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Analysis of the Production and Operation Status of Silkworm Eggs Producing Farms in China——Based on Questionnaire Survey to 136 Silkworm Eggs Producing Farms Nationwide
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作者 Li Jianqin Gu Guoda Feng Huaisong 《Animal Husbandry and Feed Science》 CAS 2014年第2期37-45,共9页
Through statistical analysis on questionnaire survey data from 136 silkworm eggs producing farms in China,it was concluded that most silkworm eggs producing farms had such problems as follows: old production facilitie... Through statistical analysis on questionnaire survey data from 136 silkworm eggs producing farms in China,it was concluded that most silkworm eggs producing farms had such problems as follows: old production facilities and poor production condition,heavy staff burden,weak scientific and technological support,small operation scale and heavy surplus production capacity; narrow silkworm eggs sale channels and stubborn regional segmentation,insufficient innovation and lack of technological support for diversified expansion. All these problems led to low labor productivity,low asset utilization rate and poor economic benefit in silkworm eggs producing farms in China. Except the provinces( regions) of Guangxi,Guangdong and Yunnan,the silkworm eggs producing farms in other provinces were generally at deficit condition. In the light of ownership,although silkworm eggs producing farms of different ownership systems were in the red,those of the private sector had the minimum deficit. Based on these findings,it is proposed to deepen system reformation of silkworm eggs producing farms,loosen control to price and circulation of silkworm eggs,implement large-scaled production and operation,speed up scientific and technological innovation,expand diversified development channels,and reinforce government support so as to increase production and operation benefits of silkworm eggs producing farms in China. 展开更多
关键词 Silkworm eggs producing farms Silkworm eggs production Operation BENEFIT ownership
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Theoretical Reflection on Meaning Production of Media Discourse in Intercultural Communications
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作者 Zhang Li Wen Yi 《Contemporary Social Sciences》 2018年第1期29-37,共9页
Media discourse in the context of intercultural communications is an important channel that countries and cultures use to communicate. It is also a process of meaning interpretation and knowledge production, which exe... Media discourse in the context of intercultural communications is an important channel that countries and cultures use to communicate. It is also a process of meaning interpretation and knowledge production, which exerts a great impact on the establishment of the world's cultural order. This paper discusses media discourse in intercultural communications theoretically from the perspective of knowledge production, media dialogue and meaning construction. It is suggested that an effective ideographic mechanism be developed and improved, and the essential meaning of Chinese culture be initiatively exported and integrated into a knowledge system of cognition and understanding about the world to promote the understanding and exchange between China and other countries and to help create an equal and reasonable world cultural order. 展开更多
关键词 media discourse meaning construction knowledge production DIALOGUE
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Properties of collective flow and pion production in intermediate-energy heavy-ion collisions with a relativistic quantum molecular dynamics model
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作者 Si-Na Wei Zhao-Qing Feng 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第1期155-169,共15页
The relativistic mean-field approach was implemented in the Lanzhou quantum molecular dynamics transport model(LQMD.RMF). Using the LQMD.RMF, the properties of collective flow and pion production were investigated sys... The relativistic mean-field approach was implemented in the Lanzhou quantum molecular dynamics transport model(LQMD.RMF). Using the LQMD.RMF, the properties of collective flow and pion production were investigated systematically for nuclear reactions with various isospin asymmetries. The directed and elliptic flows of the LQMD.RMF are able to describe the experimental data of STAR Collaboration. The directed flow difference between free neutrons and protons was associated with the stiffness of the symmetry energy, that is, a softer symmetry energy led to a larger flow difference. For various collision energies, the ratio between the π^(-) and π^(+) yields increased with a decrease in the slope parameter of the symmetry energy. When the collision energy was 270 MeV/nucleon, the single ratio of the pion transverse momentum spectra also increased with decreasing slope parameter of the symmetry energy in both nearly symmetric and neutron-rich systems.However, it is difficult to constrain the stiffness of the symmetry energy with the double ratio because of the lack of threshold energy correction on the pion production. 展开更多
关键词 Heavy-ion collision Collective flow Pion production Symmetry energy Relativistic mean field
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Spatial and temporal relationships between precipitation and ANPP of four types of grasslands in northern China 被引量:17
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作者 GUO Ran WANG Xlao-ke +1 位作者 OUYANG Zhi-yun LI Ying-nian 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2006年第5期1024-1030,共7页
Precipitation is considered to be the primary resource limiting terrestrial biological activity in water-limited regions. Its overriding effect on the production of grassland is complex. In this paper, field data of 4... Precipitation is considered to be the primary resource limiting terrestrial biological activity in water-limited regions. Its overriding effect on the production of grassland is complex. In this paper, field data of 48 sites (including temperate meadow steppe, temperate steppe, temperate desert steppe and alpine meadow) were gathered from 31 published papers and monographs to analyze the relationship between above-ground net primary productivity (ANPP) and precipitation by the method of regression analysis. The results indicated that there was a great difference between spatial pattern and temporal pattern by which precipitation influenced grassland ANPP. Mean annual precipitation (MAP) was the main factor determining spatial distribution of grassland ANPP (r^2 = 0.61, P 〈 0.01); while temporally, no significant relationship was found between the variance of AN PP and inter-annual precipitation for the four types of grassland. However, after dividing annual preeipitation into monthly value and taking time lag effect into account, the study found significant relationships between ANPP and precipitation. For the temperate meadow steppe, the key variable determining inter-annual change of ANPP was last August-May precipitation (r^2 = 0.47, P = 0.01); for the temperate steppe, the key variable was July precipitation (r^2 = 0.36, P = 0.02); for the temperate desert steppe, the key variable was April-June precipitation (r^2 = 0.51, P 〈 0.01); for the alpine meadow, the key variable was last September-May precipitation (r^2 = 0.29, P 〈 0.05). In comparison with analogous research, the study demonstrated that the key factor determining inter-annual changes of grassland ANPP was the cumulative precipitation in certain periods of that year or the previous year. 展开更多
关键词 above-ground net primary productivity mean annual precipitation spatial sensitivity inter-annual changes
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As Could We Assure Safety in Large-Scale Manufacturing of Nanoparticles for the Biomedical Use
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作者 Kirill Serguey Maksimov Serguei Kirillovich Maksimov Nikolay Dmitrievich Soukhov 《Journal of Biomaterials and Nanobiotechnology》 2011年第5期601-613,共13页
Nanoparticles provide great advantages but also great risks. Risks associating with nanoparticles are the problem of all technologies, but they increase in many times in nanotechnologies. Adequate methods of outgoing ... Nanoparticles provide great advantages but also great risks. Risks associating with nanoparticles are the problem of all technologies, but they increase in many times in nanotechnologies. Adequate methods of outgoing production inspection are necessary to solve the problem of risks, and the inspection must be based on the safety standard. Existing safety standard results from a principle of “maximum permissible concentrations or MPC”. This principle is not applicable to nanoparticles, but a safety standard reflecting risks inherent in nanoparticles doesn’t exist. Essence of the risks is illustrated by the example from pharmacology, since its safety assurance is conceptually based on MPC and it has already come against this problem. Possible formula of safety standard for nanoparticles is reflected in many publications, but conventional inspection methods cannot provide its realization, and this gap is an obstacle to assumption of similar formulas. Therefore the development of nanoparticle industry as a whole (also development of the pharmacology in particular) is impossible without the creation of an adequate inspection method. There are suggested new inspection methods founded on the new physical principle and satisfying to the adequate safety standard for nanoparticles. These methods demonstrate that creation of the adequate safety standard and the outgoing production inspection in a large-scale manufacturing of nanoparticles are the solvable problems. However there is a great distance between the physical principle and its hardware realization, and a transition from the principle to the hardware demands great intellectual and material costs. Therefore it is desirable to call attention of the public at large to the necessity of urgent expansions of investigations associated with outgoing inspections in nanoparticles technologies. It is necessary also to attract attention, first, of representatives of state structures controlling approvals of the adequate safety standard to this problem, since it is impossible to compel producers providing the safety without the similar standard, and, second, of leaders of pharmacological industry, since their industry already entered into the nanotechnology era, and they have taken an interest in a forthcoming development of inspection methods. 展开更多
关键词 Risks of NANOPARTICLE LARGE-SCALE MANUFACTURING Adequate SAFETY Standard Outgoing production Inspection Structure and HABIT Scanning ELECTRON Microscopy HABIT Control by means of Convergent Illuminating ELECTRON Beams SAFETY Assurance in the NANOPARTICLE Industry Is a Solvable Problem
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Production of Meaning--A Critical Study of Narrative Ethics in Joyce Carol Oates's New Century Fiction
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作者 Liu Xiaoyan 《疯狂英语(理论版)》 2018年第2期178-181,190,共5页
Narrative ethics shows multiple representing methods in Oates' s novels,including not only a variety of characters' narrative construction processes of self-narrative,other-narrative and social narrative but a... Narrative ethics shows multiple representing methods in Oates' s novels,including not only a variety of characters' narrative construction processes of self-narrative,other-narrative and social narrative but also the meaninggenerating process of the characters' interpretation and reorganization of the external and internal world.In so doing,the characters are able to obtain personal identity,the ethical communication and existence transcendence by the way of narrative. 展开更多
关键词 Joyce Carol Oates narrative ethics production of meaning
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Exploiting Virtual Elasticity of Production Systems to Respect OTD—Part 3: Basic Considerations for Modelling CPPS Characterized by Non-Ergodic Order Entry and Non-Deterministic Product-Mix for Fully Flexible Addressable Workstations
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作者 Bruno G. Rüttimann Martin T. Stöckli 《American Journal of Operations Research》 2022年第2期19-63,共45页
The recently experienced hype concerning the so-called “4<sup>th</sup> Industrial Revolution” of production systems has prompted several papers of various subtopics regarding Cyber-Phdysical Production S... The recently experienced hype concerning the so-called “4<sup>th</sup> Industrial Revolution” of production systems has prompted several papers of various subtopics regarding Cyber-Phdysical Production Systems (CPPS). However, important aspects such as the modelling of CPPS to understand the theory regarding the performance of highly non-ergodic and non-deterministic flexible manufacturing systems in terms of Exit Rate (ER), Manufacturing Lead Time (MLT), and On-Time Delivery (OTD) have not yet been examined systematically and even less modeled analytically. To develop the topic, in this paper, the prerequisites for modelling such systems are defined in order to be able to derive an explicit and dedicated production mathematics-based understanding of CPPS and its dynamics: switching from explorative simulation to rational modelling of the manufacturing “physics” led to an own and specific manufacturing theory. The findings have led to enouncing, among others, the Theorem of Non-Ergodicity as well as the Batch Cycle Time Deviation Function giving important insights to model digital twin-based CPPS for complying with the mandatory OTD. 展开更多
关键词 On-Time-Delivery production System Industry 4.0 CPPS IoT Stochastic Arrival Rate Non-Ergodic Process Virtual Elasticity production Capacity Nominal Mean Exit Rate theorem of Non-Ergodicity Non-Deterministic Product-Mix TFL AGV Scheduling Algorithm Digital Twin
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Effect of Stem Density on Leaf Nutrient Dynamics and Nutrient Use Efficiency of Dwarf Bamboo 被引量:4
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作者 WU Fu-Zhong YANG Wan-Qin +2 位作者 WANG Kai-Yun WU Ning LU Ye-Jiang 《Pedosphere》 SCIE CAS CSCD 2009年第4期496-504,共9页
The monthly dynamics of nitrogen (N) and phosphorus (P) concentrations and stocks in leaves, resorption efficiency, and resorption proficiency as well as leaf-level use efficiency, nutrient productivity, and mean ... The monthly dynamics of nitrogen (N) and phosphorus (P) concentrations and stocks in leaves, resorption efficiency, and resorption proficiency as well as leaf-level use efficiency, nutrient productivity, and mean residence time were studied to understand the effect of stem density of dwarf bamboo (Fargesia denudata Yi) on leaf-level N and P use efficiency in three dwarf bamboo stands with different stem densities under bamboo-fir (Picea puvpurea Mast.) forest over one growing period in the Wanglang National Nature Reserve, Sichuan, China. Dwarf bamboo density had little effect on the dynamics pattern of both N and P concentrations, stocks, resorption efficiency, and resorption proficiency, but strongly affected their absolute values and leaf-level use efficiency. Higher density stands stored more nutrients but had lower concentrations. There was a clear difference in the resorption of limiting nutrient (N) and non-limiting nutrient (P) among the stands. Phosphorus resorption efficiency, N resorption proficiency, and P resorption proficiency increased with increase of stem density, but no significant variation of N resorption efficiency was found among the stands. Moreover, the higher density stands used both N and P more efficiently with higher N productivity and higher P mean residence time, respectively. Higher P productivity was found in the lower density stands, but there was no clear variation in the N mean residence time among stands. These suggested that the higher density stands may have more efficient strategies for utilizing nutrients, especially those which are limiting . 展开更多
关键词 mean residence time nutrient productivity nutrient resorption
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A Class of Estimators for Population Ratio in Simple Random Sampling Using Variable Transformation 被引量:2
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作者 A. C. Onyeka V. U. Nlebedim C. H. Izunobi 《Open Journal of Statistics》 2014年第4期284-291,共8页
This paper is an extension and generalization of the study carried out by [1] on the estimation of the population ratio (R) of the population means of two variables (y and x) under Simple Random Sampling (SRS) scheme,... This paper is an extension and generalization of the study carried out by [1] on the estimation of the population ratio (R) of the population means of two variables (y and x) under Simple Random Sampling (SRS) scheme, using a variable transformation of the auxiliary variable, x. All the six estimators proposed by [1] are easily identified as special cases of the proposed class of estimators. Asymptotic properties of the proposed class of estimators are derived theoretically and subsequently verified using empirical illustrations. Some of the proposed estimators are found to have relatively large gains in efficiency over the customary ratio estimator, ?for the given data set. 展开更多
关键词 Variable TRANSFORMATION RATIO Product and Regression-Type ESTIMATORS Mean Squared ERROR
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Modeling height growth for teak plantations in Colombia using the reducible stochastic differential equation approach
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作者 Sergio Orrego Cristian Montes +2 位作者 Héctor IRestrepo Bronson PBullock Mauricio Zapata 《Journal of Forestry Research》 SCIE CAS CSCD 2021年第3期1035-1045,共11页
Teak(Tectona grandis L.f.)plantations are increasingly being established in tropical regions to meet a rising demand for its highly valued timber.Teak plantations have been established in the Atlantic Coastal Plain re... Teak(Tectona grandis L.f.)plantations are increasingly being established in tropical regions to meet a rising demand for its highly valued timber.Teak plantations have been established in the Atlantic Coastal Plain region of Colombia,a region climatically suitable for teak growth by having a monsoon climate with a unimodal precipitation pattern.Tree diameter at breast height(DBH,1.3 m above ground)and mean top height,periodically measured over a 17-year period in 44 permanent sampling plots of size 0.06 and 0.10 ha,were used in this study.A stochastic differential equation(SDE),along with a Bertalanffy–Richards-type height growth model,was used to model and estimate top height growth of teak plantations in Colombia.Environmental noise and height measurement errors were explicitly considered as the main uncertainty sources of mean top height growth.The best model for estimating mean top height,based on statistical performance and biological rationale,had the asymptote defined as a local parameter and the growth rate and shape specified as global parameters.This model outperformed its counterpart that had the growth rate specified as a local parameter and asymptote and shape as global parameters.The selected model also outperformed alternative approaches such as the mixed-effects model,generalized algebraic difference approach,and the dummy variable method.Estimated trajectories for the mean top height of teak in Colombia are biologically sound based on the measured height series and previous studies in Latin America.Results suggest that most of the uncertainty associated with the mean top height growth of teak plantations in Colombia was largely explained by environmental noise.The best estimated model using the SDE approach can be useful for predicting height growth and evaluating site productivity of teak plantations in Colombia and in neighbouring countries with biophysical characteristics similar to those where teak has been planted in Colombia. 展开更多
关键词 Mean top height Stochastic differential equation Forest productivity Timber production Timberland investment
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Analytical Solution for Three-dimensional Forging Taking into Account Bulging of Sides by Mean Yield Criterion 被引量:1
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作者 DU Haijun ZHAO Dewen WANG Genji WANG Guodong 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2010年第4期477-483,共7页
Currently, for some complex plastic deformations, the analytical solution can not be obtained by using Mises yield criterion, because Mises yield criterion is nine dimensions, the velocity field is complex, and the so... Currently, for some complex plastic deformations, the analytical solution can not be obtained by using Mises yield criterion, because Mises yield criterion is nine dimensions, the velocity field is complex, and the solving methods are not innovative. Corresponding solutions of these problems are that yield criterion is linearized to reduce the variable numbers, and the velocity field and the solving methods are reasonably simplified, respectively. In this paper, a new linear yield criterion--mean yield(MY) criterion and inner-product of strain rate vector are used to analytically solve 3D forging taking into account bugling of sides. The velocity field is expressed as a vector in three dimensions, and rotation and divergence are applied to confirm that the velocity field is kinematically admissible. Then, the corresponding strain rate tensor of the velocity field is transformed into principal one by making the determinant of coefficients of the tensor cubic equation be zero. By using MY criterion, the plastic power is term by term integrated and summed according to inner-product of strain rate vector. An upper bound analytical solution is obtained for the forging, and verified by a pure lead press test. The test result turns out that the total pressure calculated by MY criterion is higher by 2.5%-15% than measuring value. In addition, a measuring formula of bulging parameter (a) is proposed, but the values of a measured by the formula are lower than those optimized by the golden section search. The total pressure calculated by MY criterion is compared with the ones by twin shear, Trasca yield, and Mises yield criterion. The comparing result shows that the total pressure calculated by MY criterion is slightly higher than the mean value of that by twin shear and Trasca yield criterion, and lower than that by Mises yield criterion, but more close to that by Mises yield criterion compared with that by other two. The proposed analytical solving methods can be effectively used to other complex plastic deformation, simplifying the solving process and obtaining the reasonable results. 展开更多
关键词 mean yield criterion three-dimensional forging BULGING strain rate vector inner-product
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Estimation of Population Ratio in Post-Stratified Sampling Using Variable Transformation
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作者 Aloy Chijioke Onyeka Chinyeaka Hostensia Izunobi Iheanyi Sylvester Iwueze 《Open Journal of Statistics》 2015年第1期1-9,共9页
Extending the work carried out by [1], this paper proposes six combined-type estimators of population ratio of two variables in post-stratified sampling scheme, using variable transformation. Properties of the propose... Extending the work carried out by [1], this paper proposes six combined-type estimators of population ratio of two variables in post-stratified sampling scheme, using variable transformation. Properties of the proposed estimators were obtained up to first order approximations,(on–1), both for achieved sample configurations (conditional argument) and over repeated samples of fixed size n (unconditional argument). Efficiency conditions were obtained. Under these conditions the proposed combined-type estimators would perform better than the associated customary combined-type estimator. Furthermore, optimum estimators among the proposed combined-type estimators were obtained both under the conditional and unconditional arguments. An empirical work confirmed the theoretical results. 展开更多
关键词 Variable TRANSFORMATION Combined-Type ESTIMATOR Ratio Product and Regression-Type ESTIMATORS Mean Squared Error
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A Three-Stage Stochastic Dynamic Pricing Game Model Affected by New Products into the Market
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作者 Waka Cheung Fang Chen 《Open Journal of Statistics》 2015年第4期284-290,共7页
In real-life marketing, a common phenomenon is that the prices of current product will have been cut down even the new product has not gone into market yet. Thus, it is very important for merchant to set the strategy ... In real-life marketing, a common phenomenon is that the prices of current product will have been cut down even the new product has not gone into market yet. Thus, it is very important for merchant to set the strategy which can make the excepted revenue maximum. So, this paper constructs a three-stage stochastic dynamic pricing game model for analyzing the influence of the uncertainty of entry timing of the new products on pricing of products being sold. By analyzing of the pricing strategy, there are big differences in the predictions of new product going into market between merchant and customers;the merchant will adopt cutting price for promotion strategy to reduce negative influence of the new products on the demand of the products sold now. Otherwise, the merchant will adopt the strategy of maximizing current period’s profit. 展开更多
关键词 STOCHASTIC Dynamic PRICING Game Model New Products ENTRY into MARKET Depreciate SALES PROMOTION means
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Using Biophysical Variables and Stand Density to Estimate Growth and Yield of <i>Pinus patula</i>in Antioquia, Colombia
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作者 Héctor I. Restrepo Sergio A. Orrego +2 位作者 Juan C. Salazar-Uribe Bronson P. Bullock Cristian R. Montes 《Open Journal of Forestry》 2019年第3期195-213,共19页
Timberland investment opportunities in Colombia are expected to increase as a result of the peace agreement recently signed between the Colombian government and the Revolutionary Armed Forces of Colombia. This new soc... Timberland investment opportunities in Colombia are expected to increase as a result of the peace agreement recently signed between the Colombian government and the Revolutionary Armed Forces of Colombia. This new socio-political environment may facilitate the expansion of commercial forest plantations on a wider range of site conditions that are currently considered in existing biometric tools. Data from 1119 temporary plots of unthinned, unmanaged, and genetically unimproved Pinus patula plantations in the Antioquia region were combined with a large set of biophysical attributes to identify spatial variation in yield. A wide array of biophysical covariates was explored to characterize the most favorable environmental conditions for the species, and to identify potential explanatory variables to be included in forest yield models. The mathematical form of the model is the von Bertalanffy-Chapman-Richards type, with parameters: asymptote, intrinsic growth rate and allometric constant. The parameters were expressed as linear functions of soil pH, terrain slope, the mean annual temperature to mean annual precipitation ratio, and stand density. The statistical contribution of selected covariates was evaluated using the likelihood ratio test. The model was validated using an independent set of 133 observations. The spatial representation of the model depicts the timber production potential and allows for the identification of the most suitable geographical areas to establish Pinus patula plantations in Antioquia, Colombia. The estimated yield model provides a reliable baseline for timber production, and insight into timberland investments in Colombia. 展开更多
关键词 Von BERTALANFFY Chapman-Richards Fixed-Effect Models Forest Productivity Mexican PINE Mean Annual INCREMENT
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Generalized Class of Mean Estimators with Known Measures for Outliers Treatment
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作者 Ibrahim M.Almanjahie Amer Ibrahim Al-Omari +1 位作者 Emmanuel J.Ekpenyong Mir Subzar 《Computer Systems Science & Engineering》 SCIE EI 2021年第7期1-15,共15页
In estimation theory,the researchers have put their efforts to develop some estimators of population mean which may give more precise results when adopting ordinary least squares(OLS)method or robust regression techni... In estimation theory,the researchers have put their efforts to develop some estimators of population mean which may give more precise results when adopting ordinary least squares(OLS)method or robust regression techniques for estimating regression coefficients.But when the correlation is negative and the outliers are presented,the results can be distorted and the OLS-type estimators may give misleading estimates or highly biased estimates.Hence,this paper mainly focuses on such issues through the use of non-conventional measures of dispersion and a robust estimation method.Precisely,we have proposed generalized estimators by using the ancillary information of non-conventional measures of dispersion(Gini’s mean difference,Downton’s method and probabilityweighted moment)using ordinary least squares and then finally adopting the Huber M-estimation technique on the suggested estimators.The proposed estimators are investigated in the presence of outliers in both situations of negative and positive correlation between study and auxiliary variables.Theoretical comparisons and real data application are provided to show the strength of the proposed generalized estimators.It is found that the proposed generalized Huber-M-type estimators are more efficient than the suggested generalized estimators under the OLS estimation method considered in this study.The new proposed estimators will be useful in the future for data analysis and making decisions. 展开更多
关键词 Product estimators ratio estimators regression estimators ordinary least square Huber M mean squared error EFFICIENCY
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A KERNEL ESTIMATOR OF A DENSITY FUNCTION IN MULTIVARIATE CASE FROM RANDOMLY CENSORED DATA
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作者 周勇 《Acta Mathematica Scientia》 SCIE CSCD 1996年第2期170-180,共11页
A kernel density estimator is proposed when tile data are subject to censorship in multivariate case. The asymptotic normality, strong convergence and asymptotic optimal bandwidth which minimize the mean square error ... A kernel density estimator is proposed when tile data are subject to censorship in multivariate case. The asymptotic normality, strong convergence and asymptotic optimal bandwidth which minimize the mean square error of the estimator are studied. 展开更多
关键词 Kernel density estimator asymptotic normality product-limit estimator mean square error and censored data.
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SPECIAL ISSUE: SPACE PRODUCTION AND URBAN ORDER IN CONTEMPORARY CHINA--The Loss of Urban Order and the Ethical Construction of Urban Order in Contemporary China
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《Social Sciences in China》 2010年第4期120-132,共13页
Rapidly urbanizing China is at a critical period in the construction of urban meaning and order. The city as an organic compound of space represents the organic integration in space of the elements of civilization, wh... Rapidly urbanizing China is at a critical period in the construction of urban meaning and order. The city as an organic compound of space represents the organic integration in space of the elements of civilization, while its meaning provides the ethical ties that link these elements to form an organic whole. A city without a locus of meaning will be buffeted by risks and confrontations. The realization of sustainable urban prosperity requires the integration of the city as an ordered community of meaning at the same time as its physical forms take shape. An important practical path to achieving this aim is restructuring city space in a rational "spatial-ethical ecology" based on integrity and interaction of physical, social and psychological urban space, by means of collective action knitted together by meaning and carried out by communities and organizations. 展开更多
关键词 nature of the city urban meaning urban order space production urban justice
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一种有效的K-means聚类中心初始化方法 被引量:86
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作者 熊忠阳 陈若田 张玉芳 《计算机应用研究》 CSCD 北大核心 2011年第11期4188-4190,共3页
传统K-means算法由于随机选取初始聚类中心,使得聚类结果波动性大;已有的最大最小距离法选取初始聚类中心过于稠密,容易造成聚类冲突现象。针对以上问题,对最大最小距离法进行了改进,提出了最大距离积法。该方法在基于密度概念的基础上... 传统K-means算法由于随机选取初始聚类中心,使得聚类结果波动性大;已有的最大最小距离法选取初始聚类中心过于稠密,容易造成聚类冲突现象。针对以上问题,对最大最小距离法进行了改进,提出了最大距离积法。该方法在基于密度概念的基础上,选取到所有已初始化聚类中心距离乘积最大的高密度点作为当前聚类中心。理论分析与对比实验结果表明,此方法相对于传统K-means算法和最大最小距离法有更快的收敛速度、更高的准确率和更强的稳定性。 展开更多
关键词 K-均值算法 基于密度 初始聚类中心 最大最小距离 最大距离积
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基于密度和聚类指数改进的K-means算法 被引量:10
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作者 毛秀 冒纯丽 丁岳伟 《电子科技》 2015年第11期47-50,64,共5页
传统K-means算法中,随机选择到的初始聚类中心不同会得到不一样的簇类,人工给定的k值与实际聚类数较难达到一致,针对这些问题,文中提出了基于密度和聚类指数改进的K-means聚类算法。根据密度获取高密度集HP,从此集合中选择相互之间距离... 传统K-means算法中,随机选择到的初始聚类中心不同会得到不一样的簇类,人工给定的k值与实际聚类数较难达到一致,针对这些问题,文中提出了基于密度和聚类指数改进的K-means聚类算法。根据密度获取高密度集HP,从此集合中选择相互之间距离最大的两对对象均值当成第一轮聚类的聚类中心,新的聚类中心可通过最大距离积法获取,并参考聚类指数确定合适的k值。通过进行实验确认了该算法有较高的准确性和有效性。 展开更多
关键词 K-均值算法 初始聚类中心 高密度集 最大距离积法 聚类指数
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基于均值与最大距离乘积的初始聚类中心优化K-means算法 被引量:17
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作者 段桂芹 《计算机与数字工程》 2015年第3期379-382,共4页
针对K-means算法随机选择初始聚类中心所出现的样本聚类结果随机性强、稳定性低、容易陷入局部最优和得不到全局最优解等问题,提出一种基于均值与最大距离乘积的初始聚类中心优化K-means算法。该算法首先选择距离样本集均值最远的数据... 针对K-means算法随机选择初始聚类中心所出现的样本聚类结果随机性强、稳定性低、容易陷入局部最优和得不到全局最优解等问题,提出一种基于均值与最大距离乘积的初始聚类中心优化K-means算法。该算法首先选择距离样本集均值最远的数据对象加入聚类中心集合,再依次将与样本集均值和当前聚类中心乘积最大的数据对象加入聚类中心集合。标准数据集上的实验结果表明,与原始K-means的算法以及另一种改进算法相比,新提出的聚类算法具有更高的准确率。 展开更多
关键词 K-means聚类算法 均值 最大距离乘积 数据挖掘
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