基于大数据分析的海岛旅游目的地形象维度分异研究——以广东阳江“海陵岛”为例

本文选取广东省阳江海陵岛(5A级景区)为案例地,以携程、途牛、马蜂窝、去哪儿等OTA平台用户的在线评论和游记资料为研究数据,运用网络大数据文本分析法,对海岛旅游目的地形象维度分异进行研究。研究结果表明:海陵岛旅游目的地形象感知维度共分为四个层次,其中旅游吸引物和旅游环境分列前两层次,地方氛围、休闲和娱乐、旅游基础设施是第三层次,而公共基础设施属于第四层次;海陵岛的认知形象主要来源于旅游吸引物感知维度;游客对海陵岛旅游形象的认可度较高,其整体形象主要来源于旅游吸引物和休闲娱乐两个目的地感知维度,反映出感知维度的重要程度存在一定的差异性。

基于城市记忆的文化旅游地游后感知维度分异——以南京夫子庙秦淮风光带为例

基于城市记忆的视角,文章选取南京夫子庙秦淮风光带作为典型个案,通过问卷调查和深度访谈,采用数理统计和结构方程模型,实证分析文化旅游地游后感知维度分异特征和机理。结果表明:主客双方对物质要素的游后感知维度呈现相似性递减特征,究其原因,城市化进程中的现代元素有机融入、建筑景观的价值弥足珍贵、自我"造血"和外来"补给"功能的匮乏以及单一静态的陈列展示方式都是其主导因素。但是,对非物质要素的游后感知维度存在层级差异,而非遗传承载体和方式的弱化、地方传统美食颇具特色、经济利益驱动下的文化涵化进程加快以及街巷生活环境遭受"挤压"和"形变"都是其主导诱因。尊重历史,传承记忆,文化旅游地的城市记忆功能保护和传承,任重而道远。

基于网络文本分析的航空小镇旅游形象维度分异研究

以浙江省建德航空小镇为案例地,运用网络爬虫技术法和文本挖掘法,收集了携程网、去哪儿网和马蜂窝网站上401条评论和游记文本,并对文本数据进行高词频统计、社会语义网络分析和情感测度,探究了该小镇的旅游形象感知和维度分异.由此得出结论:第一,建德航空小镇的旅游形象维度具有差异性,其中旅游吸引物维度是第一层次,旅游基础设施维度是第二层次,休闲和娱乐、旅游环境和地方氛围维度是第三层次,公共基础设施维度是第四层次.第二,游客对建德航空小镇的整体感知形象是人文类新兴特色旅游地,认知成分主要由航空文化、特色小镇、休闲娱乐、旅游基础设施4个主题组成.第三,在建德航空小镇旅游形象感知中,积极情感占比大.游客满意度高,说明该小镇正面旅游形象的打造已卓有成效,形成了网络口碑效应.

基于双因子模型的测验总分和维度分的合成方法

双因子模型可以同时包含一个全局因子和多个局部因子,在描述多维测验结构时有其独特优势,近些年应用越来越广泛。文章基于双因子模型,提出了4种合成总分和维度分的方法,分别是:原始分法,加和法,全局题目加权加和法和局部题目加权加和法,并采用模拟的方法,在样本量、测验长度、维度间相关变化的条件下考察了这些方法与传统多维IRT方法的表现。最后,通过实证研究对结果进行了验证。结果显示:(1)全局加权加和法和局部加权加和法,尤其是局部加权加和法合成的总分和维度分与真值最接近、信度最高。(2)在维度间相关较高,测验长度较长的条件下,局部加权加和法的结果较好,部分条件下甚至优于多维IRT法。(3)仅有局部加权加和法合成的维度分能够反应维度间真实的相关关系。

创业导向、组织学习对核心能力及组织绩效的影响研究——来自华中、华南、华北地区210个企业的实证

在日益复杂多变的环境中,企业越来越多地采取创业导向的战略模式,并以组织学习为工具来提升核心能力和组织绩效。用结构方程模型检验理论假设,结果表明,企业的创业导向对组织学习有显著的促进作用,组织的学习可以提升组织的核心能力,核心能力的提升能显著改善组织绩效。组织学习不会直接改善组织绩效,而以核心能力为中介来达到改善组织绩效的目的。企业创业导向对核心能力的影响因产业而不同,对组织绩效的影响因企业生命周期而不同。

Fractal dimension for porous metal materials of FeCrAl fiber

The FeCrA1 fiber was used to prepare porous metal materials with air-laid technology, and then followed by sintering at 1300 ℃ for a holding period of 2 h in the vacuum. In addition, a novel fractal soft, which was developed based on the fractal theory and the computer image processing technology, was explored to describe the pore structure of porous metal materials. Furthermore, the fractal dimension of pore structure was calculated by the soft and the effects of magnification and porosity on ffactal dimension were also discussed. The results show that the fractal dimension decreases with increase in the magnification, while it increases continuously with the porosity enhancing. The interrelationship between the fractal dimension and the magnification or porosity can be presented by the equation of D=α_0exp（-x/α_1）＋α_2和D=k_2-（k_1-k_2）/[1＋exp（（θ-k_0）/k_3）], respectively.

Analysis and identification of SCAR molecular markers associated with birch fiber length trait

The fiber length trait （FLT） of 538 individuals from nature birch population in Maorshan region, Heilongjang, China were measured, of which 100 individuals were selected as representative variety of correlated fragments screening with random amplified polymorphism DNA （RAPD） technique. In total of 20 RAPD primers were tested through multiple regression analysis between amplified strip and the character behaviors, and a correlative segment BFLR-16 was obtained. The correlation coefficient between BFLI-16 and FLT was 0.6144, with the significant level of 1%. BFLI-16 was then cloned, sequenced and transformed into SCAR marker. The percentage of identifying long fiber birches by this SCAR was more than 92. The result indicates that the SCAR markers has high specificity for the long fiber individuals and is highly linked with the gene controlling the character of fiber length, and its existence is significantly correlative with the increase in the fiber length.

A Family of High_order Accuracy Explicit Difference Schemes for Solving 2-D Parabolic Partial Differential Equation

A family of high_order accuracy explicit difference schemes for solving 2_dimension parabolic P.D.E. are constructed. Th e stability condition is r=Δt/Δx 2=Δt/Δy 2【1/2 and the truncation err or is O(Δt 3+Δx 4).

Empirical Bayes Estimation for the Parameter of Two-dimen sional One-side Truncated Distribution Families with Linex Loss

In this paper, we construct the EB estim ation for the parameter of the two-dimensional one side truncat ed distribution fam ilies using Linex loss. The convergence rate of EB estimation is given and it is shown that the proposed empirical Bayes estimaiton can be arbitrarily close to 1 under certain conditions.

Textural and Geochemical Characteristics of Proglacial Sediments: A Case Study in the Foreland of the Nelson Ice Cap, Antarctica

This paper presents a detailed study on the textural and geochemical characteristics of the proglacial sediments near the edge of modern Nelson Ice Cap, Antarctica. The grain size distributions of the proglacial sediments are characteristic of glacigenic deposits, but very different from those of aeolian and lacustrine sediments. Moreover, the grain size distributions of the proglacial sediments are fractal with a dimension of about 2.9, and the fractal dimensions can be used as another summary statistical parameter for quantifying the relative amounts of coarse and fine materials. Correlations between the absolute element abundances of the proglacial sediments are very weak due to mineral partitioning and other effects of glacial processes, but correlations between the element/Rb ratios are statistically significant. This finding indicates that element/Rb ratios can be used to reduce or eliminate the effects of glacial processes, evaluate geochemical data and determine the sediment provenance in the foreland of Antarctic glacier. Comparisons on the element concentrations among different environments suggest that the proglacial sediments are derived predominantly from local bedrocks and appear to be natural in origin. Thus these natural sediments can be used to study chemical weathering in the proglacial foreland of modern glacier.

A numerical simulation of seepage structure surface and its feasibility

According to Cubic law and incompressible fluid law of mass conservation, the seepage character of the fracture surface was simulated with the simulation method of fractal theory and random Brown function. Furthermore, the permeability coefficient of the single fracture was obtained. In order to test the stability of the method, 500 simulations were conducted on each different fractal dimension. The simulated permeability coefficient was analyzed in probability density distribution and probability cumulative distribution statistics. Statistics showed that the discrete degree of the permeability coefficient increases with the increase of the fractal dimension. And the calculation result has better stability when the fractal dimension value is relatively small. According to the Bayes theory, the characteristic index of the permeability coefficient on fractal dimension P（Dfi｜ Ri） is established. The index, P（Dfi｜ Ri）, shows that when the simulated permeability coefficient is relatively large, it can clearly represent the fractal dimension of the structure surface, the probability is 82%. The calculated results of the characteristic index verify the feasibility of the method.

On the Continuity of Julia Sets and Hausdorff Dimension of N CP and Parabolic Maps

Denote by HD（J（f）） the Hausdorff dimension of the Julia set J（f） of a rational function f. Our first result asserts that if f is an NCP map, and fn → f horocyclically,preserving sub-critical relations, then fn is an NCP map for all n ≥≥ 0 and J（fn） →J（f） in the Hausdorff topology. We also prove that if f is a parabolic map and fn is an NCP map for all n ≥≥ 0 such that fn→4 f horocyclically, then J（fn） → J（f） in the Hausdorff topology, and HD（J（fn）） →4 HD（J（f））.

Characterizations of PSD Fractal of Porous Medium

A volume-based method for measuring particle-size distribution (PSD) fractal dimensions of porous mediums was developed by employing laser size-analyzing technology. Compared with conventional approaches of using hydrometer or screen to determine PSD, this method can avoid calculation errors and measure smaller size-scale porous medium. In this paper the experimental porous mediums were brown soil, kaolin and sand soil. A micro-order of magnitude (10 -5 m) in particle-size interval could be shown in PSD results of brown soil and kaolin. The experiments indicated that brown soil had a nearly mono-fractal PSD character, while kaolin and sand soil showed multi-fractal PSD characters. By the adsorption isotherm experiments, the PSD fractal dimensions of the sand soil were also found to keep a linearly increasing relation with the linear adsorptive parameters of the soils in different intervals to adsorb benzene from aqueous solution.

Spatio-temporal distribution of earthquake occurrence in Eastern Himalaya and vicinity(26°N-31°N and 87°E-98°E)based on b-value and fractal dimension

This study investigates the spatial and temporal variation of fractal dimension and b-value for the eastern part of the Himalaya and adjoining area(26°N–31°N and 87°E–98°E).The analysis is carried out on the earthquake dataset of 1373 events(Mc=4.0)by sliding window technique for the period 1964 to 2020.The region is divided into three sub regions A(87°E–92°E),B(92°E–94°E)and C(94°E–98°E).The b-value computed for the region A comprising eastern Nepal is smaller compared to other two regions which infers the possible high stress and asperities in the region.High spatial fractal dimension(Dc>1.5)and low temporal fractal dimension(Dt<0.31)are computed for the regions.High spatial fractal dimension may indicate that fractures generating earthquakes are approaching a 2D structure and low temporal fractal dimension implies high clustering of earthquake’s epicenters.The b value shows a weak negative correlation with Dc for regions A and C while a weak positive correlation is observed for the region B.Based on b-value and fractal dimension,this study explains the frequency of earthquakes and heterogeneity of the seismogenic structure in this part of the Himalaya.

Metrics analysis of tactile perceptual space based on improved NMDS for leather textures

To solve the fuzzy and unstable tactile similarity relationship between some sample points in the perception experiment,an improved non-metric multidimensional scaling(INMDS)is proposed in this paper.In view of the inconsistency of each sample s contribution,the maximum marginal decision when constructing the perception space to describe the tactile perception characteristics is also proposed.The corresponding constraints are set according to the degree of similarity,and controlling the relaxation variable factor is proposed to optimize the perception dimension and coordinate measurement.The effectiveness of the INMDS algorithm is verified by two perception experiments.The results show that compared with the metric multidimensional scaling(MDS)and non-metric multidimensional scaling(NMDS)algorithms,the perceptual space constructed by INMDS can more accurately reflect the difference relationship between different leather sample points perceived by people.Moreover,the relative position of sample points in the perceptual space is more consistent with subjective perception results.

Predictive value of red cell distribution width on left atrial thrombus or left atrial spontaneous echo contrast in patients with non-valvular atrial fibrillation

Objective To evaluate the predictive value of red cell distribution width （RDW） on left atrial thrombus （LAT） or left atrial spontane- ous echo contrast （LASEC） in patients with non-valvular atrial fibrillation （AF）. Methods We reviewed 692 patients who were diagnosed as non-valvular AF and underwent transesophageal echocardiography （TEE） in Guangdong Cardiovascular Institute from April 2014 to December 2015. The baseline clinical characteristics, laboratory test of blood routine, electrocardiograph measurements were analyzed. Results Eighty-four patients were examined with LAT/LASEC under TEE. The mean RDW level was significantly higher in LAT/LASEC patients compared with the non-LAT/LASEC patients （13.59% ± 1.07% ws. 14.34% ± 1.34%; P 〈 0.001）. Receiver-operating characteristic curve analysis was performed and indicated the best RDW cut point was 13.16%. Furthermore, multivariate logistic regression analysis indicated that RDW level 〉 13.16% could be an independent risk factor for LAT/LASEC in patients with AF. Conclusion Elevated RDW level is associated with the presence of LAT/LASEC and could be with moderate predictive value for LAT/LASEC in patients with non-valvular AF.

Strength Distribution Analysis of Typical Staple Fibers

The strength of staple fiber is an important property for yams and fabrics. Usually there are variations in individual fiber strength, and this will affect the finai strength of yarns and fabrics. In this study, Weibuli distribution function is used to analyze the strength distribution of various staple fibers. The strengths of wool, silk, cotton, flax, acrylic, polyester, glass, aramid and carbon fiber are tested. It is found that the strengths of cotton, polyester, glass, aramid and carbon fiber fit well with the two-factor Weibull distribution, while those of wool and silk with the three-factor Weibuil distribution. However, the strength distribution of flax cannot be expressed by either two- or three-factor Weibull distribution convincingly.

A High-order Accuracy Explicit Difference Scheme with Branching Stability for Solving Higher-dimensional Heat-conduction Equation

A high-order accuracy explicit difference scheme for solving 4-dimensional heatconduction equation is constructed. The stability condition is r = △t/△x^2 = △t/△y^2 = △t/△z^2 = △t/△w^2 〈 3/8, and the truncation error is O（△t^2 ＋ △x^4）.

Role of the interaction between a gust front and a mesoscale air mass boundary in convection initiation:a case study

The local convection initiation(CI)mechanisms of a convective case that occurred on5 August 2017 in Cangzhou,northern China,were studied using Doppler radar and automatic weather station observational analysis,along with Variational Doppler Radar Analysis System assimilation analysis.During the convective process,a gust front appeared ahead of two existing convective systems,respectively.In the warm and moist environment ahead of the gust fronts in the south,there was a mesoscale air mass boundary.With the process of a gust front moving southward,approaching the mesoscale air mass boundary,the convergence intensified in the area between the gust front and the mesoscale air mass boundary.Finally,the strong convergent updraft exceeded the level of free convection and triggered the new convection.

Structural characterization of coconut tree leaf sheath fiber reinforce-ment

The coconut palm tree leaf sheath fibers were analyzed by FTIR spectral analysis, Chemical, X-ray and thermo gravimetric methods to assess their suitability as reinforcements in the preparation of green composites. The morphology of the untreated and alkali treated fibers was studied by scanning electron microscopic method. The FTIR and chemical analyses indicated lowering of hemi-cellulose content by alkali treatment of the fibers. The X-ray diffraction revealed an increase in crystallinity of the fibers on alkali treatment. The thermal stability of the fibers was found to increase slightly by alkali treatment. The tensile properties of these fibers increased on alkali treatment. The mechanical and other physical properties indicated that these fibers were suitable as reinforcements for making the green composites.