random walk data. We analyze random walk null models for correlated time series and describe a method for determining the corresponding ordinal pattern distributions. These null models more accurately reflect the observed pattern distributions in some economic data. This leads us to define a measure of complexity using the deviation of a time series from an associated random …
Spice: Secure Proximity-Based Infrastructure For Close Encounters, Aarathi Prasad, Xiaohui Liang, David Kotz
Spice: Secure Proximity-Based Infrastructure For Close Encounters, Aarathi Prasad, Xiaohui Liang, David Kotz
Dartmouth Scholarship
We present a crowdsourcing system that extends the capabilities of location-based applications and allows users to connect and exchange information with users in spatial and temporal proximity. We define this incident of spatio-temporal proximity as a \em close encounter. Typically, location-based application users store their information on a server, and trust the server to provide access only to authorized users, not misuse the data or disclose their location history. Our system, called SPICE, addresses these privacy issues by leveraging Wi-Fi access points to connect users and encrypt their information before it is exchanged, so only users in close encounters have …
A Statistical Prior For Photo Forensics: Object Removal, Wei Fan, Hany Farid
A Statistical Prior For Photo Forensics: Object Removal, Wei Fan, Hany Farid
Computer Science Technical Reports
If we consider photo forensics within a Bayesian framework, then the probability that an image has been manipulated given the results of a forensic test can be expressed as a product of a likelihood term (the probability of a forensic test detecting manipulation given that an image was manipulated) and a prior term (the probability that an image was manipulated). Despite the success of many forensic techniques, the incorporation of a statistical prior has not been previously considered. We describe a framework for incorporating statistical priors into any forensic analysis and specifically address the problem of quantifying the probability that …
A Digital Practice Tool For Chemical Resonance, Kimball Jaclyn
A Digital Practice Tool For Chemical Resonance, Kimball Jaclyn
Dartmouth College Master’s Theses
Digital practice tools support online learning in math, language, computer science, and other subjects, but practice with problems whose answers are not well represented by text or quantities is underrepresented in the digital learning ecosystem beyond multiple-choice questions. This thesis project explored an alternative to multiple choice practice problems in organic chemistry that does not rely on a molecule drawing interface. This project included development and evaluation of a proof-of-concept digital practice tool for chemical resonance problems. Results of a utility study strongly suggest that the practice tool could fill a learning niche within organic chemistry practice as part of …
Shareabel: Secure Sharing Of Mhealth Data Through Cryptographically-Enforced Access Control, Emily Greene
Shareabel: Secure Sharing Of Mhealth Data Through Cryptographically-Enforced Access Control, Emily Greene
Dartmouth College Undergraduate Theses
Owners of mobile-health apps and devices often want to share their mHealth data with others, such as physicians, therapists, coaches, and caregivers. For privacy reasons, however, they typically want to share a limited subset of their information with each recipient according to their preferences. In this paper, we introduce ShareABEL, a scalable, usable, and practical system that allows mHealth-data owners to specify access-control policies and to cryptographically enforce those policies so that only parties with the proper corresponding permissions are able to decrypt data. The design (and prototype implementation) of this system makes three contributions: (1) it applies cryptographically-enforced access-control …
Golden Tools In Green Design: What Drives Sustainability, Innovation, And Value In Green Design Methods?, Jeremy Faludi
Golden Tools In Green Design: What Drives Sustainability, Innovation, And Value In Green Design Methods?, Jeremy Faludi
Dartmouth Scholarship
What do product design teams value in sustainable design methods? Specifically, what kinds of activities and mindsets comprise different design methods, and which ones do design teams believe drive sustainability, innovation, and other value? How could they be combined to improve sustainable design’s value to companies? This study was the first to deconstruct green product design practices into their constituent activities and mindsets to characterize them and hypothesize their potential synergies. It was also the first to empirically test and compare what practitioners value within three of these sustainable design practices—The Natural Step, Whole System Mapping, and Biomimicry. Others have …
Toward Accurate And Efficient Feature Selection For Speaker Recognition On Wearables, Rui Liu, Reza Rawassizadeh, David Kotz
Toward Accurate And Efficient Feature Selection For Speaker Recognition On Wearables, Rui Liu, Reza Rawassizadeh, David Kotz
Dartmouth Scholarship
Due to the user-interface limitations of wearable devices, voice-based interfaces are becoming more common; speaker recognition may then address the authentication requirements of wearable applications. Wearable devices have small form factor, limited energy budget and limited computational capacity. In this paper, we examine the challenge of computing speaker recognition on small wearable platforms, and specifically, reducing resource use (energy use, response time) by trimming the input through careful feature selections. For our experiments, we analyze four different feature-selection algorithms and three different feature sets for speaker identification and speaker verification. Our results show that Principal Component Analysis (PCA) with frequency-domain …
Opencollab: A Blockchain Based Protocol To Incentivize Open Source Software Development, Yondon Fu
Opencollab: A Blockchain Based Protocol To Incentivize Open Source Software Development, Yondon Fu
Dartmouth College Undergraduate Theses
Open source software is one of the fundamental building blocks of today's technology dependent society and is relied upon by parties ranging from large technology corporations to individual hobbyist developers. The open question left for technologists is how to make open source software projects more sustainable. The rise of decentralized networks of self-organizing, self-coordinating users incentivized by valuable cryptographic tokens enabled by Ethereum smart contracts creates the possibility of a system with embedded economics for open source software development that aligns the incentives of all parties. We present two contributions that can serve as building blocks for a potentially better …
Novenanetwork: A Catholic Social Media Ios Application For Praying Novenas As A Community, Marissa Le Coz
Novenanetwork: A Catholic Social Media Ios Application For Praying Novenas As A Community, Marissa Le Coz
Dartmouth College Undergraduate Theses
Recent years have seen the rise of a Catholic presence on the Internet and on social media in particular. At the same time, there has been a movement among young Catholics to rediscover and revitalize the traditions of the Church. Novenas, an ancient form of spirituality involving praying for nine consecutive days for some special purpose, are one such tradition. NovenaNetwork, which debuted in the App Store on May 23, 2017 and acquired over 50 users in three countries within its first six days, is an iOS social media application for praying novenas with others. While multiple apps and websites …
Chinese Font Style Transfer With Neural Network, Xue Hanyu
Chinese Font Style Transfer With Neural Network, Xue Hanyu
Dartmouth College Master’s Theses
Font design is an important area in digital art. However, designers have to design character one by one manually. At the same time, Chinese contains more than 20,000 characters. Chinese offical dataset GB 18030-2000 has 27,533 characters. ZhongHuaZiHai, an official Chinese dictionary, contains 85,568 characters. And JinXiWenZiJing, an dataset published by AINet company, includes about 160,000 chinese characters. Thus Chinese font design is a hard task. In the paper, we introduce a method to help designers finish the process faster. With the method, designers only need to design a small set of Chinese characters. Other characters will be generated automatically. …
Accuracy And Racial Biases Of Recidivism Prediction Instruments, Julia J. Dressel
Accuracy And Racial Biases Of Recidivism Prediction Instruments, Julia J. Dressel
Dartmouth College Undergraduate Theses
Algorithms have recently become prevalent in the criminal justice system. Tools known as recidivism prediction instruments (RPIs) are being used all over the country to assess the likelihood that a criminal defendant will reoffend at some point in the future. In June of 2016, researchers at ProPublica published an analysis claiming an RPI called COMPAS was biased against black defendants. This claim sparked a nation-wide debate as to how fairness of an algorithm should be measured, and exposed the many ways that algorithms are not necessarily fair. Algorithms are used in the criminal justice system because they are regarded as …
Assemble.Live: Designing For Schisms In Large Groups In Audio/Video Calls, Benjamin P. Packer
Assemble.Live: Designing For Schisms In Large Groups In Audio/Video Calls, Benjamin P. Packer
Dartmouth College Undergraduate Theses
Although new communication technologies have compressed the space and latency between participants, leading to new forms of computer mediated interaction that scale with the number of participants [Klein, 1999], there still exist no audio/video calling solutions that can accommodate the type of group conversation that takes place in a group of four or more. Groups of this size frequently schism, forming two or more sub-conversations with their own independently operating turn taking systems [Egbert, 1997]. This paper proposes that traditional audio/video calling fails to accommodate schisms because a) there is no way to signal intended recipiency, b) there exists only …
Using Computational Models To Understand Asd Facial Expression Recognition Patterns, Irene L. Feng
Using Computational Models To Understand Asd Facial Expression Recognition Patterns, Irene L. Feng
Dartmouth College Undergraduate Theses
Recent advances in computer vision have led to interest in studying how computer vision can simulate our own perception to better understand the intricacies of human neurobiology. Researchers have made strides in computer vision to imitate many facets of human perception, such as object detection, character recognition, and face identification. However, there have been fewer studies that try to model atypical human perception. My thesis focuses specifically on individuals with Autism Spectrum Disorder (ASD) and their deficit in the facial expression recognition (FER) task. I built multiple computer vision models using hand-crafted features and also convolutional neural network architectures to …
Scene Classification From Degraded Images: Comparing Human And Computer Vision Performance, Tim M. Tadros
Scene Classification From Degraded Images: Comparing Human And Computer Vision Performance, Tim M. Tadros
Dartmouth College Undergraduate Theses
People can recognize the context of a scene with just a brief glance. Visual information such as color, objects and their properties, and texture are all important in correctly determining the type of scene (e.g. indoors versus outdoors). Although these properties are all useful, it is unclear which features of an image play a more important role in the task of scene recognition. To this aim, we compare and contrast a state-of-the-art neural network and GIST model with human performance on the task of classifying images as indoors or outdoors. We analyze the impact of image manipulations, such as blurring …
Improving Elementary Math Learning Through Ipad Games, Kaya M. Thomas
Improving Elementary Math Learning Through Ipad Games, Kaya M. Thomas
Dartmouth College Undergraduate Theses
Mathematics has proven to be challenging to many from a very young age. Young students are influenced by their teachers on how to feel about math and how well they can perform. Currently many methods of teaching mathematics do not encourage learning, but instead promote memorization which has been shown to increase students' anxiety about math. Math anxiety affects student performance as well as their ability to understand the material. Fractions are one of the most difficult concepts for young students to learn. Various techniques have been created in order to better instruct students on how to understand fractions. More …
A Survey Of Trustworthy Computing On Mobile & Wearable Systems, Travis Peters
A Survey Of Trustworthy Computing On Mobile & Wearable Systems, Travis Peters
Computer Science Technical Reports
Mobile and wearable systems have generated unprecedented interest in recent years, particularly in the domain of mobile health (mHealth) where carried or worn devices are used to collect health-related information about the observed person. Much of the information - whether physiological, behavioral, or social - collected by mHealth systems is sensitive and highly personal; it follows that mHealth systems should, at the very least, be deployed with mechanisms suitable for ensuring confidentiality of the data it collects. Additional properties - such as integrity of the data, source authentication of data, and data freshness - are also desirable to address other …
Activityaware: Wearable System For Real-Time Physical Activity Monitoring Among The Elderly, George G. Boateng
Activityaware: Wearable System For Real-Time Physical Activity Monitoring Among The Elderly, George G. Boateng
Dartmouth College Master’s Theses
Physical activity helps reduce the risk of cardiovascular disease, hypertension and obesity. The ability to monitor a person’s daily activity level can inform self-management of physical activity and related interventions. For older adults with obesity, the importance of regular, physical activity is critical to reduce the risk of long-term disability. In this work, we present ActivityAware, an application on the Amulet wrist-worn device that monitors the daily activity levels (low, moderate and vigorous) of older adults in real-time. The app continuously collects acceleration data on the Amulet, classifies the current activity level, updates the day’s accumulated time spent at that …
Safety And Immunogenicity Of An Inactivated Whole Cell Tuberculosis Vaccine Booster In Adults Primed With Bcg: A Randomized, Controlled Trial Of Dar-901, C. Fordham Von Reyn, Timothy Lahey, Robert D. Arbeit, Bernard Landry, Leway Kailani, Lisa Adams, Brenda Haynes, Todd Mackenzie, Wendy Wieland-Alter, Ruth Connor, Sue Tvaroha, David Hokey, Ann Ginsberg, Richard Waddell
Safety And Immunogenicity Of An Inactivated Whole Cell Tuberculosis Vaccine Booster In Adults Primed With Bcg: A Randomized, Controlled Trial Of Dar-901, C. Fordham Von Reyn, Timothy Lahey, Robert D. Arbeit, Bernard Landry, Leway Kailani, Lisa Adams, Brenda Haynes, Todd Mackenzie, Wendy Wieland-Alter, Ruth Connor, Sue Tvaroha, David Hokey, Ann Ginsberg, Richard Waddell
Dartmouth Scholarship
Development of a tuberculosis vaccine to boost BCG is a major international health priority. SRL172, an inactivated whole cell booster derived from a non-tuberculous mycobacterium, is the only new vaccine against tuberculosis to have demonstrated efficacy in a Phase 3 trial. In the present study we sought to determine if a three-dose series of DAR-901 manufactured from the SRL172 master cell bank by a new, scalable method was safe and immunogenic.
Single-Crystal Ih Ice Surfaces Unveil Connection Between Macroscopic And Molecular Structure, Alexandra Brumberg, Kevin Hammonds, Ian Baker, Ellen H.G Backus, Patrick J. Bisson, Mischa Bonn, Charles P. Daghlian, Markus Mezger, Mary Jane Schultz
Single-Crystal Ih Ice Surfaces Unveil Connection Between Macroscopic And Molecular Structure, Alexandra Brumberg, Kevin Hammonds, Ian Baker, Ellen H.G Backus, Patrick J. Bisson, Mischa Bonn, Charles P. Daghlian, Markus Mezger, Mary Jane Schultz
Dartmouth Scholarship
Physics and chemistry of ice surfaces are not only of fundamental interest but also have important impacts on biological and environmental processes. As ice surfaces—particularly the two prism faces—come under greater scrutiny, it is increasingly important to connect the macroscopic faces with the molecular-level structure. The microscopic structure of the ubiquitous ice Ih crystal is well-known. It consists of stacked layers of chair-form hexagonal rings referred to as molecular hexagons. Crystallographic unit cells can be assembled into a regular right hexagonal prism. The bases are labeled crystallographic hexagons. The two hexagons are rotated 30° with respect to each other. …
Cryptographic Transfer Of Sensor Data From The Amulet To A Smartphone, David B. Harmon
Cryptographic Transfer Of Sensor Data From The Amulet To A Smartphone, David B. Harmon
Dartmouth College Undergraduate Theses
The authenticity, confidentiality, and integrity of data streams from wearable healthcare devices are critical to patients, researchers, physicians, and others who depend on this data to measure the effectiveness of treatment plans and clinical trials. Many forms of mHealth data are highly sensitive; in the hands of unintended parties such data may reveal indicators of a patient's disorder, disability, or identity. Furthermore, if a malicious party tampers with the data, it can affect the diagnosis or treatment of patients, or the results of a research study. Although existing network protocols leverage encryption for confidentiality and integrity, network-level encryption does not …
A Hololens Application To Aid People Who Are Visually Impaired In Navigation Tasks, Jonathan L. Huang
A Hololens Application To Aid People Who Are Visually Impaired In Navigation Tasks, Jonathan L. Huang
Dartmouth College Undergraduate Theses
Day-to-day activities such as navigation and reading can be particularly challenging for people with visual impairments. Reading text on signs may be especially difficult for people who are visually impaired because signs have variable color, contrast, and size. Indoors, signage may include office, classroom, restroom, and fire evacuation signs. Outdoors, they may include street signs, bus numbers, and store signs. Depending on the level of visual impairment, just identifying where signs exist can be a challenge. Using Microsoft's HoloLens, an augmented reality device, I designed and implemented the TextSpotting application that helps those with low vision identify and read indoor …
Lighttouch: Securely Connecting Wearables To Ambient Displays With User Intent, Xiaohui Liang, Tianlong Yun, Ronald Peterson, David Kotz
Lighttouch: Securely Connecting Wearables To Ambient Displays With User Intent, Xiaohui Liang, Tianlong Yun, Ronald Peterson, David Kotz
Dartmouth Scholarship
Wearables are small and have limited user interfaces, so they often wirelessly interface with a personal smartphone/computer to relay information from the wearable for display or other interactions. In this paper, we envision a new method, LightTouch, by which a wearable can establish a secure connection to an ambient display, such as a television or a computer monitor, while ensuring the user's intention to connect to the display. LightTouch uses standard RF methods (like Bluetooth) for communicating the data to display, securely bootstrapped via the visible-light communication (the brightness channel) from the display to the low-cost, low-power, ambient light sensor …
Salting Our Freshwater Lakes, Hilary A. Dugan, Sarah L. Bartlett, Samantha M. Burke, Jonathan P. Doubek, Flora Krivak-Tetley
Salting Our Freshwater Lakes, Hilary A. Dugan, Sarah L. Bartlett, Samantha M. Burke, Jonathan P. Doubek, Flora Krivak-Tetley
Dartmouth Scholarship
The highest densities of lakes on Earth are in north temperate ecosystems, where increasing urbanization and associated chloride runoff can salinize freshwaters and threaten lake water quality and the many ecosystem services lakes provide. However, the extent to which lake salinity may be changing at broad spatial scales remains unknown, leading us to first identify spatial patterns and then investigate the drivers of these patterns. Significant decadal trends in lake salinization were identified using a dataset of long-term chloride concentrations from 371 North American lakes. Landscape and climate metrics calculated for each site demonstrated that impervious land cover was a …
Dust-Polarization Maps And Interstellar Turbulence, Robert R. Caldwell, Chris Hirata, Marc Kamionkowski
Dust-Polarization Maps And Interstellar Turbulence, Robert R. Caldwell, Chris Hirata, Marc Kamionkowski
Dartmouth Scholarship
Perhaps the most intriguing result of Planck's dust-polarization measurements is the observation that the power in the E-mode polarization is twice that in the B mode, as opposed to pre-Planck expectations of roughly equal dust powers in the E and B modes. Here we show how the E- and B-mode powers depend on the detailed properties of the fluctuations in the magnetized interstellar medium (ISM). These fluctuations can be decomposed into slow, fast, and Alfvén magnetohydrodynamic (MHD) waves, which comprise a complete basis that can be used to describe linear fluctuations of a magnetized fluid. They can …
Mermin Inequalities For Perfect Correlations In Many-Qutrit Systems, Jay Lawrence
Mermin Inequalities For Perfect Correlations In Many-Qutrit Systems, Jay Lawrence
Dartmouth Scholarship
The existence of Greenberger-Horne-Zeilinger (GHZ) contradictions in many-qutrit systems was a long-standing theoretical question until its (affirmative) resolution in 2013. To enable experimental tests, we derive Mermin inequalities from concurrent observable sets identified in those proofs. These employ a weighted sum of observables, called M, in which every term has the chosen GHZ state as an eigenstate with eigenvalue unity. The quantum prediction for M is then just the number of concurrent observables, and this grows asymptotically as 2N/3 as the number of qutrits N→∞. The maximum classical value falls short for every N≥3, so that the quantum to classical …
Annual Variation In Event-Scale Precipitation Δ 2 H At Barrow, Ak, Reflects Vapor Source Region, Annie Putman, Xiahong Feng, Leslie Sonder, Eric Posmentier
Annual Variation In Event-Scale Precipitation Δ 2 H At Barrow, Ak, Reflects Vapor Source Region, Annie Putman, Xiahong Feng, Leslie Sonder, Eric Posmentier
Dartmouth Scholarship
In this study, precipitation isotopic variations at Barrow, AK, USA, are linked to conditions at the moisture source region, along the transport path, and at the precipita- tion site. Seventy precipitation events between January 2009 and March 2013 were analyzed for δ2H and deuterium ex- cess. For each precipitation event, vapor source regions were identified with the hybrid single-particle Lagrangian inte- grated trajectory (HYSPLIT) air parcel tracking program in back-cast mode. The results show that the vapor source re- gion migrated annually, with the most distal (proximal) and southerly (northerly) vapor source regions occurring during the winter (summer). This may …
Absolute Ages And Distances Of 22 Gcs Using Monte Carlo Main-Sequence Fitting, Erin M. O'Malley, Christina Gilligan, Brian Chaboyer
Absolute Ages And Distances Of 22 Gcs Using Monte Carlo Main-Sequence Fitting, Erin M. O'Malley, Christina Gilligan, Brian Chaboyer
Dartmouth Scholarship
The recent Gaia Data Release 1 of stellar parallaxes provides ample opportunity to find metal-poor main-sequence stars with precise parallaxes. We select 21 such stars with parallax uncertainties better than σ π /π ≤ 0.10 and accurate abundance determinations suitable for testing metal-poor stellar evolution models and determining the distance to Galactic globular clusters (GCs). A Monte Carlo analysis was used, taking into account uncertainties in the model construction parameters, to generate stellar models and isochrones to fit to the calibration stars. The isochrones that fit the calibration stars best were then used to determine the distances and ages …