Browsing by Author "Li, Xuan"

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    Behavioral modeling of integrated phase-change photonic devices for neuromorphic computing applications
    (APL Materials, 2019) Carrillo, Santiago G.-C.; Gemo, Emanuele; Li, Xuan; Youngblood, Nathan; Katumba, Andrew; Bienstman, Peter; Pernice, Wolfram; Bhaskaran, Harish; Wright, C. David
    The combination of phase-change materials and integrated photonics has led to the development of new forms of all-optical devices, including photonic memories, arithmetic and logic processors, and synaptic and neuronal mimics. Such devices can be readily fabricated into photonic integrated circuits, so potentially delivering large-scale all-optical arithmetic-logic units and neuromorphic processing chips. To facilitate in the design and optimization of such large-scale systems, and to aid in the understanding of device and system performance, fast yet accurate computer models are needed. Here, we describe the development of a behavioral modeling tool that meets such requirements, being capable of essentially instantaneous modeling of the write, erase, and readout performance of various integrated phase-change photonic devices, including those for synaptic and neuronal mimics.
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    A behavioural model for integrated phase-change photonics devices
    (European Phase Change and Ovonics Symposium, 2017) Carrillo, Santiago G-C; Gemo, Emanuele; Youngblood, Nathan; Li, Xuan; Katumba, Andrew; Bienstman, Peter; Pernice, Wolfram; Bhaskaran, Harish; Wright, C. David
    The use of phase-change materials in integrated photonics applications has enabled the development of new types of all-optical devices, including multilevel photonic memories, arithmetic and logic processors and synaptic and neuron mimics. In order to design, optimise and understand the performance of large-scale systems, fast and accurate material and device models are needed. Here we present a behavioural model for phase-change photonic devices that can simulate the write, erase and readout operations in time spans compatible with system level performance evaluation.
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    Co-occurrence of and factors associated with health risk behaviors among adolescents: a multi-center study in sub-Saharan Africa, China, and India
    (Elsevier Ltd, 2024-04) Li, Xuan; Dessie, Yadeta; Mwanyika-Sando, Mary; Assefa, Nega; Millogo, Ourohiré; Manu, Adom; Chukwu, Angela; Bukenya, Justine; Patil, Rutuja; Zou, Siyu; Zhang, Hanxiyue; Nurhussien, Lina; Tinkasimile, Amani; Bärnighausen, Till; Shinde, Sachin; Fawzi, Wafaie W; Tang, Kun
    Abstract Despite lifelong and detrimental effects, the co-occurrence of health risk behaviors (HRBs) during adolescence remains understudied in low- and middle-income countries. This study examines the co-occurrence of HRBs and its correlates among adolescents in sub-Saharan Africa, China, and India. A multi-country cross-sectional study was conducted in 2021-2022, involving 9697 adolescents (aged 10-19 years) from eight countries, namely Burkina Faso, China, Ethiopia, India, Ghana, Nigeria, Tanzania, and Uganda. A standardized questionnaire was administered to examine five types of HRBs - physical inactivity, poor dietary habits, smoking, alcohol consumption, and risky sexual behavior. Latent class analysis was employed to identify clustering patterns among the behaviors, and logistic regression was used to identify the correlates of these patterns. Three clusters of HRBs were identified, with Cluster 1 (27.73%) characterized by the absence of any specific risky behavior, Cluster 2 (68.16%) characterized by co-occurrence of physical inactivity and poor dietary habits, and Cluster 3 (4.11%) characterized by engagement in smoking, alcohol consumption, and risky sexual behavior. Relative to Cluster 1, being in Cluster 2 was associated with being female (aOR 1.20, 95% CI 1.09-1.32), not enrolled in education (aOR 0.84, 95% CI 0.71-0.99), and not engaged in paid work (aOR 1.23, 95% CI 1.08-1.41). Compared with those Cluster 1, adolescents in Cluster 3 were less likely to be female (aOR 0.41, 95% CI 0.32-0.54), be engaged in paid work (aOR 0.54, 95% CI 0.41-0.71), more likely to be older (aOR 7.56, 95% CI 5.18-11.03), not be enrolled in educational institution (aOR 1.74, 95% CI 1.27-2.38), and more likely to live with guardians other than parents (aOR 1.56, 95% CI 1.19-2.05). The significant clustering patterns of HRBs among adolescents in sub-Saharan Africa, China, and India highlights the urgent need for convergent approaches to improve adolescent health behaviors. Early life and school-based programs aimed at promoting healthy behaviors and preventing risky and unhealthy behaviors should be prioritized to equip adolescents with the tools and skills for lifelong well-being. Fondation Botnar (Grant #INV-037672) and Harvard T.H. Chan School of Public Health, partially funded this study. PubMed