A comparative study to measure the sagittal condylar inclination using mechanical articulator, virtual articulator and jaw tracking device

Liya Ma,Fei Liu,Jiansong Mei,Jiarui Chao,Zhenyu Wang,Jiefei Shen 대한치과보철학회 2023 The Journal of Advanced Prosthodontics Vol.15 No.1

Purpose. To compare the sagittal condylar inclination (SCI) in dentate individuals measured by the different methods with mechanical articulator (MA), virtual articulator (VA), and a jaw tracking device (JTD) system. Materials and methods. A total of 22 healthy dentate participants were enrolled in this study. For MA workflow, the SCI was obtained by a semi-adjustable articulator with protrusive interocclusal records. The SCI was also set on a VA by aligning intraoral scan (IOS) with cone beam computed tomography (CBCT) and facial scan (FS), respectively. These virtual workflows were conducted in a dental design software, namely VAIOS-CBCT and VAIOS-FS. Meanwhile, a JTD system was also utilized to perform the measurement. Intraclass correlation was used to assess the repeatability within workflows. The bilateral SCI values were compared by Wilcoxon matched-pairs signed rank test for each workflow, and Kruskal-Wallis test and post hoc p-value Bonferroni correction were used to compare the differences among four workflows. The agreement of VAIOS-CBCT, VAIOS-FS, and JTD compared with MA was evaluated by Bland-Altman analysis. Results. Intraclass correlation of the SCI revealed a high degree of repeatability for each workflow. There were no significant differences between the left and right sides (P > .05), except for VAIOS-CBCT (P = .028). Significant differences were not found between MA and VAIOS-FS (P > .05). Bland-Altman plots indicated VAIOS-CBCT, VAIOS-FS, and JTD were considered to substitute MA with high 95% limits of agreement. Conclusion. The workflow of VAIOS-FS provided an alternative approach to measure the SCI compared with MA.

REGENERATIVE BRAKING CONTROL STRATEGY BASED ON MULTI-SOURCE INFORMATION FUSION UNDER ENVIRONMENT PERCEPTION

Chao Ma 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.3

In this paper, regenerative braking control of electric vehicles is investigated based on multi-source information such as image recognition, GPS and vehicle running parameters. Firstly, the fast normalized cross-correlation (FNCC) algorithm is applied to identify the speed limit traffic signs. Then the vehicle speed is intelligently controlled under the fusion of the detected traffic signs and road slope prediction information. Secondly, an adaptive regenerative braking energy recovery strategy based on multi-source information fusion is designed. The adaptive control strategy can automatically adjust under different braking conditions, so the motor can work at the high-efficiency points. The adaptive control strategy provides the possibility to realize the efficient recovery of braking energy. Finally, the effectiveness of the strategy is verified by MATLAB/ Simulink and Prescan co-simulation. Specially, a regenerative braking proportional coefficient K under the multi-source information fusion is proposed. The K can optimize the braking torque distribution and improve the motor high-efficiency operating range. Compared with the traditional series control strategy and fuzzy control strategy, the adaptive control strategy improves the energy recovery rate by 11.9 % and 5.3 % respectively.

Carrageenan Oligosaccharides Extend Life Span and Health Span in Male Drosophila Melanogaster by Modulating Antioxidant Activity, Immunity, and Gut Microbiota

Chao Ma,Qiaowei Li,Xianjun Dai 한국식품영양과학회 2021 Journal of medicinal food Vol.24 No.1

Carrageenan oligosaccharide (CAO), the hydrolysate of carrageenan from marine red algae, is used as a prebiotic additive or medical material. In this study, male Drosophila melanogaster was used as an animal model to explore the possibility that CAO can extend the life span through its relationship with antioxidation, immunity, and gut microbiota in vivo. The results show that a certain amount of CAO effectively prolonged the average life span and improved the climbing vitality and fecundity of male Drosophila. In addition, 0.125% CAO in the diet significantly increased the activity of Cu,Zn-superoxide dismutase (Cu,Zn-SOD) and catalase (CAT), reduced the content of malondialdehyde (MDA), and significantly repressed the expression of nuclear factor kappa B (NF-κB) gene in old male Drosophila tissues. In the intestinal microbiota analysis, 0.125% CAO in the diet increased the diversity of gut microbiota and improved the abundance of Commensalibacter at the genus level in Drosophila on the 40th day. The above results indicated that CAO supplementation could extend the life span of male Drosophila by improving antioxidant activity, immunity, and by regulating intestinal microflora.

A Study on the Design Principle of Battery Capacity for x-EVs

Chao Ma,Minseok Song,Kiyun Jeong,Hyunsoo Kim 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11

A Study on Real Time Based Equivalent Fuel Economy Calculation Algorithm for Green Car

Chao Ma(마차오),Jinhyun Park(박진현),Sung-ho Hwang(황성호),Hyunsoo Kim(김현수) 한국자동차공학회 2012 한국자동차공학회 부문종합 학술대회 Vol.2012 No.5

In this paper, a real time based equivalent fuel economy (EFE) calculation algorithm is presented for green car which consists of the conventional engine, motor and battery. The real time based EFE algorithm calculates the equivalent fuel economy using the parameters directly received from the engine, motor and battery. It is expected that the real time based algorithm can be used for estimation of the fuel economy in real time driving, and on-line virtual interface driving environment as well as off-line evaluation environment for the development and evaluation of the green car.

Development of HEV Simulator for Module Design

Chao Ma,Jian Ji,Sungmin Kim,Hyunsoo Kim 한국자동차공학회 2010 한국자동차공학회 부문종합 학술대회 Vol.2010 No.5

Hybrid electric vehicle (HEV) simulator is developed to evaluate the performance of the HEV sub-modules. First, dynamic model of the HEV powertrain is constructed by using Cruise for Toyota Prius. For the simulation, control algorithms are developed by using MATLAB/Simulink. Using the Cruise simulator and MATLAB/Simulink control algorithms, cosimulation environment is developed. In addition, a graphical user interface (GUI) is developed for sub-modules of the HEV by using MATLAB/GUIDE. The component performance such as power flow, power loss is investigated in the GUI environment. It is expected that co-simulator developed in this study can be used in design of the sub-modules for HEV.

A Study on Control Algorithm and Energy Management Strategy for GM-Volt Plug-in HEV

Chao Ma,Jian Ji,Woulsun Choi,Hyunsoo Kim 한국자동차공학회 2011 한국자동차공학회 학술대회 및 전시회 Vol.2011 No.11

In this paper, a study was performed on the control algorithm and energy management strategy for plug-in HEV. GM-Volt plug-in HEV was selected as the target vehicle, which is capable of driving in Charge depleting (CD) mode with only motor working and Charging sustaining (CS) mode with engine and motor working together. First, powertrain model of GM-Volt was derived. Based on the dynamic model, detailed component control algorithms for CD mode and CS mode were developed. In addition, an energy management strategy was developed from the viewpoint of fuel economy, using the battery state of charge. Drive mode determination algorithm in CD mode was also developed based on the vehicle velocity and wheel torque. Using the dynamic model of and control algorithm for GMVolt plug-in HEV, simulations were performed. Based on the simulation results, an analysis was performed, and it was found that the electric drive range and fuel economy were different with the official values. It was considered due to the transmission loss such as clutch/brake loss and oil pump loss that were not considered in this study.

Development of Control Strategy and Energy Management for Plug-in HEV

Chao Ma,Jian Ji(지건),Hyunsoo Kim(김현수) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5

Plug-in Hybrid Electric Vehicle (PHEV) is considered as the next design objective of hybrid electric vehicle (HEV). It combines the advantages of electric vehicle (EV) and HEV. PHEV has full electric drive mode which can be applied in relative short distance and HEV mode which can be used for long distance. In this paper, the powertrain model of the PHEV is obtained. Based on the analysis of the powertrain model, the control strategy and energy management strategy of PHEV are developed. The PHEV simulator is constructed MATLAB/Simulink. Using the powertrain model and the control strategies, simulations are performed and the simulation results are analyzed. Finally, the plug-in Prius simulator is validated by using the PSAT. It is expected that the PHEV performance can be used for the designers to develop a PHEV.

Robust Stability Analysis of Time-varying Delay Systems via an Augmented States Approach

Chao-Yang Dong,Ming-Yu Ma,Qing Wang,Si-Qian Ma 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.4

This paper focuses on the robust stability analysis of linear systems with time varying delays. The second derivative of the state is used to construct a novel Lyapunov-Krasovskii functional (LKF). Then, both the integrals and derivatives of the states along with the delayed states could be taken into consideration in handling of the LKF. We introduce these augmented variables and establish correlations between them. Moreover, our approach makes it available that quadratic convex combination can be applied not only to the time delay, but also to the derivative of it. Robust stability criteria are presented, and numerical examples illustrate that the methods are less conservative.

Radian of the vault influencing the seismic performances of straight wall arch underground structures

Chao Ma,Dechun Lu,Chengzhi Qi,Xiuli Du 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.78 No.5

Great efforts have been conducted to investigate the seismic performances of the arch and rectangular underground structures, however, the differences between seismic responses of these two types of underground structures, especially the vault radian influencing the seismic responses of arch structures are not clarified. This paper presents a detailed numerical investigation on the seismic responses of arch underground structures with different vault radians, and aims to illustrate the rule that vault radian affects the seismic responses of underground structures. Five arch underground structures are built for nonlinear soil-structure interaction analysis. The internal forces of the structural components of the underground structures only under gravity are discussed detailedly, and an optimum vault radian for perfect load-carrying functionality of arch underground structures is suggested. Then the structures are analyzed under seven scaled ground motions, amounting to a total of 35 dynamic calculations. The numerical results show that the vault radian can have beneficial effects on the seismic response of the arch structure, compared to the rectangular underground structures, causing the central columns to suffer smaller axial force and horizontal deformation. The conclusions provide some directive suggestions for the seismic design of the arch underground structures.