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Initial and Stopping Condition in Possibility Principal Factor Rotation
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作者 Houju Hori Jr. 《Journal of Applied Mathematics and Physics》 2023年第5期1482-1486,共5页
Uemura [1] discovered the mapping formula for Type 1 Vague events and presented an alternative problem as an example of its application. Since it is well known that the alternative problem leads to sequential Bayesian... Uemura [1] discovered the mapping formula for Type 1 Vague events and presented an alternative problem as an example of its application. Since it is well known that the alternative problem leads to sequential Bayesian inference, the flow of subsequent research was to make the mapping formula multidimensional, to introduce the concept of time, and to derive a Markov (decision) process. Furthermore, we formulated stochastic differential equations to derive them [2]. This paper refers to type 2 vague events based on a second-order mapping equation. This quadratic mapping formula gives a certain rotation named as possibility principal factor rotation by transforming a non-mapping function by a relation between two mapping functions. In addition, the derivation of the Type 2 Complex Markov process and the initial and stopping conditions in this rotation are mentioned. . 展开更多
关键词 Extension principle Vague Event Type 2 Possibility Different Equation Possibility principal factor Analysis Initial and Stopping Condition
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Experimental study on failure characteristics of single-sided unloading rock under different intermediate principal stress conditions 被引量:9
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作者 Chongyan Liu Guangming Zhao +4 位作者 Wensong Xu Xiangrui Meng Zhixi Liu Xiang Cheng Gang Lin 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2023年第3期275-287,共13页
Investigation of unloading rock failure under differentσ_(2)facilitates the control mechanism of excavation surrounding rock.This study focused on single-sided unloading tests of granite specimens under true triaxial... Investigation of unloading rock failure under differentσ_(2)facilitates the control mechanism of excavation surrounding rock.This study focused on single-sided unloading tests of granite specimens under true triaxial conditions.The strength and failure characteristics were studied with micro-camera and acoustic emission(AE)monitoring.Furthermore,the choice of test path and the effect ofσ_(2)on fracture of unloading rock were discussed.Results show that the increasedσ_(2)can strengthen the stability of single-sided unloading rock.After unloading,the rock’s free surface underwent five phases,namely,inoculation,particle ejection,buckling rupture,stable failure,and unstable rockburst phases.Moreover,atσ_(2)≤30 MPa,the b value shows the following variation tendency:rising,dropping,significant fluctuation,and dropping,with dispersed damages signal.Atσ_(2)≥40 MPa,the tendency shows:a rise,a decrease,a slight fluctuation,and final drop,with concentrated damages signal.After unloading,AE energy is mainly concentrated in the micro-energy range.With the increasedσ_(2),the micro-energy ratio rises.In contrast,low,medium and large energy ratios drop gradually.The increased tensile fractures and decreased shear fractures indicate that the failure mode of the unloading rock gradually changes from tensile-shear mode to tensile-split one.The fractional dimension of the rock fragments first increases and then decreases with an inflection point at 20 MPa.The distribution of SIF on the planes changes asσ_(2)increases,resulting in strengthening and then weakening of the rock bearing capacity. 展开更多
关键词 Single-sided unloading Acoustic emission True triaxial Intermediate principal stress Stress intensity factor
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Risk Factors for Severity and Mortality of Patients Hospitalized for COVID-19 during the 3rd Wave of the Epidemic-Sao Tome and Principe
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作者 Eula Carvalho Bakissy Pina +3 位作者 Rosa Neto Wrceley Lima Vanderley Bandeira Leonilde Carvalho 《Advances in Infectious Diseases》 2023年第2期303-322,共20页
Rationale: In the literature, some risk factors for severity and mortality from COVID-19 have been indicated. However, these factors can change, depending on the characteristics of the population and health services. ... Rationale: In the literature, some risk factors for severity and mortality from COVID-19 have been indicated. However, these factors can change, depending on the characteristics of the population and health services. In this sense, longitudinal studies can be useful for understanding local realities and subsidizing health actions based on these realities. Objective: To analyze the risk factors for severity and death in hospitalized patients with COVID-19. Methods: A retrospective cohort of patients with COVID-19 hospitalized from August 1 to October 16, 2021 (3<sup>rd</sup> wave of the pandemic), notified by the Department of Epidemiological Surveillance of Sao Tome and Principe. We employed measures of strength of associations for the analysis of exposure risk factors. Results: We analyzed 110 hospitalized patients (31.8% severe-critical and 68.2% non-severe). The risk factors for severe forms of COVID-19 were: being aged ≥60 years (RR = 3.3), being male (RR = 2), having comorbidities (RR = 2) and the risk increases to 10-fold for multicomorbidities, with emphasis on obesity, neoplasia, skin-muscle-surgical infection, dementia and to some degree CVD. 62.9% of patients with severe forms of the disease were not vaccinated. Risk factors for death among hospitalized and severe/critical cases, respectively, were having comorbidities (RR = 8 and 2.4) multicomorbidities (RR = 10 and 2.8 for those with 2 comorbidities and RR = 33.3 and 4 for those with 3 or 4 comorbidities), especially diabetes, dementia, neoplasia, cutaneous-muscular infection, and obesity. Although CVD was not associated with risk factors for death, these were the most frequently found among the severely hospitalized and deaths. In addition, important risk factors associated with death were not using corticoids (RR = 3.3, 230-fold risk) and not using anticoagulants-heparin (RR = 1.3, 30% risk) more compared to the severe cases that did use them. Most of the patients who died (63.2%) were not vaccinated. Moreover, having only 1 dose of the vaccine was a risk factor 1.9 times more for death among all hospitalized patients, but in the severe cases, there was no association between the variable vaccination and death. Among those hospitalized with 2 doses, it was a 0.5-fold protective factor among those hospitalized. The Delta variant of Sarscov-2 was the one found among severe cases and deaths investigated by genetic sequencing, with more exuberant clinical features compared to the other 2 previous vaccinations. Conclusion: Being elderly, male and presenting comorbidities, mainly multicomorbidities were the main characteristics associated with severity of COVID-19. On the other hand, comorbidities, and even worse, multicomorbidities, hospitalization for respiratory failure, lowered level of consciousness, no use of corticoid and no use of anticoagulation in critically ill patients, and not having at least 2 doses of vaccine for covid-19, were characteristics associated with death by COVID-19. These results will help inform healthcare providers so that the best interventions can be implemented to improve outcomes for patients with COVID-19. Public health interventions must be carefully tailored and implemented in these susceptible groups to reduce the risk of mortality in patients with COVID-19 and then the risk of major complications. Intensive and regular follow-up is needed to detect early occurrences of clinical conditions. 展开更多
关键词 Covid-19 3rd Wave of the Epidemic Risk factors Death SEVERITY Sao Tomé and principe
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Effect of Two Kinds of Similarity Factors on Principal Component Analysis Fault Detection in Air Conditioning Systems 被引量:2
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作者 YANG Xuebin HE Ruru +1 位作者 WANG Ji LUO Wenjun 《Journal of Donghua University(English Edition)》 CAS 2021年第3期245-251,共7页
Screening similar historical fault-free candidate data would greatly affect the effectiveness of fault detection results based on principal component analysis(PCA).In order to find out the candidate data,this study co... Screening similar historical fault-free candidate data would greatly affect the effectiveness of fault detection results based on principal component analysis(PCA).In order to find out the candidate data,this study compares unweighted and weighted similarity factors(SFs),which measure the similarity of the principal component subspace corresponding to the first k main components of two datasets.The fault detection employs the principal component subspace corresponding to the current measured data and the historical fault-free data.From the historical fault-free database,the load parameters are employed to locate the candidate data similar to the current operating data.Fault detection method for air conditioning systems is based on principal component.The results show that the weighted principal component SF can improve the effects of the fault-free detection and the fault detection.Compared with the unweighted SF,the average fault-free detection rate of the weighted SF is 17.33%higher than that of the unweighted,and the average fault detection rate is 7.51%higher than unweighted. 展开更多
关键词 similarity factor(SF) fault detection principal component analysis(PCA) historical candidate data air conditioning system
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Evaluation on Land Ecological Security in Hohhot Based on Principal Component Analysis
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作者 侯林春 王瑛璇 《Agricultural Science & Technology》 CAS 2017年第7期1255-1259,共5页
Based on the status of land ecological resources in Hohhot, 20 indexes covering nature, resource environment, economy and society were selected and the evaluation index system was established. With the principal compo... Based on the status of land ecological resources in Hohhot, 20 indexes covering nature, resource environment, economy and society were selected and the evaluation index system was established. With the principal component analysis, the land ecological security of Hohhot from 2009 to 2015 was analyzed. The results showed that the land ecological security of Hohhot was declining year by year in 2009-2015. Besides, per capital GDP and public green area, the proportion of in- dustry and the price index of agricultural and animal husbandry production materials were the key factors influencing the land ecological security of Hohhot. The key for protection of the land ecological security may lie in the protection of land quality and prevention of land degradation in farming and stock-breeding areas. 展开更多
关键词 Land ecological security principal component factor COUNTERMEASURES Hohhot
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Statistical Monitoring of Chemical Processes Based on Sensitive Kernel Principal Components 被引量:10
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作者 JIANG Qingchao YAN Xuefeng 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2013年第6期633-643,共11页
The kernel principal component analysis (KPCA) method employs the first several kernel principal components (KPCs), which indicate the most variance information of normal observations for process monitoring, but m... The kernel principal component analysis (KPCA) method employs the first several kernel principal components (KPCs), which indicate the most variance information of normal observations for process monitoring, but may not reflect the fault information. In this study, sensitive kernel principal component analysis (SKPCA) is proposed to improve process monitoring performance, i.e., to deal with the discordance of T2 statistic and squared prediction error SVE statistic and reduce missed detection rates. T2 statistic can be used to measure the variation di rectly along each KPC and analyze the detection performance as well as capture the most useful information in a process. With the calculation of the change rate of T2 statistic along each KPC, SKPCA selects the sensitive kernel principal components for process monitoring. A simulated simple system and Tennessee Eastman process are employed to demonstrate the efficiency of SKPCA on online monitoring. The results indicate that the monitoring performance is improved significantly. 展开更多
关键词 statistical process monitoring kernel principal component analysis sensitive kernel principal compo-nent Tennessee Eastman process
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Leakage Rate Model of Urban Water Supply Networks Using Principal Component Regression Analysis 被引量:1
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作者 Zhiguang Niu Chong Wang +2 位作者 Ying Zhang Xiaoting Wei Xili Gao 《Transactions of Tianjin University》 EI CAS 2018年第2期172-181,共10页
To analyze the factors affecting the leakage rate of water distribution system, we built a macroscopic "leakage rate–leakage factors"(LRLF) model. In this model, we consider the pipe attributes(quality, dia... To analyze the factors affecting the leakage rate of water distribution system, we built a macroscopic "leakage rate–leakage factors"(LRLF) model. In this model, we consider the pipe attributes(quality, diameter,age), maintenance cost, valve replacement cost, and annual average pressure. Based on variable selection and principal component analysis results, we extracted three main principle components—the pipe attribute principal component(PAPC), operation management principal component, and water pressure principal component. Of these, we found PAPC to have the most influence. Using principal component regression, we established an LRLF model with no detectable serial correlations. The adjusted R2 and RMSE values of the model were 0.717 and 2.067, respectively.This model represents a potentially useful tool for controlling leakage rate from the macroscopic viewpoint. 展开更多
关键词 Water DISTRIBUTION system LEAKAGE RATE LEAKAGE influencing factor QUANTITATIVE model principal COMPONENT regression
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Principal Component-Discrimination Model and Its Application
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作者 韩天锡 魏雪丽 +1 位作者 蒋淳 张玉琍 《Transactions of Tianjin University》 EI CAS 2004年第4期315-318,共4页
Having researched for many years, seismologists in China presented about 80 earthquake prediction factors which reflected omen information of earthquake. How to concentrate the information that the 80 earthquake predi... Having researched for many years, seismologists in China presented about 80 earthquake prediction factors which reflected omen information of earthquake. How to concentrate the information that the 80 earthquake prediction factors have and how to choose the main factors to predict earthquakes precisely have become one of the topics in seismology. The model of principal component-discrimination consists of principal component analysis, correlation analysis, weighted method of principal factor coefficients and Mahalanobis distance discrimination analysis. This model combines the method of maximization earthquake prediction factor information with the weighted method of principal factor coefficients and correlation analysis to choose earthquake prediction variables, applying Mahalanobis distance discrimination to establishing earthquake prediction discrimination model. This model was applied to analyzing the earthquake data of Northern China area and obtained good prediction results. 展开更多
关键词 principal component analysis discrimination analysis correlation analysis weighted method of principal factor coefficients
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Parallel Active Subspace Decomposition for Tensor Robust Principal Component Analysis
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作者 Michael K.Ng Xue-Zhong Wang 《Communications on Applied Mathematics and Computation》 2021年第2期221-241,共21页
Tensor robust principal component analysis has received a substantial amount of attention in various fields.Most existing methods,normally relying on tensor nuclear norm minimization,need to pay an expensive computati... Tensor robust principal component analysis has received a substantial amount of attention in various fields.Most existing methods,normally relying on tensor nuclear norm minimization,need to pay an expensive computational cost due to multiple singular value decompositions at each iteration.To overcome the drawback,we propose a scalable and efficient method,named parallel active subspace decomposition,which divides the unfolding along each mode of the tensor into a columnwise orthonormal matrix(active subspace)and another small-size matrix in parallel.Such a transformation leads to a nonconvex optimization problem in which the scale of nuclear norm minimization is generally much smaller than that in the original problem.We solve the optimization problem by an alternating direction method of multipliers and show that the iterates can be convergent within the given stopping criterion and the convergent solution is close to the global optimum solution within the prescribed bound.Experimental results are given to demonstrate that the performance of the proposed model is better than the state-of-the-art methods. 展开更多
关键词 principal component analysis Low-rank tensors Nuclear norm minimization Active subspace decomposition Matrix factorization
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Evaluation of Social Perception on Water Issues in Cameron Highlands (Malaysia) by Principle Factor Analysis
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作者 K.W. Tan M.B. Mokhtar 《Journal of Environmental Science and Engineering》 2010年第4期45-52,共8页
Dealing with water resources issues requires understanding of the community perception. It is important to create a communicative partnership between community and government towards sustainable water resources manage... Dealing with water resources issues requires understanding of the community perception. It is important to create a communicative partnership between community and government towards sustainable water resources management. Opinion survey is an essential step to gather the point of view from local community. However, it always generates a large and complex dataset that are difficult to be interpreted by decision maker. In order to overcome this difficulty, statistical methods are applied to develop an interpretability model for decision maker. This study demonstrated the application of Descriptive Analysis and Principle Factor Analysis (PFA) to reduce the complexity of opinion survey dataset by revealing underlying information. A total of 106 respondents were interviewed; consisting of 68 male and 38 female respondents respectively. This study first applied descriptive analysis to identify the basic score for each variable, and these variables are soil erosion (68.9%), degradation of water quality (65.1%), degradation of freshwater ecosystem (61.0%), water shortage (50%), agricultural solid waste problem (46.2%), water borne diseases (23.6%), illegal land clearing (21.7%), legal land clearing (15.1%), uncontrolled river water abstraction in upstream (54.7%)), poor solid waste management (34.0%), low awareness of local community (61.3%), haphazard planning and development (74.5%) and administration mistake (37.0%). Based on the PFA result, a total of four rotated factors were extracted, representing different aspects of water related issues in Cameron Highlands. Factor 1, 2, 3 and 4 were summarised to four topics namely: (1) water environment degradation caused by illegal solid waste disposal and low awareness of community, (2) agricultural development leading to negative impacts on water resources such as water shortage and ecosystem deterioration, (3) land clearing activity leading to serious land erosion (4) human health problem due to e-coli bacterial pollution and administration mistake on land development in Cameron Highlands. 展开更多
关键词 Descriptive analysis principal factor analysis local perception water issues cameron highlands.
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Evolution of Principal Contradiction Facing Chinese Society and the CPC Leadership over Economic Work
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作者 Shi Dan 《China Economist》 2022年第3期2-20,共19页
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
关键词 Centenary of the CPC’s founding principal contradiction economic development success factors
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Type 2 Possibility Factor Rotation in No-Data Problem
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作者 Houju Hori 《Applied Mathematics》 2023年第10期673-683,共11页
Uemura [1] discovered a mapping formula that transforms and maps the state of nature into fuzzy events with a membership function that expresses the degree of attribution. In decision theory in no-data problems, seque... Uemura [1] discovered a mapping formula that transforms and maps the state of nature into fuzzy events with a membership function that expresses the degree of attribution. In decision theory in no-data problems, sequential Bayesian inference is an example of this mapping formula, and Hori et al. [2] made the mapping formula multidimensional, introduced the concept of time, to Markov (decision) processes in fuzzy events under ergodic conditions, and derived stochastic differential equations in fuzzy events, although in reverse. In this paper, we focus on type 2 fuzzy. First, assuming that Type 2 Fuzzy Events are transformed and mapped onto the state of nature by a quadratic mapping formula that simultaneously considers longitudinal and transverse ambiguity, the joint stochastic differential equation representing these two ambiguities can be applied to possibility principal factor analysis if the weights of the equations are orthogonal. This indicates that the type 2 fuzzy is a two-dimensional possibility multivariate error model with longitudinal and transverse directions. Also, when the weights are oblique, it is a general possibility oblique factor analysis. Therefore, an example of type 2 fuzzy system theory is the possibility factor analysis. Furthermore, we show the initial and stopping condition on possibility factor rotation, on the base of possibility theory. 展开更多
关键词 Type 2 Fuzzy Events Quadratic Mapping Formula Stochastic Differential Equation in Fuzzy Event Possibility principal factor Analysis Possibility Oblique factor Analysis Initial and Stopping Condition
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煤炭地下气化的敏感性地质因素探讨 被引量:3
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作者 周泽 易同生 +3 位作者 秦勇 周永峰 汪凌霞 孔维敏 《煤田地质与勘探》 EI CAS CSCD 北大核心 2024年第3期24-36,共13页
相对于地面煤化工装置,煤炭地下气化(UCG)炉体为地质体,地质条件准确认识是推进UCG气化成功的关键前提。为了最大限度避免煤炭地下气化选区选址地质风险,以贵州复杂地质条件为例,系统探讨其煤炭地下气化的敏感性地质因素。通过收集梳理... 相对于地面煤化工装置,煤炭地下气化(UCG)炉体为地质体,地质条件准确认识是推进UCG气化成功的关键前提。为了最大限度避免煤炭地下气化选区选址地质风险,以贵州复杂地质条件为例,系统探讨其煤炭地下气化的敏感性地质因素。通过收集梳理贵州煤炭资源勘查资料,建立归一化的参数分级赋值、参数权重向量算法、参数权重积算法等数学模型,准确获取研究区地质参数量化数据;基于由26个地质因素构成的地质参数集,采用数理统计方法,识别地质风险关键因素对复杂构造区煤层UCG可行性的交叉影响,查明建炉可行性、过程易控性、气化安全性、开发经济性“四性”指标敏感性地质风险源。结果表明:“四性”指标地质参数的敏感性有所差异,建炉可行性、过程易控性、气化安全性、开发经济性的地质因素敏感性依次变弱,UCG可行性对建炉可行性的依赖性最强,过程易控性次之,其他两个条件离散性相对较大,敏感性明显降低;就敏感性程度而言,26项地质参数中最为敏感的是煤的坚固性系数,其他8个主控地质因素分别是煤层厚度、煤层倾角、煤厚变异系数、夹矸厚度系数、断层指数、煤层埋深、奥亚膨胀度和黏结指数,影响建炉可行性、过程易控性两个方面。就贵州UCG敏感性地质因素来说,UCG项目成功与否的关键在于建炉可行性,气化炉选址应优先考虑构造发育特征及其对煤层条件的影响;为持续推进煤炭地下气化产业发展,下一步或可立足于我国煤炭资源特性及赋存条件实际,以“四性”认识为基础建立统一的UCG地质风险评价准则,进而为典型地质条件先导性试验区选址提供科学依据。 展开更多
关键词 无井式 煤炭地下气化 敏感性因素 地质因素 主成分分析 气化炉选址
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生物电化学厌氧消化的应用现状与研究进展
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作者 李蕾 罗思晗 +4 位作者 叶文杰 孙惠 陈颜子云 王小铭 彭绪亚 《中国环境科学》 EI CAS CSCD 北大核心 2024年第5期2568-2579,共12页
调研了近年来报道的生物电化学厌氧消化经典案例,梳理了该系统的构型及工作原理;讨论了其解抑增效潜能及机理;分析了外加电压、电极材料及布置间距等对系统强化效果的影响.目前,生物电化学厌氧消化系统通常可将厌氧消化甲烷产率产量提高... 调研了近年来报道的生物电化学厌氧消化经典案例,梳理了该系统的构型及工作原理;讨论了其解抑增效潜能及机理;分析了外加电压、电极材料及布置间距等对系统强化效果的影响.目前,生物电化学厌氧消化系统通常可将厌氧消化甲烷产率产量提高0.15~8.6倍,提升沼气中的甲烷含量至原来的1.2~1.6倍.外加电极及电压造成的功能微生物富集和电子高效传递是系统性能强化的主要原因.有鉴于此,电压和电极材料是系统效能的主要影响因素.该系统的规模化运行受到经济性制约,后期探索间歇供电、新能源供电、峰谷电等用电策略或形式;研发利于微生物富集但不易结垢的电极材料,创新电极组件摆放或嵌入型式等可能对该系统的工程化应用具有重要促进作用. 展开更多
关键词 生物电化学厌氧消化 技术原理 系统效能 强化机理 影响因素
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旅游交通综合体影响因素及动力机制研究
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作者 杨星 余青 《公路交通科技》 CAS CSCD 北大核心 2024年第5期134-142,共9页
旅游交通综合体属于交通运输与旅游业融合发展进程中的新生事物。为有效推进旅游交通综合体健康、可持续发展,针对目前其概念内涵不清晰、影响因素不明确、发展路径不明朗、建设发展偏盲目等问题,基于节点布局规律,借助交通运输学、旅... 旅游交通综合体属于交通运输与旅游业融合发展进程中的新生事物。为有效推进旅游交通综合体健康、可持续发展,针对目前其概念内涵不清晰、影响因素不明确、发展路径不明朗、建设发展偏盲目等问题,基于节点布局规律,借助交通运输学、旅游学、经济学、系统学等相关理论,提出旅游交通综合体的定义、内涵、主要组成要素及构成原理。借鉴旅游目的地生命周期理论,提出了旅游交通综合体“孕育阶段—快速成长阶段—逐步成熟阶段—稳定阶段—衰退(或重生)阶段”的演进发展过程。遵循“研究基础—理论体系—影响因素—阶段分析—动力机制”的总体思路,从文献分析、实证探索、自身功能特征分析3方面入手,通过专家问卷调查确定旅游交通综合体的2个1级影响因素、12个2级影响因素和37个3级影响因素。依据主成分分析法,遴选确定7个核心影响因素。利用动力机制中“内生动力、外生动力”等相关概念和作用原理,对旅游交通综合体的影响机理和动力机制进行分析。在此基础上,深入剖析5个发展阶段的核心影响因素和辅助影响因素,进而得出旅游交通综合体不同阶段发展演进的影响机理及推动其发展演进的核心动力因素。 展开更多
关键词 交通工程 旅游交通综合体 主成分分析 动力机制 影响因素
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林芝市引进梨品种果实品质的综合分析与评价模型构建
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作者 叶彦辉 王秀 +4 位作者 柳羽 韩艳英 张西哲 陶江 周玉柳 《果树学报》 CAS CSCD 北大核心 2024年第10期2117-2129,共13页
【目的】在西藏引入不同优良梨品种,以调整区内梨果树种植结构,为推动西藏特色林果业发展提供理论依据。【方法】以西藏林芝市引入的9个梨品种作为试验材料,成熟后测定其12项果实品质指标。通过相关性分析和因子分析,建立基于因子分析... 【目的】在西藏引入不同优良梨品种,以调整区内梨果树种植结构,为推动西藏特色林果业发展提供理论依据。【方法】以西藏林芝市引入的9个梨品种作为试验材料,成熟后测定其12项果实品质指标。通过相关性分析和因子分析,建立基于因子分析、主成分分析、线性回归分析以及相似性分析的综合品质评价模型,并根据综合品质得分进行优良度排序,筛选出适宜林芝市种植的优良梨品种。【结果】9个梨品种的果实品质性状变异系数有所不同,其中果形指数的变异系数较大,单果质量、果实硬度、可滴定酸含量、固酸比和石细胞含量的变异系数均中等,果实横径、果实纵径、果心横径、果心比、可溶性固形物和维生素C含量的变异系数均相对较小。对9个梨品种的12项果实品质性状的因子分析,得知前4个公因子的累积方差贡献率达89.120%,其中,第1个公因子的贡献率为37.240%,主要反映果实大小和酸甜口感品质,第2个公因子的贡献率为20.658%,主要反映了梨果实的软硬程度,第3个公因子的贡献率为17.760%,主要反映了果实形状和维生素C含量,第4个公因子的贡献率为13.642%,主要反映了果实可食部分大小和果实糖含量。各品种间存在显著的统计差异(R=0.768,p=0.001),新梨七号与晚秋黄品种显示出最大的差异性。品种间在多维性状上的分布特点表明质量和横径被识别为分类的关键因素。经综合品质评价模型,得出9个梨品种在林芝种植后的果实综合品质得分高低排序为圆黄、华山、翠冠、中梨1号、初夏绿、新梨七号、翠玉、红太阳和晚秋黄。【结论】研究结果对指导西藏自治区内特色梨品种的选育和促进梨产业的可持续发展具有重要意义。 展开更多
关键词 林芝 果实品质 相关性分析 因子分析 主成分分析 相似性分析
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库车坳陷裂缝性致密砂岩储层有效性评价方法
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作者 刘世伟 别康 +4 位作者 王冬冬 倪小威 刘敏 徐思慧 冯加明 《测井技术》 CAS 2024年第5期661-669,共9页
塔里木盆地库车坳陷多成因裂缝发育为储层提供了有效的储集空间和渗流通道,储层基质岩块孔隙小,是典型的裂缝性致密砂岩储层。面对埋藏深、岩性复杂的致密砂岩储层,孔隙度与渗透率低、喉道细、连通性差、非均质强的问题使得储层有效性... 塔里木盆地库车坳陷多成因裂缝发育为储层提供了有效的储集空间和渗流通道,储层基质岩块孔隙小,是典型的裂缝性致密砂岩储层。面对埋藏深、岩性复杂的致密砂岩储层,孔隙度与渗透率低、喉道细、连通性差、非均质强的问题使得储层有效性评价面临不确定性。单井在物性和裂缝定性评价发育相当的情况下,测试产能差别大,迫切需要开展测井评价攻关研究。从孔隙度、裂缝参数、地应力等方面展开分析,对影响裂缝性致密砂岩储层品质的因素进行系统分析总结。选取孔隙度、裂缝孔隙度、裂缝宽度以及裂缝走向与最大水平主应力夹角等参数,利用测试资料刻画砂岩储层品质,通过调整主控因素相关系数对储层质量进行区分,建立储层品质因子,形成一套利用储层品质因子识别储层有效性的方法。该方法在新井解释评价中取得了较好的效果,为后期的解释评价提供技术支撑。 展开更多
关键词 裂缝性致密砂岩 裂缝参数 最大水平主应力 储层品质因子 储层有效性 库车坳陷
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基于改进时间卷积网络与藤Copula的短期风速预测
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作者 黄宇 张宗拾 +2 位作者 刘家兴 李旭昕 张鹏 《电力科学与工程》 2024年第7期60-69,共10页
考虑风电场相邻风机风速间以及风速与气象因素间复杂的非线性关系,提出了一种基于改进时间卷积网络与藤Copula相结合的风速预测方法。首先,利用深度残差收缩网络中存在的注意力机制及软阈值化的思想改进时间卷积网络中的残差模块,并进... 考虑风电场相邻风机风速间以及风速与气象因素间复杂的非线性关系,提出了一种基于改进时间卷积网络与藤Copula相结合的风速预测方法。首先,利用深度残差收缩网络中存在的注意力机制及软阈值化的思想改进时间卷积网络中的残差模块,并进行初步风速预测;然后,考虑到众多气象因素对风速的影响,使用核主成分分析对气象数据进行降维,在保证数据特征的同时,降低数据的复杂度;最后,利用藤Copula在描述非线性相关结构方面的优势构建修正模型,使用降维的气象数据修正初步风速预测值,得到最终的风速预测结果。实验证明,所提方法提高了短期风速预测的精度。 展开更多
关键词 风速预测 改进时间卷积网络 气象因素 核主成分分析 藤Copula
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多元统计分析在高校学生食品安全学成绩评价中的应用研究
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作者 田晓静 刘根娣 +2 位作者 陆会宁 冯哲 李雪 《西北民族大学学报(自然科学版)》 2024年第3期74-79,共6页
为了解学生的学习状况,选择食品专业必修课食品安全学课程为研究对象,以3届共233名学生食品安全学成绩作为实际数据,对其进行主成分分析、判别分析、相关分析和聚类分析等多元统计分析,以便为教师和学生提供有用信息,更好地改进教学评... 为了解学生的学习状况,选择食品专业必修课食品安全学课程为研究对象,以3届共233名学生食品安全学成绩作为实际数据,对其进行主成分分析、判别分析、相关分析和聚类分析等多元统计分析,以便为教师和学生提供有用信息,更好地改进教学评价方式,提高教学质量. 展开更多
关键词 学生成绩 因子分析 聚类分析 主成分分析 相关分析 评价
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湖北省粮食产量影响因素分析─基于主成分回归
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作者 舒服华 《陕西国防职教研究》 2024年第3期15-19,共5页
由于湖北省粮食播种面积、高标准农田数量、耕地有效灌溉面积、农业生产机械化率数据之间存在多重共线性,分析其对湖北省粮食产量影响时,运用最小二乘法估计参数容易失真而缺乏解释性。因此,利用能够解决多重共线性问题的主成分回归来... 由于湖北省粮食播种面积、高标准农田数量、耕地有效灌溉面积、农业生产机械化率数据之间存在多重共线性,分析其对湖北省粮食产量影响时,运用最小二乘法估计参数容易失真而缺乏解释性。因此,利用能够解决多重共线性问题的主成分回归来分析粮食播种面积、高标准农田数量、耕地有效灌溉面积、农业生产机械化率对湖北省粮食产量影响。回归的参数客观可靠,真实有效,通过对解释变量的释读,结果发现与湖北省粮食生产的实现情况基本吻合。 展开更多
关键词 湖北 粮食产量 影响因素 共线性 主成分回归
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