AIM:To investigate national trends in distal pancreatectomy(DP) through query of three national patient care databases.METHODS:From the Nationwide Inpatient Sample(NIS,2003-2009),the National Surgical Quality Improvem...AIM:To investigate national trends in distal pancreatectomy(DP) through query of three national patient care databases.METHODS:From the Nationwide Inpatient Sample(NIS,2003-2009),the National Surgical Quality Improvement Project(NSQIP,2005-2010),and the Surveillance Epidemiology and End Results(SEER,2003-2009) databases using appropriate diagnostic and procedural codes we identified all patients with a diagnosis of a benign or malignant lesion of the body and/or tail of the pancreas that had undergone a partial or distal pancreatectomy.Utilization of laparoscopy was defined in NIS by the International Classification of Diseases,Ninth Revision correspondent procedure code;and in NSQIP by the exploratory laparoscopy or unlisted procedure current procedural terminology codes.In SEER,patients were identified by the International Classification of Diseases for Oncology,Third Edition diagnosis codes and the SEER Program Code Manual,third edition procedure codes.We analyzed the databases with respect to trends of inpatient outcome metrics,oncologic outcomes,and hospital volumes in patients with lesions of the neck and body of the pancreas that underwent operative resection.RESULTS:NIS,NSQIP and SEER identified 4242,2681 and 11 082 DP resections,respectively.Overall,laparoscopy was utilized in 15%(NIS) and 27%(NSQIP).No significant increase was seen over the course of the study.Resection was performed for malignancy in 59%(NIS) and 66%(NSQIP).Neither patient Body mass index nor comorbidities were associated with operative approach(P = 0.95 and P = 0.96,respectively).Mortality(3% vs 2%,P = 0.05) and reoperation(4% vs 4%,P = 1.0) was not different between laparoscopy and open groups.Overall complications(10% vs 15%,P < 0.001),hospital costs [44 741 dollars,interquartile range(IQR) 28 347-74 114 dollars vs 49 792 dollars,IQR 13 299-73 463,P = 0.02] and hospital length of stay(7 d,IQR 4-11 d vs 7 d,IQR 6-10,P < 0.001) were less when laparoscopy was utilized.One and two year survival after resection for malignancy were unchanged over the course of the study(ductal adenocarinoma 1-year 63.6% and 2-year 35.1%,P = 0.53;intraductal papillary mucinous neoplasm and nueroendocrine 1-year 90% and 2-year 84%,P = 0.25).The majority of resections were performed in teaching hospitals(77% NIS and 85% NSQIP),but minimally invasive surgery(MIS) was not more likely to be used in teaching hospitals(15% vs 14%,P = 0.26).Hospitals in the top decile for volume were more likely to be teaching hospitals than lower volume deciles(88% vs 43%,P < 0.001),but were no more likely to utilize MIS at resection.Complication rate in teaching and the top decile hospitals was not significantly decreased when compared to non-teaching(15% vs 14%,P = 0.72) and lower volume hospitals(14% vs 15%,P = 0.99).No difference was seen in the median number of lymph nodes and lymph node ratio in N1 disease when compared by year(P = 0.17 and P = 0.96,respectively).CONCLUSION:There appears to be an overall underutilization of laparoscopy for DP.Centralization does not appear to be occurring.Survival and lymph node harvest have not changed.展开更多
The high accurate classification ability of an intelligent diagnosis method often needs a large amount of training samples with high-dimensional eigenvectors, however the characteristics of the signal need to be extra...The high accurate classification ability of an intelligent diagnosis method often needs a large amount of training samples with high-dimensional eigenvectors, however the characteristics of the signal need to be extracted accurately. Although the existing EMD（empirical mode decomposition） and EEMD（ensemble empirical mode decomposition） are suitable for processing non-stationary and non-linear signals, but when a short signal, such as a hydraulic impact signal, is concerned, their decomposition accuracy become very poor. An improve EEMD is proposed specifically for short hydraulic impact signals. The improvements of this new EEMD are mainly reflected in four aspects, including self-adaptive de-noising based on EEMD, signal extension based on SVM（support vector machine）, extreme center fitting based on cubic spline interpolation, and pseudo component exclusion based on cross-correlation analysis. After the energy eigenvector is extracted from the result of the improved EEMD, the fault pattern recognition based on SVM with small amount of low-dimensional training samples is studied. At last, the diagnosis ability of improved EEMD＋SVM method is compared with the EEMD＋SVM and EMD＋SVM methods, and its diagnosis accuracy is distinctly higher than the other two methods no matter the dimension of the eigenvectors are low or high. The improved EEMD is very propitious for the decomposition of short signal, such as hydraulic impact signal, and its combination with SVM has high ability for the diagnosis of hydraulic impact faults.展开更多
针对不同供电区域多类型终端用户对供电可靠性的差异化需求以及目前配网侧依据单一供电可靠率指标衡量用户供电可靠性的局限性,提出一种基于大数据挖掘的终端用户的供电需求划分方法。首先,进行终端用户差异化供电需求量化,构建终端用...针对不同供电区域多类型终端用户对供电可靠性的差异化需求以及目前配网侧依据单一供电可靠率指标衡量用户供电可靠性的局限性,提出一种基于大数据挖掘的终端用户的供电需求划分方法。首先,进行终端用户差异化供电需求量化,构建终端用户供电需求信息模型;然后,采用综合K-means与基于密度聚类(density-based spatial clustering of applications with noise,DBSCAN)的大数据挖掘进行终端用户的聚类,实现用户的分类;最后采用改进的灰色关联度实现区域内终端用户可靠性等级划分。通过对含多类型终端用户的供电区域仿真分析,结合对比方案分析,进一步验证所提出的基于大数据挖掘的终端用户的供电可靠性需求划分方法的有效性。展开更多
文摘AIM:To investigate national trends in distal pancreatectomy(DP) through query of three national patient care databases.METHODS:From the Nationwide Inpatient Sample(NIS,2003-2009),the National Surgical Quality Improvement Project(NSQIP,2005-2010),and the Surveillance Epidemiology and End Results(SEER,2003-2009) databases using appropriate diagnostic and procedural codes we identified all patients with a diagnosis of a benign or malignant lesion of the body and/or tail of the pancreas that had undergone a partial or distal pancreatectomy.Utilization of laparoscopy was defined in NIS by the International Classification of Diseases,Ninth Revision correspondent procedure code;and in NSQIP by the exploratory laparoscopy or unlisted procedure current procedural terminology codes.In SEER,patients were identified by the International Classification of Diseases for Oncology,Third Edition diagnosis codes and the SEER Program Code Manual,third edition procedure codes.We analyzed the databases with respect to trends of inpatient outcome metrics,oncologic outcomes,and hospital volumes in patients with lesions of the neck and body of the pancreas that underwent operative resection.RESULTS:NIS,NSQIP and SEER identified 4242,2681 and 11 082 DP resections,respectively.Overall,laparoscopy was utilized in 15%(NIS) and 27%(NSQIP).No significant increase was seen over the course of the study.Resection was performed for malignancy in 59%(NIS) and 66%(NSQIP).Neither patient Body mass index nor comorbidities were associated with operative approach(P = 0.95 and P = 0.96,respectively).Mortality(3% vs 2%,P = 0.05) and reoperation(4% vs 4%,P = 1.0) was not different between laparoscopy and open groups.Overall complications(10% vs 15%,P < 0.001),hospital costs [44 741 dollars,interquartile range(IQR) 28 347-74 114 dollars vs 49 792 dollars,IQR 13 299-73 463,P = 0.02] and hospital length of stay(7 d,IQR 4-11 d vs 7 d,IQR 6-10,P < 0.001) were less when laparoscopy was utilized.One and two year survival after resection for malignancy were unchanged over the course of the study(ductal adenocarinoma 1-year 63.6% and 2-year 35.1%,P = 0.53;intraductal papillary mucinous neoplasm and nueroendocrine 1-year 90% and 2-year 84%,P = 0.25).The majority of resections were performed in teaching hospitals(77% NIS and 85% NSQIP),but minimally invasive surgery(MIS) was not more likely to be used in teaching hospitals(15% vs 14%,P = 0.26).Hospitals in the top decile for volume were more likely to be teaching hospitals than lower volume deciles(88% vs 43%,P < 0.001),but were no more likely to utilize MIS at resection.Complication rate in teaching and the top decile hospitals was not significantly decreased when compared to non-teaching(15% vs 14%,P = 0.72) and lower volume hospitals(14% vs 15%,P = 0.99).No difference was seen in the median number of lymph nodes and lymph node ratio in N1 disease when compared by year(P = 0.17 and P = 0.96,respectively).CONCLUSION:There appears to be an overall underutilization of laparoscopy for DP.Centralization does not appear to be occurring.Survival and lymph node harvest have not changed.
基金Supported by National Natural Science Foundation of China(Grant Nos.51175511,61472444)Jiangsu Provincial Natural Science Foundation of China(Grant No.BK20150724)Pre-study Foundation of PLA University of Science and Technology,China(Grant No.KYGYZL139)
文摘The high accurate classification ability of an intelligent diagnosis method often needs a large amount of training samples with high-dimensional eigenvectors, however the characteristics of the signal need to be extracted accurately. Although the existing EMD（empirical mode decomposition） and EEMD（ensemble empirical mode decomposition） are suitable for processing non-stationary and non-linear signals, but when a short signal, such as a hydraulic impact signal, is concerned, their decomposition accuracy become very poor. An improve EEMD is proposed specifically for short hydraulic impact signals. The improvements of this new EEMD are mainly reflected in four aspects, including self-adaptive de-noising based on EEMD, signal extension based on SVM（support vector machine）, extreme center fitting based on cubic spline interpolation, and pseudo component exclusion based on cross-correlation analysis. After the energy eigenvector is extracted from the result of the improved EEMD, the fault pattern recognition based on SVM with small amount of low-dimensional training samples is studied. At last, the diagnosis ability of improved EEMD＋SVM method is compared with the EEMD＋SVM and EMD＋SVM methods, and its diagnosis accuracy is distinctly higher than the other two methods no matter the dimension of the eigenvectors are low or high. The improved EEMD is very propitious for the decomposition of short signal, such as hydraulic impact signal, and its combination with SVM has high ability for the diagnosis of hydraulic impact faults.
文摘针对不同供电区域多类型终端用户对供电可靠性的差异化需求以及目前配网侧依据单一供电可靠率指标衡量用户供电可靠性的局限性,提出一种基于大数据挖掘的终端用户的供电需求划分方法。首先,进行终端用户差异化供电需求量化,构建终端用户供电需求信息模型;然后,采用综合K-means与基于密度聚类(density-based spatial clustering of applications with noise,DBSCAN)的大数据挖掘进行终端用户的聚类,实现用户的分类;最后采用改进的灰色关联度实现区域内终端用户可靠性等级划分。通过对含多类型终端用户的供电区域仿真分析,结合对比方案分析,进一步验证所提出的基于大数据挖掘的终端用户的供电可靠性需求划分方法的有效性。
