Multi-phase magneto-electro-elastic stability of nonlocal curved composite shells

Yu Song,Jiangyang Xu 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.41 No.6

Analysis of nonlinear stability behaviors of composite magneto-electro-elastic (MEE) nano-scale shells have been represented in this reaserch. The shell is assumed to be under a transverse mechanical load. Composite MEE material has been produced form piezoelectric and magnetic ingradients in which the material charactristics may be varied according to the percentages of the ingradients. The governing equations including scale effects have been developed in the framework of nonlocal elasticity. It has been demonstrated that nonlinear stability behaviors of MEE nano-sized shells in electrical-magnetic fields rely on the percentages of the ingradients. Also, the efficacy of nonlocality parameter, magnetic intensities and electrical voltages on stability loads of the nanoshells have been researched.

Institutionalizing Rural Women’s Political Participation in China

Yu Song 숙명여자대학교 아시아여성연구원 2016 Asian Women Vol.32 No.3

Electoral gender quotas have been introduced in many countries around the world. China is no exception. Despite a short democratic election tradition and a long history of patriarchal customs, China is keen to promote its women’s political participation at the grassroots. The author analyses the Chinese government’s motivations for imposing electoral quotas for women’s political participation in village governance. Taking Zhejiang, one of the most developed coastal provinces in China, as an example, the article studies the reserved seats elections for both women representatives in the village assembly and women members in the villagers’ committee. By examining the policies, measures, and implementation of such election practice, the author argues that the current institutional arrangement of rural women’s political participation has on the one hand effectively increased the number of women participating in grassroots polity and helped them to get access to power, but caps women’s number and confines women to gendered working roles on the other. In the long run, however, there are prospects for the improved redistribution of power positions between men and women and the lessened reproduction of gendered roles of women members.

Introduction

Yu Song 숙명여자대학교 아시아여성연구원 2017 Asian Women Vol.33 No.2

DRIVER-IN-THE-LOOP HANDLING STABILITY CONTROL OF 4WID-EV

Yu Song,Jun Liu,Huajian Weng,Yaozhong Hu,He Huang 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.2

An eight-degree-of-freedom vehicle dynamic model with electromechanical coupling was established for a four-wheel-independent-drive electric vehicle (4WID-EV). Based on the single-point preview optimal curvature theory, an adaptive fuzzy PID driver model with lateral acceleration feedback was designed, and the control of vehicle trajectory tracking was achieved in the driver-vehicle-road closed-loop coupling model. With the sideslip angle and yaw rate as control variables, the upper layer of a fuzzy sliding mode controller and the lower layer of an optimal distribution controller of the yaw moment were designed. The optimal longitudinal forces of four driving wheels were determined to achieve vehiclehandling stability. J-turn, fishhook, and snake-shaped pile simulations were carried out in MATLAB/Simulink. The results showed that the fuzzy sliding mode controller significantly improved the driving stability of the system, and it had a better anti-chattering ability than the sliding mode control strategy. The established lateral acceleration feedback adaptive fuzzy PID driver model had good trajectory tracking ability. Integration of the two controllers can better achieve both trajectory tracking and driving stability of a 4WID-EV.

Rock bridge fracture model and stability analysis of surrounding rock in underground cavern group

Yu, Song,Zhu, Wei-Shen,Yang, Wei-Min,Zhang, Dun-Fu,Ma, Qing-Song Techno-Press 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.53 No.3

Many hydropower stations in southwest China are located in regions of brittle rock mass with high geo-stresses. Under these conditions deep fractured zones often occur in the sidewalls of the underground caverns of a power station. The theory and methods of fracture and damage mechanics are therefore adopted to study the phenomena. First a flexibility matrix is developed to describe initial geometric imperfections of a jointed rock mass. This model takes into account the area and orientation of the fractured surfaces of multiple joint sets, as well as spacing and density of joints. Using the assumption of the equivalent strain principle, a damage constitutive model is established based on the brittle fracture criterion. In addition the theory of fracture mechanics is applied to analyze the occurrence of secondary cracks during a cavern excavation. The failure criterion, for rock bridge coalescence and the damage evolution equation, has been derived and a new sub-program integrated into the FLAC-3D software. The model has then been applied to the stability analysis of an underground cavern group of a hydropower station in Sichuan province, China. The results of this method are compared with those obtained by using a conventional elasto-plastic model and splitting depth calculated by the splitting failure criterion proposed in a previous study. The results are also compared with the depth of the relaxation and fracture zone in the surrounding rock measured by field monitoring. The distribution of the splitting zone obtained both by the proposed model and by the field monitoring measurements are consistent to the validity of the theory developed herein.

Research on User-personalized Image Retrieval Method

Yu Song,Jing-fei Ren,Mao-Zhu Jin,Pei-Yu Ren 보안공학연구지원센터 2014 International Journal of Multimedia and Ubiquitous Vol.9 No.6

Mitochondrial quality control in intervertebral disc degeneration

Yu Song,Saideng Lu,Wen Geng,Xiaobo Feng,Rongjin Luo,Gaocai Li,Cao Yang 생화학분자생물학회 2021 Experimental and molecular medicine Vol.53 No.-

Intervertebral disc degeneration (IDD) is a common and early-onset pathogenesis in the human lifespan that can increase the risk of low back pain. More clarification of the molecular mechanisms associated with the onset and progression of IDD is likely to help establish novel preventive and therapeutic strategies. Recently, mitochondria have been increasingly recognized as participants in regulating glycolytic metabolism, which has historically been regarded as the main metabolic pathway in intervertebral discs due to their avascular properties. Indeed, mitochondrial structural and functional disruption has been observed in degenerated nucleus pulposus (NP) cells and intervertebral discs. Multilevel and well-orchestrated strategies, namely, mitochondrial quality control (MQC), are involved in the maintenance of mitochondrial integrity, mitochondrial proteostasis, the mitochondrial antioxidant system, mitochondrial dynamics, mitophagy, and mitochondrial biogenesis. Here, we address the key evidence and current knowledge of the role of mitochondrial function in the IDD process and consider how MQC strategies contribute to the protective and detrimental properties of mitochondria in NP cell function. The relevant potential therapeutic treatments targeting MQC for IDD intervention are also summarized. Further clarification of the functional and synergistic mechanisms among MQC mechanisms may provide useful clues for use in developing novel IDD treatments.

Adaptive Range-Based Collision Avoidance MAC Protocol in Wireless Full-duplex Ad Hoc Networks

( Yu Song ),( Wangdong Qi ),( Wenchi Cheng ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.6

Full-duplex (FD) technologies enable wireless nodes to simultaneously transmit and receive signal using the same frequency-band. The FD modes could improve their physical layer throughputs. However, in the wireless ad hoc networks, the FD communications also produce new interference risks. On the one hand, the interference ranges (IRs) of the nodes are enlarged when they work in the FD mode. On the other hand, for each FD pair, the FD communication may cause the potential hidden terminal problems to appear around the both sides. In this paper, to avoid the interference risks, we first model the IR of each node when it works in the FD mode, and then analyze the conditions to be satisfied among the transmission ranges (TRs), carrier-sensing ranges (CSRs), and IRs of the FD pair. Furthermore, in the media access control (MAC) layer, we propose a specific method and protocol for collision avoidance. Based on the modified Omnet++ simulator, we conduct the simulations to validate and evaluate the proposed FD MAC protocol, showing that it can reduce the collisions effectively. When the hidden terminal problem is serious, compared with the existing typical FD MAC protocol, our protocol can increase the system throughput by 80%~90%.

Henry Thoreau in His Beanfield: His Idea of Husbandry

( Yusong Sohn ) 대한영어영문학회 2004 영어영문학연구 Vol.30 No.3

When Henry Thoreau moved to Walden Pond, what he had in mind was to contrive an economy of living for his own use. In carving a niche in the woods he had the advantage of distance enough to take a more critical look at his own self as well as others. He initiated his beanfield as part of his inward-looking effort at self-cultivation. This bean-raising project afforded him the opportunity to get more acquainted with the soil. His farm work helped him to feed his hunger for wildness and practice the transcendental ideal of self-reliance. His beanfield set Thoreau up as a husbandman, whose concern was more with the process than with the result. He appeared more interested in coming by 'intangible' profits: what figured highest in his harvest were seeds of a different kind than beans. Thus he identified himself as a tiller of the mind, rather than as a cultivator of the soil. This difference seems sufficient to characterize his idea of husbandry: it is based on Jeffersonian agrarianism, but more pastoral than practical in that his vision tends toward spirituality. This is how Thoreau stood in his beanfield with the purpose of achieving inner wealth. < Korea University >

DEM Analysis of Fabric Evolution and Behavior of Granular Geomaterials in True Triaxial Test with Flexible Boundary

Yusong Han,Shoji Kato,김병수 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.8

The fabric of granular geomaterials used in roads and embankments is related to properties such as shear strength, permeability and liquefaction resistance. To evaluate the fabric evolution and behavior of geomaterials, a series of the true triaxial test simulations with flexible boundaries under general stress states in this study were performed using the three-dimensional discrete element method (DEM). First, the stress states at the axial strain of 20%, which indicates that the stress under the critical state conforms to the Matsuoka-Nakai criterion, were examined. Then the uniqueness of the coordination number and non-uniqueness of void ratio and invariant of anisotropic fabric tensor under the critical state were investigated based on the contact density, which indicates the relative number of contacts in different orientations. In particular, the contact density at the critical state under different mean effective principal stresses with its effects on the invariant of anisotropic fabric tensor were discussed. It was found that the contribution of the contact density to the fabric anisotropy decreased as the mean effective principal stress increased due to geometric limitations.