Deterministic compartment models(CMs)and stochastic models,including stochastic CMs and agent-based models,are widely utilized in epidemic modeling.However,the relationship between CMs and their corresponding stochast...Deterministic compartment models(CMs)and stochastic models,including stochastic CMs and agent-based models,are widely utilized in epidemic modeling.However,the relationship between CMs and their corresponding stochastic models is not well understood.The present study aimed to address this gap by conducting a comparative study using the susceptible,exposed,infectious,and recovered(SEIR)model and its extended CMs from the coronavirus disease 2019 modeling literature.We demonstrated the equivalence of the numerical solution of CMs using the Euler scheme and their stochastic counterparts through theoretical analysis and simulations.Based on this equivalence,we proposed an efficient model calibration method that could replicate the exact solution of CMs in the corresponding stochastic models through parameter adjustment.The advancement in calibration techniques enhanced the accuracy of stochastic modeling in capturing the dynamics of epidemics.However,it should be noted that discrete-time stochastic models cannot perfectly reproduce the exact solution of continuous-time CMs.Additionally,we proposed a new stochastic compartment and agent mixed model as an alternative to agent-based models for large-scale population simulations with a limited number of agents.This model offered a balance between computational efficiency and accuracy.The results of this research contributed to the comparison and unification of deterministic CMs and stochastic models in epidemic modeling.Furthermore,the results had implications for the development of hybrid models that integrated the strengths of both frameworks.Overall,the present study has provided valuable epidemic modeling techniques and their practical applications for understanding and controlling the spread of infectious diseases.展开更多
Researchers around the world strive to communicate new knowledge,primarily via publication,with the abstract being crucial in conveying core insights.Previous research has generally analyzed the discourse features of ...Researchers around the world strive to communicate new knowledge,primarily via publication,with the abstract being crucial in conveying core insights.Previous research has generally analyzed the discourse features of abstracts from a macro perspective and often employed either outdated texts,such as those over a decade old,or papers written by authors with lower English academic writing proficiency as research material.In this study,we analyzed forty abstracts from leading journals in applied linguistics,evenly split between Chinese and international journals.It revealed that the use of nominalization in abstracts by Chinese and international scholars showed similarities due to the universal academic requirement for conciseness.However,due to cultural and educational differences,each group differed in their respective language choices and nominalization usage.By analyzing the application of nominalization in different cultural contexts,the results of our study offered practical suggestions for crafting abstracts that effectively convey information,thereby,contributing to the broader academic community.展开更多
This paper analyzes and compares the key factors influencing food security in two populous countries(China and India),and cate-gorizes them into three types:agricultural production,economic development and income leve...This paper analyzes and compares the key factors influencing food security in two populous countries(China and India),and cate-gorizes them into three types:agricultural production,economic development and income level,and income distribution.Using the prevalence of undernourishment as an indicator of food security,the paper empirically tests the degree of impact of various factors on food security in both countries using Tobit regression and Newey regression methods.The study finds that improving the level of economic development can significantly enhance food security in both countriesꎻreducing the Gini coefficient has a significant impact on India,but not on Chinaꎻincreasing the agricultural production per capita has a much greater effect on China than on India.Therefore,both countries should take measures that are both similar and different according to their national conditions to improve their food security level.展开更多
Data compression plays a key role in optimizing the use of memory storage space and also reducing latency in data transmission. In this paper, we are interested in lossless compression techniques because their perform...Data compression plays a key role in optimizing the use of memory storage space and also reducing latency in data transmission. In this paper, we are interested in lossless compression techniques because their performance is exploited with lossy compression techniques for images and videos generally using a mixed approach. To achieve our intended objective, which is to study the performance of lossless compression methods, we first carried out a literature review, a summary of which enabled us to select the most relevant, namely the following: arithmetic coding, LZW, Tunstall’s algorithm, RLE, BWT, Huffman coding and Shannon-Fano. Secondly, we designed a purposive text dataset with a repeating pattern in order to test the behavior and effectiveness of the selected compression techniques. Thirdly, we designed the compression algorithms and developed the programs (scripts) in Matlab in order to test their performance. Finally, following the tests conducted on relevant data that we constructed according to a deliberate model, the results show that these methods presented in order of performance are very satisfactory:- LZW- Arithmetic coding- Tunstall algorithm- BWT + RLELikewise, it appears that on the one hand, the performance of certain techniques relative to others is strongly linked to the sequencing and/or recurrence of symbols that make up the message, and on the other hand, to the cumulative time of encoding and decoding.展开更多
In the digital age, the data exchanged within a company is a wealth of knowledge. The survival, growth and influence of a company in the short, medium and long term depend on it. Indeed, it is the lifeblood of any mod...In the digital age, the data exchanged within a company is a wealth of knowledge. The survival, growth and influence of a company in the short, medium and long term depend on it. Indeed, it is the lifeblood of any modern company. A companys operational and historical data contains strategic and operational knowledge of ever-increasing added value. The emergence of a new paradigm: big data. Today, the value of the data scattered throughout this mother of knowledge is calculated in billions of dollars, depending on its size, scope and area of intervention. With the rise of computer networks and distributed systems, the threats to these sensitive resources have steadily increased, jeopardizing the existence of the company itself by drying up production and losing the interest of customers and suppliers. These threats range from sabotage to bankruptcy. For several decades now, most companies have been using encryption algorithms to protect and secure their information systems against the threats and dangers posed by the inherent vulnerabilities of their infrastructure and the current economic climate. This vulnerability requires companies to make the right choice of algorithms to implement in their management systems. For this reason, the present work aims to carry out a comparative study of the reliability and effectiveness of symmetrical and asymmetrical cryptosystems, in order to identify one or more suitable for securing academic data in the DRC. The analysis of the robustness of commonly used symmetric and asymmetric cryptosystems will be the subject of simulations in this article.展开更多
By introducing the analytic hierarchy process (AHP), a model is constructed to compare the logistics development level of cold chain for agricultural products between China and other developed countries such as Unit...By introducing the analytic hierarchy process (AHP), a model is constructed to compare the logistics development level of cold chain for agricultural products between China and other developed countries such as United States, Japan and Euro- pean. The paper makes a comparative study on the development levels of agricultural cold chain logistics in China and developed countries from the aspects of the level of cold chain logistics facilities and equipments, the degree of cold chain logistics market-oriented and the capacity of cold chain logistics, then determines the problems of cold chain logistics in China. With the experiences learning from developed countries, some countermeasures are proposed to resolve those problems of cold chain logistics for agricultural products development combining with the national conditions in China.展开更多
Simile, as a kind of commonly used rhetoric, plays a vital role in people's daily life. The appropriate using of simile can make language much more refine, veracious, and lifelike, can vividly present the person, the...Simile, as a kind of commonly used rhetoric, plays a vital role in people's daily life. The appropriate using of simile can make language much more refine, veracious, and lifelike, can vividly present the person, the thing, the scene and so on to achieve better effects. Simile makes the finishing point in Chinese and English. However, because of the differences on culture, history, geography, customs, expressing ways and so on, there are some structural differences between Chinese and English simile. This paper will carry out the comparative study on the structure of Chinese and English simile.展开更多
[Objective] The aim was to discuss the classification of agricultural informatization in some developed countries, and conclude the revelation to Chinese agricultural informatization. [Method] The research was made by...[Objective] The aim was to discuss the classification of agricultural informatization in some developed countries, and conclude the revelation to Chinese agricultural informatization. [Method] The research was made by comparison, according to the development impetus. [Result] The results show that foreign agricultural informatization is mainly divided into three categories: the first category is the government leading; the second category is the industry self-help; the third category is typical demonstration. Since the reform and opening, Chinese agricultural informatization has made considerable achievements. [Conclusion] The agricultural informatization is significant to promote the update of the traditional agriculture, and it is also essential to Chinese agricultural sustainability.展开更多
Objective Comparative study on the feasibility,safety and outcome of transradial artery and transfemoral artery access for primary percutaneous coronary intervention (PCI) in patients with acute myocardial infarction(...Objective Comparative study on the feasibility,safety and outcome of transradial artery and transfemoral artery access for primary percutaneous coronary intervention (PCI) in patients with acute myocardial infarction(AMI).Methods Two hundred and eight patients with AMI episoded within 12 hours, male 159, female 49, age 58.9 ±11.9 (34~88)years, were randomly divided into transradial artery access for primary PCI (TRA pPCI) group of 106 cases and transfemoral artery access for PCI (TFA pPCI) group of 102 cases during Sept, 2000 to Aug, 2002. The protocols of the manipulation duration and the effect for TRA pPCI and TFA pPCI procedures were respectively compared, including the time of transradial artery puncture and the rate of puncture success at first time ; the time of guiding catheter engaging into target coronary ostium; the rate of patence in infarct related artery (IRA); total duration of manipulation and the successful rate.The incidence of complications such as bleeding, vessel injury,thrombi and embolism as well as the average stay of hospitalization between two groups was compared. The status and the incidance of vessel spasm were observed and the effect of medicine administration to prevent from and relieve the vascular spasm was evaluated. The time of Allen’s test before and after TRA pPCI , the inner diameter and the peak of blood velocity of the right and left radial artery were investigated with color Doppler vessel echography as well as the complications of radial artery were followed up 1 month after TRA pPCI procedure. Results Two cases in every TRA pPCI and TFA pPCI groups were crossed over each other because procedure of the transradial or transfemoral access was failure. One handred and six vessels (48 vessels in LAD,22 vessels in LCX and 36 vessels in RCA) associated with 28 vessels of total occlusion in TRA pPCI group and 102 vessels (51 vessels in LAD,18 veesles in LCX and 33 vessels in RCA) with 24 vessels in total occlusion in TFA pPCI group were angioplasticized . The successful rates of the first time puncture in access artery, the re patence IRA and pPCI were similar in TRA pPCI and TFA pPCI groups ( 93.4% vs 96.1% ;100% vs 100%; 96.2% vs 97.1% , P >0.05 ). There were no significant diffierence in the average time of puncture time of access artery ,engaging in target vessels of guiding catheters and the total procedure of PCI between the two groups ( 1.3 ±0.3s vs 1.2 ±0.3s ; 6.0 ±1.6min vs 5.8 ±0.9min ; 49.2 ±24.1min vs 46.5 ± 26.4min , P >0.05 ). The access artery complications such as bleeding ,hematoma and embolism as well the veneous thrombosis in TFA pPCI group were much more than those in TRA pPCI group(p< 0.01 ). Although slight artery spasm of 4.7% cases in TRA pPCI group was happened during the procedure of PCI , the procedure had being continued after administration of medicine to release the spasm. The time of Allen’s test ,diameter and the systolic velocity of blood in daul radial arteries were no significant change before and after pPCI.Conclusions The duration and effect by TRA pPCI for AMI with stable hemodynamics was similar to TFA pPCI. The complications such as of bleeding,vessel injury, thrombi and embolism by TRA pPCI were few, and it was unnecessary to discontinue the anticoagulation medicine. TRA pPCI might be selected as a access vessel for pPCI in AMI patients with stable hemodynamics.展开更多
Effective teaching has always been a goal pursued by teachers as a part of education both from the western and eastern society,for it to some extend is considered an effective way to improve society.In this essay,both...Effective teaching has always been a goal pursued by teachers as a part of education both from the western and eastern society,for it to some extend is considered an effective way to improve society.In this essay,both Chinese and western conceptions of teaching and learning will be discussed.In doing so,their differences and similarities can be seen clearly,which will help the cross-cultural educators to understand their teaching environment and learning styles.展开更多
A comparative study is conducted to compare the theory and application effect of two accident causation models, the human factors analysis and classification system(HFACS) and the accident causation "2-4" model(2...A comparative study is conducted to compare the theory and application effect of two accident causation models, the human factors analysis and classification system(HFACS) and the accident causation "2-4" model(24 Model), as well as to provide a reference for safety researchers and accident investigators to select an appropriate accident analysis method. The two models are compared in terms of their theoretical foundations, cause classifications, accident analysis processes, application ranges, and accident prevention strategies. A coal and gas outburst accident is then analyzed using both models, and the application results are compared. This study shows that both the 24 Model and HFACS have strong theoretical foundations, and they can each be applied in various domains. In addition, the cause classification in HFACS is more practical, and its accident analysis process is more convenient. On the other hand, the 24 Model includes external factors, which makes the cause analysis more systematic and comprehensive. Moreover, the 24 Model puts forward more corresponding measures to prevent accidents.展开更多
INTRODUCTIONHepatitis B viral infection, one of the most-prevalent liver disorders in China and Korea, is aserious infectious disease as it has the potential ofprogressing into liver cirrhosis and primary hepaticcarci...INTRODUCTIONHepatitis B viral infection, one of the most-prevalent liver disorders in China and Korea, is aserious infectious disease as it has the potential ofprogressing into liver cirrhosis and primary hepaticcarcinoma. China and Korea both belong to high-risk endemic regions of viral hepatitis[1]. TheHBsAg positive rates in China ranged from 6.9% -17.9% by age, race and test methods[2-5].展开更多
Determining the main controlling factors of earthquake-triggered geohazards is a prerequisite for studying earthquake geohazards and post-disaster emergency response.By studying these factors,the geomorphic and geolog...Determining the main controlling factors of earthquake-triggered geohazards is a prerequisite for studying earthquake geohazards and post-disaster emergency response.By studying these factors,the geomorphic and geological factors controlling the nature,condition,and distribution of earthquake-induced geohazards can be analyzed.Such insights facilitate earthquake disaster prediction and emergency response planning.The authors combined field investigations and spatial data analysis to examine geohazards induced by seismic events,examining ten earthquakes including the Wenchuan,Yushu,Lushan events,to elucidate the main control factors of seismic geohazard.The authors observed that seismic geohazard occurrence is usually affected by many factors,among which active nature of the seismogenic fault,seismic peak ground acceleration(PGA),topographic slope and geomorphic height differences,and distance from the fault zone and river system are the most important.Compared with strike-slip earthquakes,thrust earthquakes induce more high-altitude and high-speed remote landslides,which can cause great harm.Slopes of 0°–40°are prone to secondary seismic geohazards,which are mainly concentrated 0–6 km from the river system.Secondary geohazards are not only related to seismogenic fault but also influenced by the associated faults in the earthquake area.The maximum seismic PGA and secondary seismic geohazard number are positively correlated,and the horizontal and vertical ground motions play leading and promoting roles in secondary geohazard formation,respectively.Through the research,the spatial distribution of seismic geohazards is predicted,providing a basis for the formulation of emergency response plans following disasters.展开更多
Species compositions in the mangrove habitats of China and India, especially on Hainan Island (China) and on the Sun- darbans and the Andaman & Nicobar Islands (India), are of interest, showing several similariti...Species compositions in the mangrove habitats of China and India, especially on Hainan Island (China) and on the Sun- darbans and the Andaman & Nicobar Islands (India), are of interest, showing several similarities and differences. The total mangrove areas of India cover about 6419 km^2 with 43 species (23 major and 20 minor species), while the mangrove areas of China cover about 150 km^2 with 26 speices (19 major and 7 minor speices). We carried out a comparison of mangrove floras in the Indian Sundarbans, Andaman & Nicobar Islands and in Hainan Island. The mangrove areas of the Indian Sundarbans comprise about 66.5% of the total Indian mangroves, presently covering an area of 4267 km^2 with 35 species from 22 genera and 16 families. There are 34 species from 17 genera and l 3 families in the Andaman & Nicobar Islands. Hainan Island is considered a distribution center of mangroves; it has the largest number of mangrove species in China, i.e., 25 species from 15 genera and 12 families, accounting for about 96% of the total number of mangrove species in China. The mangroves of Hainan Island and the Andaman & Nicobar Islands belong to island types, while those of Sundarbans belong to inter-tidal deltaic types. Differences in soil type, rainfall, temperature, tidal fluctuation and other climatic features possibly cause variations in floristic composition of these regions.展开更多
Based on the questionnaire investigation, the authors make a comparative study on local residents′ perception of tourism impacts in Xidi, Zhouzhuang and Jiuhua Mountain. The result shows that residents of the three p...Based on the questionnaire investigation, the authors make a comparative study on local residents′ perception of tourism impacts in Xidi, Zhouzhuang and Jiuhua Mountain. The result shows that residents of the three places tend to have strong and consistent perception of its positive economic, socio-cultural and environmental impacts, but distinctly diverse ones of its negative impacts. Residents in Xidi and Zhouzhuang also have noticeable perception of its negative environmental impacts while those in Jiuhua Mountain have weaker perception of them. The research confirms the fact that residents are more liable to have positive perceptions at the early stage of the life cycle of the tourist places. The authors conclude that there exists a nonlinear relationship between residents′ perception and tourism development stages, and that tourism socio-cultural impact may appear at an early stage of tourism development instead of being no universal.展开更多
Determination of distribution and magnitude of active earth pressure is crucial in retaining wall designs. A number of analytical theories on active earth pressure were presented. Yet, there are limited studies on com...Determination of distribution and magnitude of active earth pressure is crucial in retaining wall designs. A number of analytical theories on active earth pressure were presented. Yet, there are limited studies on comparison between the theories. In this work, comparison between the theories with finite element analysis is done using the PLAXIS software. The comparative results show that in terms of distribution and magnitude of active earth pressure, RANKINE's theory possesses the highest match to the PLAXIS analysis. Parametric studies were also done to study the responses of active earth pressure distribution to varying parameters Increasing soil friction angle and wall friction causes decrease in active earth pressure. In contrast, active earth pressure increases with increasing soil unit weight and height of wall. RANK/NE's theory has the highest compatibility to finite element analysis among all theories, and utilization of this theory leads to proficient retaining wall design.展开更多
Fault diagnosis of liquid rocket propulsion systems (LRPSs) is a very important issue in space launch activities particularly when manned space missions are accompanied, since the safety and reliability can be signi...Fault diagnosis of liquid rocket propulsion systems (LRPSs) is a very important issue in space launch activities particularly when manned space missions are accompanied, since the safety and reliability can be significantly enhanced by exploiting an efficient fault diagnosis system. Currently, inverse problem-based diagnosis has attracted a great deal of research attention in fault diagnosis domain. This methodology provides a new strategy to model-based fault diagnosis for monitoring the health of propulsion systems. To solve the inverse problems arising from the fault diagnosis of LRPSs, GAs have been adopted in recent years as the first and effective choice of available numerical optimization tools. However, the GA has many control parameters to be chosen in advance and there still lack sound theoretical tools to analyze the effects of these parameters on diagnostic performance analytically. In this paper a comparative study of the influence of GA parameters on diagnostic results is conducted by performing a series of numerical experiments. The objective of this study is to investigate the contribution of individual algorithm parameter to final diagnostic result and provide reasonable estimates for choosing GA parameters in the inverse problem-based fault diagnosis of LRPSs. Some constructive remarks are made in conclusion and will be helpful for the implementation of GA to the fault diagnosis practice of LRPSs in the future.展开更多
Hydrogenated silicon carbide films (SiC:H) were deposited using the electron cyclotron resonance chemical vapour deposition (ECR-CVD) technique from a mixture of methane, silane and hydrogen, and using diborane and ph...Hydrogenated silicon carbide films (SiC:H) were deposited using the electron cyclotron resonance chemical vapour deposition (ECR-CVD) technique from a mixture of methane, silane and hydrogen, and using diborane and phosphine as doping gases. The effects of changes in the microwave power on the deposition rate and optical bandgap were investigated, and variations in the photoand dark-conductivities and activation energy were studied in conjunction with film analysis using the Raman scattering technique. In the case of boron-doped samples, the conductivity increased rapidly to a maximum, followed by rapid reduction at high microwave power. The ratio of the photo- to dark-conductivity (σph/σd) peaked at microwave power of ~600 W. Under conditions of high microwave power, Raman scattering analysis showed evidence of the formation and increase in the silicon microcrystalline and diamond-like phases in the films, the former of which could account for the rapid increase and the latter the subsequent decrease in the conductivity.In the case of phosphorusdoped SiC:H samples, it was found that increase in the microwave power has the effect of enhancing the formation of the silicon microcrystalline phase in the films which occurred in correspondence to a rapid increase in the conductivity and reduction in the activation energy The conductivity increase stabilised in samples deposited at microwave power exceeding 500 W probably as a result of dopant saturation. Results from Raman scattering measurements also showed that phosphorus doping had the effect of enhancing the formation of the silicon microcrystals in the film whereas the presence of boron had the effect of preserving the amorphous structure.展开更多
As the significant regional development driving, industry agglomeration has become one of the most interested for industrial economist and regional economist. This paper chooses the main five E&I industrial parks in ...As the significant regional development driving, industry agglomeration has become one of the most interested for industrial economist and regional economist. This paper chooses the main five E&I industrial parks in Shaanxi Province as the research object, and systematically compares their industry agglomerations, such as the situations, patterns, development approaches, and so on. Finally, based on the situation of the five E&I industrial parks, combined with the power and the attraction of sub-sectors industry, some suggestions on the formation and consolidation of agglomeration effect for each park are proposed.展开更多
Teacher autonomy has become a popular focus in the field of teacher education at present. The development of learner autonomy depends largely on teacher autonomy. Teacher autonomy is also one of the most effective way...Teacher autonomy has become a popular focus in the field of teacher education at present. The development of learner autonomy depends largely on teacher autonomy. Teacher autonomy is also one of the most effective ways to support teachers in their classroom practice, as well as to improve and expand their professional preparation and practices. Apart from that, the research of teacher autonomy at different phases of teachers' professional development may provide insight into how to strengthen their autonomy capability and to better understand the differences in teachers' development at different stages. The current study aims to explore the different level of how university novice and proficient English teachers see themselves as autonomous practitioners on the five dimensions of teacher autonomy: teaching autonomy, assessment autonomy, school management autonomy, professional development autonomy, and curriculum development autonomy. In addition, it proposes coping strategies to facilitate the development of teacher autonomy, which may shed some light on cultivating teacher autonomy for teachers at different developing stages, development of expertise, and teacher education.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.82173620 to Yang Zhao and 82041024 to Feng Chen)partially supported by the Bill&Melinda Gates Foundation(Grant No.INV-006371 to Feng Chen)Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Deterministic compartment models(CMs)and stochastic models,including stochastic CMs and agent-based models,are widely utilized in epidemic modeling.However,the relationship between CMs and their corresponding stochastic models is not well understood.The present study aimed to address this gap by conducting a comparative study using the susceptible,exposed,infectious,and recovered(SEIR)model and its extended CMs from the coronavirus disease 2019 modeling literature.We demonstrated the equivalence of the numerical solution of CMs using the Euler scheme and their stochastic counterparts through theoretical analysis and simulations.Based on this equivalence,we proposed an efficient model calibration method that could replicate the exact solution of CMs in the corresponding stochastic models through parameter adjustment.The advancement in calibration techniques enhanced the accuracy of stochastic modeling in capturing the dynamics of epidemics.However,it should be noted that discrete-time stochastic models cannot perfectly reproduce the exact solution of continuous-time CMs.Additionally,we proposed a new stochastic compartment and agent mixed model as an alternative to agent-based models for large-scale population simulations with a limited number of agents.This model offered a balance between computational efficiency and accuracy.The results of this research contributed to the comparison and unification of deterministic CMs and stochastic models in epidemic modeling.Furthermore,the results had implications for the development of hybrid models that integrated the strengths of both frameworks.Overall,the present study has provided valuable epidemic modeling techniques and their practical applications for understanding and controlling the spread of infectious diseases.
文摘Researchers around the world strive to communicate new knowledge,primarily via publication,with the abstract being crucial in conveying core insights.Previous research has generally analyzed the discourse features of abstracts from a macro perspective and often employed either outdated texts,such as those over a decade old,or papers written by authors with lower English academic writing proficiency as research material.In this study,we analyzed forty abstracts from leading journals in applied linguistics,evenly split between Chinese and international journals.It revealed that the use of nominalization in abstracts by Chinese and international scholars showed similarities due to the universal academic requirement for conciseness.However,due to cultural and educational differences,each group differed in their respective language choices and nominalization usage.By analyzing the application of nominalization in different cultural contexts,the results of our study offered practical suggestions for crafting abstracts that effectively convey information,thereby,contributing to the broader academic community.
基金Supported by the MOE(Ministry of Education in China)Project of Humanities and Social Sciences(19YJA790105).
文摘This paper analyzes and compares the key factors influencing food security in two populous countries(China and India),and cate-gorizes them into three types:agricultural production,economic development and income level,and income distribution.Using the prevalence of undernourishment as an indicator of food security,the paper empirically tests the degree of impact of various factors on food security in both countries using Tobit regression and Newey regression methods.The study finds that improving the level of economic development can significantly enhance food security in both countriesꎻreducing the Gini coefficient has a significant impact on India,but not on Chinaꎻincreasing the agricultural production per capita has a much greater effect on China than on India.Therefore,both countries should take measures that are both similar and different according to their national conditions to improve their food security level.
文摘Data compression plays a key role in optimizing the use of memory storage space and also reducing latency in data transmission. In this paper, we are interested in lossless compression techniques because their performance is exploited with lossy compression techniques for images and videos generally using a mixed approach. To achieve our intended objective, which is to study the performance of lossless compression methods, we first carried out a literature review, a summary of which enabled us to select the most relevant, namely the following: arithmetic coding, LZW, Tunstall’s algorithm, RLE, BWT, Huffman coding and Shannon-Fano. Secondly, we designed a purposive text dataset with a repeating pattern in order to test the behavior and effectiveness of the selected compression techniques. Thirdly, we designed the compression algorithms and developed the programs (scripts) in Matlab in order to test their performance. Finally, following the tests conducted on relevant data that we constructed according to a deliberate model, the results show that these methods presented in order of performance are very satisfactory:- LZW- Arithmetic coding- Tunstall algorithm- BWT + RLELikewise, it appears that on the one hand, the performance of certain techniques relative to others is strongly linked to the sequencing and/or recurrence of symbols that make up the message, and on the other hand, to the cumulative time of encoding and decoding.
文摘In the digital age, the data exchanged within a company is a wealth of knowledge. The survival, growth and influence of a company in the short, medium and long term depend on it. Indeed, it is the lifeblood of any modern company. A companys operational and historical data contains strategic and operational knowledge of ever-increasing added value. The emergence of a new paradigm: big data. Today, the value of the data scattered throughout this mother of knowledge is calculated in billions of dollars, depending on its size, scope and area of intervention. With the rise of computer networks and distributed systems, the threats to these sensitive resources have steadily increased, jeopardizing the existence of the company itself by drying up production and losing the interest of customers and suppliers. These threats range from sabotage to bankruptcy. For several decades now, most companies have been using encryption algorithms to protect and secure their information systems against the threats and dangers posed by the inherent vulnerabilities of their infrastructure and the current economic climate. This vulnerability requires companies to make the right choice of algorithms to implement in their management systems. For this reason, the present work aims to carry out a comparative study of the reliability and effectiveness of symmetrical and asymmetrical cryptosystems, in order to identify one or more suitable for securing academic data in the DRC. The analysis of the robustness of commonly used symmetric and asymmetric cryptosystems will be the subject of simulations in this article.
基金Supported by the Research Project of the Research Center of Hubei Logistics Development,China (2011A03)the Humanities and Social Sciences Project of Hubei Provincial Department of Education Project,China (2011jyty027)~~
文摘By introducing the analytic hierarchy process (AHP), a model is constructed to compare the logistics development level of cold chain for agricultural products between China and other developed countries such as United States, Japan and Euro- pean. The paper makes a comparative study on the development levels of agricultural cold chain logistics in China and developed countries from the aspects of the level of cold chain logistics facilities and equipments, the degree of cold chain logistics market-oriented and the capacity of cold chain logistics, then determines the problems of cold chain logistics in China. With the experiences learning from developed countries, some countermeasures are proposed to resolve those problems of cold chain logistics for agricultural products development combining with the national conditions in China.
文摘Simile, as a kind of commonly used rhetoric, plays a vital role in people's daily life. The appropriate using of simile can make language much more refine, veracious, and lifelike, can vividly present the person, the thing, the scene and so on to achieve better effects. Simile makes the finishing point in Chinese and English. However, because of the differences on culture, history, geography, customs, expressing ways and so on, there are some structural differences between Chinese and English simile. This paper will carry out the comparative study on the structure of Chinese and English simile.
文摘[Objective] The aim was to discuss the classification of agricultural informatization in some developed countries, and conclude the revelation to Chinese agricultural informatization. [Method] The research was made by comparison, according to the development impetus. [Result] The results show that foreign agricultural informatization is mainly divided into three categories: the first category is the government leading; the second category is the industry self-help; the third category is typical demonstration. Since the reform and opening, Chinese agricultural informatization has made considerable achievements. [Conclusion] The agricultural informatization is significant to promote the update of the traditional agriculture, and it is also essential to Chinese agricultural sustainability.
文摘Objective Comparative study on the feasibility,safety and outcome of transradial artery and transfemoral artery access for primary percutaneous coronary intervention (PCI) in patients with acute myocardial infarction(AMI).Methods Two hundred and eight patients with AMI episoded within 12 hours, male 159, female 49, age 58.9 ±11.9 (34~88)years, were randomly divided into transradial artery access for primary PCI (TRA pPCI) group of 106 cases and transfemoral artery access for PCI (TFA pPCI) group of 102 cases during Sept, 2000 to Aug, 2002. The protocols of the manipulation duration and the effect for TRA pPCI and TFA pPCI procedures were respectively compared, including the time of transradial artery puncture and the rate of puncture success at first time ; the time of guiding catheter engaging into target coronary ostium; the rate of patence in infarct related artery (IRA); total duration of manipulation and the successful rate.The incidence of complications such as bleeding, vessel injury,thrombi and embolism as well as the average stay of hospitalization between two groups was compared. The status and the incidance of vessel spasm were observed and the effect of medicine administration to prevent from and relieve the vascular spasm was evaluated. The time of Allen’s test before and after TRA pPCI , the inner diameter and the peak of blood velocity of the right and left radial artery were investigated with color Doppler vessel echography as well as the complications of radial artery were followed up 1 month after TRA pPCI procedure. Results Two cases in every TRA pPCI and TFA pPCI groups were crossed over each other because procedure of the transradial or transfemoral access was failure. One handred and six vessels (48 vessels in LAD,22 vessels in LCX and 36 vessels in RCA) associated with 28 vessels of total occlusion in TRA pPCI group and 102 vessels (51 vessels in LAD,18 veesles in LCX and 33 vessels in RCA) with 24 vessels in total occlusion in TFA pPCI group were angioplasticized . The successful rates of the first time puncture in access artery, the re patence IRA and pPCI were similar in TRA pPCI and TFA pPCI groups ( 93.4% vs 96.1% ;100% vs 100%; 96.2% vs 97.1% , P >0.05 ). There were no significant diffierence in the average time of puncture time of access artery ,engaging in target vessels of guiding catheters and the total procedure of PCI between the two groups ( 1.3 ±0.3s vs 1.2 ±0.3s ; 6.0 ±1.6min vs 5.8 ±0.9min ; 49.2 ±24.1min vs 46.5 ± 26.4min , P >0.05 ). The access artery complications such as bleeding ,hematoma and embolism as well the veneous thrombosis in TFA pPCI group were much more than those in TRA pPCI group(p< 0.01 ). Although slight artery spasm of 4.7% cases in TRA pPCI group was happened during the procedure of PCI , the procedure had being continued after administration of medicine to release the spasm. The time of Allen’s test ,diameter and the systolic velocity of blood in daul radial arteries were no significant change before and after pPCI.Conclusions The duration and effect by TRA pPCI for AMI with stable hemodynamics was similar to TFA pPCI. The complications such as of bleeding,vessel injury, thrombi and embolism by TRA pPCI were few, and it was unnecessary to discontinue the anticoagulation medicine. TRA pPCI might be selected as a access vessel for pPCI in AMI patients with stable hemodynamics.
文摘Effective teaching has always been a goal pursued by teachers as a part of education both from the western and eastern society,for it to some extend is considered an effective way to improve society.In this essay,both Chinese and western conceptions of teaching and learning will be discussed.In doing so,their differences and similarities can be seen clearly,which will help the cross-cultural educators to understand their teaching environment and learning styles.
基金support from the State Key Program of the National Natural Science Foundation of China (No. 51534008)
文摘A comparative study is conducted to compare the theory and application effect of two accident causation models, the human factors analysis and classification system(HFACS) and the accident causation "2-4" model(24 Model), as well as to provide a reference for safety researchers and accident investigators to select an appropriate accident analysis method. The two models are compared in terms of their theoretical foundations, cause classifications, accident analysis processes, application ranges, and accident prevention strategies. A coal and gas outburst accident is then analyzed using both models, and the application results are compared. This study shows that both the 24 Model and HFACS have strong theoretical foundations, and they can each be applied in various domains. In addition, the cause classification in HFACS is more practical, and its accident analysis process is more convenient. On the other hand, the 24 Model includes external factors, which makes the cause analysis more systematic and comprehensive. Moreover, the 24 Model puts forward more corresponding measures to prevent accidents.
基金Project supported by the National Natural Science Foundation of China, No. 39560074Korea ScienceEngineering Foundation, 965-0700-001-2.
文摘INTRODUCTIONHepatitis B viral infection, one of the most-prevalent liver disorders in China and Korea, is aserious infectious disease as it has the potential ofprogressing into liver cirrhosis and primary hepaticcarcinoma. China and Korea both belong to high-risk endemic regions of viral hepatitis[1]. TheHBsAg positive rates in China ranged from 6.9% -17.9% by age, race and test methods[2-5].
基金supported by the National Natural Science Foundation of China(41977258)the National Key Research and Development Program of China(2017YFC1501005 and 2018YFC1504704)。
文摘Determining the main controlling factors of earthquake-triggered geohazards is a prerequisite for studying earthquake geohazards and post-disaster emergency response.By studying these factors,the geomorphic and geological factors controlling the nature,condition,and distribution of earthquake-induced geohazards can be analyzed.Such insights facilitate earthquake disaster prediction and emergency response planning.The authors combined field investigations and spatial data analysis to examine geohazards induced by seismic events,examining ten earthquakes including the Wenchuan,Yushu,Lushan events,to elucidate the main control factors of seismic geohazard.The authors observed that seismic geohazard occurrence is usually affected by many factors,among which active nature of the seismogenic fault,seismic peak ground acceleration(PGA),topographic slope and geomorphic height differences,and distance from the fault zone and river system are the most important.Compared with strike-slip earthquakes,thrust earthquakes induce more high-altitude and high-speed remote landslides,which can cause great harm.Slopes of 0°–40°are prone to secondary seismic geohazards,which are mainly concentrated 0–6 km from the river system.Secondary geohazards are not only related to seismogenic fault but also influenced by the associated faults in the earthquake area.The maximum seismic PGA and secondary seismic geohazard number are positively correlated,and the horizontal and vertical ground motions play leading and promoting roles in secondary geohazard formation,respectively.Through the research,the spatial distribution of seismic geohazards is predicted,providing a basis for the formulation of emergency response plans following disasters.
基金supported by the National Natural Science Foundation of China (Grant No. 40701191)
文摘Species compositions in the mangrove habitats of China and India, especially on Hainan Island (China) and on the Sun- darbans and the Andaman & Nicobar Islands (India), are of interest, showing several similarities and differences. The total mangrove areas of India cover about 6419 km^2 with 43 species (23 major and 20 minor species), while the mangrove areas of China cover about 150 km^2 with 26 speices (19 major and 7 minor speices). We carried out a comparison of mangrove floras in the Indian Sundarbans, Andaman & Nicobar Islands and in Hainan Island. The mangrove areas of the Indian Sundarbans comprise about 66.5% of the total Indian mangroves, presently covering an area of 4267 km^2 with 35 species from 22 genera and 16 families. There are 34 species from 17 genera and l 3 families in the Andaman & Nicobar Islands. Hainan Island is considered a distribution center of mangroves; it has the largest number of mangrove species in China, i.e., 25 species from 15 genera and 12 families, accounting for about 96% of the total number of mangrove species in China. The mangroves of Hainan Island and the Andaman & Nicobar Islands belong to island types, while those of Sundarbans belong to inter-tidal deltaic types. Differences in soil type, rainfall, temperature, tidal fluctuation and other climatic features possibly cause variations in floristic composition of these regions.
基金Undertheauspicesof the Fund Project of Anhui Provincial Education Office (No. 2003kj155)
文摘Based on the questionnaire investigation, the authors make a comparative study on local residents′ perception of tourism impacts in Xidi, Zhouzhuang and Jiuhua Mountain. The result shows that residents of the three places tend to have strong and consistent perception of its positive economic, socio-cultural and environmental impacts, but distinctly diverse ones of its negative impacts. Residents in Xidi and Zhouzhuang also have noticeable perception of its negative environmental impacts while those in Jiuhua Mountain have weaker perception of them. The research confirms the fact that residents are more liable to have positive perceptions at the early stage of the life cycle of the tourist places. The authors conclude that there exists a nonlinear relationship between residents′ perception and tourism development stages, and that tourism socio-cultural impact may appear at an early stage of tourism development instead of being no universal.
基金Project(RG086/10AET) supported by the Institute of Research Management and Monitoring,University of Malaya,Malaysia
文摘Determination of distribution and magnitude of active earth pressure is crucial in retaining wall designs. A number of analytical theories on active earth pressure were presented. Yet, there are limited studies on comparison between the theories. In this work, comparison between the theories with finite element analysis is done using the PLAXIS software. The comparative results show that in terms of distribution and magnitude of active earth pressure, RANKINE's theory possesses the highest match to the PLAXIS analysis. Parametric studies were also done to study the responses of active earth pressure distribution to varying parameters Increasing soil friction angle and wall friction causes decrease in active earth pressure. In contrast, active earth pressure increases with increasing soil unit weight and height of wall. RANK/NE's theory has the highest compatibility to finite element analysis among all theories, and utilization of this theory leads to proficient retaining wall design.
基金This work was supported by the National Natural Science Foundation of China(No.50106005)
文摘Fault diagnosis of liquid rocket propulsion systems (LRPSs) is a very important issue in space launch activities particularly when manned space missions are accompanied, since the safety and reliability can be significantly enhanced by exploiting an efficient fault diagnosis system. Currently, inverse problem-based diagnosis has attracted a great deal of research attention in fault diagnosis domain. This methodology provides a new strategy to model-based fault diagnosis for monitoring the health of propulsion systems. To solve the inverse problems arising from the fault diagnosis of LRPSs, GAs have been adopted in recent years as the first and effective choice of available numerical optimization tools. However, the GA has many control parameters to be chosen in advance and there still lack sound theoretical tools to analyze the effects of these parameters on diagnostic performance analytically. In this paper a comparative study of the influence of GA parameters on diagnostic results is conducted by performing a series of numerical experiments. The objective of this study is to investigate the contribution of individual algorithm parameter to final diagnostic result and provide reasonable estimates for choosing GA parameters in the inverse problem-based fault diagnosis of LRPSs. Some constructive remarks are made in conclusion and will be helpful for the implementation of GA to the fault diagnosis practice of LRPSs in the future.
文摘Hydrogenated silicon carbide films (SiC:H) were deposited using the electron cyclotron resonance chemical vapour deposition (ECR-CVD) technique from a mixture of methane, silane and hydrogen, and using diborane and phosphine as doping gases. The effects of changes in the microwave power on the deposition rate and optical bandgap were investigated, and variations in the photoand dark-conductivities and activation energy were studied in conjunction with film analysis using the Raman scattering technique. In the case of boron-doped samples, the conductivity increased rapidly to a maximum, followed by rapid reduction at high microwave power. The ratio of the photo- to dark-conductivity (σph/σd) peaked at microwave power of ~600 W. Under conditions of high microwave power, Raman scattering analysis showed evidence of the formation and increase in the silicon microcrystalline and diamond-like phases in the films, the former of which could account for the rapid increase and the latter the subsequent decrease in the conductivity.In the case of phosphorusdoped SiC:H samples, it was found that increase in the microwave power has the effect of enhancing the formation of the silicon microcrystalline phase in the films which occurred in correspondence to a rapid increase in the conductivity and reduction in the activation energy The conductivity increase stabilised in samples deposited at microwave power exceeding 500 W probably as a result of dopant saturation. Results from Raman scattering measurements also showed that phosphorus doping had the effect of enhancing the formation of the silicon microcrystals in the film whereas the presence of boron had the effect of preserving the amorphous structure.
文摘As the significant regional development driving, industry agglomeration has become one of the most interested for industrial economist and regional economist. This paper chooses the main five E&I industrial parks in Shaanxi Province as the research object, and systematically compares their industry agglomerations, such as the situations, patterns, development approaches, and so on. Finally, based on the situation of the five E&I industrial parks, combined with the power and the attraction of sub-sectors industry, some suggestions on the formation and consolidation of agglomeration effect for each park are proposed.
文摘Teacher autonomy has become a popular focus in the field of teacher education at present. The development of learner autonomy depends largely on teacher autonomy. Teacher autonomy is also one of the most effective ways to support teachers in their classroom practice, as well as to improve and expand their professional preparation and practices. Apart from that, the research of teacher autonomy at different phases of teachers' professional development may provide insight into how to strengthen their autonomy capability and to better understand the differences in teachers' development at different stages. The current study aims to explore the different level of how university novice and proficient English teachers see themselves as autonomous practitioners on the five dimensions of teacher autonomy: teaching autonomy, assessment autonomy, school management autonomy, professional development autonomy, and curriculum development autonomy. In addition, it proposes coping strategies to facilitate the development of teacher autonomy, which may shed some light on cultivating teacher autonomy for teachers at different developing stages, development of expertise, and teacher education.