Optimal charging plan for electric bus considering time-of-day electricity tariff

Purpose: The purpose of this study is to develop an optimization method for charging plans with the implementation of time-of-day (TOD) electricity tariff, to reduce electricity bill. Design/methodology/approach: Two optimization models for charging plans respectively with fixed and stochastic trip travel times are developed, to minimize the electricity costs of daily operation of an electric bus. The charging time is taken as the optimization variable. The TOD electricity tariff is considered, and the energy consumption model is developed based on real operation data. An optimal charging plan provides charging times at bus idle times in operation hours during the whole day (charging time is 0 if the bus is not get charged at idle time) which ensure the regular operation of every trip served by this bus. Findings: The electricity costs of the bus route can be reduced by applying the optimal charging plans. Originality/value: This paper produces a viable option for transit agencies to reduce their operation costs

Altered lumbo-pelvic-hip complex muscle morphometry and contraction change in postpartum pelvic girdle pain and asymptomatic subjects: a cross-sectional study

ObjectiveLumbo-pelvic-hip complex muscle training is considered a crucial component of exercise rehabilitation for postpartum women with pelvic girdle pain (PGP). However, there is a paucity of research evidence regarding the morphological changes and contraction function of these muscles in postpartum women with PGP. Understanding the alterations in lumbo-pelvic-hip complex muscles function associated with PGP, is crucial for tailoring effective rehabilitation strategies and promoting optimal postpartum recovery. Therefore, this study aims to compare the differences in muscle thickness and contraction function of lumbo-pelvic-hip complex muscle between postpartum women with PGP and asymptomatic controls using ultrasound imaging.MethodsOne hundred and fifty postpartum women with PGP and fifty age-matched asymptomatic postpartum women were recruited in this study. Real-time musculoskeletal ultrasound was utilized to measure the resting muscle thickness of nine lumbo-pelvic-hip complex muscles, including the erector spinalis (ES), latissimus dorsi (LD), quadratus lumbalis (QL), gluteus maximus (GMax), gluteus medius (GMed), piriformis (PF), iliacus muscle (IM), rectus femoris (RF), and biceps femoris (BF). The thickness of the GMax, GMed, RF, and BF muscles were measured at maximum contraction to calculate a contraction: rest ratio.ResultsCompared to the asymptomatic women, those with PGP exhibited reduced resting thickness of the ES and GMax muscles bilaterally, as well as increased resting thickness of the right LD and IM muscles. Furthermore, the PGP group demonstrated decreased thickness of the left GMed and right RF muscles at maximum contraction. The contraction ratio was also diminished for the GMax muscles bilaterally, left GMed, and right RF in women with postpartum PGP. Conclusion: Postpartum women with PGP demonstrated reduced thickness, asymmetry, and diminished contractility of the lumbo-pelvic-hip complex muscles. Exercise prescriptions for postpartum women with PGP should incorporate targeted strengthening of the ES, GMax, GMed, and RF muscles.ConclusionPostpartum women with PGP demonstrated reduced thickness, asymmetry, and diminished contractility of the lumbo-pelvic-hip complex muscle. Exercise prescriptions for postpartum women with PGP should incorporate targeted strengthening of the ES, GMax, GMed, and RF muscles

AMD-DBSCAN: An Adaptive Multi-density DBSCAN for datasets of extremely variable density

DBSCAN has been widely used in density-based clustering algorithms. However, with the increasing demand for Multi-density clustering, previous traditional DSBCAN can not have good clustering results on Multi-density datasets. In order to address this problem, an adaptive Multi-density DBSCAN algorithm (AMD-DBSCAN) is proposed in this paper. An improved parameter adaptation method is proposed in AMD-DBSCAN to search for multiple parameter pairs (i.e., Eps and MinPts), which are the key parameters to determine the clustering results and performance, therefore allowing the model to be applied to Multi-density datasets. Moreover, only one hyperparameter is required for AMD-DBSCAN to avoid the complicated repetitive initialization operations. Furthermore, the variance of the number of neighbors (VNN) is proposed to measure the difference in density between each cluster. The experimental results show that our AMD-DBSCAN reduces execution time by an average of 75% due to lower algorithm complexity compared with the traditional adaptive algorithm. In addition, AMD-DBSCAN improves accuracy by 24.7% on average over the state-of-the-art design on Multi-density datasets of extremely variable density, while having no performance loss in Single-density scenarios. Our code and datasets are available at https://github.com/AlexandreWANG915/AMD-DBSCAN.Comment: Accepted at DSAA202

A Heterogeneous Parallel Non-von Neumann Architecture System for Accurate and Efficient Machine Learning Molecular Dynamics

This paper proposes a special-purpose system to achieve high-accuracy and high-efficiency machine learning (ML) molecular dynamics (MD) calculations. The system consists of field programmable gate array (FPGA) and application specific integrated circuit (ASIC) working in heterogeneous parallelization. To be specific, a multiplication-less neural network (NN) is deployed on the non-von Neumann (NvN)-based ASIC (SilTerra 180 nm process) to evaluate atomic forces, which is the most computationally expensive part of MD. All other calculations of MD are done using FPGA (Xilinx XC7Z100). It is shown that, to achieve similar-level accuracy, the proposed NvN-based system based on low-end fabrication technologies (180 nm) is 1.6x faster and 10^2-10^3x more energy efficiency than state-of-the-art vN based MLMD using graphics processing units (GPUs) based on much more advanced technologies (12 nm), indicating superiority of the proposed NvN-based heterogeneous parallel architecture

Comparison of macular retinal thickness measurements using spectral-domain and swept-source optical coherence tomography in healthy eyes

AimThis study compares retinal thickness measurements in healthy eyes using one SD-OCT and two SS-OCT devices to assess differences and consistency for clinical application.MethodsForty-eight eyes with a mean age of 28.15 ± 8.85 years were enrolled. Retinal thickness was measured using Heidelberg Spectralis SD-OCT, Svision VG200 SS-OCT, and TowardPi En Face SS-OCT. Normally distributed data were presented as mean ± SD; non-normal data as median (P25–P75). Intraclass correlation coefficients (ICC) and Bland–Altman analysis were used to assess agreement, with a 7 μm error threshold.ResultsSignificant differences were found between the three devices (p < 0.001). SD-OCT measurements were consistently lower than SS-OCT (p < 0.001), while the two SS-OCT devices showed no significant differences except in the nasal region (p = 0.006). ICC values between SD-OCT and SS-OCT devices were low (0.125–0.532), while SS-OCT devices showed better agreement (ICC: 0.369–0.922). Bland–Altman analysis found only 8.33% of SD-OCT and SS-OCT measurements within the 7 μm error range, compared to 81.25–83.33% for SS-OCT devices.ConclusionThe measurements of macular retinal thickness using SD-OCT and SS-OCT devices showed poor consistency and cannot be used interchangeably. However, measurements obtained from different SS-OCT devices demonstrated good consistency. To enhance the accuracy of results, it is recommended to maintain consistency in the devices used for follow-up examinations in the same patient