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
We compare the optimal operating cost of the two bicriterion policies, <p,T> and <p,N>, for an M/G/1 queueing system with second optional service, in which the length of the vacation period is randomly con...We compare the optimal operating cost of the two bicriterion policies, <p,T> and <p,N>, for an M/G/1 queueing system with second optional service, in which the length of the vacation period is randomly controlled either by the number of arrivals during the idle period or by a timer. After all the customers are served in the queue exhaustively, the server immediately takes a vacation and may operate <p,T> policy or <p,N> policy. For the two bicriterion policies, the total average cost function per unit time is developed to search the optimal stationary operating policies at a minimum cost. Based upon the optimal cost the explicit forms for joint optimum threshold values of (p,T) and (p,N) are obtained.展开更多
Watershed management consists of multifunctional activities to manage and address the increasing water resource problems. Ever increasing water demand and rapidly depleting water resources, it has become necessary to ...Watershed management consists of multifunctional activities to manage and address the increasing water resource problems. Ever increasing water demand and rapidly depleting water resources, it has become necessary to develop the adaptation options to recharge groundwater resources. A watershed is a special kind of Common Pool Resources (CPRs);an area is defined by hydrological linkages where optimal management requires coordinating the use of natural resources by public participation. Watershed developments have shown significant positive impacts on water table, perennially of water in wells and water availability especially in semi-arid regions. This paper describes direct and indirect impacts of the watershed activities and benefits of hydrological services dealing with watershed management with future prediction of net irrigation water supply. In the present work, we have also discussed the multiple impacts of watershed of CPRs for improving groundwater and surface water resources.展开更多
This paper studies a single server discrete-time Erlang loss system with Bernoulli arrival process and no waiting space. The server in the system is assumed to provide two different types of services, namely essential...This paper studies a single server discrete-time Erlang loss system with Bernoulli arrival process and no waiting space. The server in the system is assumed to provide two different types of services, namely essential and optional services, to the customer. During the operation of the system, the arrival of the catastrophe will break the system down and simultaneously induce customer to leave the system immediately. Using a new type discrete supplementary variable technique, the authors obtain some performance characteristics of the queueing system, including the steady-state availability and failure frequency of the system, the steady-state probabilities for the server being idle, busy, breakdown and the loss probability of the system etc. Finally, by the numerical examples, the authors study the influence of the system parameters on several performance measures.展开更多
A bulk-arrival single server queueing system with second multi-optional service and unreliable server is studied in this paper. Customers arrive in batches according to a homogeneous Poisson process, all customers dem...A bulk-arrival single server queueing system with second multi-optional service and unreliable server is studied in this paper. Customers arrive in batches according to a homogeneous Poisson process, all customers demand the first ＂essential＂ service, whereas only some of them demand the second ＂multi-optional＂ service. The first service time and the second service all have general distribution and they are independent. We assume that the server has a service-phase dependent, exponentially distributed life time as well as a servicephase dependent, generally distributed repair time. Using a supplementary variable method, we obtain the transient and the steady-state solutions for both queueing and reliability measures of interest.展开更多
This paper studies the procurement management of carbon financial instruments and the production decisions for an emission-dependent remanufacturing firm under service requirements.In the presence of demand uncertaint...This paper studies the procurement management of carbon financial instruments and the production decisions for an emission-dependent remanufacturing firm under service requirements.In the presence of demand uncertainty,carbon emission options are introduced to hedge risks for the firm who purchases carbon financial instruments under a cap-flexible emission trading scheme(ETS)and then conducts remanufacturing.We develop three optimization models to determine the optimal remanufacturing quantity(procurement quantity of carbon financial instruments)maximizing the firm's expected profit under three contracts:a pure wholesale price contract,a pure carbon option contract,and a portfolio contract.Through analyses and comparisons of optimal solutions,we demonstrate the values of introducing carbon options and committing to service levels for the firm.Compared with the other two pure contracts,the portfolio contract makes the firm better off.However,high service requirements may lead to a profit loss to the firm.We generalize to the cases when the yield rate is dependent on the quality of used products,when the yield is stochastic,and when carbon price performs volatility.Discussion of these extensions illuminates how the variability of used product quality,yield rate and carbon price influences the firm's performances.展开更多
基金supported by the National Natural Science Foundation of China(11371303)Natural Science Foundation of Xinjiang(2012211A023)Science Foundation of Xinjiang University(XY110101)
文摘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.
文摘We compare the optimal operating cost of the two bicriterion policies, <p,T> and <p,N>, for an M/G/1 queueing system with second optional service, in which the length of the vacation period is randomly controlled either by the number of arrivals during the idle period or by a timer. After all the customers are served in the queue exhaustively, the server immediately takes a vacation and may operate <p,T> policy or <p,N> policy. For the two bicriterion policies, the total average cost function per unit time is developed to search the optimal stationary operating policies at a minimum cost. Based upon the optimal cost the explicit forms for joint optimum threshold values of (p,T) and (p,N) are obtained.
文摘Watershed management consists of multifunctional activities to manage and address the increasing water resource problems. Ever increasing water demand and rapidly depleting water resources, it has become necessary to develop the adaptation options to recharge groundwater resources. A watershed is a special kind of Common Pool Resources (CPRs);an area is defined by hydrological linkages where optimal management requires coordinating the use of natural resources by public participation. Watershed developments have shown significant positive impacts on water table, perennially of water in wells and water availability especially in semi-arid regions. This paper describes direct and indirect impacts of the watershed activities and benefits of hydrological services dealing with watershed management with future prediction of net irrigation water supply. In the present work, we have also discussed the multiple impacts of watershed of CPRs for improving groundwater and surface water resources.
基金supported by the National Natural Science Foundation of China under Grant No.70871084Specialized Research Fund for the Doctoral Program of Higher Education of China under Grant No. 200806360001the Scientific Research Fund of Sichuan Provincial Education Department under Grant No.10ZA136
文摘This paper studies a single server discrete-time Erlang loss system with Bernoulli arrival process and no waiting space. The server in the system is assumed to provide two different types of services, namely essential and optional services, to the customer. During the operation of the system, the arrival of the catastrophe will break the system down and simultaneously induce customer to leave the system immediately. Using a new type discrete supplementary variable technique, the authors obtain some performance characteristics of the queueing system, including the steady-state availability and failure frequency of the system, the steady-state probabilities for the server being idle, busy, breakdown and the loss probability of the system etc. Finally, by the numerical examples, the authors study the influence of the system parameters on several performance measures.
基金Supported by the National Natural Science Foundation of China (No. 10871020)
文摘A bulk-arrival single server queueing system with second multi-optional service and unreliable server is studied in this paper. Customers arrive in batches according to a homogeneous Poisson process, all customers demand the first ＂essential＂ service, whereas only some of them demand the second ＂multi-optional＂ service. The first service time and the second service all have general distribution and they are independent. We assume that the server has a service-phase dependent, exponentially distributed life time as well as a servicephase dependent, generally distributed repair time. Using a supplementary variable method, we obtain the transient and the steady-state solutions for both queueing and reliability measures of interest.
基金We thank the editor and two anonymous referees for their constructive comments and many valuable suggestions that have significantly improved the quality of this paper.This work has been supported by the National Natural Science Foundation of China(NSFC),under Grant Nos.71971058,71571042,and 71971210.
文摘This paper studies the procurement management of carbon financial instruments and the production decisions for an emission-dependent remanufacturing firm under service requirements.In the presence of demand uncertainty,carbon emission options are introduced to hedge risks for the firm who purchases carbon financial instruments under a cap-flexible emission trading scheme(ETS)and then conducts remanufacturing.We develop three optimization models to determine the optimal remanufacturing quantity(procurement quantity of carbon financial instruments)maximizing the firm's expected profit under three contracts:a pure wholesale price contract,a pure carbon option contract,and a portfolio contract.Through analyses and comparisons of optimal solutions,we demonstrate the values of introducing carbon options and committing to service levels for the firm.Compared with the other two pure contracts,the portfolio contract makes the firm better off.However,high service requirements may lead to a profit loss to the firm.We generalize to the cases when the yield rate is dependent on the quality of used products,when the yield is stochastic,and when carbon price performs volatility.Discussion of these extensions illuminates how the variability of used product quality,yield rate and carbon price influences the firm's performances.
