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Due to unambiguous applications of bulk service vacation queues with set-up time in various fields such as pharmaceutical, aerospace engineering, automobile industries etc., in this article, we analyze an infinite-buffer batch-size-dependent bulk service queue with single and multiple vacations, N-policy and set-up time. Customers/packets/units are served by a single server according to general bulk service (a, b) rule. The service time of a batch dynamically varies with the batch-size and follows the general distribution which covers a large scale of distributions. Firstly, we generate the steady-state system equations. The main intend of this study is to obtain the complete joint distribution of queue-length and server content at service completion epoch, for which the bivariate probability generating function has been derived. We extract the joint distribution which is presented in a quite simple form and using those we find the joint distribution at arbitrary epoch beside some marginal distributions and performance measures. Finally, several numerical examples along with graphical sketches have been provided to verify the analytical results and to provide inner feeling to the system designers. [ABSTRACT FROM AUTHOR]

Torn between desire and hope, patience and impatience, those waiting for change in Morocco have, since independence, been articulating their rejection of the way the queues of dignity and social justice are getting intolerably static and crowded. This article1 reasons with cultural and socio-political gradations of waiting in the Muslim and Moroccan tradition to discuss how the dynamics of waiting and not waiting reflect the poor people’s methods of tolerating or challenging the prevailing truth. We theoretically and empirically make sense of the way political stagnancy and social nothingness culminate into what we call a state of (asitism) or (as-it-is-ism), a proponent as it were of obdurate stagnancy, deferral of personal and collective expectations, and persistence of social plights and economic ills, that are continuously informed and challenged by waiting and non-waiting protocols. To get to grips with asitism as a conceptual tool and ontological phenomenon, this article takes into consideration how and why the subjects revolt, whether it be by seeking migration opportunities to Europe; by illegally crossing the borders; or by otherwise expressing their denunciation of the way politicians seek to dupe them into more waiting. However, even when they refuse to wait for the promises politicians make to be verified as truthful or fake by not taking part in the elections or by boycotting a particular party, we contend that they simply deploy the time they have for a different wait, hence re-organising themselves in a different queuing order. [ABSTRACT FROM AUTHOR]

This paper analyzes the steady state behavior of batch arrival non-Markovian service queue with feedback, balking, reneging, and second optional service (SOS). The steady-state probabilities are computed using the probability generating function. After completing the first essential service (FES), if a customer is unsatisfied with it, he may choose to rejoin the system (feedback), opt for the SOS, or depart from the system with specific probabilities. Once a customer arrives, he decides immediately to join the queue or refuses to join (balking). Furthermore, after joining the queue if a customer does not get service within a specific time, may become impatient, and decide to leave the line without getting any service (reneging). Reneging time follows exponential distribution while service time (FES and SOS) follow general distribution. Also, the cost model was presented to determine the optimal service rates to minimize the expected cost. Finally, various performance measures and numerical illustrations are provided. [ABSTRACT FROM AUTHOR]

In the present investigation, we consider a bulk queue model with the assumption that the server may stop working due to random failure during any stage of the service. As soon as the server fails, it is immediately sent for repair. The server offers all incoming units the first mandatory service and any one of the optional services as per the unit's requirements. For computation purposes, we assume that the server offers m+1 services, of which the first one is essential and the remaining are optional. The server may take a vacation in accordance with the Bernoulli vacation schedule with probability p as soon as both service phases of a unit are completed. As the system empties, the server idles and needs some time to set up before initiating the next service. In order to analyse the model and derive various steady-state queue length distributions, we incorporated the supplementary variables corresponding to service time, vacation time, and repair time and applied the probability generating function technique to determine the various system state distributions. Using these probability distributions, we derive the explicit form of various performance indices. To discuss the validity of the present model, we obtained some well-known results from the queueing literature as a special case of the present model by setting appropriate parameters. Finally, to analyse the sensitivity of several performance indices, a numerical demonstration is provided. [ABSTRACT FROM AUTHOR]

Queues have been at the centre of South Africa's COVID-19 story. National lockdown was declared on 26 March 2020, around the time 'month-end' salaries and government grants are paid out. Within the first few days, reports came of the long lines outside banks and supermarkets, with journalists regularly citing people's failure to 'social distance'. This article uses the queue as an analytic tool to explore the unequal vulnerabilities entailed in the experience of COVID-19 lockdown in South Africa. [ABSTRACT FROM AUTHOR]

This study aims to develop a queuing model at the Commercial Bank of Ethiopia to improve the service quality perceived by customers using a simulation tool. Performance variables that were considered when developing this model are the average waiting time for a client to get service, customer arrival rates, and service time. After the identification of the problem, the service quality of the bank is assessed using a questionnaire that was prepared in SERVQUAL format. The filled-out and returned questionnaires were analyzed using SPSS, and the results show that the service quality of the bank was deemed very low. The recorded data was then ultimately used as a basis for the determination of arrival, service rates, and the distribution function in the simulation input analyzer. The distribution function determined was used as an input for the development of the existing queue model, and based on that, scientific scenarios are adopted from scientific research and further observations at the bank are added to show enhancement of the existing model. The study used four scenarios to test the response group, and one scenario was selected as the best. This has been identified by adding a server to the counters where there is less utilization, that is, servers four and five. As a result, the waiting time has been minimized by 20 minutes under server four and by 83.4 minutes under server five. Also, the number of customers served per day can be increased from 1048 to 1168, which is 11.45% improvement. [ABSTRACT FROM AUTHOR]

The article presents an ethnography of the queue that formed in the Comic Con Experience parking lot on December 6, 2019 to access the Cinemark auditorium panels, held the next day. Based on the article by Leon Mann called Queue Culture: The Waiting Line as a Social System (1969) and on the book Fila e Democracia (2017) by Roberto DaMatta and Alberto Junqueira, this text defines the queue as a space democratic public. The study also understands that it consists of a social practice that generates sociabilities, marked by a sense of community. The article concludes that references to pop culture narratives present in the event and in the queue generate an affective anteriority that, shared between individuals, establishes a "common" that links their behaviors, emotions and affections, as discussed by Muniz Sodré in the book The science of the common: notes on the communicational method (2014). [ABSTRACT FROM AUTHOR]

Mobile network processing and the Edge Computing paradigm can be integrated as a unit called mobile fog computing in fifth-generation networks. Because mobile devices have less computing capacity such as limited CPU power, storage capacity, memory constraints, and limited battery life, therefore, computationally intensive tasks migrate from MDs to MFC. In this paper, we formulate an optimization scheme based on the Greedy Knapsack Offloading Algorithm (GKOA) to minimize the energy consumption of the MDs and save the capacity of limited resources. For resource allocation and dynamic scheduling, we present a dynamic scheduling algorithm based on the priority queue. We design two queues where the tasks with high execution times have the high priority in high time queue and the other, tasks with low execution times have the high priority in low time queue. These two priority queues work together and call as High Low Priority Scheduling (HLPS) model. Numerical results demonstrate the GKOA scheme improves energy efficiency by 19 % , system overhead by 13.87 % , and average delay by 8.5 % on the MD side than local computing. Also, our proposed scheduling algorithm performs optimal results than several benchmark algorithms in terms of waiting time, delay, service level, average response time and the number of scheduled tasks on the MFC side. [ABSTRACT FROM AUTHOR]

The paper deals with an M/M/2 Queueing Model with working vacations and reneging of customers due to impatience. The matrix geometric method is used to find the distribution of the number of customers in the system. A cost function is constructed to obtain the optimal value of the service rate to optimize (minimize) the cost function using the Quadratic Fit Search Method (QFSM). Further, the effects on the system's performance measures using numerical analysis and graphical representation are studied. [ABSTRACT FROM AUTHOR]

The current research article explores a finite capacity discrete-time multiple working vacations queue with impatient clients and congestion dependent service rates. An arriving client can choose either to enter the queue or balk with a certain probability. Due to impatience, he may renege after joining the queue as per geometric distribution. Rather than totally shutting down the service throughout the vacation period, the server functions with a different service rate. The times of services during regular service and during working vacation periods are considered to be geometrically distributed. The vacation periods are also presumed to be geometrically distributed. In addition, the service rates are considered to be dependent on the number of clients in the system during regular service period and during working vacation period. The model's steady-state probabilities are calculated using matrix approach and a recursive solution is also provided. The recursive solution is used for obtaining the corresponding continuous-time results. Various system performance metrics are presented. Finally, the numerical representation of the consequences of the model parameters on the performance metrics is furnished. [ABSTRACT FROM AUTHOR]

The ferry transit system provides a critical transportation link in coastal areas for both residents and tourists. Like signals in a road network, queuing and waiting are unavoidable at ferry terminals. However, a reliable technology does not exist to measure and communicate waiting times. This research tested the feasibility of applying license plate recognition (LPR) technology to track vehicles and estimate waiting times at ferry terminals. The LPR camera sampling rate, capture rate, read rate, and match rate were adopted as measurements of effectiveness. Based on field data collected over a week at one of the busiest ferry terminals in North Carolina, this research revealed that the tested LPR camera had a sampling rate of 84.2%; the average capture rate and read rate were 84.3% and 87%, respectively. The match rate was found to be 79.4%, which is significantly higher than other commonly used data collection technologies such as Bluetooth devices. For the waiting time distribution, this research found that travelers tended to experience long waiting times during midweek days, particularly during the midday period. Additionally, the demand was found to be the primary factor for wait times during the midday peak period, and travelers' arrival time in terms of proximity to the scheduled ferry departure time was recognized as the key factor for waiting time during early morning and later evening nonpeak periods. [ABSTRACT FROM AUTHOR]

Background: Surabaya with a population density, can cause problems if it is not managed properly, one of which is the health sector. Convoluted administrative services and piles of queues at health care facilities are the effects of problems that are often found, this is the reason why e-health is implemented in Surabaya. Objective: to examine the application of e-health and its impact in health care facilities in the city of SurabayaMethods: This research is a literature review study. The data sources come from Google Scholar and the Garuda Portal from the 2016-2022 period. The keywords used are e-health in the city of Surabaya. The overall results of the articles through screening amounted to 15 articles Results:. The history of e-health was created because of the queues that occurred at health care facilities. Indicators show that e-health has an impact on reducing queues at health care facilities if it is not used manually, distribution of infrastructure and socialization also needs to be done more. The existence of assistant officers and training for service officers need to be carried out to support community satisfaction Conclusion: e-health has been implemented in 65 health care facilities, but not all have implemented it well. Some service facilities still apply manually so queues still occur. The impact on service facilities that apply queues can be reduced and make it easier for both the community and service personnel because it is easier to store patient data. Health facilities are advised to innovate socialization so that people are more aware of the existence of e-health. [ABSTRACT FROM AUTHOR]

Dynamic prediction of queues and delays at signalized intersections utilize data obtained from automated traffic sensors as inputs for Intelligent Transportation Systems (ITS) applications. Errors are inevitable during automated data handling, especially when the traffic involved is heterogeneous and lacking in lane discipline. This paper presents a model-based estimation scheme that can handle both mixed traffic conditions and erroneous detector input data to estimate queue and, in turn, delay. The models were developed for Queue within Advance Detector (QWAD) and Queue beyond Advance Detector (QBAD) scenario. The statistical properties of detector errors were incorporated into the estimation scheme, and the scheme was tested for varying traffic conditions. The estimation scheme's performance was evaluated using field data from a signalized intersection in Chennai, India, and simulated data. It is found that the incorporation of statistical properties of detector error allows accurate estimation of queues and delays despite erroneous data input. [ABSTRACT FROM AUTHOR]

The problem faced by a new brand is that JC-Jelly Corner, which is engaged in beverage production, is constrained by data collection in its sales because it cannot disable any drinks that have been successfully sold and is constrained in the queue of ordering customers, which is sometimes when there are many irregular ordering buyers. In this study, a web-based application is needed that can help solve the above problems to be able to manage the existing order queue so that it is more regular in the queue, plus in this case the empty drink stock can be known not to need to directly check the ordered drinks are available or out of stock, to further speed up the ordering process. In the queue setting here using the queue algorithm to set the buyer who first orders he is the one who comes out first, the second buyer who orders then he will wait first until the first buyer is finished being served and so on until there is no longer an order queue. Buyers can only order and see that the order has been processed or is still waiting if the process is complete status is ready, if the drink order has been taken, the status is done. [ABSTRACT FROM AUTHOR]

In modern days waiting time in the traffic signals is one of the major problem met by our society. Queuing theory is the mathematical theory and method of studying queuing system. This paper is an analyses of traffic signals with various time setup and waiting time in the system. Numerical example is illustrated to study the effect of increasing the duration of green signal in the morning session. [ABSTRACT FROM AUTHOR]

In this manuscript, Markovian queueing system with working vacation, Bernoulli schedule interruption, setup time under feedback, reneging of impatient customers, and retention of reneged customers are analyzed. The unsatisfied customers on service completion may either leave the system with probabilities  or may rejoin the queue with complementary probabilities during working vacations and regular service, respectively. The waiting customers in the queue may lose patience due to vacations and decide to leave without getting the service with probability q. They may be retained in the system via some convincing mechanisms with probability (1-q). The mean system length, probability of server in various states, mean sojourn time are obtained using the probability generating function method. The MATLAB software is used for representing the observed behavior graphically. [ABSTRACT FROM AUTHOR]

Trilobites are one of the most important invertebrate clades in the Palaeozoic, with significant disparity in morphology and behaviour, the latter including intriguing instances of queueing. Previous studies employed Computational Fluid Dynamics (CFD) to investigate queuing behaviour in the Devonian trilobite Trimerocephalus chopini and found drag reduction effects. Novel calculations that define a ratio between drag force and Apparent Gravity (W), along with the Submerged Froude Number (Fr sub), however, reveal that the obtained drag force was practically negligible in terms of the underwater mobility of trilobites. A trilobite would start to experience difficulty in forward walking only when the relative flow speed was over 42 cm/s, which is inconsistent with the interpreted palaeoenvironment or the predicted moving speed of trilobites. Nevertheless, according to the proposed cantilever model, a trilobite had the ability to sense very minute change in fluid velocity (>7.16 μm/s). High-sensitivity mechanical sensors distributed along the body, either on the exoskeleton or limbs, empowered queuing individuals to discern the fixed self-similar pattern of the wake generated by their predecessors in the queue. In general, if a trilobite were out of the wake, the asymmetrical velocity and pressure field would aid in repositioning itself, facilitating the maintenance of migratory queues. This permitted blind trilobites to securely sense their companions, compensating for lack of long-range visual capability. This paradigm of force assessment is suitable to Computational Fluid Dynamic analyses in other extinct animal-environment interactions, offering a framework to evaluate whether drags and wakes impact more on organism's mobility (W ≫ 0.1 , Fr sub ≫ 1) or their mechanical sensors, and provides a unique cross-scale insight into animals' adaptation to palaeohydrodynamic variation. • Criteria to assess relative importance of drag force in terms of mobility and mechanosensors. • Wakes in trilobite queues help them positioning. • Wakes have recognizable self-similarity. • Trilobite can sense 7 μm/s variation in fluid speed through setae. • Drag reduction is only needed for high Reynolds and Froude Numbers. [ABSTRACT FROM AUTHOR]

In this study, we analyze a multi-server queueing model with two successive optional services. Each server provides FES as well as two optional services to each arriving customer, for a total of c servers. Every new customer requires the first essential service (FES). The customer may quit the system with probability (1 - r0) or choose optional services supplied by the same server after finishing the FES. With probability r0, customer chooses the first optional service (OS - 1). Following that, the customer has the option of joining the second optional service (OS - 2) with probability r1 or leave the system with probability (1 - r1). We obtain the steady-state probability distributions by applying matrix-geometric method. We also derive a number of performance measures of the queueing model. Sensitivity analysis is used to investigate the impact of various parameters on performance of the queueing model. [ABSTRACT FROM AUTHOR]

This article studies a single server queueing system in which customers arrive according to a batch Markovian arrival process and customers are served in batches of random capacity 'Y' with a minimum threshold value 'a'. The service time of each batch is arbitrarily distributed and independent of service batch size. We first construct the vector difference equations by observing two consecutive departure epochs and then convert them into the vector probability generating function. The queue-length distribution at departure epoch is extracted in terms of roots of the associated characteristic equation. A comparative study is also carried out to compare the roots method with that of the matrix-analytic method. To obtain the queue-length distribution at random epoch, we establish a relationship between the queue-length distributions at departure and random epochs with the help of Markov renewal theory. We obtain the queue-length distribution at prearrival epoch of an arriving batch and the queue-length distribution at post-arrival epoch of a random customer of an arrived batch. Further, we derive the results of some particular well-known queueing models from our model. The results are illustrated by numerical examples for different service-time distributions to show the variation of the key performance measures. [ABSTRACT FROM AUTHOR]

The article examines the use of the queue-jumping metaphor within the Australian press at three key points of asylum seeker arrivals. As a diachronic study, it investigates the development of the metaphor and its utilisation. The article finds that while the metaphor developed at the intersection of political and news discourse, its usage was far from straightforward, often acting as a focus for arguments opposing government policies and rhetoric. Yet the success of the metaphor in shaping the narrative around asylum seekers can be understood through its structuring of a deserving/undeserving dichotomy, aligned with quintessential Australian values, which led to both pro- and anti-government positions being articulated through the context of queue-jumping. [ABSTRACT FROM AUTHOR]

Over the last few years, energy optimization in wireless sensor networks (WSNs) has drawn the attention of both the research community and actual users. Sensor nodes are powered by attached batteries that are considered as a critical aspect of sensor nodes design. Besides, the constraint of the limited battery capacity is associated with the concern on how to reduce the energy consumption of nodes to extend the network lifetime. In this context, the purpose of this study is to implement an adaptive medium access control (MAC) for energy saving and traffic control enhancement. This program was designed to arrange nodes into two priority groups according to their traffic rate and data transmission packet delay. This fuzzy algorithm depends on their queue length where it is implemented into the carrier sense multiple access with collision avoidance (CSMA/CA) algorithm. However, other types of nodes should send their data during the contention-free period with a GTS reallocation scheme. Those nodes are classified as low priority access to the medium, and their data transmission is scheduled using time division multiple access methods. Moreover, this proposed scheme dynamically adjusts the contention access period length to ensure that nodes can complete their data transmission during the same super-frame. Simulation results are done using the network simulator tool (NS-2), and it has improved efficiency regarding the IEEE-802.15.4 standard. [ABSTRACT FROM AUTHOR]

This work quantitatively analyses vessel traffic service (VTS) communications in ports and suggests improvements for more efficient control of the service. For this purpose, analysis of VTS communications was performed on VHF channel 12 in Busan North Port, South Korea. This communications service follows the queue of M/G/1 (the arrivals have a Poisson distribution, the service time is characterized by a general distribution, and with a single server). The degree of congestion of the communication channel was shown as the utilisation rate of the queue, which was 67·7% at peak times and 29·6% at non-peak times. To reduce congestion in the communication channel, we propose to separate the peak time control channel, exclude passing reporting, and decrease the reporting time. With separation of the peak time control channel, the utilisation rate decreased by 41·1%. The utilisation rate decreased by 5·7% when passing reporting was omitted, and by 8·3% when reporting time was reduced by 60%. The results of this study can be used as basic policy data to improve VTS, including reinforcement of the VTS officer's role and adjustment of the control report contents. [ABSTRACT FROM AUTHOR]

Zusammenfassung Das Billardspiel ist über ein halbes Jahrtausend alt. Seine Physik fasziniert die Forschung seit Huygens bis heute. Die aus der Perspektive der Physik entscheidenden Elemente sind der Stoß mit dem Queue, der Kontakt zwischen den Bällen und der Kontakt zwischen Ball und Bande. Gestoßen werden kann die Kugel zentral, ober‐ oder unterhalb ihres Mittelpunkts sowie seitlich versetzt. Davon hängt ihr Verhalten ab, ob sie rollt, gleitet, etwa einen Topspin oder einen sonstigen Effet mitbekommt. Während der Kontakt zwischen zwei Bällen wegen der geringen Reibung wie ein elastischer Stoß behandelbar ist, spielt der Effet beim Kontakt mit der Bande eine wichtige Rolle. Beim Sinai‐Billard besitzt der Tisch runde Ecken oder ein rundes Hindernis, die Folge ist chaotisches Verhalten. Das wurde mit ultrakalten Atomen in entsprechend geformten Lichtpotentialen demonstriert. [ABSTRACT FROM AUTHOR]

This paper studies the beamforming and resource allocation problem in a multiuser full duplex (FD) system with delay-awareness. We design a power-efficient algorithm to minimize the long-term sum transmit power under delay constraints. We do this by jointly optimizing the uplink transmit power and the downlink beamforming vectors while satisfying the long-term stability constraints on the queue buffers for the downlink and uplink users as well as quality of service constraints. Due to the stochastic nature of the problem, we exploit the classic drift-plus-penalty function and subsequently simplify the problem into a difference of convex functions. Building upon the transformed problem, we propose two algorithm designs, one, that exploits the users with good channel conditions for efficient resource allocation, and the other that ensures delay-fairness among all users based on the max-min formulation. Simulation results show significant gains achieved by the proposed FD schemes compared with the baseline HD schemes. [ABSTRACT FROM AUTHOR]

This paper presents a simple procedure to evaluate the actual waiting-time distributions for the first- and an arbitrary-customer of an arrival batch in the D-BMAP/G / 1 queueing system. The analysis is based on the remaining service time as the supplementary variable and the roots of the associated characteristic equation of the vector-generating function of the actual waiting-time distribution. Numerical aspects have been tested for a variety of service-time distribution and a sample of numerical outputs is presented. [ABSTRACT FROM AUTHOR]

Let θ be the unknown parameter for the arrival process in a single queue. The paper discusses the bound for the equivalence of Bayes and maximum likelihood estimator for the parameter θ. Also the bound on the difference of Bayes estimator from its true value is found out. [ABSTRACT FROM AUTHOR]

Problems of large sample estimation for the parameters in a single server queueing set up are discussed. The queueing system is observed over a continuous time interval , where T is determined by a suitable stopping rule. The asymptotic properties of the maximum likelihood estimator from single server queues are studied using the martingale technique. An example with simulation study is given to illustrate the results. [ABSTRACT FROM AUTHOR]

Connection and service request scheduling affects the performance of a mobile relay node (MRN) in a relay-assisted long-term evolution network in terms of crucial quality-of-service (QoS) metrics such as the blocking probability and the system's response time. In this paper, a novel Deadline-constrained Connection and service Request Scheduling (DCRS) scheme is proposed with the objective of improving an MRN's performance in terms of the above-mentioned metrics. In this paper, a stochastic queueing model is formulated for the purpose of capturing the MRN's behavioral dynamics and evaluating its performance as it operates under DCRS. Simulations are conducted in order to verify the model's results’ validity and accuracy. Moreover, the MRN performance achieved under DCRS is compared to that achieved under the typically adopted first-come-first-service (FCFS) scheme. Results indicate that DCRS remarkably outperforms FCFS. [ABSTRACT FROM AUTHOR]

This paper considers an infinite-buffer batch-service queue with Markovian arrival process, generally distributed and batch-size-dependent service time. We obtain a bivariate vector generating function of queue length and server content distribution at departure epoch of a batch. The complete joint distribution of queue length, server content and phase of the arrival process at departure epoch is extracted in terms of roots of the associated characteristic equation. By employing these probability vectors we also perceive the joint distribution at arbitrary and pre-arrival epochs. Our analytic procedure and results are demonstrated using some numerical examples for phase-type as well as deterministic service time distributions with high and low values of model parameters. The occurrence of multiple roots are also investigated in case of phase-type service time distribution. Finally, we also investigate the influence of correlation of the arrival process on the behavior of the system performance. [ABSTRACT FROM AUTHOR]

The contemporary Russian migration regime is grounded in an artificial shortage of legal labour. For migrant workers from 'visa-free' states of the former Soviet Union, becoming and remaining documented requires mastering the queue as a distinct social and institutional form. Exploring the everyday tactics of 'occupying the queue' among migrant workers from Kyrgyzstan, this paper brings an existentially sensitive perspective on migration into conversation with an anthropology of legal time, attentive to the ways in which being 'stuck in motion' emerges through the conjunction of competing tempi of work, life, and legalization. A focus on the queue as social form draws attention to the embodied labour of synchronization: the physical and social effort entailed in integrating the disjunctive temporal regimes of paid work and documentary verification in contexs of legal precarity. In so doing, the article critically interrogates assumptions of 'empty time' in recent anthropological work on waiting. [ABSTRACT FROM AUTHOR]

A queuing system with two incongruent arrivals and services is considered. Two kinds of customers enter the system by Poisson process and the service times are assumed to have general distribution. After first kind service completion, it may feedback to repeat the first service, leave the system or go to give second service. The same policy is applied for the other kind of customer. All stochastic processes involved in this system are independent. We derive the probability generating function for each kind and for the system that yield the performance measures. Some numerical approaches examined the validity of the results. [ABSTRACT FROM AUTHOR]

We consider an infinite buffer single server queue wherein customers arrive according to the batch renewal arrival process and are served in batches following the random serving capacity rule. The service-batch times follow exponential distribution. This model has been studied in the past using the embedded Markov chain technique and probability generating function. In this paper we provide an alternative yet simple methodology to carry out the whole analysis which is based on the supplementary variable technique and the theory of difference equations. The procedure used here is simple in the sense that it does not require the complicated task of constructing the transition probability matrix. We obtain explicit expressions of the steady-state system-content distribution at pre-arrival and arbitrary epochs in terms of roots of the associated characteristic equation. We also present few numerical results in order to illustrate the computational procedure. [ABSTRACT FROM AUTHOR]

Increased delays and reduced speeds in work zones leads to congestion. This can be improved by optimizing the work zone length. The focus of this study is to model work zones using cellular automata model and to find the effects of work zones on traffic flow. The methodology adopted in the study involved creating work-zone on the road by blocking some of the cells and then determining traffic characteristics such as delay and queue lengths for model validation. For this the lateral movement rules of the existing Cellular Automata model were modified in order to replicate the traffic movement near work zones. This model is calibrated and validated using data from work zone observed near a metro rail station in Delhi. From the analysis it was evident that the queue length increased with increase in the length of work zone. Several relationships were tried between delay and work zone length. Among them the rational form was found suitable. [ABSTRACT FROM AUTHOR]

This article focuses on a snacks company located in Medellín (Colombia), which, due to the increase in production due to the high demand for its products, affected the quality and production standards, causing various problems such as delays in the delivery of products, accumulation of raw material among others. In this way, the presented problem was evaluated using a discrete simulation model considering all the variables that intervene in this situation, locating possible bottlenecks that cause the production delay, and in this way the action plan was determined to continue to solve the problem. Taking into account the findings found in the above, we proceeded to establish different scenarios of solution, attacking the different causes of the problem, then these scenarios were evaluated to establish the feasibility of the implementation in the snacks factory, and the results were analyzed found which are relevant to identify the activities that could be intervened to increase the volume of units produced and also provide a solution to the problem. [ABSTRACT FROM AUTHOR]

To effectively enhance the production efficiency of multi-reentrant workshop， the queue constraint was considered where products were processed layer by layer， and then a scheduling method of reentrant hybrid flow shops(RHFS)was proposed based on column generation algorithm. Firstly， a two-stage scheduling model of RHFS was described and a mathematical programming model was built with an objective of minimizing the total completion time. A column generation algorithm was developed and dynamic programming with multiple decision-making was designed to solve each sub-problem. Further， the adaptive accelerating strategy was applied to effectively improve the algorithm convergence. In the process of generating integral solutions by using branch-and-bound method， column pool was built and neighborhood mutation method was emploied. Finally， numerical experiments in different problem scales were carried out to analyze the proposed algorithm. Results verify the validness and feasibility of the proposed algorithm. [ABSTRACT FROM AUTHOR]

In order to increase parallelism via memory width in scalable memory systems, a straightforward approach is to employ larger number of memory controllers (MCs). Nevertheless, a number of researches have pointed out that, even executing bandwidth-bound applications in systems with larger number of MCs, the number of transaction queue entries is under-utilized—namely as shallower transaction queues, which provides an opportunity to power saving. In order to address this challenge, we propose the use of transaction queues with dynamic size that employs the most adequate size, taking into consideration the number of entries utilized while presenting adequate levels of bandwidth and minimizing power. Experimental results show that, while saving up to 75% number of entries, the introduction of dynamic transaction queue mechanism can present savings up to 75% of bandwidth and 20% of rank energy-per-bit reduction compared to systems with 1-2 entries. [ABSTRACT FROM AUTHOR]

To understand crowd evacuation, a model based on a bacterial foraging algorithm (BFA) is proposed in this paper. Considering dynamic and static factors, the probability of pedestrian movement is established using cellular automata. In addition, given walking and queue times, a target optimization function is built. At the same time, a BFA is used to optimize the objective function. Finally, through real and simulation experiments, the relationship between the parameters of evacuation time, exit width, pedestrian density, and average evacuation speed is analyzed. The results show that the model can effectively describe a real evacuation. [ABSTRACT FROM AUTHOR]

Predicting the risk of traffic demands and delays exceeding critical limits at road junctions, airports, hospitals, etc., requires knowing how both mean and variance of queue size vary over time. Microscopic simulation can explore variability but is computationally demanding and gives only sample results. A computationally efficient approximation to the mean is used in many modelling tools, but only empirical extensions for variance in particular situations have been available. The paper derives theoretical formulae for time-dependent and equilibrium variance, believed to be novel and to apply generally to queues covered by the Pollaczek–Khinchin mean formula, and offering possible structural insights. These are applied in an extended approximation giving mutually consistent mean and variance estimates with improved accuracy. Tests on oversaturated peak demand cases are compared with Markov probabilistic simulation, demonstrating accuracy (R2 > 0.99) for typical random, priority-like (M/M/1) and traffic-signal-like (M/D/1) queues. Implications for risk analysis, planning and policy are considered. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the effects of four factors on perceptions of fairness in access to outpatient services: proportions of walk-in versus scheduled registration, consultation queues, regulations for late patients and particular categories of patients getting better access. Methods: A total of 124 young adults were asked to consider nine different scenarios and report their views of the fairness of each one. Results: As regards the balance of types of patients, 60% walk-in registration was seen as fair to both walk-in and scheduled patients. The fairness to both types of patients was higher in the queue with a 1:1 ratio of walk-in to scheduled patients. The policy that a late patient should wait for three on-time patients to be seen was considered to be fair to both on-time and late patients. Immediate consultation for some particular categories of patient (e.g. the elderly) was fair, but for other categories was unfair (e.g. paying an addition amount). Conclusions: Fairness in outpatient care is based on equality and need principles. Shorter waiting time does not mean patients view the system as fairer. [ABSTRACT FROM AUTHOR]

The objects of study of this paper are communication channels in which the dominant type of noise are symbol shifts, the main motivating examples being timing and bit-shift channels. Two channel models are introduced and their zero-error capacities and zero-error-detection capacities determined by explicit constructions of optimal codes. Model A can be informally described as follows: 1) The information is stored in an $n $ -cell register, where each cell is either empty or contains a particle of one of $P $ possible types and 2) due to the imperfections of the device each of the particles may be shifted several cells away from its original position over time. Model B is an abstraction of a single-server queue: 1) The transmitter sends packets from a $P $ -ary alphabet through a queuing system with an infinite buffer and a first-in-first-out service procedure and 2) each packet is being processed by the server for a random number of time slots. More general models including additional types of noise that the particles/packets can experience are also studied, as are the continuous-time versions of these problems. [ABSTRACT FROM AUTHOR]

We present a technique for automatically verifying safety properties of concurrent programs, in particular programs that rely on subtle dependencies of local states of different threads, such as lock-free implementations of stacks and queues in an environment without garbage collection. Our technique addresses the joint challenges of infinite-state specifications, an unbounded number of threads, and an unbounded heap managed by explicit memory allocation. Our technique builds on the automata-theoretic approach to model checking, in which a specification is given by an automaton that observes the execution of a program and accepts executions that violate the intended specification. We extend this approach by allowing specifications to be given by a class of infinite-state automata. We show how such automata can be used to specify queues, stacks, and other data structures, by extending a data-independence argument. For verification, we develop a shape analysis, which tracks correlations between pairs of threads, and a novel abstraction to make the analysis practical. We have implemented our method and used it to verify programs, some of which have not been verified by any other automatic method before. [ABSTRACT FROM AUTHOR]

Wireless Mesh Network (WMN) can provide high bandwidth Internet access to end users. Energy conservation is a key parameter for green and cost effective communication. As energy efficiency has not been given due consideration in WMN by researchers. With increasing interest in WMN, this research presents an energy efficient routing metric by considering energy due to transmission, reception, retransmission, overhearing and queue stability. Results in terms of throughput and energy consumption have been compared with that of standardization arena i.e. airtime link metric. [ABSTRACT FROM AUTHOR]

We consider a batch arrival infinite-buffer single-server queue with generally distributed inter-batch arrival times with arrivals occurring in batches of random sizes. The service process is correlated and its structure is governed by a Markovian service process in continuous time. The proposed analysis is based on roots of the associated characteristic equation of the vector-generating function of system-length distribution at a pre-arrival epoch. We also obtain the steady-state probability distribution at an arbitrary epoch using the classical argument based on Markov renewal theory. Some important performance measures such as the average number of customers in the system and the mean sojourn time have also been obtained. Later, we have established heavy- and light-traffic approximations as well as an approximation for the tail probabilities at pre-arrival epoch based on one root of the characteristic equation. Numerical results for some cases have been presented to show the effect of model parameters on the performance measures. [ABSTRACT FROM AUTHOR]

In this paper, we derive exact large buffer asymptotics for a two-class generalized processor sharing (GPS) model, under the assumption that the input traffic streams generated by both classes correspond to heavy-tailed Lévy processes. Four scenarios need to be distinguished, which differ in terms of (i) the level of heavy-tailedness of the driving Lévy processes as well as (ii) the values of the corresponding mean rates relative to the GPS weights. The derived results are illustrated by two important special cases, in which the queues' inputs are modeled by heavy-tailed compound Poisson processes and by $$\alpha $$ -stable Lévy motions. [ABSTRACT FROM AUTHOR]

The traffic delay at intersections is crucial for the performance of urban traffic system. This paper analytically investigated the minimum traffic delay at a three-phase T-type intersection. We firstly demonstrate that the minimum traffic delay must be achieved on the surface of the 3D space constituted by the three constraints. Next, we prove that the minimum traffic delay must be achieved on the three borderlines of the surface. Finally, we show that the minimum delay is achieved either on one specific borderline or at the vertex of the surface. In the former case, extra green time is needed for the stream with largest demand, while no extra green time should be assigned to any stream in the latter case. [ABSTRACT FROM AUTHOR]

SUMMARY There were 18 electric vehicles, in average, per quick charger (QC), in Japan as of 2012, and this value may increase by a factor of several dozen by 2020. It is, therefore, necessary to model and analyze QC service, identify the causes of wait time, and provide countermeasures to avoid significant QC congestion and to encourage the spread of QC stations. This research analyzed usage data of a QC installed at an existing service area on expressway, and showed the characteristics of QC demand as distribution functions. QC service was modeled as a queuing problem, and simulations were carried out using derived distribution functions. The results showed that the QC station needs additional charger in the case of daily charging times over 10 times. [ABSTRACT FROM AUTHOR]

A protein fold can be viewed as a self-avoiding walk in certain lattice model, and its contact map is a graph that represents the patterns of contacts in the fold. Goldman, Istrail, and Papadimitriou showed that a contact map in the 2D square lattice can be decomposed into at most two stacks and one queue. In the terminology of combinatorics, stacks and queues are noncrossing and nonnesting partitions, respectively. In this paper, we are concerned with 2-regular and 3-regular simple queues, for which the degree of each vertex is at most one and the arc lengths are at least 2 and 3, respectively. We show that 2-regular simple queues are in one-to-one correspondence with hill-free Motzkin paths, which have been enumerated by Barcucci, Pergola, Pinzani, and Rinaldi by using the Enumerating Combinatorial Objects method. We derive a recurrence relation for the generating function of Motzkin paths with $$k_i$$ peaks at level i, which reduces to the generating function for hill-free Motzkin paths. Moreover, we show that 3-regular simple queues are in one-to-one correspondence with Motzkin paths avoiding certain patterns. Then we obtain a formula for the generating function of 3-regular simple queues. Asymptotic formulas for 2-regular and 3-regular simple queues are derived based on the generating functions. [ABSTRACT FROM AUTHOR]

As a model of a service center with multiple servers and prioritized impatient customers served in reverse order of arrival such as the 9-1-1 call center in the United States, we study an M/M/ $$ m $$ nonpreemptive priority (last-come, first-served within the same class) queueing system with impatient customers in the steady state. We analyze the waiting time for those customers who are served successfully and the time to abandonment for those customers who leave the system while waiting. Explicit formulas are given for the probabilities of service and abandonment as well as the mean and second moment of the waiting time for customers of each class. Numerical examples are shown in order to demonstrate the computation of theoretical formulas. The difference in the behavior of the waiting time from that in the corresponding first-come, first-served system is discussed. [ABSTRACT FROM AUTHOR]

Due to intra-flow and inter-flow interference problems, the throughput performance decreases dramatically in a multi-hop wireless network. These two kinds of bandwidth unfair sharing problems could cause serious collisions and congestion, hence affecting the performance of multi-hop wireless networks. That is to say, data packets that need to traverse more hops to arrive at the destination will get lower throughput and result in the inter-flow fairness problem. Furthermore, the quality of video transmission is especially poor in traditional multi-hop wireless network environments. Therefore, in this paper, we propose a virtual queue management scheme that does not require the modification of any communication protocol. According to the number of flows, it adjusts the queue management scheme to achieve each flow's fair sharing of channel resource. It also improves the quality of video transmission. Through NS2 simulations, the results show that our proposed scheme can mitigate the inter-flow fairness problem and effectively improves the quality of video transmission. [ABSTRACT FROM AUTHOR]