Sensors based on personalized healthcare systems have been widely used in the medical field.However,energy limitations have greatly hindered the further development of medical sensors.For the traditional Medium Access...Sensors based on personalized healthcare systems have been widely used in the medical field.However,energy limitations have greatly hindered the further development of medical sensors.For the traditional Medium Access Control(MAC)protocol,the duration of low-power listening is fixed because it ignores that the available energy of sensors is different in some situations,which leads to a high delay and low energy utilization.In this paper,a Maximum Listening Length MAC(MLL-MAC)protocol is proposed to fully utilize the energy in the sensor-based systems.The MLL-MAC protocol is an improvement of the Receiver-Initiated(RI)MAC protocol.The main advance is that the sensor node performs the following additional operations:(1)The sender sends a beacon when it wakes up and sends data,thus establishing a communication link with the receiver in the listening state;(2)The receiver keeps listening as long as possible to reduce the delay when it wakes up and listens to the channel,which is different from the previous strategy in which the node turns into a sleep state immediately without receiving data.Furthermore,the sensor node can dynamically determine whether to send beacons and prolong listening duration according to its available energy level.The MLL-MAC protocol is evaluated through theoretical analysis and experimental results.The results show that,compared with the RI-MAC protocol,the MLL-MAC protocol can reduce the average end-to-end delay by 41.4%and improve the energy utilization by 15.1%.展开更多
In network theory,a complex network represents a system whose evolving structure and dynamic behavior contribute to its robustness.The natural connectivity is recently proposed as a spectral measure to characterize th...In network theory,a complex network represents a system whose evolving structure and dynamic behavior contribute to its robustness.The natural connectivity is recently proposed as a spectral measure to characterize the robustness of complex networks.We decompose the natural connectivity of a network as local natural connectivity of its connected components and quantify their contributions to the network robustness.In addition,we compare the natural connectivity of a network with that of an induced subgraph of it based on interlacing theorems.As an application,we derive an inequality for eigenvalues of Erdös-Rényi random graphs.展开更多
A photonic sensor with radio frequency(RF)power detection for body pressure monitoring is proposed.The sensor based on two fiber Bragg gratings(FBGs)can transfer the wavelength shift to the change of RF power.The pres...A photonic sensor with radio frequency(RF)power detection for body pressure monitoring is proposed.The sensor based on two fiber Bragg gratings(FBGs)can transfer the wavelength shift to the change of RF power.The pressure can be measured by modulating and processing one single frequency RF signal.The theoretical analysis and experimental results of the photonic sensor are presented and discussed.The pressure sensitivities are acquired with 2.62×10^(−5)mW/kPa at 2.14 GHz,2.46×10^(−5)mW/kPa at 2.21 GHz,2.81×10^(−5)mW/kPa at 2.37 GHz,and 3.02×10^(−5)mW/kPa at 2.45 GHz,respectively.Furthermore,the pressure measurements of pressed body parts are also obtained by the sensor.展开更多
Behavioral responses triggered by the perceived risk of experiencing the disease represent a key ingredient in the spread of epidemics across human population.In this paper,two forms of individual awareness(i.e.,the r...Behavioral responses triggered by the perceived risk of experiencing the disease represent a key ingredient in the spread of epidemics across human population.In this paper,two forms of individual awareness(i.e.,the risk perception of an emerging epidemic) are addressed:Contact awareness that increases with individual contact number,and local awareness that increases with the fraction of infected contacts.By extending the probability generating functionology,the author shows that it is possible to track the evolution of the degree distributions among susceptible and infected individuals when the underlying network of contacts is represented by a semi-random configuration model.It is hopefully to shed some light on the dynamic aspects of networked epidemiological models.展开更多
Correlations of active and passive random intersection graphs are studied in this paper. We present the joint probability generating function for degrees of GactVe（n, re, p） and GPaSSiW（n, re, p）, which are genera...Correlations of active and passive random intersection graphs are studied in this paper. We present the joint probability generating function for degrees of GactVe（n, re, p） and GPaSSiW（n, re, p）, which are generated by a random bipartite graph G＊ （n, ~rt, p） on n ＋ rn vertices.展开更多
Let N be a prime near-ring. We show two main results on the commutativity of N： （1） If there exist k, l ∈ N such that N admits a generalized derivation D satisfying either D（[x,y]） = xk[x,y]xl for all x,y ∈ N o...Let N be a prime near-ring. We show two main results on the commutativity of N： （1） If there exist k, l ∈ N such that N admits a generalized derivation D satisfying either D（[x,y]） = xk[x,y]xl for all x,y ∈ N or D（[x,y]） = -xk[x,y]xI for all x,y ∈ N, then N is a commutative ring. （2） If there exist k, l ∈ N such that N admits a generalized derivation D satisfying either D（x o y） = xk（x o y）xl for all x, y ∈ N or D（x o y） = -xk（x o y）xl for all x, y ∈ N, then N is a commutative ring. Moreover, some interesting relations between the prime graph and zero-divisor graph of N are studied.展开更多
Human behavioral responses fundamentally influence the spread of infectious disease. In this paper, we study a discrete-time SIS epidemic process in random networks. Three forms of individual awareness, namely, local ...Human behavioral responses fundamentally influence the spread of infectious disease. In this paper, we study a discrete-time SIS epidemic process in random networks. Three forms of individual awareness, namely, local awareness, global awareness and contact awareness, are considered. The effect of awareness is to reduce the risk of infection. [3ased on the stability theory of matrix difference equation, we derive analytically the epidemic threshold. It is found that both local and contact awareness can raise the epidemic threshold, while the global awareness only decreases the epidemic prevalence. Our results are in line with a recent result using differential equation-based methods.展开更多
In this paper,we study a long-range percolation model on the lattice Z d with multi-type vertices and directed edges.Each vertex x ∈ Z d is independently assigned a non-negative weight Wx and a type ψx,where(Wx) x∈...In this paper,we study a long-range percolation model on the lattice Z d with multi-type vertices and directed edges.Each vertex x ∈ Z d is independently assigned a non-negative weight Wx and a type ψx,where(Wx) x∈Z d are i.i.d.random variables,and(ψx) x∈Z d are also i.i.d.Conditionally on weights and types,and given λ,α > 0,the edges are independent and the probability that there is a directed edge from x to y is given by pxy = 1 exp(λφψ x ψ y WxWy /| x-y | α),where φij 's are entries from a type matrix Φ.We show that,when the tail of the distribution of Wx is regularly varying with exponent τ-1,the tails of the out/in-degree distributions are both regularly varying with exponent γ = α(τ-1) /d.We formulate conditions under which there exist critical values λ WCC c ∈(0,∞) and λ SCC c ∈(0,∞) such that an infinite weak component and an infinite strong component emerge,respectively,when λ exceeds them.A phase transition is established for the shortest path lengths of directed and undirected edges in the infinite component at the point γ = 2,where the out/in-degrees switch from having finite to infinite variances.The random graph model studied here features some structures of multi-type vertices and directed edges which appear naturally in many real-world networks,such as the SNS networks and computer communication networks.展开更多
基金This work is supported in part by the National Natural Science Foundation of China(No.62072475,No.61772554).
文摘Sensors based on personalized healthcare systems have been widely used in the medical field.However,energy limitations have greatly hindered the further development of medical sensors.For the traditional Medium Access Control(MAC)protocol,the duration of low-power listening is fixed because it ignores that the available energy of sensors is different in some situations,which leads to a high delay and low energy utilization.In this paper,a Maximum Listening Length MAC(MLL-MAC)protocol is proposed to fully utilize the energy in the sensor-based systems.The MLL-MAC protocol is an improvement of the Receiver-Initiated(RI)MAC protocol.The main advance is that the sensor node performs the following additional operations:(1)The sender sends a beacon when it wakes up and sends data,thus establishing a communication link with the receiver in the listening state;(2)The receiver keeps listening as long as possible to reduce the delay when it wakes up and listens to the channel,which is different from the previous strategy in which the node turns into a sleep state immediately without receiving data.Furthermore,the sensor node can dynamically determine whether to send beacons and prolong listening duration according to its available energy level.The MLL-MAC protocol is evaluated through theoretical analysis and experimental results.The results show that,compared with the RI-MAC protocol,the MLL-MAC protocol can reduce the average end-to-end delay by 41.4%and improve the energy utilization by 15.1%.
文摘In network theory,a complex network represents a system whose evolving structure and dynamic behavior contribute to its robustness.The natural connectivity is recently proposed as a spectral measure to characterize the robustness of complex networks.We decompose the natural connectivity of a network as local natural connectivity of its connected components and quantify their contributions to the network robustness.In addition,we compare the natural connectivity of a network with that of an induced subgraph of it based on interlacing theorems.As an application,we derive an inequality for eigenvalues of Erdös-Rényi random graphs.
基金supported by the Key R&D Project of Science and Technology Department of Sichuan Province(No.2023YFS0122)the Health Research Project for Cadres of Sichuan Province(No.2022-204).
文摘A photonic sensor with radio frequency(RF)power detection for body pressure monitoring is proposed.The sensor based on two fiber Bragg gratings(FBGs)can transfer the wavelength shift to the change of RF power.The pressure can be measured by modulating and processing one single frequency RF signal.The theoretical analysis and experimental results of the photonic sensor are presented and discussed.The pressure sensitivities are acquired with 2.62×10^(−5)mW/kPa at 2.14 GHz,2.46×10^(−5)mW/kPa at 2.21 GHz,2.81×10^(−5)mW/kPa at 2.37 GHz,and 3.02×10^(−5)mW/kPa at 2.45 GHz,respectively.Furthermore,the pressure measurements of pressed body parts are also obtained by the sensor.
基金supported by Air Force Office of Scientific Research under Grant No.FA9550-09-1-0165
文摘Behavioral responses triggered by the perceived risk of experiencing the disease represent a key ingredient in the spread of epidemics across human population.In this paper,two forms of individual awareness(i.e.,the risk perception of an emerging epidemic) are addressed:Contact awareness that increases with individual contact number,and local awareness that increases with the fraction of infected contacts.By extending the probability generating functionology,the author shows that it is possible to track the evolution of the degree distributions among susceptible and infected individuals when the underlying network of contacts is represented by a semi-random configuration model.It is hopefully to shed some light on the dynamic aspects of networked epidemiological models.
文摘Correlations of active and passive random intersection graphs are studied in this paper. We present the joint probability generating function for degrees of GactVe（n, re, p） and GPaSSiW（n, re, p）, which are generated by a random bipartite graph G＊ （n, ~rt, p） on n ＋ rn vertices.
文摘Let N be a prime near-ring. We show two main results on the commutativity of N： （1） If there exist k, l ∈ N such that N admits a generalized derivation D satisfying either D（[x,y]） = xk[x,y]xl for all x,y ∈ N or D（[x,y]） = -xk[x,y]xI for all x,y ∈ N, then N is a commutative ring. （2） If there exist k, l ∈ N such that N admits a generalized derivation D satisfying either D（x o y） = xk（x o y）xl for all x, y ∈ N or D（x o y） = -xk（x o y）xl for all x, y ∈ N, then N is a commutative ring. Moreover, some interesting relations between the prime graph and zero-divisor graph of N are studied.
文摘Human behavioral responses fundamentally influence the spread of infectious disease. In this paper, we study a discrete-time SIS epidemic process in random networks. Three forms of individual awareness, namely, local awareness, global awareness and contact awareness, are considered. The effect of awareness is to reduce the risk of infection. [3ased on the stability theory of matrix difference equation, we derive analytically the epidemic threshold. It is found that both local and contact awareness can raise the epidemic threshold, while the global awareness only decreases the epidemic prevalence. Our results are in line with a recent result using differential equation-based methods.
文摘In this paper,we study a long-range percolation model on the lattice Z d with multi-type vertices and directed edges.Each vertex x ∈ Z d is independently assigned a non-negative weight Wx and a type ψx,where(Wx) x∈Z d are i.i.d.random variables,and(ψx) x∈Z d are also i.i.d.Conditionally on weights and types,and given λ,α > 0,the edges are independent and the probability that there is a directed edge from x to y is given by pxy = 1 exp(λφψ x ψ y WxWy /| x-y | α),where φij 's are entries from a type matrix Φ.We show that,when the tail of the distribution of Wx is regularly varying with exponent τ-1,the tails of the out/in-degree distributions are both regularly varying with exponent γ = α(τ-1) /d.We formulate conditions under which there exist critical values λ WCC c ∈(0,∞) and λ SCC c ∈(0,∞) such that an infinite weak component and an infinite strong component emerge,respectively,when λ exceeds them.A phase transition is established for the shortest path lengths of directed and undirected edges in the infinite component at the point γ = 2,where the out/in-degrees switch from having finite to infinite variances.The random graph model studied here features some structures of multi-type vertices and directed edges which appear naturally in many real-world networks,such as the SNS networks and computer communication networks.
