Multiple principal-agent relationships, corporate-control mechanisms and expropriation through related party transactions

Zhiwen Zhu 인하대학교 정석물류통상연구원 2009 인하대학교 정석물류통상연구원 학술대회 Vol.2009 No.10

This study investigated the intermediation of expropriation in the linkage between corporate governance and firm value. We manifested the triple principal-agent relationships among minority shareholders, majority shareholders and the board of directors, and conceptualized the expropriation as rents demanded by majority shareholders to compensate their agency function in a theoretical framework of internal and external corporate-control mechanisms for firms with concentrated ownership structure. By using related party transactions as a direct measure for expropriation and the event study, we corroborated the negative value effect of expropriation in China"s stock markets, and found that the controlling capability of controlling shareholders, ownership balancing, identity of controlling shareholders, stock incentives for the board/executives, and the proportion of tradable shares are significantly associated with expropriation. We also found an interact effect between the proportion of tradable shares ande the controlling shareholders on expropriation.

Identification of flutter derivatives of bridge decks using CFD-based discrete-time aerodynamic models

Zhiwen Zhu,Ming Gu 한국풍공학회 2014 한국풍공학회지 Vol.18 No.3

This paper presents a method to extract flutter derivatives of bridge decks based on acombination of the computational fluid dynamics (CFD), system simulations and system identifications. Theincompressible solver adopts an Arbitrary Lagrangian-Eulerian (ALE) formulation with the finite volumediscretization in space. The imposed sectional motion in heaving or pitching relies on exponential time seriesas input, with aerodynamic forces time histories acting on the section evaluated as output. Systemidentifications are carried out to fit coefficients of the inputs and outputs of ARMA models, as to establishdiscrete-time aerodynamic models. System simulations of the established models are then performed as toobtain the lift and moment exerting on the sections to a sinusoidal displacement. It follows that flutterderivatives are identified. The present approaches are applied to a hexagon thin plate and a real bridge deck. The results are compared to the Theodorsen closed-form solution and those from wind tunnel tests. Satisfactory agreements are observed.

Identification of flutter derivatives of bridge decks using CFD-based discrete-time aerodynamic models

Zhu, Zhiwen,Gu, Ming Techno-Press 2014 Wind and Structures, An International Journal (WAS Vol.18 No.3

This paper presents a method to extract flutter derivatives of bridge decks based on a combination of the computational fluid dynamics (CFD), system simulations and system identifications. The incompressible solver adopts an Arbitrary Lagrangian-Eulerian (ALE) formulation with the finite volume discretization in space. The imposed sectional motion in heaving or pitching relies on exponential time series as input, with aerodynamic forces time histories acting on the section evaluated as output. System identifications are carried out to fit coefficients of the inputs and outputs of ARMA models, as to establish discrete-time aerodynamic models. System simulations of the established models are then performed as to obtain the lift and moment exerting on the sections to a sinusoidal displacement. It follows that flutter derivatives are identified. The present approaches are applied to a hexagon thin plate and a real bridge deck. The results are compared to the Theodorsen closed-form solution and those from wind tunnel tests. Satisfactory agreements are observed.

Simulation of Optimized Evacuation Processes based on Sub-Goal CA Model

Zhiwen Hu,Huaqing Mao,Li Zhu 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.5

With the full swing of computer technology, evacuation models are constructed and simulated via computers to study the various phenomena and behaviors during the evacuation process. They open unique potential opportunity to evaluate the architectural design and provide the decision support for the emergency evacuation plans. This paper details a capacity constrained route planner (CCRP) algorithm, which is used to optimize evacuation path, and the distance map based on sub-goal cellular automata (CA) is also proposed to simulate the evacuation scenarios. Two evacuation scenarios are further discussed, and the experimental results strongly suggested that the sub-goal CA model could simulate the evacuation scenarios and evaluate the emergency evacuation plans effectively and finally help us penetrate to the essence of reality.

Dynamic characteristic parameters identification analysis of a parallel manipulator with flexible links

Chunxia Zhu,Jing Wang,Zhiwen Chen,Bo Liu 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.12

This paper presents dynamic parameters identification analysis of a 3-TPT parallel manipulator with flexible links by means of simulationand experiment. The 3-TPT mechanism is described in detail, and the dynamic equations of the regarded mechanism are derivedanalytically based on the Newton’s second law. The dynamic simulation model of parallel manipulator with flexible links is built by theintegration method of virtual prototyping (VP) and finite element analysis (FEA), which forms the flexible multi-body system of parallelmanipulator. Frequency response curves are obtained by applied force on the simulation model, and the stiffness and damping ratio areidentified, respectively, from the simulation results. The strategy has been experimentally tested on an actual 3-TPT parallel manipulator. The compared results show that the errors are very small and reasonable scope, so it is feasible for the integration method used as referenceand basis for dynamic characteristic. Therefore, the integration simulation method provides a theoretical foundation and referencefor dynamic optimal design of parallel manipulator. These analyses and results provide valuable insight into the design and control of theparallel manipulator with flexible links.

Coronal Three-Dimensional Magnetic Resonance Imaging for Improving Diagnostic Accuracy for Posterior Ligamentous Complex Disruption In a Goat Spine Injury Model

Xuee Zhu,Jichen Wang,Dan Zhou,Chong Feng,Zhiwen Dong,Hanxiao Yu 대한영상의학회 2019 Korean Journal of Radiology Vol.20 No.4

Objective: The purpose of this study was to investigate whether three-dimensional (3D) magnetic resonance imaging could improve diagnostic accuracy for suspected posterior ligamentous complex (PLC) disruption. Materials and Methods: We used 20 freshly harvested goat spine samples with 60 segments and intact surrounding soft tissue. The animals were aged 1–1.5 years and consisted of 8 males and 12 females, which were sexually mature but had not reached adult weights. We created a paraspinal contusion model by percutaneously injecting 10 mL saline into each side of the interspinous ligament (ISL). All segments underwent T2-weighted sagittal and coronal short inversion time inversion recovery (STIR) scans as well as coronal and sagittal 3D proton density-weighted spectrally selective inversion recovery (3D-PDW-SPIR) scans acquired at 1.5T. Following scanning, some ISLs were cut and then the segments were rescanned using the same magnetic resonance (MR) techniques. Two radiologists independently assessed the MR images, and the reliability of ISL tear interpretation was assessed using the kappa coefficient. The chi-square test was used to compare the diagnostic accuracy of images obtained using the different MR techniques. Results: The interobserver reliability for detecting ISL disruption was high for all imaging techniques (0.776–0.949). The sensitivity, specificity, and diagnostic accuracy of the coronal 3D-PDW-SPIR technique for detecting ISL tears were 100, 96.9, and 97.9%, respectively, which were significantly higher than those of the sagittal STIR (p = 0.000), coronal STIR (p = 0.000), and sagittal 3D-PDW-SPIR (p = 0.001) techniques. Conclusion: Compared to other MR methods, coronal 3D-PDW-SPIR provides a more accurate diagnosis of ISL disruption. Adding coronal 3D-PDW-SPIR to a routine MR protocol may help to identify PLC disruptions in cases with nearby contusion.

Apoptosis induced in vivo by new type gosling viral enteritis virus

Shun Chen,Anchun Cheng,Mingshu Wang,Dekang Zhu,Renyong Jia,Qihui Luo,Hengmin Cui,Yi Zhou,Yin Wang,Zhiwen Xu,Zhengli Chen,Xiaoyue Chen,Xiaoyu Wang 대한수의학회 2011 JOURNAL OF VETERINARY SCIENCE Vol.12 No.4

In this study, apoptosis was induced by new type gosling viral enteritis virus (NGVEV) in experimentally infected goslings is reported in detail for the first time. After 3-day-old goslings were orally inoculated with a NGVEV-CN strain suspension, the time course of NGVEV effects on apoptotic morphological changes of the internal tissues was evaluated. These changes were observed by histological analysis with light microscopy and ultrastructural analysis with transmission electron microscopy. DNA fragmentation was assessed with a terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay and DNA ladder analysis. A series of characteristic apoptotic morphological changes including chromatin condensation and margination, cytoplasmic shrinkage, plasma membrane blebbing, and formation of apoptotic bodies were noted. Apoptosis was readily observed in the lymphoid and gastrointestinal organs, and sporadically occurred in other organs after 3 days post-infection (PI). The presence and quantity of TUNEL-positive cells increased with infection time until 9 days PI. DNA extracted from the NGVEV-infected gosling cells displayed characteristic 180~200 bp ladders. Apoptotic cells were ubiquitously distributed, especially among lymphocytes, macrophages, monocytes, and epithelial and intestinal cells. Necrosis was subsequently detected during the late NGVEV-infection phase, which was characterized by cell swelling, plasma membrane collapse, and rapidly lysis. Our results suggested that apoptosis may play an important role in the pathogenesis of NGVE disease.

Computer simulation of the nonlinear static behavior of axially functionally graded microtube with porosity

Li, Xiaohuan,Wang, Tian,Liu, Fang,Zhu, Zhiwen Techno-Press 2021 Advances in nano research Vol.11 No.4

Static analysis of microstructures, including bending and buckling, is widely practiced in the fabrication and creation of applications such as actuation, sensing, and energy recovery. This article aims to inquire about the static behavior of non-uniform and imperfect microtubes through a numerical solution. Based on the modified couple stress theory, the first-order shear deformation theory and Von-Karman nonlinear theory, and employing the energy conservation method, the linear and nonlinear governing equations are derived. The porosity-dependent material in both ceramic and metal phases makes the functionally graded materials which are varied along tube length, moreover, cross-sections are also considered uniform and nonuniform via three valuable functions. Finally, the linear and nonlinear equations are solved utilizing the generalized differential quadrature method (GDQM) coupled with the numerical iteration method.