285 research outputs found
Yu zhi pei wen yun fu
No full text[張玉書...[et al.]奉敕撰].綫裝, 20函.框16.5x11.8公分, 12行25字, 小字雙行同, 無界行. 白口, 單黑魚尾, 四周雙邊. 版心上鐫題名, 中鐫卷次, 下鐫葉次.出書年據序.Xian zhuang, 20 han.Kuang 16.5 x 11.8 gong fen, 12 hang 25 zi, xiao zi shuang hang tong, wu jie xing. Bai kou, dan hei yu wei, si zhou shuang bian. Ban xin shang juan ti ming, zhong juan juan ci, xia juan ye ci.Chu shu nian ju xu.[Zhang Yushu ...[et al.] feng chi zhuan]
A hierarchical control scheme for multiple aerial vehicle transportation systems with uncertainties and state/input constraints
No full textMultiple aerial vehicles have the potential to transport payload in any direction and with any orientation in Special Euclidean Group. In this article, the control problem of the multiple aerial vehicle transportation system with uncertainties and state/input constraints is considered. The multiple aerial vehicles connect with the load via spherical pairs that coincide with the center of mass of the aerial vehicles. A hierarchical control scheme of such challenging complex systems is proposed. The outer loop is designed by a tube-based model predictive control in order to deal with uncertainties, state constraints and input boundedness, while the inner loop is designed by robust control technique which forces the attitude tracking error of the aircraft into robust invariant set. The attitude tracking error of the inner loop induces a difference between the commanded and the actual equivalent wrench acting on the load. Such difference is treated as the equivalent disturbance of the outer loop to guarantee the fulfillment of the state and input constraints. The hierarchical control structure simplifies the design procedure, while still preserves the convergence and feasibility of the overall controlled system under uncertainties, which are proved strictly in the paper. Numerical simulations on a six-quadrotor transportation system are conducted to demonstrate the performance of the proposed control scheme. A real-world prototype including three quadrotors is developed. The hardware-in-the-loop simulation on the prototype supports the real-time feasibility of the proposed scheme
Real-Time Multi-Modal Active Vision for Object Detection on UAVs Equipped With Limited Field of View LiDAR and Camera
No full textThis letter aims to solve the challenging problems in multi-modal active vision for object detection on unmanned aerial vehicles (UAVs) with a monocular camera and a limited Field of View (FoV) LiDAR. The point cloud acquired from the low-cost LiDAR is firstly converted into a 3-channel tensor via motion compensation, accumulation, projection, and up-sampling processes. The generated 3-channel point cloud tensor and RGB image are fused into a 6-channel tensor using an early fusion strategy for object detection based on a Gaussian YOLO network structure. To solve the low computational resource problem and improve the real-time performance, the velocity information of the UAV is further fused with the detection results based on an extended Kalman Filter (EKF). A perception-aware model predictive control (MPC) is designed to achieve active vision on our UAV. According to our performance evaluation, our pre-processing step improves other literature methods running time by a factor of 10 while maintaining acceptable detection performance. Furthermore, our fusion architecture reaches 94.6 mAP on the test set, outperforming the individual sensor networks by roughly 5%. We also described an implementation of the overall algorithm on a UAV platform and validated it in real-world experiments
Inter-seismic deformation field of the Ganzi-Yushu fault before the 2010 Mw 6.9 Yushu earthquake
No full textThe 14 April 2010 Mw 6.9 Yushu earthquake ruptured the northwestern segment of the Ganzi-Yushu fault in Qinghai Province, China. Using GPS data obtained from 1999 to 2007 in the vicinity of the Ganzi-Yushu fault, we estimate the slip rates of the Fenghuoshan and Ganzi-Yushu faults, and the northwestern segment of the Xianshuihe fault as 6.1 +/- 1.9, 6.6 +/- 1.5, and 9.7 +/- 0.7 mm/a for left lateral components, and 2.8 +/- 1.9, 1.7 +/- 1.6, and -2.0 +/- 0.9 mm/a for shortening components, respectively. The Maduo-Gande fault slips left laterally at a rate of about 1-2 mm/a, and similar to 3 mm/a sinistral shear motion is left unexplained, possibly caused by deformation across one or more unknown faults in the region. These results agree with geological estimates of the fault slip rates, and show a progressive increase of shear motion from northwest to southeast across segments of the Xianshuihe-Ganzi-Yushu fault zone, implying variation in transferring and absorbing deformation in different regions in and around the Tibetan plateau. (C) 2012 Elsevier B.V. All rights reserved.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000315613700013&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Geochemistry & GeophysicsSCI(E)EI4ARTICLE,SI138-14358
Mental Health Problems among the Survivors in the Hard-Hit Areas of the Yushu Earthquake
No full textBackground: On April 14, 2010, an earthquake registering 7.1 on the Richter scale shook Qinghai Province in southwest China. The earthquake caused numerous casualties and much damage. The epicenter, Yushu County, suffered the most severe damage. As a part of the psychological relief work, the present study evaluated the mental health statuses of the people affected and identified the mental disorder risk factors related to earthquakes
A framework to design interaction control of aerial slung load systems: transfer from existing flight control of under-actuated aerial vehicles
No full textThis paper establishes a framework within which interaction control is designed for the aerial slung load system composed of an underactuated aerial vehicle, a cable and a load. Instead of developing a new control law for the system, we propose the interaction control scheme by the controllers for under-actuated aerial systems. By selecting the deferentially flat output as the configuration, the equations of motion of the two systems are described in an identical form. The flight control task of the under-actuated aerial vehicle is thus converted into the control of the aerial slung load system. With the help of an admittance filter, the compliant trajectory is generated for the load subject to external interaction force. Moreover, the convergence of the whole system is proved by using the boundedness of the tracking error of vehicle attitude tracking as well as the estimation error of external force. Based on the developed theoretical results, an example is provided to illustrate the design algorithm of interaction controller for the aerial slung load via an existing flight controller directly. The correctness and applicability of the obtained results are demonstrated via the illustrative numerical example
Kangxi zi dian: [12 juan, fu bei kao, bu yi]. v.1
No full text總閱官張玉書, 陳廷敬.綫裝.匡19.6 x 13.8 公分, 小字16行24字, 間有大字, 白口, 四周雙邊, 單魚尾.出版年據序.有桂馥朱墨眉批.Xian zhuang.Kuang 19.6 x 13.8 gong fen, xiao zi 16 hang 24 zi, jian you da zi, bai kou, si zhou shuang bian, dan yu wei.Chu ban nian ju xu.You Gui Fu zhu mo mei pi.zong yue guan Zhang Yushu, Chen Tingjing
Orthopaedic injury analysis in the 2010 Yushu, China Earthquake
No full textObjective: By analysing the injuries of the orthopaedic wounded during the 2010 Yushu earthquake, we aim to provide useful medical information for the rational application and allocation of medical resources and better implementation of medical relief in earthquake-stricken areas. Patients and methods: Five hundred and eighty-two orthopaedic patients injured during the earthquake. The clinical data, injury conditions and epidemiological features (including age composition, gender ratio, distribution of injury, etc.) were collected and analysed. Results: Altogether 582 orthopaedic patients were analysed. The average age for all patients was 38.8 + 13.08 years (0-86 years). Adults accounted for 81.62%. There was no gender difference. The most common injuries included limb fractures, pelvic/acetabular fractures and spinal fractures. Fractures accompany with nerve injury were relatively low, only 17 patients account for 2.92%. Fractures complicated by crush syndrome were even lower, only 7 patients account for 1.20%. Conclusion: The patients who experienced fractures in the Yushu earthquake were mostly adults. This was correlated with population composition in Yushu area. This time all the orthopaedic injuries were relative mild with less complication as nerve injury or crush syndrome mainly because of the characteristics of the house structure in Yushu area. (c) 2011 Elsevier Ltd. All rights reserved.Critical Care MedicineEmergency MedicineOrthopedicsSurgerySCI(E)PubMed1ARTICLE6886-8904
Remote sensing perspective in exploring the spatiotemporal variation characteristics and post-disaster recovery of ecological environment quality, a case study of the 2010 Ms7.1 Yushu earthquake
No full textNatural hazards usually cause heavy casualties and vast economic losses, as well as severe damage to the ecological environment. Quantitative and scientific evaluations of the ecological environment quality (EEQ) and its recovery trend after hazards can provide valuable insights for disaster risk reductions. This study takes the 2010 Ms7.1 Yushu earthquake as an example to explore the spatiotemporal changes and driving mechanisms of EEQ before and after the earthquake using remote sensing and GIScience. First, the Moderate-resolution Imaging Spectroradiometer (MODIS) data was selected to establish the remote sensing based ecological index (RSEI). Then, we analyzed the spatiotemporal characteristics of Yushu’s EEQ from 2001 to 2020 and explored spatial autocorrelation relationships. Last, the driving mechanism of EEQ recovery in Yushu was analyzed using the GeoDetector model. The main conclusions are as follows: (1) From the perspective of the RSEI time series, the EEQ in Yushu County was strongly negatively affected during the earthquake and recovered well after the earthquake. (2) Based on a spatial distribution analysis, it can be observed that the regions in Yushu with relatively high EEQ are primarily concentrated in the central and southern areas. Conversely, the northwestern and southeastern areas display relatively lower quality. Moreover, the EEQ in Yushu County has a strong correlation and clustering, as evidenced by Moran’s I value exceeding 0.7 over the years. (3) Based on the GeoDetector results, elevation and population were found to be the key driving factors affecting changes in post-disaster EEQ. The interaction between elevation and slope plays the most critical role in the process of ecological recovery. This study provides a theoretical basis for the evolution of the post-disaster ecological environment in Yushu County and helps decision-makers better balance the relationship between social development and environmental protection in disaster management and urban planning. It also provides useful reference and guidance for future ecological protection and recovery under similar disasters
Post-Traumatic Stress and School Adaptation in Adolescent Survivors Five Years after the 2010 Yushu Earthquake in China
No full text(1) Background: The devastating Ms 7.1 earthquake struck Yushu city, China, in 2010, leading to serious consequences and damage in the central Tibetan Plateau. This study aimed to assess school adaptation and post-traumatic stress disorder (PTSD) symptoms of adolescent survivors five years after the Yushu earthquake. (2) Methods: A large-scale, school-based mental health survey was conducted 5 years after the earthquake among Tibetan students in the city of Yushu using the Adolescent’s School Adaptation Scale (ASAS) and the PTSD Checklist. (3) Results: A total of 1976 questionnaires were collected. A total of 30.7% of Tibetan adolescents had poor school adaptation and 19.5% were estimated as having probable PTSD. Logistic regression showed that females (OR = 0.73, 95% CI: 0.60–0.89), senior students (OR = 0.48, 95% CI: 0.39–0.59), and those who participated in post-disaster reconstruction (OR = 0.68, 95% CI: 0.54–0.85) were less likely to have poor school adaptation, while a positive association was observed among those buried under a collapsed building (OR = 1.47, 95% CI: 1.04–2.09) and those who experienced bereavement (OR = 1.77, 95% CI: 1.27–2.45). Students who had experienced bereavement were also more likely to have PTSD (OR = 1.60, 95% CI: 1.12–2.28). (4) Conclusions: The post-traumatic effects of the Yushu earthquake on Tibetan adolescents were severe and long-lasting. Sustainable long-term mental health services to help adolescents to restructure their mental health are necessary
- …
