A channel assignment algorithm with awareness of link traffic is proposed in multi-radio multi-channel wireless mesh networks. First, the physical interference model based on the signal-to-interference-plus-noise rati...A channel assignment algorithm with awareness of link traffic is proposed in multi-radio multi-channel wireless mesh networks. First, the physical interference model based on the signal-to-interference-plus-noise ratio and successful transmission condition is described. The model is more suitable for a wireless communication environment than other existing models. Secondly, a pure integer quadratic programming （PIQP） model is used to solve the channel assignment problem and improve the capacity of wireless mesh networks. Consequently, a traffic- aware static channel assignment algorithm（TASC） is designed. The algorithm adopts some network parameters, including the network connectivity, the limitation of the number of radios and the successful transmission conditions in wireless communications. The TASC algorithm can diminish network interference and increase the efficiency of channel assignment while keeping the connectivity of the network. Finally, the feasibility and effectivity of the channel assignment solution are illustrated by the simulation results. Compared witb similar algorithms, the proposed algorithm can increase the capacity of WMNs.展开更多
To solve the excessive huge scale problem of the traditional multi-bit digital artificial neural network（ANN） hardware implementation methods,a bit-stream ANN hardware implementation method based on sigma delta（Σ...To solve the excessive huge scale problem of the traditional multi-bit digital artificial neural network（ANN） hardware implementation methods,a bit-stream ANN hardware implementation method based on sigma delta（ΣΔ） modulation is presented.The bit-stream adder,multiplier,threshold function unit and fully digital ΣΔ modulator are implemented in a field programmable gate array（FPGA）,and these bit-stream arithmetical units are employed to build the bit-stream artificial neuron.The function of the bit-stream artificial neuron is verified through the realization of the logic function and a linear classifier.The bit-stream perceptron based on the bit-stream artificial neuron with the pre-processed structure is proved to have the ability of nonlinear classification.The FPGA resource utilization of the bit-stream artificial neuron shows that the bit-stream ANN hardware implementation method can significantly reduce the demand of the ANN hardware resources.展开更多
In recent years, several researchers have applied workflow technologies for service automation on ubiquitous compating environments. However, most context-aware workflows do not offer a method to compose several workf...In recent years, several researchers have applied workflow technologies for service automation on ubiquitous compating environments. However, most context-aware workflows do not offer a method to compose several workflows in order to get mare large-scale or complicated workflow. They only provide a simple workflow model, not a composite workflow model. In this paper, the autorhs propose a context-aware workflow model to support composite workflows by expanding the patterns of the existing context-aware wrY：flows, which support the basic woddlow patterns. The suggested workflow model of. fers composite workflow patterns for a context-aware workflow, which consists of various flow patterns, such as simple, split, parallel flows, and subflow. With the suggested model, the model can easily reuse few of existing workflows to make a new workflow. As a result, it can save the development efforts and time of context-aware workflows and increase the workflow reusability. Therefore, the suggested model is expected to make it easy to develop applications related to context-aware workflow services on ubiquitous computing environments.展开更多
Virtualization is a common technology for resource sharing in data center. To make efficient use of data center resources, the key challenge is to map customer demands （modeled as virtual data center, VDC） to the ph...Virtualization is a common technology for resource sharing in data center. To make efficient use of data center resources, the key challenge is to map customer demands （modeled as virtual data center, VDC） to the physical data center effectively. In this paper, we focus on this problem. Distinct with previous works, our study of VDC embedding problem is under the assumption that switch resource is the bottleneck of data center networks （DCNs）. To this end, we not only propose relative cost to evaluate embedding strategy, decouple embedding problem into VM placement with marginal resource assignment and virtual link mapping with decided source-destination based on the property of fat-tree, but also design the traffic aware embedding algorithm （TAE） and first fit virtual link mapping （FFLM） to map virtual data center requests to a physical data center. Simulation results show that TAE＋FFLM could increase acceptance rate and reduce network cost （about 49% in the case） at the same time. The traffie aware embedding algorithm reduces the load of core-link traffic and brings the optimization opportunity for data center network energy conservation.展开更多
Objective:Correctly understanding and evaluating the level of public risk perception toward public health emergencies not only helps experts and decision-makers understand the public’s preventative health behaviors t...Objective:Correctly understanding and evaluating the level of public risk perception toward public health emergencies not only helps experts and decision-makers understand the public’s preventative health behaviors to these emergencies but also enhances their risk information communication with the public.The aim of this study was to develop a risk perception scale for public health emergencies and test its validity and reliability during the coronavirus disease 2019(COVID-19)pandemic.Methods:Guided by the theoretical model of risk perception,an initial scale was generated through literature review,group meetings,resident interviews,and expert consultation.A pretest and item screening were then conducted to develop a formal risk perception scale for public health emergencies.Finally,the reliability and validity of the scale were validated through a questionnaire survey of 504 Chinese adults.Results:The final scale had 9 items.The content validity index of the scale was 0.968,and the content validity index of individual items ranged from 0.83 to 1.00.Three common factors,dread risk perception,severe risk perception,and unknown risk perception,were extracted for exploratory factor analysis,and together they explained 66.26%of the variance in the score.Confirmatory factor analysis showed that the model had a satisfactory fit,whereχ^(2)/df=1.384,the goodness-of-fit index(GFI)=0.989,root mean square error of approximation(RMSEA)=0.028,root mean square residual(RMR)=0.018,comparative fit index(CFI)=0.995,normed fit index(NFI)=0.982,and non-normed fit index(NNFI)=0.990.The correlations between dimensions ranged from 0.306 to 0.483(P<0.01).Cronbach’s a was 0.793 for the total scale and ranged between 0.687 and 0.801 for the individual dimensions.The split-half coefficient was 0.861 for the total scale and ranged from 0.727 to 0.856 for induvial dimensions.The test-retest coefficient was 0.846 for the total scale and ranged from 0.843 to 0.868 for induvial dimensions.Conclusion:The developed scale for the risk perception of public health emergencies showed acceptable levels of reliability and validity,suggesting that it is suitable for evaluating residents’risk perception of public health emergencies.展开更多
Participation, support and understanding of countries along the Belt and Road are requisites for promoting and implementing this major initiative. Indonesia, a major ASEAN economy, is crucial but Indonesia has a limit...Participation, support and understanding of countries along the Belt and Road are requisites for promoting and implementing this major initiative. Indonesia, a major ASEAN economy, is crucial but Indonesia has a limited perception of the B&R initiative. Although its government welcomes it and the ruling coalition cooperates positively, parts of the military and opposition are skeptical of China's intent. The B&R initiative is well-received among the Indonesian Chinese group, while Indonesian academic circles remain cautious and somewhat critical. From a Chinese viewpoint, easing negative or hostile emotions appropriately would be well-timed. China should settle the Natuna issue, adjust its publicity in Indonesia, use diplomacy, and promote Sino-Indonesia cultural exchange and communications. Chinese enterprises should focus on project quality and uphold social responsibilities. Short-term goals are reducing Indonesia's opposition and obstruction of B&R, while long-term goals are enhancing the recognition and likeability of the Initiative's worthwhile plans.展开更多
In wireless multimedia communications, it is extremely difficult to derive general end-to-end capacity results because of decentralized packet scheduling and the interference between communicating nodes. In this paper...In wireless multimedia communications, it is extremely difficult to derive general end-to-end capacity results because of decentralized packet scheduling and the interference between communicating nodes. In this paper, we present a state-based channel capacity perception scheme to provide statistical Quality-of-Service (QoS) guarantees under a medium or high traffic load for IEEE 802.11 wireless multi-hop networks. The proposed scheme first perceives the state of the wireless link from the MAC retransmission information and extends this information to calculate the wireless channel capacity, particularly under a saturated traffic load, on the basis of the interference among flows and the link state in the wireless multi-hop networks. Finally, the adaptive optimal control algorithm allocates a network resource and forwards the data packet by taking into consideration the channel capacity deployments in multi-terminal or multi-hop mesh networks. Extensive computer simulations demonstrate that the proposed scheme can achieve better performance in terms of packet delivery ratio and network throughput compared to the existing capacity prediction schemes.展开更多
基金The National Basic Research Program of China(973Program)(No.2009CB320501)the Natural Science Foundation of Jiangsu Province(No.BK2010414)+1 种基金China Postdoctoral Science Foundation(No.20100480071)Specialized Research Fund for the Doctoral Program of Higher Education(No.20090092120029)
文摘A channel assignment algorithm with awareness of link traffic is proposed in multi-radio multi-channel wireless mesh networks. First, the physical interference model based on the signal-to-interference-plus-noise ratio and successful transmission condition is described. The model is more suitable for a wireless communication environment than other existing models. Secondly, a pure integer quadratic programming （PIQP） model is used to solve the channel assignment problem and improve the capacity of wireless mesh networks. Consequently, a traffic- aware static channel assignment algorithm（TASC） is designed. The algorithm adopts some network parameters, including the network connectivity, the limitation of the number of radios and the successful transmission conditions in wireless communications. The TASC algorithm can diminish network interference and increase the efficiency of channel assignment while keeping the connectivity of the network. Finally, the feasibility and effectivity of the channel assignment solution are illustrated by the simulation results. Compared witb similar algorithms, the proposed algorithm can increase the capacity of WMNs.
基金The National Natural Science Foundation of China (No.60576028)the Natural Science Foundation of Higher Education Institutions of Jiangsu Province(No.11KJB510004)
文摘To solve the excessive huge scale problem of the traditional multi-bit digital artificial neural network（ANN） hardware implementation methods,a bit-stream ANN hardware implementation method based on sigma delta（ΣΔ） modulation is presented.The bit-stream adder,multiplier,threshold function unit and fully digital ΣΔ modulator are implemented in a field programmable gate array（FPGA）,and these bit-stream arithmetical units are employed to build the bit-stream artificial neuron.The function of the bit-stream artificial neuron is verified through the realization of the logic function and a linear classifier.The bit-stream perceptron based on the bit-stream artificial neuron with the pre-processed structure is proved to have the ability of nonlinear classification.The FPGA resource utilization of the bit-stream artificial neuron shows that the bit-stream ANN hardware implementation method can significantly reduce the demand of the ANN hardware resources.
基金supported by the The Ministry of Knowledge Economy,Korea,the ITRC(Information Technology Research Center)support program(ⅡTA-2009-(C1090-0902-0007))
文摘In recent years, several researchers have applied workflow technologies for service automation on ubiquitous compating environments. However, most context-aware workflows do not offer a method to compose several workflows in order to get mare large-scale or complicated workflow. They only provide a simple workflow model, not a composite workflow model. In this paper, the autorhs propose a context-aware workflow model to support composite workflows by expanding the patterns of the existing context-aware wrY：flows, which support the basic woddlow patterns. The suggested workflow model of. fers composite workflow patterns for a context-aware workflow, which consists of various flow patterns, such as simple, split, parallel flows, and subflow. With the suggested model, the model can easily reuse few of existing workflows to make a new workflow. As a result, it can save the development efforts and time of context-aware workflows and increase the workflow reusability. Therefore, the suggested model is expected to make it easy to develop applications related to context-aware workflow services on ubiquitous computing environments.
基金This research was partially supported by the National Grand Fundamental Research 973 Program of China under Grant （No. 2013CB329103）, Natural Science Foundation of China grant （No. 61271171）, the Fundamental Research Funds for the Central Universities （ZYGX2013J002, ZYGX2012J004, ZYGX2010J002, ZYGX2010J009）, Guangdong Science and Technology Project （2012B090500003, 2012B091000163, 2012556031）.
文摘Virtualization is a common technology for resource sharing in data center. To make efficient use of data center resources, the key challenge is to map customer demands （modeled as virtual data center, VDC） to the physical data center effectively. In this paper, we focus on this problem. Distinct with previous works, our study of VDC embedding problem is under the assumption that switch resource is the bottleneck of data center networks （DCNs）. To this end, we not only propose relative cost to evaluate embedding strategy, decouple embedding problem into VM placement with marginal resource assignment and virtual link mapping with decided source-destination based on the property of fat-tree, but also design the traffic aware embedding algorithm （TAE） and first fit virtual link mapping （FFLM） to map virtual data center requests to a physical data center. Simulation results show that TAE＋FFLM could increase acceptance rate and reduce network cost （about 49% in the case） at the same time. The traffie aware embedding algorithm reduces the load of core-link traffic and brings the optimization opportunity for data center network energy conservation.
文摘Objective:Correctly understanding and evaluating the level of public risk perception toward public health emergencies not only helps experts and decision-makers understand the public’s preventative health behaviors to these emergencies but also enhances their risk information communication with the public.The aim of this study was to develop a risk perception scale for public health emergencies and test its validity and reliability during the coronavirus disease 2019(COVID-19)pandemic.Methods:Guided by the theoretical model of risk perception,an initial scale was generated through literature review,group meetings,resident interviews,and expert consultation.A pretest and item screening were then conducted to develop a formal risk perception scale for public health emergencies.Finally,the reliability and validity of the scale were validated through a questionnaire survey of 504 Chinese adults.Results:The final scale had 9 items.The content validity index of the scale was 0.968,and the content validity index of individual items ranged from 0.83 to 1.00.Three common factors,dread risk perception,severe risk perception,and unknown risk perception,were extracted for exploratory factor analysis,and together they explained 66.26%of the variance in the score.Confirmatory factor analysis showed that the model had a satisfactory fit,whereχ^(2)/df=1.384,the goodness-of-fit index(GFI)=0.989,root mean square error of approximation(RMSEA)=0.028,root mean square residual(RMR)=0.018,comparative fit index(CFI)=0.995,normed fit index(NFI)=0.982,and non-normed fit index(NNFI)=0.990.The correlations between dimensions ranged from 0.306 to 0.483(P<0.01).Cronbach’s a was 0.793 for the total scale and ranged between 0.687 and 0.801 for the individual dimensions.The split-half coefficient was 0.861 for the total scale and ranged from 0.727 to 0.856 for induvial dimensions.The test-retest coefficient was 0.846 for the total scale and ranged from 0.843 to 0.868 for induvial dimensions.Conclusion:The developed scale for the risk perception of public health emergencies showed acceptable levels of reliability and validity,suggesting that it is suitable for evaluating residents’risk perception of public health emergencies.
文摘Participation, support and understanding of countries along the Belt and Road are requisites for promoting and implementing this major initiative. Indonesia, a major ASEAN economy, is crucial but Indonesia has a limited perception of the B&R initiative. Although its government welcomes it and the ruling coalition cooperates positively, parts of the military and opposition are skeptical of China's intent. The B&R initiative is well-received among the Indonesian Chinese group, while Indonesian academic circles remain cautious and somewhat critical. From a Chinese viewpoint, easing negative or hostile emotions appropriately would be well-timed. China should settle the Natuna issue, adjust its publicity in Indonesia, use diplomacy, and promote Sino-Indonesia cultural exchange and communications. Chinese enterprises should focus on project quality and uphold social responsibilities. Short-term goals are reducing Indonesia's opposition and obstruction of B&R, while long-term goals are enhancing the recognition and likeability of the Initiative's worthwhile plans.
基金supported by the National Natural Science Foundation of China under Grants No.60972038,No.61001077,No.61101105 the Scientific Research Foundation for Nanjing University of Posts and Telecommunications under Grant No.NY211007+2 种基金 the Open Research Fund of National Mobile Communications Research Laboratory,Southeast University under Grant No.2011D05 Specialized Research Fund for the Doctoral Program of Higher Education under Grant No.20113223120002 University Natural Science Research Project of Jiangsu Province under Grant No.11KJB510016
文摘In wireless multimedia communications, it is extremely difficult to derive general end-to-end capacity results because of decentralized packet scheduling and the interference between communicating nodes. In this paper, we present a state-based channel capacity perception scheme to provide statistical Quality-of-Service (QoS) guarantees under a medium or high traffic load for IEEE 802.11 wireless multi-hop networks. The proposed scheme first perceives the state of the wireless link from the MAC retransmission information and extends this information to calculate the wireless channel capacity, particularly under a saturated traffic load, on the basis of the interference among flows and the link state in the wireless multi-hop networks. Finally, the adaptive optimal control algorithm allocates a network resource and forwards the data packet by taking into consideration the channel capacity deployments in multi-terminal or multi-hop mesh networks. Extensive computer simulations demonstrate that the proposed scheme can achieve better performance in terms of packet delivery ratio and network throughput compared to the existing capacity prediction schemes.
