Vegetation plays a key role in improving wind environment of residential districts,and is helpful for creating a comfortable and beautiful living environment.The optimal design of vegetation for wind environment impro...Vegetation plays a key role in improving wind environment of residential districts,and is helpful for creating a comfortable and beautiful living environment.The optimal design of vegetation for wind environment improvement in winter was investigated by carrying out field experiments in Heqingyuan residential area in Beijing,and after that,numerical simulation with SPOTE(simulation platform for outdoor thermal environment) experiments for outdoor thermal environment of vegetation was adopted for comparison.The conclusions were summarized as follows:1) By comparing the experimental data with simulation results,it could be concluded that the wind field simulated was consistent with the actual wind field,and the flow distribution impacted by vegetation could be accurately reflected;2) The wind velocity with vegetation was lower than that without vegetation,and the wind velocity was reduced by 46%;3) By adjusting arrangement and types of vegetation in the regions with excessively large wind velocity,the pedestrian-level wind velocity could be obviously improved through the simulation and comparison.展开更多
There are many experimental approaches,field investigations and numerical calculations for movements of woods in a clear water and debris flow.However,kinematic conditions for accumulated logs and the interactions bet...There are many experimental approaches,field investigations and numerical calculations for movements of woods in a clear water and debris flow.However,kinematic conditions for accumulated logs and the interactions between a main flow and logs have not been fully evaluated.Mitigations for woods need taking into account the characteristics of tree species such as conifer and broad-leaf trees and of shapes such as root swells and crown.In the present study,we focus on the differences in specific weight of conifer and broad-leaf trees with some moisture in a sediment-water mixture flow with narrow flow width,and consider that conifer and broad-leaf tree are floating and submerged solid phase,respectively.Flume tests are conducted in steady flow of clear and debris flow over a rigid bed in order to evaluate conifer and broad-leaf tree movement in clear water and debris flow.Experimental data indicates that dimensionless transverse diffusion coefficient can be 0.1 to 0.4 and 0.3 to 0.9 in flow direction.Those diffusive characteristics seem to be independent of Reynolds number and Froude number,but dependent of bed slope,i.e.,gravity,though detailed considerations are needed to discuss about flow characteristics such as spatial eddy structures,momentum transfer induced by interactions of logs and so on.展开更多
The turbidity maximum zone(TMZ) is one of the most important regions in an estuary.However,the high concentration of suspended material makes it difficult to measure the partial pressure of CO_2(pCO_2) in these region...The turbidity maximum zone(TMZ) is one of the most important regions in an estuary.However,the high concentration of suspended material makes it difficult to measure the partial pressure of CO_2(pCO_2) in these regions.Therefore,very little data is available on the pCO_2 levels in TMZs.To relatively accurately evaluate the CO_2 flux in an example estuary,we studied the TMZ and surrounding area in the Changjiang(Yangtze) River estuary.From seasonal cruises during February,August,November 2010,and May 2012,the pCO_2 in the TMZ and surrounding area was calculated from pH and total alkalinity(TA)measured in situ,from which the CO_2 flux was calculated.Overall,the TMZ and surrounding area acted as a source of atmosphere CO_2 in February and November,and as a sink in May and August.The average FCO_2was-9,-16,5,and 5 mmol/(m^2·d) in May,August,November,and February,respectively.The TMZ's role as a source or sink of atmosphere CO_2 was quite different to the outer estuary.In the TMZ and surrounding area,suspended matter,phytoplankton,and pH were the main factors controlling the FCO_2,but here the influence of temperature,salinity,and total alkalinity on the FCO_2 was weak.Organic carbon decomposition in suspended matter was the main reason for the region acting as a CO_2 source in winter,and phytoplankton production was the main reason the region was a CO_2 sink in summer.展开更多
As a case study of the Panji No.1 Coal Mine in Anhui Province, based on thesite measured and statistical data, summarized the lithologic associations, characteristicsand distribution laws of interlayer-gliding structu...As a case study of the Panji No.1 Coal Mine in Anhui Province, based on thesite measured and statistical data, summarized the lithologic associations, characteristicsand distribution laws of interlayer-gliding structures and tectonic coal in the No.11-2 coalseams.The results show that 9 modes of lithologic association can form interlayer-glidingstructures.It is more easy for rock slip to occur when the lithologic associations are mainroof + coal seam + immediate floor type, compound roof+immediate roof + coal seam +immediate floor type and immediate roof + coal seam + immediate floor type.Lithologicassociations of roof and floor are the precondition to the formation of interlayer-glidingstructures.展开更多
The elevated supersaturation of total dissolved gas (TDG) downstream of a high-dam spill has deleterious effects on fish in a large range. A one-dimensional (l-D) longitudinal model is optimal for the prediction o...The elevated supersaturation of total dissolved gas (TDG) downstream of a high-dam spill has deleterious effects on fish in a large range. A one-dimensional (l-D) longitudinal model is optimal for the prediction of supersaturated TDG dissipation over a long distance. The key issue of the model is to determine the dissipation coefficient accurately. In agreement with field observations and experiment data, dimensional analysis and regression were performed to propose a formula for estimating the dissipation coefficient of supersaturated TDG in various rivers and reservoirs, and it involves the effects of the turbulence intensity, the hydro-pressure and the solid-liquid interface. The friction velocity, water depth, hydraulic radius and Froude number are independent variables in the formula which are easy to determine in practical applications. The 1-D longitudinal model is implemented to calculate the dissipation of TDG in a reach of the Jinsha River. Good agreement is found between the calculated results and field data for both the dissipation coefficient and the dissipation process.展开更多
Regional Landslide Susceptibility Zonation(LSZ) is always challenged by the available amount of field data, especially in southwestern China where large mountainous areas and limited field information coincide. Statis...Regional Landslide Susceptibility Zonation(LSZ) is always challenged by the available amount of field data, especially in southwestern China where large mountainous areas and limited field information coincide. Statistical learning algorithms are believed to be superior to traditional statistical algorithms for their data adaptability. The aim of the paper is to evaluate how statistical learning algorithms perform on regional LSZ with limited field data. The focus is on three statistical learning algorithms, Logistic Regression(LR), Artificial Neural Networks(ANN) and Support Vector Machine(SVM). Hanzhong city, a landslide prone area in southwestern China is taken as a study case. Nine environmental factors are selected as inputs. The accuracies of the resulting LSZ maps are evaluated through landslide density analysis(LDA), receiver operating characteristic(ROC) curves and Kappa index statistics. The dependence of the algorithm on the size of field samples is examined by varying the sizes of the training set. The SVM has proven to be the most accurate and the most stable algorithm at small training set sizes and on all known landslide sizes. The accuracy of SVM shows a steadilyincreasing trend and reaches a high level at a small size of the training set, while accuracies of LR and ANN algorithms show distinct fluctuations. The geomorphological interpretations confirm the strength of SVM on all landslide sizes. Our results show that the strengths of SVM in generalization capability and model robustness make it an appropriate and efficient tool for regional LSZ with limited landslide field samples.展开更多
The process and characteristics of loading on high-speed railway bridge pile foundation were firstly obtained by means of field research and analysis,and the corresponding loading function was presented.One-dimensiona...The process and characteristics of loading on high-speed railway bridge pile foundation were firstly obtained by means of field research and analysis,and the corresponding loading function was presented.One-dimensional consolidation equation of elastic multilayered soils was then established with single drainage or double drainages under multilevel loading.Moreover,the formulas for calculating effective stress and settlement were derived from the Laplace numerical inversion transform.The three-dimensional composite analysis method of bridge pile group was improved,where the actual load conditions of pile foundation could be simulated,and the consolidation characteristics of soil layers beneath pile were also taken into account.Eventually,a corresponding program named LTPGS was developed to improve the calculation efficiency.The comparison between long-term settlement obtained from the proposed method and the in-situ measurements of pile foundation was illustrated,and a close agreement is obtained.The error between computed and measured results is less than 1 mm,and it gradually reduces with time.It is shown that the proposed method can effectively simulate the long-term settlement of pile foundation and program LTPGS can provide a reliable estimation.展开更多
Large-scale field shear tests on ten specimens of the red-sandstone embankment at a highway in Hunan,China,were performed to examine mechanical characteristics and parameters of red-sandstone.The curves of thrust-disp...Large-scale field shear tests on ten specimens of the red-sandstone embankment at a highway in Hunan,China,were performed to examine mechanical characteristics and parameters of red-sandstone.The curves of thrust-displacement,failure mode,and shear strength parameters for red-sandstone with different water contents,different compactions,and different grain size distributions were obtained from the tests.A practical procedure of in-situ test for red-sandstone embankment was proposed to normalize the test equipment and test steps.Based on three-dimensional thrust-sliding limit equilibrium method,the formulas for calculating strength parameters of red-sandstone considering three-dimensional sliding surface were inferred.The results show that red-sandstone has typical complete curves of stress-strain,strain softening,which are caused by the special structure of red-sandstone;water content and compaction are important factors for strength and failure mode of red-sandstone;The average value of cohesion and internal friction angle of the specimens calculated by three-dimensional technique are 21.56 kPa and 29.29°,respectively,and those by traditional two-dimensional method are 25.52 kPa and 33.76°,respectively.展开更多
A new type of pit supporting structure, which was tested and verified using the sensor monitoring technology, was presented. The new supporting structure is assembled by prefabricated steel structural units. The adjac...A new type of pit supporting structure, which was tested and verified using the sensor monitoring technology, was presented. The new supporting structure is assembled by prefabricated steel structural units. The adjacent steel structural units are jointed with fasteners, and each steel structural unit has a certain radian and is welded by two steel tubes and one piece of steel disc. In order to test and verify the reliability of the new supporting structure, the field tests are designed. The main monitoring programs include the hoop stress of supporting structure, lateral earth pressure, and soil deformation. The monitoring data of the field tests show that the new supporting structure is convenient, reliable and safe.展开更多
ERT(electrical resistance tomography) is effective method for visualization of multiphase flows,offering some advantages of rapid response and low cost,so as to explore the transient hydrodynamics.Aiming at this targe...ERT(electrical resistance tomography) is effective method for visualization of multiphase flows,offering some advantages of rapid response and low cost,so as to explore the transient hydrodynamics.Aiming at this target,a fully programmable and reconfigurable FPGA(field programmable gate array)-based Compact PCI(peripheral component interconnect) bus linked sixteen-channel ERT system has been presented.The data acquisition system is carefully designed with function modules of signal generator module;Compact PCI transmission module and data processing module(including data sampling,filtering and demodulating).The processing module incorporates a powerful FPGA with Compact PCI bus for communication,and the measurement process management is conducted in FPGA.Image reconstruction algorithms with different speed and accuracy are also coded for this system.The system has been demonstrated in real time(1400 frames per second for 50 kHz excitation) with signal-noise-ratio above 62 dB and repeatability error below 0.7%.Static experiments have been conducted and the images manifested good resolution relative to the actual object distribution.The parallel ERT system has provided alternative experimental platform for the multiphase flow measurements by the dynamic experiments in terms of concentration and velocity.展开更多
It has been 30 years since the family planning policy had been implemented in the last 1970s. Today, the first generation of only child has already reached thirties and their parents have entered into old age so that ...It has been 30 years since the family planning policy had been implemented in the last 1970s. Today, the first generation of only child has already reached thirties and their parents have entered into old age so that they may confront such a dilemma situation in which they should not only look after their own child but also take care of their parents. The paper find the different demand of the aging people in different type of family through the site investigation about pension service demand in three different kinds of communities in Cao Hejing. The survey mainly make a statistical analysis in economic situation, life care and emotional solace through the on-site questionnaire and interview, finding the particularity of the only child family, sorting out the best pension service strategy for the one-child family through the analysis research and the reference of international practice.展开更多
A survey to identify constraints and design strategies to improve the camel milk and meat value chains was conducted in northern Kenya using Participatory Integrated Community Development (PICD), Focus Group Discuss...A survey to identify constraints and design strategies to improve the camel milk and meat value chains was conducted in northern Kenya using Participatory Integrated Community Development (PICD), Focus Group Discussions (FGD), among other methods. In a second step, field testing of an intervention on milk and meat hygiene was carried out at household level. Survey results indicated that about 50% of marketable camel milk was not sold, 30% of marketed camel milk per annum was sold in sour state at US$ 0.13 lower that the price of a litre of fresh milk while processed meat got spoiled along the chain. Annual economic losses associated with milk spoilage were estimated at US$ 961,538.5. Preliminary findings of the field testing indicated that an additional 3 million litres of camel milk was sold in fresh state, giving an annual saving of US$ 384,615.4. Increased profitability of up to 60% compared to 30% before the intervention was reported among nyirinyiri processors. In conclusion, economic potential of the camel could be fully exploited by facilitating adoption of interventions such as hygiene, among others at all levels of the camel milk and meat value chains.展开更多
A reasonable unsupported roof distance(URD) when advancing underground coal mine roadways can contribute greatly to safe and rapid roadway development.A mechanical model of the roof,using the relationship between the ...A reasonable unsupported roof distance(URD) when advancing underground coal mine roadways can contribute greatly to safe and rapid roadway development.A mechanical model of the roof,using the relationship between the roof stress distribution and URD,obtained by the difference method,and roof stability according to the in-situ roof stress and rock mass strength was developed.We subsequently designed a proper range of URD,developed a testing method of URD with the function of mining protection,evaluated roof stability through analyzing the test data and then determined a reasonable URD.Considering the factors of the geological conditions,the immediate roof stability and the efficiency of the labor arrangement system,the URD of the advancing roadway of 9802 working face in Zhangshuanglou coal mine was determined to be 6 m using the proposed method.The results show that,when a 2 m length of roadway was reinforced by temporary support and high pre-stressed bolt support after the roadway advancement of 6 m per cycle,the speed and the security of the roadway development can be achieved and the advance rate can reach more than 400 m per month.展开更多
The tourism consumption behavior of the young people has significant effect on the present social tourism consumption behavior. Intensifying the research on tourism consumption behavior of the youth group helps to exp...The tourism consumption behavior of the young people has significant effect on the present social tourism consumption behavior. Intensifying the research on tourism consumption behavior of the youth group helps to explore the hot spot of tourism consumption, and designing specific marketing programs and taping into consumption potential is the key to market development. The research takes the university students in the youth group as an example to analyze the features and difference of tourism consumption behavior and observe tourism consumption marketing of the university students, for providing reference for the expansion of tourism market.展开更多
The design, manufacture and deployment of embedded systems become increasingly complex and multidisciplinary process. Before the steps of manufacturing and deployment, a simulation and validation phase is necessary. I...The design, manufacture and deployment of embedded systems become increasingly complex and multidisciplinary process. Before the steps of manufacturing and deployment, a simulation and validation phase is necessary. In this paper, a WSN (wireless sensors network) emulator, implemented on a FPGA, is described by: describing some models as examples, how multiple simulations can be done when the device was configured and programmed once, and how results from the behavioral emulator can be extracted. The diversity of applications and the typically scarce node resources set very tight constraints to WSN. It is not possible to fulfill all requirements with a general purpose WSN, for which reason the rapid development of application specific WSNs is preferred. A new emulator for the design, simulation, and evaluation of WSNs, implemented on a very dense FPGA (field programmable gate arrays), is presented, exploring the parallelism and his resources to do a very rapid simulation ofa WSN for long periods, and without overloading memory by the intermediate data.展开更多
The paper analyze and design and implement a remote control system based on embedded web server network. A computer network remote control system mainly includes server, client and the control information. Server regi...The paper analyze and design and implement a remote control system based on embedded web server network. A computer network remote control system mainly includes server, client and the control information. Server registration information realize the user command; client provides network hardware, software and other system resources, the system response message and then feedback service instruction. The research results show that, the embedded web server can be assigned to the field device user information through the browser, field device data also can access to the browser through the web server. In order to achieve remote monitoring, control, diagnostics and configuration of the equipment.展开更多
This paper examines the impacts of market-oriented electricity reform on macroeconomic variables. It develops an ad hoc econometric model for this purpose, using a panel data of 19 developed countries plus seven Austr...This paper examines the impacts of market-oriented electricity reform on macroeconomic variables. It develops an ad hoc econometric model for this purpose, using a panel data of 19 developed countries plus seven Australian States for the period of 1970-2008. Significance of the impacts is firstly tested against three distinct institutional features of electricity reform, namely: (1) organizational restructuring (i.e., functional unbundling of traditionally vertically integrated industry); (2) market restructuring (introduction of mandatory bid-based spot market); and (3) privatization. The extents of the impacts are, then, quantified in terms of relative contribution of such institutional changes to aggregate output growth in short-run, medium-run and long-run. The results reveal that only functional unbundling has made significant contribution to output growth. The results, further, specify that functional unbundling has made, on average, an additional 0.06% and 2.7% contribution to output growth rate in medium-run and long-run respectively.展开更多
The paper deals with the comparison of three different digital devices used for the computing of permanent magnet synchronous motor (PMSM) model. Model is used for virtual high frequency injection method (VHFIM) s...The paper deals with the comparison of three different digital devices used for the computing of permanent magnet synchronous motor (PMSM) model. Model is used for virtual high frequency injection method (VHFIM) sensorless control, where injection and acting voltages are virtual ones. For computing the whole PMSM model, differential equations are used. The paper is focused on performance analysis of computing speed and accuracy of field-programmable gate array (FPGA) device, digital signal controller and Power PC microcontroller and results are compared.展开更多
High-precision(±0.1 ppm) and high-frequency(hourly averaged) in situ measurements of atmospheric carbon dioxide(CO2) were made for the first time from August 2005 to July 2007 at Yanbian,China using a non-dispers...High-precision(±0.1 ppm) and high-frequency(hourly averaged) in situ measurements of atmospheric carbon dioxide(CO2) were made for the first time from August 2005 to July 2007 at Yanbian,China using a non-dispersive Infrared(NDIR) analyzer with National Oceanic and Atmospheric Administration/Earth System Research Laboratory(NOAA/ESRL) standards.The results of these measurements are presented in this paper and are used to investigate the regional representativeness of regional background data at Yanbian and determine the CO2 emission source regions in Northeast Asia.The phase of the monthly variations at Yanbian reflects the special regional characteristics,which were overall in excellent agreement with other observatories in the middle-to-high latitudes in the Northern Hemisphere.Applying a hybrid receptor model to the regional emission source events in cold period(November-April),we estimated the distribution of the major CO2 emissions in the northeast Asia.The results indicated that the strongest potential emission areas contributing to Yanbian are the Beijing & Tianjin metropolitan areas,southwestern part of Shandong Province including Jinan,and Vladivostok.The results of this study reveal the usefulness of in situ CO2 measurements at Yanbian in establishing the scientific foundation for monitoring the large CO2 emission areas in northern China and Russia.Continued monitoring of CO2 at Yanbian within a regional network should provide significant contributions to both understanding the global/regional carbon cycle and constraining "top-down" emissions in Northeast Asia.展开更多
基金Project(50878111) supported by the National Natural Science Foundation of China
文摘Vegetation plays a key role in improving wind environment of residential districts,and is helpful for creating a comfortable and beautiful living environment.The optimal design of vegetation for wind environment improvement in winter was investigated by carrying out field experiments in Heqingyuan residential area in Beijing,and after that,numerical simulation with SPOTE(simulation platform for outdoor thermal environment) experiments for outdoor thermal environment of vegetation was adopted for comparison.The conclusions were summarized as follows:1) By comparing the experimental data with simulation results,it could be concluded that the wind field simulated was consistent with the actual wind field,and the flow distribution impacted by vegetation could be accurately reflected;2) The wind velocity with vegetation was lower than that without vegetation,and the wind velocity was reduced by 46%;3) By adjusting arrangement and types of vegetation in the regions with excessively large wind velocity,the pedestrian-level wind velocity could be obviously improved through the simulation and comparison.
基金supported by Research Budget from Research and Development Center,NIPPON KOEI Co.,Ltd (Research theme:Modeling for debris flow with woods and their applicability)
文摘There are many experimental approaches,field investigations and numerical calculations for movements of woods in a clear water and debris flow.However,kinematic conditions for accumulated logs and the interactions between a main flow and logs have not been fully evaluated.Mitigations for woods need taking into account the characteristics of tree species such as conifer and broad-leaf trees and of shapes such as root swells and crown.In the present study,we focus on the differences in specific weight of conifer and broad-leaf trees with some moisture in a sediment-water mixture flow with narrow flow width,and consider that conifer and broad-leaf tree are floating and submerged solid phase,respectively.Flume tests are conducted in steady flow of clear and debris flow over a rigid bed in order to evaluate conifer and broad-leaf tree movement in clear water and debris flow.Experimental data indicates that dimensionless transverse diffusion coefficient can be 0.1 to 0.4 and 0.3 to 0.9 in flow direction.Those diffusive characteristics seem to be independent of Reynolds number and Froude number,but dependent of bed slope,i.e.,gravity,though detailed considerations are needed to discuss about flow characteristics such as spatial eddy structures,momentum transfer induced by interactions of logs and so on.
基金Supported by the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA05030402)the National Natural Science Foundation of China(Nos.U1406403,41121064,41376092)the Public Science and Technology Research Funds Projects of Ocean(No.200905012-9)
文摘The turbidity maximum zone(TMZ) is one of the most important regions in an estuary.However,the high concentration of suspended material makes it difficult to measure the partial pressure of CO_2(pCO_2) in these regions.Therefore,very little data is available on the pCO_2 levels in TMZs.To relatively accurately evaluate the CO_2 flux in an example estuary,we studied the TMZ and surrounding area in the Changjiang(Yangtze) River estuary.From seasonal cruises during February,August,November 2010,and May 2012,the pCO_2 in the TMZ and surrounding area was calculated from pH and total alkalinity(TA)measured in situ,from which the CO_2 flux was calculated.Overall,the TMZ and surrounding area acted as a source of atmosphere CO_2 in February and November,and as a sink in May and August.The average FCO_2was-9,-16,5,and 5 mmol/(m^2·d) in May,August,November,and February,respectively.The TMZ's role as a source or sink of atmosphere CO_2 was quite different to the outer estuary.In the TMZ and surrounding area,suspended matter,phytoplankton,and pH were the main factors controlling the FCO_2,but here the influence of temperature,salinity,and total alkalinity on the FCO_2 was weak.Organic carbon decomposition in suspended matter was the main reason for the region acting as a CO_2 source in winter,and phytoplankton production was the main reason the region was a CO_2 sink in summer.
基金Supported by the National Natural Science Foundation of China(40772092)
文摘As a case study of the Panji No.1 Coal Mine in Anhui Province, based on thesite measured and statistical data, summarized the lithologic associations, characteristicsand distribution laws of interlayer-gliding structures and tectonic coal in the No.11-2 coalseams.The results show that 9 modes of lithologic association can form interlayer-glidingstructures.It is more easy for rock slip to occur when the lithologic associations are mainroof + coal seam + immediate floor type, compound roof+immediate roof + coal seam +immediate floor type and immediate roof + coal seam + immediate floor type.Lithologicassociations of roof and floor are the precondition to the formation of interlayer-glidingstructures.
基金Projects(51179111,51279115)supported by the National Natural Science Foundation of ChinaProject(20110181110073)supported by the Doctoral Programs Foundation of Ministry of Education of China
文摘The elevated supersaturation of total dissolved gas (TDG) downstream of a high-dam spill has deleterious effects on fish in a large range. A one-dimensional (l-D) longitudinal model is optimal for the prediction of supersaturated TDG dissipation over a long distance. The key issue of the model is to determine the dissipation coefficient accurately. In agreement with field observations and experiment data, dimensional analysis and regression were performed to propose a formula for estimating the dissipation coefficient of supersaturated TDG in various rivers and reservoirs, and it involves the effects of the turbulence intensity, the hydro-pressure and the solid-liquid interface. The friction velocity, water depth, hydraulic radius and Froude number are independent variables in the formula which are easy to determine in practical applications. The 1-D longitudinal model is implemented to calculate the dissipation of TDG in a reach of the Jinsha River. Good agreement is found between the calculated results and field data for both the dissipation coefficient and the dissipation process.
基金supported by the open fund of Key Laboratory of Geoscience Spatial Information Technology, Ministry of Land and Resource of the China (Grant No. KLGSIT2013-15)The GIS-studio (www.gis-studio.nl) of the Institute for Biodiversity and Ecosystem Dynamics (IBED) is acknowledged for computational support
文摘Regional Landslide Susceptibility Zonation(LSZ) is always challenged by the available amount of field data, especially in southwestern China where large mountainous areas and limited field information coincide. Statistical learning algorithms are believed to be superior to traditional statistical algorithms for their data adaptability. The aim of the paper is to evaluate how statistical learning algorithms perform on regional LSZ with limited field data. The focus is on three statistical learning algorithms, Logistic Regression(LR), Artificial Neural Networks(ANN) and Support Vector Machine(SVM). Hanzhong city, a landslide prone area in southwestern China is taken as a study case. Nine environmental factors are selected as inputs. The accuracies of the resulting LSZ maps are evaluated through landslide density analysis(LDA), receiver operating characteristic(ROC) curves and Kappa index statistics. The dependence of the algorithm on the size of field samples is examined by varying the sizes of the training set. The SVM has proven to be the most accurate and the most stable algorithm at small training set sizes and on all known landslide sizes. The accuracy of SVM shows a steadilyincreasing trend and reaches a high level at a small size of the training set, while accuracies of LR and ANN algorithms show distinct fluctuations. The geomorphological interpretations confirm the strength of SVM on all landslide sizes. Our results show that the strengths of SVM in generalization capability and model robustness make it an appropriate and efficient tool for regional LSZ with limited landslide field samples.
基金Project(2012QNZT050)supported by the Special Fund for Basic Scientific Research of Central Colleges,ChinaProjects(51208518,U1361204,51208519,51108464)supported by the National Natural Science Foundation of China+1 种基金Project supported by the Postdoctoral Foundation of Central South University,ChinaProjects(2013RS4030,2012RS4002)sponsored by Hunan Postdoctoral Scientific Program,China
文摘The process and characteristics of loading on high-speed railway bridge pile foundation were firstly obtained by means of field research and analysis,and the corresponding loading function was presented.One-dimensional consolidation equation of elastic multilayered soils was then established with single drainage or double drainages under multilevel loading.Moreover,the formulas for calculating effective stress and settlement were derived from the Laplace numerical inversion transform.The three-dimensional composite analysis method of bridge pile group was improved,where the actual load conditions of pile foundation could be simulated,and the consolidation characteristics of soil layers beneath pile were also taken into account.Eventually,a corresponding program named LTPGS was developed to improve the calculation efficiency.The comparison between long-term settlement obtained from the proposed method and the in-situ measurements of pile foundation was illustrated,and a close agreement is obtained.The error between computed and measured results is less than 1 mm,and it gradually reduces with time.It is shown that the proposed method can effectively simulate the long-term settlement of pile foundation and program LTPGS can provide a reliable estimation.
基金Project(200612) supported by Hunan Province Transportation Department of China
文摘Large-scale field shear tests on ten specimens of the red-sandstone embankment at a highway in Hunan,China,were performed to examine mechanical characteristics and parameters of red-sandstone.The curves of thrust-displacement,failure mode,and shear strength parameters for red-sandstone with different water contents,different compactions,and different grain size distributions were obtained from the tests.A practical procedure of in-situ test for red-sandstone embankment was proposed to normalize the test equipment and test steps.Based on three-dimensional thrust-sliding limit equilibrium method,the formulas for calculating strength parameters of red-sandstone considering three-dimensional sliding surface were inferred.The results show that red-sandstone has typical complete curves of stress-strain,strain softening,which are caused by the special structure of red-sandstone;water content and compaction are important factors for strength and failure mode of red-sandstone;The average value of cohesion and internal friction angle of the specimens calculated by three-dimensional technique are 21.56 kPa and 29.29°,respectively,and those by traditional two-dimensional method are 25.52 kPa and 33.76°,respectively.
基金Project(41202220) supported by the National Natural Science Foundation of ChinaProject(20120022120003) supported by the Research Fund for the Doctoral Program of Higher Education, China+1 种基金Project(2-9-2012-65) supported by the Fundamental Research Funds for the Central Universities, ChinaProject(2013006) supported by the Research Fund for Key Laboratory on Deep GeoDrilling Technology, Ministry of Land and Resources, China
文摘A new type of pit supporting structure, which was tested and verified using the sensor monitoring technology, was presented. The new supporting structure is assembled by prefabricated steel structural units. The adjacent steel structural units are jointed with fasteners, and each steel structural unit has a certain radian and is welded by two steel tubes and one piece of steel disc. In order to test and verify the reliability of the new supporting structure, the field tests are designed. The main monitoring programs include the hoop stress of supporting structure, lateral earth pressure, and soil deformation. The monitoring data of the field tests show that the new supporting structure is convenient, reliable and safe.
基金Supported by the National Natural Science Foundation of China (51176141)the Natural Science Foundation of Tianjin(11JCZDJC22500)
文摘ERT(electrical resistance tomography) is effective method for visualization of multiphase flows,offering some advantages of rapid response and low cost,so as to explore the transient hydrodynamics.Aiming at this target,a fully programmable and reconfigurable FPGA(field programmable gate array)-based Compact PCI(peripheral component interconnect) bus linked sixteen-channel ERT system has been presented.The data acquisition system is carefully designed with function modules of signal generator module;Compact PCI transmission module and data processing module(including data sampling,filtering and demodulating).The processing module incorporates a powerful FPGA with Compact PCI bus for communication,and the measurement process management is conducted in FPGA.Image reconstruction algorithms with different speed and accuracy are also coded for this system.The system has been demonstrated in real time(1400 frames per second for 50 kHz excitation) with signal-noise-ratio above 62 dB and repeatability error below 0.7%.Static experiments have been conducted and the images manifested good resolution relative to the actual object distribution.The parallel ERT system has provided alternative experimental platform for the multiphase flow measurements by the dynamic experiments in terms of concentration and velocity.
文摘It has been 30 years since the family planning policy had been implemented in the last 1970s. Today, the first generation of only child has already reached thirties and their parents have entered into old age so that they may confront such a dilemma situation in which they should not only look after their own child but also take care of their parents. The paper find the different demand of the aging people in different type of family through the site investigation about pension service demand in three different kinds of communities in Cao Hejing. The survey mainly make a statistical analysis in economic situation, life care and emotional solace through the on-site questionnaire and interview, finding the particularity of the only child family, sorting out the best pension service strategy for the one-child family through the analysis research and the reference of international practice.
文摘A survey to identify constraints and design strategies to improve the camel milk and meat value chains was conducted in northern Kenya using Participatory Integrated Community Development (PICD), Focus Group Discussions (FGD), among other methods. In a second step, field testing of an intervention on milk and meat hygiene was carried out at household level. Survey results indicated that about 50% of marketable camel milk was not sold, 30% of marketed camel milk per annum was sold in sour state at US$ 0.13 lower that the price of a litre of fresh milk while processed meat got spoiled along the chain. Annual economic losses associated with milk spoilage were estimated at US$ 961,538.5. Preliminary findings of the field testing indicated that an additional 3 million litres of camel milk was sold in fresh state, giving an annual saving of US$ 384,615.4. Increased profitability of up to 60% compared to 30% before the intervention was reported among nyirinyiri processors. In conclusion, economic potential of the camel could be fully exploited by facilitating adoption of interventions such as hygiene, among others at all levels of the camel milk and meat value chains.
基金supported by the State Key Laboratory of Coal Resources and Sate Mining,China University of Mining and Technology (No.SKLCRSM13X07)the National Natural Science Foundation of China (No.51174195)+1 种基金Chinese National Programs for Fundamental Research and Development (No.2013CB227900)the Fundamental Research Funds for the Central Universities (No.2014XT01)
文摘A reasonable unsupported roof distance(URD) when advancing underground coal mine roadways can contribute greatly to safe and rapid roadway development.A mechanical model of the roof,using the relationship between the roof stress distribution and URD,obtained by the difference method,and roof stability according to the in-situ roof stress and rock mass strength was developed.We subsequently designed a proper range of URD,developed a testing method of URD with the function of mining protection,evaluated roof stability through analyzing the test data and then determined a reasonable URD.Considering the factors of the geological conditions,the immediate roof stability and the efficiency of the labor arrangement system,the URD of the advancing roadway of 9802 working face in Zhangshuanglou coal mine was determined to be 6 m using the proposed method.The results show that,when a 2 m length of roadway was reinforced by temporary support and high pre-stressed bolt support after the roadway advancement of 6 m per cycle,the speed and the security of the roadway development can be achieved and the advance rate can reach more than 400 m per month.
文摘The tourism consumption behavior of the young people has significant effect on the present social tourism consumption behavior. Intensifying the research on tourism consumption behavior of the youth group helps to explore the hot spot of tourism consumption, and designing specific marketing programs and taping into consumption potential is the key to market development. The research takes the university students in the youth group as an example to analyze the features and difference of tourism consumption behavior and observe tourism consumption marketing of the university students, for providing reference for the expansion of tourism market.
文摘The design, manufacture and deployment of embedded systems become increasingly complex and multidisciplinary process. Before the steps of manufacturing and deployment, a simulation and validation phase is necessary. In this paper, a WSN (wireless sensors network) emulator, implemented on a FPGA, is described by: describing some models as examples, how multiple simulations can be done when the device was configured and programmed once, and how results from the behavioral emulator can be extracted. The diversity of applications and the typically scarce node resources set very tight constraints to WSN. It is not possible to fulfill all requirements with a general purpose WSN, for which reason the rapid development of application specific WSNs is preferred. A new emulator for the design, simulation, and evaluation of WSNs, implemented on a very dense FPGA (field programmable gate arrays), is presented, exploring the parallelism and his resources to do a very rapid simulation ofa WSN for long periods, and without overloading memory by the intermediate data.
文摘The paper analyze and design and implement a remote control system based on embedded web server network. A computer network remote control system mainly includes server, client and the control information. Server registration information realize the user command; client provides network hardware, software and other system resources, the system response message and then feedback service instruction. The research results show that, the embedded web server can be assigned to the field device user information through the browser, field device data also can access to the browser through the web server. In order to achieve remote monitoring, control, diagnostics and configuration of the equipment.
文摘This paper examines the impacts of market-oriented electricity reform on macroeconomic variables. It develops an ad hoc econometric model for this purpose, using a panel data of 19 developed countries plus seven Australian States for the period of 1970-2008. Significance of the impacts is firstly tested against three distinct institutional features of electricity reform, namely: (1) organizational restructuring (i.e., functional unbundling of traditionally vertically integrated industry); (2) market restructuring (introduction of mandatory bid-based spot market); and (3) privatization. The extents of the impacts are, then, quantified in terms of relative contribution of such institutional changes to aggregate output growth in short-run, medium-run and long-run. The results reveal that only functional unbundling has made significant contribution to output growth. The results, further, specify that functional unbundling has made, on average, an additional 0.06% and 2.7% contribution to output growth rate in medium-run and long-run respectively.
文摘The paper deals with the comparison of three different digital devices used for the computing of permanent magnet synchronous motor (PMSM) model. Model is used for virtual high frequency injection method (VHFIM) sensorless control, where injection and acting voltages are virtual ones. For computing the whole PMSM model, differential equations are used. The paper is focused on performance analysis of computing speed and accuracy of field-programmable gate array (FPGA) device, digital signal controller and Power PC microcontroller and results are compared.
基金supported by National Research Foundation of Korea (NRF) funded by the Korea government (MEST) (Grant No.2010-0029119)
文摘High-precision(±0.1 ppm) and high-frequency(hourly averaged) in situ measurements of atmospheric carbon dioxide(CO2) were made for the first time from August 2005 to July 2007 at Yanbian,China using a non-dispersive Infrared(NDIR) analyzer with National Oceanic and Atmospheric Administration/Earth System Research Laboratory(NOAA/ESRL) standards.The results of these measurements are presented in this paper and are used to investigate the regional representativeness of regional background data at Yanbian and determine the CO2 emission source regions in Northeast Asia.The phase of the monthly variations at Yanbian reflects the special regional characteristics,which were overall in excellent agreement with other observatories in the middle-to-high latitudes in the Northern Hemisphere.Applying a hybrid receptor model to the regional emission source events in cold period(November-April),we estimated the distribution of the major CO2 emissions in the northeast Asia.The results indicated that the strongest potential emission areas contributing to Yanbian are the Beijing & Tianjin metropolitan areas,southwestern part of Shandong Province including Jinan,and Vladivostok.The results of this study reveal the usefulness of in situ CO2 measurements at Yanbian in establishing the scientific foundation for monitoring the large CO2 emission areas in northern China and Russia.Continued monitoring of CO2 at Yanbian within a regional network should provide significant contributions to both understanding the global/regional carbon cycle and constraining "top-down" emissions in Northeast Asia.