Mathematical Analysis of Queue with Phase Service: An Overview

We discuss various aspects of phase service queueing models. A large number of models have been developed in the area of queueing theory incorporating the concept of phase service. These phase service queueing models have been investigated for resolving the congestion problems of many day-to-day as well as industrial scenarios. In this survey paper, an attempt has been made to review the work done by the prominent researchers on the phase service queues and their applications in several realistic queueing situations. The methodology used by several researchers for solving various phase service queueing models has also been described. We have classified the related literature based on modeling and methodological concepts. The main objective of present paper is to provide relevant information to the system analysts, managers, and industry people who are interested in using queueing theory to model congestion problems wherein the phase type services are prevalent

Analysis of M[X1],M[X2]/G1,G2/1 retrial queueing system with priority services, working breakdown, collision, Bernoulli vacation, immediate feedback, starting failure and repair

This paper considers an M[X1] , M[X2] /G1,G2/1 general retrial queueing system with priority services. Two types of customers from different classes arrive at the system in different independent compound Poisson processes. The server follows the non-pre-emptive priority rule subject to working breakdown, Bernoulli vacation, starting failure, immediate feedback, collision and repair. After completing each service, the server may go for a vacation or remain idle in the system. The priority customers who find the server busy are queued in the system. If a low-priority customer finds the server busy, he is routed to orbit that attempts to get the service. The system may become defective at any point of time while in operation. However, when the system becomes defective, instead of stopping service completely, the service is continued to the interrupted customer only at a slower rate. Using the supplementary variable technique, the joint distribution of the server state and the number of customers in the queue are derived. Finally, some performance measures are obtained

Unreliable Server Retrial Queue with Optional Service and Multi-Phase Repair

In this paper, the retrial unreliable server queue with batch arrivals is considered. The arrival rates of the units are different and dependent upon the joining probabilities according to the server status. On arrival, if unit finds the busy server, he may retry for the service after a random duration of time. The server facilitates the essential service and optional service, if opted after essential service. Moreover, the server is unreliable and subject to the breakdown while rendering essential/optional service. The failed server may immediately undergo for the compulsory multiphase repair or may wait to start the repair due to any technical reasons. The server can also avail the optional vacation under the Bernoulli schedule after finish the service of each unit or may continue to serve the next unit. The variables corresponding to elapsed times of general distributed service process, retrial process, repair process and vacation duration, as supplementary variables and used to frame the governing equations. By using the probability generating functions of joint distributions of the units at different states of the server, the performance characteristics of the system are derived. To validate the results, the sensitivity analysis has been performed by taking the numerical illustration

A Non-Markovian Multistage Batch Arrival Queue with Breakdown and Reneging

The present investigation deals with analysis of non-Markovian queueing model with multistage of services. When the server is unavailable during the system breakdown (or) vacation periods, we consider reneging to prevail. Supplementary variable techniques have been adopted to obtain steady state system length distributions. The numerical illustrations are provided to validate the tractability of performance measures as far as computational aspect is concerned. Numerical results in the form of graphical representation are also presented. Practical large scale industry applications are described to justify our model

The Whitworthian 2009-2010

The Whitworthian student newspaper, September 2009-May 2010.https://digitalcommons.whitworth.edu/whitworthian/1094/thumbnail.jp

Toward a Global Human Rights Regime for Temporary Migrant Workers: Lessons from the Case of Filipino Workers in the United Arab Emirates

Temporary contract migrants as a class fall between systems of responsibility: home country, host country, and international community. The systems are separately inadequate and basically uncoordinated, leaving migrants in a precarious situation. The situation of temporary contract migrants is even more precarious as they cross international borders without a path to citizenship or full enfranchisement in the political, economic, and social life of the host country. Where citizenship and residence/employment are divided between multiple countries, the corresponding human rights obligations are similarly divided. This division results in migrant rights falling between different state-based systems of responsibility. Human rights can be divided between those that are inherent in citizenship (citizenship obligation) which are the responsibility of the sending state, those that are inherent in the physical body (presence obligation) which are the responsibility of the receiving state, and those that fall between systems of responsibility (involvement obligation) which require sending and receiving countries to act cooperatively. These categories provide clear guidance in sorting out responsibilities for the rights of temporary contract migrants and direct us towards possible avenues for reform. Once adopted, this framework can help guide bilateral or regional agreements on a case-by-case basis. Although the principles underlying split responsibility are universal, the required elements of cooperation are likely to vary between different contexts. This dissertation draws on analyses and interviews conducted with Filipino temporary contract migrants in the United Arab Emirates in order to substantiate the argument, illustrating strategies that migrants as agents utilize to improve their conditions, the tradeoffs that they have made in order to secure their livelihood in a global job market, and the impact that current policy frameworks have on their lived experience

Fuelling the zero-emissions road freight of the future: routing of mobile fuellers

The future of zero-emissions road freight is closely tied to the sufficient availability of new and clean fuel options such as electricity and Hydrogen. In goods distribution using Electric Commercial Vehicles (ECVs) and Hydrogen Fuel Cell Vehicles (HFCVs) a major challenge in the transition period would pertain to their limited autonomy and scarce and unevenly distributed refuelling stations. One viable solution to facilitate and speed up the adoption of ECVs/HFCVs by logistics, however, is to get the fuel to the point where it is needed (instead of diverting the route of delivery vehicles to refuelling stations) using "Mobile Fuellers (MFs)". These are mobile battery swapping/recharging vans or mobile Hydrogen fuellers that can travel to a running ECV/HFCV to provide the fuel they require to complete their delivery routes at a rendezvous time and space. In this presentation, new vehicle routing models will be presented for a third party company that provides MF services. In the proposed problem variant, the MF provider company receives routing plans of multiple customer companies and has to design routes for a fleet of capacitated MFs that have to synchronise their routes with the running vehicles to deliver the required amount of fuel on-the-fly. This presentation will discuss and compare several mathematical models based on different business models and collaborative logistics scenarios

Accountants\u27 index. Twenty-fourth supplement, January-December 1975

https://egrove.olemiss.edu/aicpa_accind/1026/thumbnail.jp

Bowdoin Orient v.126, no.1-23 (1997-1998)

https://digitalcommons.bowdoin.edu/bowdoinorient-1990s/1010/thumbnail.jp