Nonlinear Wave and Currents Loads Analysis of Offshore Wind Turbines

Xiaobo Chen,Jing Li,Jianyun Chen 대한토목학회 2014 KSCE JOURNAL OF CIVIL ENGINEERING Vol.18 No.6

In recent years, the offshore wind energy has increased in popularity due to the demand for renewable energy. Being built in a verydynamic environment, the nonlinear wave and current loads on offshore wind turbines are required to be investigated for design. Thewave and current kinematics were calculated by the model that the wave propagates on a linear shear current which was developedby Dalrymple based on the stream function wave theory. The wave and current loads were calculated based on the Morison equation. For the engineering application purpose, some problems such that the wave and current kinematics models, the wave and currentcombination schemes in statistics, and the free surface’s influences on wave and current loads were discussed. At the end, thenonlinear results were compared with linear results to verify the calculation correctness.

Urban Flood Resilience Assessment Based on VIKOR-GRA: A Case Study in Chongqing, China

Xiaobo Chen,Zupei Guo,Hengyu Zhou,Xikun Qian,Xuesheng Zhang 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.9

Flooding has been considered as one of the major challenges of urban hazards resilience assessment. Improving urban flood risk resilience has become a critical issue for city management. However, urban flood assessment models on the resilience perspective are rare. Meanwhile, in the perspective of resilience, the existing studies using the TOPSIS (Technique for Order Preference by Similarity to an Ideal Solution) assessment method for disaster assessment lack consideration of evaluation scenarios located in the midpoint of positive and negative ideal solutions. To address these issues, this study establishes an urban flood disaster resilience assessment model, selects indicators according to the TOSE (Technical, Organizational, Social and Economic) framework, ranks cities through the VIKOR-GRA (VlseKriterijumska Optimizacija I Kompromisno Resenje, Grey Relational Analysis) method, and proposes measures to improve urban disaster resilience through the resilience assessment. Chongqing is taken as an example in this study to verify the feasibility and effectiveness of the proposed model, and practical management opinions are presented to improve flood resilience in these cities. Through the analysis of actual cases, it can be seen that the model has good applicability and can better reflect the actual situation. The knowledge of flood resilience assessment methods is of particular value to policy makers, researchers and industry professionals in assessing potential risks and recognizing the importance of flood prevention mechanisms.

PARALLEL PARKING PATH PLANNING BASED ON IMPROVED ARCTANGENT FUNCTION OPTIMIZATION

Qiping Chen,Lu Gan,Bo Chen,Qin Liu,Xiaobo Zhang 한국자동차공학회 2023 International journal of automotive technology Vol.24 No.1

Aiming at the problems of small parking space and poor parking effect for existing parallel parking, this paper proposes a parallel parking path planning based on improved arctangent function optimization. Firstly, the vehicle parking kinematics model is established, and the vehicle parameters are determined according to the three classical models. Secondly, the parking space model is established, and the most reasonable parking space parameters are selected according to the minimum parking space. Then, aiming at the problems of abrupt curvature of the designed arc-line-arc initial path, unsmooth path, large yaw angle at the end and large parking space, an improved arctangent function model is proposed, the parking constraints are established, the absolute value of vehicle yaw angle is taken as the objective function, and the parameters are optimized by genetic algorithm. Finally, it is verified by simulation experiments. The results show that the method can achieve smoother path, smaller parking space and more ideal parking posture, meet the requirements of stability, safety and comfort in the process of parallel parking, and improve the ability of parallel parking. Therefore, this method can provide a theoretical reference for path planning in automatic parking technology.

Microsatellite primers in red bayberry, <i>Myrica rubra</i> (Myricaceae)

Xie, Xiaobo,Qiu, Yingying,Ke, Liping,Zheng, Xiliang,Wu, Guanting,Chen, Jinqing,Qi, Xingjiang,Ahn, Sangnag Wiley (John WileySons) 2011 American journal of botany Vol.98 No.4

<P>Microsatellite markers were developed in Myrica rubra to investigate potential hybridization events within or between M. rubra and its closely related species.</P>

Tunable Low Phase-noise Microwave Generation Utilizing an Optoelectronic Oscillator and a Fiber Bragg Grating

Zhuansun, Xiaobo,Chen, Yiwang,Zhang, Pin,Yin, Qin,Ni, Jiazheng,Dong, Xiaohua Optical Society of Korea 2018 Current Optics and Photonics Vol.2 No.1

A tunable low-phase-noise microwave generation structure that utilizes an optoelectronic oscillator (OEO) and a fiber Bragg grating (FBG) is proposed and experimentally demonstrated in this article. This structure has no particular requirement for the band width of the laser, and its tunability is realized through adjusting the central frequency of the tunable FBG. A detailed theoretical analysis is established and confirmed via an experiment. A high-purity microwave signal with a frequency tunable from 6 to 12 GHz is generated. The single-sideband phase noise of the generated signal at 10.2 GHz is -117.2 dBc/Hz, at a frequency offset of 10 kHz.

Test-Retest Reliability of “High-Order” Functional Connectivity in Young Healthy Adults

Zhang, Han,Chen, Xiaobo,Zhang, Yu,Shen, Dinggang Frontiers Media S.A. 2017 Frontiers in neuroscience Vol.11 No.-

<P>Functional connectivity (FC) has become a leading method for resting-state functional magnetic resonance imaging (rs-fMRI) analysis. However, the majority of the previous studies utilized pairwise, temporal synchronization-based FC. Recently, high-order FC (HOFC) methods were proposed with the idea of computing “correlation of correlations” to capture high-level, more complex associations among the brain regions. There are two types of HOFC. The first type is <I>topographical profile similarity-based HOFC</I> (<I>t</I>HOFC) and its variant, <I>associated HOFC</I> (<I>a</I>HOFC), for capturing different levels of HOFC. Instead of measuring the similarity of the original rs-fMRI signals with the traditional FC (low-order FC, or LOFC), tHOFC measures the similarity of LOFC profiles (i.e., a set of LOFC values between a region and all other regions) between each pair of brain regions. The second type is <I>dynamics-based HOFC</I> (<I>d</I>HOFC) which defines the quadruple relationship among every four brain regions by first calculating two pairwise dynamic LOFC “time series” and then measuring their temporal synchronization (i.e., temporal correlation of the LOFC fluctuations, not the BOLD fluctuations). Applications have shown the superiority of HOFC in both disease biomarker detection and individualized diagnosis than LOFC. However, no study has been carried out for the assessment of test-retest reliability of different HOFC metrics. In this paper, we systematically evaluate the reliability of the two types of HOFC methods using test-retest rs-fMRI data from 25 (12 females, age 24.48 ± 2.55 years) young healthy adults with seven repeated scans (with interval = 3–8 days). We found that all HOFC metrics have satisfactory reliability, specifically (1) fair-to-good for tHOFC and aHOFC, and (2) fair-to-moderate for dHOFC with relatively strong connectivity strength. We further give an in-depth analysis of the biological meanings of each HOFC metric and highlight their differences compared to the LOFC from the aspects of cross-level information exchanges, within-/between-network connectivity, and modulatory connectivity. In addition, how the dynamic analysis parameter (i.e., sliding window length) affects dHOFC reliability is also investigated. Our study reveals unique functional associations characterized by the HOFC metrics. Guidance and recommendations for future applications and clinical research using HOFC are provided. This study has made a further step toward unveiling more complex human brain connectome.</P>

An Active Construction Dynamic Schedule Management Model: Using the Fuzzy Earned Value Management and BP Neural Network

Fangfang Yu,Xiaobo Chen,Clark A. Cory,Zhixuan Yang,Yingwen Hu 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.7

Project schedule management is an important aspect of project management. Earned value management (EVM) and its extension methods are widely adopted in project schedule management in various previous studies, however, most of these studies adopted schedule performance indicators based on definiteness condition and historical data, which ignored the impact of uncertainty and dynamics. So the decision risk in schedule management has been increased dramatically. Therefore, this paper proposed an active construction dynamic schedule management model based on fuzzy earned value management (F-EVM) and BP neural network (BP-NN). Firstly, the fuzzy theory was introduced into EVM to evaluate the schedule performance when the project finish schedule cannot be deterministic expression. Then, the main resource planning was functioned as input variables to predict the schedule in advance through BP-NN. Finally, the future action plans was adjusted based on the results to achieve active control of the project schedule. The case results indicated that the introduction of F-EVM effectively reduced influence of subjective estimation on uncertainty in the data measurement process. And the proposed dynamic schedule management model gave a 32.06% better mean absolute percentage error (MAPE) than the existing methods for estimated project duration. Hence, the proposed model provided a more accurate estimation of the project duration and considered the uncertainty and dynamics of the construction project, thereby achieving more effective management of project schedule.

Gypenoside XVII protects against myocardial ischemia and reperfusion injury by inhibiting ER stress – induced mitochondrial injury

Yingli Yu,MinWang,Rongchang Chen,Xiao Sun,Guibo Sun,Xiaobo Sun 고려인삼학회 2021 Journal of Ginseng Research Vol.45 No.6

Background: Effective strategies are dramatically needed to prevent and improve the recovery frommyocardialischemia and reperfusion (I/R) injury. Direct interactions between the mitochondria and endoplasmic reticulum(ER) during heart diseases have been recently investigated. This study was designed to explore the cardioprotectiveeffects of gypenoside XVII (GP-17) against I/R injury. The roles of ER stress, mitochondrial injury,and their crosstalk within I/R injury and in GP-17einduced cardioprotection are also explored. Methods: Cardiac contractility function was recorded in Langendorff-perfused rat hearts. The effects ofGP-17 on mitochondrial function including mitochondrial permeability transition pore opening, reactiveoxygen species production, and respiratory function were determined using fluorescence detection kitson mitochondria isolated from the rat hearts. H9c2 cardiomyocytes were used to explore the effects ofGP-17 on hypoxia/reoxygenation. Results: We found that GP-17 inhibits myocardial apoptosis, reduces cardiac dysfunction, and improvescontractile recovery in rat hearts. Our results also demonstrate that apoptosis induced by I/R is predominantlymediated by ER stress and associated with mitochondrial injury. Moreover, the cardioprotectiveeffects of GP-17 are controlled by the PI3K/AKT and P38 signaling pathways. Conclusion: GP-17 inhibits I/R-induced mitochondrial injury by delaying the onset of ER stress throughthe PI3K/AKT and P38 signaling pathways.

Learning-based structurally-guided construction of resting-state functional correlation tensors

Zhang, Lichi,Zhang, Han,Chen, Xiaobo,Wang, Qian,Yap, Pew-Thian,Shen, Dinggang Elsevier 2017 Magnetic resonance imaging Vol.43 No.-

<P><B>Abstract</B></P> <P>Functional magnetic resonance imaging (fMRI) measures changes in blood-oxygenation-level-dependent (BOLD) signals to detect brain activities. It has been recently reported that the spatial correlation patterns of resting-state BOLD signals in the white matter (WM) also give WM information often measured by diffusion tensor imaging (DTI). These correlation patterns can be captured using functional correlation tensor (FCT), which is analogous to the diffusion tensor (DT) obtained from DTI. In this paper, we propose a noise-robust FCT method aiming at further improving its quality, and making it eligible for further neuroscience study. The novel FCT estimation method consists of three major steps: <I>First</I>, we estimate the initial FCT using a patch-based approach for BOLD signal correlation to improve the noise robustness. <I>Second</I>, by utilizing the relationship between functional and diffusion data, we employ a regression forest model to learn the mapping between the initial FCTs and the corresponding DTs using the <I>training data</I>. The learned forest can then be applied to predict the DTI-like tensors given the initial FCTs from the testing fMRI data. <I>Third</I>, we re-estimate the enhanced FCT by utilizing the DTI-like tensors as a feedback guidance to further improve FCT computation. We have demonstrated the utility of our enhanced FCTs in Alzheimer's disease (AD) diagnosis by identifying mild cognitive impairment (MCI) patients from normal subjects.</P>

iGreenhouse : A Case Study for Connecting Physical Devices into Mobile Social Networks

Jiajin Zhang,Lichang Chen,Xiaobo Cai,Quan Gao 보안공학연구지원센터 2015 International Journal of Smart Home Vol.9 No.6

Social networks have become extremely popular in recent years. A new requirement of connecting physical devices into social networks is emerging gradually. In this paper, we propose a case study to explore the effectiveness of connecting devices into mobile social networks for status monitoring and controlling. In our work, we developed iGreenhouse, a greenhouse can post its environment information automatically to the most popular mobile social networks Wechat in China, and Wechat users are able to remotely control the devices in the greenhouse easily. Experiment results show that our proposed approach is feasible, cost-effective and flexible. Therefore our solution can provide an alternative ubiquitous platform for monitoring and controlling of connected devices.