Article
Computer Science, Artificial Intelligence
Congliang Chen, Li Shen, Haozhi Huang, Wei Liu
Summary: The article introduces a distributed variant of an adaptive stochastic gradient method for training deep neural networks, incorporating gradient and weight quantization schemes to reduce communication costs and proposing an error-feedback technique to compensate for biases. Theoretical analysis shows convergence to stationary points, and experimental results demonstrate the efficacy of the proposed methods.
ACM TRANSACTIONS ON INTELLIGENT SYSTEMS AND TECHNOLOGY
(2021)
Article
Computer Science, Information Systems
Jingjing Yan, Xiaofan Mao, Yuanqing Xia, Lan Wu
Summary: This paper studies the output feedback stabilization of linear switched systems with quantization and time-delay. By designing a feedback controller based on a state observer, the mismatch between system and controller modes, the difficulty of quantization rules design, and the challenges of state reconstruction are addressed.
INFORMATION SCIENCES
(2022)
Article
Physics, Multidisciplinary
Chong-Sun Chu, Chun-Hei Leung
Summary: A fundamental effect of the QED vacuum in an external electromagnetic field is revealed, showing that the quantized vacuum of electrons becomes spin polarized and results in a vacuum spin current. An experiment is proposed to measure the spin torque exerted by the spin current by observing the twisted angle of the director axis of a nematic liquid crystal.
PHYSICAL REVIEW LETTERS
(2021)
Article
Automation & Control Systems
Shijie Yang, Zuosheng Yin, Chengde Tong, Yi Sui, Ping Zheng
Summary: This article investigates the application of the decoupled active damping current controller in the synchronous frame to solve the resonance issue caused by the paralleling of machine inductances and filter capacitors in the current-source inverter. The impedance analysis reveals that the virtual impedance is not always linearly correlated with the damping gain. A z-domain discrete model is established to emulate the real circumstance and analyze the stable boundaries of controller parameters. The conclusions are validated through frequency responses, root trajectories, and experiments.
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
(2023)
Article
Automation & Control Systems
Mingyuan Zhao, Shiqi Zheng, Choon Ki Ahn, Xiaofeng Zong, Chuan-Ke Zhang
Summary: This study introduces a periodic event-triggered output-feedback control method for nonlinear systems with quantized states and multisource disturbances. A novel PET composite control method is proposed based on a PET extended state observer, which can handle both deterministic and stochastic disturbances, as well as quantization in data transmission. The approach uses a PET extended state observer to estimate states and disturbances simultaneously, considering both static and dynamic event-triggered conditions. Experimentation on a direct current brush motor is conducted to validate the proposed approach.
INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL
(2021)
Article
Automation & Control Systems
Jian Wang
Summary: This article introduces a novel quantizer based on spherical polar coordinates for linear systems with quantized feedback, converting the quadratic stabilization problems into robust control systems problems with finite data rate.
IEEE TRANSACTIONS ON AUTOMATIC CONTROL
(2021)
Article
Computer Science, Artificial Intelligence
Sung Jin Yoo, Bong Seok Park
Summary: This paper presents a distributed quantized state feedback approach for ensuring predesignated formation tracking performance of uncertain multiple nonholonomic mobile robots under a band-limited directed network with signal quantization. The proposed methodology uses nonlinear error functions to construct local quantized state feedback trackers that achieve robust formation tracking performance under quantized communications among robots and unknown nonlinearities of robot dynamics. The local quantized state feedback trackers only require the information of quantized relative positions among robots and do not need any velocity information of neighbor robots. The stability of the proposed formation tracking system is analyzed using the quantization errors of closed-loop signals. The effectiveness of the distributed quantized feedback design is verified through simulation results.
EXPERT SYSTEMS WITH APPLICATIONS
(2022)
Article
Engineering, Multidisciplinary
Mingming Ji, Shengchao Su
Summary: This paper discusses the quantized identification of rational systems using a logarithmic quantizer, dividing the identification procedure into two steps: first identifying the noise-free output of the systems and then identifying the unknown parameter based on input and the estimation of the noise-free output. The analysis shows that the estimators are convergent almost everywhere, as illustrated by a numerical example.
MATHEMATICAL PROBLEMS IN ENGINEERING
(2021)
Article
Physics, Particles & Fields
S. Deser
Summary: Based on the most elementary grounds, even source-free General Relativity must be quantized.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Automation & Control Systems
Xiaowei Yu, Yan Lin
Summary: This paper investigates an adaptive output feedback tracking method for a class of uncertain nonlinear systems with input and output quantization. A new controller structure and observer design are proposed, and dynamic surface control is used to avoid higher-order derivatives of the quantized output signal, leading to the convergence of tracking error to a small residual set by appropriately choosing design parameters.
INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL
(2021)
Article
Computer Science, Information Systems
Huanqing Wang, Peter Xiaoping Liu, Xuejun Xie, Xiaoping Liu, Tasawar Hayat, Fuad E. Alsaadi
Summary: This paper studies the problem of adaptive fuzzy asymptotical quantized tracking control of non-strict-feedback systems with unmodeled dynamics. A systemic fuzzy adaptive control scheme is proposed based on backstepping technique and fuzzy approximation property, ensuring the boundedness of all closed-loop system signals and asymptotical tracking performance. The main contributions include extending quantized control algorithm to nonlinear systems with unmodeled dynamics and non-strict-feedback structure, and independence of the quantized parameter in the tracking control scheme.
INFORMATION SCIENCES
(2021)
Article
Automation & Control Systems
Wei Ren, Junlin Xiong
Summary: This article introduces a new control strategy for addressing the stabilization problem in nonlinear control systems by incorporating a coarse quantizer and a two-stage quantization process. By dividing stages into substages to maximize the utilization of quantization regions, sufficient conditions are established to guarantee system stability.
INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL
(2021)
Article
Automation & Control Systems
Wei Kang, Jun Cheng, Xia Zhou, Jinde Cao, Hailing Wang
Summary: This work investigates the asynchronous quantized control of discrete-time Markovian switching Lur'e systems with an event-triggered mechanism. It employs a hidden Markov model to model the asynchronous controller and quantization effects, deriving sufficient conditions by choosing a proper stochastic Lyapunov functional. A practical example is provided to demonstrate the effectiveness and efficiency of the proposed method.
JOURNAL OF THE FRANKLIN INSTITUTE-ENGINEERING AND APPLIED MATHEMATICS
(2021)
Article
Automation & Control Systems
Jian Wang, He He, Jiafeng Yu
Summary: A coding scheme is proposed to stabilize continuous linear scalar systems under a communication channel with finite data rate, lossy observations, and network-induced delay. Conditions for first moment stability, relation on quantization cell boundaries, packet loss probabilities, and network-induced delay are derived and a numerical method is proposed to search for the infimum of the data rate for stability. Despite different lengths of quantization cells, matrices corresponding to these quantization cells have the same maximum eigenvalue for stability.
JOURNAL OF THE FRANKLIN INSTITUTE-ENGINEERING AND APPLIED MATHEMATICS
(2021)
Article
Automation & Control Systems
Jingjing Yan, Hanbing Xue, Yuanqing Xia, Yingqi Zhang
Summary: The investigation focuses on the mixed time/event-triggered quantized model predictive security control for switched systems with DoS attacks. A unique structure that combines a network loop and a local loop is adopted, along with a coordinated operation sequence of permissible controllers based on the permissible type-switching mechanism. Time-varying uniform quantization and mixed time/event-triggered schemes are designed to handle limited bandwidth and save network communication resources. The introduction of a buffer in the observer allows the updating of observer state with different weighting coefficients when DoS attacks occur.
JOURNAL OF THE FRANKLIN INSTITUTE-ENGINEERING AND APPLIED MATHEMATICS
(2023)
Article
Multidisciplinary Sciences
David Reifert, Martins Kokainis, Andris Ambainis, Vyacheslavs Kashcheyevs, Niels Ubbelohde
Summary: The study introduces and implements a circuit-level benchmark that models fidelity as a random walk of an error syndrome, detected by an accumulating probe. It reveals contributions of correlated noise and limits of achievable fidelity through statistical consistency analysis of the full distribution of error counts. This benchmark aids in a thorough metrology of quantum circuits as clock frequency increases and a memory effect is revealed.
NATURE COMMUNICATIONS
(2021)
Article
Physics, Applied
L. Bockhorn, J. C. Rode, L. Gnoerich, P. Zuo, B. Brechtken, R. J. Haug
Summary: Research on the self-assembly of twisted bilayer graphene formed by cutting and folding processes reveals that structures not only move forward but also rotate during self-assembly, ultimately leading to commensurate interlayer configurations in the final positions.
APPLIED PHYSICS LETTERS
(2021)
Article
Energy & Fuels
Paul Bayerl, Nils Folchert, Johannes Bayer, Marvin Dzinnik, Christina Hollemann, Rolf Brendel, Robby Peibst, Rolf J. Haug
Summary: The electrical current through POLO solar cells is affected by tunneling and nanometer-sized pinholes. Experiments with different contact areas revealed the impact of pinhole density and quantized contact resistances on the number of pinholes, with single-pinhole transport observed for small contacts showing high sensitivity to single charges.
PROGRESS IN PHOTOVOLTAICS
(2021)
Editorial Material
Nanoscience & Nanotechnology
Vyacheslavs Kashcheyevs
NATURE NANOTECHNOLOGY
(2022)
Article
Engineering, Chemical
Zhijun Zhao, Li Ding, Richard Hinterding, Alexander Mundstock, Christopher Belke, Rolf J. Haug, Haihui Wang, Armin Feldhoff
Summary: Well-intergrown ZIF-67 membranes were prepared with the assistance of laminarly stacked MXene films, exhibiting excellent gas separation performance and long-term stability against CO2 and H2O.
JOURNAL OF MEMBRANE SCIENCE
(2022)
Article
Energy & Fuels
R. Peibst, M. Rienaecker, Y. Larionova, N. Folchert, F. Haase, C. Hollemann, S. Wolter, J. Kruegener, P. Bayerl, J. Bayer, M. Dzinnik, R. J. Haug, R. Brendel
Summary: Numerical device simulations were used to study the optimization potential of poly-Si on oxide (POLO)(2) IBC solar cells. The implementation of photonic crystals (PCs) and reducing wafer thickness had limited impact on efficiency due to surface recombination losses. Improved surface passivation through an improved hydrogenation process led to increased efficiency potential.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2022)
Article
Nanoscience & Nanotechnology
Xin Cao, Yiteng Zhang, Chenxi Ma, Yinan Wang, Benedikt Brechtken, Rolf J. Haug, Eddy P. Rugeramigabo, Michael Zopf, Fei Ding
Summary: This study investigates the growth of symmetrical and strain-free telecom wavelength quantum dots using the InAl droplet etching method on InP substrates. The results show that InAl droplets can etch nanoholes on the In0.55Al0.45As surface above a substrate temperature of 415 degrees C, providing potential for lattice-matched InGaAs QDs infilling.
Article
Chemistry, Multidisciplinary
Lars Thole, Christopher Belke, Sonja Locmelis, Peter Behrens, Rolf J. Haug
Summary: This study reports measurements of key properties of the two-dimensional transition metal trichalcogenide ZrSe3, showing its potential for new electronic devices.
Article
Physics, Multidisciplinary
M. Kokainis, K. Prusis, J. Vihrovs, V Kashcheyevs, A. Ambainis
Summary: We demonstrate that discrete time quantum walk on the Boolean hypercube of dimension n exhibits strong dispersion property, making it interesting for algorithmic applications requiring fast dispersion over the state space.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2022)
Article
Physics, Multidisciplinary
Olfa Dani, Robert Hussein, Johannes C. Bayer, Sigmund Kohler, Rolf J. Haug
Summary: This study investigates electron transport through asymmetrically coupled InAs double quantum dots and observes an extremely strong temperature dependence of the coherent current peaks of single-electron tunneling. The broadening of the coherent current peaks up to temperatures of 20K is analyzed experimentally and theoretically, and is found to be able to be modeled with quantum dissipation due to two different bosonic baths.
COMMUNICATIONS PHYSICS
(2022)
Article
Nanoscience & Nanotechnology
Niels Ubbelohde, Lars Freise, Elina Pavlovska, Peter G. Silvestrov, Patrik Recher, Martins Kokainis, Girts Barinovs, Frank Hohls, Thomas Weimann, Klaus Pierz, Vyacheslavs Kashcheyevs
Summary: Coincidence correlations between ballistic on-demand electrons passing through a mesoscopic beam splitter are measured and modelled to reveal signatures of unscreened Coulomb interactions, establishing a platform for quantum nonlinearity.
NATURE NANOTECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
Elina Pavlovska, Peter G. Silvestrov, Patrik Recher, Girts Barinovs, Vyacheslavs Kashcheyevs
Summary: This study investigates collisions between isolated electrons guided along the edges in quantum Hall setups, which mimic the mixing of photons. The researchers use a quadratic two-dimensional saddle point potential for the beam splitter and unscreened Coulomb interaction to model the electronic Hong-Ou-Mandel (HOM) experiment. A universal phase diagram is presented to describe the scattering outcomes of bunching and antibunching, and analytical estimates are given for conditions when classical dynamics dominate over quantum effects.
Article
Materials Science, Multidisciplinary
Frank Hohls, Vyacheslavs Kashcheyevs, Friederike Stein, Tobias Wenz, Bernd Kaestner, Hans W. Schumacher
Summary: Single-electron pumps based on tunable-barrier quantum dots are promising candidates for realizing the unit ampere in the revised International System of Units (SI). They are simple to operate and show high precision at high operation frequencies. By employing a two-gate operation scheme, we verify the prediction of back-tunneling effects and demonstrate control of the back-tunneling error.
Article
Materials Science, Multidisciplinary
Sung Ju Hong, Donglei Wang, Dirk Wulferding, Peter Lemmens, Rolf J. Haug
Summary: The magnetotransport properties of single- and double-rhombohedral trilayer graphene (TLG) are investigated. By folding single TLG, a double TLG with a twist angle of 4° is obtained. Raman spectroscopy confirms the ABC stacking order and interlayer coupling. The Landau fan diagram shows overlapped features of each constituent TLG, suggesting weak interlayer coupling.
