A PHASE-PLANE TRAJECTORY VECTOR-BASED METHOD

Critical Machines (CMs) identification is the first and most important step of Equivalent-Single Machine Infinite Bus (E-SMIB) based methods such as EEAC and SMIE for transient stability assessment and control. This paper presents a novel real-time CMs identification method based on the Phase-plane Trajectory Vector (PTV) with PMU information support. The proposed method overcomes the drawbacks of conventional CMs identification methods and enables to track the change of CMs during the dynamic process. Only two sample points of all generators from PMUs are required to obtain the PTVs at each moment and the computation of feature matrix, as well as the k-means clustering, is fast and accurate. The application of the PTV based method is verified through cases study in IEEE 39 bus New England power system. Results are compared well with those obtained by conventional methods

Dynamic Coherency Real-time Identification for Controlled Islanding

Controlled islanding often acts as the last resort against a severe blackout. Generator coherency is the primary constraint to determine an effective controlled islanding strategy. This paper proposes a scheme to identify the dynamic coherency of generators for controlled islanding. The generator coherency is identified based on the Phase-plane Trajectory Vectors (PTVs) on the Phase Plane for Generators (PPG). Then a Phase Plane for Buses (PPB) is proposed to assign the non-generator buses to coherent generator groups following the minimum distance principle. The separated islands are formed by disconnecting certain transmission lines according to the identified coherent generators and areas. The case studies in IEEE 39-bus 10-machine power system show that the proposed scheme can not only adapt to different disturbances and changes of system conditions and network topology but also succeed in identifying the generator coherency at different times and developing proper islanding strategy according to current system states

Embedded Palmprint Recognition System Using OMAP 3530

We have proposed in this paper an embedded palmprint recognition system using the dual-core OMAP 3530 platform. An improved algorithm based on palm code was proposed first. In this method, a Gabor wavelet is first convolved with the palmprint image to produce a response image, where local binary patterns are then applied to code the relation among the magnitude of wavelet response at the ccentral pixel with that of its neighbors. The method is fully tested using the public PolyU palmprint database. While palm code achieves only about 89% accuracy, over 96% accuracy is achieved by the proposed G-LBP approach. The proposed algorithm was then deployed to the DSP processor of OMAP 3530 and work together with the ARM processor for feature extraction. When complicated algorithms run on the DSP processor, the ARM processor can focus on image capture, user interface and peripheral control. Integrated with an image sensing module and central processing board, the designed device can achieve accurate and real time performance

Experimental Research on the Dynamic Characteristics of Offshore Wind Turbine Model Under the Action of Highly Nonlinear Waves

[Introduction] Monopile foundation is currently the most widely used support structure for offshore wind farms. For offshore wind farms in the medium water depth area such as Dafeng, Binhai and Sheyang in China, the design waves are very close to the wave breaking limit. Compared with the traveling wave, the focused waves can form an impact force on the pile column in a short time, which is larger than the conventional wave force, and undermines the operational performance and fatigue life of the offshore wind turbines. [Method] In this paper, NREL 5 MW monopile wind turbine model tests were carried out to investigate the hydrodynamic response of large offshore wind turbines to highly nonlinear waves and other harsh waves in combination with the marine environmental conditions of China's eastern coastal wind farms, focusing on exploring the test techniques for monopile wind turbines, and the mechanism of interaction between focused waves and monopiles under the action of focused waves. [Result] The results show that, the horizontal wave force on the pile foundation, which is significantly transient, will suddenly increase when the focused waves act on the monopile foundation, and receive the reverse impact force at the trough of focused wave fluctuation. [Conclusion] The results are of high theoretical value and have engineering prospect for the safe operation of monopile foundation

Knowledge and Attitudes Towards Obesity and Bariatric Surgery in Chinese Nurses

Abstract Background Obesity has become a global epidemic. Surgical treatment of obesity and metabolic disorders in China is increasing rapidly, but it is still a new discipline even to health professionals. As an important member of the multidisciplinary team, the knowledge and attitudes of nurses provide crucial health care to the patients and support to surgeons. Objectives To study the Chinese nurses' knowledge of obesity and metabolic disorders, and attitudes towards bariatric surgery and to improve their capability of work in this new discipline. Methods This is a multicenter study, with the questionnaire distributed to cooperative hospitals in the form of an electronic questionnaire by the First Affiliated Hospital of Jinan University in April 2018. A questionnaire was designed to investigate nurses' demographic, knowledge, and attitude towards obesity, weight loss, and bariatric surgery. Results A total of 5311 questionnaires were received, with an effective rate of 91.8% (4878 questionnaires); 65.2% of nurses had a normal BMI. Nurses generally had a high knowledge of obesity and related cardiovascular diseases (98.6%) and type 2 diabetes mellitus (90.2%). However, there was a lack of knowledge in other related aspects, for example its relations to carcinoma (49.5%), gastroesophageal reflux disease (40.1%), and psychological disorders (49.1%), which are controversial issues in bariatric surgery. It was found that education (p < 0.05) had an important influence to nurses' knowledge about the comorbidities of obesity. Female nurses had a higher tendency to choose weight loss than males, but male nurses did physical exercise more frequently than females (p < 0.05). Their acceptance of safety (25.1%) and efficacy (22.9%) of bariatric surgery is low, with concerns predominantly about postoperative complications and adverse effects. Surgical nurses had a more optimistic attitude towards surgery (p < 0.05). Conclusions Chinese nurses have poor knowledge of obesity-related metabolic disorders and also have poor acceptance of surgical treatment modalities. Our findings suggest that it is crucial to enhance the continuing education of Chinese nurses for obesity, metabolic disorders, and bariatric surgery

Biomechanical analysis of spinal cord injury during scoliosis correction surgery

Introduction: Surgical correction is a common treatment for severe scoliosis. Due to the significant spinal deformation that occurs with this condition, spinal cord injuries during corrective surgery can occur, sometimes leading to paralysis.Methods: Such events are associated with biomechanical changes in the spinal cord during surgery, however, their underlying mechanisms are not well understood. Six patient-specific cases of scoliosis either with or without spinal complications were examined. Finite element analyses (FEA) were performed to assess the dynamic changes and stress distribution of spinal cords after surgical correction. The FEA method is a numerical technique that simplifies problem solving by replacing complex problem solving with simplified numerical computations.Results: In four patients with poor prognosis, there was a concentration of stress in the spinal cord. The predicted spinal cord injury areas in this study were consistent with the clinical manifestations of the patients. In two patients with good prognosis, the stress distribution in the spinal cord models was uniform, and they showed no abnormal clinical manifestations postoperatively.Discussion: This study identified a potential biomechanical mechanism of spinal cord injury caused by surgical correction of scoliosis. Numerical prediction of postoperative spinal cord stress distribution might improve surgical planning and avoid complications

A Trial on the Current Situation of Cross-Strait Relations, Whether the Issue May Evolve from Friction to War

This essay focuses on the current state of cross-strait relations and whether the issue may evolve from friction to war. In 2022, after Russia declared war on Ukraine, the world is again in the shadow of war, and cross-strait relations have been a powder keg in the international community. Taiwan, as a country with its legislature, political party and complete state system, but not recognized by the international community. It has long been at odds with the PRC, which claimed Taiwan as part of its own. Since the KMT stepped down and the DPP took power in 2016, Tsai Ing-wen (Taiwan’s de facto leader) has denied the 1992 Consensus, and with Pelosi’s visit to Taiwan, increasing friction in cross-strait relations, and PLA air forces operating across the centre line of the strait, there is growing concern among the world’s population that cross-strait relations will break down and degenerate into war. The purpose of this paper is to discuss the possibility of cross-strait relations from mutual condemnation to actual conflict in terms of the history of cross-strait relations, the current development of Taiwan and China, and the attitudes of the aborigines on both sides of the Taiwan Strait. It also discusses the current situation of cross-strait relations, the future development of the two places, and the attitudes of several Taiwanese and mainlanders toward the cross-strait conflict

Development and Application of a High-Precision Portable Digital Compass System for Improving Combined Navigation Performance

There are not many high-precision, portable digital compass solutions available right now that can enhance combined navigation systems’ overall functionality. Additionally, there is a dearth of writing about these products. This is why a tunnel magnetoresistance (TMR) sensor-based high-precision portable digital compass system is designed. First, the least-squares method is used to compensate for compass inaccuracy once the ellipsoid fitting method has corrected manufacturing and installation errors in the digital compass system. Second, the digital compass’s direction angle data is utilized to offset the combined navigation system’s mistake. The final objective is to create a high-performing portable TMR digital compass system that will enhance the accuracy and stability of the combined navigation system (abbreviated as CNS). According to the experimental results, the digital compass’s azimuth accuracy was 4.1824° before error compensation and 0.4580° after it was applied. The combined navigation system’s path is now more accurate overall and is closer to the reference route than it was before the digital compass was added. Furthermore, compared to the combined navigation route without the digital compass, the combined navigation route with the digital compass included is more stable while traveling through the tunnel. It is evident that the digital compass system’s design can raise the integrated navigation system’s accuracy and stability. The integrated navigation system’s overall performance may be somewhat enhanced by this approach

A Phase-plane Based Dynamic Coherency Real-time Identification Scheme for Controlled Islanding

Controlled islanding often acts as the last resort against a severe blackout. Generator coherency is the primary constraint to determine an effective controlled islanding strategy. This paper proposes a scheme to identify the dynamic coherency of generators for controlled islanding. The generator coherency is identified based on the Phase-plane Trajectory Vectors (PTVs) on the Phase Plane for Generators (PPG). Then a Phase Plane for Buses (PPB) is proposed to assign the non-generator buses to coherent generator groups following the minimum distance principle. The separated islands are formed by disconnecting certain transmission lines according to the identified coherent generators and areas. The case studies in IEEE 39-bus 10-machine power system show that the proposed scheme can not only adapt to different disturbances and changes of system conditions and network topology but also succeed in identifying the generator coherency at different times and developing proper islanding strategy according to current system states

Experiment of aerosol-release time for a novel automatic metered dose inhaler

The objective of this study was to evaluate the aerosol-release time in the development of a new automatic adapter for metered dose inhaler. With this device, regular manually operated metered dose inhalers become automatic. During the study, an inhalation simulator was designed and tested with the newly developed mechatronic system. By adjusting the volume and the pressure of the vacuum tank, most human inhalation waveforms were able to simulate. As an example, regular quick-deep and slow-deep waveforms were matched within reasonable accuracy. Finally, with the help of dynamic image processing, the aerosol-release time (T r ) was carefully measured and fully discussed, including the switch-on time (T s ), the mechatronics-hysteresis (T m ) and the intentional-delay (T i ). Under slow-deep inhalation condition which is suitable for metered dose inhaler medicine delivery, the switch-on flow-rate could reach as low as 10 L/min, and the corresponding switch-on time was approximately 0.20 s. While the mechatronics-hysteresis depended on the brand of metered dose inhaler, assuming there was no intentional-delay, the aerosol-release time could be as low as 0.40 and 0.60 s, respectively, for two commercially available metered dose inhalers studied in this article. Therefore, this newly developed mechatronic adapter system could ensure aerosol-release time (T r ) within satisfactory range for metered dose inhalers