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Network congestion, Braess paradox and urban expressway system
Baomin Dong 인하대학교 정석물류통상연구원 2009 인하대학교 정석물류통상연구원 학술대회 Vol.2009 No.10
Some paradoxes, such as “the Braess Paradox”, persist in transportation networks, This paper studies the congestion properties in networks constituted by a set of circular and diffusive expressways. We use a model with a single origin/multiple destination (E-net) to depict the evening rush hour, and one destination multiple origin(M-net) to depict the morning rush hour. Some conditions for efficient equilibrium in such model are obtained. Policy recommendations such as capacity constrains/increases of key roads and differential parking charges are given.
Baomin Wang,Chao Gao,Zaixin Wu,Hongqin Liu 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.5
The development of special grease makes it possible for angular contact ball bearings to operate at high speed and temperature; however, as an important performance parameter, friction torque of bearings lubricated with grease is much greater than that of bearings lubricated with oil-air, and heat generation due to frictional loss is also greater, so it is necessary to predict the friction torque occurring in grease lubricated angular contact ball bearings. Based on grey system theory, a new prediction methodology for bearing friction torque is proposed which capitalizes on the notion that the information about friction torque of angular contact ball bearing is generally poor, incomplete and uncertain. A grey prediction model, GM (1, N) model, is presented to predict the friction torque in grease lubricated angular contact ball bearings. Several experiments on the friction torque of grease lubricated angular contact ball bearings were conducted to model and validate the effectiveness of the GM (1, N) model through on-line and off-line approaches. Experimental results show that about 90% of bearing friction torque under varying speed can be predicted in the on-line prediction; above 85% of bearing friction torque under varying speed and different loads can be predicted in the off-line prediction. Comprehensive analysis shows that, the GM (1, N) model performs very well for both modeling data and model validation data under different loads, varying bearing speed and work cycles, the proposed methodology can be used to predict bearing friction torque with good accuracy and robustness.
Performance Comparison Between Hama and Hadoop
Shuo Li,Baomin Xu 보안공학연구지원센터 2015 International Journal of Database Theory and Appli Vol.8 No.3
Massive scientific computations such as matrix, graph and network algorithms are very attractive when they come to modelling real-world data. Apache Hama is a pure BSP (Bulk Synchronous Parallel) distributed computing framework for massive scientific computations. In this paper, our experiments were conducted on a 4-node Hadoop cluster. We implement Monte Carlo algorithm of Pi in Hama and Hadoop under the same software and hardware environment. The experimental results show that Hama can achieve much higher performance than Hadoop in our testbed.
Chenglong Zhu,Baomin Li,Jianwei Xia,Na Zhang,Rui Liu 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.6
In this paper, an adaptive event-triggered asymptotic tracking control problem is addressed for switched nonlinear systems with unknown control directions. In existing control schemes, the proposed controller is not directly aimed at the original system, which affects the control performance. Different from the existing control schemes, based on the original system, an event-triggered control law is constructed in this paper. The proposed event-triggered controller guarantees that the tracking error ς1 asymptotically converges to the origin. Finally, the effectiveness of the proposed controller design scheme is proved by simulation examples.
Task Scheduling Algorithm based-on QoS Constrains in Cloud Computing
Yi Zhang,Baomin Xu 보안공학연구지원센터 2015 International Journal of Grid and Distributed Comp Vol.8 No.6
Based on the study of traditional min-min scheduling algorithm, the paper proposed a min-min task scheduling algorithm based on QOS constraints in cloud computing. According to the vector which is generated by QOS parameters, the algorithm processes the matching of resources and tasks, and then provides users with resources which meet their requirements. Experimental results show that the min-min task scheduling algorithm for cloud computing has better performance in such aspects as task execution time, rate of discarding task and QOS satisfaction compared with traditional min-min scheduling algorithm.
Hao Liu,Baomin Fan,Zining Liu,Xiaoqi Zhao,Biao Yang,Xingwen Zheng,Hua Hao 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.106 No.-
Polyaniline (PANI), poly(N-methylaniline) (PNMA) and poly(N-formylanilide) (PNFA) coatings were fabricatedover mild steel via chronoamperometric strategy in oxalate electrolyte. Scanning electron microscope(SEM), attenuated total reflection infrared spectroscopy (ATR-IR) and X-ray photoelectronspectroscopy (XPS) evidenced the polymerization of monomers. Anticorrosive effects of PANI, PNMAand PNFA coatings for steel substrate were evaluated during long-term immersion in 3.5% NaCl solutionby potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and frequency modulation(EFM). Morphological variation for coated specimens before and after immersion in NaCl solutionwas also monitored by SEM and atomic force microscope (AFM). Differentiated protection capability wereobserved for three coatings following the sequence of PNFA > PNMA > PANI. Through electrochemical andinterfacial analyses, electroactivity and physical barrier were ascertained as the critical factors, especiallythe former one, in the long-term protection capacity. Electroactivity was distinguished by the elevatedapparent current density from non-destructive EFM measurements. Furthermore, electron-donationand -withdrawal effects of N-substituents played an essential role in coating electroactivity. In detail,N-substituents improved the anodic protection and physical barrier of PNMA and PNFA coatings. Particularly, formyl with electron-withdrawal effect reinforced the anodic protection and thus the superiorthe anticorrosion efficiency of PNFA for underlying steel.
A Comprehensive Morphological Hybrid Filter Considering Symmetry Maintained
Yuefeng Lu,Shaofeng Lu,Baomin Han,Jianhua Wu,XiZhi Chang,Chen Feng,Shuo Liu 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.10
In this paper, we present a comprehensive morphological hybrid filter considering symmetry maintained, based on composited the morphological hybrid filters and the generalized morphological hybrid filters. The filter improved filtering performance from two aspects: morphological operate mode and optimization of structure elements. It can eliminate the gray values deviation of the images and have the double advantage of the two-path dual filters. Simulation results show that the new hybrid filter can effectively remove the noise in the image while maintaining the image details. Compared with the other morphological hybrid filters, the images filtered by the new filter may have a higher peak signal-to-noise ratio (PSNR) and a smaller mean square error (MSE).
A new dynamic balancing method of spindle based on the identification energy transfer coefficient
Xialun Yun,Xuesong Mei,Gedong Jiang,Baomin Wang 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.10
A new vector matching balance method (VMBM) based on the identification of energy transfer coefficient of spindle rotor system (ETCSRS) is proposed in this paper. This method only needs to extract the original vibration signal of the spindle to compute the spindle rotor system unbalanced vector, and the calculation accuracy depends on the identification precision of ETCSRS. The initial parameters of bearings were calculated by applying Newton-Raphson algorithm based on the quasi-static mechanics analysis of rolling bearings. Through establishing the FEA model of spindle, the structural parameters of the rotor shaft system are obtained and modified by modal correction method. First, the principle of VMBM is verified on a Bentley rotor test bench at different rotating speeds. Second, the verification experiment of VMBM on a high-speed spindle is carried out. Furthermore, the VMBM has a better performance than the influence coefficient method (ICM). The method proposed in this paper is very suitable for on-line dynamic balancing, since it greatly improves the balance efficiency.
Dong Liu,Tao Sun,Yuqin Hu,Yigang Ding,Baomin Fan,Haitao Wang 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.125 No.-
The controllable adjustment of pore structure is of great significance for the high capacitive performanceof porous carbon materials. In this research, a versatile K2CO3 activation approach is proposed to adjustand control the porosity of sunflower plate-derived hierarchical porous carbon materials (HPC-x) by controllingthe K2CO3/carbons mass ratio. Notably, the variety of pore types, including micropores, mesoporesand macropores, can be detected at different K2CO3/carbons mass ratios (0 4). Impressively,the specific surface area of optimal HPC-2 material is 2526 m2/g. Compare with the other samples(HPC-1, HPC-3 or HPC-4), the HPC-2 possess superior capacitance activity (369.4 F/g at 0.5 A/g). Ontop of that, the energy density of HPC-2 assembled supercapacitors in 1 M Na2SO4 and 6 M KOH solutionscan even reach 32.6 and 7.3 Wh/kg, respectively.