Time-frequency warped waveform is a novel type of well-contained waveform composed of raised cosine (RC) pulses with roll-off factors profile customized for spectrally efficient signal containment. The waveform is sui...
Time-frequency warped waveform is a novel type of well-contained waveform composed of raised cosine (RC) pulses with roll-off factors profile customized for spectrally efficient signal containment. The waveform is suited for massive machine-type communication (mMTC), and Internet-of-Things (IoT) applications. The paper is a follow-up to the original work of time-frequency warped waveforms; here, we are proposing a warping function suited for length-independent symbols, which is missing from the previous work. The paper proposes the design steps starting from a piecewise warping function with parts of straight segments and other curved parts. A maximum Out-of-band leakage is used as a criterion to determine the warping function parameters. The roll-off factors profile determined in the previous study is used as a minimum bound for the leakage limits. Gains are presented over Windowed Zero-tail Discrete Fourier Transform-spread-Orthogonal Frequency Division Multiplexing (ZT-DFT-s-OFDM) in the simulations section.
This paper introduces a digitally controlled multiphase multistage hybrid boost converter (MMHBC) for high voltage capacitor charging applications. Rapid capacitor charging control approach is presented, and topologic...
This paper introduces a digitally controlled multiphase multistage hybrid boost converter (MMHBC) for high voltage capacitor charging applications. Rapid capacitor charging control approach is presented, and topological variations to improve efficiency are examined. The controller provides tight output current regulation, while maintaining real-time current balancing capabilities for superior thermal distribution and converter efficiency. The MMHBC is capable of rapid capacitor bank charging to high voltage by forcing maximum output current at the first stage, which translates into maximal output power during the whole charging period. The controller includes a system governor unit which facilitates additional control aspects for multiphase operation such as phase shedding, soft-start mechanism, and system protection. SMPS operation, rapid capacitor charging, and topological improvements are validated experimentally on a four-phase 12V-to-300V multiphase prototype with a maximum output power of 250W and power density of 2.5kW/Liter.
Maintaining system frequency at a rated value is a fundamental requirement to ensure the stability and security of power grids. However, the advanced frequency regulation process is more cyber-dependent, and raises a ...
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Maintaining system frequency at a rated value is a fundamental requirement to ensure the stability and security of power grids. However, the advanced frequency regulation process is more cyber-dependent, and raises a cyber-security issue for the power system. Traditional methods cannot avoid the adverse impacts of cyber attacks, which may lead to frequency deviations and, in severe cases, even blackouts. To address this issue, we propose an attack-resilient control algorithm for the smart grid's frequency regulation to defend the system frequency against cyber attacks. The stability of the system with the proposed controller can be guaranteed, which is strictly proved by Lyapunov theorem. Furthermore, the effectiveness of the proposed resilient controller is validated by case studies. The results show that in comparison with the existing methods, the proposed controller can make the system frequency achieve faster recovery with a minor frequency deviation. Specifically, using the proposed method, the maximum frequency deviation can be reduced from 0.17 Hz to approximately 0 Hz even under a cyber attack, which means that the adverse effects of a cyber attack can be almost eliminated. Therefore, the proposed controller can well counter potential cyber attacks, which helps improve the stability of the system frequency.
This paper introduces a quadrotor's autonomous take-off and landing system on a moving platform. The designed system addresses three challenging problems: fast pose estimation, restricted external localization, an...
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Model predictive control (MPC) has recently been considered for many permanent magnet synchronous machine (PMSM) drive applications. However, the conventional MPC lacks accurate current tracking and fast dynamic respo...
Model predictive control (MPC) has recently been considered for many permanent magnet synchronous machine (PMSM) drive applications. However, the conventional MPC lacks accurate current tracking and fast dynamic responses in the overmodulation region and the six-step operation, which limits its application areas. This paper proposes a six-step operation scheme based on MPC for PMSM drives in traction applications. The current trajectory long-horizon prediction and the average current-based objective function are introduced to determine the optimal switching instants. To enhance the method’s precision, a trapezoidal integration rule has been used in the prediction step. The voltage angle control principle is introduced to clamp the voltage vectors. The effectiveness of the proposed method has been validated by detailed studies. The proposed method is demonstrated to have excellent current tracking accuracy and fast dynamic response in six-step operation, which is an advantage over existing methods.
This paper demonstrates a high-sensitivity substrate-integrated waveguide (SIW) microwave sensor for traditional Chinese medicine decoctions detection. The designed microwave sensor is based on elliptical electric-LC(...
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ISBN:
(数字)9798331541095
ISBN:
(纸本)9798331541101
This paper demonstrates a high-sensitivity substrate-integrated waveguide (SIW) microwave sensor for traditional Chinese medicine decoctions detection. The designed microwave sensor is based on elliptical electric-LC(EELC) and interdigital capacitors (IDC). The regent under test (RUT) with different permittivities from 2 to 5 and dimensions of 9 mm $\times 11$ mm $\times 0.8$ mm is placed on the sensitive area of the sensor. According to the simulated result, the resonant frequency of the sensor shifts between 4.06 and 5.63 GHz with the variation of the RUT permittivity. The designed sensor can achieve sensitivity up to 8.28%, which shows a good feasibility in detecting liquid dielectric properties.
We introduce Autoregressive Graphical Models (AGMs) as an Ansatz for modeling the ground states of stoquastic Hamiltonians. Exact learning of these models for smaller systems show the dominance of the pairwise terms i...
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Data association plays an important role in forming target tracks when false alarms exist. Its accuracy is key to reducing the computational burden of the combinatorial explosion problem inherent to target tracking in...
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Seismic full waveform inversion (FWI) is a widely used technique in geophysics for inferring subsurface structures from seismic data. And InversionNet is one of the most successful data-driven machine learning models ...
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This paper studies distributed online learning under Byzantine attacks. The performance of an online learning algorithm is often characterized by (adversarial) regret, which evaluates the quality of one-step-ahead dec...
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