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The Structure of Cross-National Collaboration in Open-Source Software Development
No full textCIKM ’25, Seoul, Republic of KoreaOpen-source software (OSS) development platforms, such as GitHub, expand the potential for cross-national collaboration among developers by lowering the geographic, temporal, and coordination barriers that limited software innovation in the past. However, research has shown that the technological affordances that facilitate cross-national collaboration do not uniformly benefit all countries. Using the GitHub Innovation Graph dataset, which aggregates the complete cross-country collaborations among the entire population of GitHub developers, we present quantitative evidence of deep-seated religious and cultural affinities, shared colonial histories, and geopolitical factors structuring the collaborations between non-U.S. country pairs that become visible when the overarching dominance of the U.S. is removed from the data. This study highlights the opportunities to develop decentralizing strategies to facilitate new collaborations between developers in non-U.S. countries, thereby fostering the development of novel, innovative solutions. More generally, this study also underscores the importance of contextualizing user behavior and knowledge management in information systems with long-term, macro-social conditions in which these systems are inextricably embedded
Recent advances in nanoparticulate RNA delivery systems
No full textNanoparticle-based RNA delivery has shown great progress in recent years with the approval of two mRNA vaccines for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and a liver-targeted siRNA therapy. Here, we discuss the preclinical and clinical advancement of new generations of RNA delivery therapies along multiple axes. Improvements in cargo design such as RNA circularization and data-driven untranslated region optimization can drive better mRNA expression. New materials discovery research has driven improved delivery to extrahepatic targets such as the lung and splenic immune cells, which could lead to pulmonary gene therapy and better cancer vaccines, respectively. Other organs and even specific cell types can be targeted for delivery via conjugation of small molecule ligands, antibodies, or peptides to RNA delivery nanoparticles. Moreover, the immune response to any RNA delivery nanoparticle plays a crucial role in determining efficacy. Targeting increased immunogenicity without induction of reactogenic side effects is crucial for vaccines, while minimization of immune response is important for gene therapies. New developments have addressed each of these priorities. Last, we discuss the range of RNA delivery clinical trials targeting diverse organs, cell types, and diseases and suggest some key advances that may play a role in the next wave of therapies
Expanding Annotation to Mixed-Media Types in a Large-Scale Social Annotation Platform
No full textIn recent years, social annotation systems have become a popular and effective tool for hosting collaborative discussions on assigned readings. One such tool created by our lab is NB. Over the last twelve years, hundreds of instructors have incorporated NB within their classes, with over 50,000 students leaving millions of annotations [1]. While feedback for NB has mostly been positive, one major limitation is its difficulty in annotating documents with nested media types. As multimodal forms of learning beyond just text are becoming increasingly common in educational assignments, having the ability to annotate beyond simple text documents would greatly increase the utility of NB in the modern classroom. This work seeks to remedy this issue by expanding the types of documents NB can successfully annotate, specifically focusing on three mixed-media issue types: independently moving text components, image annotation, and video annotation. We will explore the design space of possible implementation strategies for these features and discuss the specific design decisions that were made when adding them to NB. We hope that by increasing the types of documents NB can annotate, we will better fulfill its goal of enhancing student engagement and learning.M.Eng
How Many Sexes? How Many Genders?
No full textThe British philosopher and public intellectual C. E. M. Joad was a regular panelist on the BBC radio show The Brains Trust during and after the Second World War. He often began an answer to listeners’ questions with his catchphrase “It all depends what you mean by…,” which caught on throughout the country (Ayto & Crofton, 2011). If any question deserves Joad’s catchphrase, it is “How many genders?
A Reconfigurable, Distributed-Memory Accelerator for Sparse Applications
No full textIterative sparse matrix computations lie at the heart of many scientific computing and graph analytics algorithms. On conventional systems, their irregular memory accesses and low arithmetic intensity create challenging memory bandwidth bottlenecks. To overcome such bottlenecks, distributed-SRAM architectures use tiled arrays of high-bandwidth local storage to achieve very high aggregate memory bandwidth. However, current distributedSRAM architectures suffer from either poor programmability due to over-specialization or poor compute performance due to inefficient general-purpose hardware. This thesis proposes Quartz, a new architecture that uses short dataflow tasks and reconfigurable compute in a distributed-SRAM system to deliver both high performance and high programmability. Unlike traditional sparse CGRAs or on-die reconfigurable engines, Quartz allows reconfigurable compute to be highly utilized and scaled by (1) providing high memory bandwidth to each processing element and (2) introducing a task-level dataflow execution model that fits this new setting. Our execution model dynamically reconfigures tile hardware based on inter-tile messages to execute tasks on local data with fine-grained data partitioning across tiles. To make execution efficient, we explore novel data partitioning techniques that use graph and hypergraph partitioning to minimize network traffic and balance load. This is especially challenging for computations where one operand’s sparsity pattern (i.e., distribution of nonzeros) exhibits dynamic behavior across iterations, and we are the first to provide techniques to address this case. To ensure programmability, we show how a wide range of computations (expressed in an extended version of tensor algebra’s Einsum notation) and flexible data distributions can be systematically captured in small tasks for execution on Quartz. We evaluate Quartz in simulation, using an 8-chiplet design with 2,048 tiles and 824 MB of SRAM per chiplet, running six different iterative sparse applications from scientific computing and graph analytics. Quartz’s architecture, data partitioning techniques, and programming model together achieve gmean 26.2× speedup over the prior state-of-the-art programmable distributed-SRAM architecture.S.M
Search for dark matter produced in association with a Higgs boson decaying to a τ lepton pair in proton-proton collisions at √s = 13 TeV
No full textA search for dark matter particles produced in association with a Higgs boson decaying into a pair of τ leptons is performed using data collected in proton-proton collisions at a center-of-mass energy of 13 TeV with the CMS detector. The analysis is based on a data set corresponding to an integrated luminosity of 101 fb−1 collected in 2017–2018. No significant excess over the expected standard model background is observed. This result is interpreted within the frameworks of the 2HDM+a and baryonic Z′ benchmark simplified models. The 2HDM+a model is a type-II two-Higgs-doublet model featuring a heavy pseudoscalar with an additional light pseudoscalar. Upper limits at 95% confidence level are set on the product of the production cross section and the branching fraction for each of these two simplified models. Heavy pseudoscalar boson masses between 400 and 700 GeV are excluded for a light pseudoscalar mass of 100 GeV. For the baryonic Z′ model, a statistical combination is made with an earlier search based on a data set of 36 fb−1 collected in 2016. In this model, Z′ boson masses up to 1050 GeV are excluded for a dark matter particle mass of 1 GeV
Deformable Object Manipulation with a Tactile Reactive Gripper
No full textManipulating deformable objects remains a fundamental challenge in robotics, as techniques developed for rigid objects often fail to generalize. Deformable objects exhibit infinite-dimensional configuration spaces, frequent self-occlusion, and high model uncertainty, making global state estimation and predictive modeling unreliable. To address these challenges, we propose a perception-driven framework that combines global visual understanding with local tactile feedback. Rather than modeling the full configuration of the object, we leverage local constraints, grounded in modular visual and tactile representations, to enable robust, reactive, and generalizable manipulation. The primary contributions of this work include: • Chapter 2: Cable Following. A tactile control strategy for in-hand cable manipulation that decouples contact regulation from object pose control, enabling fast, reactive sliding and closed-loop plug insertion using only local tactile feedback. • Chapter 3: Towel Edge Tracing. An extension of contact-based control to fabric edge following and the learned tactile perception networks to support this capability. • Chapter 4: Visuotactile Grasp Affordance. A grasp affordance model trained in simulation and refined with tactile self-supervision, enabling high-confidence edge grasping on towels. • Chapter 5: Dense Object Correspondence. A confidence-aware dense descriptor representation. Supports correspondence across crumpled and symmetric garments in air and on a table. • Chapter 6: Behavior Architecture and Planning Interfaces. Integration of perception modules into a reactive, confidence-based folding system and an exploration of how dense descriptors can interface with demonstrations, language, and task and motion planning. Collectively, these contributions show that global state estimation and dynamics prediction are not required for reliable deformable manipulation. Instead, semantically meaningful local interactions, guided by modular visual and tactile representations, can drive scalable, long-horizon behaviors across varied objects, configurations, and tasks.Ph.D
Image Registration and Gantry Tracking System of Clytia hemisphaerica
No full textUnderstanding nervous system function and evolution requires detailed behavioral analysis of model organisms such as the jellyfish Clytia hemisphaerica. However, its size and rapid, free-swimming nature pose significant tracking challenges. This work presents a platform for the XY gantry system developed to overcome these hurdles for high-resolution behavioral monitoring. Separately, to prepare for downstream neural analysis, we developed an automated neuron segmentation pipeline - tailored for image registration purposes. Together, the tracking system and the analysis preparation pipeline provide powerful, distinct tools for high-throughput behavioral quantification and facilitate future studies linking behavior to underlying neural dynamics in Clytia hemisphaerica.M.Eng
Ultraviolet-C Powered Air Purifying Respirator (UVC PAPR)
No full textThe global challenge posed by pandemics, notably COVID-19, has underscored the critical need for advanced personal protective equipment (PPE). This thesis details the development and evaluation of a multi-stage powered air-purifying respirator (PAPR) incorporating direct ultraviolet-C (UVC) germicidal irradiation. The proposed PAPR aims to provide enhanced protection by actively sterilizing air through this UVC chamber immediately prior to inhalation. This approach offers an advantage over traditional filter-based PAPRs by removing both the need to replace filters and pull air with high-power motors, while still neutralizing a broad spectrum of airborne pathogens, including viruses and bacteria. The primary objective of this research is to design, construct, and test a PAPR prototype capable of achieving a high inactivation rate (target 99.9%), thereby offering a robust solution for individuals in high-exposure environments. In addition to the UVC chamber, we also built an alternate ultraviolet-A (UVA) activated titanium dioxide (TiO2) photocatalytic oxidation (PCO) chamber. This work encompasses the overall design of the system, safety considerations, and testing to quantify its pathogen inactivation efficacy and to characterize system performance.M.Eng
The Status of Vernier Acuity Following Late Sight Onset
No full textWe possess a remarkably acute ability to detect even small misalignments between extended line segments. This “vernier acuity”significantly exceeds our “resolution acuity”—the ability to resolve closely separated stimuli—and is generally considered a“hyperacuity,” since the detectable misalignments are markedly finer than the diameter of single retinal cones. Vernier acuityhas, thus, often been proposed to reflect spatial organization and multi-unit cortical processing, rendering it an important indexof visual function. Notably, vernier acuity exhibits a characteristic developmental signature: it is inferior to resolution acuity earlyin life but eventually exceeds it by up to one order of magnitude. However, vernier acuity may be disproportionately sensitiveto developmental disruptions. Here, we examined the resilience of acquiring this visual proficiency to early-onset, prolongeddeprivation by longitudinally tracking vernier and resolution acuities in children with dense congenital cataracts who gainedsight late in life as part of Project Prakash. Our data reveal marked longitudinal improvements in both acuity measures andalso demonstrate that, like the normally-sighted, late-sighted individuals’ vernier acuity exceeds their resolution acuity, therebyrendering it a hyperacuity. However, the extent of this hyperacuity is weaker than observed in normally-sighted controls, pointingto partial limitations in postsurgical skill acquisition. Despite these constraints, our findings point to the feasibility of formingsome integrative circuits in the visual system even when inputs are severely compromised, and to the availability of some residualplasticity late in childhood, with implications for the rehabilitation prospects of children following treatment for congenitalcataracts.National Ocean and Atmospheric Administration (NOAA