Groundwater is a crucial water source for urban areas in Africa, particularly where surface water is insufficient to meet demand. This study analyses the water quality of five shallow wells (WW1-WW5) in Half-London Wa...Groundwater is a crucial water source for urban areas in Africa, particularly where surface water is insufficient to meet demand. This study analyses the water quality of five shallow wells (WW1-WW5) in Half-London Ward, Tunduma Town, Tanzania, using Principal Component Analysis (PCA) to identify the primary factors influencing groundwater contamination. Monthly samples were collected over 12 months and analysed for physical, chemical, and biological parameters. The PCA revealed between four and six principal components (PCs) for each well, explaining between 84.61% and 92.55% of the total variance in water quality data. In WW1, five PCs captured 87.53% of the variability, with PC1 (33.05%) dominated by pH, EC, TDS, and microbial contamination, suggesting significant influences from surface runoff and pit latrines. In WW2, six PCs explained 92.55% of the variance, with PC1 (36.17%) highlighting the effects of salinity, TDS, and agricultural runoff. WW3 had four PCs explaining 84.61% of the variance, with PC1 (39.63%) showing high contributions from pH, hardness, and salinity, indicating geological influences and contamination from human activities. Similarly, in WW4, six PCs explained 90.83% of the variance, where PC1 (43.53%) revealed contamination from pit latrines and fertilizers. WW5 also had six PCs, accounting for 92.51% of the variance, with PC1 (42.73%) indicating significant contamination from agricultural runoff and pit latrines. The study concludes that groundwater quality in Half-London Ward is primarily affected by a combination of surface runoff, pit latrine contamination, agricultural inputs, and geological factors. The presence of microbial contaminants and elevated nitrate and phosphate levels underscores the need for improved sanitation and sustainable agricultural practices. Recommendations include strengthening sanitation infrastructure, promoting responsible farming techniques, and implementing regular groundwater monitoring to safeguard water resources and public health in the region.展开更多
Understanding the ecological evolution is of great significance in addressing the impacts of climate change and human activities.However,the ecological evolution and its drivers remain inadequately explored in arid an...Understanding the ecological evolution is of great significance in addressing the impacts of climate change and human activities.However,the ecological evolution and its drivers remain inadequately explored in arid and semi-arid areas.This study took the Helan Mountain,a typical arid and semi-arid area in China,as the study area.By adopting an Enhanced Remote Sensing Ecological Index(ERSEI)that integrates the habitat quality(HQ)index with the Remote Sensing Ecological Index(RSEI),we quantified the ecological environment quality of the Helan Mountain during 2010-2022 and analyzed the driving factors behind the changes.Principal Component Analysis(PCA)was used to validate the composite ERSEI,enabling the extraction of key features and the reduction of redundant information.The results showed that the contributions of first principal component(PC1)for ERSEI and RSEI were 80.23%and 78.72%,respectively,indicating that the ERSEI can provide higher precision and more details than the RSEI in assessing ecological environment quality.Temporally,the ERSEI in the Helan Mountain exhibited an initial decline followed by an increase from 2010 to 2022,with the average value of ERSEI ranging between 0.298 and 0.346.Spatially,the ERSEI showed a trend of being higher in the southwest and lower in the northeast,with high-quality ecological environments mainly concentrated in the western foothills at higher altitudes.The centroid of ERSEI shifted northeastward toward Helan County from 2010 to 2022.Temperature and digital elevation model(DEM)emerged as the primary drivers of ERSEI changes.This study highlights the necessity of using comprehensive monitoring tools to guide policy-making and conservation strategies,ensuring the resilience of fragile ecosystems in the face of ongoing climatic and anthropogenic pressures.The findings offer valuable insights for the sustainable management and conservation in arid and semi-arid ecosystems.展开更多
Texture qualities of cooked rice are comprised of many indexes with the complex relationship, so it is difficult to analyze and evaluate cooked rice. In this paper, the related indexes of texture properties were conve...Texture qualities of cooked rice are comprised of many indexes with the complex relationship, so it is difficult to analyze and evaluate cooked rice. In this paper, the related indexes of texture properties were conversed into the independent indexes of principal component based on the principal component analysis method. The results showed that the rice kernel types influenced the meanings of principal components indexes. For long and short rice, the first principal component was comprehensive index. But the second principal component was springiness for the short rice, while it was adhesiveness for long rice. Therefore, the first principal component can be used to express the quality of cooked rice with a few of indexes, and the rice type can be recognized according to the second principal component.展开更多
Due to the scarcity of resources of Ziziphi spinosae semen （ZSS）, many inferior goods and even adulterants are generally found in medicine markets. To strengthen the quality control, HPLC fingerprint common pattern ...Due to the scarcity of resources of Ziziphi spinosae semen （ZSS）, many inferior goods and even adulterants are generally found in medicine markets. To strengthen the quality control, HPLC fingerprint common pattern established in this paper showed three main bioactive compounds in one chromatogram simultaneously. Principal component analysis based on DAD signals could discriminate adulterants and inferiorities. Principal component analysis indicated that all samples could be mainly regrouped into two main clusters according to the first principal component （PC1, redefined as Vicenin II） and the second principal component （PC2, redefined as zizyphusine）. PC1 and PC2 could explain 91.42%of the variance. Content of zizyphusine fluctuated more greatly than that of spinosin, and this result was also confirmed by the HPTLC result. Samples with low content of jujubosides and two common adulterants could not be used equivalently with authenticated ones in clinic, while one reference standard extract could substitute the crude drug in pharmaceutical production. Giving special consideration to the well-known bioactive saponins but with low response by end absorption, a fast and cheap HPTLC method for quality control of ZSS was developed and the result obtained was commensurate well with that of HPLC analysis. Samples having similar fingerprints to HPTLC common pattern targeting at saponins could be regarded as authenticated ones. This work provided a faster and cheaper way for quality control of ZSS and laid foundation for establishing a more effective quality control method for ZSS.展开更多
The water pollution situation in Balihe Lake, the biggest tributary of Shaying River Basin in Anhui Province, China, has brought a huge pressure on the improvement of water quality in Huai River. On October 16th, 2017...The water pollution situation in Balihe Lake, the biggest tributary of Shaying River Basin in Anhui Province, China, has brought a huge pressure on the improvement of water quality in Huai River. On October 16th, 2017, 11 major pollution indexes were observed at 15 sampling points in Balihe Lake. Based on the data experimentally measured, the water quality in Balihe Lake was analyzed utilizing the Principal Component Analysis (PCA) of SPSS. The result suggested that the major components were oxygenated pollutants, water eutrophication pollutants and ammonia nitrogen, in which oxygenated pollutants played a dominant role. In addition, the upper part of Balihe Lake suffered serious situation and needed a focus on oxygenated pollutants.展开更多
5 critical quality characteristics must be controlled in the surface mount and wire-bond process in semiconductor packaging. And these characteristics are correlated with each other. So the principal components analy...5 critical quality characteristics must be controlled in the surface mount and wire-bond process in semiconductor packaging. And these characteristics are correlated with each other. So the principal components analysis（PCA） is used in the analysis of the sample data firstly. And then the process is controlled with hotelling T^2 control chart for the first several principal components which contain sufficient information. Furthermore, a software tool is developed for this kind of problems. And with sample data from a surface mounting device（SMD） process, it is demonstrated that the T^2 control chart with PCA gets the same conclusion as without PCA, but the problem is transformed from high-dimensional one to a lower dimensional one, i.e., from 5 to 2 in this demonstration.展开更多
Six rice quality traits of 47 rice varieties approved in Ningxia in past 25 years were analyzed. The results showed that there was complicated correlation between rice quality traits. Through the principal component a...Six rice quality traits of 47 rice varieties approved in Ningxia in past 25 years were analyzed. The results showed that there was complicated correlation between rice quality traits. Through the principal component analysis using 6 × 6 order correlation matrix, five principal components with different meanings were obtained. The accumulative contribution rate of the first five characteristic roots was as high as 96.04%. Furthermore, the five principal components could cluster the 47 varieties into seven groups. The first group performed the best in quality traits, followed by the second group and the third group taking the second place, and then the fourth, seventh, fifth and sixth groups, sequentially. The clustering pedigree chart showed that only the varieties among the 47 tested varieties, which performed better in chalky kernel percentage and chalkiness degree, could become dominant varieties with extension value. This indicates that chalky kernel percentage and chalkiness degree are main factors restricting rice quality.展开更多
Survey and analysis were conducted on water quality of offshore seas in eastern region of Shenzhen by principal component analysis with SPSS. Then, 8 pollutants indices were then reduced to 5. Based on weighted analys...Survey and analysis were conducted on water quality of offshore seas in eastern region of Shenzhen by principal component analysis with SPSS. Then, 8 pollutants indices were then reduced to 5. Based on weighted analysis of principal component weights, comprehensive scores of different monitored stations were com- puted and sequenced in order to make evaluation on sea quality of eastern region of Shenzhen.展开更多
Objective To understand the current semen quality status among Chinese young men and influential factors in China and to explore its evaluation index. Methods A total of 562 healthy male volunteers were recruited duri...Objective To understand the current semen quality status among Chinese young men and influential factors in China and to explore its evaluation index. Methods A total of 562 healthy male volunteers were recruited during their premarital examinations in seven provincials and municipal regions' MCH centers; descriptive and principal component analyses were used to analyze data.Results The findings show that semen volume (2. 61± 1. 10 mL), sperm density (64. 47× 34. 59× 106/mL), percentage of sperm forward progression (59. 89%± 17. 11%), percentage of sperm viability (77. 19% ± 11. 87%), and percentage of normal sperm morphology ( 78. 23% ± 9. 15% ). The first principal component function is Z1= -8.512 54 + 0. 001 35X1' + 0. 031 92X2'+0. 043 52X3'+ 0. 039 84X4', which is closely related to percentage of sperm viability (X3), percentage of sperm forward progression (X2), and percentage of normal sperm morphology (X4)The second principal component function is: Z2= 0. 491 92+ 0. 080 80X1- 0. 000 58X2-0. 005 10X3- 0. 018 07X4, which depends on the total sperm count (X1). Conclusion Only 42. 3% subjects meet all the common WHO standard of semen quality. The multiple analysis of Z1 showed that the highest Z1 are among subjects from Guizhou,workers, or town residents. Multiple analysis of Z2 showed that the older age when the subjects had the first sexual impulse, the longer period of sexual abstinence and more quantity of sperm they had; the more sexual activity subjects had, the less amount of sperm they had.展开更多
Commonly, seismic data processing procedures, such as stacking and prestack migration, require the ability to detect bad traces/shots and restore or replace them by interpolation, particularly when the seismic observa...Commonly, seismic data processing procedures, such as stacking and prestack migration, require the ability to detect bad traces/shots and restore or replace them by interpolation, particularly when the seismic observations are noisy or there are malfunctioned components in the recording system. However, currently available trace/shot interpolation methods in the spatial or Fourier domain must deal with requirements such as evenly sampled traces/shots, infinite bandwidth of the signals, and linear seismic events. In this paper, we present a novel method, termed the E-S (eigenspace seismic) method, using principal component analysis (PCA) of the seismic signal to address the issue of reliable detection or interpolation of bad traces/shots. The E-S method assumes the existence of a correlation between the observed seismic entities, such as trace or shot gathers, making it possible to estimate one of these entities from all others for interpolation or seismic quality control. It first transforms a trace (or shot) gather into an eigenspace using PCA. Then in the eigenspace, it treats every trace as a point with its loading scores of PCA as its coordinates. Simple linear, bilinear, or cubic spline 1 dimensional (1D) interpolation is used to determine PCA loading scores for any arbitrary coordinate in the eigenspace, which are then used to construct an interpolated trace for the desired position in physical space. This E-S method works with either regular or irregular sampling and, unlike various other published methods, it is well-suited for band-limited seismic records with curvilinear reflection events. We developed related algorithms and applied these to processed synthetic and offshore seismic survey data with or without simulated noises to demonstrate their performance. By comparing the interpolated and observed seismic traces, we find that the E-S method can effectively assess the quality of the trace, and restore poor quality data by interpolation. The successful processing of synthetic and real data using the E-S method presented in this approach will be widely applicable to seismic trace/shot interpolation and seismic quality control.展开更多
In this paper, we conduct research on the large-scale network intrusion mode based on the principal component analysis and dropquality sampling. With the growing of network security issues, invasion detection becomes ...In this paper, we conduct research on the large-scale network intrusion mode based on the principal component analysis and dropquality sampling. With the growing of network security issues, invasion detection becomes the study hotspot. There are two main types of thatinvasion detection technology, the fi rst is that misuse detection and the anomaly detection. Misuse detection can more accurately detect attacks,but high non-response rates, anomaly detection could detect the unknown attacks, but higher rate of false positives. Network invasion detectionproblem is summed up in the network data fl ow of discriminant problem, namely the judgment of network data fl ow is normal or malicious andin this sense here invasion detection problem can be understood as a pattern recognition problem. Our research integrates the PCA and samplingtechnique to propose the new idea on the IDS that is innovative and will promote the development of the corresponding techniques.展开更多
Existing Web service selection approaches usually assume that preferences of users have been provided in a quantitative form by users. However, due to the subjectivity and vagueness of preferences, it may be impractic...Existing Web service selection approaches usually assume that preferences of users have been provided in a quantitative form by users. However, due to the subjectivity and vagueness of preferences, it may be impractical for users to specify quantitative and exact preferences. Moreover, due to that Quality of Service (QoS) attributes are often interrelated, existing Web service selection approaches which employ weighted summation of QoS attribute values to compute the overall QoS of Web services may produce inaccurate results, since they do not take correlations among QoS attributes into account. To resolve these problems, a Web service selection framework considering user's preference priority is proposed, which incorporates a searching mechanism with QoS range setting to identify services satisfying the user's QoS constraints. With the identified service candidates, based on the idea of Principal Component Analysis (PCA), an algorithm of Web service selection named PCA-WSS (Web Service Selection based on PCA) is proposed, which can eliminate the correlations among QoS attributes and compute the overall QoS of Web services accurately. After computing the overall QoS for each service, the algorithm ranks the Web service candidates based on their overall QoS and recommends services with top QoS values to users. Finally, the effectiveness and feasibility of our approach are validated by experiments, i.e. the selected Web service by our approach is given high average evaluation than other ones by users and the time cost of PCA-WSS algorithm is not affected acutely by the number of service candidates.展开更多
This paper brings forward a novel dynamic multiple access network selection scheme(NDMAS),which could achieve less energy loss and improve the poor adaptive capability caused by the variable network parameters.Firstly...This paper brings forward a novel dynamic multiple access network selection scheme(NDMAS),which could achieve less energy loss and improve the poor adaptive capability caused by the variable network parameters.Firstly,a multiple access network selection mathematical model based on information theory is presented.From the perspective of information theory,access selection is essentially a process to reduce the information entropy in the system.It can be found that the lower the information entropy is,the better the system performance fulfills.Therefore,this model is designed to reduce the information entropy by removing redundant parameters,and to avoid the computational cost as well.Secondly,for model implementation,the Principal Component Analysis(PCA) is employed to process the observation data to find out the related factors which affect the users most.As a result,the information entropy is decreased.Theoretical analysis proves that system loss and computational complexity have been decreased by using the proposed approach,while the network QoS and accuracy are guaranteed.Finally,simulation results show that our scheme achieves much better system performance in terms of packet delay,throughput and call blocking probability than other currently existing ones.展开更多
[Objectives] This study conducted investigations on the climate and soil nutrients of different chestnut orchards in the Yanshan region, selected key ecological factors affecting the growth and fruit quality of chestn...[Objectives] This study conducted investigations on the climate and soil nutrients of different chestnut orchards in the Yanshan region, selected key ecological factors affecting the growth and fruit quality of chestnuts, and provided a theoretical basis for the cultivation, introduction, and scientific planting of high-quality chestnuts. [Methods] The ‘Yanshanzaofeng’ chestnuts in four orchards located in Qianxi, Qianan, Funing, and Qinglong of Hebei Science and Technology Normal University were selected. The climate and soil nutrient conditions of the four orchards were investigated. Growth indicators such as branch length and diameter, nut weight, and internal quality indicators such as starch, fat, and protein content were analyzed. Principal component analysis was conducted on nine climate factors and twelve soil factors in the four chestnut orchards to identify the most closely related ecological factors influencing chestnut growth and quality. [Results] (i) Different orchards had varying climate conditions, with Qianan orchard having higher rainfall than the others, Funing orchard having the highest number of sunshine hours in the growing season, and Qinglong orchard experiencing the greatest temperature difference during the growing season. (ii) Significant differences were found in soil nutrient content among the orchards, with the coefficient of variation for organic matter and mineral elements ranging from 19.1% (S) to 80.3% (available phosphorus). (iii) The main ecological factor influencing chestnut growth was the photosynthetic factor, while fruit quality was influenced by a combination of climatic factors, photosynthetic factors, and nutrient factors. Key ecological factor indicators included: annual precipitation, annual sunshine hours, growing season precipitation, growing season sunshine hours, soil organic matter, available phosphorus, available potassium, alkali nitrogen, copper, zinc, available boron, and sulfur. Soluble solids were significantly positively correlated with growing season sunshine hours, and fat was significantly positively correlated with available potassium and alkali nitrogen, and significantly positively correlated with available phosphorus. [Conclusions] Orchards with high growing season precipitation, long sunshine hours, and high organic matter and nitrogen-phosphorus-potassium content in the soil are more conducive to promoting the growth of ‘Yanshanzaofeng’ chestnuts and improving fruit quality.展开更多
Since the founding of the People’s Republic of China in 1949,the Communist Party of China(CPC)has separated China’s evolving principal social contradictions into four different stages.Based on the assessment of prin...Since the founding of the People’s Republic of China in 1949,the Communist Party of China(CPC)has separated China’s evolving principal social contradictions into four different stages.Based on the assessment of principal social contradictions at different points in time,the CPC enacted different economic policies.During 1949-1956,based on the recognition of class struggle as China’s principal social contradiction,the Party focused its economic policies on socialist transformation and established the foundation for the public sector of the economy.During 1956-1978,amid flip-flops in the Party’s assessment of whether class struggle or backward productive forces were the principal contradiction,China’s economic development suffered some setbacks,but the vision for building an industrial country remained unchanged,and resources were focused on developing major national industrial projects.During 1978-2019,the Party focused on economic development and reform and opening up in pursuit of the realization of grand economic development goals based on the assessment that China’s principal social contradiction was between people’s ever-growing material and cultural needs and China’s relatively backward social productive forces.In 2017,the 19th CPC National Congress made the important political assessment that China’s principal social contradiction had transformed into the contradiction between people’s ever-growing need for a better life and China’s unbalanced and inadequate development,and proposed new development concepts to lead the Chinese people on a new journey towards the second centennial goal.The most important experience of the CPC’s economic work is analyzing and solving problems based on Marxist ideology and methodology.展开更多
文摘Groundwater is a crucial water source for urban areas in Africa, particularly where surface water is insufficient to meet demand. This study analyses the water quality of five shallow wells (WW1-WW5) in Half-London Ward, Tunduma Town, Tanzania, using Principal Component Analysis (PCA) to identify the primary factors influencing groundwater contamination. Monthly samples were collected over 12 months and analysed for physical, chemical, and biological parameters. The PCA revealed between four and six principal components (PCs) for each well, explaining between 84.61% and 92.55% of the total variance in water quality data. In WW1, five PCs captured 87.53% of the variability, with PC1 (33.05%) dominated by pH, EC, TDS, and microbial contamination, suggesting significant influences from surface runoff and pit latrines. In WW2, six PCs explained 92.55% of the variance, with PC1 (36.17%) highlighting the effects of salinity, TDS, and agricultural runoff. WW3 had four PCs explaining 84.61% of the variance, with PC1 (39.63%) showing high contributions from pH, hardness, and salinity, indicating geological influences and contamination from human activities. Similarly, in WW4, six PCs explained 90.83% of the variance, where PC1 (43.53%) revealed contamination from pit latrines and fertilizers. WW5 also had six PCs, accounting for 92.51% of the variance, with PC1 (42.73%) indicating significant contamination from agricultural runoff and pit latrines. The study concludes that groundwater quality in Half-London Ward is primarily affected by a combination of surface runoff, pit latrine contamination, agricultural inputs, and geological factors. The presence of microbial contaminants and elevated nitrate and phosphate levels underscores the need for improved sanitation and sustainable agricultural practices. Recommendations include strengthening sanitation infrastructure, promoting responsible farming techniques, and implementing regular groundwater monitoring to safeguard water resources and public health in the region.
基金funded by the Fujian Province's Foreign Cooperation Project in 2023(2023I0047)the Fujian Provincial Natural Science Foundation Project(2023J011432,2024J011195)+3 种基金the Ministry of Education's Supply-demand Docking Employment and Education Project(2024011223947)the Open Project Fund of Hunan Provincial Key Laboratory for Remote Sensing Monitoring of Ecological Environment in Dongting Lake Area(DTH Key Lab.2024-04,2022-04)the Fujian Provincial Natural Science Foundation Guiding Project(2024Y0057)the Fujian Province Social Science Plan Project(FJ2024BF071).
文摘Understanding the ecological evolution is of great significance in addressing the impacts of climate change and human activities.However,the ecological evolution and its drivers remain inadequately explored in arid and semi-arid areas.This study took the Helan Mountain,a typical arid and semi-arid area in China,as the study area.By adopting an Enhanced Remote Sensing Ecological Index(ERSEI)that integrates the habitat quality(HQ)index with the Remote Sensing Ecological Index(RSEI),we quantified the ecological environment quality of the Helan Mountain during 2010-2022 and analyzed the driving factors behind the changes.Principal Component Analysis(PCA)was used to validate the composite ERSEI,enabling the extraction of key features and the reduction of redundant information.The results showed that the contributions of first principal component(PC1)for ERSEI and RSEI were 80.23%and 78.72%,respectively,indicating that the ERSEI can provide higher precision and more details than the RSEI in assessing ecological environment quality.Temporally,the ERSEI in the Helan Mountain exhibited an initial decline followed by an increase from 2010 to 2022,with the average value of ERSEI ranging between 0.298 and 0.346.Spatially,the ERSEI showed a trend of being higher in the southwest and lower in the northeast,with high-quality ecological environments mainly concentrated in the western foothills at higher altitudes.The centroid of ERSEI shifted northeastward toward Helan County from 2010 to 2022.Temperature and digital elevation model(DEM)emerged as the primary drivers of ERSEI changes.This study highlights the necessity of using comprehensive monitoring tools to guide policy-making and conservation strategies,ensuring the resilience of fragile ecosystems in the face of ongoing climatic and anthropogenic pressures.The findings offer valuable insights for the sustainable management and conservation in arid and semi-arid ecosystems.
基金Education Department of Heilongjiang Province in China for the Oversea Researcher Projects(1151HZ01,10531002)
文摘Texture qualities of cooked rice are comprised of many indexes with the complex relationship, so it is difficult to analyze and evaluate cooked rice. In this paper, the related indexes of texture properties were conversed into the independent indexes of principal component based on the principal component analysis method. The results showed that the rice kernel types influenced the meanings of principal components indexes. For long and short rice, the first principal component was comprehensive index. But the second principal component was springiness for the short rice, while it was adhesiveness for long rice. Therefore, the first principal component can be used to express the quality of cooked rice with a few of indexes, and the rice type can be recognized according to the second principal component.
文摘Due to the scarcity of resources of Ziziphi spinosae semen （ZSS）, many inferior goods and even adulterants are generally found in medicine markets. To strengthen the quality control, HPLC fingerprint common pattern established in this paper showed three main bioactive compounds in one chromatogram simultaneously. Principal component analysis based on DAD signals could discriminate adulterants and inferiorities. Principal component analysis indicated that all samples could be mainly regrouped into two main clusters according to the first principal component （PC1, redefined as Vicenin II） and the second principal component （PC2, redefined as zizyphusine）. PC1 and PC2 could explain 91.42%of the variance. Content of zizyphusine fluctuated more greatly than that of spinosin, and this result was also confirmed by the HPTLC result. Samples with low content of jujubosides and two common adulterants could not be used equivalently with authenticated ones in clinic, while one reference standard extract could substitute the crude drug in pharmaceutical production. Giving special consideration to the well-known bioactive saponins but with low response by end absorption, a fast and cheap HPTLC method for quality control of ZSS was developed and the result obtained was commensurate well with that of HPLC analysis. Samples having similar fingerprints to HPTLC common pattern targeting at saponins could be regarded as authenticated ones. This work provided a faster and cheaper way for quality control of ZSS and laid foundation for establishing a more effective quality control method for ZSS.
文摘The water pollution situation in Balihe Lake, the biggest tributary of Shaying River Basin in Anhui Province, China, has brought a huge pressure on the improvement of water quality in Huai River. On October 16th, 2017, 11 major pollution indexes were observed at 15 sampling points in Balihe Lake. Based on the data experimentally measured, the water quality in Balihe Lake was analyzed utilizing the Principal Component Analysis (PCA) of SPSS. The result suggested that the major components were oxygenated pollutants, water eutrophication pollutants and ammonia nitrogen, in which oxygenated pollutants played a dominant role. In addition, the upper part of Balihe Lake suffered serious situation and needed a focus on oxygenated pollutants.
基金This project is supported by National Natural Science Foundation of China (No.70372062)Hi-Tech Program of Tianjin city,China (No.04310881R).
文摘5 critical quality characteristics must be controlled in the surface mount and wire-bond process in semiconductor packaging. And these characteristics are correlated with each other. So the principal components analysis（PCA） is used in the analysis of the sample data firstly. And then the process is controlled with hotelling T^2 control chart for the first several principal components which contain sufficient information. Furthermore, a software tool is developed for this kind of problems. And with sample data from a surface mounting device（SMD） process, it is demonstrated that the T^2 control chart with PCA gets the same conclusion as without PCA, but the problem is transformed from high-dimensional one to a lower dimensional one, i.e., from 5 to 2 in this demonstration.
基金Supported by Natural Science Foundation of Ningxia Province(NZ17187)New Rice Variety BreedingScientific and Technological Innovation of Ningxia Academy of Agro-forestry Sciences(NKYJ-16-14,NKYJ-18-15-3)
文摘Six rice quality traits of 47 rice varieties approved in Ningxia in past 25 years were analyzed. The results showed that there was complicated correlation between rice quality traits. Through the principal component analysis using 6 × 6 order correlation matrix, five principal components with different meanings were obtained. The accumulative contribution rate of the first five characteristic roots was as high as 96.04%. Furthermore, the five principal components could cluster the 47 varieties into seven groups. The first group performed the best in quality traits, followed by the second group and the third group taking the second place, and then the fourth, seventh, fifth and sixth groups, sequentially. The clustering pedigree chart showed that only the varieties among the 47 tested varieties, which performed better in chalky kernel percentage and chalkiness degree, could become dominant varieties with extension value. This indicates that chalky kernel percentage and chalkiness degree are main factors restricting rice quality.
文摘Survey and analysis were conducted on water quality of offshore seas in eastern region of Shenzhen by principal component analysis with SPSS. Then, 8 pollutants indices were then reduced to 5. Based on weighted analysis of principal component weights, comprehensive scores of different monitored stations were com- puted and sequenced in order to make evaluation on sea quality of eastern region of Shenzhen.
文摘Objective To understand the current semen quality status among Chinese young men and influential factors in China and to explore its evaluation index. Methods A total of 562 healthy male volunteers were recruited during their premarital examinations in seven provincials and municipal regions' MCH centers; descriptive and principal component analyses were used to analyze data.Results The findings show that semen volume (2. 61± 1. 10 mL), sperm density (64. 47× 34. 59× 106/mL), percentage of sperm forward progression (59. 89%± 17. 11%), percentage of sperm viability (77. 19% ± 11. 87%), and percentage of normal sperm morphology ( 78. 23% ± 9. 15% ). The first principal component function is Z1= -8.512 54 + 0. 001 35X1' + 0. 031 92X2'+0. 043 52X3'+ 0. 039 84X4', which is closely related to percentage of sperm viability (X3), percentage of sperm forward progression (X2), and percentage of normal sperm morphology (X4)The second principal component function is: Z2= 0. 491 92+ 0. 080 80X1- 0. 000 58X2-0. 005 10X3- 0. 018 07X4, which depends on the total sperm count (X1). Conclusion Only 42. 3% subjects meet all the common WHO standard of semen quality. The multiple analysis of Z1 showed that the highest Z1 are among subjects from Guizhou,workers, or town residents. Multiple analysis of Z2 showed that the older age when the subjects had the first sexual impulse, the longer period of sexual abstinence and more quantity of sperm they had; the more sexual activity subjects had, the less amount of sperm they had.
文摘Commonly, seismic data processing procedures, such as stacking and prestack migration, require the ability to detect bad traces/shots and restore or replace them by interpolation, particularly when the seismic observations are noisy or there are malfunctioned components in the recording system. However, currently available trace/shot interpolation methods in the spatial or Fourier domain must deal with requirements such as evenly sampled traces/shots, infinite bandwidth of the signals, and linear seismic events. In this paper, we present a novel method, termed the E-S (eigenspace seismic) method, using principal component analysis (PCA) of the seismic signal to address the issue of reliable detection or interpolation of bad traces/shots. The E-S method assumes the existence of a correlation between the observed seismic entities, such as trace or shot gathers, making it possible to estimate one of these entities from all others for interpolation or seismic quality control. It first transforms a trace (or shot) gather into an eigenspace using PCA. Then in the eigenspace, it treats every trace as a point with its loading scores of PCA as its coordinates. Simple linear, bilinear, or cubic spline 1 dimensional (1D) interpolation is used to determine PCA loading scores for any arbitrary coordinate in the eigenspace, which are then used to construct an interpolated trace for the desired position in physical space. This E-S method works with either regular or irregular sampling and, unlike various other published methods, it is well-suited for band-limited seismic records with curvilinear reflection events. We developed related algorithms and applied these to processed synthetic and offshore seismic survey data with or without simulated noises to demonstrate their performance. By comparing the interpolated and observed seismic traces, we find that the E-S method can effectively assess the quality of the trace, and restore poor quality data by interpolation. The successful processing of synthetic and real data using the E-S method presented in this approach will be widely applicable to seismic trace/shot interpolation and seismic quality control.
文摘In this paper, we conduct research on the large-scale network intrusion mode based on the principal component analysis and dropquality sampling. With the growing of network security issues, invasion detection becomes the study hotspot. There are two main types of thatinvasion detection technology, the fi rst is that misuse detection and the anomaly detection. Misuse detection can more accurately detect attacks,but high non-response rates, anomaly detection could detect the unknown attacks, but higher rate of false positives. Network invasion detectionproblem is summed up in the network data fl ow of discriminant problem, namely the judgment of network data fl ow is normal or malicious andin this sense here invasion detection problem can be understood as a pattern recognition problem. Our research integrates the PCA and samplingtechnique to propose the new idea on the IDS that is innovative and will promote the development of the corresponding techniques.
基金Supported by the National Natural Science Foundation of China(No.90818004and61100054)Program for New Century Excellent Talents in University(No.NCET-10-0140)+1 种基金Excellent Youth Foundation of Hunan Scientific Committee(No.11JJ1011)Scientific Research Fundof Hunan Educational Committee(No.09K085and11B048)
文摘Existing Web service selection approaches usually assume that preferences of users have been provided in a quantitative form by users. However, due to the subjectivity and vagueness of preferences, it may be impractical for users to specify quantitative and exact preferences. Moreover, due to that Quality of Service (QoS) attributes are often interrelated, existing Web service selection approaches which employ weighted summation of QoS attribute values to compute the overall QoS of Web services may produce inaccurate results, since they do not take correlations among QoS attributes into account. To resolve these problems, a Web service selection framework considering user's preference priority is proposed, which incorporates a searching mechanism with QoS range setting to identify services satisfying the user's QoS constraints. With the identified service candidates, based on the idea of Principal Component Analysis (PCA), an algorithm of Web service selection named PCA-WSS (Web Service Selection based on PCA) is proposed, which can eliminate the correlations among QoS attributes and compute the overall QoS of Web services accurately. After computing the overall QoS for each service, the algorithm ranks the Web service candidates based on their overall QoS and recommends services with top QoS values to users. Finally, the effectiveness and feasibility of our approach are validated by experiments, i.e. the selected Web service by our approach is given high average evaluation than other ones by users and the time cost of PCA-WSS algorithm is not affected acutely by the number of service candidates.
基金supported by National Natural Science Foundation of China under Grant No.60971083National International Science and Technology Cooperation Project of China (No.2010DFA11320)
文摘This paper brings forward a novel dynamic multiple access network selection scheme(NDMAS),which could achieve less energy loss and improve the poor adaptive capability caused by the variable network parameters.Firstly,a multiple access network selection mathematical model based on information theory is presented.From the perspective of information theory,access selection is essentially a process to reduce the information entropy in the system.It can be found that the lower the information entropy is,the better the system performance fulfills.Therefore,this model is designed to reduce the information entropy by removing redundant parameters,and to avoid the computational cost as well.Secondly,for model implementation,the Principal Component Analysis(PCA) is employed to process the observation data to find out the related factors which affect the users most.As a result,the information entropy is decreased.Theoretical analysis proves that system loss and computational complexity have been decreased by using the proposed approach,while the network QoS and accuracy are guaranteed.Finally,simulation results show that our scheme achieves much better system performance in terms of packet delay,throughput and call blocking probability than other currently existing ones.
基金Supported by Sub-project of National Key Research and Development Program of China(2022YFD2200405-4)。
文摘[Objectives] This study conducted investigations on the climate and soil nutrients of different chestnut orchards in the Yanshan region, selected key ecological factors affecting the growth and fruit quality of chestnuts, and provided a theoretical basis for the cultivation, introduction, and scientific planting of high-quality chestnuts. [Methods] The ‘Yanshanzaofeng’ chestnuts in four orchards located in Qianxi, Qianan, Funing, and Qinglong of Hebei Science and Technology Normal University were selected. The climate and soil nutrient conditions of the four orchards were investigated. Growth indicators such as branch length and diameter, nut weight, and internal quality indicators such as starch, fat, and protein content were analyzed. Principal component analysis was conducted on nine climate factors and twelve soil factors in the four chestnut orchards to identify the most closely related ecological factors influencing chestnut growth and quality. [Results] (i) Different orchards had varying climate conditions, with Qianan orchard having higher rainfall than the others, Funing orchard having the highest number of sunshine hours in the growing season, and Qinglong orchard experiencing the greatest temperature difference during the growing season. (ii) Significant differences were found in soil nutrient content among the orchards, with the coefficient of variation for organic matter and mineral elements ranging from 19.1% (S) to 80.3% (available phosphorus). (iii) The main ecological factor influencing chestnut growth was the photosynthetic factor, while fruit quality was influenced by a combination of climatic factors, photosynthetic factors, and nutrient factors. Key ecological factor indicators included: annual precipitation, annual sunshine hours, growing season precipitation, growing season sunshine hours, soil organic matter, available phosphorus, available potassium, alkali nitrogen, copper, zinc, available boron, and sulfur. Soluble solids were significantly positively correlated with growing season sunshine hours, and fat was significantly positively correlated with available potassium and alkali nitrogen, and significantly positively correlated with available phosphorus. [Conclusions] Orchards with high growing season precipitation, long sunshine hours, and high organic matter and nitrogen-phosphorus-potassium content in the soil are more conducive to promoting the growth of ‘Yanshanzaofeng’ chestnuts and improving fruit quality.
文摘Since the founding of the People’s Republic of China in 1949,the Communist Party of China(CPC)has separated China’s evolving principal social contradictions into four different stages.Based on the assessment of principal social contradictions at different points in time,the CPC enacted different economic policies.During 1949-1956,based on the recognition of class struggle as China’s principal social contradiction,the Party focused its economic policies on socialist transformation and established the foundation for the public sector of the economy.During 1956-1978,amid flip-flops in the Party’s assessment of whether class struggle or backward productive forces were the principal contradiction,China’s economic development suffered some setbacks,but the vision for building an industrial country remained unchanged,and resources were focused on developing major national industrial projects.During 1978-2019,the Party focused on economic development and reform and opening up in pursuit of the realization of grand economic development goals based on the assessment that China’s principal social contradiction was between people’s ever-growing material and cultural needs and China’s relatively backward social productive forces.In 2017,the 19th CPC National Congress made the important political assessment that China’s principal social contradiction had transformed into the contradiction between people’s ever-growing need for a better life and China’s unbalanced and inadequate development,and proposed new development concepts to lead the Chinese people on a new journey towards the second centennial goal.The most important experience of the CPC’s economic work is analyzing and solving problems based on Marxist ideology and methodology.
