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1. Performance testing and end-to-end mapping of the fiber cable on the SALT NIR integral field spectrograph

   https://doi.org/10.1117/12.2630176  

   Oppor, Joshua E.; Bershady, Matthew A.; Wolf, Marsha J.; Smith, Michael P.; Chattopadhyay, Sabyasachi; Jaehnig, Kurt P.; Percival, Jeffrey W.; Mulligan, Mark P.; Jurgella, Kathleen M.; Wirag, Briana (August 2022, Performance testing and end-to-end mapping of the fiber cable on the SALT NIR integral field spectrograph)

   Geyl, Roland; Navarro, Ramón (Ed.)

   The optical fiber integral field unit (IFU) built to feed the near infrared (NIR) spectrograph for the 11-meter Southern African Large Telescope (SALT) has undergone prototyping and rigorous performance testing at Wash- burn Astronomical Laboratories of the University of Wisconsin-Madison Astronomy Department. The 43 m length of 256 fibers which make up the object and sky arrays and spares are routed from the SALT payload down into the spectrograph room in four separate cables. The IFU covers 344 arcsec2 on the sky, with the object array spanning a 552 arcsec2 near-rectangular area at roughly 56% fill-factor. Companion papers describe the mechanical design of the fiber cable that mitigates potential sources of mechanical strain on the optical fiber (Smith et al.) and details of the spectrograph (Wolf et al.). Here we present the results of the performance testing of various test cables as well as performance testing and end-to-end mapping of the fully-assembled science cable. The fiber optics experience an extreme temperature gradient at the ingress to the instrument enclosure held at -40 ◦C during operation. We find an increase in focal ratio degradation (FRD) when holding progressively longer lengths of test fiber at reduced temperature. However, we confirm that this temperature dependent FRD is negligible for our designed length of cold fiber. We also find negligible contributions to FRD from the rubber seal that breaches the room temperature strain relief box and the cold instrument enclosure. Our measure- ments characterize performance including the effects of internal fiber inhomogeneities, stress induced from fiber handling and termination, as well as any imperfections from end-polishing. We present the room-temperature laboratory performance measurements of the fully-assembled science cable; the effective total throughput the fiber cable delivers to the spectrograph collimator is 81±2.5% across all fibers accounting for all losses. 

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2. Visualizing fiber end geometry effects on stress distribution in composites using mechanophores

   https://doi.org/10.1039/D4SM00967C  

   Haque, Nazmul; Chang, Hao Chun; Chang, Chia-Chih; Davis, Chelsea S (January 2025, Soft Matter)

   Stress quantification can be observed during single fiber pull-out test in a polymer matrix composite with stress sensing molecules. 

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3. High resolution, fast response fiber-optic temperature sensor with reduced end conduction effect

   https://doi.org/10.1364/OL.405604  

   Sheng, Qiwen; Li, Bo; Uddin, Nezam; Mitul, Abu_Farzan; Zhu, Yupeng; Qiu, Zhen; Han, Ming (November 2020, Optics Letters)

   We report a fiber-optic silicon Fabry–Perot temperature sensor with high speed by considering the end conduction effect, which refers to the unwanted heat transfer between the sensing element and the fiber stub delaying the sensor from reaching thermal equilibrium with the ambient environment. The sensor is constructed by connecting the narrow edge surface of a thin silicon plate to the edge of the microtube attached to the fiber tip. Compared to the traditional design where the silicon plate is attached to the fiber end face on its large plate surface, the new sensor design minimizes the heat transfer path to the fiber stub for improved sensor speed. It has the additional benefit of increased cavity length for improved resolution. We show that, compared with the sensor of traditional design, the sensor of the new design shortened the characteristic response time in still air from 83 ms to 13 ms and improved the sensor resolution by a factor of 12, from 0.15 K to 0.012 K. 

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4. The End-to-End Provenance Project

   https://doi.org/10.1016/j.patter.2020.100016  

   Ellison, Aaron M.; Boose, Emery R.; Lerner, Barbara S.; Fong, Elizabeth; Seltzer, Margo (May 2020, Patterns)
5. End-to-end programmable computing systems

   https://doi.org/10.1038/s44172-023-00127-7  

   Xiao, Yao; Ma, Guixiang; Ahmed, Nesreen_K; Capotă, Mihai; Willke, Theodore_L; Nazarian, Shahin; Bogdan, Paul (November 2023, Communications Engineering)

   Abstract Recent technological advances have contributed to the rapid increase in algorithmic complexity of applications, ranging from signal processing to autonomous systems. To control this complexity and endow heterogeneous computing systems with autonomous programming and optimization capabilities, we propose aunified, end-to-end, programmable graph representation learning(PGL) framework that mines the complexity of high-level programs down to low-level virtual machine intermediate representation, extracts specific computational patterns, and predicts which code segments run best on a core in heterogeneous hardware. PGL extracts multifractal features from code graphs and exploits graph representation learning strategies for automatic parallelization and correct assignment to heterogeneous processors. The comprehensive evaluation of PGL on existing and emerging complex software demonstrates a 6.42x and 2.02x speedup compared to thread-based execution and state-of-the-art techniques, respectively. Our PGL framework leads to higher processing efficiency, which is crucial for future AI and high-performance computing applications such as autonomous vehicles and machine vision. 

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