On Queue-Length Information when Customers Travel to a Queue

Author(s):  
Refael Hassin ◽  
Ricky Roet-Green

Problem definition: We consider a service system in which customers must travel to the queue to be served. In our base model, customers observe the queue length and then decide whether to travel. We also consider alternative information models and investigate how the availability of queue-length information affects customer-equilibrium strategies, throughput, and social welfare. Academic/practical relevance: A common assumption in queueing models is that once a customer decides to join the queue, joining is instantaneous. This assumption does not fit real-life settings, where customers possess online information about the current wait time at the service, but while traveling to the service, its queue length may change. Motivated by this realistic setting, we study how queue-length information prior to traveling affects customers’ decision to travel. Methodology: We prove that a symmetric equilibrium exists in our base model. We perform the calculation numerically as a result of the model complexity, which is due to the fact that the arrival rate to the traveling queue depends on the current state of the service queue, and vice versa. The alternative models are tractable, and we present their analytical solution. Results: When customers can observe the service-queue length prior to traveling, their probability of traveling is monotonically nonincreasing with the observed queue length. We find that customers may adopt a generalized mixed-threshold equilibrium strategy: Travel when observing short queue lengths, avoid traveling when observing long queue lengths, and mix between traveling and not traveling when observing intermediate queue lengths, with a decreasing probability of traveling. Managerial implications: Our results imply that when system congestion is high, the provider can increase throughput by disclosing the queue-length information, whereas at low congestion, the provider benefits from concealing the information. With respect to social welfare, queue-length information prior to departure is beneficial when congestion is at intermediate to high levels and yields the same social welfare otherwise.

1968 ◽  
Vol 5 (3) ◽  
pp. 591-606 ◽  
Author(s):  
G. F. Newell

The arrival rate of customers to a service facility is assumed to have the form λ(t) = λ(0) — βt2 for some constant β. Diffusion approximations show that for λ(0) sufficiently close to the service rate μ, the mean queue length at time 0 is proportional to β–1/5. A dimensionless form of the diffusion equation is evaluated numerically from which queue lengths can be evaluated as a function of time for all λ(0) and β. Particular attention is given to those situations in which neither deterministic queueing theory nor equilibrium stochastic queueing theory apply.


Author(s):  
Ricky Roet-Green ◽  
Aditya Shetty

Problem definition: We consider the problem faced by a welfare-maximizing service provider who must make a decision on how to split a fixed quantity of resources between two variants of the service: a standard variant and an expedited variant. The service is mandatory, but customers can choose between the two variants. Choosing the expedited variant requires enrollment that incurs a fixed cost per period. Customers are strategic and have the same cost of waiting but are heterogeneous in the rate at which they use the service. Academic/practical relevance: The option of expedited security at U.S. airports (TSA PreCheck) is an instance where this problem arises. As has been the case with the PreCheck program, providers that offer expedited service may face criticism from customers, with the main concern being that the diversion of resources to expedited services increases wait time for regular customers. This has important policy implications for the provider, especially a government organization such as the TSA. Existing literature has focused on service differentiation as a means to maximize profit or overall social welfare, but its effect on individual customers has received little attention. Methodology: We find customer’s equilibrium decisions for any allocation choice made by the provider. Using the equilibrium result, we solve for the allocation choice that maximizes social welfare. Results: Even when customers behave strategically, an expedited service offered in parallel to a standard service cannot only increase overall welfare, but also do so for each customer individually. We also find that in a scenario where some customers lose out because of the expedited service, improving the efficiency of the expedited service is more effective than decreasing the enrollment cost to help those who are worse off. Managerial implications: The gains from offering expedited service do not have to come at the expense of regular customers. When they do, we provide recommendations for which decision levers are most effective at making the system fair.


1968 ◽  
Vol 5 (03) ◽  
pp. 591-606 ◽  
Author(s):  
G. F. Newell

The arrival rate of customers to a service facility is assumed to have the formλ(t) =λ(0) —βt2for some constantβ.Diffusion approximations show that forλ(0) sufficiently close to the service rateμ, the mean queue length at time 0 is proportional toβ–1/5. A dimensionless form of the diffusion equation is evaluated numerically from which queue lengths can be evaluated as a function of time for allλ(0) andβ.Particular attention is given to those situations in which neither deterministic queueing theory nor equilibrium stochastic queueing theory apply.


2017 ◽  
Vol 33 (4) ◽  
pp. 765 ◽  
Author(s):  
Jin Kyung Kwak

In this study, we investigate the effect of having express checkout lanes in retail stores. Express checkout lanes are being used to reduce expected wait time of small-buying customers, but their operational effect has not been analyzed so far. By comparing the wait time and the queue length of the two scenarios (universal checkout lanes only and separated checkout lanes with express counters) via simulation, we have found that the average wait time of the separated checkout lanes may not be shorter than that of universal checkout lanes. This may be due to that the effect of pooling servers decreases as the number of servers being pooled at each checkout set decreases. The queue length of express checkout lanes may be shorter than that of universal checkout lanes, but in some cases, the average queue length of separated checkout lanes is longer than that of universal checkout lanes, probably due to the effect of pooling servers. By conducting a computational study, we have observed that the effect of pooling servers decreases with customer arrival rate, decreases with regular checkout duration, and slightly increases with regular checkout time variability. These results give us an insight on when the express checkout counters can be effective in retail service operations.


Author(s):  
Vito Tanzi

This book deals with practical or real life aspects of public finance. It focuses on the growth in the activities of governments, in a world that expects more than in the past from governments. The book focuses on the growing complexity in both the work of the private market and that of the public sector. It stresses that part of the growing complexity is due to the more ambitious role that governments tried to play today, while part is due to choices made by governments, so that complexity may be partly avoidable. This was important in the different pursuit of social welfare by different countries. Complexity has increased opportunities for abuses, for rent seeking, and for mistakes in policies. It may also have increased the attraction of populist policies that claim to offer magical or easy solutions to problems. A major conclusion of the book is that the objective of simplicity in laws and in policies should be given more importance by both economists and governments.


Forecasting ◽  
2021 ◽  
Vol 3 (2) ◽  
pp. 322-338
Author(s):  
Marvin Carl May ◽  
Alexander Albers ◽  
Marc David Fischer ◽  
Florian Mayerhofer ◽  
Louis Schäfer ◽  
...  

Currently, manufacturing is characterized by increasing complexity both on the technical and organizational levels. Thus, more complex and intelligent production control methods are developed in order to remain competitive and achieve operational excellence. Operations management described early on the influence among target metrics, such as queuing times, queue length, and production speed. However, accurate predictions of queue lengths have long been overlooked as a means to better understanding manufacturing systems. In order to provide queue length forecasts, this paper introduced a methodology to identify queue lengths in retrospect based on transitional data, as well as a comparison of easy-to-deploy machine learning-based queue forecasting models. Forecasting, based on static data sets, as well as time series models can be shown to be successfully applied in an exemplary semiconductor case study. The main findings concluded that accurate queue length prediction, even with minimal available data, is feasible by applying a variety of techniques, which can enable further research and predictions.


Author(s):  
Weixin Shang ◽  
Gangshu (George) Cai

Problem definition: Few papers have explored the impact of price matching negotiation (PM), in which a channel matches its price with the resulting wholesale price bargained by another channel, on firms’ performances, consumer welfare, and social welfare, with and without supply chain coordination. Academic/practical relevance: Negotiation has been widely seen in determining both uniform and discriminatory wholesale prices, which affect outcomes of competitive supply chain practices. Methodology: To characterize the PM mechanism, we use game theory and Nash bargaining theory to compare PM with simultaneous negotiation (SN) through a common-seller two-buyer differentiated Bertrand competition model. Results: Our analysis reveals that PM can benefit the seller but hurt all buyers, which is at odds with some fair wholesale pricing clauses intending to protect buyers. Under coordination with side payments, however, all firms can conditionally benefit more from PM than from SN. Despite firms’ gains, PM leads to less consumer utility and social welfare compared with SN, unless the second buyer in PM is considerably less powerful than the first buyer. Coordination further worsens PM’s negative impact on consumer utility and social welfare. Moreover, the existence of a spot market can increase the wholesale price in PM, hurting buyers, consumers, and society. Furthermore, the qualitative results about PM remain robust under an alternative disagreement point for PM, multiple buyers, and other extensions. Managerial implications: This paper delivers insights on when price matching in supply chain wholesale price negotiation can benefit a seller, buyers, consumers, and society in a variety of scenarios. It advocates how managers can use PM to their own advantages and provides rationale to decision makers for policy regulations regarding wholesale pricing.


Author(s):  
Tianqin Shi ◽  
Nicholas C. Petruzzi ◽  
Dilip Chhajed

Problem definition: The eco-toxicity arising from unused pharmaceuticals has regulators advocating the benign design concept of “green pharmacy,” but high research and development expenses can be prohibitive. We therefore examine the impacts of two regulatory mechanisms, patent extension and take-back regulation, on inducing drug manufacturers to go green. Academic/practical relevance: One incentive suggested by the European Environmental Agency is a patent extension for a company that redesigns its already patented pharmaceutical to be more environmentally friendly. This incentive can encourage both the development of degradable drugs and the disclosure of technical information. Yet, it is unclear how effective the extension would be in inducing green pharmacy and in maximizing social welfare. Methodology: We develop a game-theoretic model in which an innovative company collects monopoly profits for a patented pharmaceutical but faces competition from a generic rival after the patent expires. A social-welfare-maximizing regulator is the Stackelberg leader. The regulator leads by offering a patent extension to the innovative company while also imposing take-back regulation on the pharmaceutical industry. Then the two-profit maximizing companies respond by setting drug prices and choosing whether to invest in green pharmacy. Results: The regulator’s optimal patent extension offer can induce green pharmacy but only if the offer exceeds a threshold length that depends on the degree of product differentiation present in the pharmaceutical industry. The regulator’s correspondingly optimal take-back regulation generally prescribes a required collection rate that decreases as its optimal patent extension offer increases, and vice versa. Managerial implications: By isolating green pharmacy as a potential target to address pharmaceutical eco-toxicity at its source, the regulatory policy that we consider, which combines the incentive inherent in earning a patent extension on the one hand with the penalty inherent in complying with take-back regulation on the other hand, serves as a useful starting point for policymakers to optimally balance economic welfare considerations with environmental stewardship considerations.


Author(s):  
Juyuan Yin ◽  
Jian Sun ◽  
Keshuang Tang

Queue length estimation is of great importance for signal performance measures and signal optimization. With the development of connected vehicle technology and mobile internet technology, using mobile sensor data instead of fixed detector data to estimate queue length has become a significant research topic. This study proposes a queue length estimation method using low-penetration mobile sensor data as the only input. The proposed method is based on the combination of Kalman Filtering and shockwave theory. The critical points are identified from raw spatiotemporal points and allocated to different cycles for subsequent estimation. To apply the Kalman Filter, a state-space model with two state variables and the system noise determined by queue-forming acceleration is established, which can characterize the stochastic property of queue forming. The Kalman Filter with joining points as measurement input recursively estimates real-time queue lengths; on the other hand, queue-discharging waves are estimated with a line fitted to leaving points. By calculating the crossing point of the queue-forming wave and the queue-discharging wave of a cycle, the maximum queue length is also estimated. A case study with DiDi mobile sensor data and ground truth maximum queue lengths at Huanggang-Fuzhong intersection, Shenzhen, China, shows that the mean absolute percentage error is only 11.2%. Moreover, the sensitivity analysis shows that the proposed estimation method achieves much better performance than the classical linear regression method, especially in extremely low penetration rates.


Author(s):  
Emran Al Otaibi ◽  
Mohammed Refaei ◽  
Nadia Nassif ◽  
Anas Naqawa

Roundabouts have faced a huge development in terms of designing and operation, the reason behind that is to get the most safe and functional design. The functionality is affected by different factors e.g. line width, diameter of the roundabout etc., when the capacity of the roundabout is fully utilized, queue length starts to form in the different approaches, which indicates of a minor or major issue that should be studied. This paper discusses the different factors affecting the queue length of an approach on the roundabout (Al Falah roundabout), after obtaining the data, regression analysis was done to provide a model that can be used for estimating the volume capacity ratio from queue lengths or vice versa. Two other methods were used to compare the obtained model (HCM 2010 Method and Two Minute Rule Method), in addition to a field data collection of the actual timing needed to pass that queue length, which was assigned as the true value of the models and comparing depending on it. Finally, the discussion of the term paper, will include the different concepts of advanced statistical analysis, the will (as expected) contain different types of distributions and the coloration between the keys of the roundabouts design, and will study the limitation and how it can be improved in future.


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