scholarly journals DYNAMIC ROUTING OF CUSTOMERS WITH GENERAL DELAY COSTS IN A MULTISERVER QUEUING SYSTEM

2009 ◽  
Vol 23 (2) ◽  
pp. 175-203 ◽  
Author(s):  
Nilay Tanik Argon ◽  
Li Ding ◽  
Kevin D. Glazebrook ◽  
Serhan Ziya
Keyword(s):  
Lagrangian Relaxation ◽  
Numerical Study ◽  
Heavy Traffic ◽  
Significant Advance ◽  
Greedy Heuristic ◽  
Single Server ◽  
Long Run ◽  
Central Controller ◽  
Routing Policies ◽  
The Cost

We consider a network of parallel service stations each modeled as a single-server queue. Each station serves its own dedicated customers as well as generic customers who are routed from a central controller. We suppose that the cost incurred by a customer is an increasing function of her time spent in the system. In a significant advance on most previous work, we do not require waiting costs to be convex, still less linear. With the objective of minimizing the long-run average waiting cost, we develop two heuristic routing policies, one of which is based on dynamic programming policy improvement and the other on Lagrangian relaxation. In developing the latter policy, we show that each station is “indexable” under mild conditions for customers’ waiting costs and also prove some structural results on the admission control problem that naturally arises as a result of the Lagrangian relaxation. We then test the performance of our heuristics in an extensive numerical study and show that the Lagrangian heuristic demonstrates a strong level of performance in a range of traffic conditions. In particular, it clearly outperforms both a greedy heuristic, which is a standard proposal in complex routing problems, and a recent proposal from the heavy traffic literature.

scholarly journals On a random interval graph and the maximum throughput rate in the system GI/G/1/0

1991 ◽  
Vol 23 (4) ◽  
pp. 945-956
Author(s):  
Wim M. Nawijn
Keyword(s):  
General Result ◽  
Heavy Traffic ◽  
Interval Graph ◽  
Single Server ◽  
Random Interval ◽  
Loss System ◽  
Maximum Throughput ◽  
Throughput Rate ◽  
Long Run ◽  
Random Intervals

The paper gives an explicit expression for the expectation of the maximum attainable fraction of served customers in the long run for the single-server loss system GI/G/1/0, under the assumption of perfect information regarding the sequences {Xi, i = 1, 2, ·· ·} and {Yi, i = 1, 2, ·· ·} of interarrival times and service times, respectively. A heavy traffic result for this fraction is obtained for the system GI/M/1/0. The general result is based on an analysis of the random interval graph corresponding to the random intervals {[Ti, Ti + Yi), i = 1, 2, ·· ·}, in which {Ti} denotes the sequence of arrival epochs.

scholarly journals On a random interval graph and the maximum throughput rate in the system GI/G/1/0

1991 ◽  
Vol 23 (04) ◽  
pp. 945-956
Author(s):  
Wim M. Nawijn
Keyword(s):  
General Result ◽  
Heavy Traffic ◽  
Interval Graph ◽  
Single Server ◽  
Random Interval ◽  
Loss System ◽  
Maximum Throughput ◽  
Throughput Rate ◽  
Long Run ◽  
Random Intervals

The paper gives an explicit expression for the expectation of the maximum attainable fraction of served customers in the long run for the single-server loss system GI/G/1/0, under the assumption of perfect information regarding the sequences {Xi, i = 1, 2, ·· ·} and {Yi, i = 1, 2, ·· ·} of interarrival times and service times, respectively. A heavy traffic result for this fraction is obtained for the system GI/M/1/0. The general result is based on an analysis of the random interval graph corresponding to the random intervals {[Ti , Ti + Yi ), i = 1, 2, ·· ·}, in which {Ti } denotes the sequence of arrival epochs.

Two competing queues with linear costs and geometric service requirements: the μc-rule is often optimal

1985 ◽  
Vol 17 (1) ◽  
pp. 186-209 ◽  
Author(s):  
J. S. Baras ◽  
A. J. Dorsey ◽  
A. M. Makowski
Keyword(s):  
State Space Model ◽  
Sample Path ◽  
Single Server ◽  
Time Model ◽  
Programming Methodology ◽  
Sample Path Properties ◽  
Long Run ◽  
Markov Decision ◽  
The Cost ◽  
Discounted Criterion

A discrete-time model is presented for a system of two queues competing for the service attention of a single server with infinite buffer capacity. The service requirements are geometrically distributed and independent from customer to customer as well as from the arrivals. The allocation of service attention is governed by feedback policies which are based on past decisions and buffer content histories. The cost of operation per unit time is a linear function of the queue sizes. Under the model assumptions, a fixed prioritization scheme, known as the μc-rule, is shown to be optimal for the expected long-run average criterion and for the expected discounted criterion, over both finite and infinite horizons. Two different approaches are proposed for solving these problems. One is based on the dynamic programming methodology for Markov decision processes, and assumes the arrivals to be i.i.d. The other is valid under no additional assumption on the arrival stream and uses direct comparison arguments. In both cases, the sample path properties of the adopted state-space model are exploited.

Minimizing Mean Response Time In Batch-Arrival Non-Observable Systems With Single-Server FIFO Queues Operating In Parallel

2021 ◽  
Author(s):  
Mikhail Konovalov ◽  
Rostislav Razumchik
Keyword(s):  
Response Time ◽  
Arrival Time ◽  
Time Instant ◽  
Single Server ◽  
State Information ◽  
Mean Response Time ◽  
Routing Policy ◽  
Long Run ◽  
Service Rates ◽  
Routing Policies

Consideration is given to a dispatching system, where jobs, arriving in batches, cannot be stored and thus must be immediately routed to single-server FIFO queues operating in parallel. The dispatcher can memorize its routing decisions but at any time instant does not have any system's state information. The only information available is the batch/job size and inter-arrival time distributions, and the servers' service rates. Under these conditions, one is interested in the routing policies which minimize the job's long-run mean response time. The single-parameter routing policy is being proposed which, according to the numerical experiments, outperforms best routing rules known by now for non-observable dispatching systems: probabilistic and deterministic. Both the batch-wise and job-wise assignments are studied. Extension to systems with unreliable servers is also addressed.

Two competing queues with linear costs and geometric service requirements: the μc-rule is often optimal

1985 ◽  
Vol 17 (01) ◽  
pp. 186-209
Author(s):  
J. S. Baras ◽  
A. J. Dorsey ◽  
A. M. Makowski
Keyword(s):  
State Space Model ◽  
Sample Path ◽  
Single Server ◽  
Time Model ◽  
Programming Methodology ◽  
Sample Path Properties ◽  
Long Run ◽  
Markov Decision ◽  
The Cost ◽  
Discounted Criterion

A discrete-time model is presented for a system of two queues competing for the service attention of a single server with infinite buffer capacity. The service requirements are geometrically distributed and independent from customer to customer as well as from the arrivals. The allocation of service attention is governed by feedback policies which are based on past decisions and buffer content histories. The cost of operation per unit time is a linear function of the queue sizes. Under the model assumptions, a fixed prioritization scheme, known as the μc-rule, is shown to be optimal for the expected long-run average criterion and for the expected discounted criterion, over both finite and infinite horizons. Two different approaches are proposed for solving these problems. One is based on the dynamic programming methodology for Markov decision processes, and assumes the arrivals to be i.i.d. The other is valid under no additional assumption on the arrival stream and uses direct comparison arguments. In both cases, the sample path properties of the adopted state-space model are exploited.

scholarly journals Application of the theory of decision making under risk and uncertainty at modelling of costs

2010 ◽  
Vol 56 (No. 5) ◽  
pp. 201-208 ◽  
Author(s):  
M. Beranová ◽  
D. Martinovičová
Keyword(s):  
Decision Making ◽  
Financial Accounting ◽  
Cost Functions ◽  
Risk And Uncertainty ◽  
Managerial Decision ◽  
Managerial Decision Making ◽  
Bayesian Theorem ◽  
Long Run ◽  
Short Run ◽  
The Cost

The costs functions are mentioned mostly in the relation to the Break-even Analysis where they are presented in the linear form. But there exist several different types and forms of cost functions. Fist of all, it is necessary to distinguish between the short-run and long-run cost function that are both very important tools of the managerial decision making even if each one is used on a different level of management. Also several methods of estimation of the cost function's parameters are elaborated in the literature. But all these methods are based on the past data taken from the financial accounting while the financial accounting is not able to separate the fixed and variable costs and it is also strongly adjusted to taxation in the many companies. As a tool of the managerial decision making support, the cost functions should provide a vision to the future where many factors of risk and uncertainty influence economic results. Consequently, these random factors should be considered in the construction of cost functions, especially in the long-run. In order to quantify the influences of these risks and uncertainties, the authors submit the application of the Bayesian Theorem.

scholarly journals Competing Conventions with Costly Information Acquisition

Games ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 53
Author(s):  
Roberto Rozzi
Keyword(s):  
Information Acquisition ◽  
Evolutionary Model ◽  
Equilibrium Selection ◽  
The Other ◽  
Group Interactions ◽  
Social Coordination ◽  
Long Run ◽  
Stochastic Stability Analysis ◽  
The Stability ◽  
The Cost

We consider an evolutionary model of social coordination in a 2 × 2 game where two groups of players prefer to coordinate on different actions. Players can pay a cost to learn their opponent’s group: if they pay it, they can condition their actions concerning the groups. We assess the stability of outcomes in the long run using stochastic stability analysis. We find that three elements matter for the equilibrium selection: the group size, the strength of preferences, and the information’s cost. If the cost is too high, players never learn the group of their opponents in the long run. If one group is stronger in preferences for its favorite action than the other, or its size is sufficiently large compared to the other group, every player plays that group’s favorite action. If both groups are strong enough in preferences, or if none of the groups’ sizes is large enough, players play their favorite actions and miscoordinate in inter-group interactions. Lower levels of the cost favor coordination. Indeed, when the cost is low, in inside-group interactions, players always coordinate on their favorite action, while in inter-group interactions, they coordinate on the favorite action of the group that is stronger in preferences or large enough.

The Comparison of CFD Flow Field between Slope Solar Energy Power Plant and Traditional Solar Chimney Power Generating Equipment

2013 ◽  
Vol 561 ◽  
pp. 614-619 ◽  
Author(s):  
Qing Ling Li ◽  
Xiao Qing Xie ◽  
Jun Chao ◽  
Xuan Xin ◽  
Yan Zhou
Keyword(s):  
Power Plant ◽  
Velocity Field ◽  
Solar Energy ◽  
Numerical Study ◽  
Solar Chimney ◽  
Heat Collector ◽  
Fluent Software ◽  
Generating Equipment ◽  
The Cost ◽  
Power Generating Equipment

A numerical study with FLUENT software has been carried out as to air performance in the slope solar energy power plant. The velocity field, temperature and pressure fields in the solar chimney, and the simulated result were compared with the simulated result of traditional solar chimney power generating equipment. The simulation results show that distribution of the temperature field and the velocity field in slope solar energy power plant and traditional solar chimney power generating equipment. In the case of the same height, the velocity of traditional is slightly larger than the slope style's, but there is little difference. In order to achieve the same power generation effect, the overall height of slope style is more than the traditional style, but the vertical chimney height of traditional style is greater than the slope style. The cost of construction of vertical chimney is expensive, and many problems have been considered, like radix saposhnikoviae and earthquake prevention, the heat collector also need to be cleaned on time. The slope style can take full advantage of land, the height of vertical chimney will be reduced, so the construction of the chimney will be relatively easy. Rainwater can clean the heat collector when it runs down from it. All things considered. The slope solar energy power plant has more development prospects.

scholarly journals Altruism in behavioural, motivational and evolutionary sense

2019 ◽  
Vol 30 (1) ◽  
pp. 122-134 ◽  
Author(s):  
Bojana Radovanovic
Keyword(s):  
Reproductive Success ◽  
Social Norm ◽  
Moral Principle ◽  
Non Profit ◽  
Altruistic Motivation ◽  
Evolutionary Theories ◽  
Long Run ◽  
Material Benefits ◽  
The Cost ◽  
The Sacrifice

This paper discusses the relations between three forms of altruism: behavioural, evolutionary and motivational. Altruism in a behavioural sense is an act that benefits another person. It can range from volunteering to a charity and helping a neighbour, to giving money to a non-profit organisation or donating blood. People often dedicate their material and nonmaterial resources for the benefit of others to gain psychological, social and material benefits for themselves. Thus, their altruistic acts are driven by egoistic motivation. Also, the final goal of an altruistic act may be the increase in the welfare of a group or adherence to a certain moral principle or a social norm. However, at least sometimes, the welfare of others is the ultimate goal of our actions, when our altruistic acts are performed from altruistic motivation. In evolutionary sense, altruism means the sacrifice of reproductive success for the benefit of other organisms. According to evolutionary theories, behaviour which promotes the reproductive success of the receiver at the cost of the actor is favoured by natural selection, because it is either beneficial for the altruist in the long run, or for his genes, or for the group he belongs to. However, altruism among people emerges as a distinctly human combination of innate and learned behaviours. Not only do we benefit the members of our own group, but we are capable of transcending our tribalistic instincts and putting the benefit of strangers at our own personal expense as our ultimate goal.

Sign in / Sign up

Export Citation Format

Share Document