In 6G era,service forms in which computing power acts as the core will be ubiquitous in the network.At the same time,the collaboration among edge computing,cloud computing and network is needed to support edge computi...In 6G era,service forms in which computing power acts as the core will be ubiquitous in the network.At the same time,the collaboration among edge computing,cloud computing and network is needed to support edge computing service with strong demand for computing power,so as to realize the optimization of resource utilization.Based on this,the article discusses the research background,key techniques and main application scenarios of computing power network.Through the demonstration,it can be concluded that the technical solution of computing power network can effectively meet the multi-level deployment and flexible scheduling needs of the future 6G business for computing,storage and network,and adapt to the integration needs of computing power and network in various scenarios,such as user oriented,government enterprise oriented,computing power open and so on.展开更多
Indoor positioning systems have been sufficiently researched to provide location information of persons and devices.This paper is focused on the current research and further development of indoor positioning.The stand...Indoor positioning systems have been sufficiently researched to provide location information of persons and devices.This paper is focused on the current research and further development of indoor positioning.The standard evolution and industry development are summarized.There are various positioning systems according to the scenarios,cost and accuracy.However,there is a basic positioning system framework including information extraction,measurement and calculation.In particular,the detailed positioning technologies mainly including cellular positioning and Local Area Network(LAN) positioning are listed and compared to provide a reference for practical applications.Finally,we summarize the challenges of indoor positioning and give a3-phase evolution route.展开更多
To solve the contradiction between the increasing demand of diverse vehicular wireless applications and the shortage of spectrum resource, a novel cognitive cooperative vehicular ad-hoc network （CC- VANET） framework...To solve the contradiction between the increasing demand of diverse vehicular wireless applications and the shortage of spectrum resource, a novel cognitive cooperative vehicular ad-hoc network （CC- VANET） framework is proposed in this paper. Firstly, we develop an adaptive cognitive spectrum sensing （ACSS） mechanism which can help to trigger and adjust the spectrum sensing window according to network traffic load status and communication quality. And then, Generalized Nash Bargaining SoLution （GNBS）, which can achieve a good tradeoff between efficiency and weighted fairness, is proposed to formulate the asymmetric inter- cell resource allocation. Finally, GNBS- Safety （GNBS-S） scheme is developed to enhance the Quality of Service （QoS） of safety applications, especially in the heavy load status, where the bandwidth demanded and supplied cannot be matched well. Furthermore, the primary user activity （PUA） which can cause rate loss to secondary users, is also considered to alleviate its influence to fairness. Simulation results indicate that the proposed CC-VANET scheme can greatly improve the spectrum efficiency and reduce the transmission delay and packet loss rate on the heavy contention status. And GNBS spectrum allocation scheme outperforms both the Max-rain and Max-rate schemes, and canenhance the communication reliability of safety service considerably in CC-VANET.展开更多
Resource allocation is crucial for satellite networks. In this paper, we propose a multi-resource fair allocation scheme, namely Dominant and Max-min Fair(DMMF), to efficiently and fairly allocate resources. It consis...Resource allocation is crucial for satellite networks. In this paper, we propose a multi-resource fair allocation scheme, namely Dominant and Max-min Fair(DMMF), to efficiently and fairly allocate resources. It consists of two allocation stages, dominant resource fair(DRF) allocation stage and max-min fairness(MMF) allocation stage. The proposed DMMF scheme exhibits desirable properties, including share incentive, strategy proofness, envy freeness and Pareto optimality. Meanwhile, DMMF can improve the allocation efficiency and reach 100% allocation efficiency.展开更多
With the popularity of smart handheld devices, mobile streaming video has multiplied the global network traffic in recent years. A huge concern of users' quality of experience(Qo E) has made rate adaptation method...With the popularity of smart handheld devices, mobile streaming video has multiplied the global network traffic in recent years. A huge concern of users' quality of experience(Qo E) has made rate adaptation methods very attractive. In this paper, we propose a two-phase rate adaptation strategy to improve users' real-time video Qo E. First, to measure and assess video Qo E, we provide a continuous Qo E prediction engine modeled by RNN recurrent neural network. Different from traditional Qo E models which consider the Qo E-aware factors separately or incompletely, our RNN-Qo E model accounts for three descriptive factors(video quality, rebuffering, and rate change) and reflects the impact of cognitive memory and recency. Besides, the video playing is separated into the initial startup phase and the steady playback phase, and we takes different optimization goals for each phase: the former aims at shortening the startup delay while the latter ameliorates the video quality and the rebufferings. Simulation results have shown that RNN-Qo E can follow the subjective Qo E quite well, and the proposed strategy can effectively reduce the occurrence of rebufferings caused by the mismatch between the requested video rates and the fluctuated throughput and attains standout performance on real-time Qo E compared with classical rate adaption methods.展开更多
A forest fire is a severe threat to forest resources and human life, In this paper, we propose a forest-fire detection system that has an artificial neural network algorithm implemented in a wireless sensor network （...A forest fire is a severe threat to forest resources and human life, In this paper, we propose a forest-fire detection system that has an artificial neural network algorithm implemented in a wireless sensor network （WSN）. The proposed detection system mitigates the threat of forest fires by provide accurate fire alarm with low maintenance cost. The accuracy is increased by the novel multi- criteria detection, referred to as an alarm decision depends on multiple attributes of a forest fire. The multi-criteria detection is implemented by the artificial neural network algorithm. Meanwhile, we have developed a prototype of the proposed system consisting of the solar batter module, the fire detection module and the user interface module.展开更多
Understanding cardiac blood flow behaviors is of importance for cardiovascular research and clinical assessment of ventricle functions.Patient-specific Echo-based left ventricle(LV)fluid-structure interaction(FSI)mode...Understanding cardiac blood flow behaviors is of importance for cardiovascular research and clinical assessment of ventricle functions.Patient-specific Echo-based left ventricle(LV)fluid-structure interaction(FSI)models were introduced to perform ventricle mechanical analysis,investigate flow behaviors,and evaluate the impact of myocardial infarction(MI)and hypertension on blood flow in the LV.Echo image data were acquired from 3 patients with consent obtained:one healthy volunteer(P1),one hypertension patient(P2),and one patient who had an inferior and posterior myocardial infarction(P3).The nonlinear Mooney-Rivlin model was used for ventricle tissue with material parameter values chosen to match echo-measure LV volume data.Using the healthy case as baseline,LV with MI had lower peak flow velocity(30%lower at beginejection)and hypertension LV had higher peak flow velocity(16%higher at begin-filling).The vortex area(defined as the area with vorticity>0)for P3 was 19%smaller than that of P1.The vortex area for P2 was 12%smaller than that of P1.At peak of filling,the maximum flow shear stress(FSS)for P2 and P3 were 390%higher and 63%lower than that of P1,respectively.Meanwhile,LV stress and strain of P2 were 41%and 15%higher than those of P1,respectively.LV stress and strain of P3 were 36%and 42%lower than those of P1,respectively.In conclusion,FSI models could provide both flow and structural stress/strain information which would serve as the base for further cardiovascular investigations related to disease initiation,progression,and treatment strategy selections.Large-scale studies are needed to validate our findings.展开更多
Plaque erosion,together with plaque rupture,is a common cause for acute coronary syndrome(ACS).Plaque erosion alone is responsible for about one third of the patients with ACS.Eroded plaque is defined as thrombosed,en...Plaque erosion,together with plaque rupture,is a common cause for acute coronary syndrome(ACS).Plaque erosion alone is responsible for about one third of the patients with ACS.Eroded plaque is defined as thrombosed,endothelium-absent and non-ruptured but often-inflamed plaques based on histological findings.Even though there is efficient imaging technologies to detect the eroded plaque in vivo and tailored treatment strategy has also been developed for ACScaused by erosion in clinics,the pathogenesis mechanisms that cause plaque erosion are not fully understood.It is widely postulated that thrombus formation and endothelial apoptosis(the precursors of plaque erosion)have closed association with biomechanical conditions in the coronary vessel.Revealing of the mechanical conditions in the eroded plaque could advance our knowledge in understanding the formation of plaque erosion.To this end,patient-specific OCT-based fluid-structure interaction(FSI)models were developed to investigate the plaque biomechanical conditions and investigate the impact of erosioninduced inflammation on biomechanical conditions.In vivo OCTand Biplane X-ray angiographic data of eroded coronary plaque were acquired from one male patient(age:64). OCT images were segmented manually with external elastic membrane contour and the trailing edge of the lipid-rich necrotic core(lipid)assumed to have positive remodeling ratio 1.1.Locations with luminal surface having direct contact with intraluminal thrombus on OCT images were identified erosion sites.Fusion of OCT and biplane X-ray angiographic data were performed to obtain the 3D coronary geometry.OCT-based FSI models with pre-shrink-stretch process and anisotropic material properties were constructed following previously established procedures.To reflect tissue weakening caused by erosion-induced inflammation,the material stiffness of plaque intima at the erosion site was adjust to one tenth of un-eroded fibrous plaque tissue.Three FSI models were constructed to investigate the impacts of inflammation and lipid component on plaque biomechanics:M1,without erosion(this means plaque intima at the erosion sites were not softened)and without inclusion of lipid component;M2,with erosion but no lipid;M3,with erosion and inclusion of lipid.FSI models were solved by ADINA to obtain the biomechanical conditions at peak blood pressure including plaque wall stress/strain(PWS/PWSn)and flow wall shear stress(WSS).The average values of three biomechanical conditions at the erosion sites and at the fibrous cap overlaying lipid component were calculated from three models for analysis.The results of M1 and M2 were compared to investigate the impact of erosion-induced inflammation on plaque biomechanics.Mean PWS value decreases from 49.98 kPa to 18.83 kPa(62.32%decrease)while Mean PWSn value increases from 0.123 1 to 0.138 4(12%increase)as the material stiffness becomes 10times soft.Comparing M2 and M3 at the cap sites,M3(with inclusion of lipid)will elevates mean PWS and PWSn values by48.59%and 16.09%,respectively.The impacts of erosion and lipid on flow shear stress were limited(<2%).To conclude,erosion-induced inflammation would lead to lower stress distribution but larger strain distribution,while lipid would elevate both stress and strain conditions.This shows the influence of erosion and lipid component has impacts on stress/strain cal-culations which are closely related to plaque assessment.展开更多
In this paper, we present a novel scheme for hierarchical joint remote state preparation（HJRSP） in a deterministic manner, where two senders can jointly and remotely prepare an arbitrary single-qubit at three receiv...In this paper, we present a novel scheme for hierarchical joint remote state preparation（HJRSP） in a deterministic manner, where two senders can jointly and remotely prepare an arbitrary single-qubit at three receivers＇ port. A six-particle partially entangled state is pre-shared as the quantum channel. There is a hierarchy among the receivers concerning their powers to reconstruct the target state. Due to various unitary operations and projective measurements, the unit success probability can always be achieved irrespective of the parameters of the pre-shared partially entangled state.展开更多
For lack of effective resource adjustment method, the supply-demand relationship of each resource in P2P content delivery system are often unbalanced. Especially after a popular content releasing, a burst of downloade...For lack of effective resource adjustment method, the supply-demand relationship of each resource in P2P content delivery system are often unbalanced. Especially after a popular content releasing, a burst of downloaders often can＇t find sufficient uploaders and their request may starve the upload capacity of server. Therefore the overall system QoS may be degraded. To tackle such issue, this paper proposes a download rate accelerate mechanism, called motivate mechanism. With it, the system can quickly find out the files becoming insufficient by monitoring the operating status of the files hourly, Then it promptly increase the number of copies of those files by using free rider nodes so that the whole system QoS is maintained and the system performance is improved. The experiment results on the practical operating system of Tencent demonstrated that the proposed mechanism increases the download rate, saves the traffic on the server and optimizes the system performance.展开更多
Internet service providers(ISPs)are paying more attention to the Quality of Experience(QoE)of the web service that is one of the most widely used Internet services.Measuring it with existing systems deployed in the ne...Internet service providers(ISPs)are paying more attention to the Quality of Experience(QoE)of the web service that is one of the most widely used Internet services.Measuring it with existing systems deployed in the network so far may save investment for ISPs since no additional QoE system is required.In this paper,with Domain Name System(DNS)resolution data that are available in the ISP’network,we propose the First Webpage Time(FWT)algorithm in order to measure the QoE of the web service.The proposed FWT algorithm is analyzed in theory,which shows that its precision is guaranteed.Experiments based on the ISP’s DNS resolution data are carried out to evaluate the proposed FWT algorithm.展开更多
As one of the most promising communication technologies for vehicular networks, LTE-V has the advantages of wide coverage and a high transmission rate. 3 GPP released the technical specification of LTE-V in March 2017...As one of the most promising communication technologies for vehicular networks, LTE-V has the advantages of wide coverage and a high transmission rate. 3 GPP released the technical specification of LTE-V in March 2017, launching a spate of related research and industrialization. In this paper, we propose a communication model based on Markov process to evaluate the reliability of LTE-V. We derived the Packet Delivery Rate(PDR) of LTE-V based on the model. Moreover, we use Poisson process to model the distribution of vehicles on a highway,then combine the communication model with the vehicles’ distribution to derive the PDR under this scenario. To verify the correctness of the proposed model, we established a simulation program on the MATLAB platform. By comparing the simulation results and the mathematical results, we found that simulation results are a very good fit for the model.展开更多
We analyzed and improved a collision avoidance strategy, which was supported by Long Term EvolutionVehicle(LTE-V)-based Vehicle-to-Vehicle(V2 V) communication, for automated vehicles. This work was completed in two st...We analyzed and improved a collision avoidance strategy, which was supported by Long Term EvolutionVehicle(LTE-V)-based Vehicle-to-Vehicle(V2 V) communication, for automated vehicles. This work was completed in two steps. In the first step, we analyzed the probability distribution of message transmission time, which was conditional on transmission distance and vehicle density. Our analysis revealed that transmission time exhibited a near-linear increase with distance and density. We also quantified the trade-off between high/low resource reselection probabilities to improve the setting of media access parameters. In the second step, we studied the required safety distance in accordance with the response time, i.e., the transmission time, derived on the basis of a novel concept of Responsibility-Sensitive Safety(RSS). We improved the strategy by considering the uncertainty of response time and its dependence on vehicle distance and density. We performed theoretical analysis and numerical testing to illustrate the effectiveness of the improved robust RSS strategy. Our results enhance the practicability of building driverless highways with special lanes reserved for the exclusive use of LTE-V vehicles.展开更多
An In P-based monolithically integrated few-mode transmitter aiming at the combination of wavelength division multiplexing（WDM） and mode division multiplexing（MDM） technologies is proposed. The core elements of th...An In P-based monolithically integrated few-mode transmitter aiming at the combination of wavelength division multiplexing（WDM） and mode division multiplexing（MDM） technologies is proposed. The core elements of the proposed transmitter are mode converters and a wavelength-mode division multiplexer that are all based on multimode interference（MMI） couplers. Simulations show that the wavelength-mode division multiplexer has a large fabrication tolerance of 30 and 0.5 μm for the length and the width of the device, respectively.A low loss below 0.26 dB for the passive parts of the transmitter is obtained in the whole C-band wavelength range.展开更多
To provide preferential protection for users while keeping good service utility, a preferential private recommendation framework(named as PrefER) is proposed. In this framework, a preferential budget allocation scheme...To provide preferential protection for users while keeping good service utility, a preferential private recommendation framework(named as PrefER) is proposed. In this framework, a preferential budget allocation scheme is designed and implemented at the system side to provide multilevel protection.And users’ preference is utilized at the user side to improve recommendation performance without increasing users’ burden. This framework is generic enough to be employed with other schemes. Recommendation accuracy based on the MovieLens dataset by the collaborative filtering schemes and PrefER are compared and analyzed.The experimental results show that PrefER can provide preferential privacy protection with the improvement of recommendation accuracy.展开更多
基金This work was supported by the National Key R&D Program of China No.2019YFB1802800.
文摘In 6G era,service forms in which computing power acts as the core will be ubiquitous in the network.At the same time,the collaboration among edge computing,cloud computing and network is needed to support edge computing service with strong demand for computing power,so as to realize the optimization of resource utilization.Based on this,the article discusses the research background,key techniques and main application scenarios of computing power network.Through the demonstration,it can be concluded that the technical solution of computing power network can effectively meet the multi-level deployment and flexible scheduling needs of the future 6G business for computing,storage and network,and adapt to the integration needs of computing power and network in various scenarios,such as user oriented,government enterprise oriented,computing power open and so on.
基金supported by the National Key Research and Development Plan under grant No. 2016YFB0502000
文摘Indoor positioning systems have been sufficiently researched to provide location information of persons and devices.This paper is focused on the current research and further development of indoor positioning.The standard evolution and industry development are summarized.There are various positioning systems according to the scenarios,cost and accuracy.However,there is a basic positioning system framework including information extraction,measurement and calculation.In particular,the detailed positioning technologies mainly including cellular positioning and Local Area Network(LAN) positioning are listed and compared to provide a reference for practical applications.Finally,we summarize the challenges of indoor positioning and give a3-phase evolution route.
基金supported in part by program for National Natural Science Foundation of China under Grant No.61271184863 Program of China under Grant No.2013AA013301+1 种基金New Century Excellent Talents in University(NCET-11-0594)Open Fund of the State Key Laboratory of Integrated Services Networks(No.ISN12-03)
文摘To solve the contradiction between the increasing demand of diverse vehicular wireless applications and the shortage of spectrum resource, a novel cognitive cooperative vehicular ad-hoc network （CC- VANET） framework is proposed in this paper. Firstly, we develop an adaptive cognitive spectrum sensing （ACSS） mechanism which can help to trigger and adjust the spectrum sensing window according to network traffic load status and communication quality. And then, Generalized Nash Bargaining SoLution （GNBS）, which can achieve a good tradeoff between efficiency and weighted fairness, is proposed to formulate the asymmetric inter- cell resource allocation. Finally, GNBS- Safety （GNBS-S） scheme is developed to enhance the Quality of Service （QoS） of safety applications, especially in the heavy load status, where the bandwidth demanded and supplied cannot be matched well. Furthermore, the primary user activity （PUA） which can cause rate loss to secondary users, is also considered to alleviate its influence to fairness. Simulation results indicate that the proposed CC-VANET scheme can greatly improve the spectrum efficiency and reduce the transmission delay and packet loss rate on the heavy contention status. And GNBS spectrum allocation scheme outperforms both the Max-rain and Max-rate schemes, and canenhance the communication reliability of safety service considerably in CC-VANET.
基金supported by the National High-Tech R&D Program (863 Program) No. 2015AA01A705the National Natural Science Foundation of China under Grant No. 61572072+1 种基金the National Science and Technology Major Project No. 2015ZX03001041Fundamental Research Funds for the Central Universities "Research on the System of Personalized Education using Big Data"
文摘Resource allocation is crucial for satellite networks. In this paper, we propose a multi-resource fair allocation scheme, namely Dominant and Max-min Fair(DMMF), to efficiently and fairly allocate resources. It consists of two allocation stages, dominant resource fair(DRF) allocation stage and max-min fairness(MMF) allocation stage. The proposed DMMF scheme exhibits desirable properties, including share incentive, strategy proofness, envy freeness and Pareto optimality. Meanwhile, DMMF can improve the allocation efficiency and reach 100% allocation efficiency.
基金supported by the National Nature Science Foundation of China(NSFC 60622110,61471220,91538107,91638205)National Basic Research Project of China(973,2013CB329006),GY22016058
文摘With the popularity of smart handheld devices, mobile streaming video has multiplied the global network traffic in recent years. A huge concern of users' quality of experience(Qo E) has made rate adaptation methods very attractive. In this paper, we propose a two-phase rate adaptation strategy to improve users' real-time video Qo E. First, to measure and assess video Qo E, we provide a continuous Qo E prediction engine modeled by RNN recurrent neural network. Different from traditional Qo E models which consider the Qo E-aware factors separately or incompletely, our RNN-Qo E model accounts for three descriptive factors(video quality, rebuffering, and rate change) and reflects the impact of cognitive memory and recency. Besides, the video playing is separated into the initial startup phase and the steady playback phase, and we takes different optimization goals for each phase: the former aims at shortening the startup delay while the latter ameliorates the video quality and the rebufferings. Simulation results have shown that RNN-Qo E can follow the subjective Qo E quite well, and the proposed strategy can effectively reduce the occurrence of rebufferings caused by the mismatch between the requested video rates and the fluctuated throughput and attains standout performance on real-time Qo E compared with classical rate adaption methods.
文摘A forest fire is a severe threat to forest resources and human life, In this paper, we propose a forest-fire detection system that has an artificial neural network algorithm implemented in a wireless sensor network （WSN）. The proposed detection system mitigates the threat of forest fires by provide accurate fire alarm with low maintenance cost. The accuracy is increased by the novel multi- criteria detection, referred to as an alarm decision depends on multiple attributes of a forest fire. The multi-criteria detection is implemented by the artificial neural network algorithm. Meanwhile, we have developed a prototype of the proposed system consisting of the solar batter module, the fire detection module and the user interface module.
文摘Understanding cardiac blood flow behaviors is of importance for cardiovascular research and clinical assessment of ventricle functions.Patient-specific Echo-based left ventricle(LV)fluid-structure interaction(FSI)models were introduced to perform ventricle mechanical analysis,investigate flow behaviors,and evaluate the impact of myocardial infarction(MI)and hypertension on blood flow in the LV.Echo image data were acquired from 3 patients with consent obtained:one healthy volunteer(P1),one hypertension patient(P2),and one patient who had an inferior and posterior myocardial infarction(P3).The nonlinear Mooney-Rivlin model was used for ventricle tissue with material parameter values chosen to match echo-measure LV volume data.Using the healthy case as baseline,LV with MI had lower peak flow velocity(30%lower at beginejection)and hypertension LV had higher peak flow velocity(16%higher at begin-filling).The vortex area(defined as the area with vorticity>0)for P3 was 19%smaller than that of P1.The vortex area for P2 was 12%smaller than that of P1.At peak of filling,the maximum flow shear stress(FSS)for P2 and P3 were 390%higher and 63%lower than that of P1,respectively.Meanwhile,LV stress and strain of P2 were 41%and 15%higher than those of P1,respectively.LV stress and strain of P3 were 36%and 42%lower than those of P1,respectively.In conclusion,FSI models could provide both flow and structural stress/strain information which would serve as the base for further cardiovascular investigations related to disease initiation,progression,and treatment strategy selections.Large-scale studies are needed to validate our findings.
基金supported in part by NSFC ( 11672001,11802060)Jiangsu NSF ( BK20180352)Jiangsu Province Science and Technology Agency ( BE2016785)
文摘Plaque erosion,together with plaque rupture,is a common cause for acute coronary syndrome(ACS).Plaque erosion alone is responsible for about one third of the patients with ACS.Eroded plaque is defined as thrombosed,endothelium-absent and non-ruptured but often-inflamed plaques based on histological findings.Even though there is efficient imaging technologies to detect the eroded plaque in vivo and tailored treatment strategy has also been developed for ACScaused by erosion in clinics,the pathogenesis mechanisms that cause plaque erosion are not fully understood.It is widely postulated that thrombus formation and endothelial apoptosis(the precursors of plaque erosion)have closed association with biomechanical conditions in the coronary vessel.Revealing of the mechanical conditions in the eroded plaque could advance our knowledge in understanding the formation of plaque erosion.To this end,patient-specific OCT-based fluid-structure interaction(FSI)models were developed to investigate the plaque biomechanical conditions and investigate the impact of erosioninduced inflammation on biomechanical conditions.In vivo OCTand Biplane X-ray angiographic data of eroded coronary plaque were acquired from one male patient(age:64). OCT images were segmented manually with external elastic membrane contour and the trailing edge of the lipid-rich necrotic core(lipid)assumed to have positive remodeling ratio 1.1.Locations with luminal surface having direct contact with intraluminal thrombus on OCT images were identified erosion sites.Fusion of OCT and biplane X-ray angiographic data were performed to obtain the 3D coronary geometry.OCT-based FSI models with pre-shrink-stretch process and anisotropic material properties were constructed following previously established procedures.To reflect tissue weakening caused by erosion-induced inflammation,the material stiffness of plaque intima at the erosion site was adjust to one tenth of un-eroded fibrous plaque tissue.Three FSI models were constructed to investigate the impacts of inflammation and lipid component on plaque biomechanics:M1,without erosion(this means plaque intima at the erosion sites were not softened)and without inclusion of lipid component;M2,with erosion but no lipid;M3,with erosion and inclusion of lipid.FSI models were solved by ADINA to obtain the biomechanical conditions at peak blood pressure including plaque wall stress/strain(PWS/PWSn)and flow wall shear stress(WSS).The average values of three biomechanical conditions at the erosion sites and at the fibrous cap overlaying lipid component were calculated from three models for analysis.The results of M1 and M2 were compared to investigate the impact of erosion-induced inflammation on plaque biomechanics.Mean PWS value decreases from 49.98 kPa to 18.83 kPa(62.32%decrease)while Mean PWSn value increases from 0.123 1 to 0.138 4(12%increase)as the material stiffness becomes 10times soft.Comparing M2 and M3 at the cap sites,M3(with inclusion of lipid)will elevates mean PWS and PWSn values by48.59%and 16.09%,respectively.The impacts of erosion and lipid on flow shear stress were limited(<2%).To conclude,erosion-induced inflammation would lead to lower stress distribution but larger strain distribution,while lipid would elevate both stress and strain conditions.This shows the influence of erosion and lipid component has impacts on stress/strain cal-culations which are closely related to plaque assessment.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61701285 and 61701284)the Scientific Research Foundation of Shandong University of Science and Technology for Recruited Talents,China(Grant No.2017RCJJ070)China Postdoctoral Science Foundation Funded Project(Grant No.2017M622233)
文摘In this paper, we present a novel scheme for hierarchical joint remote state preparation（HJRSP） in a deterministic manner, where two senders can jointly and remotely prepare an arbitrary single-qubit at three receivers＇ port. A six-particle partially entangled state is pre-shared as the quantum channel. There is a hierarchy among the receivers concerning their powers to reconstruct the target state. Due to various unitary operations and projective measurements, the unit success probability can always be achieved irrespective of the parameters of the pre-shared partially entangled state.
基金National Science Foundation Project of P.R.China，China Postdoctoral Science Foundation，the Fundamental Research Funds for the Central Universities
文摘For lack of effective resource adjustment method, the supply-demand relationship of each resource in P2P content delivery system are often unbalanced. Especially after a popular content releasing, a burst of downloaders often can＇t find sufficient uploaders and their request may starve the upload capacity of server. Therefore the overall system QoS may be degraded. To tackle such issue, this paper proposes a download rate accelerate mechanism, called motivate mechanism. With it, the system can quickly find out the files becoming insufficient by monitoring the operating status of the files hourly, Then it promptly increase the number of copies of those files by using free rider nodes so that the whole system QoS is maintained and the system performance is improved. The experiment results on the practical operating system of Tencent demonstrated that the proposed mechanism increases the download rate, saves the traffic on the server and optimizes the system performance.
文摘Internet service providers(ISPs)are paying more attention to the Quality of Experience(QoE)of the web service that is one of the most widely used Internet services.Measuring it with existing systems deployed in the network so far may save investment for ISPs since no additional QoE system is required.In this paper,with Domain Name System(DNS)resolution data that are available in the ISP’network,we propose the First Webpage Time(FWT)algorithm in order to measure the QoE of the web service.The proposed FWT algorithm is analyzed in theory,which shows that its precision is guaranteed.Experiments based on the ISP’s DNS resolution data are carried out to evaluate the proposed FWT algorithm.
基金supported in part by the National Key Research and Development Program of China (No. 2018YFB1600600)the National Natural Science Foundation of China (No. 61673233)
文摘As one of the most promising communication technologies for vehicular networks, LTE-V has the advantages of wide coverage and a high transmission rate. 3 GPP released the technical specification of LTE-V in March 2017, launching a spate of related research and industrialization. In this paper, we propose a communication model based on Markov process to evaluate the reliability of LTE-V. We derived the Packet Delivery Rate(PDR) of LTE-V based on the model. Moreover, we use Poisson process to model the distribution of vehicles on a highway,then combine the communication model with the vehicles’ distribution to derive the PDR under this scenario. To verify the correctness of the proposed model, we established a simulation program on the MATLAB platform. By comparing the simulation results and the mathematical results, we found that simulation results are a very good fit for the model.
基金supported in part by the National Natural Science Foundation of China (No. 61673233)Beijing Municipal Science and Technology Program (No. D171100004917001/2)the Key Technologies Research and Development Program of the Thirteenth Five-Year Plan of China (No. 2018YFB1600600)
文摘We analyzed and improved a collision avoidance strategy, which was supported by Long Term EvolutionVehicle(LTE-V)-based Vehicle-to-Vehicle(V2 V) communication, for automated vehicles. This work was completed in two steps. In the first step, we analyzed the probability distribution of message transmission time, which was conditional on transmission distance and vehicle density. Our analysis revealed that transmission time exhibited a near-linear increase with distance and density. We also quantified the trade-off between high/low resource reselection probabilities to improve the setting of media access parameters. In the second step, we studied the required safety distance in accordance with the response time, i.e., the transmission time, derived on the basis of a novel concept of Responsibility-Sensitive Safety(RSS). We improved the strategy by considering the uncertainty of response time and its dependence on vehicle distance and density. We performed theoretical analysis and numerical testing to illustrate the effectiveness of the improved robust RSS strategy. Our results enhance the practicability of building driverless highways with special lanes reserved for the exclusive use of LTE-V vehicles.
基金supported by the National 973 Program of China(No.2014CB340102)the National Nature Science Foundation of China(Nos.61320106013 and61271066)
文摘An In P-based monolithically integrated few-mode transmitter aiming at the combination of wavelength division multiplexing（WDM） and mode division multiplexing（MDM） technologies is proposed. The core elements of the proposed transmitter are mode converters and a wavelength-mode division multiplexer that are all based on multimode interference（MMI） couplers. Simulations show that the wavelength-mode division multiplexer has a large fabrication tolerance of 30 and 0.5 μm for the length and the width of the device, respectively.A low loss below 0.26 dB for the passive parts of the transmitter is obtained in the whole C-band wavelength range.
基金supported by the National Natural Science Foundation of China(61872031)。
文摘To provide preferential protection for users while keeping good service utility, a preferential private recommendation framework(named as PrefER) is proposed. In this framework, a preferential budget allocation scheme is designed and implemented at the system side to provide multilevel protection.And users’ preference is utilized at the user side to improve recommendation performance without increasing users’ burden. This framework is generic enough to be employed with other schemes. Recommendation accuracy based on the MovieLens dataset by the collaborative filtering schemes and PrefER are compared and analyzed.The experimental results show that PrefER can provide preferential privacy protection with the improvement of recommendation accuracy.
