Search

In view of the difficulty of fault prediction for aviation hydraulic pumps and the poor real-time performance of state monitoring in practical applications, a hydraulic pump pressure signal prediction method is proposed to accomplish the monitoring and prediction of the health status of hydraulic pumps in advance. First, based on the on-line real-time acquisition of time series flight parameters and pressure signal data, the chaotic characteristics of the system are analyzed using chaos theory, so that the time series pressure signal is predictable. Second, phase space reconstruction (PSR) of the one-dimensional time series data is conducted. The embedding dimension $m$ and time delay $\tau $ are obtained by the C-C method. The reconstructed matrix is used as the training set and test set of the support vector regression (SVR) algorithm model according to a certain proportion, and the genetic algorithm (GA) is then used to optimize the parameters of the SVR model. Finally, the SVR model optimized by the genetic algorithm based on phase space reconstruction (PSR-GA-SVR) is used to test the test set data. The results show that the prediction accuracy of the proposed method is higher than that of the BP neural network based on phase space reconstruction (PSR-BPNN) and the SVR model based on phase space reconstruction (PSR-SVR). Relative to PSR-BPNN and PSR-SVR, PSR-GA-SVR produces a minimum mean square error (MSE) reduced by 73.40% and 68.0%, respectively, and a mean absolute error (MAE) decreased by 90.41% and 90.87%, respectively. The confidence level for PSR-GA-SVR was increased, and the coefficient of determination was greater than 0.98.

// Xin-Zu Chen 1, 2, * , Shao-Yong Wang 1, 3, * , Yin-Su Wang 4 , Zi-Han Jiang 4 , Wei-Han Zhang 1, 2 , Kai Liu 1, 2 , Kun Yang 1, 2 , Xiao-Long Chen 1, 2 , Lin-Yong Zhao 1, 2 , Meng Qiu 5 , Hong-Feng Gou 5 , Zong-Guang Zhou 1, 6 and Jian-Kun Hu 1, 2 1 Department of Gastrointestinal Surgery, West China Hospital, Sichuan University, Chengdu, China 2 Institute of Gastric Cancer, State Key Laboratory of Biotherapy/Collaborative Innovation Center of Biotherapy, West China Hospital, Sichuan University, Chengdu, China 3 Department of Gastrointestinal Surgery, Guizhou Provincial People's Hospital, Guiyang, China 4 Faculty of Medicine, West China Medical School, Sichuan University, Chengdu, China 5 Department of Medical Oncology, Cancer Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China 6 Institute of Digestive Surgery, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China * These authors equally contributed to this work and are co-first authors Correspondence to: Jian-Kun Hu, email: hujkwch@126.com Keywords: gastric cancer, laparoscopy, gastrectomy, survival, surgical oncology Received: November 14, 2016 Accepted: March 30, 2017 Published: April 10, 2017 ABSTRACT Objectives: The safety and surgical oncology of laparoscopy-assisted total gastrectomy (LATG) remain inconclusive and challenging. This study aimed to compare the short-term and long-term outcomes between LATG and open total gastrectomy (OTG) procedures. Results: In the all-included analyses, there were 69 patients in the LATG group and 268 in the OTG group. LATG was as safe as OTG without increasing postoperative morbidity and mortality. Stage imbalance might introduce differences in the numbers of harvested lymph nodes in LATG (34.4 ± 12.0) and OTG (40.9 ± 16.9), whereas 95.7% of patients underwent D2/D2+ dissection during the LATG procedure. After a median 31 months of follow-up, the overall survival outcomes were comparable between the LATG and OTG procedures (HR = 1.16, 95% CI 0.68–1.97). Sensitivity analysis found comparable node retrieval and stage-specific or treatment-specific overall survival. Materials and Methods: A retrospective case-control study was conducted among gastric cancer patients who underwent either LATG or OTG with curative intention between June 2006 and December 2015. Data retrieval was based on the Surgical Gastric Cancer Patient Registry in the West China Hospital. The primary outcome was overall survival. The secondary outcomes were postoperative complication incidence and severity, operation duration, blood loss, number of harvested lymph nodes, and postoperative hospital stay. Matched pairwise case-control comparisons were performed as a sensitivity analysis. Conclusions: LATG by experienced surgeons possibly has comparable short-term surgical outcomes and long-term survival outcomes compared with OTG for gastric cancer patients. However, high-quality RCTs are necessary before confirmative judgment and recommendation as an optional treatment in general practice.

The line replaceable unit (LRU) is a direct carrier of the fighter’s field replacement and maintenance strategy. It is reasonably and accurately divided into modules, which can quickly locate the fault location, reduce maintenance support time, and improve the efficiency of maintenance support Improve combat effectiveness. Aiming at the problem of the LRU division method in the aircraft design stage, this paper proposes an FSMC aircraft LRU division method based on function-structure-maintainability-coupling, comprehensively uses fuzzy clustering and other methods to evaluate and analyse the LRU division scheme, and compare different LRU schemes Use availability of the aircraft to perform simulation analysis. The research results show that the established on-site replaceable unit evaluation model can solve the problem of fighter aircraft LRU division schemes in the context of actual combat, and provide model support and empirical reference for further research on aircraft LRU division design research.