This article examines wafer lots scheduling in the diffusion area in semiconductor manufacturing.The diffusion area comprises multiple tool groups.Each of them contains non-identical semiconductor tools.All tools can ...This article examines wafer lots scheduling in the diffusion area in semiconductor manufacturing.The diffusion area comprises multiple tool groups.Each of them contains non-identical semiconductor tools.All tools can process multiple wafer lots simultaneously,and wafer lots processed together in a tool are called a wafer batch.Besides,each wafer lot has specific queue time limits(QTLs)between consecutive processing operations,making the scheduling problem more complicated.To solve it,a discrete backtracking search optimization algorithm(DBSA)is designed for optimizing both wafer lot assignments and wafer batch processing sequences.Once the processing sequence of wafer batches at each tool is determined,a linear program(LP)is built to obtain optimal starting and completion time points of wafer batches while satisfying QTLs.If a schedule is examined to have no feasible solution by the LP,a proposed approach is used to regroup wafer lots to form wafer batches and adjust their processing sequences to potentially make it feasible.Extensive experiments show that DBSA reliably produces feasible schedules and outperforms GA,MixPSO,and GWO,with up to 17.75%,19.19%,and 9.21%reductions in average cycle time,respectively,demonstrating its superiority in both solution quality and practical applicability.展开更多
Queue management and resource allocation play a critical role in enabling cooperative status awareness in vehicular networks.This paper investigates the problem of age of information(AoI)-aware status updates in vehic...Queue management and resource allocation play a critical role in enabling cooperative status awareness in vehicular networks.This paper investigates the problem of age of information(AoI)-aware status updates in vehicle-to-vehicle(V2V)communication,where each vehicle’s status is represented by multiple interdependent packets.To enable fine-grained queue management at the packet level under resource constraints,we formulate a joint optimization problem that simultaneously learns active packet dropping and transmit power control strategies.A hybrid action space is designed to support both discrete dropping decisions and continuous power control.To exploit the graphstructured interference inherent in V2V topology,a graph neural network(GNN)is introduced to aggregate slowly varying large-scale fading,allowing agents to capture topological dependencies implicitly without frequent message exchange.The overall framework is built upon multi-agent proximal policy optimization(MAPPO),with centralized training and decentralized execution(CTDE).Simulations demonstrate that the proposed method significantly reduces average AoI across a wide range of network densities,channel conditions,and traffic loads,consistently outperforming several baselines.展开更多
A gated service single vacation M/G/1 queue with setup and closedown periods,and different customer arrival rates,is studied in this paper.The probability generating function of the number of systems for customers who...A gated service single vacation M/G/1 queue with setup and closedown periods,and different customer arrival rates,is studied in this paper.The probability generating function of the number of systems for customers who are at the initial moment of service period is analyzed by using a total probability theorem,and the stability condition of the system is obtained.The stationary distribution of the queue length is solved by the regeneration cycle method.The stochastic decomposition of queue length in the steady state is calculated,and the service cycle is obtained.Moreover,classified discussions are established in order to solve the steady-state distribution for the waiting time.The variation of system performance indicators with parameters is analyzed by performing numerical experiments.展开更多
This article highlights the relevance of queuing theory as a decision-making tool for solving congestion problems in Guinean ports,particularly of the Autonomous Port of Conakry(APC).Port congestion,which often causes...This article highlights the relevance of queuing theory as a decision-making tool for solving congestion problems in Guinean ports,particularly of the Autonomous Port of Conakry(APC).Port congestion,which often causes delays and additional logistics costs,is a major obstacle to economic development.Using an analytical approach and numerical simulation,the study proposes a realistic model of the operation of the APC container terminal based on the GI/GI/c general queuing model,adapted to complex systems where the distributions of arrivals and services are not necessarily exponential.The Statistical tests performed on empirical data from the year 2023 revealed that ship interarrival times follow a Weibull distribution,while service times are well described by a Gamma distribution.Integrating these distributions into the GI/GI/c framework enabled realistic simulation of the port system’s behavior.The simulation results show an average waiting time of about 1.4 days,a berth occupancy rate of 43%,and a high probability that the system is empty,indicating good operational fluidity.The average observed service rate,estimated at 0.033 ships/hour,demonstrates the port’s ability to efficiently handle vessels without generating congestion.These performances confirm the positioning of the Autonomous Por3t of Conakry,through its container terminal,among the most efficient in West Africa in 2023.The methodological approach developed in this paper,combining probabilistic modeling and simulation,can be extended to other ports in the region for comparative analysis,to support strategic planning of port infrastructure,and to guide decision-making regarding investment and capacity optimization.展开更多
In this paper,we introduce a qualitative analysis in order to study the monotonicity and comparability properties of a single-server retrial queueing model with Bernoulli feedback and negative customers,relative to st...In this paper,we introduce a qualitative analysis in order to study the monotonicity and comparability properties of a single-server retrial queueing model with Bernoulli feedback and negative customers,relative to stochastic orderings.Performance measures of such a system are available explicitly,while their forms are cumbersome(these formulas include integrals of Laplace transform,solutions of functional equations,etc.).Therefore,they are not exploitable from the application point of view.To overcome these difficulties,we present stochastic comparison methods in order to get qualitative estimates of these measures.In particular,we prove the monotonicity of the transition operator of the embedded Markov chain.In addition,we establish conditions for which transition operators as well as stationary probabilities,associated with two embedded Markov chains,having the same structure but with different parameters,are comparable relative to the given stochastic orderings.Further,numerical examples are carried out to illustrate the theoretical results.展开更多
We consider a single server constant retrial queue,in which a state-dependent service policy is used to control the service rate.Customer arrival follows Poisson process,while service time and retrial time are exponen...We consider a single server constant retrial queue,in which a state-dependent service policy is used to control the service rate.Customer arrival follows Poisson process,while service time and retrial time are exponential distributions.Whenever the server is available,it admits the retrial customers into service based on a first-come first-served rule.The service rate adjusts in real-time based on the retrial queue length.An iterative algorithm is proposed to numerically solve the personal optimal problem in the fully observable scenario.Furthermore,we investigate the impact of parameters on the social optimal threshold.The effectiveness of the results is illustrated by two examples.展开更多
A new weighted fair queueing algorithm is proposed, which uses the novel flow-based service ratio parameters to schedule flows. This solves the main drawback of traditional weighted fair queneing algorithms- the packe...A new weighted fair queueing algorithm is proposed, which uses the novel flow-based service ratio parameters to schedule flows. This solves the main drawback of traditional weighted fair queneing algorithms- the packet-based calculation of the weight parameters. In addition, this paper proposes a novel service ratio calculation method and a queue mangement technology. The former adjusts the service ratio parameters adaptively based on the dynamics of the packet lengths and thee solves the unfairness problem induced by the variable packet length. The latter improves the utilization of the server's queue buffer and reduces the delay jitter through restricting the buffer length for each flow.展开更多
This paper presents the derivation of an analytical model for a multi-queue nodes network router, which is referred to as the multi-queue nodes (mQN) model. In this model, expressions are derived to calculate two pe...This paper presents the derivation of an analytical model for a multi-queue nodes network router, which is referred to as the multi-queue nodes (mQN) model. In this model, expressions are derived to calculate two performance metrics, namely, the queue node and system utilization factors. In order to demonstrate the flexibility and effectiveness of the mQN model in analyzing the performance of an mQN network router, two scenarios are performed. These scenarios investigated the variation of queue nodes and system utilization factors against queue nodes dropping probability for various system sizes and packets arrival routing probabilities. The performed scenarios demonstrated that the mQN analytical model is more flexible and effective when compared with experimental tests and computer simulations in assessing the performance of an mQN network router.展开更多
The high-performance computing paradigm needs high-speed switching fabrics to meet the heavy traffic generated by their applications.These switching fabrics are efficiently driven by the deployed scheduling algorithms...The high-performance computing paradigm needs high-speed switching fabrics to meet the heavy traffic generated by their applications.These switching fabrics are efficiently driven by the deployed scheduling algorithms.In this paper,we proposed two scheduling algorithms for input queued switches whose operations are based on ranking procedures.At first,we proposed a Simple 2-Bit(S2B)scheme which uses binary ranking procedure and queue size for scheduling the packets.Here,the Virtual Output Queue(VOQ)set with maximum number of empty queues receives higher rank than other VOQ’s.Through simulation,we showed S2B has better throughput performance than Highest Ranking First(HRF)arbitration under uniform,and non-uniform traffic patterns.To further improve the throughput-delay performance,an Enhanced 2-Bit(E2B)approach is proposed.This approach adopts an integer representation for rank,which is the number of empty queues in a VOQ set.The simulation result shows E2B outperforms S2B and HRF scheduling algorithms with maximum throughput-delay performance.Furthermore,the algorithms are simulated under hotspot traffic and E2B proves to be more efficient.展开更多
This paper develops a QKD (quantum key distribution)-based queueing model to investigate the data delay on QKD link and network, especially that based on trusted relays. It shows the mean packet delay performance of...This paper develops a QKD (quantum key distribution)-based queueing model to investigate the data delay on QKD link and network, especially that based on trusted relays. It shows the mean packet delay performance of the QKD system. Furthermore, it proposes a key buffering policy which could effectively improve the delay performance in practice. The results will be helpful for quality of service in practical QKD systems.展开更多
In this paper, the Geometry/G/1 queueing model with inter-arrival times generated by a geometric(parameter p) distribution according to a late arrival system with delayed access and service times independently distr...In this paper, the Geometry/G/1 queueing model with inter-arrival times generated by a geometric(parameter p) distribution according to a late arrival system with delayed access and service times independently distributed with distribution {gj }, j≥ 1 is studied. By a simple method (techniques of probability decomposition, renewal process theory) that is different from the techniques used by Hunter(1983), the transient property of the queue with initial state i(i ≥ 0) is discussed. The recursion expression for u -transform of transient queue-length distribution at any time point n^+ is obtained, and the recursion expression of the limiting queue length distribution is also obtained.展开更多
In recent years, the transportation system has been faced by increasing challenge in congestion and inefficiency, and research in traffic network has become a significant area of interest. In this paper, we introduce ...In recent years, the transportation system has been faced by increasing challenge in congestion and inefficiency, and research in traffic network has become a significant area of interest. In this paper, we introduce a dynamic-information-based (DIB) queueing strategy into network traffic model under the efficient routing strategy. DIB makes a packet with higher priority to be delivered if there are less packets travelling along its path from the current node to the destination. It is found that, compared with the traditional first-in-first-out (FIFO) queueing strategy, DIB can effectively bMance the traffic load of the system via delaying packets to be delivered to congested nodes. Although the network capacity has no obvious changes, some other indexes which reflect transportation efficiency are efficiently improved in the congestion state. Besides, extensive simulation results and discussions are provided to explain the phenomena. The results may provide novel insights for research on traffic systems.展开更多
Active Queue Management (AQM) is an active research area in the Internet community. Random Early Detection (RED) is a typical AQM algorithm, but it is known that it is difficult to configure its parameters and its ave...Active Queue Management (AQM) is an active research area in the Internet community. Random Early Detection (RED) is a typical AQM algorithm, but it is known that it is difficult to configure its parameters and its average queue length is closely related to the load level. This paper proposes an effective fuzzy congestion control algorithm based on fuzzy logic which uses the pre- dominance of fuzzy logic to deal with uncertain events. The main advantage of this new congestion control algorithm is that it discards the packet dropping mechanism of RED, and calculates packet loss according to a preconfigured fuzzy logic by using the queue length and the buffer usage ratio. Theo- retical analysis and Network Simulator (NS) simulation results show that the proposed algorithm achieves more throughput and more stable queue length than traditional schemes. It really improves a router's ability in network congestion control in IP network.展开更多
Some depression cells with heights lower than their surrounding cells may often be found in Grid-based digital elevation models (DEM) dataset due to sampling errors.The depression-filling algorithm presented by Planch...Some depression cells with heights lower than their surrounding cells may often be found in Grid-based digital elevation models (DEM) dataset due to sampling errors.The depression-filling algorithm presented by Planchon and Darboux works very quickly compared to other published methods.Despite its simplicity and deli-cacy,this algorithm remains difficult to understand due to its three complex subroutines and its recursive execution.Another fast algorithm is presented in this article.The main idea of this new algorithm is as follows:first,the DEM dataset is viewed as an island and the outer space as an ocean;when the ocean level increases,the DEM cells on the island's boundary will be inundated;when a cell is inundated for the first time,its elevation is increased to the ocean level at that moment;after the ocean has inun-dated the entire DEM,all of the depressions are filled.The depression-removing processing is performed using a priority queue.Theoretically,this new algorithm is a fast algorithm despite the fact that it runs more slowly than Planchon and Darboux's method.Its time-complexity in both the worst case and in an average case is O(8nlog 2 (m)),which is close to O(n).The running speed of this algorithm depends mainly on the insertion operation of the priority queue.As shown by the tests,the depres-sion-filling effects of this algorithm are correct and valid,and the overall time consumption of this algorithm is less than twice the time consumed by Planchon & Darboux's method for handling a DEM smaller than 2500×2500 cells.More importantly,this new algorithm is simpler and easier to understand than Planchon and Darboux's method This advantage allows the correct program code to be written quickly.展开更多
By studying the spectral properties of the underlying operator corresponding to the M/G/1 queueing model with optional second service we obtain that the time-dependent solution of the model strongly converges to its s...By studying the spectral properties of the underlying operator corresponding to the M/G/1 queueing model with optional second service we obtain that the time-dependent solution of the model strongly converges to its steady-state solution. We also show that the time-dependent queueing size at the departure point converges to the corresponding steady-state queueing size at the departure point.展开更多
A delayed chasing model is proposed to simulate the chase behavior in the queue, where each member regards the closest one ahead as the target, and the leader is attracted to a target point with slight fluctuation. Wh...A delayed chasing model is proposed to simulate the chase behavior in the queue, where each member regards the closest one ahead as the target, and the leader is attracted to a target point with slight fluctuation. When the initial distances between neighbors possess an identical low value, the fluctuating target of the leader can cause an amplified disturbance in the queue. After a long period of time, the queue recovers the stable state from the disturbance, forming a straightline-like pattern again, but distances between neighbors grow. Whether the queue can keep stable or not depends on initial distance, desired velocity, and relaxation time. Furthermore, we carry out convergence analysis to explain the divergence transformation behavior and confirm the convergence conditions, which is in approximate agreement with simulations.展开更多
In this paper, the transient solutions for M/G/1 queues with single server vacation and multiple server vacations are firstly studied, and the recursion expressions of their Laplace transform are given. Further the di...In this paper, the transient solutions for M/G/1 queues with single server vacation and multiple server vacations are firstly studied, and the recursion expressions of their Laplace transform are given. Further the distribution and stochastic decomposition result of the queue length at a random point in equilibrium are directly obtained from the transient solution. As will be seen this paper provides a intuitive and elegant method for studying transient solutions for M/G/1 queues with single server.展开更多
This paper studies the bulk-arrival M-x/G/1 queue with single server vacation. By introducing the server busy period and using the Laplace transform, the recursion expression of the Laplace transform of the transient ...This paper studies the bulk-arrival M-x/G/1 queue with single server vacation. By introducing the server busy period and using the Laplace transform, the recursion expression of the Laplace transform of the transient queue-length distribution is derived. Furthermore, the distribution and stochastic decomposition result of the queue length at a random point in equilibrium are obtained. Especially some results for the single-arrival M/G/1 queue with single server vacation and bulk-arrival M-x/G/1 queue but with no server vacation can be derived directly by the results obtained in this paper.展开更多
The customer population of entities potentially requesting to join a queue for service often have identical structure, i.e., the same state set and isomorphic transitions. The state size of the automaton modeling a qu...The customer population of entities potentially requesting to join a queue for service often have identical structure, i.e., the same state set and isomorphic transitions. The state size of the automaton modeling a queue will grow rapidly with increase of the size of this population. However, by relabeling the queue arrival events and service events to the same symbols respectively, the automaton model of a queue will be converted to the structure of a buffer, which is proved to be independent of the total size of the customer population, as long as the queue size is held fixed. We propose the model of a dynamic buffer to embody order and shift of a queue. The result is applied to a manufacturing facility with a dynamic buffer to manage the repair of broken down machines.展开更多
This paper discusses the design of the queue for DNA-based computer on the point view of data structure. The nucleotide encodings for all components of the queue are given out formally. The linear double-stranded DNA ...This paper discusses the design of the queue for DNA-based computer on the point view of data structure. The nucleotide encodings for all components of the queue are given out formally. The linear double-stranded DNA molecules are used as the storage structure of the queue, and the basic bio-operations over the queue are described. Furthermore, the comparison between the queue of the electronic computer and that of DNA-based computer are elucidated. To prove the feasibility of our work, nucleotide encodings for an instance of queue are given out. All the biological technology mentioned in this paper can be practically implemented in the laboratory. Based on this work, other data structures could be developed in DNA-based computer.展开更多
基金funded by Science and Technology Development Fund(FDCT),Macao SAR(file Nos.0199/2024/AGJ,0120/2024/RIA2).
摘要This article examines wafer lots scheduling in the diffusion area in semiconductor manufacturing.The diffusion area comprises multiple tool groups.Each of them contains non-identical semiconductor tools.All tools can process multiple wafer lots simultaneously,and wafer lots processed together in a tool are called a wafer batch.Besides,each wafer lot has specific queue time limits(QTLs)between consecutive processing operations,making the scheduling problem more complicated.To solve it,a discrete backtracking search optimization algorithm(DBSA)is designed for optimizing both wafer lot assignments and wafer batch processing sequences.Once the processing sequence of wafer batches at each tool is determined,a linear program(LP)is built to obtain optimal starting and completion time points of wafer batches while satisfying QTLs.If a schedule is examined to have no feasible solution by the LP,a proposed approach is used to regroup wafer lots to form wafer batches and adjust their processing sequences to potentially make it feasible.Extensive experiments show that DBSA reliably produces feasible schedules and outperforms GA,MixPSO,and GWO,with up to 17.75%,19.19%,and 9.21%reductions in average cycle time,respectively,demonstrating its superiority in both solution quality and practical applicability.
基金supported in part by the National Key R&D Program of China under Grant 2024YFE0200700the Key Technologies R&D Program of Jiangsu(Prospective and Key Technologies for Industry)under Grants BE2023022-1 and BE2023022+2 种基金supported in part by the National Natural Science Foundation of China(NSFC)under Grant 62261160576supported in part by the National Natural Science Foundation of China under Grant 62571335in part by the Guangdong Basic and Applied Basic Research Foundation under Grant 2025A1515011948.
摘要Queue management and resource allocation play a critical role in enabling cooperative status awareness in vehicular networks.This paper investigates the problem of age of information(AoI)-aware status updates in vehicle-to-vehicle(V2V)communication,where each vehicle’s status is represented by multiple interdependent packets.To enable fine-grained queue management at the packet level under resource constraints,we formulate a joint optimization problem that simultaneously learns active packet dropping and transmit power control strategies.A hybrid action space is designed to support both discrete dropping decisions and continuous power control.To exploit the graphstructured interference inherent in V2V topology,a graph neural network(GNN)is introduced to aggregate slowly varying large-scale fading,allowing agents to capture topological dependencies implicitly without frequent message exchange.The overall framework is built upon multi-agent proximal policy optimization(MAPPO),with centralized training and decentralized execution(CTDE).Simulations demonstrate that the proposed method significantly reduces average AoI across a wide range of network densities,channel conditions,and traffic loads,consistently outperforming several baselines.
基金supported by the National Natural Science Foundation of China(61973261)the Natural Science Foundation of Jilin Province(20210101151JC).
摘要A gated service single vacation M/G/1 queue with setup and closedown periods,and different customer arrival rates,is studied in this paper.The probability generating function of the number of systems for customers who are at the initial moment of service period is analyzed by using a total probability theorem,and the stability condition of the system is obtained.The stationary distribution of the queue length is solved by the regeneration cycle method.The stochastic decomposition of queue length in the steady state is calculated,and the service cycle is obtained.Moreover,classified discussions are established in order to solve the steady-state distribution for the waiting time.The variation of system performance indicators with parameters is analyzed by performing numerical experiments.
摘要This article highlights the relevance of queuing theory as a decision-making tool for solving congestion problems in Guinean ports,particularly of the Autonomous Port of Conakry(APC).Port congestion,which often causes delays and additional logistics costs,is a major obstacle to economic development.Using an analytical approach and numerical simulation,the study proposes a realistic model of the operation of the APC container terminal based on the GI/GI/c general queuing model,adapted to complex systems where the distributions of arrivals and services are not necessarily exponential.The Statistical tests performed on empirical data from the year 2023 revealed that ship interarrival times follow a Weibull distribution,while service times are well described by a Gamma distribution.Integrating these distributions into the GI/GI/c framework enabled realistic simulation of the port system’s behavior.The simulation results show an average waiting time of about 1.4 days,a berth occupancy rate of 43%,and a high probability that the system is empty,indicating good operational fluidity.The average observed service rate,estimated at 0.033 ships/hour,demonstrates the port’s ability to efficiently handle vessels without generating congestion.These performances confirm the positioning of the Autonomous Por3t of Conakry,through its container terminal,among the most efficient in West Africa in 2023.The methodological approach developed in this paper,combining probabilistic modeling and simulation,can be extended to other ports in the region for comparative analysis,to support strategic planning of port infrastructure,and to guide decision-making regarding investment and capacity optimization.
摘要In this paper,we introduce a qualitative analysis in order to study the monotonicity and comparability properties of a single-server retrial queueing model with Bernoulli feedback and negative customers,relative to stochastic orderings.Performance measures of such a system are available explicitly,while their forms are cumbersome(these formulas include integrals of Laplace transform,solutions of functional equations,etc.).Therefore,they are not exploitable from the application point of view.To overcome these difficulties,we present stochastic comparison methods in order to get qualitative estimates of these measures.In particular,we prove the monotonicity of the transition operator of the embedded Markov chain.In addition,we establish conditions for which transition operators as well as stationary probabilities,associated with two embedded Markov chains,having the same structure but with different parameters,are comparable relative to the given stochastic orderings.Further,numerical examples are carried out to illustrate the theoretical results.
基金supported by the National Natural Science Foundation of China(Grant No.11971486)。
摘要We consider a single server constant retrial queue,in which a state-dependent service policy is used to control the service rate.Customer arrival follows Poisson process,while service time and retrial time are exponential distributions.Whenever the server is available,it admits the retrial customers into service based on a first-come first-served rule.The service rate adjusts in real-time based on the retrial queue length.An iterative algorithm is proposed to numerically solve the personal optimal problem in the fully observable scenario.Furthermore,we investigate the impact of parameters on the social optimal threshold.The effectiveness of the results is illustrated by two examples.
基金National Natural Science Foundation of China ( No.60572157)Sharp Corporation of Japanthe Hi-Tech Research and Development Program(863) of China (No.2003AA123310)
摘要A new weighted fair queueing algorithm is proposed, which uses the novel flow-based service ratio parameters to schedule flows. This solves the main drawback of traditional weighted fair queneing algorithms- the packet-based calculation of the weight parameters. In addition, this paper proposes a novel service ratio calculation method and a queue mangement technology. The former adjusts the service ratio parameters adaptively based on the dynamics of the packet lengths and thee solves the unfairness problem induced by the variable packet length. The latter improves the utilization of the server's queue buffer and reduces the delay jitter through restricting the buffer length for each flow.
摘要This paper presents the derivation of an analytical model for a multi-queue nodes network router, which is referred to as the multi-queue nodes (mQN) model. In this model, expressions are derived to calculate two performance metrics, namely, the queue node and system utilization factors. In order to demonstrate the flexibility and effectiveness of the mQN model in analyzing the performance of an mQN network router, two scenarios are performed. These scenarios investigated the variation of queue nodes and system utilization factors against queue nodes dropping probability for various system sizes and packets arrival routing probabilities. The performed scenarios demonstrated that the mQN analytical model is more flexible and effective when compared with experimental tests and computer simulations in assessing the performance of an mQN network router.
摘要The high-performance computing paradigm needs high-speed switching fabrics to meet the heavy traffic generated by their applications.These switching fabrics are efficiently driven by the deployed scheduling algorithms.In this paper,we proposed two scheduling algorithms for input queued switches whose operations are based on ranking procedures.At first,we proposed a Simple 2-Bit(S2B)scheme which uses binary ranking procedure and queue size for scheduling the packets.Here,the Virtual Output Queue(VOQ)set with maximum number of empty queues receives higher rank than other VOQ’s.Through simulation,we showed S2B has better throughput performance than Highest Ranking First(HRF)arbitration under uniform,and non-uniform traffic patterns.To further improve the throughput-delay performance,an Enhanced 2-Bit(E2B)approach is proposed.This approach adopts an integer representation for rank,which is the number of empty queues in a VOQ set.The simulation result shows E2B outperforms S2B and HRF scheduling algorithms with maximum throughput-delay performance.Furthermore,the algorithms are simulated under hotspot traffic and E2B proves to be more efficient.
基金Project supported by National Fundamental Research Program of China (Grant No 2006CB921900)National Natural Science Foundation of China (Grant Nos 60537020 and 60621064)Knowledge Innovation Project of Chinese Academy of Sciences
摘要This paper develops a QKD (quantum key distribution)-based queueing model to investigate the data delay on QKD link and network, especially that based on trusted relays. It shows the mean packet delay performance of the QKD system. Furthermore, it proposes a key buffering policy which could effectively improve the delay performance in practice. The results will be helpful for quality of service in practical QKD systems.
基金This work was supported by the Scientific Research Fund of Southwestern University of Finance and Economics and the Science Foundation of Sichuan Normal University.
摘要In this paper, the Geometry/G/1 queueing model with inter-arrival times generated by a geometric(parameter p) distribution according to a late arrival system with delayed access and service times independently distributed with distribution {gj }, j≥ 1 is studied. By a simple method (techniques of probability decomposition, renewal process theory) that is different from the techniques used by Hunter(1983), the transient property of the queue with initial state i(i ≥ 0) is discussed. The recursion expression for u -transform of transient queue-length distribution at any time point n^+ is obtained, and the recursion expression of the limiting queue length distribution is also obtained.
基金Supported by the National High Technology Research and Development Program of China under Grant No.2011AA110101the National Natural Science Foundation of China under Grant No.61201314China Scholarship Council
摘要In recent years, the transportation system has been faced by increasing challenge in congestion and inefficiency, and research in traffic network has become a significant area of interest. In this paper, we introduce a dynamic-information-based (DIB) queueing strategy into network traffic model under the efficient routing strategy. DIB makes a packet with higher priority to be delivered if there are less packets travelling along its path from the current node to the destination. It is found that, compared with the traditional first-in-first-out (FIFO) queueing strategy, DIB can effectively bMance the traffic load of the system via delaying packets to be delivered to congested nodes. Although the network capacity has no obvious changes, some other indexes which reflect transportation efficiency are efficiently improved in the congestion state. Besides, extensive simulation results and discussions are provided to explain the phenomena. The results may provide novel insights for research on traffic systems.
基金Supported by the National High Technology Research and Development of China (863 Program) (No.2003AA121560)the High Technology Research and Development Program of Jiangsu Province (No.BEG2003001).
摘要Active Queue Management (AQM) is an active research area in the Internet community. Random Early Detection (RED) is a typical AQM algorithm, but it is known that it is difficult to configure its parameters and its average queue length is closely related to the load level. This paper proposes an effective fuzzy congestion control algorithm based on fuzzy logic which uses the pre- dominance of fuzzy logic to deal with uncertain events. The main advantage of this new congestion control algorithm is that it discards the packet dropping mechanism of RED, and calculates packet loss according to a preconfigured fuzzy logic by using the queue length and the buffer usage ratio. Theo- retical analysis and Network Simulator (NS) simulation results show that the proposed algorithm achieves more throughput and more stable queue length than traditional schemes. It really improves a router's ability in network congestion control in IP network.
基金financially supported by the National Basic Research Program of China (Grant No.2006CB400502)the Promotion of 100 Young Talent Scientist Project of the Chinese Acad-emy of Sciences (8-057493)the Special Meteorology Project(GYHY(QX)2007-6-1)
摘要Some depression cells with heights lower than their surrounding cells may often be found in Grid-based digital elevation models (DEM) dataset due to sampling errors.The depression-filling algorithm presented by Planchon and Darboux works very quickly compared to other published methods.Despite its simplicity and deli-cacy,this algorithm remains difficult to understand due to its three complex subroutines and its recursive execution.Another fast algorithm is presented in this article.The main idea of this new algorithm is as follows:first,the DEM dataset is viewed as an island and the outer space as an ocean;when the ocean level increases,the DEM cells on the island's boundary will be inundated;when a cell is inundated for the first time,its elevation is increased to the ocean level at that moment;after the ocean has inun-dated the entire DEM,all of the depressions are filled.The depression-removing processing is performed using a priority queue.Theoretically,this new algorithm is a fast algorithm despite the fact that it runs more slowly than Planchon and Darboux's method.Its time-complexity in both the worst case and in an average case is O(8nlog 2 (m)),which is close to O(n).The running speed of this algorithm depends mainly on the insertion operation of the priority queue.As shown by the tests,the depres-sion-filling effects of this algorithm are correct and valid,and the overall time consumption of this algorithm is less than twice the time consumed by Planchon & Darboux's method for handling a DEM smaller than 2500×2500 cells.More importantly,this new algorithm is simpler and easier to understand than Planchon and Darboux's method This advantage allows the correct program code to be written quickly.
基金supported by the National Natural Science Foundation of China(11371303)Natural Science Foundation of Xinjiang(2012211A023)Science Foundation of Xinjiang University(XY110101)
摘要By studying the spectral properties of the underlying operator corresponding to the M/G/1 queueing model with optional second service we obtain that the time-dependent solution of the model strongly converges to its steady-state solution. We also show that the time-dependent queueing size at the departure point converges to the corresponding steady-state queueing size at the departure point.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.71071044,71001001,71201041,and 11247291)the Doctoral Program of the Ministry of Education of China(Grant Nos.20110111120023 and 20120111120022)+2 种基金the Postdoctoral Fund Project of China(Grant No.2013M530295)the National Basic Research Program of China(Grant No.2012CB725404)1000 Plan for Foreign Talent,China(Grant No.WQ20123400070)
摘要A delayed chasing model is proposed to simulate the chase behavior in the queue, where each member regards the closest one ahead as the target, and the leader is attracted to a target point with slight fluctuation. When the initial distances between neighbors possess an identical low value, the fluctuating target of the leader can cause an amplified disturbance in the queue. After a long period of time, the queue recovers the stable state from the disturbance, forming a straightline-like pattern again, but distances between neighbors grow. Whether the queue can keep stable or not depends on initial distance, desired velocity, and relaxation time. Furthermore, we carry out convergence analysis to explain the divergence transformation behavior and confirm the convergence conditions, which is in approximate agreement with simulations.
摘要In this paper, the transient solutions for M/G/1 queues with single server vacation and multiple server vacations are firstly studied, and the recursion expressions of their Laplace transform are given. Further the distribution and stochastic decomposition result of the queue length at a random point in equilibrium are directly obtained from the transient solution. As will be seen this paper provides a intuitive and elegant method for studying transient solutions for M/G/1 queues with single server.
基金the National Outstanding Youth Science Foundation !(79725002) the Youth Science Foundation of UEST.
摘要This paper studies the bulk-arrival M-x/G/1 queue with single server vacation. By introducing the server busy period and using the Laplace transform, the recursion expression of the Laplace transform of the transient queue-length distribution is derived. Furthermore, the distribution and stochastic decomposition result of the queue length at a random point in equilibrium are obtained. Especially some results for the single-arrival M/G/1 queue with single server vacation and bulk-arrival M-x/G/1 queue but with no server vacation can be derived directly by the results obtained in this paper.
摘要The customer population of entities potentially requesting to join a queue for service often have identical structure, i.e., the same state set and isomorphic transitions. The state size of the automaton modeling a queue will grow rapidly with increase of the size of this population. However, by relabeling the queue arrival events and service events to the same symbols respectively, the automaton model of a queue will be converted to the structure of a buffer, which is proved to be independent of the total size of the customer population, as long as the queue size is held fixed. We propose the model of a dynamic buffer to embody order and shift of a queue. The result is applied to a manufacturing facility with a dynamic buffer to manage the repair of broken down machines.
基金This work was supportedin part by the National Nature Science Foundation of China (No.60474037and60004006) Programfor NewCentury Excellent Talents in University (NCET04 415) +1 种基金Specialized Research Fund for the Doctoral Programof Higher Educationfrom Educational Committee of China (No.20030255009) the Youth Foundation fromEducational Committee of Anhui Province(No.2005jql043) .
摘要This paper discusses the design of the queue for DNA-based computer on the point view of data structure. The nucleotide encodings for all components of the queue are given out formally. The linear double-stranded DNA molecules are used as the storage structure of the queue, and the basic bio-operations over the queue are described. Furthermore, the comparison between the queue of the electronic computer and that of DNA-based computer are elucidated. To prove the feasibility of our work, nucleotide encodings for an instance of queue are given out. All the biological technology mentioned in this paper can be practically implemented in the laboratory. Based on this work, other data structures could be developed in DNA-based computer.