T-START: Time, Status and Region Aware Taxi Mobility Model for Metropolis

( Haiquan Wang ),( Shuo Lei ),( Binglin Wu ),( Yilin Li ),( Bowen Du ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.7

The mobility model is one of the most important factors that impacts the evaluation of any transportation vehicular networking protocols via simulations. However, to obtain a realistic mobility model in the dynamic urban environment is a very challenging task. Several studies extract mobility models from large-scale real data sets (mostly taxi GPS data) in recent years, but they do not consider the statuses of taxi, which is an important factor affected taxi’s mobility. In this paper, we discover three simple observations related to the taxi statuses via mining of real taxi trajectories: (1) the behavior of taxi will be influenced by the statuses, (2) the macroscopic movement is related with different geographic features in corresponding status, and (3) the taxi load/drop events are varied with time period. Based on these three observations, a novel taxi mobility model (T-START) is proposed with respect to taxi statuses, geographic region and time period. The simulation results illustrate that proposed mobility model has a good approximation with reality in trajectory samples and distribution of nodes in four typical time periods.

An Interval Algebra-based Modeling and Routing Method in Bus Delay Tolerant Network

( Haiquan Wang ),( Weijian Ma ),( Hengkun Shi ),( Chunhe Xia ) 한국인터넷정보학회 2015 KSII Transactions on Internet and Information Syst Vol.9 No.4

In bus delay-tolerant networks, the route of bus is determinate but its arrival time is indeterminate. However, most conventional approaches predict future contact without considering its uncertainty, which makes a limitation on routing performance. A novel approach is proposed by employing interval algebra to characterize the contact`s uncertainty and time-varying nature. The contact is predicted by using the Bayesian estimation to achieve a better routing performance. Simulation results show that this approach achieves a good balance between delivery latency and delivery ratio.

Simulation Studies on the Hemodynamics of a Centrifugal Ventricular Assist pump

Haiquan Feng,Dong Wang,Kun Wang,Mingxin Zhu 한국유체기계학회 2019 International journal of fluid machinery and syste Vol.12 No.3

The present study was aimed to reveal the possible interactions between the left ventricular assist pump and the blood. The study presented in here adopted the computational fluid dynamics approach to analyze the effects of variations in blade height, rotation speed, and suspension height on the dynamic performance of the left ventricular assist pump. In addition, the 3D printing technology was tested as a reliable of manufacture of the assembly parts the left ventricular assist pump. The study was designed and conducted only after system debugging was accomplished. The computer-aided simulation results showed that the blade height, rotation speed and suspension height had varied functional on the dynamic performance of the device. Comparison of the influence degree of each factor to that of the blood indicated that rotation speed has the largest impact, followed by the blade height and finally the suspension height. At the same time, the experimental results proved that the design principle was rational and if prepared the left ventricular assist pump could operate successfully. The computer-aided simulation and experiment also reproduced the possible effects of the various factors on the blood and provided a theoretical reference for the design of the centrifugal ventricular assist pump.

Buckling of porosity-dependent bi-directional FG nanotube using numerical method

Wang, Haiquan,Zandi, Yousef,Gholizadeh, Morteza,Issakhov, Alibek Techno-Press 2021 Advances in nano research Vol.10 No.5

This article focused on studying the buckling behavior of two-dimensional functionally graded (2D-FG) nanosize tubes, including porosity based on first shear deformation and higher-order theory of tube. The nano-scale tube is simulated based on the nonlocal gradient strain theory, and the general equations and boundary conditions are derived using Hamilton's principle for the Zhang-Fu's tube model (as higher-order theory) and Timoshenko beam theory. Finally, the derived equations are solved using a numerical method for both simply-supported and clamped boundary conditions. The parametric study is performed to study the effects of different parameters such as axial and radial FG power indexes, porosity parameter, nonlocal gradient strain parameters on the buckling behavior of di-dimensional functionally graded porous tube.

Effect of Iliac Vein Stent with Crown on Flow Field of Bifurcation

WenYing,Haiquan Feng,Xiaoqiang Li,Xiaotian Wang,Ping Cao,Yonggang Wang 한국유체기계학회 2020 International journal of fluid machinery and syste Vol.13 No.2

Interference in blood flow at bifurcation after stent implantation is one of the important causes of thrombosis. Therefore, it is necessary to research the effects of stent structure and implantation position on hemodynamics. Computational fluid dynamics and experimental comparative research methods were used to analyze the influence of stent structure and position of stent on exit velocity, pressure difference between inlet and outlet, higher and lower wall shear stress areas and contralateral flow field. It is indicated in the research that the effect of iliac vein stent implantation on the flow velocity and pressure distribution at the outlet is not obvious, but stent implantation has an influence on the proportion of low wall shear stress and high wall shear stress area in the iliac vein. The low wall shear stress area is inversely proportional to the height of the stent. After stent is implanted, proportion of the high wall shear stress area will decrease, but the degree of decline is not obvious. As the height of stent is increased, the disturbing effect of stent on contralateral blood flow becomes more pronounced. In addition, it is confirmed by the experiments in vitro and in vivo that stent with crown would effectively reduce the interference to the contralateral flow field and the risk of thrombosis and restenosis. Finite element analysis provides effective theoretical support for studying the influence of iliac vein stent implantation on blood flow field.

Resource Allocation for D2D Communication in Cellular Networks Based on Stochastic Geometry and Graph-coloring Theory

( Fangmin Xu ),( Pengkai Zou ),( Haiquan Wang ),( Haiyan Cao ),( Xin Fang ),( Zhirui Hu ) 한국인터넷정보학회 2020 KSII Transactions on Internet and Information Syst Vol.14 No.12

In a device-to-device (D2D) underlaid cellular network, there exist two types of co-channel interference. One type is inter-layer interference caused by spectrum reuse between D2D transmitters and cellular users (CUEs). Another type is intra-layer interference caused by spectrum sharing among D2D pairs. To mitigate the inter-layer interference, we first derive the interference limited area (ILA) to protect the coverage probability of cellular users by modeling D2D users’ location as a Poisson point process, where a D2D transmitter is allowed to reuse the spectrum of the CUE only if the D2D transmitter is outside the ILA of the CUE. To coordinate the intra-layer interference, the spectrum sharing criterion of D2D pairs is derived based on the (signal-to-interference ratio) SIR requirement of D2D communication. Based on this criterion, D2D pairs are allowed to share the spectrum when one D2D pair is far from another sufficiently. Furthermore, to maximize the energy efficiency of the system, a resource allocation scheme is proposed according to weighted graph coloring theory and the proposed ILA restriction. Simulation results show that our proposed scheme provides significant performance gains over the conventional scheme and the random allocation scheme.

Simulation of the irradiation effect on hardness of Chinese HTGR A508-3 steels with CPFEM

Junfeng Nie,Pandong Lin,Yunpeng Liu,Haiquan Zhang,Xin Wang 한국원자력학회 2019 Nuclear Engineering and Technology Vol.51 No.8

Understanding the irradiation hardening effect of structural steels under various irradiation conditions plays an important role in developing advanced nuclear systems. Such being the case, a crystal plasticity model for body-centered cubic (BCC) crystal based on the density of dislocations and irradiation defects is summarized and numerically implemented in this paper. Based on this model, nano-indentation hardness of Chinese A508-3 steels with ion irradiation is calculated. Very good agreement is observed between simulation and experimental data of several different irradiation doses subjected to various operating temperatures, from which, it can be concluded that indentation hardness increases with increasing irradiation dose at both room temperature and high temperature. Consequently, the validity of this model has been proved properly, and furthermore, the model established in this paper could guide the study of irradiation hardening effect and temperature effect to some extent.

Correlation between in vitro fertilization and artificial insemination in Holstein bulls

Sun Wei,Li Yunxia,Su Jie,Bao Xiangnan,Ding Rui,Zhao Gaoping,Cao Guifang,Hu Shuxiang,Wang Jianguo,Sun Qingyuan,Yu Haiquan,Li Xihe 아세아·태평양축산학회 2021 Animal Bioscience Vol.34 No.12

Objective: Owing to the lack of a breeding index for efficient and quick fertility evaluations of Holstein bulls when using traditional or genome-wide detection methods, this study aimed to determine whether in vitro fertilization (IVF) could be used as an indicator of conception rate of artificial insemination (AI).Methods: Conventional and sexed frozen semen from nine bulls were used for IVF and AI.Results: The IVF and AI conception rates of each bull were confirmed to be positively correlated between the conventional frozen and sexed frozen semen. The correlation coefficient R values of nine bulls between IVF and AI methods were 0.73 and 0.97 for the conventional frozen and sexed frozen semen, respectively. The average conception rate of three bulls undergoing AI was 69.5% and 64.2%, 61.8% and 58.8%, and 48.2% and 46.2% in first-, second-, and third-born cows when conventional frozen and sexed frozen semen were used, respectively, which showed a positive correlation with the fertilization rate in the same parity. We propose an evaluation standard to assess the fertilization ability of bulls based on their IVF test results, which is categorized into three grades: grade one, normal fertility bull with an AI conception rate of 40%±5% and IVF rate of 45% to 60%; grade two, higher fertility bull with an AI conception rate of 50%±5% and IVF rate of 61% to 80%; and grade three, highest fertility bull with an AI conception rate of 60%±5% and IVF rate of >80%.Conclusion: These findings reveal that IVF results can be used as a breeding index for bulls to evaluate their AI conception ability, which may shorten the time required to select bulls for breeding. Objective: Owing to the lack of a breeding index for efficient and quick fertility evaluations of Holstein bulls when using traditional or genome-wide detection methods, this study aimed to determine whether in vitro fertilization (IVF) could be used as an indicator of conception rate of artificial insemination (AI). Methods: Conventional and sexed frozen semen from nine bulls were used for IVF and AI. Results: The IVF and AI conception rates of each bull were confirmed to be positively correlated between the conventional frozen and sexed frozen semen. The correlation coefficient R values of nine bulls between IVF and AI methods were 0.73 and 0.97 for the conventional frozen and sexed frozen semen, respectively. The average conception rate of three bulls undergoing AI was 69.5% and 64.2%, 61.8% and 58.8%, and 48.2% and 46.2% in first-, second-, and third-born cows when conventional frozen and sexed frozen semen were used, respectively, which showed a positive correlation with the fertilization rate in the same parity. We propose an evaluation standard to assess the fertilization ability of bulls based on their IVF test results, which is categorized into three grades: grade one, normal fertility bull with an AI conception rate of 40%±5% and IVF rate of 45% to 60%; grade two, higher fertility bull with an AI conception rate of 50%±5% and IVF rate of 61% to 80%; and grade three, highest fertility bull with an AI conception rate of 60%±5% and IVF rate of >80%. Conclusion: These findings reveal that IVF results can be used as a breeding index for bulls to evaluate their AI conception ability, which may shorten the time required to select bulls for breeding.