Stochastic Channel Modeling for Railway Tunnel Scenarios at 25 GHz

Danping He,Bo Ai,Ke Guan,Zhangdui Zhong,Bing Hui,김준형,HeeSangChung,김일규 한국전자통신연구원 2018 ETRI Journal Vol.40 No.1

More people prefer using rail traffic for travel or for commuting owing to its convenience and flexibility. The railway scenario has become an important communication scenario in the fifth generation era. The communication system should be designed to support high-data-rate demands with seamless connectivity at a high mobility. In this paper, the channel characteristics are studied and modeled for the railway tunnel scenario with straight and curved route shapes. On the basis of measurements using the “Mobile Hotspot Network” system, a three-dimensional ray tracer (RT) is calibrated and validated for the target scenarios. More channel characteristics are explored via RT simulations at 25.25 GHz with a 500-MHz bandwidth. The key channel parameters are extracted, provided, and incorporated into a 3rd-Generation-Partnership-Project-like stochastic channel generator. The necessary channel information can be practically realized, which can support the link-level and system-level design of the communication system in similar scenarios.

Book Review: English Language Education Policy in Asia

Danping Wang 아시아테플 2016 The Journal of Asia TEFL Vol.13 No.2

The Improvement of Mean-Shift Algorithm in Target Tracking

Danping Jia,Lifeng Zhang,Chunhua Li 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.2

The bandwidth of kernel function is invariance in Mean-Shift tracking process which led to the problem of actual process of tracking failure. To solve this question a method is proposed to combine object contour, RGB color histogram and Mean-Shift tracking algorithm. In each frame the contour and color feature of target object are extracted to as a model. Meanwhile the size of contour is used as the bandwidth for kernel function in the next frame. Based on this Method the accuracy of Mean-Shift tracking is improved and the error of Mean-Shift tracking is reduced.

고속 슬랜트 부호화

쉬단핑(Danping Xu),이문호(Moon Ho Lee),박대철(Daechul Park) 대한전자공학회 2010 대한전자공학회 학술대회 Vol.2010 No.10

Cutting zone area and chip morphology in high-speed cutting of titanium alloy Ti-6Al-4V

Qingchan Ke,Daochun Xu,Danping Xiong 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.1

The titanium alloy Ti-6Al-4V has superior properties but poor machinability, yet is widely used in aerospace and biomedical industries. Chip formation and cutting zone area are important factors that have received limited attention. Thus, we propose a high-speed orthogonal cutting model for serrated chip formation. The high speed orthogonal cutting of Ti-6Al-4V was studied with a cutting speed of 10-160 m/min and a feed of 0.07- 0.11 mm/r. Using theoretical models and experimental results, parameters such as chip shape, serration level, slip angle, and shear slip distance were investigated. Cutting zone boundaries (tool-chip contact length, length of shear plane, and critical slip plane) and cutting zone area were obtained. The results showed that discontinuous, long-curling, and continuous chips were formed at low, medium, and high speeds, respectively. Serration level, shear slip distance, and slip angle rose with increasing cutting speed. The length of shear plane, tool-chip contact, and critical slip plane varied subtly with increased cutting speed, and rose noticeably with increased feed. Cutting zone area grew weakly with increased cutting speed, levelling off at high cutting speed; however, it rose noticeably with increased feed. This study furthers our understanding of the shear slip phenomenon and the mechanism of serrated chip formation.

A Quantum TITO Diversity Transmission Scheme for the Entangled-State Message Based on Quantum Teleportation

Jinjing Shi,Ronghua Shi,Danping Xu,Moon Ho Lee 대한전자공학회 2011 대한전자공학회 학술대회 Vol.2011 No.12

A quantum TITO (Two-Input-Two-Output) diversity transmission scheme for the entangled-state message is proposed by generalizing the wireless transmission technique to the quantum field. The TITO quantum teleportation can be implemented with Bell states in order to enhance the capacity and fidelity of the quantum channel, in which a quantum signal sequence with η entangled quantum states can be transmitted through the TITO quantum channel by applying the diversity technology. The fidelity analysis demonstrates that the quantum TITO teleportation can be performed with an expected fidelity.

Epigenetic inactivation of ACAT1 promotes epithelial-mesenchymal transition of clear cell renal cell carcinoma

Han Peipei,Wu Shu,Li Limei,Li Danping,Zhao Jun,Zhang Haishan,Wang Yifang,Zhong Xuemin,Zhang Zhe,Li Ping,Matskova Liudmila,Zhou Xiaoying 한국유전학회 2022 Genes & Genomics Vol.44 No.4

Background: Acetyl-CoA acyltransferase 1 (ACAT1) is a key enzyme catalyzing the production of mitochondrial ketone bodies. We have shown that ACAT1 is down-regulated in kidney renal clear cell carcinoma (KIRC) previously. Objective: To investigate the reasons for downregulation of ACAT1 in KIRC and explore the underlying mechanisms involved in metastatic inhibition regulated by ACAT1. Methods: The Gene Expression Omnibus (GEO) database was queried for meta-analysis of ACAT1 mRNA expression in KIRC. The UALCAN website was used to compare the methylation levels of the ACAT1 promoter region in KIRC and normal tissues. RT-qPCR was used to quantitate ACAT1 transcription levels. The GCBI and Tarbase V.8 databases were used to predict miRNAs that may target the mRNA of ACAT1. The correlation between mRNA expression of ACAT1, MMP7 (matrix metallopeptidase 7), CDH1 (E-cadherin), EpCAM (epithelial cell adhesion molecule), and VIM (vimentin) was analyzed. Extracellular MMP7 protein was quantitated using an ELISA assay. Results: The methylation level of the ACAT1 promoter region in KIRC was significantly higher than that in the normal kidney tissues. The ACAT1 mRNA expression in the KIRC cell lines was restored after treatment with 5-aza-dC (p < 0.05). MiR-21-5p is a conserved microRNA targeting ACAT1. It is expressed at a significantly higher level in KIRC than in normal tissues (p < 0.001). MiR-21-5p miRNA expression negatively correlates with ACAT1 mRNA expression. The expression of miR-21-5p is higher at the T3-T4 stages and in the histologic grades G3-G4. Patients with high miR-21-5p expression tended to have lower overall survival, suggesting that miR-21-5p could serve as a potentially valuable diagnostic biomarker for KIRC (AUC = 0.957; p < 0.001). A mimetic of miR-21-5p inhibited the expression of ACAT1 mRNA and protein. In addition, ACAT1 mRNA expression positively correlates with CDH1 and EpCAM but is negatively correlated with VIM. Overexpression of ACAT1 suppresses the secretion of MMP7 in KIRC cells. Conclusion: Expression of ACAT1 in KIRC is controlled at two levels, firstly by the hypermethylation of the ACAT1 promoter region and secondly by overexpression of miR-21-5p. Downregulation of ACAT1 expression correlates with epithelial-mesenchymal transition (EMT).

On the Feasibility of High Speed Railway mmWave Channels in Tunnel Scenario

Li, Guangkai,Ai, Bo,He, Danping,Zhong, Zhangdui,Hui, Bing,Kim, Junhyeong Hindawi Limited 2017 WIRELESS COMMUNICATIONS AND MOBILE COMPUTING Vol.2017 No.-

<P>Rail traffic is widely acknowledged as an efficient and green transportation pattern and its evolution attracts a lot of attention. However, the key point of the evolution is how to develop the railway services from traditional handling of the critical signaling applications only to high data rate applications, such as real-time videos for surveillance and entertainments. The promising method is trying to use millimeter wave which includes dozens of GHz bandwidths to bridge the high rate demand and frequency shortage. In this paper, the channel characteristics in an arched railway tunnel are investigated owing to their significance of designing reliable communication systems. Meantime, as millimeter wave suffers from higher propagation loss, directional antenna is widely accepted for designing the communication system. The specific changes that directional antenna brings to the radio channel are studied and compared to the performances of omnidirectional antenna. Note that the study is based on enhanced wide-band ray tracing tool where the electromagnetic and scattering parameters of the main materials of the tunnel are measured and fitted with predicting models.</P>

Fluidelastic instability of a tube array in two-phase cross-flow considering the effect of tube material

Huantong Liu,Jiang Lai,Lei Sun,Pengzhou Li,Lixia Gao,Danping Yu 한국원자력학회 2019 Nuclear Engineering and Technology Vol.51 No.8

Fluidelastic instability of a tube array is a key factor of the security of a nuclear power plant. An unsteady model of the fluidelastic instability of a tube array subjected to two-phase flow was developed to analyze the fluidelastic instability of tube bundles in two-phase flow. Based on this model, a computational program was written to calculate the eigenvalue and the critical velocity of the fluidelastic instability. The unsteady model and the program were verified by comparing with the experimental results reported previously. The influences of void fraction and the tube's material properties on the critical velocity were investigated. Numerical results showed that, with increasing the void fraction of the two-phase flow, the tube array becomes more stable. The results indicate that the critical velocities of the tube array made of stainless are much higher than those of the other two tube arrays within void fraction ranging from 20%to 80%.

Temperature dependent of thermal expansion and ferroelectric properties for BiAlO3-modified BaTiO3 lead-free ceramics

Shaoying Zheng,Longlong Fan,Erika Odendo,Laijun Liu,Danping Shi,Guizhong Li,Jun Chen,Liang Fang,Brahim Elouadi 한국물리학회 2014 Current Applied Physics Vol.14 No.1

Perovskite structure (1 x)BaTiO3exBiAlO3 (BTexBA, x ¼ 0.05, 0.08 and 0.1, corresponding to BTe5BA, BTe8BA and BTe10BA, respectively) ceramics were prepared by a solid state reaction route. Crystal structure of BTexBA ceramics was determined by using XRD. Dielectric properties were studied as a function of temperature at different frequencies, which indicated that the phase transition temperature (Tm) decreased with increasing x. With increasing temperature, thermal expansion dl/l increased while thermal expansion coefficient a had weak concentration dependence. The Burns temperature was much higher than the transition temperature Tm for the BTe5BA and BTe10BA ceramics. Polarization hysteresis loops (PeE), electrostrictive (SeE) and S versus P2 (SeP2) at different temperatures were displayed. Pmax slightly decreased due to thermally activated leakage current, meanwhile, Smax decreased at above Tm with the contribution of ferroelectric domain reorientation decreased. The electrostrictive coefficient Q value was clearly larger than that of lead-based electrostrictors at room temperature. Furthermore, it exhibited a slim loop with negligible hysteresis and a subtle linear feature at higher temperature.