We propose a frequency-tunable router of single photons with high routing efficiency, which is constructed by two waveguides mediately linked by a single-mode whispering gallery resonator with a driven three-level emi...We propose a frequency-tunable router of single photons with high routing efficiency, which is constructed by two waveguides mediately linked by a single-mode whispering gallery resonator with a driven three-level emitter. Quantum routing probability in the output port is obtained via the real-space Hamiltonian. By adjusting the resonator–emitter coupling and the drive, the desired continuous central frequencies for the resonance peaks of routing photons can be manipulated nearly linearly, with the assistance of Rabi splitting effect and optical Stark shift. The proposed routing system may provide potential applications in designing other frequency-modulation quantum optical devices, such as multiplexers,filters, and so on.展开更多
The ability to predict the anti-interference communications performance of unmanned aerial vehicle(UAV)data links is critical for intelligent route planning of UAVs in real combat scenarios.Previous research in this a...The ability to predict the anti-interference communications performance of unmanned aerial vehicle(UAV)data links is critical for intelligent route planning of UAVs in real combat scenarios.Previous research in this area has encountered several limitations:Classifiers exhibit low training efficiency,their precision is notably reduced when dealing with imbalanced samples,and they cannot be applied to the condition where the UAV’s flight altitude and the antenna bearing vary.This paper proposes the sequential Latin hypercube sampling(SLHS)-support vector machine(SVM)-AdaBoost algorithm,which enhances the training efficiency of the base classifier and circumvents local optima during the search process through SLHS optimization.Additionally,it mitigates the bottleneck of sample imbalance by adjusting the sample weight distribution using the AdaBoost algorithm.Through comparison,the modeling efficiency,prediction accuracy on the test set,and macro-averaged values of precision,recall,and F1-score for SLHS-SVM-AdaBoost are improved by 22.7%,5.7%,36.0%,25.0%,and 34.2%,respectively,compared with Grid-SVM.Additionally,these values are improved by 22.2%,2.1%,11.3%,2.8%,and 7.4%,respectively,compared with particle swarm optimization(PSO)-SVM-AdaBoost.Combining Latin hypercube sampling with the SLHS-SVM-AdaBoost algorithm,the classification prediction model of anti-interference performance of UAV data links,which took factors like three-dimensional position of UAV and antenna bearing into consideration,is established and used to assess the safety of the classical flying path and optimize the flying route.It was found that the risk of loss of communications could not be completely avoided by adjusting the flying altitude based on the classical path,whereas intelligent path planning based on the classification prediction model of anti-interference performance can realize complete avoidance of being interfered meanwhile reducing the route length by at least 2.3%,thus benefiting both safety and operation efficiency.展开更多
The low Earth orbit(LEO)satellite networks have outstanding advantages such as wide coverage area and not being limited by geographic environment,which can provide a broader range of communication services and has bec...The low Earth orbit(LEO)satellite networks have outstanding advantages such as wide coverage area and not being limited by geographic environment,which can provide a broader range of communication services and has become an essential supplement to the terrestrial network.However,the dynamic changes and uneven distribution of satellite network traffic inevitably bring challenges to multipath routing.Even worse,the harsh space environment often leads to incomplete collection of network state data for routing decision-making,which further complicates this challenge.To address this problem,this paper proposes a state-incomplete intelligent dynamic multipath routing algorithm(SIDMRA)to maximize network efficiency even with incomplete state data as input.Specifically,we model the multipath routing problem as a markov decision process(MDP)and then combine the deep deterministic policy gradient(DDPG)and the K shortest paths(KSP)algorithm to solve the optimal multipath routing policy.We use the temporal correlation of the satellite network state to fit the incomplete state data and then use the message passing neuron network(MPNN)for data enhancement.Simulation results show that the proposed algorithm outperforms baseline algorithms regarding average end-to-end delay and packet loss rate and performs stably under certain missing rates of state data.展开更多
The GIS technique is used for airport surface management to study the optimization of airplane taxiway for arrival and departure flights. The shortest paths are designed for just-arrived and ready-for-departing flight...The GIS technique is used for airport surface management to study the optimization of airplane taxiway for arrival and departure flights. The shortest paths are designed for just-arrived and ready-for-departing flights of the airport. Additionally, whether the flights could confront each other head-to-head on the taxiway is judged. In regard to the airport′s security and efficiency, airplanes must continuously taxi along the shortest route and the head-to-head confrontation should not occur. Two schemes are designed: One is to change the taxiing velocity of arrival flights, the other is to delay the starting time of departure flights. This algorithm is approved by a practical example.展开更多
The air route network, which supports all the flight activities of the civil aviation, is the most fundamental infrastructure of air traffic management system. In this paper, we study the Chinese air route network （C...The air route network, which supports all the flight activities of the civil aviation, is the most fundamental infrastructure of air traffic management system. In this paper, we study the Chinese air route network （CARN） within the framework of complex networks. We find that CARN is a geographical network possessing exponential degree distribution, low clustering coefficient, large shortest path length and exponential spatial distance distribution that is obviously different from that of the Chinese airport network （CAN）. Besides, via investigating the flight data from 2002 to 2010, we demonstrate that the topology structure of CARN is homogeneous, howbeit the distribution of flight flow on CARN is rather heterogeneous. In addition, the traffic on CARN keeps growing in an exponential form and the increasing speed of west China is remarkably larger than that of east China. Our work will be helpful to better understand Chinese air traffic systems.展开更多
Air route network(ARN)planning is an efficient way to alleviate civil aviation flight delays caused by increasing development and pressure for safe operation.Here,the ARN shortest path was taken as the objective funct...Air route network(ARN)planning is an efficient way to alleviate civil aviation flight delays caused by increasing development and pressure for safe operation.Here,the ARN shortest path was taken as the objective function,and an air route network node(ARNN)optimization model was developed to circumvent the restrictions imposed by″three areas″,also known as prohibited areas,restricted areas,and dangerous areas(PRDs),by creating agrid environment.And finally the objective function was solved by means of an adaptive ant colony algorithm(AACA).The A593,A470,B221,and G204 air routes in the busy ZSHA flight information region,where the airspace includes areas with different levels of PRDs,were taken as an example.Based on current flight patterns,a layout optimization of the ARNN was computed using this model and algorithm and successfully avoided PRDs.The optimized result reduced the total length of routes by 2.14% and the total cost by 9.875%.展开更多
As an industrial byproduct of oil refining,furfural extract oil from reduced-pressure route Ⅱ with high aromatic content was used to prepare heat-resistant condensed polynuclear aromatic（COPNA） resin for the first ...As an industrial byproduct of oil refining,furfural extract oil from reduced-pressure route Ⅱ with high aromatic content was used to prepare heat-resistant condensed polynuclear aromatic（COPNA） resin for the first time.The basic properties of furfural extract oil and the resultant COPNA resin were characterized by infrared spectroscopy（FT-IR）,nuclear magnetic resonance spectroscopy（1H-NMR）,thermogravimetric analysis（TGA） and elemental analysis（EA）.The result showed that heat treated furfural extract oil was successfully used for the synthesis of heat-resistant COPNA resin.The average structural parameters of raw materials and prepared resin were calculated by the improved Brown-Ladner method,and the averaged molecular structure of the resin was obtained.The reaction mechanism for the synthesis of COPNA resin was suggested as an acid-catalyzed positive ion type polymerization.展开更多
As a nanometer-level interconnection,the Optical Network-on-Chip(ONoC)was proposed since it was typically characterized by low latency,high bandwidth and power efficiency. Compared with a 2-Dimensional(2D)design,the 3...As a nanometer-level interconnection,the Optical Network-on-Chip(ONoC)was proposed since it was typically characterized by low latency,high bandwidth and power efficiency. Compared with a 2-Dimensional(2D)design,the 3D integration has the higher packing density and the shorter wire length. Therefore,the 3D ONoC will have the great potential in the future. In this paper,we first discuss the existing ONoC researches,and then design mesh and torus ONoCs from the perspectives of topology,router,and routing module,with the help of 3D integration. A simulation platform is established by using OPNET to compare the performance of 2D and 3D ONoCs in terms of average delay and packet loss rate. The performance comparison between 3D mesh and 3D torus ONoCs is also conducted. The simulation results demonstrate that 3D integration has the advantage of reducing average delay and packet loss rate,and 3D torus ONoC has the better performance compared with 3D mesh solution. Finally,we summarize some future challenges with possible solutions,including microcosmic routing inside optical routers and highly-efficient traffic grooming.展开更多
In order to improve safety,economy efficiency and design automation degree of air route in terminal airspace,Three-dimensional(3D)planning of routes network is investigated.A waypoint probability search method is prop...In order to improve safety,economy efficiency and design automation degree of air route in terminal airspace,Three-dimensional(3D)planning of routes network is investigated.A waypoint probability search method is proposed to optimize individual flight path.Through updating horizontal pheromones by negative feedback factors,an antcolony algorithm of path searching in 3Dterminal airspace is implemented.The principle of optimization sequence of arrival and departure routes is analyzed.Each route is optimized successively,and the overall optimization of the whole route network is finally achieved.A case study shows that it takes about 63 sto optimize 8arrival and departure routes,and the operation efficiency can be significantly improved with desirable safety and economy.展开更多
Background:Many healthcare workers were infected by coronavirus disease 2019(COVID-19)early in the epidemic posing a big challenge for epidemic control.Hence,this study aims to explore perceived infection routes,influ...Background:Many healthcare workers were infected by coronavirus disease 2019(COVID-19)early in the epidemic posing a big challenge for epidemic control.Hence,this study aims to explore perceived infection routes,influencing factors,psychosocial changes,and management procedures for COVID-19 infected healthcare workers.Methods:This is a cross-sectional,single hospital-based study.We recruited all 105 confirmed COVID-19 healthcare workers in the Zhongnan Hospital of Wuhan University from February 15 to 29,2020.All participants completed a validated questionnaire.Electronic consent was obtained from all participants.Perceived causes of infection,infection prevention,control knowledge and behaviour,psychological changes,symptoms and treatment were measured.Results:Finally,103 professional staff with COVID-19 finished the questionnaire and was included(response rate:98.1%).Of them,87 cases(84.5%)thought they were infected in working environment in hospital,one(1.0%)thought their infection was due to the laboratory environment,and 5(4.9%)thought they were infected in daily life or community environment.Swab of throat collection and physical examination were the procedures perceived as most likely causing their infection by nurses and doctors respectively.Forty-three(41.8%)thought their infection was related to protective equipment,utilization of common equipment(masks and gloves).The top three first symptoms displayed before diagnosis were fever(41.8%),lethargy(33.0%)and muscle aches(30.1%).After diagnosis,88.3%staff experienced psychological stress or emotional changes during their isolation period,only 11.7%had almost no emotional changes.Arbidol(Umifenovir;an anti-influza drug;69.2%)was the drug most commonly used to target infection in mild and moderate symptoms.Conclusion:The main perceived mode of transmission was not maintaining protection when working at a close distance and having intimate contact with infected cases.Positive psychological intervention is necessary.展开更多
This paper describes route designs and cost estimation for possible interconnections between Japan-Russia and between Japan-South Korea based on the Asia International Grid Connection Study Group 2^(nd) report. The Gr...This paper describes route designs and cost estimation for possible interconnections between Japan-Russia and between Japan-South Korea based on the Asia International Grid Connection Study Group 2^(nd) report. The Group has conducted a desktop study to design several cable routes as possible options. To optimize the route, the group studied a wide range of open data, regarding sea depth, fishery zones, geographic condition, available transmission capacity in connecting points inside Japan and so on. The result of desktop study shows that it is possible to keep sea depth for planned routes less than 300 m and length for most of designed routes is less than 600 km. Compare to existing undersea cables in Europe, proposed routes are not challenging from technical and geological viewpoints.The study shows that investment cost range, including cost for grid enhancement inside Japan, is from around 200 bn JPY to 600 bn JPY, depending on the routes. Annualized cost range is from around 8 to 24 bn JPY(for 25-year operation), which is not so large compare to 1800 bn JPY-average annual investment in transmission infrastructure by 10 power utilities in the past 23 years.展开更多
This paper presents a novel energy-aware algorithm for service composition based on sharing routes in Wireless Sensor Networks (WSNs). The method integrates the resource of the overlapping WSNs to a virtual resource p...This paper presents a novel energy-aware algorithm for service composition based on sharing routes in Wireless Sensor Networks (WSNs). The method integrates the resource of the overlapping WSNs to a virtual resource pool in the execution cycles of the workflow. This approach chooses the suitable service instances according to the current execution environment and user requirements with minimum energy consumption. Finally, the performance of sharing routes service composition selection in WSNs has been evaluated.展开更多
Cognitive radio networks(CRNs) are expected to improve spectrum utilization efficiently by allowing secondary users(SUs) to opportunistically access the licensed spectrum of primary users(PUs).In CRNs,source and desti...Cognitive radio networks(CRNs) are expected to improve spectrum utilization efficiently by allowing secondary users(SUs) to opportunistically access the licensed spectrum of primary users(PUs).In CRNs,source and destination SUs may achieve information interaction in an ad hoc manner.In the case that no direct transmission link between the SU transmission pairs is available,multi-hop relay SUs can be applied to forward information for the source and destination SUs,resulting in multi-hop CRNs.In this paper,we consider a multi-hop CRN consisting of multiple PUs,SU transmission pairs and relay SUs.Stressing the importance of transmission hops and the tradeoff between data rate and power consumption,we propose an energy efficient constrained shortest path first(CSPF)-based joint resource allocation and route selection algorithm,which consists of two sub-algorithms,i.e.,CSPF-based route selection sub-algorithm and energy efficient resource allocation sub-algorithm.More specifically,we first apply CSPF-based route selection sub-algorithm to obtain the shortest candidate routes(SCRs) between the SU pair under the transmission constraints.Then,an energy efficient resource allocation problem of the SCRs is formulated and solved by applying iterative algorithm and Lagrange dual method.Simu-lation results demonstrate the effectiveness of the proposed algorithm.展开更多
Intelligent and connected vehicles have leveraged edge computing paradigm to enhance their environment comprehension and behavior planning capabilities.As the quantity of intelligent vehicles and the demand for edge c...Intelligent and connected vehicles have leveraged edge computing paradigm to enhance their environment comprehension and behavior planning capabilities.As the quantity of intelligent vehicles and the demand for edge computing are increasing rapidly,it becomes critical to efficiently orchestrate the communication and computation resources on edge clouds.Existing methods usually perform resource allocation in a fairly effective but still reactive manner,which is subject to the capacity of nearby edge clouds.To deal with the contradiction between the spatiotemporally varying demands for edge computing and the fixed edge cloud capacity,we proactively balance the edge computing demands across edge clouds by appropriate route planning.In this paper,route planning and resource allocation are jointly optimized to enhance intelligent driving.We propose a multi-scale decentralized optimization method to deal with the curse of dimensionality.In large-scale optimization,backpressure algorithm is used to conduct route planning and load balancing across edge clouds.In small-scale optimization,game-theoretic multi-agent learning is exploited to perform regional resource allocation.The experimental results show that the proposed algorithm outperforms the baseline algorithms which optimize route planning and resource allocation separately.展开更多
In order to solve cruise missile route planning problem for low-altitude penetration , a hy- brid particle swarm optimization （ HPSO ） algorithm is proposed. Firstly, K-means clustering algo- rithm is applied to div...In order to solve cruise missile route planning problem for low-altitude penetration , a hy- brid particle swarm optimization （ HPSO ） algorithm is proposed. Firstly, K-means clustering algo- rithm is applied to divide the particle swarm into multiple isolated sub-populations, then niche algo- rithm is adopted to make all particles independently search for optimal values in their own sub-popu- lations. Finally simulated annealing （SA） algorithm is introduced to avoid the weakness of PSO algo- rithm, which can easily be trapped into the local optimum in the search process. The optimal value obtained by every sub-population search corresponds to an optimal route, multiple different optimal routes are provided for cruise missile. Simulation results show that the HPSO algorithm has a fast convergence rate, and the planned routes have flat ballisticpaths and short ranges which meet the low-altitude penetration requirements.展开更多
For an electronic chart display and information system (ECDIS), the most important function is the route design. In this paper, a novel approach to developing ECDIS was given and then an effective method was proposed ...For an electronic chart display and information system (ECDIS), the most important function is the route design. In this paper, a novel approach to developing ECDIS was given and then an effective method was proposed for route design and automatic check. The mathematical model and logical relationship for coordinate transformation were also provided. They were adopted in ECDIS developing, which was based on the researeh of the Vxworks real-time operating system. The actual system application implies that the method is practical and can help navigation very well.展开更多
Containership stowage plans are a pivotal teaches in the system of container transportation.With the increasing containers shipping,planning containership stowage has become more and more complicated.So intelligent st...Containership stowage plans are a pivotal teaches in the system of container transportation.With the increasing containers shipping,planning containership stowage has become more and more complicated.So intelligent stowage planning for containerships is of great significance.An effective stowage plan may improve efficiency of transportation system.First,the progress of containership stowage plan at home and abroad is reviewed,including the latest developments,such as the application of various optimization methods and computer techniques to the problem.Then,the complexities of the problem are discussed and areas where investigations are still needed are pointed out.This will provide a reference for further research on the subject.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 12365003, 12364024, and 11864014)the Natural Science Foundation of Jiangxi Province, China (Grant Nos. 20212BAB201014 and 20224BAB201023)。
文摘We propose a frequency-tunable router of single photons with high routing efficiency, which is constructed by two waveguides mediately linked by a single-mode whispering gallery resonator with a driven three-level emitter. Quantum routing probability in the output port is obtained via the real-space Hamiltonian. By adjusting the resonator–emitter coupling and the drive, the desired continuous central frequencies for the resonance peaks of routing photons can be manipulated nearly linearly, with the assistance of Rabi splitting effect and optical Stark shift. The proposed routing system may provide potential applications in designing other frequency-modulation quantum optical devices, such as multiplexers,filters, and so on.
文摘The ability to predict the anti-interference communications performance of unmanned aerial vehicle(UAV)data links is critical for intelligent route planning of UAVs in real combat scenarios.Previous research in this area has encountered several limitations:Classifiers exhibit low training efficiency,their precision is notably reduced when dealing with imbalanced samples,and they cannot be applied to the condition where the UAV’s flight altitude and the antenna bearing vary.This paper proposes the sequential Latin hypercube sampling(SLHS)-support vector machine(SVM)-AdaBoost algorithm,which enhances the training efficiency of the base classifier and circumvents local optima during the search process through SLHS optimization.Additionally,it mitigates the bottleneck of sample imbalance by adjusting the sample weight distribution using the AdaBoost algorithm.Through comparison,the modeling efficiency,prediction accuracy on the test set,and macro-averaged values of precision,recall,and F1-score for SLHS-SVM-AdaBoost are improved by 22.7%,5.7%,36.0%,25.0%,and 34.2%,respectively,compared with Grid-SVM.Additionally,these values are improved by 22.2%,2.1%,11.3%,2.8%,and 7.4%,respectively,compared with particle swarm optimization(PSO)-SVM-AdaBoost.Combining Latin hypercube sampling with the SLHS-SVM-AdaBoost algorithm,the classification prediction model of anti-interference performance of UAV data links,which took factors like three-dimensional position of UAV and antenna bearing into consideration,is established and used to assess the safety of the classical flying path and optimize the flying route.It was found that the risk of loss of communications could not be completely avoided by adjusting the flying altitude based on the classical path,whereas intelligent path planning based on the classification prediction model of anti-interference performance can realize complete avoidance of being interfered meanwhile reducing the route length by at least 2.3%,thus benefiting both safety and operation efficiency.
文摘The low Earth orbit(LEO)satellite networks have outstanding advantages such as wide coverage area and not being limited by geographic environment,which can provide a broader range of communication services and has become an essential supplement to the terrestrial network.However,the dynamic changes and uneven distribution of satellite network traffic inevitably bring challenges to multipath routing.Even worse,the harsh space environment often leads to incomplete collection of network state data for routing decision-making,which further complicates this challenge.To address this problem,this paper proposes a state-incomplete intelligent dynamic multipath routing algorithm(SIDMRA)to maximize network efficiency even with incomplete state data as input.Specifically,we model the multipath routing problem as a markov decision process(MDP)and then combine the deep deterministic policy gradient(DDPG)and the K shortest paths(KSP)algorithm to solve the optimal multipath routing policy.We use the temporal correlation of the satellite network state to fit the incomplete state data and then use the message passing neuron network(MPNN)for data enhancement.Simulation results show that the proposed algorithm outperforms baseline algorithms regarding average end-to-end delay and packet loss rate and performs stably under certain missing rates of state data.
文摘The GIS technique is used for airport surface management to study the optimization of airplane taxiway for arrival and departure flights. The shortest paths are designed for just-arrived and ready-for-departing flights of the airport. Additionally, whether the flights could confront each other head-to-head on the taxiway is judged. In regard to the airport′s security and efficiency, airplanes must continuously taxi along the shortest route and the head-to-head confrontation should not occur. Two schemes are designed: One is to change the taxiing velocity of arrival flights, the other is to delay the starting time of departure flights. This algorithm is approved by a practical example.
基金supported by the National Basic Research Program of China (Grant No.2011CB707004)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China (Grant No.60921001)+1 种基金the National Key Technologies R & D Program of China (Grant No.2011BAH24B02)the Fundamental Research Funds for the Central Universities
文摘The air route network, which supports all the flight activities of the civil aviation, is the most fundamental infrastructure of air traffic management system. In this paper, we study the Chinese air route network （CARN） within the framework of complex networks. We find that CARN is a geographical network possessing exponential degree distribution, low clustering coefficient, large shortest path length and exponential spatial distance distribution that is obviously different from that of the Chinese airport network （CAN）. Besides, via investigating the flight data from 2002 to 2010, we demonstrate that the topology structure of CARN is homogeneous, howbeit the distribution of flight flow on CARN is rather heterogeneous. In addition, the traffic on CARN keeps growing in an exponential form and the increasing speed of west China is remarkably larger than that of east China. Our work will be helpful to better understand Chinese air traffic systems.
基金supported by the the Youth Science and Technology Innovation Fund (Science)(Nos.NS2014070, NS2014070)
文摘Air route network(ARN)planning is an efficient way to alleviate civil aviation flight delays caused by increasing development and pressure for safe operation.Here,the ARN shortest path was taken as the objective function,and an air route network node(ARNN)optimization model was developed to circumvent the restrictions imposed by″three areas″,also known as prohibited areas,restricted areas,and dangerous areas(PRDs),by creating agrid environment.And finally the objective function was solved by means of an adaptive ant colony algorithm(AACA).The A593,A470,B221,and G204 air routes in the busy ZSHA flight information region,where the airspace includes areas with different levels of PRDs,were taken as an example.Based on current flight patterns,a layout optimization of the ARNN was computed using this model and algorithm and successfully avoided PRDs.The optimized result reduced the total length of routes by 2.14% and the total cost by 9.875%.
基金financially supported by the National Natural Science Foundation of China (Nos. 20876176, 51172285, 51372277)the Natural Science Foundation of Shandong Province (ZR2011EL030)the Fundamental Research Funds for the Central Universities (14CX02060A)
文摘As an industrial byproduct of oil refining,furfural extract oil from reduced-pressure route Ⅱ with high aromatic content was used to prepare heat-resistant condensed polynuclear aromatic（COPNA） resin for the first time.The basic properties of furfural extract oil and the resultant COPNA resin were characterized by infrared spectroscopy（FT-IR）,nuclear magnetic resonance spectroscopy（1H-NMR）,thermogravimetric analysis（TGA） and elemental analysis（EA）.The result showed that heat treated furfural extract oil was successfully used for the synthesis of heat-resistant COPNA resin.The average structural parameters of raw materials and prepared resin were calculated by the improved Brown-Ladner method,and the averaged molecular structure of the resin was obtained.The reaction mechanism for the synthesis of COPNA resin was suggested as an acid-catalyzed positive ion type polymerization.
基金supported in part by the National Nat-ural Science Foundation of China(Grant Nos.61401082,61471109,61502075,61672123,91438110,U1301253)the Fundamental Research Funds for Central Universities(Grant Nos.N161604004,N161608001,N150401002,DUT15RC(3)009)Liaoning Bai Qian Wan Talents Program,and National High-Level Personnel Special Support Program for Youth Top-Notch Talent
文摘As a nanometer-level interconnection,the Optical Network-on-Chip(ONoC)was proposed since it was typically characterized by low latency,high bandwidth and power efficiency. Compared with a 2-Dimensional(2D)design,the 3D integration has the higher packing density and the shorter wire length. Therefore,the 3D ONoC will have the great potential in the future. In this paper,we first discuss the existing ONoC researches,and then design mesh and torus ONoCs from the perspectives of topology,router,and routing module,with the help of 3D integration. A simulation platform is established by using OPNET to compare the performance of 2D and 3D ONoCs in terms of average delay and packet loss rate. The performance comparison between 3D mesh and 3D torus ONoCs is also conducted. The simulation results demonstrate that 3D integration has the advantage of reducing average delay and packet loss rate,and 3D torus ONoC has the better performance compared with 3D mesh solution. Finally,we summarize some future challenges with possible solutions,including microcosmic routing inside optical routers and highly-efficient traffic grooming.
基金supported by the National Natural Science Foundation of China(No.61039001)the State Technology Supporting Plan(No.2011BAH24B08)the Fundamental Research Funds for the Central Universities (No.ZXH2011A002)
文摘In order to improve safety,economy efficiency and design automation degree of air route in terminal airspace,Three-dimensional(3D)planning of routes network is investigated.A waypoint probability search method is proposed to optimize individual flight path.Through updating horizontal pheromones by negative feedback factors,an antcolony algorithm of path searching in 3Dterminal airspace is implemented.The principle of optimization sequence of arrival and departure routes is analyzed.Each route is optimized successively,and the overall optimization of the whole route network is finally achieved.A case study shows that it takes about 63 sto optimize 8arrival and departure routes,and the operation efficiency can be significantly improved with desirable safety and economy.
基金supported by the Emergency Science and Technology Project in Hubei Province(2020FCA008)
文摘Background:Many healthcare workers were infected by coronavirus disease 2019(COVID-19)early in the epidemic posing a big challenge for epidemic control.Hence,this study aims to explore perceived infection routes,influencing factors,psychosocial changes,and management procedures for COVID-19 infected healthcare workers.Methods:This is a cross-sectional,single hospital-based study.We recruited all 105 confirmed COVID-19 healthcare workers in the Zhongnan Hospital of Wuhan University from February 15 to 29,2020.All participants completed a validated questionnaire.Electronic consent was obtained from all participants.Perceived causes of infection,infection prevention,control knowledge and behaviour,psychological changes,symptoms and treatment were measured.Results:Finally,103 professional staff with COVID-19 finished the questionnaire and was included(response rate:98.1%).Of them,87 cases(84.5%)thought they were infected in working environment in hospital,one(1.0%)thought their infection was due to the laboratory environment,and 5(4.9%)thought they were infected in daily life or community environment.Swab of throat collection and physical examination were the procedures perceived as most likely causing their infection by nurses and doctors respectively.Forty-three(41.8%)thought their infection was related to protective equipment,utilization of common equipment(masks and gloves).The top three first symptoms displayed before diagnosis were fever(41.8%),lethargy(33.0%)and muscle aches(30.1%).After diagnosis,88.3%staff experienced psychological stress or emotional changes during their isolation period,only 11.7%had almost no emotional changes.Arbidol(Umifenovir;an anti-influza drug;69.2%)was the drug most commonly used to target infection in mild and moderate symptoms.Conclusion:The main perceived mode of transmission was not maintaining protection when working at a close distance and having intimate contact with infected cases.Positive psychological intervention is necessary.
文摘This paper describes route designs and cost estimation for possible interconnections between Japan-Russia and between Japan-South Korea based on the Asia International Grid Connection Study Group 2^(nd) report. The Group has conducted a desktop study to design several cable routes as possible options. To optimize the route, the group studied a wide range of open data, regarding sea depth, fishery zones, geographic condition, available transmission capacity in connecting points inside Japan and so on. The result of desktop study shows that it is possible to keep sea depth for planned routes less than 300 m and length for most of designed routes is less than 600 km. Compare to existing undersea cables in Europe, proposed routes are not challenging from technical and geological viewpoints.The study shows that investment cost range, including cost for grid enhancement inside Japan, is from around 200 bn JPY to 600 bn JPY, depending on the routes. Annualized cost range is from around 8 to 24 bn JPY(for 25-year operation), which is not so large compare to 1800 bn JPY-average annual investment in transmission infrastructure by 10 power utilities in the past 23 years.
基金supported by National Natural Science Foundation of China under Grant No. 60833002Natural Science Foundation of Beijing under Grant No.4091003Foundation Sciences of Beijing Jiaotong University under Grant No.2011YJS014
文摘This paper presents a novel energy-aware algorithm for service composition based on sharing routes in Wireless Sensor Networks (WSNs). The method integrates the resource of the overlapping WSNs to a virtual resource pool in the execution cycles of the workflow. This approach chooses the suitable service instances according to the current execution environment and user requirements with minimum energy consumption. Finally, the performance of sharing routes service composition selection in WSNs has been evaluated.
基金supported by the National Science and Technology Specific Project of China(2016ZX03001010-004)National Natural Science Foundation of China(6140105361571073)+2 种基金the Joint Scientifi c Research Fund Ministry of Education and China Mobile(MCM20160105)the special fund of Chongqing key laboratory(CSTC)the project of Chongqing Municipal Education Commission(Kjzh11206)
文摘Cognitive radio networks(CRNs) are expected to improve spectrum utilization efficiently by allowing secondary users(SUs) to opportunistically access the licensed spectrum of primary users(PUs).In CRNs,source and destination SUs may achieve information interaction in an ad hoc manner.In the case that no direct transmission link between the SU transmission pairs is available,multi-hop relay SUs can be applied to forward information for the source and destination SUs,resulting in multi-hop CRNs.In this paper,we consider a multi-hop CRN consisting of multiple PUs,SU transmission pairs and relay SUs.Stressing the importance of transmission hops and the tradeoff between data rate and power consumption,we propose an energy efficient constrained shortest path first(CSPF)-based joint resource allocation and route selection algorithm,which consists of two sub-algorithms,i.e.,CSPF-based route selection sub-algorithm and energy efficient resource allocation sub-algorithm.More specifically,we first apply CSPF-based route selection sub-algorithm to obtain the shortest candidate routes(SCRs) between the SU pair under the transmission constraints.Then,an energy efficient resource allocation problem of the SCRs is formulated and solved by applying iterative algorithm and Lagrange dual method.Simu-lation results demonstrate the effectiveness of the proposed algorithm.
基金supported in part by the Natural Science Foundation of China under Grant 61902035 and Grant 61876023in part by the Natural Science Foundation of Shandong Province of China under Grant ZR2020LZH005in part by China Postdoctoral Science Foundation under Grant 2019M660565.
文摘Intelligent and connected vehicles have leveraged edge computing paradigm to enhance their environment comprehension and behavior planning capabilities.As the quantity of intelligent vehicles and the demand for edge computing are increasing rapidly,it becomes critical to efficiently orchestrate the communication and computation resources on edge clouds.Existing methods usually perform resource allocation in a fairly effective but still reactive manner,which is subject to the capacity of nearby edge clouds.To deal with the contradiction between the spatiotemporally varying demands for edge computing and the fixed edge cloud capacity,we proactively balance the edge computing demands across edge clouds by appropriate route planning.In this paper,route planning and resource allocation are jointly optimized to enhance intelligent driving.We propose a multi-scale decentralized optimization method to deal with the curse of dimensionality.In large-scale optimization,backpressure algorithm is used to conduct route planning and load balancing across edge clouds.In small-scale optimization,game-theoretic multi-agent learning is exploited to perform regional resource allocation.The experimental results show that the proposed algorithm outperforms the baseline algorithms which optimize route planning and resource allocation separately.
基金Supported by the National Natural Science Foundation of China(91016004)
文摘In order to solve cruise missile route planning problem for low-altitude penetration , a hy- brid particle swarm optimization （ HPSO ） algorithm is proposed. Firstly, K-means clustering algo- rithm is applied to divide the particle swarm into multiple isolated sub-populations, then niche algo- rithm is adopted to make all particles independently search for optimal values in their own sub-popu- lations. Finally simulated annealing （SA） algorithm is introduced to avoid the weakness of PSO algo- rithm, which can easily be trapped into the local optimum in the search process. The optimal value obtained by every sub-population search corresponds to an optimal route, multiple different optimal routes are provided for cruise missile. Simulation results show that the HPSO algorithm has a fast convergence rate, and the planned routes have flat ballisticpaths and short ranges which meet the low-altitude penetration requirements.
文摘For an electronic chart display and information system (ECDIS), the most important function is the route design. In this paper, a novel approach to developing ECDIS was given and then an effective method was proposed for route design and automatic check. The mathematical model and logical relationship for coordinate transformation were also provided. They were adopted in ECDIS developing, which was based on the researeh of the Vxworks real-time operating system. The actual system application implies that the method is practical and can help navigation very well.
基金Supported by High-tech Research of Educational Department of Liaoning Province (No.05L091)a Special Fund Support Item of Doctor Subject of Colleges and Universities(No.2000014125)
文摘Containership stowage plans are a pivotal teaches in the system of container transportation.With the increasing containers shipping,planning containership stowage has become more and more complicated.So intelligent stowage planning for containerships is of great significance.An effective stowage plan may improve efficiency of transportation system.First,the progress of containership stowage plan at home and abroad is reviewed,including the latest developments,such as the application of various optimization methods and computer techniques to the problem.Then,the complexities of the problem are discussed and areas where investigations are still needed are pointed out.This will provide a reference for further research on the subject.
