To transmit customer power data collected by smart meters(SMs)to utility companies,data must first be transmitted to the corresponding data aggregation point(DAP)of the SM.The number of DAPs installed and the installa...To transmit customer power data collected by smart meters(SMs)to utility companies,data must first be transmitted to the corresponding data aggregation point(DAP)of the SM.The number of DAPs installed and the installation location greatly impact the whole network.For the traditional DAP placement algorithm,the number of DAPs must be set in advance,but determining the best number of DAPs is difficult,which undoubtedly reduces the overall performance of the network.Moreover,the excessive gap between the loads of different DAPs is also an important factor affecting the quality of the network.To address the above problems,this paper proposes a DAP placement algorithm,APSSA,based on the improved affinity propagation(AP)algorithm and sparrow search(SSA)algorithm,which can select the appropriate number of DAPs to be installed and the corresponding installation locations according to the number of SMs and their distribution locations in different environments.The algorithm adds an allocation mechanism to optimize the subnetwork in the SSA.APSSA is evaluated under three different areas and compared with other DAP placement algorithms.The experimental results validated that the method in this paper can reduce the network cost,shorten the average transmission distance,and reduce the load gap.展开更多
Designers search for N-nodes peer-to-peer networks that can have O （1） out-degree with O （log2 N） average distance. Peer-to-peer schemes based on de Bruijn graphs are found to meet this requirement. By defining av...Designers search for N-nodes peer-to-peer networks that can have O （1） out-degree with O （log2 N） average distance. Peer-to-peer schemes based on de Bruijn graphs are found to meet this requirement. By defining average load to evaluate the traffic load in a network, we show that in order to decrease the average load, the average distance of a network should decrease while the out-degree should increase. Especially, given out-degree k and N nodes, peer-to-peer schemes based on de Bruijn graphs have lower average load than other existing systems. The out-degree k of de Bruijn graphs should not be O（1） but should satisfy a lower bound described by an inequality κ^κ≥N^2, to ensure that the average load in peer-to-peer schemes based on de Bruijn graphs will not exceed that in Chord system.展开更多
In this paper, we deduce Wiener number of some connected subgraphs in tilings (4, 4, 4, 4) and (4, 6, 12), which are in Archimedean tilings. And compute their average distance.
This paper proposes a new methodology to optimize trajectory of the path for multi-robots using improved gravitational search algorithm(IGSA) in clutter environment. Classical GSA has been improved in this paper based...This paper proposes a new methodology to optimize trajectory of the path for multi-robots using improved gravitational search algorithm(IGSA) in clutter environment. Classical GSA has been improved in this paper based on the communication and memory characteristics of particle swarm optimization(PSO). IGSA technique is incorporated into the multi-robot system in a dynamic framework, which will provide robust performance, self-deterministic cooperation, and coping with an inhospitable environment. The robots in the team make independent decisions, coordinate, and cooperate with each other to accomplish a common goal using the developed IGSA. A path planning scheme has been developed using IGSA to optimally obtain the succeeding positions of the robots from the existing position in the proposed environment. Finally, the analytical and experimental results of the multi-robot path planning were compared with those obtained by IGSA, GSA and differential evolution(DE) in a similar environment. The simulation and the Khepera environment result show outperforms of IGSA as compared to GSA and DE with respect to the average total trajectory path deviation, average uncovered trajectory target distance and energy optimization in terms of rotation.展开更多
In this paper, we analytically discuss the scaling properties of the average square end-to-end distance < R-2 > for anisotropic random walk in D-dimensional space (D >= 2), and the returning probability P-n(r...In this paper, we analytically discuss the scaling properties of the average square end-to-end distance < R-2 > for anisotropic random walk in D-dimensional space (D >= 2), and the returning probability P-n(r(0)) for the walker into a certain neighborhood of the origin. We will not only give the calculating formula for < R-2 > and P-n(r(0)), but also point out that if there is a symmetric axis for the distribution of the probability density of a single step displacement, we always obtain < R-perpendicular to n(2) > similar to n, where perpendicular to refers to the projections of the displacement perpendicular to each symmetric axes of the walk; in D-dimensional space with D symmetric axes perpendicular to each other, we always have < R-n(2)> similar to n and the random walk will be like a purely random motion; if the number of inter-perpendicular symmetric axis is smaller than < R-n(2)> similar to n(2) the dimensions of the space, we must have n for very large n and the walk will be like a ballistic motion. It is worth while to point out that unlike the isotropic random walk in one and two dimensions, which is certain to return into the neighborhood of the origin, generally there is only a nonzero probability for the anisotropic random walker in two dimensions to return to the neighborhood.展开更多
Recognition of the boundaries of farmland plow areas has an important guiding role in the operation of intelligent agricultural equipment.To precisely recognize these boundaries,a detection method for unmanned tractor...Recognition of the boundaries of farmland plow areas has an important guiding role in the operation of intelligent agricultural equipment.To precisely recognize these boundaries,a detection method for unmanned tractor plow areas based on RGB-Depth(RGB-D)cameras was proposed,and the feasibility of the detection method was analyzed.This method applied advanced computer vision technology to the field of agricultural automation.Adopting and improving the YOLOv5-seg object segmentation algorithm,first,the Convolutional Block Attention Module(CBAM)was integrated into Concentrated-Comprehensive Convolution Block(C3)to form C3CBAM,thereby enhancing the ability of the network to extract features from plow areas.The GhostConv module was also utilized to reduce parameter and computational complexity.Second,using the depth image information provided by the RGB-D camera combined with the results recognized by the YOLOv5-seg model,the mask image was processed to extract contour boundaries,align the contours with the depth map,and obtain the boundary distance information of the plowed area.Last,based on farmland information,the calculated average boundary distance was corrected,further improving the accuracy of the distance measurements.The experiment results showed that the YOLOv5-seg object segmentation algorithm achieved a recognition accuracy of 99%for plowed areas and that the ranging accuracy improved with decreasing detection distance.The ranging error at 5.5 m was approximately 0.056 m,and the average detection time per frame is 29 ms,which can meet the real-time operational requirements.The results of this study can provide precise guarantees for the autonomous operation of unmanned plowing units.展开更多
Purpose:The aim of this study is to evaluate the application value of virtual surgical planning in the management of mandibular condylar fractures and to provide a reliable reference.Methods:This was a prospective ran...Purpose:The aim of this study is to evaluate the application value of virtual surgical planning in the management of mandibular condylar fractures and to provide a reliable reference.Methods:This was a prospective randomized controlled study and recruited 50 patients requiring surgical treatment for their mandibular condylar fractures.The inclusion criteria were patients(1)diagnosed with a condylar fracture by two clinically experienced doctors and required surgical treatment;(2)have given consent for the surgical treatment;and(3)had no contraindications to the surgery.Patients were excluded from this study if:(1)they were diagnosed with a non-dislocated or only slightly dislocated condylar fracture;(2)the comminuted condylar fracture was too severe to be treated with internal reduction and fixation;or(3)patients could not complete follow-up for 3 months.There were 33 male and 17 female patients with 33 unilateral condylar fractures and 17 bilateral condylar fractures included.The 50 patients were randomly(random number)divided into control group(25 patients with 35 sides of condylar fractures)and experimental group(25 patients with 32 sides of condylar fractures).Virtual surgical planning was used in the experimental group,but only clinical experience was used in the control group.The patients were followed up for 1,3,6 and 12 months after operation.Variables including the rate of perfect reduction by radiological analysis,the average distance of deviation between preoperative and postoperative CT measurements using Geomagic software and postoperative clinical examinations(e.g.,mouth opening,occlusion)were investigated for outcome measurement.SPSS 19 was adopted for data analysis.Results:The average operation time was 180.60 min in the experimental group and 223.2 min in the control group.One week postoperatively,CT images showed that the anatomic reduction rate was 90.63%(29/32)in the experimental group and 68.57%(24/35)in the control group,revealing significant difference(X^(2)=4.919,p=0.027).Geomagic comparative analysis revealed that the average distance of deviation was also much smaller in the experimental group than that in the control group(0.639 mm vs.0.995 mm;t=3.824,p<0.001).Conclusion:These findings suggest that virtual surgical planning can assist surgeons in surgical procedures,reduce operative time,and improve the anatomic reduction rate&accuracy,and thus of value in the diagnosis and treatment of condylar fractures.展开更多
Some physicists depicted the molecular structure SnCl_2 · 2（H_2O） by a piece of an Archimedean tiling（4.8.8） that is a partial cube. Inspired by this fact, we determine Archimedean tilings whose connected sub...Some physicists depicted the molecular structure SnCl_2 · 2（H_2O） by a piece of an Archimedean tiling（4.8.8） that is a partial cube. Inspired by this fact, we determine Archimedean tilings whose connected subgraphs are all partial cubes. Actually there are only four Archimedean tilings,（4.4.4.4）,（6.6.6）,（4.8.8） and（4.6.12）, which have this property. Furthermore, we obtain analytical expressions for Wiener numbers of some connected subgraphs of（4.8.8） and（4.6.12） tilings. In addition, we also discuss their asymptotic behaviors.展开更多
Under a relatively realistic model, this paper theoretically analyzes the road traffic status inside an urban working field, including its radial roads and circular ones. Concretely, the radial and the circular averag...Under a relatively realistic model, this paper theoretically analyzes the road traffic status inside an urban working field, including its radial roads and circular ones. Concretely, the radial and the circular average traveling distances of a car commuter in a tiny ring with wide dx are first derived, and then the necessary road area, road area rate distributions, the proportion between the radial and the circular roads to be needed are also calculated. The results presented here and the properties shown through the numerical analysis are considered to be significant at the very beginning stage of designing an urban city.展开更多
基金supported by the Fujian University of Technology under Grant GYZ20016,GY-Z18183,and GY-Z19005partially supported by the National Science and Technology Council under Grant NSTC 113-2221-E-224-056-.
文摘To transmit customer power data collected by smart meters(SMs)to utility companies,data must first be transmitted to the corresponding data aggregation point(DAP)of the SM.The number of DAPs installed and the installation location greatly impact the whole network.For the traditional DAP placement algorithm,the number of DAPs must be set in advance,but determining the best number of DAPs is difficult,which undoubtedly reduces the overall performance of the network.Moreover,the excessive gap between the loads of different DAPs is also an important factor affecting the quality of the network.To address the above problems,this paper proposes a DAP placement algorithm,APSSA,based on the improved affinity propagation(AP)algorithm and sparrow search(SSA)algorithm,which can select the appropriate number of DAPs to be installed and the corresponding installation locations according to the number of SMs and their distribution locations in different environments.The algorithm adds an allocation mechanism to optimize the subnetwork in the SSA.APSSA is evaluated under three different areas and compared with other DAP placement algorithms.The experimental results validated that the method in this paper can reduce the network cost,shorten the average transmission distance,and reduce the load gap.
文摘Designers search for N-nodes peer-to-peer networks that can have O （1） out-degree with O （log2 N） average distance. Peer-to-peer schemes based on de Bruijn graphs are found to meet this requirement. By defining average load to evaluate the traffic load in a network, we show that in order to decrease the average load, the average distance of a network should decrease while the out-degree should increase. Especially, given out-degree k and N nodes, peer-to-peer schemes based on de Bruijn graphs have lower average load than other existing systems. The out-degree k of de Bruijn graphs should not be O（1） but should satisfy a lower bound described by an inequality κ^κ≥N^2, to ensure that the average load in peer-to-peer schemes based on de Bruijn graphs will not exceed that in Chord system.
文摘In this paper, we deduce Wiener number of some connected subgraphs in tilings (4, 4, 4, 4) and (4, 6, 12), which are in Archimedean tilings. And compute their average distance.
文摘This paper proposes a new methodology to optimize trajectory of the path for multi-robots using improved gravitational search algorithm(IGSA) in clutter environment. Classical GSA has been improved in this paper based on the communication and memory characteristics of particle swarm optimization(PSO). IGSA technique is incorporated into the multi-robot system in a dynamic framework, which will provide robust performance, self-deterministic cooperation, and coping with an inhospitable environment. The robots in the team make independent decisions, coordinate, and cooperate with each other to accomplish a common goal using the developed IGSA. A path planning scheme has been developed using IGSA to optimally obtain the succeeding positions of the robots from the existing position in the proposed environment. Finally, the analytical and experimental results of the multi-robot path planning were compared with those obtained by IGSA, GSA and differential evolution(DE) in a similar environment. The simulation and the Khepera environment result show outperforms of IGSA as compared to GSA and DE with respect to the average total trajectory path deviation, average uncovered trajectory target distance and energy optimization in terms of rotation.
文摘In this paper, we analytically discuss the scaling properties of the average square end-to-end distance < R-2 > for anisotropic random walk in D-dimensional space (D >= 2), and the returning probability P-n(r(0)) for the walker into a certain neighborhood of the origin. We will not only give the calculating formula for < R-2 > and P-n(r(0)), but also point out that if there is a symmetric axis for the distribution of the probability density of a single step displacement, we always obtain < R-perpendicular to n(2) > similar to n, where perpendicular to refers to the projections of the displacement perpendicular to each symmetric axes of the walk; in D-dimensional space with D symmetric axes perpendicular to each other, we always have < R-n(2)> similar to n and the random walk will be like a purely random motion; if the number of inter-perpendicular symmetric axis is smaller than < R-n(2)> similar to n(2) the dimensions of the space, we must have n for very large n and the walk will be like a ballistic motion. It is worth while to point out that unlike the isotropic random walk in one and two dimensions, which is certain to return into the neighborhood of the origin, generally there is only a nonzero probability for the anisotropic random walker in two dimensions to return to the neighborhood.
基金financially supported by the National Key Research and Development Program(NKRDP)projects(Grant No.2023YFD2001100)Major Science and Technology Programs in Henan Province(Grant No.221100110800)Major Science and Technology Special Project of Henan Province(Longmen Laboratory First-class Project)(Grant No.231100220200).
文摘Recognition of the boundaries of farmland plow areas has an important guiding role in the operation of intelligent agricultural equipment.To precisely recognize these boundaries,a detection method for unmanned tractor plow areas based on RGB-Depth(RGB-D)cameras was proposed,and the feasibility of the detection method was analyzed.This method applied advanced computer vision technology to the field of agricultural automation.Adopting and improving the YOLOv5-seg object segmentation algorithm,first,the Convolutional Block Attention Module(CBAM)was integrated into Concentrated-Comprehensive Convolution Block(C3)to form C3CBAM,thereby enhancing the ability of the network to extract features from plow areas.The GhostConv module was also utilized to reduce parameter and computational complexity.Second,using the depth image information provided by the RGB-D camera combined with the results recognized by the YOLOv5-seg model,the mask image was processed to extract contour boundaries,align the contours with the depth map,and obtain the boundary distance information of the plowed area.Last,based on farmland information,the calculated average boundary distance was corrected,further improving the accuracy of the distance measurements.The experiment results showed that the YOLOv5-seg object segmentation algorithm achieved a recognition accuracy of 99%for plowed areas and that the ranging accuracy improved with decreasing detection distance.The ranging error at 5.5 m was approximately 0.056 m,and the average detection time per frame is 29 ms,which can meet the real-time operational requirements.The results of this study can provide precise guarantees for the autonomous operation of unmanned plowing units.
基金the Applied and Basic Research Programs of Sichuan Science and Technology Commission(2020YJ0278).
文摘Purpose:The aim of this study is to evaluate the application value of virtual surgical planning in the management of mandibular condylar fractures and to provide a reliable reference.Methods:This was a prospective randomized controlled study and recruited 50 patients requiring surgical treatment for their mandibular condylar fractures.The inclusion criteria were patients(1)diagnosed with a condylar fracture by two clinically experienced doctors and required surgical treatment;(2)have given consent for the surgical treatment;and(3)had no contraindications to the surgery.Patients were excluded from this study if:(1)they were diagnosed with a non-dislocated or only slightly dislocated condylar fracture;(2)the comminuted condylar fracture was too severe to be treated with internal reduction and fixation;or(3)patients could not complete follow-up for 3 months.There were 33 male and 17 female patients with 33 unilateral condylar fractures and 17 bilateral condylar fractures included.The 50 patients were randomly(random number)divided into control group(25 patients with 35 sides of condylar fractures)and experimental group(25 patients with 32 sides of condylar fractures).Virtual surgical planning was used in the experimental group,but only clinical experience was used in the control group.The patients were followed up for 1,3,6 and 12 months after operation.Variables including the rate of perfect reduction by radiological analysis,the average distance of deviation between preoperative and postoperative CT measurements using Geomagic software and postoperative clinical examinations(e.g.,mouth opening,occlusion)were investigated for outcome measurement.SPSS 19 was adopted for data analysis.Results:The average operation time was 180.60 min in the experimental group and 223.2 min in the control group.One week postoperatively,CT images showed that the anatomic reduction rate was 90.63%(29/32)in the experimental group and 68.57%(24/35)in the control group,revealing significant difference(X^(2)=4.919,p=0.027).Geomagic comparative analysis revealed that the average distance of deviation was also much smaller in the experimental group than that in the control group(0.639 mm vs.0.995 mm;t=3.824,p<0.001).Conclusion:These findings suggest that virtual surgical planning can assist surgeons in surgical procedures,reduce operative time,and improve the anatomic reduction rate&accuracy,and thus of value in the diagnosis and treatment of condylar fractures.
基金Supported by the National Natural Science Foundation of China under Grant No.11471273 and No.11271307Youth Research Fund Project of Chengyi College of Jimei University under Grant No.CK17007
文摘Some physicists depicted the molecular structure SnCl_2 · 2（H_2O） by a piece of an Archimedean tiling（4.8.8） that is a partial cube. Inspired by this fact, we determine Archimedean tilings whose connected subgraphs are all partial cubes. Actually there are only four Archimedean tilings,（4.4.4.4）,（6.6.6）,（4.8.8） and（4.6.12）, which have this property. Furthermore, we obtain analytical expressions for Wiener numbers of some connected subgraphs of（4.8.8） and（4.6.12） tilings. In addition, we also discuss their asymptotic behaviors.
基金Partly supported by Grant-in-Aid for Scientific Research of the Ministry of Education,Japan,Grant No.(B)(1)-11380196
文摘Under a relatively realistic model, this paper theoretically analyzes the road traffic status inside an urban working field, including its radial roads and circular ones. Concretely, the radial and the circular average traveling distances of a car commuter in a tiny ring with wide dx are first derived, and then the necessary road area, road area rate distributions, the proportion between the radial and the circular roads to be needed are also calculated. The results presented here and the properties shown through the numerical analysis are considered to be significant at the very beginning stage of designing an urban city.
