期刊文献+
共找到69篇文章
< 1 2 4 >
每页显示 20 50 100
碱灰化法测定微量尿碘的质量控制
1
作者 薛淑莲 赵淑芳 +1 位作者 曲成毅 葛晓静 《山西医科大学学报》 CAS 1997年第1期37-38,共2页
在微量尿碘分析中,因碱灰化法具较多优点而广泛应用。为了更好掌握其测定方法的精密度和准确度,本文介绍了简便易行的碱灰化法实验室内质量控制方法。
关键词 尿液检验 类化法 尿碘 质量控制
下载PDF
Driving fatigue fusion detection based on T-S fuzzy neural network evolved by subtractive clustering and particle swarm optimization 被引量:6
2
作者 孙伟 张为公 +1 位作者 李旭 陈刚 《Journal of Southeast University(English Edition)》 EI CAS 2009年第3期356-361,共6页
In order to improve the accuracy and reliability of the driving fatigue detection based on a single feature, a new detection algorithm based on multiple features is proposed. Two direct driver's facial features refle... In order to improve the accuracy and reliability of the driving fatigue detection based on a single feature, a new detection algorithm based on multiple features is proposed. Two direct driver's facial features reflecting fatigue and one indirect vehicle behavior feature indicating fatigue are considered. Meanwhile, T-S fuzzy neural network(TSFNN)is adopted to recognize the driving fatigue of drivers. For the structure identification of the TSFNN, subtractive clustering(SC) is used to confirm the fuzzy rules and their correlative parameters. Moreover, the particle swarm optimization (PSO)algorithm is improved to train the TSFNN. Simulation results and experiments on vehicles show that the proposed algorithm can effectively improve the convergence speed and the recognition accuracy of the TSFNN, as well as enhance the correct rate of driving fatigue detection. 展开更多
关键词 driving fatigue fusion detection particle swarm optimization(PSO) subtractive clustering(SC)
下载PDF
STRUCTURE OPTIMIZATION STRATEGY OF NORMALIZED RBF NETWORKS 被引量:1
3
作者 祖家奎 赵淳生 戴冠中 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2003年第1期73-78,共6页
Aimed at studying normali zed radial basis function network (NRBFN), this paper introduces the subtractiv e clustering based on a mountain function to construct the initial structure of NR BFN, adopts singular value ... Aimed at studying normali zed radial basis function network (NRBFN), this paper introduces the subtractiv e clustering based on a mountain function to construct the initial structure of NR BFN, adopts singular value decomposition (SVD) to analyze the relationship betwe en neural nodes of the hidden layer and singular values, cumulative contribution ratio, index vector, and optimizes the structure of NRBFN. Finally, simulation and performance comparison show that the algorithm is feasible and effective. 展开更多
关键词 radial basis function n etworks subtractive clustering singular value decomposition structure optimiz ation
下载PDF
Determination of Total Flavones Content in Ceratocarpus arenarius L. by Spectrophotometry
4
作者 刘珊珊 马先梅 杨红兵 《Agricultural Science & Technology》 CAS 2011年第11期1612-1614,共3页
[Objective] The aim was to establish the method for determining total flavoens content in Ceratocarpus arenarius L.[Method ] Flavonoids were extracted from C. arenarius by heating refluxing, and determined with rutin ... [Objective] The aim was to establish the method for determining total flavoens content in Ceratocarpus arenarius L.[Method ] Flavonoids were extracted from C. arenarius by heating refluxing, and determined with rutin as the standard.[Result] In the range of 0.019-0.102 mg/ml, linear relationship was good (r=0.999 1). This method had higher precision and accuracy with RSD of 0.226% and recoveries of 99.36%. The total flavones content from C. arenarius was 10.12 mg/g. [Conclusion] The method is simple and reliable, which could be used to control the quality of C. arenariu. 展开更多
关键词 Ceratocarpus arenarius L. FLAVONOIDS SPECTROPHOTOMETRY
下载PDF
Antioxidant phenanthrenes and lignans from Dendrobium nobile 被引量:6
5
作者 张雪 续洁琨 +2 位作者 王乃利 栗原博 姚新生 《Journal of Chinese Pharmaceutical Sciences》 CAS 2008年第4期314-318,共5页
To study the antioxidant constituents from the stems of Dendrobium nobile, and to discuss theft structure-activity relationship. Compounds were isolated from a 60% ethanolic extract by various chromatographic techniqu... To study the antioxidant constituents from the stems of Dendrobium nobile, and to discuss theft structure-activity relationship. Compounds were isolated from a 60% ethanolic extract by various chromatographic techniques and were identified by spectral analysis. The antioxidant activities of compounds were evaluated by DPPH free radical scavenging assay. Five phenanthrenes and four lignans were obtained from the active fractions ofD. nobile. Their structures were identified as fimbriatone (1), confusarin (2), flavanthrinin (3), 2,5-dihydroxy-4,9-dimethoxyphenanthrene (4), 3,7-dihydroxy-2,4-dimethoxyphenanthrene (5), syringaresinol (6), pinoresinol (7), medioresinol (8) and lirioresinol-A (9), respectively. Compounds 2 and 6 exhibited more potent DPPH scavenging activities than vitamin C. All the above compounds were reported from this plant for the first time, and compounds 3, 4 and 9 were reported for the first time from the genus of Dendrobiurn. For all phenanthrenes and lignans, an electron-donating methoxyl group in the ortho position to the phenolic hydroxyl group exhibits enhanced antioxidant activities. 展开更多
关键词 Dendrobium nobile PHENANTHRENES Lignans Antioxidant activity DPPH free radical scavenging assay Structureactivity relationship
下载PDF
汉语语音与成语
6
作者 师为公 《苏州科技学院学报(社会科学版)》 1994年第2期50-52,62,共4页
汉语的重要特点之一是音义结合关系上一与多的对应,它不仅造成了单音节层次上大量同音词及语素,同时还有相当数量的复音节同音词及少量的同音成语.其中少量同音或音近的复音词、成语是由于语词使用中音义的讹变而成的,二者有母子关系.... 汉语的重要特点之一是音义结合关系上一与多的对应,它不仅造成了单音节层次上大量同音词及语素,同时还有相当数量的复音节同音词及少量的同音成语.其中少量同音或音近的复音词、成语是由于语词使用中音义的讹变而成的,二者有母子关系.这种情形除涉及汉语语音特点外,还与语音史词汇史密切相关,有时空性.有人拘泥于字典或文献,只承认母词的合法性,视子词为不规范的语病而时时予以痛诋,但也有人认为语言是一个开放体系,有社会性的特点及特殊的新陈代谢规律,不能一概排斥异己.实际上,这种词语的变迁不同于一般的写错别字,它们多是不违反汉语语、修、逻规律而重新组装的新词.例如,现代汉语有“验收”一词,但人们对验收过程中的吃喝风颇为反感,代之以“宴收”,则是一种可以理喻的新概括了.苏州人将横塘写作“枉塘”, 展开更多
关键词 汉语语音 单音节 讹变 现代汉语 元曲选 排斥异己 类化法 母子关系 时空性 内部形式
下载PDF
形声字的特点、局限及功用
7
作者 田雨泽 《十堰职业技术学院学报》 1989年第2期27-31,共5页
(一) 形声字构字方法简单,只需将义符和声符并合在一起就成一字。它不象象形、指事、会意字那样,要顾及到形体的相似、意思的相合与否。因此,凡是那些无形可象、无事可指、无意可会的字,都可以用形声造字法比较容易地造出来。这种造字... (一) 形声字构字方法简单,只需将义符和声符并合在一起就成一字。它不象象形、指事、会意字那样,要顾及到形体的相似、意思的相合与否。因此,凡是那些无形可象、无事可指、无意可会的字,都可以用形声造字法比较容易地造出来。这种造字方法的出现,极大地改变了人们的造字观念,打开了眼界,不再囿于象形、象意的束缚,培养了更高的概括能力。 展开更多
关键词 造字 义符 表义 概括能力 可象 古今字 类化法 文字发展 上古韵部 《康熙字典》
下载PDF
Isolation of Plasma and Thylakoid Membranes from the Heterocystous Cyanobacterium Anabaena sp. PCC 7120
8
作者 李斌 徐冬一 赵进东 《Acta Botanica Sinica》 CSCD 2001年第6期650-652,共3页
利用水溶性多聚体双相法分离蓝细菌Anabaenasp .PCC 712 0质膜和类囊体膜两种膜系统。吸收光谱分析表明 ,质膜相和类囊体膜相的主要色素分别为类胡萝卜素和叶绿素。SDS_凝胶电泳显示这两种膜系统蛋白组成有很大差别。这种分离方法容易操... 利用水溶性多聚体双相法分离蓝细菌Anabaenasp .PCC 712 0质膜和类囊体膜两种膜系统。吸收光谱分析表明 ,质膜相和类囊体膜相的主要色素分别为类胡萝卜素和叶绿素。SDS_凝胶电泳显示这两种膜系统蛋白组成有很大差别。这种分离方法容易操作 ,对研究蓝细菌的膜蛋白和膜脂非常有用。 展开更多
关键词 CYANOBACTERIUM plasma and thylakoid membranes isolation and purification two_phase partition
下载PDF
The Syntheses of β-Carboline-3-carboxamides Derivatives and TheirInteraction with DNA
9
作者 林伟 肖苏龙 杨铭 《Journal of Chinese Pharmaceutical Sciences》 CAS 2001年第3期119-123,共5页
To study the interactions of these compounds with calf thymus DNA(CT-DNA), seven b-carboline-3-carboxamides were designed and synthesized. The interactions of these compounds with CT-DNA were determined by the viscome... To study the interactions of these compounds with calf thymus DNA(CT-DNA), seven b-carboline-3-carboxamides were designed and synthesized. The interactions of these compounds with CT-DNA were determined by the viscometric titration assay and Tm (melting temperature) value assay. Binding strengths were evaluated by spectrophotometric titration experiment and microcalorimetric measurement. The interactions of these compounds were tested with CT-DNA. It was showed that all of these compounds were able to change the Tm value of CT-DNA. The results of viscometric titration assay indicated that these compounds interacted with CT-DNA by intercalation. Spectrophotometric titration experiment showed that the binding strengths of these compounds with CT-DNA were different, which was well in agreement with the cell culture results. The binding was driven by entropy according to the results of the microcalorimetric measurement. This series of b-carboline-3-carboxamides is DNA targeting compounds. Their obvious antitumor biological effect is based on the intercalation with DNA base-pairs. 展开更多
关键词 b-Carboline-3-carboxamides Chemical synthesis CT-DNA
下载PDF
Carbon quantum dot preparation and application to detecting active ingredients in traditional Chinese medicine 被引量:4
10
作者 Bo Liu Shangxin Guo +1 位作者 Xiaohui Fan Xingchu Gong 《Acupuncture and Herbal Medicine》 2021年第2期81-89,共9页
Carbon quantum dots(CQDs)are fluorescent carbon nanomaterials that have been applied to biology,medicine,and optoelectronics,owing to their significant advantages such as simple synthesis methods,low cost,and widely a... Carbon quantum dots(CQDs)are fluorescent carbon nanomaterials that have been applied to biology,medicine,and optoelectronics,owing to their significant advantages such as simple synthesis methods,low cost,and widely available sources of raw synthesis materials.This review summarizes CQD preparation methods,which include hydrothermal and microwave-assisted synthesis methods,as well as separation methods such as centrifugation,dialysis,and filtration.Additionally,we review the application of CQDs in the detection of active ingredients,primarily phenolic compounds,in traditional Chinese medicine.We also discuss the quenching mechanism of CQD fluorescence using the active ingredients of traditional Chinese medicine.Limitations such as insufficient test selectivity,weak fluorescence intensity,and an unclear quantitative relationship between preparation methods and properties should be resolved for the efficient use of CQDs to detect active ingredients in Chinese medicine. 展开更多
关键词 Carbon quantum dots FLAVONOIDS Fluorescence quenching Phenolic compounds Quality control Traditional Chinese medicine
下载PDF
Late SV40 factor:A key mediator of Notch signaling in human hepatocarcinogenesis 被引量:15
11
作者 Ren-Hua Fan Jing Li Nan Wu Ping-Sheng Chen 《World Journal of Gastroenterology》 SCIE CAS CSCD 2011年第29期3420-3430,共11页
AIM:To investigate the relationship between late SV40 factor(LSF)and Notch signaling in the development and progress of hepatocellular carcinoma(HCC).METHODS:Liver cancer tissue specimens from 25 patients were analyze... AIM:To investigate the relationship between late SV40 factor(LSF)and Notch signaling in the development and progress of hepatocellular carcinoma(HCC).METHODS:Liver cancer tissue specimens from 25 patients were analyzed for Notch-1 and LSF expression by immunohistochemistry.The correlation between expression and the biological effects of Notch-1 and LSF were analyzed using genetic and pharmacological strategies in HCC cell lines and human normal cell lines,including hepatic stellate cells(HSC)and human embryonic kidney epithelial cells(HEK).RESULTS:Immunohistochemistry showed that both Notch-1 and LSF were significantly upregulated in HCC samples(76%,19/25,P<0.0001 and 84%,21/25,P<0.0001,respectively)compared with non-cancer samples.Activation of Notch-1 by exogenous transfection of Notch1 intracellular domain increased LSF expression in HSC and HEK cells to levels similar to those seen in HepG2 cells.Furthermore,blocking Notch-1 activation with aγ-secretase inhibitor,DAPT,downregulated LSF expression in HepG2 cells.Additionally,a biological behavior assay showed that forced overexpression of LSF promoted HepG2 cell proliferation and invasion.CONCLUSION:LSF is a key mediator of the Notch signaling pathway,suggesting that it might be a novel therapeutic target for the treatment of HCC. 展开更多
关键词 Notch receptor Late SV40 factor Signal transduction Hepatocellular carcinoma
下载PDF
Assessing the Eutrophication of Shengzhong Reservoir Based on Grey Clustering Method 被引量:4
12
作者 Pan An Hu Lihui +1 位作者 Li Tiesong Li Chengzhu 《Chinese Journal of Population,Resources and Environment》 2009年第2期83-87,共5页
Reservoir water environment is a grey system. The grey clustering method is applied to assessing the reservoir water enviromnent to establish a relatively complete model suitable for the reservoir eutrophication evalu... Reservoir water environment is a grey system. The grey clustering method is applied to assessing the reservoir water enviromnent to establish a relatively complete model suitable for the reservoir eutrophication evaluation and appropriately evaluate the quality of reservoir water, providing evidence for reservoir management. According to China's lakes and reservoir eutrophication criteria and the characteristics of China's eutrophication, as well as certain evaluation indices, the degree of eutrophication is classified into six categories with the utilization of grey classified whitening weight function to represent the boundaries of classification, to determine the clustering weight and clustering coefficient of each index in grey classifications, and the classification of each clustering object. The comprehensive evaluation of reservoir eutrophication is established on such a foundation, with Sichuan Shengzhong Reservoir as the survey object and the analysis of the data attained by several typical monitoring points there in 2006. It is found that eutrophication of Tiebian Power Generation Station, Guoyuanchang and Dashiqiao Bridge is the heaviest, Tielusi and Qinggangya the second, and Lijiaba the least. The eutrophication of this reservoir is closely relevant to the irrational exploitation in its surrounding areas, especially to the aggravation of the non-point source pollution and the increase of net-culture fishing. Therefore, it is feasible to use grey clustering in environment quality evaluation, and the point lies in the correct division of grey whitening function 展开更多
关键词 reservoir eutrophication grey clustering clustering weight clustering coefficient
下载PDF
A Method of Soil Salinization Information Extraction with SVM Classification Based on ICA and Texture Features 被引量:3
13
作者 ZHANG Fei TASHPOLAT Tiyip +5 位作者 KUNG Hsiang-te DING Jian-li MAMAT.Sawut VERNER Johnson HAN Gui-hong GUI Dong-wei 《Agricultural Science & Technology》 CAS 2011年第7期1046-1049,1074,共5页
Salt-affected soils classification using remotely sensed images is one of the most common applications in remote sensing,and many algorithms have been developed and applied for this purpose in the literature.This stud... Salt-affected soils classification using remotely sensed images is one of the most common applications in remote sensing,and many algorithms have been developed and applied for this purpose in the literature.This study takes the Delta Oasis of Weigan and Kuqa Rivers as a study area and discusses the prediction of soil salinization from ETM +Landsat data.It reports the Support Vector Machine(SVM) classification method based on Independent Component Analysis(ICA) and Texture features.Meanwhile,the letter introduces the fundamental theory of SVM algorithm and ICA,and then incorporates ICA and texture features.The classification result is compared with ICA-SVM classification,single data source SVM classification,maximum likelihood classification(MLC) and neural network classification qualitatively and quantitatively.The result shows that this method can effectively solve the problem of low accuracy and fracture classification result in single data source classification.It has high spread ability toward higher array input.The overall accuracy is 98.64%,which increases by10.2% compared with maximum likelihood classification,even increases by 12.94% compared with neural net classification,and thus acquires good effectiveness.Therefore,the classification method based on SVM and incorporating the ICA and texture features can be adapted to RS image classification and monitoring of soil salinization. 展开更多
关键词 Independent component analysis(ICA) Texture features Support vector machine(SVM) Soil salinizaiton
下载PDF
A New Fuzzy Clustering-Ranking Algorithm and Its Application in Process Alarm Management 被引量:6
14
作者 ZHU Qunxiong(朱群雄) +1 位作者 GENG Zhiqiang(耿志强) 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2005年第4期477-483,共7页
Overmany alarms of modern chemical process give the operators many difficulties to decision and diag- nosis. In order to ensure safe production and process operating, management and optimization of alarm information a... Overmany alarms of modern chemical process give the operators many difficulties to decision and diag- nosis. In order to ensure safe production and process operating, management and optimization of alarm information are challenge work that must be confronted. A new process alarm management method based on fuzzy clustering- ranking algorithm is proposed. The fuzzy clustering algorithm is used to cluster rationally the process variables, and difference driving decision algorithm ranks different clusters and process parameters in every cluster. The alarm signal of higher rank is handled preferentially to manage effectively alarms and avoid blind operation. The validity of proposed algorithm and solution is verified by the practical application of ethylene cracking furnace system. It is an effective and dependable alarm management method to improve operating safety in industrial process. 展开更多
关键词 process alarm management fuzzy clustering-ranking algorithm ethylene cracking furnace
下载PDF
Thoughts About Paths for Digitization of Traditional Chinese Medicine-Refined Data Elements 被引量:2
15
作者 ZHOU Xiao-Qing ZHANG Qi-Jie +2 位作者 ZHENG Cai-Xing TONG Tian-Hao YU Hao 《Digital Chinese Medicine》 2019年第1期1-6,共6页
For digitalization of traditional Chinese medicine(TCM),research is being conducted on objectivization of diagnosis and treatment,mathematical models of TCM theories,and application of modern information technology to... For digitalization of traditional Chinese medicine(TCM),research is being conducted on objectivization of diagnosis and treatment,mathematical models of TCM theories,and application of modern information technology to digitize the vast amounts of existing information.However,the author believes that TCM practitioners should first conduct a systematic and comprehensive refined analysis on the knowledge of TCM and unify data elements used in computer intelligence to avoid ambiguity.Thus,we must overcome the epistemological constraints and carefully analyze the relationship among data elements to achieve systematic results and administer TCM appropriately. 展开更多
关键词 Digital Chinese medicine Data element Refined classification TAXONOMY EPISTEMOLOGY
下载PDF
Flavonoids in Georgian Bee Bread and Bee Pollen 被引量:3
16
作者 Dodo Tavdidishvili Tsira Khutsidze +2 位作者 Manana Pkhakadze Maia Vanidze Aleko Kalandia 《Journal of Chemistry and Chemical Engineering》 2014年第7期676-681,共6页
The proposed work aims to study phenol components (flavonoids) of bee bread and pollen obtained in Georgia using the HPLC (high-performance liquid chromatography) method, and to determine the content of biological... The proposed work aims to study phenol components (flavonoids) of bee bread and pollen obtained in Georgia using the HPLC (high-performance liquid chromatography) method, and to determine the content of biologically active compounds in them. The samples were taken in lmereti region (west Georgia). After extraction of samples, there were carried out spectral and HPLC analysis of compounds for the sake of qualitative and quantitative research of them. There are studied the flavonoid compounds of bee bread and pollen by using the HPLC methods, and naringin, rutin and quercetin are identified. Their amount counts about 20% of full content of flavonoids. The content of flavonols in bee bread and pollen has been established. It also has been determined that the amount of flavonoids during the storage period of products reduces to 6.17-5.03 g.kg-1. 展开更多
关键词 Bee bread bee pollen PHENOLS FLAVONOIDS HPLC.
下载PDF
Synthesis and characterization of mibolerone 被引量:1
17
作者 杨青 范柏林 唐瑞仁 《Journal of Central South University of Technology》 EI 2007年第4期524-527,共4页
A simple and effective route for the synthesis of mibolerone was described starting from the estr-5(10)-en-3,17-dione in four steps with the overall yield of 47.0 %.Thus,two methods for key intermediate methylnorandro... A simple and effective route for the synthesis of mibolerone was described starting from the estr-5(10)-en-3,17-dione in four steps with the overall yield of 47.0 %.Thus,two methods for key intermediate methylnorandrost were investigated:one(method A)starting from estr-4-en-3,17-dione underwent 3-keto group protected with ethyl orthoformate to give 3-ethoxy-3,5-dien-estr-17-one,the other(method B)from estr-5(10)-en-3,17-dione and protected 3-keto group to give 3,3-dimethoxy-estr-5(10)-7-one in a mild acidic condition.Then,two intermediates were subsequently reacted with methyllithium followed by a mild hydrolytic procedure and gave methylnorandrost with total yield 25.0% and 86.0 %,respectively.In the preparation of 6-dehydrogenation product of methylnorandrost,two procedures(method C and method D)were investigated:one was the protected 17α-methyl-17β-hydroxy 3,5-enol ethers estrendiene brominated and the resulting 6-bromo-19-methylnortestosterone was then immediately dehydrohaloenated to give 6-dehydro-19-methylnortestosterone,the total yield only reaches 36.0%;the other was directly dehydrogenated with chloranil and the yield reaches 75.6% under the optimum conditions:in refluxing tetrahydrofuran,the molar ratio of methylnorandrost to chloranil is 0.66 and reaction time of 5 h.The titled compound and intermediates were characterized by 1H and 13C NMR,IRMS and elemental analysis. 展开更多
关键词 mibolerone methylnorandrost STEROIDS SYNTHESIS hepatic androgen receptor
下载PDF
Matrix metalloproteinase-2 as a superior biomarker for peritoneal deterioration in peritoneal dialysis 被引量:4
18
作者 Ichiro Hirahara Eiji Kusano +5 位作者 Yoshiyuki Morishita Makoto Inoue Tetsu Akimoto Osamu Saito Shigeaki Muto Daisuke Nagata 《World Journal of Nephrology》 2016年第2期204-212,共9页
AIM: To investigate the effcacy of effuent biomarkers for peritoneal deterioration with functional decline in peritoneal dialysis (PD).METHODS: From January 2005 to March 2013, the subjects included 218 PD patient... AIM: To investigate the effcacy of effuent biomarkers for peritoneal deterioration with functional decline in peritoneal dialysis (PD).METHODS: From January 2005 to March 2013, the subjects included 218 PD patients with end-stage renal disease at 18 centers. Matrix metalloproteinase-2 (MMP-2), interleukin-6 (IL-6), hyaluronan, and cancer antigen 125 (CA125) in peritoneal effluent were quantified with enzyme-linked immunosorbent assay. Peritoneal solute transport rate was assessed by peritoneal equilibration test (PET) to estimate peritoneal deterioration.RESULTS: The ratio of the effuent level of creatinine (Cr) obtained 4 h after injection (D) to that of plasma was correlated with the effluent levels of MMP-2 (ρ = 0.74, P 〈 0.001), IL-6 (ρ = 0.46, P 〈 0.001), and hyaluronan (ρ = 0.27, P 〈 0.001), but not CA125 (ρ = 0.13, P = 0.051). The area under receiver operating characteristic curve for the effluent levels of MMP-2, IL-6, and hyaluronan against high PET category were 0.90, 0.78, 0.62, and 0.51, respectively. No patient developed new-onset encapsulating peritoneal sclerosis for at least 1.5 years after peritoneal effuent sampling.CONCLUSION: The effuent MMP-2 level most closely reflected peritoneal solute transport rate. MMP-2 can be a reliable indicator of peritoneal deterioration with functional decline. 展开更多
关键词 Encapsulating peritoneal sclerosis MATRIX
下载PDF
Application of different clustering approaches to hydroclimatological catchment regionalization in mountainous regions, a case study in Utah State 被引量:1
19
作者 Elnaz SHARGHI Vahid NOURANI +1 位作者 Saeed SOLEIMANI Fahreddin SADIKOGLU 《Journal of Mountain Science》 SCIE CSCD 2018年第3期461-484,共24页
With respect to the different hydrological responses of catchments, even the adjacent ones, in mountainous regions, there are a great number of motivations for classifying them into homogeneous clusters. These motivat... With respect to the different hydrological responses of catchments, even the adjacent ones, in mountainous regions, there are a great number of motivations for classifying them into homogeneous clusters. These motivations include prediction in ungauged basins(PUB), model parameterization, understanding the potential impact of environmental changes, transferring information from gauged catchments to the ungauged ones. The present study investigated the similarity of catchments through the hydro-climatological pure time-series of a 14-year period from 2001 to 2015. Data sets encompass more than 13,000 month-station streamflow, rainfall, and temperature data obtained from 27 catchments in Utah State as one of the eight mountainous states of the USA. The identification, analysis, and interpretation of homogeneous catchments were investigated by applying the four approaches ofclustering, K-means, Ward, and SOM(Self-Organized Map) and a newly proposed Wavelet-Entropy-based(WE-SOM) clustering method. By using two clustering evaluation criteria, 3, 5, and 6 clusters were determined as the best numbers of clusters, depending on the method employed, where each cluster represents different hydro-climatological behaviors. Despite the absence of geographic characteristics in input data matrix, the results indicated a regionalization in agreement with topographic characteristics. Considering the dependency of the hydrological behavior of catchments on the physiographic field aspects and characteristics, WE-SOM method demonstrated a more acceptable performance, compared to the other three conventional clustering methods, by providing more clusters. WE-SOM appears to be a promising approach in catchment clustering. It preserves the topological structure of data which can, as a result, be proofed in a greater number of clusters by dividing data into higher numbers of distinct clusters withsimilar altitudes of catchments in each cluster. The results showed the aptitude of wavelets to quantify the time-based variability of temperature, rainfall and streamflow, in the way contributing to the regionalization of diverse catchments. 展开更多
关键词 Catchment clustering K-means WARD Self-Organized Map Wavelet–Entropy UTAH
下载PDF
The Effective Clustering Partition Algorithm Based on the Genetic Evolution 被引量:1
20
作者 廖芹 李希雯 《Journal of Donghua University(English Edition)》 EI CAS 2006年第6期43-46,共4页
To the problem that it is hard to determine the clustering number and the abnormal points by using the clustering validity function, an effective clustering partition model based on the genetic algorithm is built in t... To the problem that it is hard to determine the clustering number and the abnormal points by using the clustering validity function, an effective clustering partition model based on the genetic algorithm is built in this paper. The solution to the problem is formed by the combination of the clustering partition and the encoding samples, and the fitness function is defined by the distances among and within clusters. The clustering number and the samples in each cluster are determined and the abnormal points are distinguished by implementing the triple random crossover operator and the mutation. Based on the known sample data, the results of the novel method and the clustering validity function are compared. Numerical experiments are given and the results show that the novel method is more effective. 展开更多
关键词 clustering validity genetic algorithm clustering number abnormal point.
下载PDF
上一页 1 2 4 下一页 到第
使用帮助 返回顶部