Fast algorithm on string cross pattern matching

Given a set U which is consisted of strings defined on alphabet Σ, string cross pattern matching is to find all the matches between every two strings in U. It is utilized in text processing like removing the duplication of strings. This paper presents a fast string cross pattern matching algorithm based on extracting high frequency strings. Compared with existing algorithms including single-pattern algorithms and multi-pattern matching algorithms, this algorithm is featured by both low time complexity and low space complexity. Because Chinese alphabet is large and the average length of Chinese words is much short, this algorithm is more suitable to process the text written by Chinese, especially when the size of Σ is large and the number of strings is far more than the maximum length of strings of set U.

Pattern formation induced by cross-diffusion in a predator-prey system

This paper considers the Holling-Tanner model for predator-prey with self and cross-diffusion. From the Turing theory, it is believed that there is no Turing pattern formation for the equal self-diffusion coefficients. However, combined with cross-diffusion, it shows that the system will exhibit spotted pattern by both mathematical analysis and numerical simulations. Furthermore, asynchrony of the predator and the prey in the space. The obtained results show that cross-diffusion plays an important role on the pattern formation of the predator-prey system.

The Effect of Sudden Change in Pipe Diameter on Flow Patterns of Air-Water Two-Phase Flow in Vertical Pipe (Ⅱ) Sudden-Expansion Cross-Section

In this companion paper, flow patterns in the upstream and downstream tubes of a sudden-expansion cross-section (SECS) in a vertical straight pipe were presented. The effect of SECS on flow patterns upstream and downstream was analyzed by comparing with flow patterns in uniform cross-section vertical tubes. It is found the effect is great. There exist great instabilities of two-phase flow in the neighboring areas of the SECS both downstream and upstream.

The Effect of Sudden Change in Pipe Diameter on Flow Patterns of Air-Water Two-Phase Flow in Vertical Pipe (I) Sudden-Contraction Cross-Section

Flow patterns upstream and downstream of a sudden-contraction cross-section in a vertical straight pipe were presented. By comparing with flow patterns in uniform cross-section vertical tubes, the effect of the sudden change in pipe diameter on flow patterns was analyzed. Flow pattern transition mechanisms were discussed and transition criteria for flow pattern transitions were deduced accordingly using the dimensional analysis.

Spatial Pattern Induced by Cross-Diffusion in a Chemostat Model with Maintenance Energy

A chemostat model with maintenance energy and crossdiffusion is considered,and the formation of patterns is caused by the cross-diffusion. First, through linear stability analysis, the necessary conditions for the formation of the spatial patterns are given. Then numerical simulations by changing the values of crossdiffusions in the unstable domain are performed. The results showthat the cross-diffusion coefficient plays an important role in the formation of the pattern, and the different values of the crossdiffusion coefficients may lead to different types of pattern formation.

Pattern selection in a predation model with self and cross diffusion

In this paper, we present the amplitude equations for the excited modes in a cross-diffusive predator-prey model with zero-flux boundary conditions. From these equations, the stability of patterns towards uniform and inhomogenous perturbations is determined. Furthermore, we present novel numerical evidence of six typical turing patterns, and find that the model dynamics exhibits complex pattern replications： for μ1 〈μ ≤μ2, the steady state is the only stable solution of the model; for μ2 〈 μ ≤ μ4, by increasing the control parameter μ, the sequence Hπ-hexagons→ Hπ- hexagon-stripe mixtures → stripes → H0-hexagon-stripe mixtures → H0-hexagons is observed; for μ 〉 μ4, the stripe pattern emerges. This may enrich the pattern formation in the cross-diffusive predatorprey model.

Turing Instability and Pattern Induced by Cross-Diffusion for a Nonlinear Reaction-Diffusion System of Turbulence-Shear Flow Interaction

The Turing instability and the phenomena of pattern formation for a nonlinear reaction-diffusion(RD) system of turbulence-shear flowinteraction are investigated.By the linear stability analysis,the essential conditions for Turing instability are obtained.It indicates that the emergence of cross-diffusion terms leads to the destabilizing mechanism.Then the amplitude equations and the asymptotic solutions of the model closed to the onset of instability are derived by using the weakly nonlinear analysis.

Flow patterns and their transition characteristics of the air-water two-phase flow in a horizontal pipe with a sudden-changed cross-section area

Flow patterns in upstream and downstream straight tubes of sudden-changed areas in a horizontal straight pipe were experimentally examined. Both sudden-expansion cross-section (SECS) and sudden-contraction cross-section (SCCS) were investigated. The flow pattern maps upstream and downstream were delineated and compared with those in straight tubes with uniform cross-sections. The effects of the SECS and SCCS on flow patterns were discussed and analyzed. Furthermore, flow pattern transition mechanisms resulting in occurrences of different flow patterns were simply discussed and some transition criteria for the flow pattern transitions were deduced by using the non-dimensionlized analysis method.

Experimental Study on the Attenuation Law of Vibration Wave Propagation in Natural Gas Wells in Coal-Gas Cross-Mining Area

Aiming at the safety distance between coal mining working face and natural gas wells in the cross-mining area of multiple mineral resources, the cross- mining area of gas and coal resources in the Ordos Basin is taken as the engineering background. An anti-collision early warning technology method based on vibration wave propagation attenuation monitoring is proposed to prevent collision accidents between road headers and natural gas wells. Through the steel pipe and steel pipe concrete knocking vibration test and underground digging vibration test, the research results show that: The exponential decay coefficients of the vibration wave in steel pipe, steel pipe concrete and coal rock respectively are 0.1, 0.1140 and 0.03, which are all in accordance with the exponential decay law, and the vibration wave firstly decays sharply and then decays slowly;the formula for the distance from the road header to the natural gas well was derived based on the vibration attenuation formula, to provide a new method for realizing the problem of precise and coordinated extraction by surface monitoring of the distance from down hole road headers to gas wells, collision prevention prediction and warning and prevention of collision of extraction equipment with gas wells.

Lung Function Impairment among Gasoline Attendants: A Cross-Sectional Study

Background: Occupational health is an important consideration, especially for people that work in an environment with pollutants. Gasoline attendants are individuals that work in filling stations. They are constantly exposed to gasoline fumes and automobile engine products from vehicle exhaust. This increases the risk of acute and chronic respiratory diseases and carcinogenesis among them. The risk of health complications tends to increase with the duration of exposure. The study aimed to determine the proportion of gasoline attendants with lung function impairment. Methods and Materials: Two hundred and eight eligible participants were recruited for this study. A cross-sectional analytical study was carried out in Esan West local government area of Edo state, Nigeria. The study was carried out for a period of six months from December 2015 to May 2016. A questionnaire was used to obtain information on demographic characteristics, work history, mode of exposure and duration of exposure to petrol fumes. Lung function was assessed using a DTspiro spirometer (Model POP 10. Serial no 110843-005);also the anthropometric parameters of the respondent were measured. Statistical analysis was done using IBM SPSS version 20.0. Frequency and percentages were used to present categorical data. The mean and standard deviation of continuous variables were calculated and compared using the student’s t-test. The criteria of significant association were assumed for a p-value less than 0.05. Results: A total of one hundred and forty petrol pump attendants and one hundred and forty controls participated in this study. The mean age for petrol pump attendants was 24 ± 3.1 years and 23 ± 2.8 years for the control group. There were no significant differences in the gender distribution and anthropometric parameters as observed in this study. The lung impairment pattern observed in this study was obstructive in twelve (8.6%) gasoline pump attendants and restrictive pattern in thirty-nine (27.9%) gasoline pump attendants, while only four (2.9%) had an obstructive pattern and twelve (8.6%) had a restrictive pattern of lung impairment among the control group. This implies that a restrictive pattern was predominant. This study also observed that there was an increase in the number of gasoline pump attendants with declined lung function compared to the control group. Conclusion: Restrictive pattern of lung impairment was more predominant than the obstructive pattern among gasoline pump attendants. As a result, public health interventions should be instituted among these individuals, especially in developing countries.

Lung Function Impairment among Gasoline Attendants: A Cross-Sectional Study

Background: Occupational health is an important consideration, especially for people that work in an environment with pollutants. Gasoline attendants are individuals that work in filling stations. They are constantly exposed to gasoline fumes and automobile engine products from vehicle exhaust. This increases the risk of acute and chronic respiratory diseases and carcinogenesis among them. The risk of health complications tends to increase with the duration of exposure. The study aimed to determine the proportion of gasoline attendants with lung function impairment. Methods and Materials: Two hundred and eight eligible participants were recruited for this study. A cross-sectional analytical study was carried out in Esan West local government area of Edo state, Nigeria. The study was carried out for a period of six months from December 2015 to May 2016. A questionnaire was used to obtain information on demographic characteristics, work history, mode of exposure and duration of exposure to petrol fumes. Lung function was assessed using a DTspiro spirometer (Model POP 10. Serial no 110843-005);also the anthropometric parameters of the respondent were measured. Statistical analysis was done using IBM SPSS version 20.0. Frequency and percentages were used to present categorical data. The mean and standard deviation of continuous variables were calculated and compared using the student’s t-test. The criteria of significant association were assumed for a p-value less than 0.05. Results: A total of one hundred and forty petrol pump attendants and one hundred and forty controls participated in this study. The mean age for petrol pump attendants was 24 ± 3.1 years and 23 ± 2.8 years for the control group. There were no significant differences in the gender distribution and anthropometric parameters as observed in this study. The lung impairment pattern observed in this study was obstructive in twelve (8.6%) gasoline pump attendants and restrictive pattern in thirty-nine (27.9%) gasoline pump attendants, while only four (2.9%) had an obstructive pattern and twelve (8.6%) had a restrictive pattern of lung impairment among the control group. This implies that a restrictive pattern was predominant. This study also observed that there was an increase in the number of gasoline pump attendants with declined lung function compared to the control group. Conclusion: Restrictive pattern of lung impairment was more predominant than the obstructive pattern among gasoline pump attendants. As a result, public health interventions should be instituted among these individuals, especially in developing countries.

垄上交错种植密度对花生群体生长及产量的影响

为构建高产花生群体模式,根据花生品种类型调整垄上交错单粒种植模式下的合理种植密度。以半匍匐型花生品种扶余四粒红和直立型花生品种吉花17为材料,研究垄上交错单粒种植密度对花生植株性状、群体结构变化及产量的影响。共设置6个种植密度M1(23.85万株/hm^(2))、M2(20.84万株/hm^(2))、M3(18.52万株/hm^(2))、M4(16.66万株/hm^(2))、M5(13.89万株/hm^(2))、M6(11.91万株/hm^(2)),以双粒播种(23.85万株/hm^(2))为对照(CK)。对不同种植密度下各花生品种的植株性状、SPAD值、单株干物质积累量及产量性状等进行测定。随着种植密度的降低,两品种主茎高和侧枝长逐渐增高,半匍匐型花生品种四粒红在M6密度下的主茎高和侧枝长最高,直立型花生品种吉花17会随着种植密度的降低而先增加后降低的趋势,在M5密度下的主茎高和侧枝长最高。随着种植密度的降低,两品种在结荚期和成熟期的SPAD值呈先下降后上升的趋势。四粒红成熟期M4、M5、M6处理的地上和地下单株干物质积累量均显著高于CK。吉花17在生育后期M4处理下的地上和地下单株干物质积累量较CK有显著提升,成熟期分别较对照提高了155.35%、23.31%。此外,随着密度的降低,四粒红的产量呈先上升后下降的趋势,单株饱果数、百果质量和单株荚果产量均呈上升后下降的趋势,千克果数各密度处理低于CK;吉花17的产量整体上呈下降的趋势,单株饱果数、单株荚果产量均呈上升趋势,千克果数各处理均小于CK。垄上交错+单粒播种种植模式相对于双粒种植模式可以增加花生株高、SPAD值、干物质积累量,同时提高了产量。应用垄上交错种植时,应根据花生品种类型选择适宜的播种密度,半匍匐型花生品种以M4密度最佳,直立型花生品种以M2密度最佳。

交叉扩散驱动的SI模型空间斑图

目前国内外关于SI模型空间格局的研究大多数局限在自扩散以及系统参数对斑图模式的影响,而关于交叉扩散对空间格局的演化机理研究成果较少.本文建立了一个具有自扩散和交叉扩散的空间流行病模型,研究了在有无自扩散驱动系统不稳定的情况下,交叉扩散对SI模型的稳定性、稳定速度以及斑图结构的影响.研究发现,在无自扩散驱动系统不稳定的情况下,引入交叉扩散能够激发Turing斑图的产生;在自扩散驱动系统不稳定的情况下,交叉扩散可以实现斑图结构的改变;对于SI模型的稳定速度,不论有无自扩散驱动系统不稳定,交叉扩散都影响了其到达稳定所需时间,且在不同的交叉扩散系数下,所需时间也不同.因此,交叉扩散对于SI模型的稳定性、稳定速度、斑图结构都有重要的影响.

新发展格局下跨境电商上市企业创新绩效测度研究

随着全球化经济的不断发展,跨境电商凭借其创新发展模式成为了国内国际双循环新发展格局的重要力量。研究使用数据包络分析(data envelopment analysis, DEA)模型测度了52家不同行业的跨境电商上市企业创新水平。结果表明:商贸跨境电商企业的创新绩效水平一直维持在较低水平,制造业电商企业自2020年创新绩效显著提升,机械制造企业达到了较高水平。据此,提出优化跨境贸易政策,加快政企融合发展;建立技术保障机制,打造企业优质品牌;构建企业商贸群模式,扩大集群规模优势的政策建议。

我国城市成年居民早餐食物种类调查

目的:分析我国城市居民早餐食物食用情况及影响因素,为相关部门及供餐企业指导、改善居民早餐状况提供科学参考。方法:问卷调查早餐食物摄入和人口、社会经济学等相关信息。共纳入31省、自治区、直辖市城市居民10444人。应用SAS 9.4软件进行统计分析,并采用多因素Logistic回归模型分析早餐是否营养充足的影响因素。结果:10444名城市成年居民在调查期间早餐食用比例最高的食物是谷薯类(89.4%),其次是肉蛋类(53.9%)、奶豆坚果类(49.3%),最低的是蔬菜水果(42.2%)。分别有26.5%、28.8%、28.2%、16.5%的调查对象早餐的食物种类为1类、2类、3类、4类。不同城市、性别、年龄、婚姻状况、文化程度、家庭人均年收入之间差异均有统计学意义(P均<0.001)。多因素Logistic回归分析结果显示,一线及新一线城市、女性、30岁~、40岁~、50~80岁、家庭人均年收入≥7万元的调查对象早餐营养充足(早餐食物种类达到四类)的可能性更高。结论:我国居民早餐膳食不够均衡,早餐质量还有待提高。需要个人-供餐企业-相关部门等共同努力,达到均衡膳食、合理营养的目标。

虚拟现实技术下湘西花瑶挑花图案的数字化展示设计

花瑶挑花是湖南省隆回县瑶族非遗技艺。研究利用虚幻引擎(UE4)搭建数字化展示系统,呈现花瑶挑花典型图案及寓意,通过视听设计,使用户沉浸于虚拟现实的界面,实现对花瑶挑花文化遗产的保护和传承。

“跨文化”视阈下近代染织设计嬗变——以陈之佛为例

受西方艺术运动思潮影响,近代中国在西方各国的文化输入与国内染织设计需求的外因内需共同作用下,染织设计与图案学体系在继承中国传统造物精神基础上参照西方现代设计理论,在探索中逐步创新形成中国本土化染织设计与图案学体系。以陈之佛为例,通过研究陈之佛近代染织设计图稿、相关教材与报纸文稿、尚美图案馆等相关实物资料,总结出在受“跨文化”影响下染织设计从初始借鉴、融合吸收再到逐步探索创新的嬗变过程,设计范式从适应传统手工业模式逐渐转变为服务于机械化生产,同时也开始注重美育与图案科教学以培养独立设计人才。这种既吸纳西方设计思想又继承中国传统“民族性”文化的模式创新对现代设计发展创新有着重要的借鉴作用,为新时代“中国风格”的构建提供了重要的思想启发。

新发展格局下跨区域高等教育开放合作的特征与路径

跨区域高等教育开放合作可以打破国别地域的限制,对于加快优质资源共建共享、增进国际理解和文化交流互鉴等具有现实意义。其经历了从无到有、从发展到成熟的过程,在发起主体、地域及合作内容上发生了极大转变,至今仍然是全球化最为活跃的内容之一。国外跨区域高等教育开放合作注重多元主体自下而上参与、联合开发国际化特色课程、师生跨区域流动,以及将语言和文化相交融。我国经过长期探索与实践,在跨区域高等教育合作中展现出文化适应性、领域灵活性、主体多边性和政策主导性等典型特征。立足新发展格局,需要树立对外开放新理念,多维度拓宽跨区域高等教育开放合作领域,以数字赋能跨区域高等教育开放合作转型,进一步完善高等教育对外开放体制机制,建构起兼容并蓄的语言体系。