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1. Timely Lossless Source Coding for Randomly Arriving Symbols

   https://doi.org/10.1109/ITW.2018.8613380  

   Zhong, Jing; Yates, Roy D.; Soljanin, Emina (November 2018, 2018 IEEE Information Theory Workshop (ITW))

   We consider a real-time streaming source coding system in which an encoder observes a sequence of randomly arriving symbols from an i.i.d. source, and feeds binary code-words to a FIFO buffer that outputs one bit per time unit to a decoder. Each source symbol represents a status update by the source, and the timeliness of the system is quantified by the age of information (AoI), defined as the time difference between the present time and the generation time of the most up-to-date symbol at the output of the decoder. When the FIFO buffer is allowed to be empty, we propose an optimal prefix-free lossless coding scheme that minimizes the average peak age based on the analysis of discrete-time Geo/G/1 queue. For more practical scenarios in which a special codeword is reserved for indicating an empty buffer, we propose an encoding scheme that assigns a codeword to the empty buffer state based on an estimate of the buffer idle time. 

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2. Nitride perovskite becomes polar

   https://doi.org/10.1126/science.abm7179  

   Hong, Xia (December 2021, Science)

   There is a strong drive behind the quest for thin-film materials that are oxygen-free and polar. Oxygen hinders the integration of ferroelectric oxides with semiconductors, which affects efforts to develop nonvolatile memory—that is, a memory that can sustain its information without power. Ideally, one would use single-crystalline perovskite films to construct these devices so that the polarization can be maximized. However, when depositing crystalline polar perovskite oxides onto silicon or germanium, a nonpolar oxide buffer layer ( 1 ) or a native oxide layer ( 2 ) can be present at the interface, compromising device performance. A nitrogen-based perovskite may overcome this limitation ( 3 ). On page 1488 of this issue, Talley et al. ( 4 ) report the synthesis of lanthanum tungsten nitride (LaWN 3 ) thin films, which marks the first demonstration of polar nitride perovskite. This may lead to oxygen-free integration of functional perovskite on a semiconductor platform. 

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3. How pipefitters obtain visual information from construction assembly drawings

   https://doi.org/10.36680/j.itcon.2022.015  

   Sears, Matthew; Alruwaythi, Omar; Goodrum, Paul M. (January 2022, Journal of Information Technology in Construction)

   An extensive framework has been developed for studying the behavior of motor vehicle drivers using eye tracking technology. Previous work has revealed strong relationships between driver eye movements and performance, which has resulted in widely accepted guidance within the transportation industry. In this work, the same eye tracking analysis methods were applied to investigate 20 professional pipefitters’ interactions with traditional isometric assembly drawings during a construction pipe model assembly task, in order to begin to understand the strategies that construction craft professionals use to gather visual information from engineering deliverables. A custom web application was developed to quantify and compare the pipefitters’ interactions with the assembly drawings through several visit metrics. Results indicated that the pipefitters’ interactions with the assembly drawings were associated with their performance and spatial cognition; however, the results did not suggest that the pipefitters were adhering to any particular visual information gathering strategies. The authors also investigated whether age or industry experience were associated with differences in visual information gathering strategies, but no significant relationships were observed. The primary contribution of this work is a demonstration of how existing eye tracking analysis methods can be applied to investigate how construction craft professionals extract visual information from engineering deliverables. 

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4. Highly Efficient Solar‐Driven Carbon Dioxide Reduction on Molybdenum Disulfide Catalyst Using Choline Chloride‐Based Electrolyte

   Mohammad Asadi, Mohammad Hossein (January 2019, Advanced energy materials)

   Conversion of CO2 to energy‐rich chemicals using renewable energy is of much interest to close the anthropogenic carbon cycle. However, the current photoelectrochemical systems are still far from being practically feasible. Here the successful demonstration of a continuous, energy efficient, and scalable solar‐driven CO2 reduction process based on earth‐abundant molybdenum disulfide (MoS2) catalyst, which works in synergy with an inexpensive hybrid electrolyte of choline chloride (a common food additive for livestock) and potassium hydroxide (KOH) is reported. The CO2 saturated hybrid electrolyte utilized in this study also acts as a buffer solution (pH ≈ 7.6) to adjust pH during the reactions. This study reveals that this system can efficiently convert CO2 to CO with solar‐to‐fuel and catalytic conversion efficiencies of 23% and 83%, respectively. Using density functional theory calculations, a new reaction mechanism in which the water molecules near the MoS2 cathode act as proton donors to facilitate the CO2 reduction process by MoS2 catalyst is proposed. This demonstration of a continuous, cost‐effective, and energy efficient solar driven CO2 conversion process is a key step toward the industrialization of this technology. 

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5. Extreme Event Analysis in Next Generation Simulation Architectures

   https://doi.org/10.1007/978331958667015  

   Hamilton, S.; Lindstrom, P.; Patchett, J.; Meneveau, C.; Burns, R. (May 2017, High Performance Computing. ISC 2017. Lecture Notes in Computer Science)

   Numerical simulations present challenges because they generate petabyte-scale data that must be extracted and reduced during the simulation. We demonstrate a seamless integration of feature extraction for a simulation of turbulent fluid dynamics. The simulation produces on the order of 6 TB per timestep. In order to analyze and store this data, we extract velocity data from a dilated volume of the strong vortical regions and also store a lossy compressed representation of the data. Both reduce data by one or more orders of magnitude. We extract data from user checkpoints in transit while they reside on temporary burst buffer SSD stores. In this way, analysis and compression algorithms are designed to meet specific time constraints so they do not interfere with simulation computations. Our results demonstrate that we can perform feature extraction on a world-class direct numerical simulation of turbulence while it is running and gather meaningful scientific data for archival and post analysis. 

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