Selection of negative samples significantly influences landslide susceptibility assessment,especially when establishing the relationship between landslides and environmental factors in regions with complex geological ...Selection of negative samples significantly influences landslide susceptibility assessment,especially when establishing the relationship between landslides and environmental factors in regions with complex geological conditions.Traditional sampling strategies commonly used in landslide susceptibility models can lead to a misrepresentation of the distribution of negative samples,causing a deviation from actual geological conditions.This,in turn,negatively affects the discriminative ability and generalization performance of the models.To address this issue,we propose a novel approach for selecting negative samples to enhance the quality of machine learning models.We choose the Liangshan Yi Autonomous Prefecture,located in southwestern Sichuan,China,as the case study.This area,characterized by complex terrain,frequent tectonic activities,and steep slope erosion,experiences recurrent landslides,making it an ideal setting for validating our proposed method.We calculate the contribution values of environmental factors using the relief algorithm to construct the feature space,apply the Target Space Exteriorization Sampling(TSES)method to select negative samples,calculate landslide probability values by Random Forest(RF)modeling,and then create regional landslide susceptibility maps.We evaluate the performance of the RF model optimized by the Environmental Factor Selection-based TSES(EFSTSES)method using standard performance metrics.The results indicated that the model achieved an accuracy(ACC)of 0.962,precision(PRE)of 0.961,and an area under the curve(AUC)of 0.962.These findings demonstrate that the EFSTSES-based model effectively mitigates the negative sample imbalance issue,enhances the differentiation between landslide and non-landslide samples,and reduces misclassification,particularly in geologically complex areas.These improvements offer valuable insights for disaster prevention,land use planning,and risk mitigation strategies.展开更多
The spraying robot for building exterior walls is an innovative technology in the field of modern construction.This paper discusses its design structure,application cases,technical benefits,and industrial impacts.Rese...The spraying robot for building exterior walls is an innovative technology in the field of modern construction.This paper discusses its design structure,application cases,technical benefits,and industrial impacts.Research shows that this type of robot improves the efficiency and quality of exterior wall construction.Its intelligent design enhances operation accuracy and safety,reduces costs and risks,and strengthens application ability in complex environments,showing broad application prospects and symbolizing the development trend of intelligence and automation in the industry.In the future,it is necessary to strengthen its intelligence and adaptive ability further,explore multi-function design,promote automation technology,and ensure construction safety and economic benefits.展开更多
In this paper,we study the weighted higher order semilinear equation in an exterior domain(-△)^(m)u=|x|^(α)g(u)in R^(N)\B_(R_(0)),where N≥1,m≥2 are integers,α>-2m,g is a continuous and nondecreasing function i...In this paper,we study the weighted higher order semilinear equation in an exterior domain(-△)^(m)u=|x|^(α)g(u)in R^(N)\B_(R_(0)),where N≥1,m≥2 are integers,α>-2m,g is a continuous and nondecreasing function in(0,+∞)and positive in(0,+∞),B_(R_(0))is the ball of the radius R0 centered at the origin.We prove that a positive supersolution of the problem which verifies(-△)_(i)u>0 in R^(N)\B_(R_(0))(i=0,…,m-1)exists if and only if N>2m and∫_(0)^(δ)g(t)/t^(2(N-m)+α/N-2m)dt<∞,,for someδ>0.We further obtain some existence and nonexistence results for the positive solution to the Dirichlet problem when g(u)=u^(p)with p>1,by using the Pohozaev identity and an embedding lemma of radial Sobolev spaces.展开更多
In recent years,ozone has become one of the key pollutants affecting the urban air qual-ity.Direct catalytic decomposition of ozone emerges as an effective method for ozone re-moval.Field experimentswere conducted to ...In recent years,ozone has become one of the key pollutants affecting the urban air qual-ity.Direct catalytic decomposition of ozone emerges as an effective method for ozone re-moval.Field experimentswere conducted to evaluate the effectiveness of exteriorwall coat-ings with ozone decomposition catalysts for ozone removal in practical applications.ANSYS 2020R1 software was first used for simulation and analysis of ozone concentration and flow fields to investigate the decomposition boundary of these wall coatings.The results show that the exterior wall coatings with manganese-based catalysts can effectively reduce the ozone concentration near the wall coating.The ozone decomposition efficiency is nega-tively correlated with the distance fromthe coating and the decomposition boundary range is around 18 m.The decomposition boundary will increase with the increase of tempera-ture,and decrease with the increase of the wind speed and the relative humidity.These results underscore the viability of using exterior wall coatings with catalysts for controlling ozone pollution in atmospheric environments.This approach presents a promising avenue for addressing ozone pollution through self-purifying materials on building external wall.展开更多
The design principles for conventional reinforced concrete structures have gradually transitioned to seismic-resistant design since the 1970s.However,until recently,the implementation of strength capacity and ductilit...The design principles for conventional reinforced concrete structures have gradually transitioned to seismic-resistant design since the 1970s.However,until recently,the implementation of strength capacity and ductility design has not been rigorously enforced inmany developing countries that are prone to seismic risks.Numerous studies have evaluated the effectiveness of joint behavior based on both ductile and non-ductile designs under cyclic loading.Previous research has demonstrated that enhancing joint regions with Ultra-High Performance Steel Fiber Reinforced Concrete(UHPSFRC)significantly improves the seismic resistance of structural components.This paper presents a detailed analysis of the considerable improvements in energy dissipation capacity and stiffness degradation observed in both reinforced test samples compared to the control sample.Furthermore,assessing the effective performance of enhanced reinforced concrete joints is a critical parameter for evaluating the feasibility of this approach.The findings highlight the potential for UHPSFRC to enhance the resilience of concrete structures under seismic loads,providing a viable solution to improve the safety and durability of infrastructure in earthquake-prone regions.This study aims to inform future design methodologies and standards in seismic-resistant construction in developing nations,emphasizing the importance of adopting innovative materials to mitigate earthquake risks effectively.展开更多
The estimation of orientation parameters and correction of lens distortion are crucial problems in the field of Unmanned Aerial Vehicles(UAVs)photogrammetry.In recent years,the utilization of UAVs for aerial photogram...The estimation of orientation parameters and correction of lens distortion are crucial problems in the field of Unmanned Aerial Vehicles(UAVs)photogrammetry.In recent years,the utilization of UAVs for aerial photogrammetry has witnessed a surge in popularity.Typically,UAVs are equipped with low-cost non-metric cameras and a Position and Orientation System(POS).Unfortunately,the Interior Orientation Parameters(IOPs)of the non-metric cameras are not fixed.Whether the lens distortions are large or small,they effect the image coordinates accordingly.Additionally,Inertial Measurement Units(IMUs)often have observation errors.To address these challenges and improve parameter estimation for UAVs Light Detection and Ranging(LiDAR)and photogrammetry,this paper analyzes the accuracy of POS observations obtained from Global Navigation Satellite System Real Time Kinematic(GNSS-RTK)and IMU data.A method that incorporates additional known conditions for parameter estimation,a series of algorithms to simultaneously solve for IOPs,Exterior Orientation Parameters(EOPs),and camera lens distortion correction parameters are proposed.Extensive experiments demonstrate that the coordinates measured by GNSS-RTK can be directly used as linear EOPs;however,angular EOP measurements from IMUs exhibit relatively large errors compared to adjustment results and require correction during the adjustment process.The IOPs of non-metric cameras vary slightly between images but need to be treated as unknown parameters in high precision applications.Furthermore,it is found that the Ebner systematic error model is sensitive to the choice of the magnification parameter of the photographic baseline length in images,it should be set as less than or equal to one third of the photographic baseline to ensure stable solutions.展开更多
The sequential dispersing results of aerial cluster bomb are discussed. The ballistic model and the mod- el for impact point distribution of bullets are established. The main factors influencing impact point distribut...The sequential dispersing results of aerial cluster bomb are discussed. The ballistic model and the mod- el for impact point distribution of bullets are established. The main factors influencing impact point distribution are analyzed by numerical simulation. And the feasibility of improving distribution effect through sequential dis- persing is validated. Sequential dispersion and optimized airdrop parameters can help to achieve better battle effec- tiveness.展开更多
To expand scanning area and attack range without changing the inner structure of intelligent warhead, a new arrangement mode of the scanner for intelligent mine is proposed. The required coordinate systems are es...To expand scanning area and attack range without changing the inner structure of intelligent warhead, a new arrangement mode of the scanner for intelligent mine is proposed. The required coordinate systems are established firstly on the basis of advanced dynamics principle. and the exterior ballistics equations are deduced. Then the equations of scanning trails are established by the method of space analytic geometry. To get the scanning trails. the differential equations are transformed into discrete simulation model using the algorithm of fourth order Runge-Kutta and then are simulated using Matlab. Compared with the scanning trails obtained by the traditional layout of scanner, the scanning trails obtained by the proposed layout of scanner has larger horizontal range of scanning circle and bigger trarget acquisition probability. Therefore, the new arrangement mode of the scanner for intelligent mine can increase attack range.展开更多
The components of railway landscape were analyzed,and the railway landscape was classified as railway interior and exterior landscape from the perspective of its characters.After analysis and summarization,the compone...The components of railway landscape were analyzed,and the railway landscape was classified as railway interior and exterior landscape from the perspective of its characters.After analysis and summarization,the components and contents of the railway landscape factors were put forward.展开更多
[Objective] The aim was to analyze the exterior quality and physical prop- erties of Hongda Tobacco in Yunnan Province, thus providing references for planting planning, technology and selection of raw materials. [Meth...[Objective] The aim was to analyze the exterior quality and physical prop- erties of Hongda Tobacco in Yunnan Province, thus providing references for planting planning, technology and selection of raw materials. [Method] Hongda C3F progenies were chosen from 24 villages and towns in Qujing, Kunming, Baoshan and Dali, and the concerning exterior quality and physical properties were analyzed through cluster analysis. [Result] The openness and width of C3F differed significantly among Qujing, Kunming, Baoshan and Dali. The thickness, stem content, equilibrium moisture con- tent extremely differed, and density and filling power varied significantly. Most physi- cal properties, such as equilibrium moisture content and density, of Dali Hongda were quite different from those in Qujing, Kunming and Baoshan, indicating that Dali Hongda enjoys special characteristics in physical properties. In addition, stem content in east, center and west areas of Yunnan Province differed significantly and Hongda in Yunnan could be classified into four species according to physical property. [Conclusion] The research has laid basis for planting planning, technology and raw mate- rials selection of Hongda tobacco.展开更多
Let F be a field and char F = p > 3. In this paper the derivation algebras of Lie superalgebras W and S of Cartan-type over F are determined by the calculating method.
Noise is one of the key issues in the operation of high-speed railways, with sound source localisation and its transfer path as the two major aspects. This study investigates both the exterior and interior sound sourc...Noise is one of the key issues in the operation of high-speed railways, with sound source localisation and its transfer path as the two major aspects. This study investigates both the exterior and interior sound source distribution of a high-speed train and presents a method for performing the contribution analysis of airborne sound with regard to the interior noise. First, both exterior and interior sound source locations of the high-speed train are identified through in-situ measurements. Second, the sound source contribution for di erent regions of the train and the relationships between the exterior and interior noises are analysed. Third, a method for conducting the contribution analysis of airborne sound with regard to the interior noise of the high-speed train is described. Lastly, a case study on the sidewall area is carried out, and the contribution of airborne sound to the interior noise of this area is obtained. The results show that, when the high-speed train runs at 310 km/h, dominant exterior sound sources are located in the bogie and pantograph regions, while main interior sound sources are located at the sidewall and roof. The interior noise, the bogie area noise and the sound source at the middle of the coach exhibit very similar rates of increase with increasing train speed. For the selected sidewall area, structure-borne sound dominates in most of the 1/3 octave bands.展开更多
The Huanghe and Yongding rivers were formed before the early and middle Pliocene epoch. Then they became interior rivers because of the appearance of interior fault lake basins at the end of the Pliocene epoch. The in...The Huanghe and Yongding rivers were formed before the early and middle Pliocene epoch. Then they became interior rivers because of the appearance of interior fault lake basins at the end of the Pliocene epoch. The interior flow period continued until the end of the early Pleistocene or the middle pf the Middle Pleistocene, and then they changed into the exterior rivers again till today.展开更多
Knowledge of impact conditions is critical to evaluating the terminal impact performance of a projectile.For a small caliber bullet,in-flight velocity has been precisely measured for decades using detection screens,bu...Knowledge of impact conditions is critical to evaluating the terminal impact performance of a projectile.For a small caliber bullet,in-flight velocity has been precisely measured for decades using detection screens,but accurately quantifying the orientation of the bullet on a target has been more challenging.This report introduces the Automated Small-Arms Photogrammetry(ASAP)analysis method used to measure,model,and predict the orientation of a small caliber bullet before reaching an impact surface.ASAP uses advanced hardware developed by Sydor Technologies to record a series of infrared digital photographs.Individual images(four orthogonal pairs)are processed using computer vision algorithms to quantify the orientation of the projectile and re-project its precise position and orientation into a three-dimensional muzzle-fixed coordinate system.An epicyclic motion model is fit to the measured data,and the epicyclic motion is extrapolated to the target location.Analysis results are fairly immediate and may be reviewed during testing.Prove-out demonstrations have shown that the impact-angle prediction capability is less than six hundredths of a degree for the 5.56 mm ball round tested.Keywords:Yaw,Terminal ballistics,Exterior ballistics,Test&evaluation,Computer vision,Image processing,Angle of展开更多
Landscape design for a green community should be favorable for the ambient ecological environment and for enhancement of both the local climate of a residential area and the environmental quality of life. This paper p...Landscape design for a green community should be favorable for the ambient ecological environment and for enhancement of both the local climate of a residential area and the environmental quality of life. This paper presents optimization methods for plant landscape design that take account of results of comparisons of noise reduction effects, heat island temperature decreases and effects on ventilation. These methods are based on different plant configurations and various luminous environments, such as exterior sunshine and shaded areas after the simulation of exterior luminous, acoustic and thermal environments of a residential area using the analytic software ECOTECT, CADNA/A, and PHEONICS. Three different types of residential buildings are simulated including a faculty apartment in the Xixi Campus of Zhejiang University, the Huaqing Villa and the Gangwan Jiayuan faculty apartment of Zhejiang University, China, based on green building design theory. In addition, the methods and process flow of landscape design of green residential areas are also described for the improvement of the exterior physical living environment.展开更多
This paper introduces a novel approach for controlling the exterior ballistic properties of spin-stabilized bullets by optimizing their internal mass distributions. Specifically, the properties of interest are the bul...This paper introduces a novel approach for controlling the exterior ballistic properties of spin-stabilized bullets by optimizing their internal mass distributions. Specifically, the properties of interest are the bullets’ stability characteristics that are examined through dynamic and gyroscopic stability parameters.New analytical expressions for aerodynamic quantities are also derived to address the compressibility of air. These expressions are utilized in a bullet model that enables efficient computation of the stability parameters for a given mass distribution. The bullet model is used in the formulation of nonlinear optimization problems that provide optimal mass distributions with respect to given goals, i.e., desired stability characteristics. The bullet types investigated in this paper are a long range bullet and a limited range training bullet. In the optimization of the mass distribution of the long range bullet, the goal is that the bullet stays stable for as long as possible. The mass distribution of the training bullet is optimized such that the bullet is stable at launch but becomes unstable shortly afterwards. The global optimal solutions obtained with the new approach fulfill the desired stability characteristics better than currently used uniformly filled bullets. Overall, the optimization approach reveals a new goal focused philosophy for bullet design compared to current trial and error design practices.展开更多
OBJECTIVE: To assess the efficacy and safety in 105 patients with seasonal Influenza in Beijing, the mixture prepared with Chinese medicines follows the treatment regimen of releasing exterior cold andclearing interio...OBJECTIVE: To assess the efficacy and safety in 105 patients with seasonal Influenza in Beijing, the mixture prepared with Chinese medicines follows the treatment regimen of releasing exterior cold andclearing interior heat.METHODS: Total 330 patients with seasonal influenza were enrolled and randomly and averagely divided into the Chinese herbal medicine, the western medicine and the Chinese patent medicine group. They were treated with Chinese medicine Oseltamivir Phosphate Capsules and the Scattering Wind and Resolving Toxins Capsules. The main efficacy indicators were the antifebrile onset time and recovery time of body temperature. The efficacy and safety of the mixture was scientifically evaluated. Comparisons of several variables were analyzed.RESULTS: Median antifebrile onset time of the Chinese herbal medicine group was significantly shorter than the western medicine group(P < 0.05) and the Chinese patent medicine group(P < 0.05). The median antifebrile recovery time of the Chinese herbal medicine group was significantly shorter than the Chinese patent medicine group(P <0.05). The groups evaluated by TCM symptom pattern effect, both the Chinese herbal medicine group and Western Medicine group were better than the Chinese patent medicine group(P <0.05). The disappearance rate of main symptoms and some minor symptom patterns of the Chinese herbal medicine group were higher than the other 2 groups.CONCLUSION: The mixture of releasing exterior cold and clearing interior heat could significantly shorten the fever time with safety.展开更多
The present paper proposes a detection method for building exterior wall cracks since manual detection methods have high risk and low efficiency.The proposed method is based on Unmanned Aerial Vehicle(UAV)and computer...The present paper proposes a detection method for building exterior wall cracks since manual detection methods have high risk and low efficiency.The proposed method is based on Unmanned Aerial Vehicle(UAV)and computer vision technology.First,a crack dataset of 1920 images was established using UAV to collect the images of a residential building exterior wall under different lighting conditions.Second,the average crack detection precisions of different methods including the Single Shot MultiBox Detector,You Only Look Once v3,You Only Look Once v4,Faster Regional Convolutional Neural Network(R-CNN)and Mask R-CNN methods were compared.Then,the Mask R-CNN method with the best performance and average precision of 0.34 was selected.Finally,based on the characteristics of cracks,the utilization ratio of Mask R-CNN to the underlying features was improved so that the average precision of 0.9 was achieved.It was found that the positioning accuracy and mask coverage rate of the proposed Mask R-CNN method are greatly improved.Also,it will be shown that using UAV is safer than manual detection because manual parameter setting is not required.In addition,the proposed detection method is expected to greatly reduce the cost and risk of manual detection of building exterior wall cracks and realize the efficient identification and accurate labeling of building exterior wall cracks.展开更多
Geologic surface approximation is profoundly affected by the presence, density and location of scattered geologic input data. Many studies have recognized the importance of utilizing varied sources of information when...Geologic surface approximation is profoundly affected by the presence, density and location of scattered geologic input data. Many studies have recognized the importance of utilizing varied sources of information when reconstructing a surface. This paper presents an improved geologic surface approximation method using a multiquadric function and borehole data. Additional information, i.e., inequality elevation and dip-strikes data extracted from outcrops or mining faces, is introduced in the form of physical constraints that control local changes in the estimated surface. Commonly accepted hypothesis states that geologic surfaces can be approximated to any desired degree of exactness by the summation of regular, mathematically defined, surfaces: in particular displaced quadric forms. The coefficients of the multiquadric functions are traditionally found by a least squares method. The addition of physical constraints in this work makes such an approach into a non-deterministic polynomial time problem. Hence we propose an objective function that represents the quality of the estimated surface and that includes the additional constraints by incorporation of a penalty function. Maximizing the smoothness of the estimated surface and its fitness to the additional constraints then allows the coefficients of the multiquadric function to be obtained by iterative methods. This method was implemented and demonstrated using data collected from the 81'st coal mining area of the Huaibei Coal Group.展开更多
The authors first give the definition of degenerate weakly （K1,K2）-quasiregular mappings using the technique of exterior power and exterior differential forms, and then, using the method of McShane extension, a usef...The authors first give the definition of degenerate weakly （K1,K2）-quasiregular mappings using the technique of exterior power and exterior differential forms, and then, using the method of McShane extension, a useful inequality is obtained, which can be used to derive the self-improving regularity.展开更多
基金supported by Natural Science Research Project of Anhui Educational Committee(2023AH030041)National Natural Science Foundation of China(42277136)Anhui Province Young and Middle-aged Teacher Training Action Project(DTR2023018).
文摘Selection of negative samples significantly influences landslide susceptibility assessment,especially when establishing the relationship between landslides and environmental factors in regions with complex geological conditions.Traditional sampling strategies commonly used in landslide susceptibility models can lead to a misrepresentation of the distribution of negative samples,causing a deviation from actual geological conditions.This,in turn,negatively affects the discriminative ability and generalization performance of the models.To address this issue,we propose a novel approach for selecting negative samples to enhance the quality of machine learning models.We choose the Liangshan Yi Autonomous Prefecture,located in southwestern Sichuan,China,as the case study.This area,characterized by complex terrain,frequent tectonic activities,and steep slope erosion,experiences recurrent landslides,making it an ideal setting for validating our proposed method.We calculate the contribution values of environmental factors using the relief algorithm to construct the feature space,apply the Target Space Exteriorization Sampling(TSES)method to select negative samples,calculate landslide probability values by Random Forest(RF)modeling,and then create regional landslide susceptibility maps.We evaluate the performance of the RF model optimized by the Environmental Factor Selection-based TSES(EFSTSES)method using standard performance metrics.The results indicated that the model achieved an accuracy(ACC)of 0.962,precision(PRE)of 0.961,and an area under the curve(AUC)of 0.962.These findings demonstrate that the EFSTSES-based model effectively mitigates the negative sample imbalance issue,enhances the differentiation between landslide and non-landslide samples,and reduces misclassification,particularly in geologically complex areas.These improvements offer valuable insights for disaster prevention,land use planning,and risk mitigation strategies.
基金Design and Research of Intelligent Construction Device for the“Water-in-Sand”Process of High-Rise Building Exterior Wall(Project No.2022KQNCX189)。
文摘The spraying robot for building exterior walls is an innovative technology in the field of modern construction.This paper discusses its design structure,application cases,technical benefits,and industrial impacts.Research shows that this type of robot improves the efficiency and quality of exterior wall construction.Its intelligent design enhances operation accuracy and safety,reduces costs and risks,and strengthens application ability in complex environments,showing broad application prospects and symbolizing the development trend of intelligence and automation in the industry.In the future,it is necessary to strengthen its intelligence and adaptive ability further,explore multi-function design,promote automation technology,and ensure construction safety and economic benefits.
文摘In this paper,we study the weighted higher order semilinear equation in an exterior domain(-△)^(m)u=|x|^(α)g(u)in R^(N)\B_(R_(0)),where N≥1,m≥2 are integers,α>-2m,g is a continuous and nondecreasing function in(0,+∞)and positive in(0,+∞),B_(R_(0))is the ball of the radius R0 centered at the origin.We prove that a positive supersolution of the problem which verifies(-△)_(i)u>0 in R^(N)\B_(R_(0))(i=0,…,m-1)exists if and only if N>2m and∫_(0)^(δ)g(t)/t^(2(N-m)+α/N-2m)dt<∞,,for someδ>0.We further obtain some existence and nonexistence results for the positive solution to the Dirichlet problem when g(u)=u^(p)with p>1,by using the Pohozaev identity and an embedding lemma of radial Sobolev spaces.
基金supported by the National Natural Science Foundation of China(Nos.52470114 and 52022104)the National Key R&D Program of China(No.2022YFC3702802)the Youth Innovation Promotion Association,CAS(No.Y2021020).
文摘In recent years,ozone has become one of the key pollutants affecting the urban air qual-ity.Direct catalytic decomposition of ozone emerges as an effective method for ozone re-moval.Field experimentswere conducted to evaluate the effectiveness of exteriorwall coat-ings with ozone decomposition catalysts for ozone removal in practical applications.ANSYS 2020R1 software was first used for simulation and analysis of ozone concentration and flow fields to investigate the decomposition boundary of these wall coatings.The results show that the exterior wall coatings with manganese-based catalysts can effectively reduce the ozone concentration near the wall coating.The ozone decomposition efficiency is nega-tively correlated with the distance fromthe coating and the decomposition boundary range is around 18 m.The decomposition boundary will increase with the increase of tempera-ture,and decrease with the increase of the wind speed and the relative humidity.These results underscore the viability of using exterior wall coatings with catalysts for controlling ozone pollution in atmospheric environments.This approach presents a promising avenue for addressing ozone pollution through self-purifying materials on building external wall.
文摘The design principles for conventional reinforced concrete structures have gradually transitioned to seismic-resistant design since the 1970s.However,until recently,the implementation of strength capacity and ductility design has not been rigorously enforced inmany developing countries that are prone to seismic risks.Numerous studies have evaluated the effectiveness of joint behavior based on both ductile and non-ductile designs under cyclic loading.Previous research has demonstrated that enhancing joint regions with Ultra-High Performance Steel Fiber Reinforced Concrete(UHPSFRC)significantly improves the seismic resistance of structural components.This paper presents a detailed analysis of the considerable improvements in energy dissipation capacity and stiffness degradation observed in both reinforced test samples compared to the control sample.Furthermore,assessing the effective performance of enhanced reinforced concrete joints is a critical parameter for evaluating the feasibility of this approach.The findings highlight the potential for UHPSFRC to enhance the resilience of concrete structures under seismic loads,providing a viable solution to improve the safety and durability of infrastructure in earthquake-prone regions.This study aims to inform future design methodologies and standards in seismic-resistant construction in developing nations,emphasizing the importance of adopting innovative materials to mitigate earthquake risks effectively.
基金Natural Science Foundation of Hunan Province,China(No.2024JJ8335)Open Topic of Hunan Geospatial Information Engineering and Technology Research Center,China(No.HNGIET2023004).
文摘The estimation of orientation parameters and correction of lens distortion are crucial problems in the field of Unmanned Aerial Vehicles(UAVs)photogrammetry.In recent years,the utilization of UAVs for aerial photogrammetry has witnessed a surge in popularity.Typically,UAVs are equipped with low-cost non-metric cameras and a Position and Orientation System(POS).Unfortunately,the Interior Orientation Parameters(IOPs)of the non-metric cameras are not fixed.Whether the lens distortions are large or small,they effect the image coordinates accordingly.Additionally,Inertial Measurement Units(IMUs)often have observation errors.To address these challenges and improve parameter estimation for UAVs Light Detection and Ranging(LiDAR)and photogrammetry,this paper analyzes the accuracy of POS observations obtained from Global Navigation Satellite System Real Time Kinematic(GNSS-RTK)and IMU data.A method that incorporates additional known conditions for parameter estimation,a series of algorithms to simultaneously solve for IOPs,Exterior Orientation Parameters(EOPs),and camera lens distortion correction parameters are proposed.Extensive experiments demonstrate that the coordinates measured by GNSS-RTK can be directly used as linear EOPs;however,angular EOP measurements from IMUs exhibit relatively large errors compared to adjustment results and require correction during the adjustment process.The IOPs of non-metric cameras vary slightly between images but need to be treated as unknown parameters in high precision applications.Furthermore,it is found that the Ebner systematic error model is sensitive to the choice of the magnification parameter of the photographic baseline length in images,it should be set as less than or equal to one third of the photographic baseline to ensure stable solutions.
基金Supported by the Independent Scientific Research of Nanjing University of Science and Technology(2011YBXM110)~~
文摘The sequential dispersing results of aerial cluster bomb are discussed. The ballistic model and the mod- el for impact point distribution of bullets are established. The main factors influencing impact point distribution are analyzed by numerical simulation. And the feasibility of improving distribution effect through sequential dis- persing is validated. Sequential dispersion and optimized airdrop parameters can help to achieve better battle effec- tiveness.
文摘To expand scanning area and attack range without changing the inner structure of intelligent warhead, a new arrangement mode of the scanner for intelligent mine is proposed. The required coordinate systems are established firstly on the basis of advanced dynamics principle. and the exterior ballistics equations are deduced. Then the equations of scanning trails are established by the method of space analytic geometry. To get the scanning trails. the differential equations are transformed into discrete simulation model using the algorithm of fourth order Runge-Kutta and then are simulated using Matlab. Compared with the scanning trails obtained by the traditional layout of scanner, the scanning trails obtained by the proposed layout of scanner has larger horizontal range of scanning circle and bigger trarget acquisition probability. Therefore, the new arrangement mode of the scanner for intelligent mine can increase attack range.
文摘The components of railway landscape were analyzed,and the railway landscape was classified as railway interior and exterior landscape from the perspective of its characters.After analysis and summarization,the components and contents of the railway landscape factors were put forward.
基金Supported by Project of China Tobacco Yunnan Industrial Co.,Ltd.(2008YL07)Project of Hongyun Honghe Group(HYHH2010YL02)~~
文摘[Objective] The aim was to analyze the exterior quality and physical prop- erties of Hongda Tobacco in Yunnan Province, thus providing references for planting planning, technology and selection of raw materials. [Method] Hongda C3F progenies were chosen from 24 villages and towns in Qujing, Kunming, Baoshan and Dali, and the concerning exterior quality and physical properties were analyzed through cluster analysis. [Result] The openness and width of C3F differed significantly among Qujing, Kunming, Baoshan and Dali. The thickness, stem content, equilibrium moisture con- tent extremely differed, and density and filling power varied significantly. Most physi- cal properties, such as equilibrium moisture content and density, of Dali Hongda were quite different from those in Qujing, Kunming and Baoshan, indicating that Dali Hongda enjoys special characteristics in physical properties. In addition, stem content in east, center and west areas of Yunnan Province differed significantly and Hongda in Yunnan could be classified into four species according to physical property. [Conclusion] The research has laid basis for planting planning, technology and raw mate- rials selection of Hongda tobacco.
文摘Let F be a field and char F = p > 3. In this paper the derivation algebras of Lie superalgebras W and S of Cartan-type over F are determined by the calculating method.
基金Supported by National Key R&D Program of China(Grant No.2016YFE0205200)National Natural Science Foundation of China(Grant No.U1834201)
文摘Noise is one of the key issues in the operation of high-speed railways, with sound source localisation and its transfer path as the two major aspects. This study investigates both the exterior and interior sound source distribution of a high-speed train and presents a method for performing the contribution analysis of airborne sound with regard to the interior noise. First, both exterior and interior sound source locations of the high-speed train are identified through in-situ measurements. Second, the sound source contribution for di erent regions of the train and the relationships between the exterior and interior noises are analysed. Third, a method for conducting the contribution analysis of airborne sound with regard to the interior noise of the high-speed train is described. Lastly, a case study on the sidewall area is carried out, and the contribution of airborne sound to the interior noise of this area is obtained. The results show that, when the high-speed train runs at 310 km/h, dominant exterior sound sources are located in the bogie and pantograph regions, while main interior sound sources are located at the sidewall and roof. The interior noise, the bogie area noise and the sound source at the middle of the coach exhibit very similar rates of increase with increasing train speed. For the selected sidewall area, structure-borne sound dominates in most of the 1/3 octave bands.
文摘The Huanghe and Yongding rivers were formed before the early and middle Pliocene epoch. Then they became interior rivers because of the appearance of interior fault lake basins at the end of the Pliocene epoch. The interior flow period continued until the end of the early Pleistocene or the middle pf the Middle Pleistocene, and then they changed into the exterior rivers again till today.
文摘Knowledge of impact conditions is critical to evaluating the terminal impact performance of a projectile.For a small caliber bullet,in-flight velocity has been precisely measured for decades using detection screens,but accurately quantifying the orientation of the bullet on a target has been more challenging.This report introduces the Automated Small-Arms Photogrammetry(ASAP)analysis method used to measure,model,and predict the orientation of a small caliber bullet before reaching an impact surface.ASAP uses advanced hardware developed by Sydor Technologies to record a series of infrared digital photographs.Individual images(four orthogonal pairs)are processed using computer vision algorithms to quantify the orientation of the projectile and re-project its precise position and orientation into a three-dimensional muzzle-fixed coordinate system.An epicyclic motion model is fit to the measured data,and the epicyclic motion is extrapolated to the target location.Analysis results are fairly immediate and may be reviewed during testing.Prove-out demonstrations have shown that the impact-angle prediction capability is less than six hundredths of a degree for the 5.56 mm ball round tested.Keywords:Yaw,Terminal ballistics,Exterior ballistics,Test&evaluation,Computer vision,Image processing,Angle of
基金Project (No. R1080363) supported by the Zhejiang Provincial Natural Science Foundation of China
文摘Landscape design for a green community should be favorable for the ambient ecological environment and for enhancement of both the local climate of a residential area and the environmental quality of life. This paper presents optimization methods for plant landscape design that take account of results of comparisons of noise reduction effects, heat island temperature decreases and effects on ventilation. These methods are based on different plant configurations and various luminous environments, such as exterior sunshine and shaded areas after the simulation of exterior luminous, acoustic and thermal environments of a residential area using the analytic software ECOTECT, CADNA/A, and PHEONICS. Three different types of residential buildings are simulated including a faculty apartment in the Xixi Campus of Zhejiang University, the Huaqing Villa and the Gangwan Jiayuan faculty apartment of Zhejiang University, China, based on green building design theory. In addition, the methods and process flow of landscape design of green residential areas are also described for the improvement of the exterior physical living environment.
文摘This paper introduces a novel approach for controlling the exterior ballistic properties of spin-stabilized bullets by optimizing their internal mass distributions. Specifically, the properties of interest are the bullets’ stability characteristics that are examined through dynamic and gyroscopic stability parameters.New analytical expressions for aerodynamic quantities are also derived to address the compressibility of air. These expressions are utilized in a bullet model that enables efficient computation of the stability parameters for a given mass distribution. The bullet model is used in the formulation of nonlinear optimization problems that provide optimal mass distributions with respect to given goals, i.e., desired stability characteristics. The bullet types investigated in this paper are a long range bullet and a limited range training bullet. In the optimization of the mass distribution of the long range bullet, the goal is that the bullet stays stable for as long as possible. The mass distribution of the training bullet is optimized such that the bullet is stable at launch but becomes unstable shortly afterwards. The global optimal solutions obtained with the new approach fulfill the desired stability characteristics better than currently used uniformly filled bullets. Overall, the optimization approach reveals a new goal focused philosophy for bullet design compared to current trial and error design practices.
基金Supported by National Science and Technology Support Program:Research on unique treatment and principle of inheritance famous old traditional Chinese doctors(No.2013BAI13B021)The Beijing municipal administration of traditional Chinese medicine inheriting program:workstation of famous doctor Zhou Ping-an construction projectThe Innovative Team Project of Beijing University of Chinese Medicine(No.2011-CXTD-08)
文摘OBJECTIVE: To assess the efficacy and safety in 105 patients with seasonal Influenza in Beijing, the mixture prepared with Chinese medicines follows the treatment regimen of releasing exterior cold andclearing interior heat.METHODS: Total 330 patients with seasonal influenza were enrolled and randomly and averagely divided into the Chinese herbal medicine, the western medicine and the Chinese patent medicine group. They were treated with Chinese medicine Oseltamivir Phosphate Capsules and the Scattering Wind and Resolving Toxins Capsules. The main efficacy indicators were the antifebrile onset time and recovery time of body temperature. The efficacy and safety of the mixture was scientifically evaluated. Comparisons of several variables were analyzed.RESULTS: Median antifebrile onset time of the Chinese herbal medicine group was significantly shorter than the western medicine group(P < 0.05) and the Chinese patent medicine group(P < 0.05). The median antifebrile recovery time of the Chinese herbal medicine group was significantly shorter than the Chinese patent medicine group(P <0.05). The groups evaluated by TCM symptom pattern effect, both the Chinese herbal medicine group and Western Medicine group were better than the Chinese patent medicine group(P <0.05). The disappearance rate of main symptoms and some minor symptom patterns of the Chinese herbal medicine group were higher than the other 2 groups.CONCLUSION: The mixture of releasing exterior cold and clearing interior heat could significantly shorten the fever time with safety.
基金This work was supported in part by the National Natural Science Foundation of China under Grant 51408063,author W.C,http://www.nsfc.gov.cn/in part by the Outstanding Youth Scholars of the Department of Hunan Provincial under Grant 20B031,author W.C,http://kxjsc.gov.hnedu.cn/.
文摘The present paper proposes a detection method for building exterior wall cracks since manual detection methods have high risk and low efficiency.The proposed method is based on Unmanned Aerial Vehicle(UAV)and computer vision technology.First,a crack dataset of 1920 images was established using UAV to collect the images of a residential building exterior wall under different lighting conditions.Second,the average crack detection precisions of different methods including the Single Shot MultiBox Detector,You Only Look Once v3,You Only Look Once v4,Faster Regional Convolutional Neural Network(R-CNN)and Mask R-CNN methods were compared.Then,the Mask R-CNN method with the best performance and average precision of 0.34 was selected.Finally,based on the characteristics of cracks,the utilization ratio of Mask R-CNN to the underlying features was improved so that the average precision of 0.9 was achieved.It was found that the positioning accuracy and mask coverage rate of the proposed Mask R-CNN method are greatly improved.Also,it will be shown that using UAV is safer than manual detection because manual parameter setting is not required.In addition,the proposed detection method is expected to greatly reduce the cost and risk of manual detection of building exterior wall cracks and realize the efficient identification and accurate labeling of building exterior wall cracks.
基金provided by the National Science and Technology Major Project of China (Nos.2009ZX05039-004 and 2009ZX 05039-002)the National Natural Science Foundation of China (Nos.40771167 and 70621001)
文摘Geologic surface approximation is profoundly affected by the presence, density and location of scattered geologic input data. Many studies have recognized the importance of utilizing varied sources of information when reconstructing a surface. This paper presents an improved geologic surface approximation method using a multiquadric function and borehole data. Additional information, i.e., inequality elevation and dip-strikes data extracted from outcrops or mining faces, is introduced in the form of physical constraints that control local changes in the estimated surface. Commonly accepted hypothesis states that geologic surfaces can be approximated to any desired degree of exactness by the summation of regular, mathematically defined, surfaces: in particular displaced quadric forms. The coefficients of the multiquadric functions are traditionally found by a least squares method. The addition of physical constraints in this work makes such an approach into a non-deterministic polynomial time problem. Hence we propose an objective function that represents the quality of the estimated surface and that includes the additional constraints by incorporation of a penalty function. Maximizing the smoothness of the estimated surface and its fitness to the additional constraints then allows the coefficients of the multiquadric function to be obtained by iterative methods. This method was implemented and demonstrated using data collected from the 81'st coal mining area of the Huaibei Coal Group.
基金Research supported by NSFC (10471149)Special Fund of Mathematics Research of Natural Science Foundation of Hebei Province (07M003)Doctoral Foundation of Hebei Province Ministry of Education (B2004103).
文摘The authors first give the definition of degenerate weakly （K1,K2）-quasiregular mappings using the technique of exterior power and exterior differential forms, and then, using the method of McShane extension, a useful inequality is obtained, which can be used to derive the self-improving regularity.
