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1. A Circuit for Simultaneous Reception of Data and Power using a Solar Cell

   https://doi.org/10.1109/TGCN.2021.3087008  

   Kadirvelu, Sindhubala; Leon-Salas, Walter D.; Fan, Xiaozhe; Kim, Jongseok; Peleato, Borja; Mohammadi, Saeed; Vijayalakshmi, B. (June 2021, IEEE Transactions on Green Communications and Networking)

   null (Ed.)

   This paper presents a circuit for simultaneous reception of optical power and data using a solar cell. The circuit employs a switched-inductor boost DC-DC converter for energy harvesting and a low-power thresholding receiver for data reception. The thresholding data receiver comprises a current-sense resistor that monitors the current output of the solar cell, an instrumentation amplifier, a band-pass filter and a comparator. A system-level analysis of an optical communication system employing the proposed circuit is presented along with a circuit-level analysis and implementation. As a proof-of-concept, the proposed circuit for simultaneous power and data reception is implemented using off-the-shelf components and tested using a custom-built test setup. Measurement results, including harvested power, electronic noise and bit error rate (BER), are reported for a GaAs solar cell and a red LED light source. Results show that 223 μW of power are harvested by the DC-DC converter at a distance of 32.5 cm and a radiated power of 9.3 mW. At a modulation depth of 50% and a transmission speed of 2.5 kbps, a BER of 1.008×10^-3 is achieved. Measurement results reveal that the proposed solution exhibits a trade-off between harvested power, transmission speed and BER. 

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2. Exploring Algorithm Building through Designing and Making Kinetic Sculpture

   Huang, J. (June 2023, International Conference of the Learning Sciences (ICLS))

   Algorithm building, creating a step-by-step procedure to carry out a solution, is a challenging concept for youth to learn and practice. Kinetic sculpture is a novel context for examining how students may learn algorithms through designing and making. As part of a larger study, we collected and analyzed a total of 18 student pre- and post-tests on computational thinking, physical computing, and arts. To examine how students build algorithms in the process of designing and making a kinetic sculpture, we analyze two vignettes from two small groups in a STEAM-based workshop. Findings show that while designing and building kinetic sculpture, students learned computational thinking and applied algorithms by incorporating inputs, outputs, and variables during the process. This study offers a springboard to investigate how students create and apply algorithms in designing and making kinetic sculpture and provides empirical evidence on how students learn algorithms in a STEAM learning context. 

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3. A computational interpretation of compact closed categories: reversible programming with negative and fractional types

   https://doi.org/10.1145/3434290  

   Chen, Chao-Hong; Sabry, Amr (January 2021, Proceedings of the ACM on Programming Languages)

   null (Ed.)

   Compact closed categories include objects representing higher-order functions and are well-established as models of linear logic, concurrency, and quantum computing. We show that it is possible to construct such compact closed categories for conventional sum and product types by defining a dual to sum types, a negative type, and a dual to product types, a fractional type. Inspired by the categorical semantics, we define a sound operational semantics for negative and fractional types in which a negative type represents a computational effect that ``reverses execution flow'' and a fractional type represents a computational effect that ``garbage collects'' particular values or throws exceptions. Specifically, we extend a first-order reversible language of type isomorphisms with negative and fractional types, specify an operational semantics for each extension, and prove that each extension forms a compact closed category. We furthermore show that both operational semantics can be merged using the standard combination of backtracking and exceptions resulting in a smooth interoperability of negative and fractional types. We illustrate the expressiveness of this combination by writing a reversible SAT solver that uses backtracking search along freshly allocated and de-allocated locations. The operational semantics, most of its meta-theoretic properties, and all examples are formalized in a supplementary Agda package. 

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4. A new semiconductor: Ti0.5Mg0.5N(001)

   https://doi.org/10.1109/NANOTECH.2018.8653564  

   Wang, Baiwei; Gall, Daniel (November 2018, 2018 IEEE Nanotechnology Symposium (ANTS), Albany, NY, 2018)

   Ti0.5Mg0.5N has recently been predicted to be a semiconductor with a 1.3 eV band gap and promising properties for thermoelectric and plasmonic devices. As a first step towards experimental validation, epitaxial Ti0.5Mg0.5N(001) layers are deposited on MgO(001) by reactive magnetron co-sputtering from titanium and magnesium targets at 600 °C in pure N2 atmospheres. X-ray diffraction ω-2θ scans, ω-rocking curves, φ-scans, and high resolution reciprocal space maps show that Ti0.5Mg0.5N alloys form a pseudobinary rocksalt structure and are single crystals with a cube-on-cube epitaxial relationship with the substrate: (001)TiMgN║(001)MgO and [100]TiMgN║[100]MgO. A 275-nm-thick Ti0.5Mg0.5N layer is fully relaxed and exhibits a 002 ω-rocking curve width ω = 0.73°, while a 36-nm-thick layer is fully strained and has a ω = 0.49°. These results indicate a thickness-dependent strain state which suggests a critical thickness for misfit dislocation nucleation and glide which is between 36 and 275 nm. A measured negative temperature coefficient of resistivity in combination with a low optical absorption coefficient of 0.25 × 105 cm 1 for λ = 740 nm, and a vanishing density of states at the Fermi level measured by x-ray photoelectron spectroscopy support the prediction that Ti0.5Mg0.5N is a semiconductor. 

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5. TMTDyn : A Matlab package for modeling and control of hybrid rigid–continuum robots based on discretized lumped systems and reduced-order models

   https://doi.org/10.1177/0278364919881685  

   Sadati, S.M. Hadi; Naghibi, S. Elnaz; Shiva, Ali; Michael, Brendan; Renson, Ludovic; Howard, Matthew; Rucker, Caleb D.; Althoefer, Kaspar; Nanayakkara, Thrishantha; Zschaler, Steffen; et al (January 2021, The International Journal of Robotics Research)

   null (Ed.)

   A reliable, accurate, and yet simple dynamic model is important to analyzing, designing, and controlling hybrid rigid–continuum robots. Such models should be fast, as simple as possible, and user-friendly to be widely accepted by the ever-growing robotics research community. In this study, we introduce two new modeling methods for continuum manipulators: a general reduced-order model (ROM) and a discretized model with absolute states and Euler–Bernoulli beam segments (EBA). In addition, a new formulation is presented for a recently introduced discretized model based on Euler–Bernoulli beam segments and relative states (EBR). We implement these models in a Matlab software package, named TMTDyn, to develop a modeling tool for hybrid rigid–continuum systems. The package features a new high-level language (HLL) text-based interface, a CAD-file import module, automatic formation of the system equation of motion (EOM) for different modeling and control tasks, implementing Matlab C-mex functionality for improved performance, and modules for static and linear modal analysis of a hybrid system. The underlying theory and software package are validated for modeling experimental results for (i) dynamics of a continuum appendage, and (ii) general deformation of a fabric sleeve worn by a rigid link pendulum. A comparison shows higher simulation accuracy (8–14% normalized error) and numerical robustness of the ROM model for a system with a small number of states, and computational efficiency of the EBA model with near real-time performances that makes it suitable for large systems. The challenges and necessary modules to further automate the design and analysis of hybrid systems with a large number of states are briefly discussed. 

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