Abstract: We investigate using smartphone WiFi signals to track human queues, which are common in many business areas such as retail stores, airports, and theme parks. Real-time monitoring of such queues would enable a wealth of new applications, such as bottleneck analysis, shift assignments, and dynamic workflow scheduling. We take a minimum infrastructure approach and thus utilize a single monitor placed close to the service area along with transmitting phones. Our strategy extracts unique features embedded in signal traces to infer the critical time points when a person reaches the head of the queue and finishes service, and from these inferences we derive a person's waiting and service times. We develop two approaches in our system, one is directly feature-driven and the second uses a simple Bayesian network. Extensive experiments conducted both in the laboratory as well as in two public facilities demonstrate that our system is robust to real-world environments. We show that in spite of noisy signal readings, our methods can measure service and waiting times to within a $10$ second resolution.

Abstract: New variable speed limit (VSL) schemes are developed based on the Kinematic Wave theory to increase freeway bottleneck discharge rates under two scenarios: (i) steady queue and (ii) oscillatory queue. The key principle is to impose VSL control some distance upstream of a bottleneck to starve the inflow to the bottleneck and dissipate the queue. Once the queue near the bottleneck vanishes, another less restrictive VSL is imposed upstream to (i) resolve the heavy queue generated by the first VSL and (ii) regulate the inflow to the bottleneck to sustain the stable maximum bottleneck discharge rate and prevent traffic breakdown. Several strategies are developed for each scenario ranging from the simplest strategy that maximizes the delay saving to more sophisticated strategies for upstream queue management. An analysis of the model parameters suggests that a wide range of the first speed limit (to clear the queue around the bottleneck) can be imposed to realize significant delay savings.

Abstract: We study a double-sided queue with batch arrivals and abandonment. There are two types of customers, patient ones who queue but may later abandon, and impatient ones who depart immediately if their order is not filled. The system matches units from opposite sides of the queue based on a first-come first-served policy. The model is particularly applicable to a class of alternative trading systems called crossing networks that are increasingly important in the operation of modern financial markets. We characterize, in closed form, the steady-state queue length distribution and the system-level average system time and fill rate. These appear to be the first closed-form results for a double-sided queuing model with batch arrivals and abandonment. For a customer who arrives to the system in steady state, we derive formulae for the expected fill rate and system time as a function of her order size and deadline. We compare these system-and customer-level results for our model that captures abandonment in aggregate, to simulation results for a system in which customers abandon after some random deadline. We find close correspondence between the predicted performance based on our analytical results and the performance observed in the simulation. Our model is particularly accurate in approximating the performance in systems with low fill rates, which are representative of crossing networks.

Abstract: A QoS management scheme for SDN. Network resource availability of routers and switches are maintained in a central resource database of a SDN controller. The SDN controller performs resource reservation, admission control and route calculation. When a flow is admitted or completed, the resource database is updated accordingly. Dynamic queue mapping for QoS routing in SDN is also provided. For a traffic flow with a certain traffic description and delay requirement, the queue mapping protocol dynamically assigns the flow to different priority queues at different switches along its routing path. Compared with the static mapping of a flow to a specified priority queue, the disclosed mapping is more flexible and uses network resources more efficiently.

Abstract: This paper deals with traffic signal control with finite queue capacities in a discrete-time and stochastic setting. A so-called “pressure releasing policy” (PRP) is introduced to optimally release traffic pressure at every time slot, where the traffic pressure at each intersection incorporates knowledge of turning ratios and information of neighboring and ingress queues. PRP does not require knowledge of arrival rates. Moreover, it employs a set of weights satisfying a given condition to handle downstream queue spillover, and an algorithm is provided to generate one possible set of weights. Define the throughput region as the closure of the set of all arrival rate vectors that can be stably supported over the network under the assumption on infinite queue capacities. It is shown that PRP under finite queue capacities can still achieve the closed-loop stability with a reduction on the throughput region. The reduction is a function of weights and internal queue capacities, and PRP with finite but sufficiently large internal queue capacities can be arbitrarily close to recovering the throughput region.

Abstract: Cloud computing realizes a utility computing paradigm by offering shared resources through an Internet-based computing. However, how a system control can enhance profit and simultaneously satisfy the service level agreements (SLAs) has become one of the major interests for cloud providers. In this paper, a cloud server farm provided with finite capacity is modeled as an queuing system. Revenue losses are estimated according to the system controls and impatient customer behaviors. Three important issues are solved in this paper. First, a profit function is developed in which both the system blocking loss and the user abandonment loss are evaluated in total revenue. A tradeoff between meeting system performances and reducing operating costs is conducted. Second, the effects of system capacity control and utilization on various performances of waiting time, loss probability, and final arrival rate are demonstrated. Finally, the proposed optimal profit control (OPC) policy allows a cloud provider to make the optimal decision in the number of servers and system capacity, so as to maximize profit. As compared to a system without applying the OPC policy, enhancing providers’ profit and improving system performances can be obtained.

Abstract: Customer impatience has a very negative impact on the queueing system under investigation. If we talk from business point of view, the firms lose their potential customers due to customer impatience which affects their business as a whole. If the firms employ certain customer retention strategies then there are chances that a certain fraction of impatient customers can be retained in the queueing system. A reneged customer may convinced to stay in the queuing system for his further service with some probability, say and he may abandon the queue without receiving the service with probability . A finite waiting space Markovian single-server queueing model with discouraged arrivals, reneging and retention of reneged customers is studied. The steady state solution of the model is derived iteratively. The measures of effectiveness of the queuing model are also obtained. The cost-profit analysis of the model is also carried out. Some important queuing models are derived as special cases of this model.

Abstract: The derivation of structural properties for unbounded jump Markov processes cannot be done using standard mathematical tools, since the analysis is hindered due to the fact that the system is not uniformizable. We present a promising technique, a smoothed rate truncation method, to overcome the limitations of standard techniques and allow for the derivation of structural properties. We introduce this technique by application to a processor sharing queue with impatient customers that can retry if they renege. We are interested in structural properties of the value function of the system as a function of the arrival rate.

Abstract: The Price of Anarchy (PoA) is a measure for the loss of optimality due to decentralized behavior. It has been studied in many settings but, surprisingly, not in the most fundamental queueing system involving customers' decisions, namely, the single server Markovian queue. We find that the loss of efficiency in such systems is bounded by 50% in most practical cases, in which the arrival rate of the customers is significantly lower than the service rate. We also find that the loss of efficiency has an interesting behavior in two aspects: first, it sharply increases as the arrival rate comes close to the service rate; second, it becomes unbounded exactly when the arrival rate is greater than the service rate, a surprising behavior because the system is always stable. Knowing these bounds is important for the queue controller, for example when considering an investment in added service capacity.

Abstract: Motivated by large-scale service systems with network structure, we introduced in a previous paper a time-varying open network of many-server fluid queues with customer abandonment from each queue and time-varying proportional routing among the queues, and showed how performance functions can be determined. The deterministic fluid model serves as an approximation for the corresponding non-Markovian stochastic network of many-server queues with Markovian routing, experiencing periods of overloading at the queues. In this paper we develop a new algorithm for the previous model and generalize the model to include non-exponential service-time distributions. In this paper we report results of implementing the algorithms and studying their computational complexity. We also conduct simulation experiments to confirm that the algorithms are effective in computing the performance functions and that these performance functions provide useful approximations for the corresponding stochastic models.

Abstract: Nowadays people spend a substantial amount of time waiting in different places such as supermarkets and amusement parks. Detecting the status of queuing may benefit both users and business. In this paper, we present QueueSense, a queuing recognition system on mobile phones to assist in a queue management system. QueueSense extracts features of queuing behavior and classifies queueing via collaboration among people waiting in line. It measures the disparity of people in different lines using relative position changing rate and partitions different queues using a hierarchical clustering approach. We implement a prototype of QueueSense on Android platforms using widely available multi-modal sensors and it is the first queue detection system on mobile phones. We conduct real-world experiments at a dining hall and a supermarket near a university campus. Through implementation and evaluation, we demonstrate that QueueSense is capable of detecting waiting lines that occur in our daily lives with high accuracy.

Abstract: Customer impatience has become a threat to the business world. Firms employ various customer retention strategies to retain their impatient (or reneged) customers. Customer retention mechanisms may help to retain some or all impatient customers. Further, due to unsatisfactory service, customers may rejoin a queue immediately after departure. Such cases are referred to as feedback customers. Kumar and Sharma [7] take this situation into account and study an M/M/1/N feedback queuing system with retention of reneged customers. They obtain only the steady-state solution for this model. In this paper we extend the work in [7] by performing an economic analysis of the model. We develop a model for the costs incurred and perform the appropriate optimization. The optimum system capacity and optimum service rate are obtained.

Abstract: In this paper, we are interested in improving the performance of TCP flows over wireless networks with a given constructive intersession network coding scheme. We are motivated by the observation that TCP does not fully exploit the potential of the underlying network coding opportunities. In order to improve the performance of TCP flows over coded wireless networks, without introducing changes to TCP itself, we propose a network-coding aware queue management scheme (NCAQM) that is implemented at intermediate network coding nodes and bridges the gap between network coding and TCP rate control. The design of NCAQM is grounded on the network utility maximization (NUM) framework and includes the following mechanisms. NCAQM: 1) stores coded packets at intermediate nodes in order to use the buffer space more efficiently; 2) determines what fraction of the flows should be coded together; and 3) drops packets at intermediate nodes so that it matches the rates of parts of different TCP flows that are coded together. We demonstrate, via simulation, that NCAQM significantly improves TCP throughput compared to TCP over baseline queue management schemes.

Abstract: We study the problem of optimally controlling the use of sleep states in an energy-aware M/G/1 queue. In our model, we consider a family of policies where the server upon becoming idle can wait for a random period before entering, potentially randomly, any of a finite number of possible sleep states to save energy. The server becomes busy again after a possibly random number of jobs have arrived. However, jobs are served only after a random setup time. This kind of an energy-aware queuing system has been analyzed in recent papers under specific assumptions regarding the cost metrics and the distributions of the random variables. In this paper, we consider an essentially more general model. Notably we show that the optimal control of the idle time and sleep states is deterministic and does not benefit from randomization: either the system only uses the idle state and no sleep states, or the idle state is not used at all and the server immediately goes to some fixed sleep state and waits until a fixed number of jobs have arrived before starting the setup. We prove this result for two popular cost metrics, namely weighted sum of energy and response time (ERWS) and their product ERP.

Abstract: Systems and methods are disclosed for scheduling a plurality of tasks for execution on one or more processors. An example method includes obtaining a counter value of a counter. The method also includes for each work queue of a plurality of work queues, identifying an execution period of the respective work queue and comparing a counter value to an execution period of the respective work queue. Each work queue includes a set of tasks and is defined by an execution period at which to run the respective set of queued tasks. The method further includes selecting, based on the comparing, a subset of the plurality of work queues. The method also includes scheduling a set of tasks of slower frequency queued in a selected work queue for execution on one or more processors before a set of tasks queued in a non-selected work queue. The work items may be scheduled in O(1) because the design inherently prioritizes the tasks based on the urgency of their completion, and may do so by resetting a work queue pointer.

Abstract: In a restaurant waiting for service is a common phenomenon for the customer. Restaurant owners are not concerned about the matter of waiting customer though they do not want their customer would go another competitor's door. There are several determining factors for a restaurant to be considered as a good or a bad one. Taste, cleanliness, the restaurant layout and settings are some of the most important factors. These factors, when managed carefully, will be able to attract plenty of customers, However, there is also another factor that needs to be considered especially when the restaurant has already succeeded in attracting customers. This factor is the customers queuing time. Queuing theory is the study of queue or waiting lines. Some of the analysis that can be derived using queuing theory include the expected waiting time in the queue, the average time in the system, the expected queue length, the expected number of customers served at one time, the probability of balking customers, as well as the probability of the system to be in certain states, such as empty or full. Hence, queuing theory is suitable to be applied in a restaurant setting since it has an associated queue or waiting line where customers who cannot be served immediately have to queue (wait) for service. Researchers have previously used queuing theory to model the restaurant operation reduce cycle time in a busy fast food restaurant as well as to increase throughput and efficiency. In this study, the average service time, average idle time, and average waiting time at cash counter are measured.

Abstract: A queue is a line of people or things to be handled in a sequential order. It is a sequence of objects that are waiting to be processed. Queuing theory is the study of queues for managing process and objects. Simulation has been applied successfully for modeling small and large complex systems and understanding queuing behavior. Analysis of the models helps to increases the performance of the system. In this paper we analyze various models of the Single server queuing system with necessaryimplementation using Matlab Software.

Abstract: A method in a network node that includes a host and an accelerator, includes holding a work queue that stores work elements, a notifications queue that stores notifications of the work elements, and control indices for adding and removing the work elements and the notifications to and from the work queue and the notifications queue, respectively. The notifications queue resides on the accelerator, and at least some of the control indices reside on the host. Messages are exchanged between a network and the network node using the work queue, the notifications queue and the control indices.

Abstract: We consider a two-channel queuing system with unreliable servers which fail alternately for modeling of hybrid communication systems, which have a millimeter-wave (71–76 GHz, 81–86 GHz) radio channel as a backup communication channel. The stationary distribution of the system states and the most important performance characteristics were obtained.

Abstract: Queues with Markovian arrival and service processes, i.e., MAP/MAP/1 queues, have been useful in the analysis of computer and communication systems and different representations for their stationary sojourn time and queue length distribution have been derived. More specifically, the class of MAP/MAP/1 queues lies at the intersection of the class of QBD queues and the class of semi-Markovian queues. While QBD queues have a matrix exponential representation for their queue length and sojourn time distribution of order N and N2, respectively, where N is the size of the background continuous time Markov chain, the reverse is true for a semi-Markovian queue. As the class of MAP/MAP/1 queues lies at the intersection, both the queue length and sojourn time distribution of a MAP/MAP/1 queue has an order N matrix exponential representation. The aim of this article is to understand why the order N2 distributions of the sojourn time of a QBD queue and the queue length of a semi-Markovian queue can be reduced to an o...

Abstract: In this letter, we consider a cognitive scenario where an energy harvesting secondary user (SU) shares the channel with a primary user (PU). The SU is equipped with two antennas. It maintains a finite capacity energy queue and two infinite capacity data queues: one for storing its own data packets and the other for storing the primary undelivered data packets. The PU com- municates with its destination whenever it has data at its queue head. During idle sessions of the PU, if the secondary energy queue maintains at least K packets, the SU employs the Alamouti coding scheme over two of its data packets. The optimization problem for secondary throughput maximization is stated under the stability of all queues in the network and a specific end-to-end queueing delay for the primary packets. Index Terms—Cooperative communications, energy harvesting, energy packets, energy queue, Markov chain, Alamouti.

Abstract: In this paper, we consider the balking behavior of customers in an M/G/1 queueing system with a removable server under N-policy, where the server may be turned off when no customers are present, and be turned on when the queue length reaches size $N$. Arriving customers decide whether to join the system or balk, based on a linear reward-cost structure that incorporates their desire for service, as well as their unwillingness for waiting. For the unobservable and partially observable queues, we first analyze the stationary behavior of the system; then derive the equilibrium mixed strategies and compare them to the socially optimal strategies. We take the number $N$ as a decision variable and discuss the optimal operations policy in equilibrium states. Finally, we present two examples to demonstrate some of the phenomena in the considered models.

Abstract: A long queue of vehicles at the gate of a marine terminal is a common traffic phenomenon in a port-city, which sometimes causes problems in urban traffic. In order to be able to solve this issue, we firstly need accurate models to estimate such a vehicle queue length. In this paper, we compare the existing methods in a case study, and evaluate their advantages and disadvantages. Particularly, we develop a simulation-based regression model, using the micro traffic simulation software PARAMIC. In simulation, it is found that the queue transient process follows a natural logarithm curve. Then, based on these curves, we develop a queue length estimation model. In the numerical experiment, the proposed model exhibits better estimation accuracy than the other existing methods

Abstract: A paired queue apparatus and method comprising request and response queues wherein queue head and tail pointer update values are communicated through an enhanced pointer word data format providing pointer indicator information and optional auxiliary information in a single transfer, wherein auxiliary information provides additional system communication without consuming additional bandwidth. Auxiliary information is optionally contained in a response data entry written to a response queue or in a request entry written to a request queue.

Abstract: For maintaining the service quality of working place, some kinds of arriving customers control policy are needed. This paper investigates a randomised arriving control policy of finite capacity queuing system with an unreliable server. In the investigated system, when the number of customers reaches the system’s capacity, further arriving customers are not allowed to enter the system. As the queue length decreases to a predefined threshold value, customers may either be allowed entering the system with an exponential startup time or the customers are still unable to enter the system. For such a system, we develop the steady-state solutions and some important system characteristics, such as the probability that the server is busy, effective arrival rate, expected waiting time in the system, etc. We also develop a cost model to determine the optimal control policy at a minimum cost. A sensitivity analysis is also conducted to investigate the effects of changes in the system parameters on the expected cost f...

Abstract: Methods and systems for implementing input/output management in a distributed strict queue are disclosed. A plurality of messages are distributed to a plurality of queue servers based on strict order parameters for the messages. Messages that share a value for the strict order parameter are distributed to the same queue server. The messages are enqueued at the queue servers. Messages that share a value for the strict order parameter are enqueued in a strict order based on the time of receipt at the queue server. One or more queue clients are configured to attempt message processing for the enqueued messages. Network interactions between the queue clients and one or more external components are configured to be routed through a network proxy.

Abstract: This paper is a study of staff issues at the bank, ICBC China. Due to extra and imbalanced staff, the system was idle most of the time. By using the qualitative approach, M/M/s queuing model and discrete event simulation, the staff was sub-optimized. First, observation of the system was conducted and recorded using the existing operations system used by the bank. Arrival time of customers, service time, and the waiting time customers are willing to wait are all included in the data collection. Second, we analyzed the inter arrival time and service time by using the quantitative method and forecast the improvement in the system. We find out that the utilization of the system was very ineffective. Next, we suggested qualitative approach in the designing of queuing system of the bank. Finally, building and validation of a computer simulation model of a bank queuing system was conducted by using POM-QM software. A quantitative analysis and simulation was conducted and sub-optimized the system. The resulting design has a fewer number of service representatives, higher utilization and a waiting time within the limit of the customer's expected time.