UAVs Cooperative Attack Based on Archimedes Spiral

Zhenming LI,Chaoyong Li,Shuo Zhuo,Sai Chen 제어로봇시스템학회 2017 제어로봇시스템학회 국제학술대회 논문집 Vol.2017 No.10

This paper investigates a control of track based on Archimedes spiral. The objective is to control UAVs (Unmanned Aerial Vehicle) circled to the target under the preset track and in a certain time interval. For the circumstance of the known location of start point and target point of UAV, we put forward a control method of angular velocity, with fixed velocity and trajectory of UAV. And in this control method, based on the nature of the Archimedes spiral, the time of UAV from the start point to the target point can be accurately calculated.

Sealing design optimization of nuclear pressure relief valves based on the polynomial chaos expansion surrogate model

Zong Chaoyong,Shi Maolin,Li Qingye,Xue Tianhang,Song Xueguan,Li Xiaofeng,Chen Dianjing 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.4

Pressure relief valve (PRV) is one of the important control valves used in nuclear power plants, and its sealing performance is crucial to ensure the safety and function of the entire pressure system. For the sealing performance improving purpose, an explicit function that accounts for all design parameters and can accurately describe the relationship between the multi-design parameters and the seal performance is essential, which is also the challenge of the valve seal design and/or optimization work. On this basis, a surrogate model-based design optimization is carried out in this paper. To obtain the basic data required by the surrogate model, both the Finite Element Model (FEM) and the Computational Fluid Dynamics (CFD) based numerical models were successively established, and thereby both the contact stresses of valve static sealing and dynamic impact (between valve disk and nozzle) could be predicted. With these basic data, the polynomial chaos expansion (PCE) surrogate model which can not only be used for inputs-outputs relationship construction, but also produce the sensitivity of different design parameters were developed. Based on the PCE surrogate model, a new design scheme was obtained after optimization, in which the valve sealing stress is increased by 24.42% while keeping the maximum impact stress lower than 90% of the material allowable stress. The result confirms the ability and feasibility of the method proposed in this paper, and should also be suitable for performance design optimizations of control valves with similar structures.

The long non-coding RNA UPAT promotes gastric cancer cell progression via UHRF1

Liu Chaoyong,Hao De,Ai Minghua,Zhang Yan,Li Jie,Xu Chao 한국유전학회 2022 Genes & Genomics Vol.44 No.10

Background: LncRNA ubiquitin-like with PHD and RING finger domains 1 (UHRF1) protein associated transcript (UPAT) regulates the progression of many cancers. However, its role in gastric cancer (GC) is less frequently reported. Objective: In the context of the promoting effect of lncRNA on modulating GC progression, detailed insights into the role and underlying mechanism of UPAT in GC are the foothold in this study. Methods: Overall survival was calculated. The mRNA expressions of UPAT and UHRF1 were measured by qRT-PCR, and the protein expressions of UHRF1, Cyclin D1 and cleaved caspase-3 were determined by western blot. Cell viability, growth, migration and invasion were assessed by CCK-8, colony formation, wound healing and Transwell assays, respectively. Apoptosis rate and cell cycle were assayed by flow cytometry. Results: UPAT was overexpressed in GC tissue and cell lines. Decreased UPAT level was associated with higher overall survival. Down-regulation of UPAT diminished cell proliferation, Cyclin D1 expression, and migration and invasion rates, increased apoptosis rate and cleaved caspase-3 expression, and blocked cell cycle in AGS and NCI-N87 cells. UPAT expression in GC was positively correlated with UHRF1 expression. UHRF1 overexpression offset the inhibitory effects of UPAT down-regulation on cell proliferation, migration, invasion and cell cycle, and partially reversed the positive effect of UPAT down-regulation on apoptosis. Conclusion: UPAT might positively regulate the progression of GC via interacting with UHRF1. The UHRF1/UPAT axis revealed in the present study may provide a promising approach to intervene in the progression of GC.

Design optimization of a nuclear main steam safety valve based on an E-AHF ensemble surrogate model

Zong Chaoyong,Shi Maolin,Li Qingye,Liu Fuwen,Zhou Weihao,Song Xueguan 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.11

Main steam safety valves are commonly used in nuclear power plants to provide final protections from overpressure events. Blowdown and dynamic stability are two critical characteristics of safety valves. However, due to the parameter sensitivity and multi-parameter features of safety valves, using traditional method to design and/or optimize them is generally difficult and/or inefficient. To overcome these problems, a surrogate model-based valve design optimization is carried out in this study, of particular interest are methods of valve surrogate modeling, valve parameters global sensitivity analysis and valve performance optimization. To construct the surrogate model, Design of Experiments (DoE) and Computational Fluid Dynamics (CFD) simulations of the safety valve were performed successively, thereby an ensemble surrogate model (E-AHF) was built for valve blowdown and stability predictions. With the developed E-AHF model, global sensitivity analysis (GSA) on the valve parameters was performed, thereby five primary parameters that affect valve performance were identified. Finally, the ksigma method is used to conduct the robust optimization on the valve. After optimization, the valve remains stable, the minimum blowdown of the safety valve is reduced greatly from 13.30% to 2.70%, and the corresponding variance is reduced from 1.04 to 0.65 as well, confirming the feasibility and effectiveness of the optimization method proposed in this paper

A Distributed Coverage Algorithm for Multi-UAV with Average Voronoi Partition

Sai Chen,Chaoyong Li,Shuo Zhuo 제어로봇시스템학회 2017 제어로봇시스템학회 국제학술대회 논문집 Vol.2017 No.10

In this paper, we propose a distributed coverage algorithm for a group of UAVs to cover a convex region with average Voronoi partition which aims to ensure the areas of all Voronoi partitions are identical. The proposed algorithm iteratively updates the Voronoi partition through local information exchange with neighbors, and then moves along the computed direction. Different from existing results, the proposed algorithm could make the area difference infinitely small in theory to achieve indeed average area coverage. Simulation results are provided to illustrate the effectiveness of the proposed algorithm.

Multi-fidelity modeling and analysis of a pressurized vessel-pipe-safety valve system based on MOC and surrogate modeling methods

Song Xueguan,Li Qingye,Liu Fuwen,Zhou Weihao,Zong Chaoyong 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.8

A pressurized vessel-pipe-safety valve (PVPSV) combination is a commonly used configuration in nuclear power plants, and a good numerical model is essential for the system design, sizing and performance optimization. However, owing to the large-scale and cross-scale features, it is still a challenge to build a system level numerical model with both high accuracy and efficiency. To overcome this, a novel system level modeling method which can synthesize the advantages of various models is proposed in this paper. For system modeling, the analytical approach, the method of characteristics (MOC) and the surrogate model approach are respectively adopted to predict the dynamics of the pressure vessel, the connecting pipe and the safety valve, and different models are connected through data interfaces. With this system model, dynamic simulations were carried out and both the stable and the unstable system responses were obtained. For the model verification purpose, the simulation results were compared with those obtained from experiments and full CFD simulations. A good agreement and a better efficiency were obtained, verifying the ability of the model and the feasibility of the modeling method proposed in this paper