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Multistage seismic damage constitutive model and parameter calibration of reinforced concrete columns
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作者 Xing Chenxi Shu Yiwei +1 位作者 Zhu Xiaojie Zhong Jian 《Journal of Southeast University(English Edition)》 EI CAS 2024年第4期386-395,共10页
The road traffic network contains a large number of bridges,and calculating bridge damage using refined models demands significant time and resources.Therefore,developing a rapid evaluation method for the seismic capa... The road traffic network contains a large number of bridges,and calculating bridge damage using refined models demands significant time and resources.Therefore,developing a rapid evaluation method for the seismic capacity of regular bridges has become a crucial scientific challenge.This study presents an approach in which the ductile column is represented by a single degree-of-freedom model with elastic-plastic constitutive characteristics.Utilizing an uncoupled multivariate power function model and a plastic hinge model,a multidimensional power function model for section hierarchical curvature is constructed.Subsequently,the seismic multistage damage constitutive model(SMSD-CM)of member hierarchy is deduced and calibrated through theoretical methods.This model efficiently derives the trilinear constitutive model of components by inputting several crucial parameters.The SMSD-CM accurately simulates the hysteretic curve and displacement time-history under actual seismic conditions and aligns well with pushover analysis results from tests.The efficiency,ease of operation,and accuracy make the model suitable for rapid evaluation of the seismic capacity of regular bridges within the road traffic network. 展开更多
关键词 moment-curvature analysis fragility analysis curvature ductility seismic multilevel damage trilinear model
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Wavelet analysis of pressure fluctuation signals in a gas-solid fluidized bed 被引量:8
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作者 甄玲 王晓萍 +2 位作者 黄海 陈伯川 黄春燕 《Journal of Zhejiang University Science》 CSCD 2002年第1期52-56,共5页
It has been shown that much dynamic information is hidden in the pressure fluctuation signals of a gas-solid fluidized bed. Unfortunately, due to the random and capricious nature of this signal, it is hard to realize ... It has been shown that much dynamic information is hidden in the pressure fluctuation signals of a gas-solid fluidized bed. Unfortunately, due to the random and capricious nature of this signal, it is hard to realize reliable analysis using traditional signal processing methods such as statistical analysis or spectral analysis, which is done in Fourier domain. Information in different frequency band can be extracted by using wavelet analysis. On the evidence of the composition of the pressure fluctuation signals, energy of low frequency (ELF) is proposed to show the transition of fluidized regimes from bubbling fluidization to turbulent fluidization. Plots are presented to describe the fluidized bed's evolution to help identify the state of different flow regimes and provide a characteristic curve to identify the fluidized status effectively and reliably. 展开更多
关键词 wavelet analysis pressure fluctuation multi\|resolution analysis fluidized bed ELF
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Fingerprint Liveness Detection Based on Multi-Scale LPQ and PCA 被引量:13
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作者 Chengsheng Yuan Xingming Sun Rui Lv 《China Communications》 SCIE CSCD 2016年第7期60-65,共6页
Fingerprint authentication system is used to verify users' identification according to the characteristics of their fingerprints.However,this system has some security and privacy problems.For example,some artifici... Fingerprint authentication system is used to verify users' identification according to the characteristics of their fingerprints.However,this system has some security and privacy problems.For example,some artificial fingerprints can trick the fingerprint authentication system and access information using real users' identification.Therefore,a fingerprint liveness detection algorithm needs to be designed to prevent illegal users from accessing privacy information.In this paper,a new software-based liveness detection approach using multi-scale local phase quantity(LPQ) and principal component analysis(PCA) is proposed.The feature vectors of a fingerprint are constructed through multi-scale LPQ.PCA technology is also introduced to reduce the dimensionality of the feature vectors and gain more effective features.Finally,a training model is gained using support vector machine classifier,and the liveness of a fingerprint is detected on the basis of the training model.Experimental results demonstrate that our proposed method can detect the liveness of users' fingerprints and achieve high recognition accuracy.This study also confirms that multi-resolution analysis is a useful method for texture feature extraction during fingerprint liveness detection. 展开更多
关键词 fingerprint liveness detection wavelet transform local phase quantity principal component analysis support vector machine
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Prediction Model of Data Envelopment Analysis with Undesirable Outputs 被引量:2
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作者 边馥萍 范宇 《Transactions of Tianjin University》 EI CAS 2004年第1期34-38,共5页
Data envelopment analysis (DEA) has become a standard non parametric approach to productivity analysis, especially to relative efficiency analysis of decision making units (DMUs). Extended to the prediction field, it ... Data envelopment analysis (DEA) has become a standard non parametric approach to productivity analysis, especially to relative efficiency analysis of decision making units (DMUs). Extended to the prediction field, it can solve the prediction problem with multiple inputs and outputs which can not be solved easily by the regression analysis method.But the traditional DEA models can not solve the problem with undesirable outputs,so in this paper the inherent relationship between goal programming and the DEA method based on the relationship between multiple goal programming and goal programming is explored,and a mixed DEA model which can make all factors of inputs and undesirable outputs decrease in different proportions is built.And at the same time,all the factors of desirable outputs increase in different proportions. 展开更多
关键词 data envelopment analysis(DEA) undesirable outputs multiple goal programming mixed DEA model PREDICTION
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A framework of region-based dynamic image fusion 被引量:1
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作者 WANG Zhong-hua QIN Zheng LIU Yu 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2007年第1期56-62,共7页
A new framework of region-based dynamic image fusion is proposed. First, the technique of target detection is applied to dynamic images (image sequences) to segment images into different targets and background regions... A new framework of region-based dynamic image fusion is proposed. First, the technique of target detection is applied to dynamic images (image sequences) to segment images into different targets and background regions. Then different fusion rules are employed in different regions so that the target information is preserved as much as possible. In addition, steerable non-separable wavelet frame transform is used in the process of multi-resolution analysis, so the system achieves favorable characters of orientation and invariant shift. Compared with other image fusion methods, experimental results showed that the proposed method has better capabilities of target recognition and preserves clear background information. 展开更多
关键词 Dynamic image fusion Region segmentation Non-separable wavelet frame
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Study on spillover effect of copper futures between LME and SHFE using wavelet multiresolution analysis 被引量:2
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作者 WANG Su-nan PAN Yun-he YANG Jian-gang 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2007年第8期1290-1295,共6页
Research on information spillover effects between financial markets remains active in the economic community. A Granger-type model has recently been used to investigate the spillover between London Metal Exchange(LME)... Research on information spillover effects between financial markets remains active in the economic community. A Granger-type model has recently been used to investigate the spillover between London Metal Exchange(LME) and Shanghai Futures Exchange(SHFE) ,however,possible correlation between the future price and return on different time scales have been ignored. In this paper,wavelet multiresolution decomposition is used to investigate the spillover effects of copper future returns between the two markets. The daily return time series are decomposed on 2n(n=1,…,6) frequency bands through wavelet mul-tiresolution analysis. The correlation between the two markets is studied with decomposed data. It is shown that high frequency detail components represent much more energy than low-frequency smooth components. The relation between copper future daily returns in LME and that in SHFE are different on different time scales. The fluctuations of the copper future daily returns in LME have large effect on that in SHFE in 32-day scale,but small effect in high frequency scales. It also has evidence that strong effects exist between LME and SHFE for monthly responses of the copper futures but not for daily responses. 展开更多
关键词 Spillover effect Copper future Future market Wavelet multiresolution analysis
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Lifting transform via Savitsky-Golay filter predictor and application of denoising 被引量:3
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作者 周广柱 杨锋杰 王翠珍 《Journal of Coal Science & Engineering(China)》 2006年第2期66-69,共4页
The Savitsky-Golay filter isa smoothing filter based on polynomial regression.Itemploys the regression fitting capacity to improve the smoothing results.But Savit-sky-Golay filter uses a fix sized window.It has the sa... The Savitsky-Golay filter isa smoothing filter based on polynomial regression.Itemploys the regression fitting capacity to improve the smoothing results.But Savit-sky-Golay filter uses a fix sized window.It has the same shortage of Window FourierTransform.Wavelet mutiresolution analysis may deal with this problem.In this paper,tak-ing advantage of Savitsky-Golay filter's fitting ability and the wavelet transform's multiscaleanalysis ability,we developed a new lifting transform via Savitsky-Golay smoothing filteras the lifting predictor,and then processed the signals comparing with the ordinary Savit-sky-Golay Smoothing method.We useed the new lifting in noisy heavy sine denoising.Thenew transform obviously has better denoise ability than ordinary Savitsky-Golay smooth-ing method.At the same time singular points are perfectly retained in the denoised signal.Singularity analysis,multiscale interpolation,estimation,chemical data smoothing andother potential signal processing utility of this new lifting transform are in prospect. 展开更多
关键词 lifting wavelet Savitsky-Golay filter PREDICTOR DENOISE
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Oncologic outcomes of primary and post-irradiated early stage rectal cancer: A retrospective cohort study 被引量:6
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作者 Chang—ZhengDu Yong—ChunChen +2 位作者 YongCai Wei—ChengXue. JinGU 《World Journal of Gastroenterology》 SCIE CAS CSCD 2011年第27期3229-3234,共6页
AIM: To evaluate the oncologic outcomes of primary and post-irradiated early stage rectal cancer and the effectiveness of adjuvant chemotherapy for rectal cancer patients. METHODS: Eighty-four patients with stage Ⅰ r... AIM: To evaluate the oncologic outcomes of primary and post-irradiated early stage rectal cancer and the effectiveness of adjuvant chemotherapy for rectal cancer patients. METHODS: Eighty-four patients with stage Ⅰ rectal cancer after radical surgery were studied retrospectively and divided into ypstage Ⅰ group (n = 45) and pstage Ⅰ group (n = 39), according to their preoperative radiation, and compared by univariate and multivariate analysis. RESULTS: The median follow-up time of patients was 70 mo. No significant difference was observed in diseaseprogression between the two groups. The 5-year disease-free survival rate was 84.4% and 92.3%, respectively (P = 0.327) and the 5-year overall survival rate was 88.9% and 92.3%, respectively, for the two groups (P = 0.692). The disease progression was not significantly associated with the pretreatment clinical stage in ypstage Ⅰ group. The 5-year disease progression rate was 10.5% and 19.2%, respectively, for the patients who received adjuvant chemotherapy and for those who rejected chemotherapy in the ypstage Ⅰ group (P = 0.681). CONCLUSION: The oncologic outcomes of primary and post-irradiated early stage rectal cancer are similar. Patients with ypstage Ⅰ rectal cancer may slightly benefit from adjuvant chemotherapy. 展开更多
关键词 Rectal cancer Neoadjuvant radiotherapy Total mesorectal excision
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Numerical Simulation for Accuracy of Velocity Analysis in Small-Scale High-Resolution Marine Multichannel Seismic Technology 被引量:5
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作者 LUO Di CAI Feng WU Zhiqiang 《Journal of Ocean University of China》 SCIE CAS CSCD 2017年第3期370-382,共13页
When used with large energy sparkers, marine multichannel small-scale high-resolution seismic detection technology has a high resolution, high-detection precision, a wide applicable range, and is very flexible. Positi... When used with large energy sparkers, marine multichannel small-scale high-resolution seismic detection technology has a high resolution, high-detection precision, a wide applicable range, and is very flexible. Positive results have been achieved in submarine geological research, particularly in the investigation of marine gas hydrates. However, the amount of traveltime difference information is reduced for the velocity analysis under conditions of a shorter spread length, thus leading to poorer focusing of the velocity spectrum energy group and a lower accuracy of the velocity analysis. It is thus currently debatable whether the velocity analysis accuracy of short-arrangement multichannel seismic detection technology is able to meet the requirements of practical application in natural gas hydrate exploration. Therefore, in this study the bottom boundary of gas hydrates(Bottom Simulating Reflector, BSR) is used to conduct numerical simulation to discuss the accuracy of the velocity analysis related to such technology. Results show that a higher dominant frequency and smaller sampling interval are not only able to improve the seismic resolution, but they also compensate for the defects of the short-arrangement, thereby improving the accuracy of the velocity analysis. In conclusion, the accuracy of the velocity analysis in this small-scale, high-resolution, multi-channel seismic detection technology meets the requirements of natural gas hydrate exploration. 展开更多
关键词 SMALL-SCALE HIGH-RESOLUTION multichannel seismic velocity analysis accuracy gas hydrate
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Multi-resolution graph-based clustering analysis for lithofacies identifi cation from well log data: Case study of intraplatform bank gas fi elds, Amu Darya Basin 被引量:13
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作者 Tian Yu Xu Hong +4 位作者 Zhang Xing-Yang Wang Hong-Jun Guo Tong-Cui Zhang Liang-Jie Gong Xing-Lin 《Applied Geophysics》 SCIE CSCD 2016年第4期598-607,736,共11页
In this study, we used the multi-resolution graph-based clustering (MRGC) method for determining the electrofacies (EF) and lithofacies (LF) from well log data obtained from the intraplatform bank gas fields loc... In this study, we used the multi-resolution graph-based clustering (MRGC) method for determining the electrofacies (EF) and lithofacies (LF) from well log data obtained from the intraplatform bank gas fields located in the Amu Darya Basin. The MRGC could automatically determine the optimal number of clusters without prior knowledge about the structure or cluster numbers of the analyzed data set and allowed the users to control the level of detail actually needed to define the EF. Based on the LF identification and successful EF calibration using core data, an MRGC EF partition model including five clusters and a quantitative LF interpretation chart were constructed. The EF clusters 1 to 5 were interpreted as lagoon, anhydrite flat, interbank, low-energy bank, and high-energy bank, and the coincidence rate in the cored interval could reach 85%. We concluded that the MRGC could be accurately applied to predict the LF in non-cored but logged wells. Therefore, continuous EF clusters were partitioned and corresponding LF were characteristics &different LF were analyzed interpreted, and the distribution and petrophysical in the framework of sequence stratigraphy. 展开更多
关键词 Multi-resolution graph-based clustering method electrofacies lithofacies intraplatform bank gas fields Amu Darya Basin
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The Construction of a Class of Compactly Supported Orthogonal Matrix-valued 被引量:1
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作者 CHEN Qing-jiang CHENG Chuan-rui CHENG Zheng-xing 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2006年第4期608-616,共9页
In this paper,we introduce matrix-valued multiresolution analysis and orthogonal matrix-valued wavelets.We obtain a necessary and sufficient condition on the existence of orthogonal matrix-valued wavelets by means of ... In this paper,we introduce matrix-valued multiresolution analysis and orthogonal matrix-valued wavelets.We obtain a necessary and sufficient condition on the existence of orthogonal matrix-valued wavelets by means of paraunitary vector filter bank theory.A method for constructing a class of compactly supported orthogonal matrix-valued wavelets is proposed by using multiresolution analysis method and matrix theory. 展开更多
关键词 ORTHOGONAL matrix-valued multiresolution analysis matrix-valued scal-ing fun-nctions matrix-valued wavelets Hermitian matrix
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Denoising Method for Shear Probe Signal Based on Wavelet Thresholding 被引量:2
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作者 王树新 肖学忠 +2 位作者 王延辉 王子龙 陈宝阔 《Transactions of Tianjin University》 EI CAS 2012年第2期135-140,共6页
Shear probe works under a tough environment where the turbulence signals to be measured are very weak. The measured turbulence signals often contain a large amount of noise. Due to wide frequency band, noise signals c... Shear probe works under a tough environment where the turbulence signals to be measured are very weak. The measured turbulence signals often contain a large amount of noise. Due to wide frequency band, noise signals cannot be effectively removed by traditional methods based on Fourier transform. In this paper, a wavelet thresholding denoising method is proposed for turbulence signal processing in that wavelet analysis can be used for multi-resolution analysis and can extract local characteristics of the signals in both time and frequency domains. Turbulence signal denoising process is modeled based on the wavelet theory and characteristics of the turbulence signal. The threshold and decomposition level, as well as the procedure of the turbulence signal denoising, are determined using the wavelet thresholding method. The proposed wavelet thresholding method was validated by turbulence signal denoising of the Western Pacific Ocean trial data. The results show that the propsed method can reduce the noise in the measured signals by shear probes, and the frequency spectrums of the denoised signal correspond well to the Nasmyth spectrum. 展开更多
关键词 wavelet analysis THRESHOLD shear probe signal processing
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Non-classical Algorithm for Time Series Prediction of the Range of Economic Phenomena With Regard to the Interaction of Financial Market Indicators 被引量:2
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作者 Monika Hadas-Dyduch 《Chinese Business Review》 2014年第4期221-231,共11页
The aim of the article is to present non-clasical copyrighted algorithm for prediction of time series, presenting macroeconomic indicators and stock market indices. The algorithm is based on artificial neural networks... The aim of the article is to present non-clasical copyrighted algorithm for prediction of time series, presenting macroeconomic indicators and stock market indices. The algorithm is based on artificial neural networks and multi-resolution analysis (the algorithm is based on Daubechies wavelet). However, the main feature of the algorithm, which gives a good quality of the forecasts, is all included in the series analysis division into, a few partial under-series and prediction dependence on a number of other economic series. The algorithm used for the prediction, is copyrighted algorithm, labeled M.H-D in this article. Application of the algorithm was performed on a series presenting WIG 20. The forecast of WIG 20 was conditional on trading the Dow Jones, DAX, Nikkei, Hang Seng, taking into account the sliding time window. As an example application of copyrighted model, the forecast of WIG 20 for a period of two years, one year, six month was appointed. An empirical example is described. It shows that the proposed model can predict index with the scale of two years, one year, a half year and other intervals. Precision of prediction is satisfactory. An average absolute percentage error of each forecast was: 0.0099%---for two-year forecasts WIG 20; 0.0552%--for the annual forecast WIG 20; and 0.1788%---for the six-month forecasts WIG 20. 展开更多
关键词 macroeconomic indicators stock index forecasting WAVELET neural network wavelet transform Daubechies wavelet
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Investigation of nanometer-scale films using low angle Xray reflectivity analysis in IPOE 被引量:1
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作者 WANG Zhan-shan XU Yao WANG Hong-chang ZHU Jing-tao ZHANG Zhong WANG Feng-li CHEN Ling-yan 《Optoelectronics Letters》 EI 2007年第2期88-90,共3页
The X-ray low angle reflectivity measurement is used to investigate single and bilayer films to determine the parameters of nanometer-scale structures,three effectual methods are presented by using X-ray reflectivity ... The X-ray low angle reflectivity measurement is used to investigate single and bilayer films to determine the parameters of nanometer-scale structures,three effectual methods are presented by using X-ray reflectivity analysis to provide an accurate estimation of the nanometer film structures. The parameters of tungsten (W) single layer, such as the material density, interface roughness and deposition rate, were obtained easily and speedily. The base metal layer was introduced to measure the profiles of single low Z material film. A 0.3 nm chromium (Cr) film was also studied by low angle reflectivity analysis. 展开更多
关键词 IPOE 纳米级薄膜 X线反射分析 多层结构 参数
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A clinical analysis and prognostic study of 62 cases with T1G3 urothelial carcinoma of the bladder
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作者 Fengyao Wang Qinchao Yu Yanan Liu 《The Chinese-German Journal of Clinical Oncology》 CAS 2012年第4期233-236,共4页
Objective:The aim of our study was to clarify the clinicopathological factors affecting the outcome of T1G3 urothelial carcinoma of the bladder.Methods:We retrospectively reviewed 62 cases of T1G3 bladder cancer treat... Objective:The aim of our study was to clarify the clinicopathological factors affecting the outcome of T1G3 urothelial carcinoma of the bladder.Methods:We retrospectively reviewed 62 cases of T1G3 bladder cancer treated with transuretheral resection of bladder toumor (TURBT) followed by intravesical instillation between 1997 and 2009.Cumulative survival was analyzed by Kaplan-Meier method.Cox regression was used for univariate and multivariate analysis.Log-rank method was used for the significance test.The statistical difference was accepted when the P value was lower than 0.05.Results:Median follow-up period was 40 months (6-140 months).Forty-one cases of intravesical recurrence (66%) were observed during follow-up.Two-and 5-year recurrence-free survival rates were 43.4% and 35.1%.Fourteen cases of progression (23%) were observed during the follow-up period.Two-and 5-year progression-free survival rates were 86.4% and 83.5%,respectively.Significant factors for tumor recurrence and progression were analyzed by Cox regression.Tumor multiplicity (RR=2.250),size (RR=1.039) and history of recurrence (RR=2.162) were significantly correlated with recurrence and tumor multiplicity (RR=3.695) was significantly correlated with progression on multivariate analysis.Conclusion:Tumor multiplicity,size,history of recurrence were correlated with recurrence and tumor multiplicity was significantly correlated with progression.Tumor multiplicity,size and history of recurrence should be taken into account when we make therapy strategies for T1G3 urothelial carcinoma of the bladder. 展开更多
关键词 T1G3 urothelial carcinoma of the bladder PROGNOSIS survival analysis
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Clinical analysis of long-term survivors for unresectable hepatocellular carcinoma
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作者 Baihong Zhang Xianghui Wang +1 位作者 Hongyun Yue Changquan Ling 《The Chinese-German Journal of Clinical Oncology》 CAS 2010年第3期161-164,共4页
Objective:The objectives of this study were to evaluate the long-term results with multimodality therapy, and to clarify the clinicopathologic of features of patients surviving ≥ 3 years for unresectable hepatocellul... Objective:The objectives of this study were to evaluate the long-term results with multimodality therapy, and to clarify the clinicopathologic of features of patients surviving ≥ 3 years for unresectable hepatocellular carcinoma(HCC).Methods:Between 1999 and 2003, a total of 166 patients underwent multimodality therapy for unresectable HCC.All patients underwent multimodality therapy, such as transarterial chemoembolization(TACE), chemotherapy, local ablative therapy, and/ or Chinese traditional medicine.Thirty-nine(23.5%) patients survival ≥ 1 years, and 10(6.0%) patients survived ≥ 3 years.These 39 patients surviving over 1 year were investigated in this study.Eighteen clinical and biologic variables were assessed using univariate and multivariate analyses.Results:TNM staging and tumor extension were isolated by univariate analysis.Only tumor extension was independent risk factors by multiple regression analysis.Of these, 25.6%(10 of 39) survived over 3 years.These 10 patients surviving over 3 years were investigated further.By the end of June 2004, follow-up varied from 3 years and 2 months to 5 years and 1 month.Six patients were still alive with free of disease.Conclusion:Tumor extension was demonstrated to be prognostic of long-term survivors.Multimodality therapy may make a major contribution to achieving long-term survival in patients with unresectable HCC. 展开更多
关键词 hepatocellular carcinoma SURVIVAL prognostic features multimodality therapy
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Prediction of cavity growth rate during underground coal gasification using multiple regression analysis 被引量:8
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作者 Mehdi Najafi Seyed Mohammad Esmaiel Jalali +1 位作者 Reza KhaloKakaie Farrokh Forouhandeh 《International Journal of Coal Science & Technology》 EI 2015年第4期318-324,共7页
During underground coal gasification (UCG), whereby coal is converted to syngas in situ, a cavity is formed in the coal seam. The cavity growth rate (CGR) or the moving rate of the gasification face is affected by... During underground coal gasification (UCG), whereby coal is converted to syngas in situ, a cavity is formed in the coal seam. The cavity growth rate (CGR) or the moving rate of the gasification face is affected by controllable (operation pressure, gasification time, geometry of UCG panel) and uncontrollable (coal seam properties) factors. The CGR is usually predicted by mathematical models and laboratory experiments, which are time consuming, cumbersome and expensive. In this paper, a new simple model for CGR is developed using non-linear regression analysis, based on data from 1 l UCG field trials. The empirical model compares satisfactorily with Perkins model and can reliably predict CGR. 展开更多
关键词 Underground coal gasification (UCG) - Cavity growth rate . Multiple regression analysis ~ Empirical model
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The Study on Scaling Function of L^2(R^s)
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作者 HUANG Yong-dong LI Hua WU Guo-chang 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2007年第4期567-573,共7页
In this paper, using the orthonormal multiresolution analysis(MRA) of L^2(R^s), we get two important properties of the scaling function with dilation matrix A = MI of L^2 (R^s). These properties axe chaxacterize... In this paper, using the orthonormal multiresolution analysis(MRA) of L^2(R^s), we get two important properties of the scaling function with dilation matrix A = MI of L^2 (R^s). These properties axe chaxacterized by some inequalities and equalities. 展开更多
关键词 multiresolution analysis compact support scaling function Fouries transform.
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Weekend and nighttime effect on the prognosis of peptic ulcer bleeding 被引量:6
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作者 Young Hoon Youn Yong Jin Park +3 位作者 Jae Hak Kim Tae Joo Jeon Jae Hee Cho Hyojin Park 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第27期3578-3584,共7页
AIM:To evaluate whether weekend or nighttime admission affects prognosis of peptic ulcer bleeding despite early endoscopy.METHODS:Retrospective data collection from four referral centers,all of which had a formal out-... AIM:To evaluate whether weekend or nighttime admission affects prognosis of peptic ulcer bleeding despite early endoscopy.METHODS:Retrospective data collection from four referral centers,all of which had a formal out-of-hours emergency endoscopy service,even at weekends.A total of 388 patients with bleeding peptic ulcers who were admitted via the emergency room between January 2007 and December 2009 were enrolled.Analyzed parameters included time from patients' arrival until endoscopy,mortality,rebleeding,need for surgery and length of hospital stay.RESULTS:The weekday and weekend admission groups comprised 326 and 62 patients,respectively.There were no significant differences in baseline characteristics between the two groups,except for younger age in the weekend group.Most patients (97%) had undergone early endoscopy,which resulted in a low mortality rate regardless of point of presentation (1.8% overall vs 1.6% on the weekend).The only outcome that was worse in the weekend group was a higher rate of rebleeding (12% vs 21%,P = 0.030).However,multivariate analysis revealed nighttime admission and a high Rockall score (≥ 6) as significant independent risk factors for rebleeding,rather than weekend admission.CONCLUSION:Early endoscopy for peptic ulcer bleeding can prevent the weekend effect,and nighttime admission was identified as a novel risk factor for rebleeding,namely the nighttime effect. 展开更多
关键词 Early endoscopy Nighttime effect Pepticulcer bleeding REBLEEDING Weekend effect
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Analysis on electric energy measuring method based on multi-resolution analysis
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作者 张晓冰 崔家瑞 +1 位作者 梁原华 王慕坤 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2006年第2期193-195,共3页
Along with the massive applications of the non-linear loads and the impact loads, many non-stationary stochastic signals such as harmonics, inter-harmonics, impulse signals and so on are introduced into the electric n... Along with the massive applications of the non-linear loads and the impact loads, many non-stationary stochastic signals such as harmonics, inter-harmonics, impulse signals and so on are introduced into the electric network, and these non-stationary stochastic signals have had effects on the accuracy of the measurement of electric energy. The traditional method like Fourier Analysis can he applied efficiently on the stationary stochastic signals, hut it has little effect on non-stationary stochastic signals. In light of this, the form of the signals of the electric network in wavelet domain will he discussed in this paper. A measurement method of active power based on multi-resolution analysis in the stochastic process is presented. This method has a wider application scope compared with the traditional method Fourier analysis, and it is of good referential value and practical value in terms of raising the level of the existing electric energy measurement. 展开更多
关键词 electric energy measurement multi-resolution analysis active power
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