Time and Space Thinking that is composed of time and space thinking is brought up in civil engineering. This paper makes a detailed analysis on application and role of time and space thinking in knowledge system and l...Time and Space Thinking that is composed of time and space thinking is brought up in civil engineering. This paper makes a detailed analysis on application and role of time and space thinking in knowledge system and learning method of civil engineering and put forward time and space thinking to be similar with philosophical view of time and space. Time and space thinking is a scientific method, therefore, it is suggested to make students active in having such idea and strengthen students' understanding on time and space thinking, which will helping students recognize knowledge system and stimulate innovative abilities.展开更多
The film The Hours is a masterpiece that reflects female spiritual predicament and it analyzes the life exploration and death struggle of three women in three periods deeply.This research chooses this film as material...The film The Hours is a masterpiece that reflects female spiritual predicament and it analyzes the life exploration and death struggle of three women in three periods deeply.This research chooses this film as material to study female self consciousness.In this paper,female self consciousness is discussed in two aspects,namely,from limitation and span of time and space aspect,and from the certain image in this film.At the end of this paper,there is a clear conclusion,namely a suggestion for female who is suffering from how to do self consciousness.展开更多
A natural extension of the Lorentz transformation to its complex version was constructed together with a parallel extension of the Minkowski M<sup>4</sup> model for special relativity (SR) to complex C<...A natural extension of the Lorentz transformation to its complex version was constructed together with a parallel extension of the Minkowski M<sup>4</sup> model for special relativity (SR) to complex C<sup>4</sup> space-time. As the [signed] absolute values of complex coordinates of the underlying motion’s characterization in C<sup>4</sup> one obtains a Newtonian-like type of motion whereas as the real parts of the complex motion’s description and of the complex Lorentz transformation, all the SR theory as modeled by M<sup>4</sup> real space-time can be recovered. This means all the SR theory is preserved in the real subspace M<sup>4</sup> of the space-time C<sup>4</sup> while becoming simpler and clearer in the new complex model’s framework. Since velocities in the complex model can be determined geometrically, with no primary use of time, time turns out to be definable within the equivalent theory of the reduced complex C<sup>4</sup> model to the C<sup>3</sup> “para-space” model. That procedure allows us to separate time from the (para)space and consider all the SR theory as a theory of C<sup>3</sup> alone. On the other hand, the complex time defined within the C<sup>3</sup> theory is interpreted and modeled by the single separate C<sup>1</sup> complex plane. The possibility for application of the C<sup>3</sup> model to quantum mechanics is suggested. As such, the model C<sup>3</sup> seems to have unifying abilities for application to different physical theories.展开更多
A high contrast to noise ratio(CNR)is always desirable for contrast-enhanced computed tomography angiography(CTA).To ensure a high CNR of the vascular images in CTA and potentially reduce the radiation exposure and co...A high contrast to noise ratio(CNR)is always desirable for contrast-enhanced computed tomography angiography(CTA).To ensure a high CNR of the vascular images in CTA and potentially reduce the radiation exposure and contrast usage,an adaptive bolus chasing method is proposed and evaluated compared to the existing constant-speed method.The proposed method is based on a local time and space parameter varying model of the contrast bolus.Optimal scan time for the next segment of the vasculature is estimated and predicted in real time and guides the computed tomography(CT)scanner table movement that guarantees that each segment of the vasculature is scanned with the maximum possible enhancement.Simulations and experimental results show that the proposed bolus chasing method outperforms the conventional constant-speed method substantially.展开更多
Orthogonal Time Frequency and Space(OTFS) modulation is expected to provide high-speed and ultra-reliable communications for emerging mobile applications, including low-orbit satellite communications. Using the Dopple...Orthogonal Time Frequency and Space(OTFS) modulation is expected to provide high-speed and ultra-reliable communications for emerging mobile applications, including low-orbit satellite communications. Using the Doppler frequency for positioning is a promising research direction on communication and navigation integration. To tackle the high Doppler frequency and low signal-to-noise ratio(SNR) in satellite communication, this paper proposes a Red and Blue Frequency Shift Discriminator(RBFSD) based on the pseudo-noise(PN) sequence.The paper derives that the cross-correlation function on the Doppler domain exhibits the characteristic of a Sinc function. Therefore, it applies modulation onto the Delay-Doppler domain using PN sequence and adjusts Doppler frequency estimation by red-shifting or blue-shifting. Simulation results show that the performance of Doppler frequency estimation is close to the Cramér-Rao Lower Bound when the SNR is greater than -15dB. The proposed algorithm is about 1/D times less complex than the existing PN pilot sequence algorithm, where D is the resolution of the fractional Doppler.展开更多
Taking Sichuan Gymnasium Station as the research object, we explore land use characteristics over time of areas around Sichuan Gymnasium Station in terms of time. We extract the basic information of land use in areas ...Taking Sichuan Gymnasium Station as the research object, we explore land use characteristics over time of areas around Sichuan Gymnasium Station in terms of time. We extract the basic information of land use in areas around Sichuan Gymnasium Station in 2005, 2011, and 2016 through Google Earth in order to draw the map of land use status in three time nodes. We then analyze the degree of mixing and equilibrium, intensity of development of land, and land use patterns of areas around Sichuan Gymnasium Station with indexes including the area proportion of land use patterns, information entropy, and degree of equilibrium within a 1,000-m radius centered on the station, so as to reveal the spatial distribution characteristics of land around the station in different time nodes. Through comparative analysis, it is found that the development of rail transit has not significantly contributed to the boom of commerce and the development of the old city of Chengdu. We also analyze land use changes in areas around Sichuan Gymnasium Station in terms of space, and find that land use patterns in areas around commuter stations seem to be more complicated than that of the average station, and land use patterns in areas around Huaxiba Station and Nijiaqiao Station on Line 1, which opened first, are more complicated than that of Moziqiao Station and Yiguanmiao Station on Line 3. The original land use patterns formed in the old city often determine the selection of rail transit routes and rail transit stations. Adaptive stations do not play a decisive role in land use patterns in their surrounding areas, but have some impact on the plot ratio and building height of land for commercial use within the core area of the stations.展开更多
With the development of productive forces. the space evolution of regional economicSystem keeps closer links with the traffic transport line. A kind of linear space regional scathetic bodyforms constantly and develops...With the development of productive forces. the space evolution of regional economicSystem keeps closer links with the traffic transport line. A kind of linear space regional scathetic bodyforms constantly and develops rapidly. Relying on the traffic trunk lines, it aggregates and diffusesconstantly.At the same time, it mixes population, industry, town, interflow of commodities, interflowof energy and interflow of information together.This unique space regional synthetic body is calledtraffic economic belt (TEB). In the paper, the basic concepts, types and qualities of TEB wereelaborated and the life-circle theory was put forward creatively.展开更多
[Objectives]This study was conducted to accurately understand the spatial distribution of the outbreak of pine wood nematode disease,explore its spatial laws,and provide a more scientific and efficient analysis and de...[Objectives]This study was conducted to accurately understand the spatial distribution of the outbreak of pine wood nematode disease,explore its spatial laws,and provide a more scientific and efficient analysis and decision-making basis for the prevention and management of pine wood nematode disease.[Methods]Taking the GIS management of Bursaphelenchus xylophilus tree felling in Yiling District as an example,the spatial positions of epidemic wood in the two years from 2019 to 2020 were collected.The spatial data management function of ArcGIS software was used to collect point and surface layers.Spatial information maps were drawn by spatial visualization,trend surface,spatial autocorrelation,nearest neighbor distance index and spatial-temporal clustering analysis of kernel density,so as to intuitively understand the evolution of spatial pattern trend of pine wood nematode disease,and to explain the variation raw and diffusion characteristics of pine wood nematode disease.[Results](1)Under the control measures,the affected pine forests and epidemic sites(subcompartments)decreased in the following year,the spread of the epidemic was still spreading,which was spreading from the central to the western and northern regions.The distribution of the plane epidemic sites was sparse from high concentration.The new epidemic sites occurred in a jump,and the number of affected pine trees was high.The outbreak was concentrated in a certain area,and the risk was high.The natural transmission and diffusion would coexist for a long time.(2)The epidemic trend of pine nematode in the two years was in the east and west,with a high value in the east,and the trend line was almost straight line.The outbreak of pine nematode showed cone-shaped central point aggregation and spread.(3)The spatial and temporal clustering characteristics of the epidemic show spatial clustering in the overall pattern,high clustering of pine victims caused by the spread of the epidemic source and clustering distribution pattern of epidemic points.(4)In the two years,the damaged pine trees were searched within the range of 5 km by using the distance threshold.The kernel density maps showed that the damaged pine trees in 2019 were more serious than those in 2020.The result of density map was consistent with the nearest neighbor distance index,and the damaged pine forests were mainly concentrated.(5)The epidemic situation of B.xylophilus disease in this region has a certain number of epidemic sites and a wide distribution area,the epidemic situation is difficult to eradicate in a short time.On the comprehensive measures,we should increase the clearing of epidemic trees,block the spread of the epidemic situation in the new areas,reduce the epidemic sites,regulate the density of pine trees by forest management,reduce the density of Monochamus alternatus and establish a broad-leaved forest ecosystem.[Conclusions]The study provides assistive technology support for the prevention and control of pine wood nematode disease.展开更多
The objective of this paper is to utilize images of spatial and temporal fluctuations of temperature over the Earth to study the global climate variation. We illustrated that monthly temperature observations from weat...The objective of this paper is to utilize images of spatial and temporal fluctuations of temperature over the Earth to study the global climate variation. We illustrated that monthly temperature observations from weather stations could be decomposed as components with different time scales based on their spectral distribution. Kolmogorov-Zurbenko (KZ) filters were applied to smooth and interpolate gridded temperature data to construct global maps for long-term (≥ 6 years) trends and El Nino-like (2 to 5 years) movements over the time period of 1893 to 2008. Annual temperature seasonality, latitude and altitude effects have been carefully accounted for to capture meaningful spatiotemporal patterns of climate variability. The result revealed striking facts about global temperature anomalies for specific regions. Correlation analysis and the movie of thermal maps for El Nino-like component clearly supported the existence of such climate fluctuations in time and space.展开更多
According to the time&space conversion relations and different frequency phase detection principle,an ultra-high precision time&frequency measurement method is proposed in this paper.The higher accuracy and st...According to the time&space conversion relations and different frequency phase detection principle,an ultra-high precision time&frequency measurement method is proposed in this paper.The higher accuracy and stability of the speed of light and electromagnetic signals during the transmission in space or a specific medium enable the measurement of short time interval which uses the coincidence detection of signal’s transmission delay in length.The measurement precision better than 10 picoseconds can be easily obtained.The method develops the length vernier utilizing the stability of signal’s transmission delay,minimizes the fuzzy region of phase coincidence between the standard frequency signal and the measured signal,approaches the best phase coincidences and therefore improves the measurement precision which is higher than the precision provided by the traditional methods based on frequency processing.Besides,the method costs less than the traditional methods and can also solve the problem of the measurement of super-high frequency.Experimental results show the method can improve the measurement precision to 10 12/s in the time&frequency domain.展开更多
A Bloom filter is a space-efficient data structure used for concisely representing a set as well as membership queries at the expense of introducing false positive. In this paper, we propose the L-priorities Bloom fil...A Bloom filter is a space-efficient data structure used for concisely representing a set as well as membership queries at the expense of introducing false positive. In this paper, we propose the L-priorities Bloom filter (LPBF) as a new member of the Bloom filter (BF) family, it uses a limited multidimensional bit space matrix to replace the bit vector of standard bloom filters in order to support different priorities for the elements of a set. We demonstrate the time and space complexity, especially the false positive rate of LPBF. Furthermore, we also present a detailed practical evaluation of the false positive rate achieved by LPBF. The results show that LPBF performs better than standard BFs with respect to false positive rate.展开更多
[Objective] The research aimed to study the activity characteristics and climate rule of thunderstorm in Fujian Province.[Method] Based on the daily thunderstorm data in 67 meteorological stations of Fujian Province d...[Objective] The research aimed to study the activity characteristics and climate rule of thunderstorm in Fujian Province.[Method] Based on the daily thunderstorm data in 67 meteorological stations of Fujian Province during 1960-2007,the spatial and temporal distribution characteristics of thunderstorm in Fujian Province were analyzed by using the climate tendency rate,the trend coefficient and so on.[Result] The distribution of thunderstorm days showed the northeast-southwest direction and increased gradually from the coast to the inland in Fujian Province during 1960-2007.The high value zone was in Longyan,and the thunderstorm days in the coastal islands were the fewest.The thunderstorm days had the obvious decrease trend in Fujian Province in 48 years.The decrease speeds in the central coastal area and most of inland mountain area were 3.5 and 4.5 d/10 a.The decrease speed was 5.5 d/10 a in the north of Ningde,the east of Sanming and some areas in Nanping.The trend coefficient variation of thunderstorm days had the obvious regional characteristic.Especially the decrease trend in the inland mountain area was more obvious than that in the coast.The decrease of thunderstorm day trend coefficient in the north of Nanping was the most,and the trend coefficient was-0.65.But the decrease trend in the central coastal area wasn’t obvious,and the coefficient was only-0.15.The thunderstorm day had the obvious seasonal variation.The multi-occurrence period of thunderstorm was during March-september and reached the maximum value in August.Started from September,the thunderstorm quickly decreased.From October to February in next year,the thunderstorm happened seldom.The average first thunderstorm date in the northwest area was earlier than that in the southeast area.The difference of average final thunderstorm date in the north and south areas wasn’t big.For the first thunderstorm date in the north and west of Fujian was early,and the final thunderstorm date was later,the thunderstorm activity time in the whole year was longer than that in the coast.They differed by nearly one month.[Conclusion] The research provided the scientific basis for the climate feasibility demonstration of major project items,provided the theory basis about the weather climate aspect for the thunder prevention and disaster reduction,and also laid the foundation for further studying the formation mechanism of thunderstorm in Fujian.展开更多
In this paper,we study a new numerical technique for a class of 2D nonlinear fractional diffusion-wave equations with the Caputo-type temporal derivative and Riesz-type spatial derivative.Galerkin finite element schem...In this paper,we study a new numerical technique for a class of 2D nonlinear fractional diffusion-wave equations with the Caputo-type temporal derivative and Riesz-type spatial derivative.Galerkin finite element scheme is used for the discretization in the spatial direction,and the temporal component is discretized by a new alternating direction implicit(ADI)method.Next,we strictly prove that the numerical method is stable and convergent.Finally,to confirm our theoretical analysis,some numerical examples in 2D space are presented.展开更多
While the threat of war has decreased, there have appeared intricate security issues that affect all aspects of human life, breaking through various defenses and threatening the well being of all actors in the contemp...While the threat of war has decreased, there have appeared intricate security issues that affect all aspects of human life, breaking through various defenses and threatening the well being of all actors in the contemporary world, including nations, groups and individuals. This risky situation calls for a new security concept, one that transcends traditional state centrism, national supremacy and coercion. The new security concept, which should assimilate the general theory of grand strategy,focuses on a vision that spans time and space, valuing humankind as it exists as one of the dynamic factors of nature and society. The essentials of the new security concept are to recognize balanced development as the substance of security and to govern national strength and the application of means and tactics. It aims at realizing comprehensive security across various social fields within states, to achieve mutual security among national, international and individual actors, as well as harmony between man and nature, continuous security leading to lasting and universal peace in the future.展开更多
Building a moderately prosperous society in all respects is a milestone in China’s human rights development.It clearly reflects the profound action logic of the CpC leading the Chinese people to fight for and realize...Building a moderately prosperous society in all respects is a milestone in China’s human rights development.It clearly reflects the profound action logic of the CpC leading the Chinese people to fight for and realize the protection of rights.At the level of values,the logic of rights for China’s human rights development is mainly manifested in four aspects:prioritizing the right to subsistence and the right to development in the rights system;importance given to citizenship and democracy by the goal of building a moderately prosperously society in all respects;advocating the right to unity and the right to participate in the common cause of the Chinese people;implementing the responsibility of leaders and managers to safeguard human rights.At the practical level,the protection logic of China’s human rights development mainly includes four links:firstly,gradual upgrading is a reliable procedure for the coordination of the human rights system;secondly,the rule of law is a solid foundation for the steady development of human rights;thirdly,the courage to explore is the important factor for the success of human rights practice;lastly,seeking common ground while shelving differences is the key consensus for mutual learning among human rights civilizations.In terms of time and space,China’s human rights development has achieved world-recognized success,laying a solid foundation for this endeavor to proceed,and providing experience and reference for people all over the world to pursue common human rights ideals.展开更多
NTS ( The network of time and space) is a new network that describes both the concept of time and the concept of space. This paper mainly illustrates the theory of NTS, the analysis of parameter, the chief characteris...NTS ( The network of time and space) is a new network that describes both the concept of time and the concept of space. This paper mainly illustrates the theory of NTS, the analysis of parameter, the chief characteristics and the application.展开更多
In the present paper,invariant subspace method has been extended for solving systems of multi-term fractional partial differential equations(FPDEs)involving both time and space fractional derivatives.Further,the metho...In the present paper,invariant subspace method has been extended for solving systems of multi-term fractional partial differential equations(FPDEs)involving both time and space fractional derivatives.Further,the method has also been employed for solving multi-term fractional PDEs in(1+n)dimensions.A diverse set of examples is solved to illustrate the method.展开更多
In many data stream mining applications, traditional density estimation methods such as kemel density estimation, reduced set density estimation can not be applied to the density estimation of data streams because of ...In many data stream mining applications, traditional density estimation methods such as kemel density estimation, reduced set density estimation can not be applied to the density estimation of data streams because of their high computational burden, processing time and intensive memory allocation requirement. In order to reduce the time and space complexity, a novel density estimation method Dm-KDE over data streams based on the proposed algorithm m-KDE which can be used to design a KDE estimator with the fixed number of kernel components for a dataset is proposed. In this method, Dm-KDE sequence entries are created by algorithm m-KDE instead of all kemels obtained from other density estimation methods. In order to further reduce the storage space, Dm-KDE sequence entries can be merged by calculating their KL divergences. Finally, the probability density functions over arbitrary time or entire time can be estimated through the obtained estimation model. In contrast to the state-of-the-art algorithm SOMKE, the distinctive advantage of the proposed algorithm Dm-KDE exists in that it can achieve the same accuracy with much less fixed number of kernel components such that it is suitable for the scenarios where higher on-line computation about the kernel density estimation over data streams is required. We compare Dm-KDE with SOMKE and M-kernel in terms of density estimation accuracy and running time for various stationary datasets. We also apply Dm-KDE to evolving data streams. Experimental results illustrate the effectiveness of the pro- posed method.展开更多
The charging load of electric vehicles(EVs)has a strong spatiotemporal randomness.Predicting the dynamic spatiotemporal distribution of the charging load of EVs is of great significance for the grid to cope with the a...The charging load of electric vehicles(EVs)has a strong spatiotemporal randomness.Predicting the dynamic spatiotemporal distribution of the charging load of EVs is of great significance for the grid to cope with the access of large-scale EVs.Existing studies lack a prediction model that can accurately describe the dual dynamic changes of EVs charging the load time and space.Therefore,a spatial-temporal dynamic load forecasting model,dilated causal convolution-2D neural network(DCC-2D),is proposed.First,a hole factor is added to the time dimension of the three-dimensional convolutional convolution kernel to form a two-dimensional hole convolution layer so that the model can learn the spatial dimension information.The entire network is then formed by stacking the layers,ensuring that the network can accept long-term historical input,enabling the model to learn time dimension information.The model is simulated with the actual data of the charging pile load in a certain area and compared with the ConvLSTM model.The results prove the validity of the proposed prediction model.展开更多
文摘Time and Space Thinking that is composed of time and space thinking is brought up in civil engineering. This paper makes a detailed analysis on application and role of time and space thinking in knowledge system and learning method of civil engineering and put forward time and space thinking to be similar with philosophical view of time and space. Time and space thinking is a scientific method, therefore, it is suggested to make students active in having such idea and strengthen students' understanding on time and space thinking, which will helping students recognize knowledge system and stimulate innovative abilities.
文摘The film The Hours is a masterpiece that reflects female spiritual predicament and it analyzes the life exploration and death struggle of three women in three periods deeply.This research chooses this film as material to study female self consciousness.In this paper,female self consciousness is discussed in two aspects,namely,from limitation and span of time and space aspect,and from the certain image in this film.At the end of this paper,there is a clear conclusion,namely a suggestion for female who is suffering from how to do self consciousness.
文摘A natural extension of the Lorentz transformation to its complex version was constructed together with a parallel extension of the Minkowski M<sup>4</sup> model for special relativity (SR) to complex C<sup>4</sup> space-time. As the [signed] absolute values of complex coordinates of the underlying motion’s characterization in C<sup>4</sup> one obtains a Newtonian-like type of motion whereas as the real parts of the complex motion’s description and of the complex Lorentz transformation, all the SR theory as modeled by M<sup>4</sup> real space-time can be recovered. This means all the SR theory is preserved in the real subspace M<sup>4</sup> of the space-time C<sup>4</sup> while becoming simpler and clearer in the new complex model’s framework. Since velocities in the complex model can be determined geometrically, with no primary use of time, time turns out to be definable within the equivalent theory of the reduced complex C<sup>4</sup> model to the C<sup>3</sup> “para-space” model. That procedure allows us to separate time from the (para)space and consider all the SR theory as a theory of C<sup>3</sup> alone. On the other hand, the complex time defined within the C<sup>3</sup> theory is interpreted and modeled by the single separate C<sup>1</sup> complex plane. The possibility for application of the C<sup>3</sup> model to quantum mechanics is suggested. As such, the model C<sup>3</sup> seems to have unifying abilities for application to different physical theories.
基金The work was supported partially by NSF ECS-0555394 and NIH/NIBIB EB004287.
文摘A high contrast to noise ratio(CNR)is always desirable for contrast-enhanced computed tomography angiography(CTA).To ensure a high CNR of the vascular images in CTA and potentially reduce the radiation exposure and contrast usage,an adaptive bolus chasing method is proposed and evaluated compared to the existing constant-speed method.The proposed method is based on a local time and space parameter varying model of the contrast bolus.Optimal scan time for the next segment of the vasculature is estimated and predicted in real time and guides the computed tomography(CT)scanner table movement that guarantees that each segment of the vasculature is scanned with the maximum possible enhancement.Simulations and experimental results show that the proposed bolus chasing method outperforms the conventional constant-speed method substantially.
文摘Orthogonal Time Frequency and Space(OTFS) modulation is expected to provide high-speed and ultra-reliable communications for emerging mobile applications, including low-orbit satellite communications. Using the Doppler frequency for positioning is a promising research direction on communication and navigation integration. To tackle the high Doppler frequency and low signal-to-noise ratio(SNR) in satellite communication, this paper proposes a Red and Blue Frequency Shift Discriminator(RBFSD) based on the pseudo-noise(PN) sequence.The paper derives that the cross-correlation function on the Doppler domain exhibits the characteristic of a Sinc function. Therefore, it applies modulation onto the Delay-Doppler domain using PN sequence and adjusts Doppler frequency estimation by red-shifting or blue-shifting. Simulation results show that the performance of Doppler frequency estimation is close to the Cramér-Rao Lower Bound when the SNR is greater than -15dB. The proposed algorithm is about 1/D times less complex than the existing PN pilot sequence algorithm, where D is the resolution of the fractional Doppler.
文摘Taking Sichuan Gymnasium Station as the research object, we explore land use characteristics over time of areas around Sichuan Gymnasium Station in terms of time. We extract the basic information of land use in areas around Sichuan Gymnasium Station in 2005, 2011, and 2016 through Google Earth in order to draw the map of land use status in three time nodes. We then analyze the degree of mixing and equilibrium, intensity of development of land, and land use patterns of areas around Sichuan Gymnasium Station with indexes including the area proportion of land use patterns, information entropy, and degree of equilibrium within a 1,000-m radius centered on the station, so as to reveal the spatial distribution characteristics of land around the station in different time nodes. Through comparative analysis, it is found that the development of rail transit has not significantly contributed to the boom of commerce and the development of the old city of Chengdu. We also analyze land use changes in areas around Sichuan Gymnasium Station in terms of space, and find that land use patterns in areas around commuter stations seem to be more complicated than that of the average station, and land use patterns in areas around Huaxiba Station and Nijiaqiao Station on Line 1, which opened first, are more complicated than that of Moziqiao Station and Yiguanmiao Station on Line 3. The original land use patterns formed in the old city often determine the selection of rail transit routes and rail transit stations. Adaptive stations do not play a decisive role in land use patterns in their surrounding areas, but have some impact on the plot ratio and building height of land for commercial use within the core area of the stations.
文摘With the development of productive forces. the space evolution of regional economicSystem keeps closer links with the traffic transport line. A kind of linear space regional scathetic bodyforms constantly and develops rapidly. Relying on the traffic trunk lines, it aggregates and diffusesconstantly.At the same time, it mixes population, industry, town, interflow of commodities, interflowof energy and interflow of information together.This unique space regional synthetic body is calledtraffic economic belt (TEB). In the paper, the basic concepts, types and qualities of TEB wereelaborated and the life-circle theory was put forward creatively.
基金Forestry Pest Control Project of Hubei Province(2019-308-001-010)。
文摘[Objectives]This study was conducted to accurately understand the spatial distribution of the outbreak of pine wood nematode disease,explore its spatial laws,and provide a more scientific and efficient analysis and decision-making basis for the prevention and management of pine wood nematode disease.[Methods]Taking the GIS management of Bursaphelenchus xylophilus tree felling in Yiling District as an example,the spatial positions of epidemic wood in the two years from 2019 to 2020 were collected.The spatial data management function of ArcGIS software was used to collect point and surface layers.Spatial information maps were drawn by spatial visualization,trend surface,spatial autocorrelation,nearest neighbor distance index and spatial-temporal clustering analysis of kernel density,so as to intuitively understand the evolution of spatial pattern trend of pine wood nematode disease,and to explain the variation raw and diffusion characteristics of pine wood nematode disease.[Results](1)Under the control measures,the affected pine forests and epidemic sites(subcompartments)decreased in the following year,the spread of the epidemic was still spreading,which was spreading from the central to the western and northern regions.The distribution of the plane epidemic sites was sparse from high concentration.The new epidemic sites occurred in a jump,and the number of affected pine trees was high.The outbreak was concentrated in a certain area,and the risk was high.The natural transmission and diffusion would coexist for a long time.(2)The epidemic trend of pine nematode in the two years was in the east and west,with a high value in the east,and the trend line was almost straight line.The outbreak of pine nematode showed cone-shaped central point aggregation and spread.(3)The spatial and temporal clustering characteristics of the epidemic show spatial clustering in the overall pattern,high clustering of pine victims caused by the spread of the epidemic source and clustering distribution pattern of epidemic points.(4)In the two years,the damaged pine trees were searched within the range of 5 km by using the distance threshold.The kernel density maps showed that the damaged pine trees in 2019 were more serious than those in 2020.The result of density map was consistent with the nearest neighbor distance index,and the damaged pine forests were mainly concentrated.(5)The epidemic situation of B.xylophilus disease in this region has a certain number of epidemic sites and a wide distribution area,the epidemic situation is difficult to eradicate in a short time.On the comprehensive measures,we should increase the clearing of epidemic trees,block the spread of the epidemic situation in the new areas,reduce the epidemic sites,regulate the density of pine trees by forest management,reduce the density of Monochamus alternatus and establish a broad-leaved forest ecosystem.[Conclusions]The study provides assistive technology support for the prevention and control of pine wood nematode disease.
文摘The objective of this paper is to utilize images of spatial and temporal fluctuations of temperature over the Earth to study the global climate variation. We illustrated that monthly temperature observations from weather stations could be decomposed as components with different time scales based on their spectral distribution. Kolmogorov-Zurbenko (KZ) filters were applied to smooth and interpolate gridded temperature data to construct global maps for long-term (≥ 6 years) trends and El Nino-like (2 to 5 years) movements over the time period of 1893 to 2008. Annual temperature seasonality, latitude and altitude effects have been carefully accounted for to capture meaningful spatiotemporal patterns of climate variability. The result revealed striking facts about global temperature anomalies for specific regions. Correlation analysis and the movie of thermal maps for El Nino-like component clearly supported the existence of such climate fluctuations in time and space.
基金supported by the National Natural Science Foundation of China (Grant No. U1304618)the Open Fund of Key Laboratory of Precision Navigation and Timing Technology of Chinese Academy of Sciences(Grant No. 2012PNTT01)+5 种基金the Postdoctoral Grant of China (Grant Nos. 2011M501446, 2012T50798)the Basic and Advanced Technology Research Foundation of Henan Province under Grant (Grant No. 122300410169)The Key Science and Technology Foundation of Henan Province under Grant (Grant No. 132102210180)the Doctor Fund of Zhengzhou University of Light Industry under (Grant No. 2011BSJJ031)the Scientific Research Fund of Zhengzhou University of Light Industry under (Grant No. 2012XJJ009)the Fundamental Research Funds for the Central Universities(Grant No. K5051204003)
文摘According to the time&space conversion relations and different frequency phase detection principle,an ultra-high precision time&frequency measurement method is proposed in this paper.The higher accuracy and stability of the speed of light and electromagnetic signals during the transmission in space or a specific medium enable the measurement of short time interval which uses the coincidence detection of signal’s transmission delay in length.The measurement precision better than 10 picoseconds can be easily obtained.The method develops the length vernier utilizing the stability of signal’s transmission delay,minimizes the fuzzy region of phase coincidence between the standard frequency signal and the measured signal,approaches the best phase coincidences and therefore improves the measurement precision which is higher than the precision provided by the traditional methods based on frequency processing.Besides,the method costs less than the traditional methods and can also solve the problem of the measurement of super-high frequency.Experimental results show the method can improve the measurement precision to 10 12/s in the time&frequency domain.
基金supported by Project of Plan for Science and Technology Development of Jilin Province (No. 20101504)Project of Research of Science and Technology for the 11th Five-year Plan of Jilin Education Department (No. 2009604)
文摘A Bloom filter is a space-efficient data structure used for concisely representing a set as well as membership queries at the expense of introducing false positive. In this paper, we propose the L-priorities Bloom filter (LPBF) as a new member of the Bloom filter (BF) family, it uses a limited multidimensional bit space matrix to replace the bit vector of standard bloom filters in order to support different priorities for the elements of a set. We demonstrate the time and space complexity, especially the false positive rate of LPBF. Furthermore, we also present a detailed practical evaluation of the false positive rate achieved by LPBF. The results show that LPBF performs better than standard BFs with respect to false positive rate.
文摘[Objective] The research aimed to study the activity characteristics and climate rule of thunderstorm in Fujian Province.[Method] Based on the daily thunderstorm data in 67 meteorological stations of Fujian Province during 1960-2007,the spatial and temporal distribution characteristics of thunderstorm in Fujian Province were analyzed by using the climate tendency rate,the trend coefficient and so on.[Result] The distribution of thunderstorm days showed the northeast-southwest direction and increased gradually from the coast to the inland in Fujian Province during 1960-2007.The high value zone was in Longyan,and the thunderstorm days in the coastal islands were the fewest.The thunderstorm days had the obvious decrease trend in Fujian Province in 48 years.The decrease speeds in the central coastal area and most of inland mountain area were 3.5 and 4.5 d/10 a.The decrease speed was 5.5 d/10 a in the north of Ningde,the east of Sanming and some areas in Nanping.The trend coefficient variation of thunderstorm days had the obvious regional characteristic.Especially the decrease trend in the inland mountain area was more obvious than that in the coast.The decrease of thunderstorm day trend coefficient in the north of Nanping was the most,and the trend coefficient was-0.65.But the decrease trend in the central coastal area wasn’t obvious,and the coefficient was only-0.15.The thunderstorm day had the obvious seasonal variation.The multi-occurrence period of thunderstorm was during March-september and reached the maximum value in August.Started from September,the thunderstorm quickly decreased.From October to February in next year,the thunderstorm happened seldom.The average first thunderstorm date in the northwest area was earlier than that in the southeast area.The difference of average final thunderstorm date in the north and south areas wasn’t big.For the first thunderstorm date in the north and west of Fujian was early,and the final thunderstorm date was later,the thunderstorm activity time in the whole year was longer than that in the coast.They differed by nearly one month.[Conclusion] The research provided the scientific basis for the climate feasibility demonstration of major project items,provided the theory basis about the weather climate aspect for the thunder prevention and disaster reduction,and also laid the foundation for further studying the formation mechanism of thunderstorm in Fujian.
基金NSF of China[grant number:11371157]Natural Science Foundation of Anhui Higher Education Institutions of China[grant number:KJ2016A492]Natural Science Foundation of Bozhou College[grant number:BSKY201426,BSKY201535].
文摘In this paper,we study a new numerical technique for a class of 2D nonlinear fractional diffusion-wave equations with the Caputo-type temporal derivative and Riesz-type spatial derivative.Galerkin finite element scheme is used for the discretization in the spatial direction,and the temporal component is discretized by a new alternating direction implicit(ADI)method.Next,we strictly prove that the numerical method is stable and convergent.Finally,to confirm our theoretical analysis,some numerical examples in 2D space are presented.
文摘While the threat of war has decreased, there have appeared intricate security issues that affect all aspects of human life, breaking through various defenses and threatening the well being of all actors in the contemporary world, including nations, groups and individuals. This risky situation calls for a new security concept, one that transcends traditional state centrism, national supremacy and coercion. The new security concept, which should assimilate the general theory of grand strategy,focuses on a vision that spans time and space, valuing humankind as it exists as one of the dynamic factors of nature and society. The essentials of the new security concept are to recognize balanced development as the substance of security and to govern national strength and the application of means and tactics. It aims at realizing comprehensive security across various social fields within states, to achieve mutual security among national, international and individual actors, as well as harmony between man and nature, continuous security leading to lasting and universal peace in the future.
基金the key project“Research on the Mechanism of Enhancing China’s Right of Speech in International Law Oriented by of National Image”of The National Social Science Fund of China(19AFX024)
文摘Building a moderately prosperous society in all respects is a milestone in China’s human rights development.It clearly reflects the profound action logic of the CpC leading the Chinese people to fight for and realize the protection of rights.At the level of values,the logic of rights for China’s human rights development is mainly manifested in four aspects:prioritizing the right to subsistence and the right to development in the rights system;importance given to citizenship and democracy by the goal of building a moderately prosperously society in all respects;advocating the right to unity and the right to participate in the common cause of the Chinese people;implementing the responsibility of leaders and managers to safeguard human rights.At the practical level,the protection logic of China’s human rights development mainly includes four links:firstly,gradual upgrading is a reliable procedure for the coordination of the human rights system;secondly,the rule of law is a solid foundation for the steady development of human rights;thirdly,the courage to explore is the important factor for the success of human rights practice;lastly,seeking common ground while shelving differences is the key consensus for mutual learning among human rights civilizations.In terms of time and space,China’s human rights development has achieved world-recognized success,laying a solid foundation for this endeavor to proceed,and providing experience and reference for people all over the world to pursue common human rights ideals.
文摘NTS ( The network of time and space) is a new network that describes both the concept of time and the concept of space. This paper mainly illustrates the theory of NTS, the analysis of parameter, the chief characteristics and the application.
文摘In the present paper,invariant subspace method has been extended for solving systems of multi-term fractional partial differential equations(FPDEs)involving both time and space fractional derivatives.Further,the method has also been employed for solving multi-term fractional PDEs in(1+n)dimensions.A diverse set of examples is solved to illustrate the method.
基金This work was supported in part by the National Natural Science Foundation of China (Grants Nos. 61170122, 61272210), by Japan Society for the Promotion of Sciences (JSPS), by the Natural Science Foundation of Jiangsu Province (BK2011417, BK2011003), by Jiangsu 333 Expert Engineering Grant (BRA201114-2), and by 2011 and 2012 Postgraduate Student's Creative Research Funds of Jiangsu Province (CXZZ11-0483, CXZZ12-0759).
文摘In many data stream mining applications, traditional density estimation methods such as kemel density estimation, reduced set density estimation can not be applied to the density estimation of data streams because of their high computational burden, processing time and intensive memory allocation requirement. In order to reduce the time and space complexity, a novel density estimation method Dm-KDE over data streams based on the proposed algorithm m-KDE which can be used to design a KDE estimator with the fixed number of kernel components for a dataset is proposed. In this method, Dm-KDE sequence entries are created by algorithm m-KDE instead of all kemels obtained from other density estimation methods. In order to further reduce the storage space, Dm-KDE sequence entries can be merged by calculating their KL divergences. Finally, the probability density functions over arbitrary time or entire time can be estimated through the obtained estimation model. In contrast to the state-of-the-art algorithm SOMKE, the distinctive advantage of the proposed algorithm Dm-KDE exists in that it can achieve the same accuracy with much less fixed number of kernel components such that it is suitable for the scenarios where higher on-line computation about the kernel density estimation over data streams is required. We compare Dm-KDE with SOMKE and M-kernel in terms of density estimation accuracy and running time for various stationary datasets. We also apply Dm-KDE to evolving data streams. Experimental results illustrate the effectiveness of the pro- posed method.
基金Supported by the Research Foundation of Education Bureau of Hunan Province(20A021)National Natural Science Foundation of China(51777015).
文摘The charging load of electric vehicles(EVs)has a strong spatiotemporal randomness.Predicting the dynamic spatiotemporal distribution of the charging load of EVs is of great significance for the grid to cope with the access of large-scale EVs.Existing studies lack a prediction model that can accurately describe the dual dynamic changes of EVs charging the load time and space.Therefore,a spatial-temporal dynamic load forecasting model,dilated causal convolution-2D neural network(DCC-2D),is proposed.First,a hole factor is added to the time dimension of the three-dimensional convolutional convolution kernel to form a two-dimensional hole convolution layer so that the model can learn the spatial dimension information.The entire network is then formed by stacking the layers,ensuring that the network can accept long-term historical input,enabling the model to learn time dimension information.The model is simulated with the actual data of the charging pile load in a certain area and compared with the ConvLSTM model.The results prove the validity of the proposed prediction model.