Several conclusions on minimal cutset are proposed, from which a new algorithm is deduced to evaluate the unreliability of flow networks. Beginning with one unreliability product of the network, disjointed unreliabili...Several conclusions on minimal cutset are proposed, from which a new algorithm is deduced to evaluate the unreliability of flow networks. Beginning with one unreliability product of the network, disjointed unreliability products are branched out one by one, every of which is selected from the network minimal cutsets. Finally the unreliability of the network is obtained by adding all these unreliability products up.展开更多
The work deals with the development of analytical model of multichannel technical queuing system with unreliable servers and input memory where server failure flows and incoming request flows comply with Poissonian la...The work deals with the development of analytical model of multichannel technical queuing system with unreliable servers and input memory where server failure flows and incoming request flows comply with Poissonian laws, while the flows of failed facilities repairs and flows of incoming requests comply with exponential laws of probability distribution. Random process of system change-over is a Markovian process with continuous time and discrete states. Relations binding basic parameters and output characteristics of the system indicated are obtained as probabilities of system staying in the given moment in one of the possible states. The proposed model is the most generalized compared to some models known in literature which could be considered as special cases of the considered model.展开更多
The work is dedicated to the development of analytical model of probability estimation of reliability, productivity, quality and efficiency of functioning of the complex technical queuing system consisting of the arbi...The work is dedicated to the development of analytical model of probability estimation of reliability, productivity, quality and efficiency of functioning of the complex technical queuing system consisting of the arbitrary number of marked groups of the service devises (channels, facilities, servers) differing with reliable characteristics (parameters of refusals and restorations) of forming their composition (also of arbitrary number) marked, identical, unreliable and restorable serving channels in which for serving come in requirements with intensities depending on marking of channels. In the considered system it is supposed that the currents of refusals of serving devices and currents of coming requirements are subdued to Poisson, and the currents of restorations of refused devices and the currents of services of coming requirements—exponential laws of distribution of probabilities. A stochastic process of transfers of a system by that is Markovian process with continuous time and discrete states. Correlations linking the basic parameters and exit characteristics of the systems of the pointed out type are obtained in a view of probabilities of the system location in the given moment of time in one of the possible states.展开更多
This paper concerns ultimately bounded output-feedback control problems for networked systems with unknown nonlinear dynamics. Sensor-to-observer signal transmission is facilitated over networks that has communication...This paper concerns ultimately bounded output-feedback control problems for networked systems with unknown nonlinear dynamics. Sensor-to-observer signal transmission is facilitated over networks that has communication constraints.These transmissions are carried out over an unreliable communication channel. In order to enhance the utilization rate of measurement data, a buffer-aided strategy is novelly employed to store historical measurements when communication networks are inaccessible. Using the neural network technique, a novel observer-based controller is introduced to address effects of signal transmission behaviors and unknown nonlinear dynamics.Through the application of stochastic analysis and Lyapunov stability, a joint framework is constructed for analyzing resultant system performance under the introduced controller. Subsequently, existence conditions for the desired output-feedback controller are delineated. The required parameters for the observerbased controller are then determined by resolving some specific matrix inequalities. Finally, a simulation example is showcased to confirm method efficacy.展开更多
Based on the narrative theory of Shlomith Rimmon-Kenan,the present paper will analyze the close connection between the choice and order of the focalizers and the themes of the novel to show that they are chosen and ar...Based on the narrative theory of Shlomith Rimmon-Kenan,the present paper will analyze the close connection between the choice and order of the focalizers and the themes of the novel to show that they are chosen and arranged deliberately and accorded to its themes.展开更多
For conventional power systems,the forced outage of components is the major cause of load shedding.Unreliability tracing is utilized to allocate the total system load-shedding risk among individual components in ac-co...For conventional power systems,the forced outage of components is the major cause of load shedding.Unreliability tracing is utilized to allocate the total system load-shedding risk among individual components in ac-cordance with their different contributions.Therefore,critical components are identified and pertinent measures can be taken to improve system reliability.The integra-tion of wind power introduces additional risk factors into power systems,causing previous unreliability tracing methods to become inapplicable.In this paper,a novel unreliability tracing method is proposed that considers both aleatory and epistemic uncertainties in wind power output and their impacts on power system load-shedding risk.First,modelling methods for wind power output considering aleatory and epistemic uncertainties and component outages are proposed.Then,a variance-based index is proposed to measure the contributions of indi-vidual risk factors to the system load-shedding risk.Fi-nally,a novel unreliability tracing framework is devel-oped to identify the critical factors that affect power sys-tem reliability.Case studies verify the ability of the pro-posed method to accurately allocate load-shedding risk to individual risk factors,thus providing decision support for reliability enhancement.展开更多
Since its publication, Wuthering Heights has won great popularity home and abroad for the complexity and delicacy of the narration. However, the story is not true as the unreliability of its narrator is obvious as far...Since its publication, Wuthering Heights has won great popularity home and abroad for the complexity and delicacy of the narration. However, the story is not true as the unreliability of its narrator is obvious as far as it is judged by Rimmon-Kenan's theory of narrative unreliability.展开更多
Different from traditional aggregation method, the unreliable buffers are originally considered and a more general aggregation method is offered, in which not only the unreliable buffers are considered, but also the p...Different from traditional aggregation method, the unreliable buffers are originally considered and a more general aggregation method is offered, in which not only the unreliable buffers are considered, but also the probabilities of system states are obtained by a discrete model rather than the continuous flow model of unreliable manufacturing systems. The solution technique is offered to get the system sate probabilities. The method advances the traditional system aggregation techniques. Numerical results specify the extended aggregation method and also show that the unreliable limited buffers have a strong impact on the efficiency of the production lines.展开更多
Alice Munro,a famous Canadian Canadian short-story writer.She gained the Nobel Prize for Literature in 2013.Munro’s works focus on women and adolescents.She also writes about the illness and love of the elderly.“The...Alice Munro,a famous Canadian Canadian short-story writer.She gained the Nobel Prize for Literature in 2013.Munro’s works focus on women and adolescents.She also writes about the illness and love of the elderly.“The Bear Came over the Mountain”is one of them.In this story,Munro adopts unreliable narration to depict love between Grant and Fiona.This paper aims to study the love writing and its unreliable narration in this story.Based on the text of love writing,this paper analyzes the specific strategies of unreliable narration.The author believes that the unreliable narration of the love text in the story can be divided into the unreliable narration of character type and information type.Through analysis of these two types of narration in the story,special meaning of unreliable narration to describe love can be found.Besides,Munro’s description also contains her own insight of love:the course of true love does not always run smooth.展开更多
Based on rhetorical research methods of the unreliability,the paper intends to explore the unreliable narrative strategies of the narrator in Grace Paley's The Loudest Voice from the perspectives of the Wayne Boot...Based on rhetorical research methods of the unreliability,the paper intends to explore the unreliable narrative strategies of the narrator in Grace Paley's The Loudest Voice from the perspectives of the Wayne Booth's criterion of the distance between the narrator and the implied author and James Phelan's extension of unreliability on the basis of classical rhetorical narratology,point⁃ing out that the unreliability serves as the narrative trap which is set up to reveal the inner theme of the work:"The loudest voice"-what the protagonist thought she certainly possessed was only her illusion instead of the truth,and Eastern European Jewish com⁃munity was de facto marginalized by the mainstream culture at that time.展开更多
The Tell-Tale Heart is a short story by Edgar Allan Poe. The story is first-person narrative of a narrator who murdered an old man with a clouded eye. This paper aims at identifying the speaker"I"as an unrel...The Tell-Tale Heart is a short story by Edgar Allan Poe. The story is first-person narrative of a narrator who murdered an old man with a clouded eye. This paper aims at identifying the speaker"I"as an unreliable narrator through analyzing the motivation, process and confession of the crime. It is found out that the narrator symbolizes man of evil, while, the old man's vulture eye symbolizes virtue. It's a story about the conflict between evil and virtue.展开更多
As an encyclopedic novel and the summit of Chinese classical literary creation,Hongloumeng has not received due critical attention to its unusual narrative style,let alone abundant unreliable narrative.From unreliable...As an encyclopedic novel and the summit of Chinese classical literary creation,Hongloumeng has not received due critical attention to its unusual narrative style,let alone abundant unreliable narrative.From unreliable narration of narrator and character,this research probes into effective translation strategies to achieve a balance between source text and target text,in light of a comparative analysis of typical illustrations taken from A Dream of Red Mansions and The Story of the Stone.展开更多
Cyber-physical systems(CPSs)have emerged as an essential area of research in the last decade,providing a new paradigm for the integration of computational and physical units in modern control systems.Remote state esti...Cyber-physical systems(CPSs)have emerged as an essential area of research in the last decade,providing a new paradigm for the integration of computational and physical units in modern control systems.Remote state estimation(RSE)is an indispensable functional module of CPSs.Recently,it has been demonstrated that malicious agents can manipulate data packets transmitted through unreliable channels of RSE,leading to severe estimation performance degradation.This paper aims to present an overview of recent advances in cyber-attacks and defensive countermeasures,with a specific focus on integrity attacks against RSE.Firstly,two representative frameworks for the synthesis of optimal deception attacks with various performance metrics and stealthiness constraints are discussed,which provide a deeper insight into the vulnerabilities of RSE.Secondly,a detailed review of typical attack detection and resilient estimation algorithms is included,illustrating the latest defensive measures safeguarding RSE from adversaries.Thirdly,some prevalent attacks impairing the confidentiality and data availability of RSE are examined from both attackers'and defenders'perspectives.Finally,several challenges and open problems are presented to inspire further exploration and future research in this field.展开更多
Fault tree analysis is an effective method for predicting the reliability of a system. It gives a pictorial representation and logical framework for analyzing the reliability. Also, it has been used for a long time as...Fault tree analysis is an effective method for predicting the reliability of a system. It gives a pictorial representation and logical framework for analyzing the reliability. Also, it has been used for a long time as an effective method for the quantitative and qualitative analysis of the failure modes of critical systems. In this paper, we propose a new general coverage model (GCM) based on hardware independent faults. Using this model, an effective software tool can be constructed to detect, locate and recover fault from the faulty system. This model can be applied to identify the key component that can cause the failure of the system using failure mode effect analysis (FMEA).展开更多
This paper considers the discrete-time GeoX/G/1 queueing model with unreliable service station and multiple adaptive delayed vacations from the perspective of reliability research. Following problems will be discussed...This paper considers the discrete-time GeoX/G/1 queueing model with unreliable service station and multiple adaptive delayed vacations from the perspective of reliability research. Following problems will be discussed: 1) The probability that the server is in a "generalized busy period" at time n; 2) The probability that the service station is in failure at time n, i.e., the transient unavailability of the service station, and the steady state unavailability of the service station; 3) The expected number of service station failures during the time interval (0, hi, and the steady state failure frequency of the service station; 4) The expected number of service station breakdowns in a server's "generalized busy period". Finally, the authors demonstrate that some common discrete-time queueing models with unreliable service station are special cases of the model discussed in this paper.展开更多
In 1985, Bollinger firstly introduced a repairable system model——a strict consecutive-k-out-of-n: F systems(abbreviated to Bollinger model) in terms ofa nonrepairable system 'consecutive-k-out-of-n: F systems...In 1985, Bollinger firstly introduced a repairable system model——a strict consecutive-k-out-of-n: F systems(abbreviated to Bollinger model) in terms ofa nonrepairable system 'consecutive-k-out-of-n: F systems'. However, some conditions in Bollinger modal were assumed too ideally to be used in engineering. For instance, some states (e.g. FGFFFFFFF, n=9, k=2) have already made the system dislocated, but by the assumptions in展开更多
This paper deals with a production-inventory system in which there are amachine consisting of multiple unreliable units and a storage facility of fixed capacity. Theproduct produced is stored in the storage facility. ...This paper deals with a production-inventory system in which there are amachine consisting of multiple unreliable units and a storage facility of fixed capacity. Theproduct produced is stored in the storage facility. The demand process for product is acompound Poisson process. We assume that the demand-size distributions are arbitrary,and the unsatisfied demand is backlogged rather than lost. Our main results are to provean existence theorem on stationary distribution of the slack capacity and to derive anexpression of its stationary distribution function.展开更多
In order to improve performance and robustness of clustering,it is proposed to generate and aggregate a number of primary clusters via clustering ensemble technique.Fuzzy clustering ensemble approaches attempt to impr...In order to improve performance and robustness of clustering,it is proposed to generate and aggregate a number of primary clusters via clustering ensemble technique.Fuzzy clustering ensemble approaches attempt to improve the performance of fuzzy clustering tasks.However,in these approaches,cluster(or clustering)reliability has not paid much attention to.Ignoring cluster(or clustering)reliability makes these approaches weak in dealing with low-quality base clustering methods.In this paper,we have utilized cluster unreliability estimation and local weighting strategy to propose a new fuzzy clustering ensemble method which has introduced Reliability Based weighted co-association matrix Fuzzy C-Means(RBFCM),Reliability Based Graph Partitioning(RBGP)and Reliability Based Hyper Clustering(RBHC)as three new fuzzy clustering consensus functions.Our fuzzy clustering ensemble approach works based on fuzzy cluster unreliability estimation.Cluster unreliability is estimated according to an entropic criterion using the cluster labels in the entire ensemble.To do so,the new metric is dened to estimate the fuzzy cluster unreliability;then,the reliability value of any cluster is determined using a Reliability Driven Cluster Indicator(RDCI).The time complexities of RBHC and RBGP are linearly proportional with thnumber of data objects.Performance and robustness of the proposed method are experimentally evaluated for some benchmark datasets.The experimental results demonstrate efciency and suitability of the proposed method.展开更多
This paper mainly investigates the connectivity of the unreliable sensor grid network. We consider an unreliable sensor grid network with mn nodes placed in a certain planar area A, and we assume that each node has in...This paper mainly investigates the connectivity of the unreliable sensor grid network. We consider an unreliable sensor grid network with mn nodes placed in a certain planar area A, and we assume that each node has independent failure probability p and has the same transmission range R. This paper presents a new method for calculating the connectivity probability of the network, which uses thorough mathematical methods to derive the relationship among the network connectivity probability, the probability that a node is "failed" (not active), the numbers of node, and the node's transmission range in unreliable sensor networks. Our approach is more useful and efficient for given problem and conditions. Such as the numerical calculating results indicate that, for a 100×100 size sensot network, if node failure probability is bounded 0.5%, even if the transmission range is small (such as R = 10), we can still maintain very high connectivity probability (reach 95.8%). On the other hand, the simulation results show that building high connectivity probability is entirely possible on unreliable sensor grid networks.展开更多
As a popular distributed machine learning framework,wireless federated edge learning(FEEL)can keep original data local,while uploading model training updates to protect privacy and prevent data silos.However,since wir...As a popular distributed machine learning framework,wireless federated edge learning(FEEL)can keep original data local,while uploading model training updates to protect privacy and prevent data silos.However,since wireless channels are usually unreliable,there is no guarantee that the model updates uploaded by local devices are correct,thus greatly degrading the performance of the wireless FEEL.Conventional retransmission schemes designed for wireless systems generally aim to maximize the system throughput or minimize the packet error rate,which is not suitable for the FEEL system.A novel retransmission scheme is proposed for the FEEL system to make a tradeoff between model training accuracy and retransmission latency.In the proposed scheme,a retransmission device selection criterion is first designed based on the channel condition,the number of local data,and the importance of model updates.In addition,we design the air interface signaling under this retransmission scheme to facilitate the implementation of the proposed scheme in practical scenarios.Finally,the effectiveness of the proposed retransmission scheme is validated through simulation experiments.展开更多
文摘Several conclusions on minimal cutset are proposed, from which a new algorithm is deduced to evaluate the unreliability of flow networks. Beginning with one unreliability product of the network, disjointed unreliability products are branched out one by one, every of which is selected from the network minimal cutsets. Finally the unreliability of the network is obtained by adding all these unreliability products up.
文摘The work deals with the development of analytical model of multichannel technical queuing system with unreliable servers and input memory where server failure flows and incoming request flows comply with Poissonian laws, while the flows of failed facilities repairs and flows of incoming requests comply with exponential laws of probability distribution. Random process of system change-over is a Markovian process with continuous time and discrete states. Relations binding basic parameters and output characteristics of the system indicated are obtained as probabilities of system staying in the given moment in one of the possible states. The proposed model is the most generalized compared to some models known in literature which could be considered as special cases of the considered model.
文摘The work is dedicated to the development of analytical model of probability estimation of reliability, productivity, quality and efficiency of functioning of the complex technical queuing system consisting of the arbitrary number of marked groups of the service devises (channels, facilities, servers) differing with reliable characteristics (parameters of refusals and restorations) of forming their composition (also of arbitrary number) marked, identical, unreliable and restorable serving channels in which for serving come in requirements with intensities depending on marking of channels. In the considered system it is supposed that the currents of refusals of serving devices and currents of coming requirements are subdued to Poisson, and the currents of restorations of refused devices and the currents of services of coming requirements—exponential laws of distribution of probabilities. A stochastic process of transfers of a system by that is Markovian process with continuous time and discrete states. Correlations linking the basic parameters and exit characteristics of the systems of the pointed out type are obtained in a view of probabilities of the system location in the given moment of time in one of the possible states.
基金supported in part by the National Natural Science Foundation of China (61933007,62273087,U22A2044,61973102,62073180)the Shanghai Pujiang Program of China (22PJ1400400)+1 种基金the Royal Society of the UKthe Alexander von Humboldt Foundation of Germany。
文摘This paper concerns ultimately bounded output-feedback control problems for networked systems with unknown nonlinear dynamics. Sensor-to-observer signal transmission is facilitated over networks that has communication constraints.These transmissions are carried out over an unreliable communication channel. In order to enhance the utilization rate of measurement data, a buffer-aided strategy is novelly employed to store historical measurements when communication networks are inaccessible. Using the neural network technique, a novel observer-based controller is introduced to address effects of signal transmission behaviors and unknown nonlinear dynamics.Through the application of stochastic analysis and Lyapunov stability, a joint framework is constructed for analyzing resultant system performance under the introduced controller. Subsequently, existence conditions for the desired output-feedback controller are delineated. The required parameters for the observerbased controller are then determined by resolving some specific matrix inequalities. Finally, a simulation example is showcased to confirm method efficacy.
文摘Based on the narrative theory of Shlomith Rimmon-Kenan,the present paper will analyze the close connection between the choice and order of the focalizers and the themes of the novel to show that they are chosen and arranged deliberately and accorded to its themes.
基金supported by the National Natural Science Foundation of China(No.52107072)the Natural Science Foundation of Chongqing(No.CSTB2022NSCQ-MSX0811).
文摘For conventional power systems,the forced outage of components is the major cause of load shedding.Unreliability tracing is utilized to allocate the total system load-shedding risk among individual components in ac-cordance with their different contributions.Therefore,critical components are identified and pertinent measures can be taken to improve system reliability.The integra-tion of wind power introduces additional risk factors into power systems,causing previous unreliability tracing methods to become inapplicable.In this paper,a novel unreliability tracing method is proposed that considers both aleatory and epistemic uncertainties in wind power output and their impacts on power system load-shedding risk.First,modelling methods for wind power output considering aleatory and epistemic uncertainties and component outages are proposed.Then,a variance-based index is proposed to measure the contributions of indi-vidual risk factors to the system load-shedding risk.Fi-nally,a novel unreliability tracing framework is devel-oped to identify the critical factors that affect power sys-tem reliability.Case studies verify the ability of the pro-posed method to accurately allocate load-shedding risk to individual risk factors,thus providing decision support for reliability enhancement.
文摘Since its publication, Wuthering Heights has won great popularity home and abroad for the complexity and delicacy of the narration. However, the story is not true as the unreliability of its narrator is obvious as far as it is judged by Rimmon-Kenan's theory of narrative unreliability.
基金Great Technology Innovation of Gansu Province,China (No.2GS063-A52-005-01)Natural Science Foundation of Gansu Province,China (No.3ZS062-B25-034)Research Item of Education Department of Gansu Province,China (No.0703-06)
文摘Different from traditional aggregation method, the unreliable buffers are originally considered and a more general aggregation method is offered, in which not only the unreliable buffers are considered, but also the probabilities of system states are obtained by a discrete model rather than the continuous flow model of unreliable manufacturing systems. The solution technique is offered to get the system sate probabilities. The method advances the traditional system aggregation techniques. Numerical results specify the extended aggregation method and also show that the unreliable limited buffers have a strong impact on the efficiency of the production lines.
文摘Alice Munro,a famous Canadian Canadian short-story writer.She gained the Nobel Prize for Literature in 2013.Munro’s works focus on women and adolescents.She also writes about the illness and love of the elderly.“The Bear Came over the Mountain”is one of them.In this story,Munro adopts unreliable narration to depict love between Grant and Fiona.This paper aims to study the love writing and its unreliable narration in this story.Based on the text of love writing,this paper analyzes the specific strategies of unreliable narration.The author believes that the unreliable narration of the love text in the story can be divided into the unreliable narration of character type and information type.Through analysis of these two types of narration in the story,special meaning of unreliable narration to describe love can be found.Besides,Munro’s description also contains her own insight of love:the course of true love does not always run smooth.
文摘Based on rhetorical research methods of the unreliability,the paper intends to explore the unreliable narrative strategies of the narrator in Grace Paley's The Loudest Voice from the perspectives of the Wayne Booth's criterion of the distance between the narrator and the implied author and James Phelan's extension of unreliability on the basis of classical rhetorical narratology,point⁃ing out that the unreliability serves as the narrative trap which is set up to reveal the inner theme of the work:"The loudest voice"-what the protagonist thought she certainly possessed was only her illusion instead of the truth,and Eastern European Jewish com⁃munity was de facto marginalized by the mainstream culture at that time.
文摘The Tell-Tale Heart is a short story by Edgar Allan Poe. The story is first-person narrative of a narrator who murdered an old man with a clouded eye. This paper aims at identifying the speaker"I"as an unreliable narrator through analyzing the motivation, process and confession of the crime. It is found out that the narrator symbolizes man of evil, while, the old man's vulture eye symbolizes virtue. It's a story about the conflict between evil and virtue.
文摘As an encyclopedic novel and the summit of Chinese classical literary creation,Hongloumeng has not received due critical attention to its unusual narrative style,let alone abundant unreliable narrative.From unreliable narration of narrator and character,this research probes into effective translation strategies to achieve a balance between source text and target text,in light of a comparative analysis of typical illustrations taken from A Dream of Red Mansions and The Story of the Stone.
基金the Natural Sciences and Engineering Research Council(NSERC)of Canada。
文摘Cyber-physical systems(CPSs)have emerged as an essential area of research in the last decade,providing a new paradigm for the integration of computational and physical units in modern control systems.Remote state estimation(RSE)is an indispensable functional module of CPSs.Recently,it has been demonstrated that malicious agents can manipulate data packets transmitted through unreliable channels of RSE,leading to severe estimation performance degradation.This paper aims to present an overview of recent advances in cyber-attacks and defensive countermeasures,with a specific focus on integrity attacks against RSE.Firstly,two representative frameworks for the synthesis of optimal deception attacks with various performance metrics and stealthiness constraints are discussed,which provide a deeper insight into the vulnerabilities of RSE.Secondly,a detailed review of typical attack detection and resilient estimation algorithms is included,illustrating the latest defensive measures safeguarding RSE from adversaries.Thirdly,some prevalent attacks impairing the confidentiality and data availability of RSE are examined from both attackers'and defenders'perspectives.Finally,several challenges and open problems are presented to inspire further exploration and future research in this field.
文摘Fault tree analysis is an effective method for predicting the reliability of a system. It gives a pictorial representation and logical framework for analyzing the reliability. Also, it has been used for a long time as an effective method for the quantitative and qualitative analysis of the failure modes of critical systems. In this paper, we propose a new general coverage model (GCM) based on hardware independent faults. Using this model, an effective software tool can be constructed to detect, locate and recover fault from the faulty system. This model can be applied to identify the key component that can cause the failure of the system using failure mode effect analysis (FMEA).
基金supported in part by the National Natural Science Foundation of China under Grant Nos. 71171138,70871084the Specialized Research Fund for the Doctoral Program of Higher Education of China under Grant No.200806360001
文摘This paper considers the discrete-time GeoX/G/1 queueing model with unreliable service station and multiple adaptive delayed vacations from the perspective of reliability research. Following problems will be discussed: 1) The probability that the server is in a "generalized busy period" at time n; 2) The probability that the service station is in failure at time n, i.e., the transient unavailability of the service station, and the steady state unavailability of the service station; 3) The expected number of service station failures during the time interval (0, hi, and the steady state failure frequency of the service station; 4) The expected number of service station breakdowns in a server's "generalized busy period". Finally, the authors demonstrate that some common discrete-time queueing models with unreliable service station are special cases of the model discussed in this paper.
文摘In 1985, Bollinger firstly introduced a repairable system model——a strict consecutive-k-out-of-n: F systems(abbreviated to Bollinger model) in terms ofa nonrepairable system 'consecutive-k-out-of-n: F systems'. However, some conditions in Bollinger modal were assumed too ideally to be used in engineering. For instance, some states (e.g. FGFFFFFFF, n=9, k=2) have already made the system dislocated, but by the assumptions in
文摘This paper deals with a production-inventory system in which there are amachine consisting of multiple unreliable units and a storage facility of fixed capacity. Theproduct produced is stored in the storage facility. The demand process for product is acompound Poisson process. We assume that the demand-size distributions are arbitrary,and the unsatisfied demand is backlogged rather than lost. Our main results are to provean existence theorem on stationary distribution of the slack capacity and to derive anexpression of its stationary distribution function.
文摘In order to improve performance and robustness of clustering,it is proposed to generate and aggregate a number of primary clusters via clustering ensemble technique.Fuzzy clustering ensemble approaches attempt to improve the performance of fuzzy clustering tasks.However,in these approaches,cluster(or clustering)reliability has not paid much attention to.Ignoring cluster(or clustering)reliability makes these approaches weak in dealing with low-quality base clustering methods.In this paper,we have utilized cluster unreliability estimation and local weighting strategy to propose a new fuzzy clustering ensemble method which has introduced Reliability Based weighted co-association matrix Fuzzy C-Means(RBFCM),Reliability Based Graph Partitioning(RBGP)and Reliability Based Hyper Clustering(RBHC)as three new fuzzy clustering consensus functions.Our fuzzy clustering ensemble approach works based on fuzzy cluster unreliability estimation.Cluster unreliability is estimated according to an entropic criterion using the cluster labels in the entire ensemble.To do so,the new metric is dened to estimate the fuzzy cluster unreliability;then,the reliability value of any cluster is determined using a Reliability Driven Cluster Indicator(RDCI).The time complexities of RBHC and RBGP are linearly proportional with thnumber of data objects.Performance and robustness of the proposed method are experimentally evaluated for some benchmark datasets.The experimental results demonstrate efciency and suitability of the proposed method.
基金Supported by the National Natural Science Foundation of China(90412012) the Natural Science Foundation of Guangdong Province andthe Post-doctoral Science Foundation of China
文摘This paper mainly investigates the connectivity of the unreliable sensor grid network. We consider an unreliable sensor grid network with mn nodes placed in a certain planar area A, and we assume that each node has independent failure probability p and has the same transmission range R. This paper presents a new method for calculating the connectivity probability of the network, which uses thorough mathematical methods to derive the relationship among the network connectivity probability, the probability that a node is "failed" (not active), the numbers of node, and the node's transmission range in unreliable sensor networks. Our approach is more useful and efficient for given problem and conditions. Such as the numerical calculating results indicate that, for a 100×100 size sensot network, if node failure probability is bounded 0.5%, even if the transmission range is small (such as R = 10), we can still maintain very high connectivity probability (reach 95.8%). On the other hand, the simulation results show that building high connectivity probability is entirely possible on unreliable sensor grid networks.
文摘As a popular distributed machine learning framework,wireless federated edge learning(FEEL)can keep original data local,while uploading model training updates to protect privacy and prevent data silos.However,since wireless channels are usually unreliable,there is no guarantee that the model updates uploaded by local devices are correct,thus greatly degrading the performance of the wireless FEEL.Conventional retransmission schemes designed for wireless systems generally aim to maximize the system throughput or minimize the packet error rate,which is not suitable for the FEEL system.A novel retransmission scheme is proposed for the FEEL system to make a tradeoff between model training accuracy and retransmission latency.In the proposed scheme,a retransmission device selection criterion is first designed based on the channel condition,the number of local data,and the importance of model updates.In addition,we design the air interface signaling under this retransmission scheme to facilitate the implementation of the proposed scheme in practical scenarios.Finally,the effectiveness of the proposed retransmission scheme is validated through simulation experiments.