arXiv subjects

Qingyou Meng

Publications and source records attributed to Qingyou Meng.

4 recordsLinked to original sources

arXiv2025

A Principle-based Framework for the Development and Evaluation of Large Language Models for Health and Wellness

The incorporation of generative artificial intelligence into personal health applications presents a transformative opportunity for personalized, data-driven health and fitness guidance, yet also poses challenges related to user safety, model accuracy, and personal privacy. To address these challenges, a novel, principle-based framework was developed and validated for the systematic evaluation of LLMs applied to personal health and wellness. First, the development of the Fitbit Insights explorer, a large language model (LLM)-powered system designed to help users interpret their personal health data, is described. Subsequently, the safety, helpfulness, accuracy, relevance, and personalization (SHARP) principle-based framework is introduced as an end-to-end operational methodology that integrates comprehensive evaluation techniques including human evaluation by generalists and clinical specialists, autorater assessments, and adversarial testing, into an iterative development lifecycle. Through the application of this framework to the Fitbit Insights explorer in a staged deployment involving over 13,000 consented users, challenges not apparent during initial testing were systematically identified. This process guided targeted improvements to the system and demonstrated the necessity of combining isolated technical evaluations with real-world user feedback. Finally, a comprehensive, actionable approach is established for the responsible development and deployment of LLM-powered health applications, providing a standardized methodology to foster innovation while ensuring emerging technologies are safe, effective, and trustworthy for users.

cs.HC↗

arXiv2021

Defects in Conformal Crystals: Discrete vs. Continuous Disclination Models

We study the relationship between topological defect formation and ground-state packings in a model of repulsions in external confining potentials. Specifically we consider screened 2D Coulombic repulsions, which conveniently parameterizes the effects of interaction range, but also serves as simple physical model of confined, parallel arrays of polyelectrolyte filaments or vortices in type-II superconductors. The countervailing tendencies of repulsions and confinement to, respectively, spread and concentrate particle density leads to an energetic preference for non-uniform densities in the clusters. Ground states in such systems have previously been modeled as {\it conformal crystals}, which are composed of locally equitriangular packings whose local areal densities exhibit long range gradients. Here, we assess two theoretical models that connect the preference for non-uniform density to the formation of disclination defects, one of which assumes a continuum distributions of defect, while the second considers the quantized and localized nature of disclinations in hexagonal conformal crystals. Comparing both models to numerical simulations of discrete particles clusters, we study the influence of interaction range and confining potential on defects in ground states. We show that treating disclinations as continuously distributable well-captures the number of topological defects in the ground state in the regime of long-range interactions, while as interactions become shorter range, it dramatically overpredicts the to growth in total defect charge. Analysis of the discretized defect theory suggests that limitations of the continuous defect theory can be attributed to the asymmetry in the placement of positive vs. negative disclinations in the conformal crystal ground states, as well as a strongly asymmetric dependence of self-energy of disclinations on sign of topological charge.

cond-mat.soft↗

arXiv2016

Phase diagrams of vortex matter with multi-scale inter-vortex interactions in layered superconductors

It was recently proposed to use the stray magnetic fields of superconducting vortex lattices to trap ultracold atoms for building quantum emulators. This calls for new methods for engineering and manipulating of the vortex states. One of the possible routes utilizes type-1.5 superconducting layered systems with multi-scale inter-vortex interactions. In order to explore the possible vortex states that can be engineered, we present two phase diagrams of phenomenological vortex matter models with multi-scale inter-vortex interactions featuring several attractive and repulsive length scales. The phase diagrams exhibit a plethora of phases, including conventional 2D lattice phases, five stripe phases, dimer, trimer, and tetramer phases, void phases, and stable low-temperature disordered phases. The transitions between these states can be controlled by the value of an applied external field.

cond-mat.supr-con↗

arXiv2014

Honeycomb, square, and kagomé vortex lattices in superconducting systems with multi-scale inter-vortex interactions

The recent proposal of Romero-Isart {\em et al.}~\cite{romero-isart_superconducting_2013} to utilize the vortex lattice phases of superconducting materials to prepare a lattice for ultra-cold atoms-based quantum emulators, raises the need to create and control vortex lattices of different symmetries. Here we propose a mechanism by which honeycomb, hexagonal, square, and kagomé vortex lattices could be created in superconducting systems with multi-scale inter-vortex interaction. Multiple scales of the inter-vortex interaction can be created and controlled in layered systems made of different superconducting material or with differing interlayer spacing.

cond-mat.supr-con↗