bluuebunny/crossref_metadata_2025_split huggingface dataset:
Online parameter adaptive control of mobile robots based on deep reinforcement learning under multiple optimisation objectives
Authors: Sui Xiuli , Chen Haiyong 
Published: August 2024

AbstractFixed control parameters and various optimisation objectives significantly limit the robot control performance. To address such issues, a parameter adaptive controller based on deep reinforcement learning is introduced firstly to adjust control parameters according to the real‐time system state. Further, multiple evaluation mechanisms are constructed to take account of optimisation objectives so that the controller can adapt to different control performance indexes by different evaluation mechanisms. Finally, the target pedestrian tracking control with mobile robots is selected as the validation case study, and the Proportional‐Derivative Controller is chosen as the foundation controller. Several simulation and experimental examples are designed, and the results demonstrate that the proposed method shows satisfactory performance while taking account of multiple optimisation objectives.
Stability of Hemostasis Parameters in Whole Blood, Plasma, and Frozen Plasma: Literature Review and Recommendations of the SFTH (French Society of Thrombosis and Haemostasis)
Authors: Flaujac Claire , Delassasseigne Céline , Hurtaud-Roux Marie-Françoise , Delahousse Benedicte , Boissier Elodie , Desconclois Céline ,   the Working Group on Preanalytics in the French Society of Thrombosis Haemostasis
Published: August 2024

AbstractPreanalytical sample management is critical for a proper assessment of hemostasis parameters, and may differ depending on prescribed tests or additional tests considered to be necessary after initial results. Although there is quite vast literature on this issue, the Working Group of the French Society of Thrombosis and Haemostasis (SFTH) deemed it necessary to make an in-depth literature review and propose recommendations for the proper handling of samples prior to hemostasis assays. This extensive assessment is accessible on-line in French at the SFTH website. Here, a more synthetic view of these recommendations is proposed, supported by easy-to-use tables. The latter respectively deal with the stability of whole blood or fresh plasma, frozen samples, and proper handling of samples forwarded on dry ice. Procedures are classified as recommended, acceptable, not conformed and lacking data. This work involved the retrieval of 125 references, first screened by a working group of 6 experts, then reviewed by 20 other experts in the field. The highly detailed conditions summarized in these tables will hopefully help hemostasis laboratories to secure the conditions recommended for sample collection and transportation. Moreover, as some conditions clearly lacked recommendations, this review can open new fields of investigation for hemostasis preanalytics.
Micromachined Joule–Thomson cooling for long-time and precise thermal management
Authors: Pei Haiyue , Qi Limin , Lu Yihan , Liu Dongli , Zhu Jiakai , Zhao Ding , Qiu Min 
Published: August 2024

Efficient thermal management is essential for low-temperature optoelectronic devices. Traditional liquid nitrogen (LN2) cooling presents challenges such as frequent replenishment needs and limited operational duration. This study introduces micromachined Joule–Thomson (MJT) cooling as a superior alternative for temperature regulation in optoelectronic devices. We evaluated the thermal and optical performance of MJT cooling for a CdSe/ZnS quantum dot (QD) sample within a temperature range of 120–300 K. Thermal analysis showed that with a single 50 l nitrogen refill, the MJT system can operate continuously for over one week, surpassing the LN2 system by 11 times. The temperature stability was affected little by laser irradiation, with a &lt;0.2 K rise at 5 mW of laser power. In addition, the MJT cooling led to an average blueshift of 1–3 meV in the emission peak of QDs and 0.3–2.3 meV reduced spectral broadening compared to LN2, attributed to a smaller sample-to-cold-stage temperature gap of about 8–9 K in the MJT setup. The standard deviations of peak energy and FWHM are in the order of E − 1 meV magnitude, demonstrating a comparable thermal uniformity compared to LN2. The vibration spectra obtained for both vertical and horizontal directions reveal the superior low-vibration characteristics of MJT cooling. These findings validate MJT cooling as a superior and reliable strategy for the thermal management of optoelectronics, ensuring prolonged operational durations, reliable temperature stability, enhanced temperature precision, high thermal homogeneity, and low vibrations.
Heavy ion beam probe for Wendelstein 7-X measurement capabilities as projected through its design
Authors: Demers D. R. , Crowley T. P. , Fimognari P. J. , Mora H. Trimino , Grulke O. , Laube R. 
Published: August 2024

A heavy ion beam probe (HIBP) diagnostic is being developed for studies of plasma equilibrium and turbulence in the optimized Wendelstein 7-X (W7-X) stellarator. Operation of W7-X has experimentally demonstrated that its optimized magnetic field results in improved neoclassical particle confinement and, as a result, turbulence is the predominant cause of energy transport. The HIBP will have the unique ability to provide experimental data needed to complement models of both neoclassical and turbulent transport. It will acquire direct measurements in the W7-X plasma interior of the electric potential (needed for understanding ambipolar particle flux) and fluctuations of electron density and potential (needed for understanding turbulence). The HIBP for W7-X will inject singly charged ion beams with energies of up to 2 MeV and is designed to access the upper cross section of the W7-X plasma. We use trajectory simulations to illustrate the plasma coverage that the diagnostic can achieve in the reference magnetic configurations of W7-X. We calculate beam signal levels, discuss anticipated measurement sensitivity of broadband fluctuations of electron density and plasma potential, and show how they depend on plasma density. We also discuss the diagnostic sensitivity to equilibrium plasma potential.
A bilevel optimization method for inverse mean-field games*
Authors: Yu Jiajia , Xiao Quan , Chen Tianyi , Lai Rongjie 
Published: August 2024

Abstract
In this paper, we introduce a bilevel optimization framework for addressing inverse mean-field games, alongside an exploration of numerical methods tailored for this bilevel problem. The primary benefit of our bilevel formulation lies in maintaining the convexity of the objective function and the linearity of constraints in the forward problem. Our paper focuses on inverse mean-field games characterized by unknown obstacles and metrics. We show numerical stability for these two types of inverse problems. More importantly, we, for the first time, establish the identifiability of the inverse mean-field game with unknown obstacles via the solution of the resultant bilevel problem. The bilevel approach enables us to employ an alternating gradient-based optimization algorithm with a provable convergence guarantee. To validate the effectiveness of our methods in solving the inverse problems, we have designed comprehensive numerical experiments, providing empirical evidence of its efficacy.
Exact recovery of the support of piecewise constant images via total variation regularization
Authors: De Castro Yohann , Duval Vincent , Petit Romain 
Published: August 2024

Abstract
This work is concerned with the recovery of piecewise constant images from noisy linear measurements. We study the noise robustness of a variational reconstruction method, which is based on total (gradient) variation regularization. We show that, if the unknown image is the superposition of a few simple shapes, and if a non-degenerate source condition holds, then, in the low noise regime, the reconstructed images have the same structure: they are the superposition of the same number of shapes, each a smooth deformation of one of the unknown shapes. Moreover, the reconstructed shapes and the associated intensities converge to the unknown ones as the noise goes to zero.
A novel framework for bearing fault diagnosis across working conditions based on time-frequency fusion and multi-sensor data fusion
Authors: Lin Bo , Zhu Guanhua , Zhang Qinghua , Sun Guoxi 
Published: August 2024

Abstract
The condition of bearings significantly impacts the healthy operation of rotating machinery. However, bearings are prone to failure under a harsh working environment and alternating load. Integrating time-domain, frequency-domain, and multi-sensor data information has been a remarkable way to improve the accuracy and robustness of bearing fault diagnosis. How to combine these pieces of information remains a significant challenge. A novel network architecture called time-frequency multi-sensor fusion network is developed to address this issue. Firstly, a multi-scale feature extraction module based on a one-dimensional convolutional neural network is proposed for extracting multi-scale information from time-domain signals. Secondly, a multi-sensor data fusion strategy based on scaled dot product attention is applied to facilitate feature interaction among multi-sensor data. Thirdly, a time-frequency fusion module is designed to fuse the time-domain and frequency-domain features from multi-sensor. Finally, the effectiveness and superiority of the proposed method are validated on the Paderborn dataset.
Anomalous hybridized excitons induced by combined effects of Van der Waals coupling and Rashba spin–orbit coupling
Authors: Tan Fengxue , Liu Fujun , Li Jinhua 
Published: August 2024

Abstract
As a typical transition-metal dichalcogenide, MoS2 has drawn wide attention due to its good stability and excellent physicochemical properties, making it suitable for visible-region optoelectronic devices. To expand its application, bandgap engineering via heterostructure, thus far, was conventionally employed to tune the band gap. However, this strategy has the disadvantage that energy levels of bands do not show obvious changes compared to the isolated components, limiting the range of applications. Here, we achieve hybridized excitons induced by combined effects of Van der Waals (vdW) coupling and Rashba spin–orbit coupling (SOC), with a small exciton energy of 0.65 eV. For this purpose, we design a MoS2/MoWC heterostructure, where a built-in field (due to the absence of mirror symmetry) induces the Rashba SOC and contributes to the anomalous hybridized states, combined with the vdW coupling. An effective model is proposed to demonstrate the anomalous hybridized states for the heterostructure. Our approach reveals a novel mechanics model for hybridized excitons states, providing new physical ways to achieve infrared-region devices.
Contrast and quantum noise in single-exposure dual-energy thoracic imaging with photon-counting x-ray detectors
Authors: Dhari Jeffrey , Tanguay Jesse 
Published: August 2024

Abstract

Objective. Photon-counting x-ray detectors (PCDs) can produce dual-energy (DE) x-ray images of lung cancer in a single x-ray exposure. It is important to understand the factors that affect contrast, noise and the contrast-to-noise ratio (CNR). This study quantifies the dependence of CNR on tube voltage, energy threshold and patient thickness in single exposure, DE, bone-suppressed thoracic imaging with PCDs, and elucidates how the fundamental processes inherent in x-ray detection by PCDs contribute to CNR degradation. Approach. We modeled the DE CNR for five theoretical PCDs, ranging from an ideal PCD that detects every primary photon in the correct energy bin while rejecting all scattered radiation to a non-ideal PCD that suffers from charge-sharing and electronic noise, and detects scatter. CNR was computed as a function of tube voltage and high energy threshold for average and larger-than-average patients. Model predictions were compared with experimental data extracted from images acquired using a cadmium telluride (CdTe) PCD with two energy bins and analog charge summing for charge-sharing suppression. The imaging phantom simulated attenuation, scatter and contrast in lung nodule imaging. We quantified CNR improvements achievable with anti-correlated noise reduction (ACNR) and measured the range of exposure rates over which pulse pile-up is negligible. Main Results. The realistic model predicted overall trends observed in the experimental data. CNR improvements with ACNR were approximately five-fold, and modeled CNR-enhancements were on average within 10% of experiment. CNR increased modestly (i.e.

<

20%) when increasing the tube voltage from 90 kV to 130 kV. Optimal energy thresholds ranged from 50 keV to 70 keV across all tube voltages and patient thicknesses with and without ACNR. Quantum efficiency, electronic noise, charge sharing and scatter degraded CNR by ~50%. Charge sharing and scatter had the largest effect on CNR, degrading it by ~30% and ~15% respectively. Dead-time losses were less than 5% for patient exposure rates within the range of clinical exposure rates. Significance. In this study, we (1) employed analytical and computational models to assess the impact of different factors on CNR in single-exposure DE imaging with PCDs, (2) evaluated the accuracy of these models in predicting experimental trends, (3) quantified improvements in CNR achievable through ACNR and (4) determined the range of patient exposure rates at which pulse pile-up can be considered negligible. To the best of our knowledge, this study represents the first systematic investigation of single-exposure DE imaging of lung nodules with PCDs.
Fractionation dose optimization facilities the implementation of transmission proton FLASH-RT
Authors: Zeng Yiling , Zhang Qi , Pang Bo , Liu Muyu , Chang Yu , Wang Ye , Quan Hong , Yang Zhiyong 
Published: August 2024

Abstract

Objective. The beam switching time and fractional dose influence the FLASH effect. A single-beam-per-fraction (SBPF) scheme using uniform fractional dose (UFD) has been proposed for FLASH- radiotherapy (FLASH-RT) to eliminate the beam switching time. Based on SBPF schemes, a fractionation dose optimization algorithm is proposed to optimize non-UFD plans to maximize the fractionation effect and dose-dependent FLASH effect. Approach. The UFD plan, containing five 236 MeV transmission proton beams, was optimized for 11 patients with peripheral lung cancer, with each beam delivering a uniform dose of 11 Gy to the target. Meanwhile, the non-UFD plan was optimized using fractionation dose optimization. To compare the two plans, the equivalent dose to 2 Gy (EQD2) for the target and normal tissues was calculated with an α/β ratio of 10 and 3, respectively. Both UFD and non-UFD plans ensured that the target received an EQD2 of 96.3 Gy. To investigate the overall improvement in normal tissue sparing with the non-UFD plan, the FLASH-enhanced EQD2 was calculated. Main results. The fractional doses in non-UFD plans ranged between 5.0 Gy and 24.2 Gy. No significant differences were found in EQD22% and EQD298% of targets between UFD and non-UFD plans. However, the D
95% of the target in non-UFD plans was significantly reduced by 15.1%. The sparing effect in non-UFD plans was significantly improved. The FLASH-enhanced EQD2mean in normal tissue and ipsilateral lung was significantly reduced by 3.5% and 10.4%, respectively, in non-UFD plans. The overall improvement is attributed to both the FLASH and fractionation effects. Significance. The fractionation dose optimization can address the limitation of multiple-beam FLASH-RT and utilize the relationship between fractional dose and FLASH effect. Consequently, the non-UFD scheme results in further improvements in normal tissue sparing compared to the UFD scheme, attributed to enhanced fractionation and FLASH effects.
Identifying L-H transition in HL-2A through deep learning
Authors: He Meihuizi , Yang Zongyu , Liu Songfen , Xia Fan , Zhong Wulyu 
Published: August 2024

Abstract
During the operation of tokamak devices, addressing the thermal load issues caused by edge localized modes (ELMs) eruption is crucial. Ideally, mitigation and suppression measures for ELMs should be promptly initiated as soon as the first low-to-high confinement (L-H) transition occurs, which necessitates the real-time monitoring and accurate identification of the L-H transition process. Motivated by this, and by recent deep learning boom, we propose a deep learning-based L-H transition identification algorithm on HL-2A tokamak. In this work, we have constructed a neural network comprising layers of Residual long short-term memory and temporal convolutional network. Unlike previous work based on recognition for ELMs by slice, this method implements recognition on L-H transition process before the first ELMs crash. Therefore the mitigation techniques can be triggered in time to suppress the initial ELMs bursts. In order to further explain the effectiveness of the algorithm, we developed a series of evaluation indicators by shots, and the results show that this algorithm can provide necessary reference for the mitigation and suppression system.
Measurement of small island characteristics using high resolution ECE and CER at DIII-D
Authors: Yang J , Fredrickson E D , Hu Q , Podestà M , Berkery J W , Bardóczi L , La Haye R J , Sauter O , Austin M , Strait E , Chrystal C 
Published: August 2024

Abstract
The measurements using the high resolution electron cyclotron emission radiometry and the charge exchange and recombination spectroscopy are processed using analytic formulas to allow for the detection of islands as small as 1.9 cm. In contrast to large, saturated magnetic islands which are relatively well understood to be governed by the loss of bootstrap current inside the island, small islands are less well understood due to the difficulty of their accurate measurement in tokamaks. Here, ‘small’ islands are islands comparable in size to the ion banana width, which can be as small as 0.8 cm at DIII-D. The new measurement methods allow for the detection of small island widths when the predicted increase of mode frequency to match the Doppler shifted ion diamagnetic frequency is observed. Therefore, for the first time, the mode frequency increase can be unambiguously associated to the acceleration of the magnetic island propagation. Such association allows for a further development and validation of the much-debated theory of ion polarization currents, which is thought to govern the small island growth.
He II line intensity measurements in the JET tokamak
Authors: Lawson K D , Coffey I H , Groth M , Meigs A G , Menmuir S , Thomas B ,   JET Contributors
Published: August 2024

Abstract
An understanding of the behaviour of the D or He fuel used in tokamak discharges is essential in analyses such as modelling edge and divertor transport and the erosion of the vessel walls. However, poor agreement is found between measurements made on the JET tokamak and collisional-radiative models used to predict the hydrogen-like D and He line intensities. The range of temperatures of the plasmas emitting the radiation is also limited, in contrast to that for many impurities for which a wide range is possible. This is particularly so for He II whose line intensities tend to have the same near-constant ratios in most pulses, suggesting that the emission originates in plasma regions with very similar electron temperatures. To gain understanding and to allow quantitative comparisons with theoretical models, extensive observations of the VUV Lyman series have been made, for all discharge scenarios run during three He campaigns. Those for He discharges in both JET ITER-like wall (JET-ILW) and JET C (JET-C) campaigns are presented here. He discharges have the advantage of fewer impurities resulting in less complex spectra than when D is used as the fuel. However, the characteristics of the observed discrepancies are similar in both species, allowing He to be used as a proxy for D in order to gain understanding of the discrepancy. In addition, the study of He avoids the complication of molecular species contributing to the level populations. Opacity effects are also expected to be less severe in He discharges. Nevertheless, so as to ensure that the measurements are not unduly affected by opacity, comparisons have also been made with emission from Balmer and Paschen series members. Measurements of both line intensities and their ratios are presented for all-pulse surveys and for individual pulses. In exceptional cases in which the He emission is intense a dependence on the He II line intensity is demonstrated. The discrepancy between these measurements and the theoretical models is illustrated.
Ground experimental study of the electron density of plasma sheath reduced by pulsed discharge
Authors: Luo Cheng , Zhang Jia , Liu Yanming , Wei Qiang , Dang Mengjia , Ba Yongshan , Gao Jingru , Li Yuxin 
Published: August 2024

Abstract
A plasma sheath will be generated around the hypersonic vehicle during reentry, where a large number of electrons will significantly affect the propagation of EM waves, resulting in the phenomenon of communication blackout. This paper proposes a method of reducing the electron density of reentry vehicle plasma sheath by pulsed discharge. Experiments were conducted in a high-speed plasma wind tunnel to study the effects and scope of pulsed discharge on the plasma sheath electron density using an ultrahigh-speed camera and microwave diagnostic system. The experimental results show that the application of pulsed discharge resulted in the formation of a light intensity attenuation region measuring 14 × 19 × 4 cm around the discharge area, with an attenuation degree ranging from 30% to 58%. The microwave diagnostic results indicate that after the actuator discharge, the electron density of the plasma sheath within a 4 cm height above the vehicle wall is significantly reduced compared to before the actuator discharge, with a maximum reduction of approximately 86%. These results demonstrate that this method has significant effects on reducing plasma sheath electron density. Furthermore, the low power consumption, load, and space requirements suggest that it has potential for practical applications.
Aggregate Cloud Particle Effects in Exoplanet Atmospheres
Authors: Vahidinia Sanaz , Moran Sarah E. , Marley Mark S. , Cuzzi Jeffrey N. 
Published: August 2024

Abstract
Aerosol opacity has emerged as a critical factor controlling transmission and emission spectra. We provide a simple guideline for the effects of aerosol morphology on opacity and residence time in the atmosphere, as it pertains to transit observations, particularly those with flat spectra due to high altitude aerosols. This framework can be used for understanding complex cloud and haze particle properties before getting into detailed microphysical modeling. We consider high altitude aerosols to be composed of large fluffy particles that can have large residence times in the atmosphere and influence the deposition of stellar flux and/or the emergence of thermal emission in a different way than compact droplet particles, as generally modeled to date for extrasolar planetary atmospheres. We demonstrate the important influence of aggregate particle porosity and composition on the extent of the wavelength independent regime. We also consider how such fluffy particles reach such high altitudes and conclude that the most likely scenario is their local production at high altitudes via UV bombardment and subsequent blanketing of the atmosphere, rather than some mechanism of lofting or transport from the lower atmosphere.