More Like this

1. Optimizing LA-ICP-MS analytical procedures for elemental depth profiling of foraminifera shells

   https://doi.org/10.1016/j.chemgeo.2015.04.007  

   Fehrenbacher, Jennifer S. ; Spero, Howard J. ; Russell, Ann D. ; Vetter, Lael ; Eggins, Stephen ( June 2015 , Chemical Geology)
2. Analytical Method to Approximate the Impact of Turning on the Macroscopic Fundamental Diagram

   https://doi.org/10.1177/0361198120933274  

   Xu, Guanhao ; Yu, Zhengyao ; Gayah, Vikash V. ( September 2020 , Transportation Research Record: Journal of the Transportation Research Board)

   null (Ed.)

   Network macroscopic fundamental diagrams (MFDs) have recently been shown to exist in real-world urban traffic networks. The existence of an MFD facilitates the modeling of urban traffic network dynamics at a regional level, which can be used to identify and refine large-scale network-wide control strategies. To be useful, MFD-based modeling frameworks require an estimate of the functional form of a network’s MFD. Analytical methods have been proposed to estimate a network’s MFD by abstracting the network as a single ring-road or corridor and modeling the flow–density relationship on that simplified element. However, these existing methods cannot account for the impact of turning traffic, as only a single corridor is considered. This paper proposes a method to estimate a network’s MFD when vehicles are allowed to turn into or out of a corridor. A two-ring abstraction is first used to analyze how turning will affect vehicle travel in a more general network, and then the model is further approximated using a single ring-road or corridor. This approximation is useful as it facilitates the application of existing variational theory-based methods (the stochastic method of cuts) to estimate the flow–density relationship on the corridor, while accounting for the stochastic nature of turning. Results of the approximation compared with a more realistic simulation that includes features that cannot be captured using variational theory—such as internal origins and destinations—suggest that this approximation works to estimate a network’s MFD when turning traffic is present. 

   more » « less
3. Geospatial divide in real-world EHR data: Analytical workflow to assess regional biases and potential impact on health equity

   Xie SJ, Kapos FP ( October 2022 , Proceedings AMIA Symposium)
4. Milstein-Type Procedures for Numerical Solutions of Stochastic Differential Equations with Markovian Switching

   https://doi.org/10.1137/16M1084730  

   Nguyen, Son L. ; Hoang, Tuan A. ; Nguyen, Dung T. ; Yin, George ( January 2017 , SIAM Journal on Numerical Analysis)
5. Inference for Optimal Differential Privacy Procedures for Frequency Tables

   https://doi.org/10.6339/22-JDS1044  

   Li, Chengcheng ; Wang, Naisyin ; Xu, Gongjun ( January 2022 , Journal of Data Science)

   When releasing data to the public, a vital concern is the risk of exposing personal information of the individuals who have contributed to the data set. Many mechanisms have been proposed to protect individual privacy, though less attention has been dedicated to practically conducting valid inferences on the altered privacy-protected data sets. For frequency tables, the privacy-protection-oriented perturbations often lead to negative cell counts. Releasing such tables can undermine users’ confidence in the usefulness of such data sets. This paper focuses on releasing one-way frequency tables. We recommend an optimal mechanism that satisfies ϵ-differential privacy (DP) without suffering from having negative cell counts. The procedure is optimal in the sense that the expected utility is maximized under a given privacy constraint. Valid inference procedures for testing goodness-of-fit are also developed for the DP privacy-protected data. In particular, we propose a de-biased test statistic for the optimal procedure and derive its asymptotic distribution. In addition, we also introduce testing procedures for the commonly used Laplace and Gaussian mechanisms, which provide a good finite sample approximation for the null distributions. Moreover, the decaying rate requirements for the privacy regime are provided for the inference procedures to be valid. We further consider common users’ practices such as merging related or neighboring cells or integrating statistical information obtained across different data sources and derive valid testing procedures when these operations occur. Simulation studies show that our inference results hold well even when the sample size is relatively small. Comparisons with the current field standards, including the Laplace, the Gaussian (both with/without post-processing of replacing negative cell counts with zeros), and the Binomial-Beta McClure-Reiter mechanisms, are carried out. In the end, we apply our method to the National Center for Early Development and Learning’s (NCEDL) multi-state studies data to demonstrate its practical applicability. 

   more » « less