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predictive Maintenance of Manned Spacecraft Through Remaining Useful Life Estimation Technique

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Aerospace China 2018年第3期19卷 3-10页

作者： CHEN Runfeng YANG Hong Institute of Manned Space System Engineering Beijing 100094

Manned spacecraft pose challenges in terms of extremely high safety and reliability, and with the growth of system complexity and longer on-orbit operation time, the traditional management mode, such as monitoring the threshold of parameter passively, is difficult to meet the required safety standards. predictive maintenance, which analyzes the system heath trend and estimates remaining useful life(RUL) to establish maintenance strategies ahead of time before failure occurs, is a new mode to approach maintenance tasks. Here, a predictive maintenance strategy for complex manned spacecraft is proposed based on the remaining useful life estimation technique. Firstly, a health index is established based on an abundance of telemetry data, reflecting the system's current health state. Secondly, we map the health index to the remaining useful life through system degradation modelling, taking into consideration both the system's stochastic deterioration and uncertainty. The maintenance and management strategies are then made based on the calculated distribution of RUL time. Finally, a case study on Chinese space station energy system predictive maintenance is presented.

关键词： remaining useful life predictive maintenance Chinese space station

predictive Potential of FDG-PET/CT for Histological Transformation in Patients with Indolent Lymphoma

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Advances in Molecular Imaging 2014年第1期4卷 1-10页

作者： Peter E. Blase Pieternel C. M. Pasker-de Jong Anton Hagenbeek Rob Fijnheer Marie J. de Haas John M. H. de Klerk Department of Haematology Academical Medical Centre Amsterdam The Netherlands Department of Internal medicine Meander Medical Centre Amersfoort The Netherlands Department of Meander Academy Meander Medical Centre Amersfoort The Netherlands Department of Nuclear medicine Meander Medical Centre Amersfoort The Netherlands

Backgrounds and Purpose—In indolent non-Hodgkin lymphoma, histological transformation is a dramatic event which reduces the prognosis significantly. SUVmax values from FDG-PET/CT help differentiate between aggressive and indolent lymphomas, and transformed indolent lymphomas also show an increased FDG uptake. Possibly FDG uptake increases early in the clinical course and could predict histological transformation. Our objective was to predict histological transformation in indolent lymphomas from initial staging FDG-PET/CT. Patients and Methods—A retrospective study was performed. Patients with biopsy-proven indolent lymphoma who had had initial staging FDG-PET/CT were included. Qualitative (foci compared with FDG uptake liver) and semiquantitative (SUVmax-value per focus) analyses were performed of all abnormal foci. Patient characteristics and outcome were evaluated. Results—We included 88 patients, 5 of whom developed a histological transformation. Semiquantitative analysis showed a relation between maximum standardized uptake value and histological transformation (odds ratio 1.25, 95% CI 1.024 - 1.513). Qualitative analysis showed a negative predictive relation of FDG uptake less than or equal to liver in the occurrence of histological transformation. Transformation-free survival was 100% over 30 months in those with FDG uptake lower than or equal to liver. More FDG uptake than liver showed transformation-free survival of 88% over 30 months. Conclusion—Qualitative analysis of staging FDG-PET/CT in indolent lymphomas could be useful to rule out transformation in the next 30 months. In our study, semiquantitative analysis was statistically significantly associated with histological transformation and maximum standardized uptake value. However, because of the small number of patients, cautious interpretation of the results is warranted. More studies are needed to investigate the role of staging PET/CT in patient with indolent non-Hodkin lymphoma in the prediction of transformation.

关键词： Indolent Lymphoma Transformation PET/CT predictive Value

predictive Factors for Persistent Pain and Poor Recovery of Health Status 1 Year after Whiplash Injury (Quebec Grade 1 and 2): Results from the ESPARR Cohort

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Pain Studies and Treatment 2014年第2期2卷 36-49页

作者： Inès Khati Laetitia Chossegros Pierrette Charnay Hélène Tardy Anne-Laure Perrine Bernard Laumon Martine Hours Unité Mixte de Recherche Epidémiologique et de Surveillance Transport Travail Environnement (UMRESTTE) N°T9405: Université de Lyon Lyon France IFSTTAR UMRESTTE Bron France Unité Mixte de Recherche Epidémiologique et de Surveillance Transport Travail Environnement (UMRESTTE) N°T9405: Université de Lyon Lyon France IFSTTAR UMRESTTE Bron France Institut National de Veille Sanitaire Saint Maurice France

Background: A large number of studies have addressed whiplash injury, and many meta-analyses have sought to highlight chronicity factors;the implicated processes, however, remain a matter of debate. The present study used data from the ESPARR cohort (an on-going prospective study of a representative cohort of road accident victims in the Rh?ne administrative département of France). The objectives were to describe the consequences of whiplash injury and to determine prognostic factors for poor recovery and persistent pain at 1 year post-accident. Methods: The cohort included 255 “pure” whiplash victims, 173 of whom responded to the 1-year follow-up questionnaire. Correlations between explanatory variables and health and pain status were explored by modified Poisson regression to provide adjusted relative risk (RR) values. Results: Half of the victims had not fully recovered health status by 1 year. The main factor associated with non-recovery was pain (RR = 1.3;1.0-1.7). A birth in the family preceding the accident emerged as another factor (RR=1.5;1.2-1.9). Victims responsible for their accident were twice as likely to report being free of pain as those not responsible (RR = 0.5;0.3-0.8). No correlation emerged with accident-related characteristics or PTSD. Conclusions: The present results extend our understand- ing of whiplash injury. Residual pain is the fundamental factor causing whiplash victims to feel that they have not recovered good health. Our findings suggest this may be bound up with physical factors (gender susceptibility);external factors such as having to carry weights (such as a baby) and with perceiving oneself as a victim are not incompatible with this hypothesis.

关键词： Whiplash One Year-Follow-up Recovered Health Pain predictive Factor

predictive Value of Clinical and Laboratory Parameters for Overt Bone Marrow Metastasis in Patients with Solid Malignancy

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Journal of Cancer Therapy 2017年第8期8卷 773-784页

作者： Kalman Filanovsky Edit Feldberg Edward B. Miller Lev Shvidel Department of Hematology Kaplan Medical Center Hadassah and Hebrew University Medical School Jerusalem Israel Department of Pathology Kaplan Medical Center Hadassah and Hebrew University Medical School Jerusalem Israel Department of Internal Medicine D Kaplan Medical Center Hadassah and Hebrew University Medical School Jerusalem Israel

Bone marrow (BM) metastases are known to worsen the outcome in patients with malignancies and alter the choice of the treatment regimen. In an attempt to identify routine parameters for the prediction of BM metastasis we evaluated the clinical and laboratory data of 103 patients with metastatic solid tumors. We also assessed which of these factors appeared to influence survival. Three laboratory abnormalities were found to be predictive of metastasis on BM biopsy: thrombocytopenia 9/L OR 14.4;p = 0.02;hypocellular or dry tap aspirate OR 7.0;p = 0.02 and high serum alkaline phosphatase OR 6.5;p = 0.03. Three additional factors were found to be associated with deceased survival. Thrombocytopenia was associated with decreased survival from a median of 0.8 months to 4.1 months, p < 0.0001. Serum LDH levels more than twice the upper limit of normal were also reduced survival from 1.8 months versus 4.7 months, p = 0.03. Finally, the initial diagnosis of malignancy by bone marrow examination was associated with reduced survival from 1.8 months vs. 4.0 months, p = 0.03 in individuals where BM metastases were not the presenting feature of malignancies. Use of these simple clinical parameters may help in the early diagnosis of bone marrow metastases and improve clinical approach.

关键词： Bone Marrow Metastasis predictive Factors Survival Solid Tumor

predictive Prefetching for Parallel Hybrid Storage Systems

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International Journal of Communications, Network and System Sciences 2015年第5期8卷 161-180页

作者： Maen M. Al Assaf King Abdullah II School for Information Technology The University of Jordan Amman Jordan

In this paper, we present a predictive prefetching mechanism that is based on probability graph approach to perform prefetching between different levels in a parallel hybrid storage system. The fundamental concept of our approach is to invoke parallel hybrid storage system’s parallelism and prefetch data among multiple storage levels (e.g. solid state disks, and hard disk drives) in parallel with the application’s on-demand I/O reading requests. In this study, we show that a predictive prefetching across multiple storage levels is an efficient technique for placing near future needed data blocks in the uppermost levels near the application. Our PPHSS approach extends previous ideas of predictive prefetching in two ways: (1) our approach reduces applications’ execution elapsed time by keeping data blocks that are predicted to be accessed in the near future cached in the uppermost level;(2) we propose a parallel data fetching scheme in which multiple fetching mechanisms (i.e. predictive prefetching and application’s on-demand data requests) can work in parallel;where the first one fetches data blocks among the different levels of the hybrid storage systems (i.e. low-level (slow) to high-level (fast) storage devices) and the other one fetches the data from the storage system to the application. Our PPHSS strategy integrated with the predictive prefetching mechanism significantly reduces overall I/O access time in a hybrid storage system. Finally, we developed a simulator to evaluate the performance of the proposed predictive prefetching scheme in the context of hybrid storage systems. Our results show that our PPHSS can improve system performance by 4% across real-world I/O traces without the need of using large size caches.

关键词： predictive Prefetching Probability Graph Parallel Storage Systems Hybrid Storage System

hENT1 expression is predictive of gemcitabine outcome in pancreatic cancer: A systematic review

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World Journal of Gastroenterology 2014年第26期20卷 8482-8490页

作者： Stina Nordh Daniel Ansari Roland Andersson Department of Surgery Clinical Sciences LundLund University and Sk?ne University Hospital

High human equilibrative nucleoside transporter 1(hENT1)-expression has shown a survival benefit in pancreatic cancer patients treated with gemcitabine in several studies.The aim of this systematic review was to summarize the results and try to assess the predictive value of hENT1 for determining gemcitabine outcome in pancreatic cancer.Relevant articles were obtained from PubMed,Embase and Cochrane databases.Studies evaluating hENT1-expression in pancreatic tumor cells from patients treated with gemcitabine were selected.Outcome measures were overall survival,disease-free survival(DFS),toxicity and response rate.The database searches identified 10 studies that met the eligibility criteria,and a total of 855 patients were included.Nine of 10 studies showed a statistically significant longer overall survival in univariate analyses in patients with high hENT1-expression compared to those with low expression.In the 7 studies that reported DFS as an outcome measure,6 had statistically longer DFS in the high hENT1 groups.Both toxicity and response rate were reported in only 2 articles and it was therefore hard to draw any major conclusions.This review provides evidence that hENT1 is a predictive marker for pancreatic cancer patients treated with gemcitabine.Some limitations of the review have to be taken into consideration,the majority of the included studies had a retrospective design,and there was no standardized scoring protocol for hENT1-expression.

关键词： Pancreatic cancer Gemcitabine hENT1 predictive Sur

Assessment of a predictive score for pulmonary complications in cancer patients after esophagectomy

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World Journal of Emergency Medicine 2016年第1期7卷 44-49页

作者： Xue-zhong Xing Yong Gao Hai-jun Wang Shi-ning Qu Chu-lin Huang Hao Zhang Hao Wang Quan-hui Yang Department of Intensive Care Unit Cancer Hospital Chinese Academy of Medical Sciences and Peking Union Medical College

BACKGROUND:Esophagectomy is a very important method for the treatment of resectable esophageal cancer,which carries a high rate of morbidity and mortality.This study was undertaken to assess the predictive score proposed by Ferguson et al for pulmonary complications after esophagectomy for patients with cancer.METHODS:The data of patients who admitted to the intensive care unit after transthoracic esophagectomy at Cancer Hospital of Chinese Academy of Medical Sciences and Peking Union Medical College between September 2008 and October 2010 were retrospectively reviewed.RESULTS:Two hundred and seventeen patients were analyzed and 129(59.4%)of them had postoperative pulmonary complications.Risk scores varied from 0 to 12 in all patients.The risk scores of patients with postoperative pulmonary complications were higher than those of patients without postoperative pulmonary complications(7.27±2.50 vs.6.82±2.67;P=0.203).There was no significant difference in the incidence of postoperative pulmonary complications as well as in the increase of risk scores(χ2=5.477,P=0.242).The area under the curve of predictive score was0.539±0.040(95%CI 0.461 to 0.618;P=0.324)in predicting the risk of pulmonary complications in patients after esophagectomy.CONCLUSION:In this study,the predictive power of the risk score proposed by Ferguson et al was poor in discriminating whether there were postoperative pulmonary complications after esophagectomy for cancer patients.

关键词： Respiratory insufficiencty Esophagectomy predictive

predictive value of HATCH score on atrial fibrillation recurrence post radiofrequency catheter ablation

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China Medical Abstracts(Internal Medicine) 2012年第4期29卷 216-217页

作者：缪丹丹 Dept Cardiol 1st Affil HospDalian Med Univ

Objective To determine the predictive value of HATCH score on recurrence of atrial fibrillation(AF) after radiofrequency catheter ablation (RFCA). Methods The data of 123 consecutive AF patients(74 paroxysmal and 49 p... 详细信息

关键词： fibrillation recurrence radiofrequency paroxysmal ablation persistent consecutive predictive department seconds

The Design of Output Feedback Distributed Model predictive Controller for a Class of Nonlinear Systems

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Applied Mathematics 2017年第12期8卷 1832-1850页

作者： Baili Su Yingzhi Wang College of Engineering Qufu Normal University Rizhao China

For a class of nonlinear systems whose states are immeasurable, when the outputs of the system are sampled asynchronously, by introducing a state observer, an output feedback distributed model predictive control algorithm is proposed. It is proved that the errors of estimated states and the actual system's states are bounded. And it is guaranteed that the estimated states of the closed-loop system are ultimately bounded in a region containing the origin. As a result, the states of the actual system are ultimately bounded. A simulation example verifies the effectiveness of the proposed distributed control method.

关键词： Nonlinear Systems Distributed Model predictive Control State Observer Output Feedback Asynchronous Measurements