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Turnkey locking of quantum-dot lasers directly grown on Si

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arXiv 2024年

作者： Dong, Bozhang Wan, Yating Chow, Weng W. Shang, Chen Prokoshin, Artem Koscica, Rosalyn Wang, Heming Bowers, John E. Institute for Energy Efficiency University of California Santa BarbaraCA United States Integrated Photonics Laboratory King Abdullah University of Science and Technology Makkah Province Thuwal Saudi Arabia Sandia National Laboratories AlbuquerqueNM United States Materials Department University of California Santa BarbaraCA United States Department of Electrical and Computer Engineering University of California Santa BarbaraCA United States

Ultra-low-noise laser sources are crucial for a variety of applications, including microwave synthesizers, optical gyroscopes, and the manipulation of quantum systems. Silicon photonics has emerged as a promising solution for high-coherence applications due to its ability to reduce system size, weight, power consumption, and cost (SWaP-C). Semiconductor lasers based on self-injection locking (SIL) have reached fiber laser coherence, but typically require a high-Q external cavity to suppress coherence collapse through frequency-selective feedback. Lasers based on external-cavity locking (ECL) are a low-cost and turnkey operation option, but their coherence is generally inferior to SIL lasers. In this work, we demonstrate quantum-dot (QD) lasers grown directly on Si that achieve SIL laser coherence under turnkey ECL. The high-performance QD laser offers a scalable and low-cost heteroepitaxial integration platform. Moreover, the QD laser’s chaos-free nature enables a 16 Hz Lorentzian linewidth under ECL using a low-Q external cavity, and improves the frequency noise by an additional order of magnitude compared to conventional quantum-well lasers. © 2024, CC BY.

关键词： Quantum dot lasers

FICK’S LAW SELECTS THE NEUMANN BOUNDARY CONDITION

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arXiv 2023年

作者： Hilhorst, Danielle Kang, Seung-Min Kim, Ho-Youn Kim, Yong-Jung CNRS Laboratoire de Mathématiques University Paris-Saclay Cedex Orsay91405 France Department of Mathematical Sciences KAIST 291 Daehakro Yuseong-gu Daejeon34141 Korea Republic of Computer Electrical and Mathematical Sciences and Engineering Division 4700 King Abdullah University of Science and Technology Thuwal23955-6900 Saudi Arabia

We study the appearance of a boundary condition along an interface between two regions, one with constant diffusivity 1 and the other with diffusivity ϵ > 0, when ϵ → 0. In particular, we take Fick’s diffusion law in a context of reaction-diffusion equation with bistable nonlinearity and show that the limit of the reaction-diffusion equation satisfies the homogeneous Neumann boundary condition along the interface. This problem is developed as an application of heterogeneous diffusion laws to study the geometry effect of *** Codes 35K20, 35K57, 35K60, 82C24 Copyright © 2023, The Authors. All rights reserved.

关键词： Linear equations

Faster Rates of Private Stochastic Convex Optimization

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arXiv 2021年

作者： Su, Jinyan Hu, Lijie Wang, Di School of Mathematical Sciences University of Electronic Science and Technology of China China Division of Computer Electrical and Mathematical Sciences and Engineering King Abdullah University of Science and Technology Saudi Arabia

In this paper, we revisit the problem of Differentially Private Stochastic Convex Optimization (DP-SCO) and provide excess population risks for some special classes of functions that are faster than the previous results of general convex and strongly convex functions. In the first part of the paper, we study the case where the population risk function satisfies the Tysbakov Noise Condition (TNC) with some parameter θ > 1. Specifically, we first show that under some mild assumptions on the loss functions, there is an algorithm whose output could achieve an upper bound of (Equation presented) and (Equation presented) for ∊-DP and (∊, δ)-DP, respectively when θ ≥ 2, here n is the sample size and d is the dimension of the space. Then we address the inefficiency issue, improve the upper bounds by Poly(log n) factors and extend to the case where θ ≥ (Equation presented) > 1 for some known (Equation presented). Next we show that the excess population risk of population functions satisfying TNC with parameter θ ≥ 2 is always lower bounded by (Equation presented) and (Equation presented) for ∊-DP and (∊, δ)-DP, respectively, which matches our upper bounds. In the second part, we focus on a special case where the population risk function is strongly convex. Unlike the previous studies, here we assume the loss function is non-negative and the optimal value of population risk is sufficiently small. With these additional assumptions, we propose a new method whose output could achieve an upper bound of (Equation presented) and (Equation presented) for any τ > 1 in (∊, δ)-DP and ∊-DP model respectively if the sample size n is sufficiently large. These results circumvent their corresponding lower bounds in (Feldman et al., 2020) for general strongly convex functions. Finally, we conduct experiments of our new methods on real world data. Experimental results also provide new insights into established theories. © 2021, CC BY.

关键词： Stochastic systems

Effect of Environment Temperature and Relative Humidity on Thermal Emissivity: Study Case of Mango Fruit

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Effect of Environment Temperature and Relative Humidity on T...

International Symposium on Intelligent Systems and Informatics (SISY)

作者： Panmanas Sirisomboon Jiraporn Sripinyowanich Jongyingcharoen Apiwat Junto Thitima Phanomsophon Cheewanun Dachoupakan Sirisomboon Panan Rerngsamran Dharma Raj Pokhrel Sneha Sharma Jetsada Posom Pimpen Pornchaloempong Anupun Terdwongwarakul Prabhas Chongstitvatana Department of Agricultural Engineering School of Engineering King Mongkut's Institute of Technology Ladkrabang Bangkok Thailand Department of Agricultural Engineering School of Engineering and Innovation Rajamangala University of Technology Tawan-Ok Chon Buri Thailand Office of Administrative Interdisciplinary Program on Agricultural Technology School of Agricultural Technology King Mongkut's Institute of Technology Ladkrabang Bangkok Thailand Department of Microbiology Faculty of Science Chulalongkorn University Bangkok Thailand Department of Infrastructure Engineering University of Melbourne Victoria Australia Department of Agricultural Engineering Faculty of Engineering Khon Kaen University Khon Kaen Thailand Department of Food Engineering School of Engineering King Mongkut's Institute of Technology Ladkrabang Bangkok Thailand Department of Agricultural Engineering Faculty of Engineering at Kanpangsan Kasetsart University Thailand Department of Computer Engineering Chulalongkorn University Bangkok Thailand

ISBN: (数字)9798350385601

ISBN: (纸本)9798350385618

This research was to study the effect of the environment condition during image captured including temperature and relative humidity in the packaging house of the mango exporting factory and in the orchard on the emissivity of mango fruit. The result showed that in the controlled environment of the packaging house in factory, the emissivity was increased (the mango emitted more energy) when the surface temperature was lower and the emissivity of mango is 0.71-0.84 and in the uncontrolled environment of open-air packaging yard in the mango orchard, the different transpiration rates of mango effected mainly by ambient temperature and relative humidity make the morning condition emissivity of 0.44-0.66 and the afternoon condition of 0.72-0.98. There was the effect of the different measured positions on the fruits where the physiology was different and the fluctuated environment in the latter condition made the wide range of emissivity of mangoes. This indicated the shortcoming of thermal imaging of horticultural product if the correct emissivity varied and difficult to set in the thermal camera setting, hence the inaccurate thermogram to be obtained.

关键词： Temperature measurement Transpiration Temperature Humidity Packaging Position measurement Cameras Production facilities Physiology Temperature control

Monitoring Fish Diversity: A Case Study Using Remote Underwater Video Surveys in the Aegean Sea

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Monitoring Fish Diversity: A Case Study Using Remote Underwa...

IEEE International Workshop on Metrology for the Sea;Learning to Measure Sea Health Parameters (MetroSea)

作者： Jude Hamilton Nia Stephens Maurice Calton Seal Anastasia Miliou Laura Macrina School of Biological Sciences Queen's University Belfast Belfast Northem Ireland University of Exeter Penryn Campus Penryn United Kingdom Marine Ecology Supervisor Archipelagos Institute of Marine Conservation Samos Greece Archipelagos Institute of Marine Conservation Samos Greece Marine Science Program Biological and Environmental Science and Engineering Division King Abdullah University of Science and Technology (KAUST) Thuwal Saudi Arabia

ISBN: (数字)9798350379006

ISBN: (纸本)9798350379013

The Mediterranean Sea hosts a plethora of fish species, occupying a wide variety of ecological niches and environments. These crucial habitats, such as seagrass meadows and rocky reefs, are often at high risk of degradation, primarily due to anthropogenic stressors. While biodiversity in the Mediterranean basin is overall well studied, fish assemblages of the North Aegean islands have received less attention to date. Here, we used remote underwater videos (RUV) to assess the richness and abundance of the fish species populating Posidonia oceanica seagrass meadows and rocky reefs around two island in the Aegean Sea, Lipsi and Samos. The results show overlap of niches for most species, while also highlighting the presence of habitat-specific taxa. Six species were found on both islands, in both seagrass and rocky habitats. The presence of three species, namely Diplodus annularis, Labrus viridis, and Sarpa salpa, appeared to be significantly correlated with the habitat type. This study represents a preliminary assessment of fish biodiversity in the Aegean Sea through the use of RUV data. While further data are needed to conclusively evaluate differences between habitat types, this study provides baseline information to establish conservation and management plans.

关键词： Surveys Habitats Sea measurements Metrology Fish Biodiversity Environmental management Monitoring Substrates Videos

The effect of B – site cation on the supercapacitive properties of LaBO3 (B = Cr, Mn, Fe and Co) porous perovskites

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Journal of Energy Storage 2024年 86卷

作者： Ashok C, Shyamli Vazhayil, Ashalatha Vinaykumar, R. Thomas, Jasmine Jeffery, A. Anto Hasan, Imran Thomas, Nygil Yadav, Akhilesh Kumar Ahn, Young-Ho Department of Chemistry Nirmalagiri College Kerala Kannur India Department of Electronics and Communication Engineering Nitte Meenakshi Institute of Technology Karnataka Bangalore5600064 India Environmental Science and Engineering Laboratory Department of Civil Engineering Yeungnam University Gyeongsan38541 Korea Republic of Department of BioEngineering Saveetha School of Engineering Tamil Nadu Chennai602105 India Department of Chemistry College of Science King Saud University Riyadh11451 Saudi Arabia College of Electrical Engineering and Computer Science National Taipei University of Technology Taipei10608 Taiwan Varanasi221005 India

Perovskite oxides have attracted great attention as favorable electrode materials for supercapacitors due to their sole structure, intrinsic oxygen vacancy and compositional flexibility. However, a facile synthetic route which is simple and economical is a challenging issue related to the synthesis of such complex functional oxides. We present a facile and ultrafast way to synthesize LaBO3 (B = Cr, Mn, Fe and Co) perovskite nanocrystallites using glycine-nitrate autocombustion followed by annealing. The structure, phase purity, thermal stability, morphology and surface features of thus synthesized perovskite oxides were analyzed by X-ray diffraction, Fourier transform infrared spectroscopy, Field emission scanning electron microscopy, High resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and Brunauer-Emmet-Teller measurements. The role of B – site cation on the electrochemical performance has been investigated by cyclic voltammetry, galvanostatic charge discharge measurements and electrochemical impedance spectroscopy. Electrochemical measurements showed that, among the synthesized materials, LaBO3 nanoparticles with smallest transition metal cation at its B – site, that is LaCoO3 delivered highest value of specific capacitance (750 F/g) and the value of specific capacitance decreases in the order LaCoO3 ˃ LaMnO3 ˃ LaCrO3 ˃ LaFeO3. Therefore, B – site transition metal cation holds the key to regulate perovskite's properties which are essential prerequisites for supercapacitors. An asymmetric device fabricated using LaCoO3 and activated carbon as the positive and negative electrode respectively acted in broad potential window (1.7 V) and delivered an energy density of 22.2 Wh/kg at a power density of 997.7 W/kg and two supercapacitors connected in series could power a red light emitting diode efficiently. © 2024 Elsevier Ltd

关键词： Supercapacitor

Statistical inference for local granger causality

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arXiv 2021年

作者： Liu, Yan Taniguchi, Masanobu Ombao, Hernando Institute for Mathematical Science Waseda University Institute for Science and Engineering Waseda University Statistics Program King Abdullah University of Science and Technology

Granger causality has been employed to investigate causality relations between components of stationary multiple time series. We generalize this concept by developing statistical inference for local Granger causality for multivariate locally stationary processes. Our proposed local Granger causality approach captures time-evolving causality relationships in nonstationary processes. The proposed local Granger causality is well represented in the frequency domain and estimated based on the parametric time-varying spectral density matrix using the local Whittle likelihood. Under regularity conditions, we demonstrate that the estimators converge to multivariate normal in distribution. Additionally, the test statistic for the local Granger causality is shown to be asymptotically distributed as a quadratic form of a multivariate normal distribution. The finite sample performance is confirmed with several simulation studies for multivariate time-varying autoregressive models. For practical demonstration, the proposed local Granger causality method uncovered new functional connectivity relationships between channels in brain signals. Moreover, the method was able to identify structural changes in financial *** Codes 62M10, 62M15 © 2021, CC BY.

关键词： Statistical tests

A gas-only bioreactor system maintains stable culture environments and reveals that moderate pH deviations trigger transcriptome-wide responses in human cells cultured in physioxia and physiological buffers

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Life Medicine 2023年第2期1卷 236-240页

作者： Silvia Arossa Samhan M. Alsolami Shannon G. Klein Yingzi Zhang Gerardo Ramos-Mandujano Alexandra Steckbauer Anieka J. Parry Juan Carlos Izpisúa-Belmonte Carlos M. Duarte Mo Li Red Sea Research Centre (RSRC) and Computational Bioscience Research Center (CBRC) King Abdullah University of Science and Technology Thuwal 23955 Saudi Arabia Bioscience Program Biological and Environmental Science and Engineering Division (BESE) King Abdullah University of Science and Technology Thuwal 23955 Saudi Arabia Gene Expression Laboratory Salk Institute for Biological Studies 10010 North Torrey Pines Rd. La Jolla CA 92037 USA Altos Labs Inc. 5510 Morehouse Drive Suite 300 San Diego CA 92121 USA

Constrained Wrapped Least Squares: A Tool for High Accuracy GNSS Attitude Determination

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arXiv 2021年

作者： Liu, Xing Ballal, Tarig Chen, Hui Al-Naffouri, Tareq Y. The Division of Computer Electrical and Mathematical Sciences and Engineering King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia The Department of Electrical Engineering Chalmers University of Technology Gothenburg41296 Sweden

Attitude determination is a popular application of Global Navigation Satellite Systems (GNSS). Many methods have been developed to solve the attitude determination problem with different performance offerings. We develop a constrained wrapped least-squares (C-WLS) method for high-accuracy attitude determination. This approach is built on an optimization model that leverages prior information related to the antenna array and the integer nature of the carrier-phase ambiguities in an innovative way. The proposed approach adopts an efficient search strategy to estimate the vehicle’s attitude parameters using ambiguous carrier-phase observations directly, without requiring prior carrier-phase ambiguity fixing. The performance of the proposed method is evaluated via simulations and experimentally utilizing data collected using multiple GNSS receivers. The simulation and experimental results demonstrate excellent performance, with the proposed method outperforming the ambiguity function method, the constrained LAMBDA and multivariate constrained LAMBDA methods, three prominent attitude determination algorithms. Copyright © 2021, The Authors. All rights reserved.

关键词： Global positioning system