Isolated Noncompaction of Ventricular Myocardium: a Magnetic Resonance Imaging Study of 11 Patients

Hong Yun,Meng-su Zeng,Hang Jin,Shan Yang 대한영상의학회 2011 Korean Journal of Radiology Vol.12 No.6

Objective: To retrospectively summarize the cardiac magnetic resonance imaging (CMRI) findings of isolated noncompaction of ventricular myocardium (INVM). Materials and Methods: Eleven patients (M:F = 9:2; mean age, 35 years) were evaluated. Steady-state free precession (SSFP), fast spin echo (SE) sequence, SSFP cine imaging, and delayed enhanced inversion recovery spoiled gradient echo (IR-SPGR) sequence were used for showing abnormal myocardium, measuring ratio of noncompacted/compacted myocardium layers (NC/C ratio), and detecting myocardial viability. The left ventricle was divided into nine segments and a NC/C ratio > 2.3 in diastole was used as cutoff value in diagnosing left INVM. The right ventricle was assessed qualitatively. Results: Cardiac MRI indicated left INVM in seven patients, right INVM in one patient and biventricle INVM in three patients. Characteristic CMRI changes included prominent trabeculations, deep intertrabecular recesses and an increase in the NC/C ratio. The most frequently involved segments was left ventricular apex. Three patients had abnormal high signals within the trabecular structures on SE T2 weighted image. One ventricular aneurysm and one apical thrombus were also observed. Delayed enhancement was seen in six of nine patients with subendocardial and transmural patterns. Conclusion: There are CMRI features that might be characteristic for INVM. Objective: To retrospectively summarize the cardiac magnetic resonance imaging (CMRI) findings of isolated noncompaction of ventricular myocardium (INVM). Materials and Methods: Eleven patients (M:F = 9:2; mean age, 35 years) were evaluated. Steady-state free precession (SSFP), fast spin echo (SE) sequence, SSFP cine imaging, and delayed enhanced inversion recovery spoiled gradient echo (IR-SPGR) sequence were used for showing abnormal myocardium, measuring ratio of noncompacted/compacted myocardium layers (NC/C ratio), and detecting myocardial viability. The left ventricle was divided into nine segments and a NC/C ratio > 2.3 in diastole was used as cutoff value in diagnosing left INVM. The right ventricle was assessed qualitatively. Results: Cardiac MRI indicated left INVM in seven patients, right INVM in one patient and biventricle INVM in three patients. Characteristic CMRI changes included prominent trabeculations, deep intertrabecular recesses and an increase in the NC/C ratio. The most frequently involved segments was left ventricular apex. Three patients had abnormal high signals within the trabecular structures on SE T2 weighted image. One ventricular aneurysm and one apical thrombus were also observed. Delayed enhancement was seen in six of nine patients with subendocardial and transmural patterns. Conclusion: There are CMRI features that might be characteristic for INVM.

Event-triggered Adaptive Tracking Control for Stochastic Nonlinear Systems With State Constraints

Hongyun Yue,Shaofang Feng 제어·로봇·시스템학회 2024 International Journal of Control, Automation, and Vol.22 No.1

This article studies the problem of dynamic-surface-based event-triggered adaptive tracking control for a class of strictly-feedback stochastic nonlinear systems with state constraints. Firstly, radial basis function neural networks (RBFNNs) are used to approximate unknown nonlinear continuous functions, and barrier Lyapunov functions (BLFs) are used to address state constraint problems. Then, the dynamic surface control (DSC) scheme is applied to solve the “explosion of complexity” issue, and error compensation signals are added to reduce the error caused by the filter to achieve a more effective control performance and optimize the algorithm. In addition, this research also considers the case of systems with relative threshold event-triggered mechanisms to save communication resources, and the existence of the lower bound of the minimum inter-event time is proved to exclude the Zeno behavior. Meanwhile, an adaptive tracking controller with the backstepping control strategy is designed, so that all signals in the closed-loop system are bounded and the tracking error converges to a small residual set of the origin in probability. Finally, the simulation examples are given to demonstrate the effectiveness of the control method.

Motor Model-based Optimal Robust Guaranteed Cost Control for Two-motor Web-winding System

Hongyun Xiong,Yipeng Lv,Bin Cheng,Xiaohong Nian,Xiaoyan Chu 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.11

In this paper, a novel comprehensive model for the two-motor web-winding system is proposed, which combines the classical web-winding system model with the driven-motor model. Based on the proposed model, the state feedback robust control (SFRC) strategy is designed to handle systematic uncertainty and time-varying parameters. And then in order to reduce the control cost of the web-winding system, an optimal robust guaranteed cost control (ORGCC) approach is studied. First, the reference control inputs and error dynamic model are derived based on the proposed comprehensive model. Then, the SFRC strategy and ORGCC approach are designed to calculate control compensation. By regarding some suitable parameters as interval variables, the proposed controllers have good robustness for parameter variations and environmental disturbance. Finally, the simulation results illustrate the effectiveness of the proposed model and control.

Temperature-Dependent Saturation Characteristics of Injection Seeded Fabry–PÉrot Laser Diodes/Reflective Optical Amplifiers

Hongyun Meng,Jung-Hyung Moon,Ki-Man Choi,Chang-Hee Lee IEEE 2010 Journal of Lightwave Technology Vol.28 No.3

<P>In this paper, the temperature dependence of the gain and saturation power of injection seeded Fabry-Perot laser diodes/reflective semiconductor optical amplifiers are analyzed theoretically and experimentally. For a constant gain, the saturation power increases with the ambient temperature. This dependency explains the observed variation in relative intensity noise versus injection power, as a function of temperature.</P>

Advanced Stability Analysis of the Tunnels in Jointed Rock Mass Based on TSP and DEM

Hongyun Fan,Liping Li,Hongliang Liu,Shaoshuai Shi,Jie Hu,Shen Zhou 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.4

The discrete element method (DEM) can analyze the large deformation and large displacement of rock mass effectively, and it is widely used in underground engineering, slope engineering and other fields. However, due to the low accuracy of rock mass structural surface information acquisition, the application of discrete element method in the analysis of jointed rock mass stability is still deviated. In this paper, combined with the advantages of the tunnel seismic prediction (TSP) in obtaining discontinuous geological interface information and the discrete element method in the calculation and analysis of jointed rock mass stability, this paper proposes an advanced analysis method for jointed rock mass stability based on TSP and DEM. Compared to the traditional methods, the analysis results of the jointed rock mass stability are more reliable. Firstly, relying on the advanced detection system – Tunnel Seismic Prediction 203Plus, the unstructured rock mass structure information of the tunnel is obtained, and the spatial attitude of the discontinuous geological interface is further determined. Secondly, based on the Fish programming language, the non-continuous geological interface information can be expressed in the discrete unit software – 3D Distinct Element Code (3DEC). In this way, the excavation calculation model of the tunnels in jointed rock mass can be constructed. Finally, based on the DEM, the excavation of the tunnels in jointed rock mass can be simulated, analyze the stability of surrounding rock during the tunnel excavation process, and realize the stability analysis of surrounding rock stability of jointed rock mass. Based on the Huangjiazhuang Tunnel Project, this paper uses the above method to carry out on-site application. The results show that the location of the dangerous block is predicted to be consistent with the actual exposure of the tunnel surrounding rock based on TSP and DEM, which verify the accuracy and feasibility of this method, and the research results have practical guiding significance for the safe construction of the tunnels in jointed rock mass.

Opportunities and Challenges of HTTP Adaptive Streaming

Hongyun Yang,Xuhui Chen,Zongkai Yang,Xiaoliang Zhu,Yi Chen 보안공학연구지원센터 2014 International Journal of Future Generation Communi Vol.7 No.6

HTTP-based Adaptive Streaming (HAS) has emerged as the prominent technology for the delivery of audiovisual content over the Internet in recent years and has a major impact on network traffic. Although traditional stateful session-based streaming solution based on UDP was used initially for media content delivery, researchers and practitioners soon realize that HAS technology, due to get through firewalls friendly ,transfer NAT easily ,effectively utilize the existing networking infrastructure and provide uninterrupted video streaming service to users with dynamic network conditions and heterogeneous devices, has the potential to improve the Quality of Experiments compared with traditional streaming technologies. Consequently, various HAS media streaming solutions have been proposed and deployed successfully. This paper reviews the state-of-the-art of HAS technology and discoveries achieved by numerous researchers. We describe the basic taxonomy of HTTP adaptive streaming systems and summarize the major issues associated with HAS systems’ design. Then we outline the key challenges and open problems and highlight possible avenues for future directions.

Taxation-based Neighbor Selection for Layered Peer-to-Peer Streaming

Hongyun Yang,Ruimin Hu 보안공학연구지원센터 2013 International Journal of Multimedia and Ubiquitous Vol.8 No.2

Effect of La2O3 promoter on NiO/Al2O3 catalyst in CO methanation

Hongyun Qin,Cuili Guo,Yuanyuan Wu,Juntao Zhang 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.7

A series of NiO/Al2O3 catalysts promoted by different La2O3 contents were prepared by impregnation method. The physicochemical properties of NiO-La2O3/Al2O3 were characterized by N2 adsorption-desorption, X-ray diffraction(XRD), H2 temperature programmed reduction (H2-TPR) and H2 chemisorption. The effect of La2O3 on the activityof NiO/Al2O3 for CO methanation was investigated in a fixed bed reactor. A lifetime test, as well as thermogravimetric(TG) analysis, was performed to investigate the stability performance and anti-carbon deposition of catalysts. Theresults showed that the addition of La2O3 can restrain the growth of NiO particles, increase the H2 uptake and Ni dispersion,and therefore enhance the activity of catalysts. When the La2O3 content was 3 wt%, a CO conversion of 98%and a selectivity to CH4 of 96% were obtained at 400 oC. Furthermore, the catalyst NiO-La2O3/Al2O3 with 3 wt% La2O3content displayed highly stable performance in long-term tests, especially exhibiting good anti-carbon deposition property.

An Efficient Supplier Side Scheduling Algorithm for P2P Live Streaming System

Hongyun Yang,Xiaoliang Zhu,Xuhui Chen 보안공학연구지원센터 2013 International Journal of Multimedia and Ubiquitous Vol.8 No.6

Attachable freezing-delayed surfaces for ultraviolet sensing using GaN photodetector at low temperature in air

So, Hongyun,Park, Woosung Elsevier 2019 APPLIED SURFACE SCIENCE - Vol.473 No.-

<P><B>Abstract</B></P> <P>The enhanced optical sensitivity of gallium nitride (GaN) ultraviolet (UV) photodetectors is demonstrated using attachable and hydrophobic freezing-delayed surfaces. The GaN surface attached to microfabricated surfaces with an array of pyramid structures reduced the surface reflectance compared with that of bare GaN surface (∼43.3% decrease at 365 nm wavelength). In addition, as the operation temperature decreased, the hydrophobic pyramid microstructures prevented rapid frost formation by generating dispersed and small-sized frosts (ice crystals). Consequently, the photodetectors fabricated using hydrophobic surfaces with pyramid microstructures showed higher sensitivity (∼48.5% increase in the temperature range of −14 °C to 0 °C) compared to the photodetectors on bare GaN surfaces, supporting the use of hydrophobic surfaces composed of microstructures for UV sensing with higher sensitivity in low-temperature environments.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Attachable and hydrophobic freezing-delayed surface was employed for photodetectors. </LI> <LI> Pyramid microstructures reduced the surface reflectance of GaN in the UV region. </LI> <LI> Simple textured surface generated dispersed and small-sized frosts on GaN surface. </LI> <LI> Higher sensitivity was achieved at low temperatures compared to the bare design. </LI> </UL> </P>