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123 results on '"Ji, Yuqi"'

1. Navigate Biopsy with Ultrasound under Augmented Reality Device: Towards Higher System Performance

Author

Li, Haowei, Yan, Wenqing, Zhao, Jiasheng, Ji, Yuqi, Qian, Long, Ding, Hui, Zhao, Zhe, and Wang, Guangzhi

Subjects
Computer Science - Human-Computer Interaction, Computer Science - Computer Vision and Pattern Recognition
Abstract

Purpose: Biopsies play a crucial role in determining the classification and staging of tumors. Ultrasound is frequently used in this procedure to provide real-time anatomical information. Using augmented reality (AR), surgeons can visualize ultrasound data and spatial navigation information seamlessly integrated with real tissues. This innovation facilitates faster and more precise biopsy operations. Methods: We developed an AR biopsy navigation system with low display latency and high accuracy. Ultrasound data is initially read by an image capture card and streamed to Unity via net communication. In Unity, navigation information is rendered and transmitted to the HoloLens 2 device using holographic remoting. Retro-reflective tool tracking is implemented on the HoloLens 2, enabling simultaneous tracking of the ultrasound probe and biopsy needle. Distinct navigation information is provided during in-plane and out-of-plane punctuation. To evaluate the effectiveness of our system, we conducted a study involving ten participants, for puncture accuracy and biopsy time, comparing to traditional methods. Results: Our proposed framework enables ultrasound visualization in AR with only $16.22\pm11.45ms$ additional latency. Navigation accuracy reached $1.23\pm 0.68mm$ in the image plane and $0.95\pm 0.70mm$ outside the image plane. Remarkably, the utilization of our system led to $98\%$ and $95\%$ success rate in out-of-plane and in-plane biopsy. Conclusion: To sum up, this paper introduces an AR-based ultrasound biopsy navigation system characterized by high navigation accuracy and minimal latency. The system provides distinct visualization contents during in-plane and out-of-plane operations according to their different characteristics. Use case study in this paper proved that our system can help young surgeons perform biopsy faster and more accurately.

Published
2024

2. A VR Environment for Cervical Tumor Segmentation Through Three-Dimensional Spatial Interaction

Author

Zhang, Nan, Huang, Tianqi, Liu, Jiayuan, Ji, Yuqi, Ma, Longfei, Zhang, Xinran, Liao, Hongen, Magjarević, Ratko, Series Editor, Ładyżyński, Piotr, Associate Editor, Ibrahim, Fatimah, Associate Editor, Lackovic, Igor, Associate Editor, Rock, Emilio Sacristan, Associate Editor, Wang, Guangzhi, editor, Yao, Dezhong, editor, Gu, Zhongze, editor, Peng, Yi, editor, Tong, Shanbao, editor, and Liu, Chengyu, editor

Published
2024
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5. Ethylene-regulated asymmetric growth of the petal base promotes flower opening in rose (Rosa hybrida)

Author

Cheng, Chenxia, Yu, Qin, Wang, Yaru, Wang, Hong, Dong, Yuhan, Ji, Yuqi, Zhou, Xiaofeng, Li, Yonghong, Jiang, Cai-Zhong, Gan, Su-Sheng, Zhao, Liangjun, Fei, Zhangjun, Gao, Junping, and Ma, Nan

Subjects
Plant Biology, Biological Sciences, Cyclopropanes, Ethylenes, Flowers, Gene Expression Regulation, Plant, Gene Silencing, Plant Cells, Plant Growth Regulators, Plant Proteins, Plants, Genetically Modified, Rosa, Biochemistry and Cell Biology, Genetics, Plant Biology & Botany, Plant biology
Abstract

Flowers are the core reproductive structures and key distinguishing features of angiosperms. Flower opening to expose stamens and gynoecia is important in cases where pollinators much be attracted to promote cross-pollination, which can enhance reproductive success and species preservation. The floral opening process is accompanied by the coordinated movement of various floral organs, particularly petals. However, the mechanisms underlying petal movement and flower opening are not well understood. Here, we integrated anatomical, physiological, and molecular approaches to determine the petal movement regulatory network using rose (Rosa hybrida) as a model. We found that PETAL MOVEMENT-RELATED PROTEIN1 (RhPMP1), a homeodomain transcription factor (TF) gene, is a direct target of ETHYLENE INSENSITIVE3, a TF that functions downstream of ethylene signaling. RhPMP1 expression was upregulated by ethylene and specifically activated endoreduplication of parenchyma cells on the adaxial side of the petal (ADSP) base by inducing the expression of RhAPC3b, a gene encoding the core subunit of the Anaphase-Promoting Complex. Cell expansion of the parenchyma on the ADSP base was subsequently enhanced, thus resulting in asymmetric growth of the petal base, leading to the typical epinastic movement of petals and flower opening. These findings provide insights into the pathway regulating petal movement and associated flower-opening mechanisms.?.

Published
2021

7. Formation Control Strategy of Multiple Mobile Robots Cooperative Operation Based on Backstepping Method

Author

LIU Yuming, ZHAO Yong, DONG Zhengjian, WANG Ping, JI Yuqi

Subjects
formation control, backstepping method, movement state, state estimation, Engineering (General). Civil engineering (General), TA1-2040, Chemical engineering, TP155-156, Naval architecture. Shipbuilding. Marine engineering, VM1-989
Abstract

A multi-shift tooling coordinated operation control strategy based on the backstepping method is investigated, a desired motion state planning scheme based on the improved artificial potential field method and the pure trajectory tracking method is proposed, and the actual situation is determined according to the adaptive Monte Carlo positioning method. For the estimated value of the motion state, a queue controller in combination the anti-stepping method and the virtual pilot following method is designed. A simulation model based on the robot operation system (ROS) environment is constructed, and the simulation is verified. The results show that the proposed formation error calculation method can improve the accuracy of error estimation. The formation control strategy can make the formation error converge within 6.2 s, and the designed formation controller can meet the operation requirements of multi-shift tooling.

Published
2023
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14. Efficient Defense Against Adversarial Attacks and Security Evaluation of Deep Learning System

Author

Pang, Na, Hong, Sheng, Pan, Yang, Ji, Yuqi, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Woeginger, Gerhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Chen, Xiaofeng, editor, Yan, Hongyang, editor, Yan, Qiben, editor, and Zhang, Xiangliang, editor

Published
2020
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33. A Novel Fault-location Method for HVDC Transmission Lines Based on Concentric Relaxation Principle and Wavelet Packet

Author

Feng Wang, Ji Yuqi, Tao Yukun, Ping He, Congshan Li, and Cunxiang Yang

Subjects
Computer science, Network packet, 020209 energy, 020208 electrical & electronic engineering, 02 engineering and technology, Concentric, Fault (power engineering), Topology, Electronic, Optical and Magnetic Materials, Electric power transmission, Wavelet, 0202 electrical engineering, electronic engineering, information engineering, Relaxation (approximation), Electrical and Electronic Engineering
Abstract

Background: A novel fault location method of HVDC transmission line based on a concentric relaxation principle is proposed in this paper. Methods: Due to the different position of fault, the instantaneous energy measured from rectifier and inverter are different, and the ratio k between them is the relationship to the fault location d. Through the analysis of amplitude-frequency characteristics, we found that the wave attenuation characteristic of low frequency in the traveling wave is stable, and the amplitude of energy is larger, so we get the instantaneous energy ratio by using the low-frequency data. By using the method of wavelet packet decomposition, the voltage traveling wave signal was decomposed. Results: Finally, calculate the value k. By using the data fitting, the relative function of k and d can be got, that is the fault location function. Conclusion: After an exhaustive evaluation process considering different fault locations, fault resistances, and noise on the unipolar DC transmission system, four-machine two-area AC/DC parallel system, and an actual complex grid, the method presented here showed a very accurate and robust behavior.

Published
2020

37. Distributed Adaptive Neural Consensus Control for Stochastic Nonlinear Multiagent Systems with Whole State Delays and Multiple Constraints

Author

Ji Yuqi, Tao Yukun, Ping He, Feifei Yang, and Congshan Li

Subjects
Lyapunov function, Lyapunov stability, 0209 industrial biotechnology, Artificial neural network, Computer science, Multi-agent system, 02 engineering and technology, Computer Science Applications, Nonlinear system, symbols.namesake, Error function, 020901 industrial engineering & automation, Control and Systems Engineering, Control theory, Backstepping, symbols
Abstract

This paper presents a distributed adaptive neural tracking consensus control strategy for a class of stochastic nonlinear multiagent systems with whole state time delays, input and output constrains. The considered systems are involved in the existence of whole state delays and stochastic disturbances, which makes the controller design more difficult and complex. Firstly, time delays are related to unknown dynamic interactions with the whole states of the agent systems, and novel Lyapunov-Krasovskii functionals are constructed. Secondly, the smooth asymmetric saturation nonlinearity is given based on Gaussian error function, output constraints are achieved via barrier Lyapunov functions, and neural networks are utilized to deal with the completely unknown nonlinearities and stochastic disturbances. Then, based on Lyapunov stability theory, a delay-independent adaptive controller is developed via Lyapunov-Krasovskii functionals and backstepping technique, and it reduces the complexity of learning parameters. It is proved that the proposed approximation-based controller can guarantee that all closed-loop signals are cooperatively semi-globally uniformly ultimately bounded (CSGUUB), and the tracking errors between the followers and the leaders eventually converge to a small neighbourhood around the origin. Finally, simulation studies are carried out, and the simulation results verify the correctness and effectiveness of the proposed strategy.

Published
2020

40. Analysis of the Influence of 'Source-load' Time Series Changes on Voltage and Reactive Power Partitioning in Distribution Network

Author

Huili Wang, Chen Xuehan, Ji Yuqi, Ping He, Songlin Yang, and Xue Yuan

Subjects
Wind power, Control theory, Computer science, business.industry, Photovoltaic system, Sensitivity (control systems), Time series, AC power, business, Partition (database), Power (physics), Voltage
Abstract

With large scale of distributed generations(DGs) access to the distribution network, the complexity of system optimization and control increases considering the random output of DGs and load fluctuation. In this paper, the influence of DGs connected to the distribution network on voltage and reactive power partitioning is analyzed based on the time series variation characteristics of power source and power load. Firstly, based on the principle of voltage and reactive power partitioning, four indexes containing inter-region coupling degree, intra-region coupling degree, regional reactive power balance degree and regional reactive power reserve are selected as the partitioning evaluation indicators. Secondly, typical scenarios of the "source-load" time series are divided with the comprehensively analysis of the time series characteristics of wind power and photovoltaic output and the typical daily load curve. Then, the influence of the four partition evaluation indicators in multiple "source-load" scenarios is analyzed. Finally, case studies based on modified IEEE33 test system are performed, and the result verifies the influence of the variation of "source-load" time series output on voltage reactive power partitioning.

Published
2021

41. A Novel Voltage/var Sensitivity Calculation Method to Partition the Distribution Network Containing Renewable Energy

Author

Ji, Yuqi, Chen, Xuehan, He, Ping, Liu, Xiaomei, Wu, Xiaopeng, and Zhao, Chen

Abstract

As the current calculation method of voltage/var sensitivity (VVS) could not reflect the temporal variations of power sources and load, the paper proposes a novel VVS calculation method to partition the distribution network containing renewable energy. Firstly, the defects of the existing VVS calculation methods are analyzed, and a novel VVS calculation method is proposed by adding reactive power output perturbation to the reactive power source. Secondly, the VVS matrix is fuzzified to obtain the membership matrix between each node. Based on the membership relationship between the reactive power source nodes, the nodes with a strong coupling relationship are merged to determine the initial number of partitioning. Then, the final partitioning result is determined according to the affiliation between each load node and each reactive power source. Finally, the partitioning result is evaluated based on the partitioning membership indexes. The proposed approach is tested on the IEEE 33-node distribution test system, and numerical simulations verify the high efficiency of partitioning. The simulation results show that the proposed method can reflect the temporal variations of power sources and load, and ensure the reasonable distribution of voltage and reactive power in each zone. Background: The voltage/var control of the power system is an important means to ensure the safe, economic and stable operation of the system. Objective: The paper proposes a novel VVS calculation method to partition the distribution network containing renewable energy. Methods: Firstly, the existing problems of electrical distance index are analyzed. A novel VVS matrix calculation method is proposed, which calculates the VVS of each reactive power source to the remaining nodes by adding voltage/var output perturbation to the reactive power source. Secondly, the VVS matrix is fuzzified to obtain the membership matrix between each node. Based on the membership relationship between the reactive power source nodes, the power supply nodes with strong coupling relationship are merged to determine the initial number of the partitioning. Then, the final partitioning result is determined according to the affiliation between each load node and each reactive power source. Finally, the partitioning result is evaluated based on the sensitivity index of membership degree. Results: The proposed approach is tested on the IEEE 33-node distribution test system and numerical simulations verify high efficiency of the partitioning. The simulation results show that the proposed method can reflect the temporal variations of power sources and load, and ensure the reasonable distribution of voltage and reactive power in each zone. Conclusion: The proposed method can reflect the temporal variations of power sources and load, and ensure the reasonable distribution of voltage and reactive power in each zone. This paper proposed a fuzzy clustering partitioning based on a novel calculation method of VVS, which is suitable for the problem of variable voltage /var running state of the system under high-proportion DG access.

Published
2023
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43. Dynamic reactive power optimization of distribution network with distributed generation based on fuzzy time clustering.

Author

Ji, Yuqi, Chen, Xuehan, Wang, Tao, He, Ping, Jin, Nan, Li, Congshan, and Tao, Yukun

Subjects
*DISTRIBUTED power generation, *ON-load tap changers, *ELECTRICAL conductivity transitions, *ELECTRIC power distribution grids, *CAPACITOR banks
Abstract

In order to solve the coordinated optimization problem of distributed generation (DG), on‐load tap changer (OLTC) and capacitor banks, a dynamic reactive power optimization (DRPO) method based on fuzzy time clustering is proposed. In the method, fuzzy time clustering algorithm is used to cluster the static optimal switching sequence of OLTC and capacitor banks. The time decoupling of control variables is realized and it meets the constraints of the maximum switching times. Next, the influencing factors of DG reactive power limit are analysed. Considering the control ability of OLTC, capacitor banks and DG in voltage and reactive power optimization, a coordinated optimization method is proposed. Since the adjustment of OLTC tap position directly affects the voltage and reactive power distribution of the whole line, the switching time and tap position of OLTC are determined based on the static optimization results of each time and fuzzy time clustering algorithm. Then, the switching time of capacitor banks is determined by fuzzy time clustering algorithm. At last, the switching capacity of capacitor banks and DG reactive power are jointly optimized to get the final control scheme. The proposed method demonstrated good performance in the modified IEEE33 node system and two actual power grid examples. [ABSTRACT FROM AUTHOR]

Published
2022
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48. Enhancing Oscillation Damping in an Interconnected Power System with Integrated Wind Farms Using Unified Power Flow Controller

Author

Fushuan Wen, Ji Yuqi, Seyed Ali Arefifar, Tao Yukun, Ping He, and Congshan Li

Subjects
unified power flow controller (UPFC), Control and Optimization, Wind power, Renewable Energy, Sustainability and the Environment, business.industry, Computer science, Oscillation, eigenvalue analysis, lcsh:T, wind farm integration, Energy Engineering and Power Technology, power oscillation damping controller (PODC), Stability (probability), lcsh:Technology, Power (physics), Electric power system, power system, Control theory, Unified power flow controller, Electrical and Electronic Engineering, business, Engineering (miscellaneous), Energy (miscellaneous), Voltage
Abstract

The well-developed unified power flow controller (UPFC) has demonstrated its capability in providing voltage support and improving power system stability. The objective of this paper is to demonstrate the capability of the UPFC in mitigating oscillations in a wind farm integrated power system by employing eigenvalue analysis and dynamic time-domain simulation approaches. For this purpose, a power oscillation damping controller (PODC) of the UPFC is designed for damping oscillations caused by disturbances in a given interconnected power system, including the change in tie-line power, the changes of wind power outputs, and others. Simulations are carried out for two sample power systems, i.e., a four-machine system and an eight-machine system, for demonstration. Numerous eigenvalue analysis and dynamic time-domain simulation results confirm that the UPFC equipped with the designed PODC can effectively suppress oscillations of power systems under various disturbance scenarios.

Published
2019

49. Co‐Catalyzed Dehydrogenation Claisen Condensation of Secondary Alcohols with Esters†.

Author

Gao, Shuo, Hao, Wentao, Ji, Yuqi, Li, Xiulin, Zhang, Chunyan, and Zhang, Guoying

Subjects
*CLAISEN condensation, *DEHYDROGENATION, *CATALYTIC dehydrogenation, *KETONES, *CHEMOSELECTIVITY
Abstract

Comprehensive Summary Catalytic dehydrogenation, with its exceptional atom economy and chemoselectivity, offers a highly desirable yet challenging approach for converting multiple environmentally friendly alcohols into crucial molecules. Furthermore, the utilization of catalysts based on abundant elements found on Earth for alcohol dehydrogenation to produce acryl ketone holds significant promise as a versatile strategy in synthesizing key building blocks for numerous pharmaceutical applications. The present study describes a practical Co‐catalyzed cascade dehydrogenative Claisen condensation of secondary alcohols with esters, facilitating the synthesis of a wide range of 3‐hydroxy‐prop‐2‐en‐1‐ones. We introduce a catalytic system based on novel and scalable indazole NNP‐ligands coordinated to cobalt for efficient dehydrogenations of secondary alcohols, and propose a plausible reaction mechanism supported by control experiments and labeling studies. Notably, it allows for the streamlined synthesis of multiple pharmaceuticals in one‐pot. [ABSTRACT FROM AUTHOR]

Published
2024
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