Open Access. Powered by Scholars. Published by Universities.®

Operations Research, Systems Engineering and Industrial Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 18 of 18

Full-Text Articles in Operations Research, Systems Engineering and Industrial Engineering

Efficient Redundancy Techniques In Cloud And Desktop Grid Systems Using Map/G/C-Type Queues, Srinivas R. Chakravarthy, Alexander Rumyantsev Mar 2018

Efficient Redundancy Techniques In Cloud And Desktop Grid Systems Using Map/G/C-Type Queues, Srinivas R. Chakravarthy, Alexander Rumyantsev

Industrial & Manufacturing Engineering Publications

Cloud computing is continuing to prove its flexibility and versatility in helping industries and businesses as well as academia as a way of providing needed computing capacity. As an important alternative to cloud computing, desktop grids allow to utilize the idle computer resources of an enterprise/community by means of distributed computing system, providing a more secure and controllable environment with lower operational expenses. Further, both cloud computing and desktop grids are meant to optimize limited resources and at the same time to decrease the expected latency for users. The crucial parameter for optimization both in cloud computing and in ...


Optimizing Production Schedule With Energy Consumption And Demand Charges In Parallel Machine Setting, Farnaz Ghazi Nezami, Mojtaba Heydar, Regina Berretta Dec 2017

Optimizing Production Schedule With Energy Consumption And Demand Charges In Parallel Machine Setting, Farnaz Ghazi Nezami, Mojtaba Heydar, Regina Berretta

Industrial & Manufacturing Engineering Presentations And Conference Materials

Environmental sustainability concerns, along with the growing need for electricity and associated costs, make energy-cost reduction an inevitable decision-making criterion in production scheduling. In this research, we study the problem of production scheduling on nonidentical parallel machines with machine-dependent processing times and known job release dates to minimize total completion time and energy costs. The energy costs in this study include demand and consumption charges. We present a mixed-integer nonlinear model to formulate the problem. The model is then linearized and its performance is tested through numerical experiments.


Split-Merge Model Of Workunit Replication In Distributed Computing, Alexander Rumyantsev, Srinivas R. Chakravarthy Aug 2017

Split-Merge Model Of Workunit Replication In Distributed Computing, Alexander Rumyantsev, Srinivas R. Chakravarthy

Industrial & Manufacturing Engineering Presentations And Conference Materials

No abstract provided.


Comparing Three Instructional Modes For An Engineering Economy Course, Farnaz Ghazi Nezami, M. B. Yildirim, G. Grossi Crema Dec 2016

Comparing Three Instructional Modes For An Engineering Economy Course, Farnaz Ghazi Nezami, M. B. Yildirim, G. Grossi Crema

Industrial & Manufacturing Engineering Publications

This study compares three instructional modes in an “Engineering Economy” course: online, face-to-face (FtF), and flipped. Engineering Economy is a core course in this study and incorporates students with diverse backgrounds from different engineering majors. To discern the relation between student characteristics and teaching modality, an online questionnaire was designed for each mode and distributed over a two-year period. Data was collected and several statistical analyses were conducted to study the relationship between pedagogical delivery modes and various student-based factors such as gender, age, course load, living distance from campus, computer skills, work status, and first language. Students’ performance, persistence ...


Map/Ph/1 Queueing Model With Working Vacation And Crowdsourcing, Srinivas R. Chakravarthy, Serife Ozkar Sep 2016

Map/Ph/1 Queueing Model With Working Vacation And Crowdsourcing, Srinivas R. Chakravarthy, Serife Ozkar

Industrial & Manufacturing Engineering Publications

Crowdsourcing has been used in different domains such as healthcare, computer science, environmental sciences, business and marketing. However, only recently, queueing models useful in the context of crowdsourcing have been studied. These studies involve queueing models of the type M/M/c, MAP/PH/1, and MAP/PH/c. In this paper we introduce vacation and working vacation in the context of MAP/PH/1 with crowdsourcing and highlight the qualitative aspects of the model through illustrative examples.


Developing Entrepreneurial Mindset In Industrial Engineering Classes: A Case Study, Farnaz Ghazi Nezami, Massoud Tavakoli, Mohammad Torfeh Jun 2016

Developing Entrepreneurial Mindset In Industrial Engineering Classes: A Case Study, Farnaz Ghazi Nezami, Massoud Tavakoli, Mohammad Torfeh

Industrial & Manufacturing Engineering Presentations And Conference Materials

Instilling entrepreneurial mindset among engineering students is one of the challenges in engineering education. This paper presents the efforts to improve a core undergraduate industrial engineering course, Designing Value in Supply Chain, to infuse entrepreneurial thinking among students using an internally funded grant by Kern Entrepreneurial Engineering Network (KEEN). For this purpose, three new course modules are designed and their effectiveness on student learning is evaluated. This course is ideal for establishing entrepreneurially minded learning (EML) as a systematic approach is required for managing the chain of supply, especially since the impacts of the decisions are not isolated and will ...


Active Learning In Supply Chain Management Course, Farnaz Ghazi-Nezami, Mehmet Bayram Yildirim Jun 2015

Active Learning In Supply Chain Management Course, Farnaz Ghazi-Nezami, Mehmet Bayram Yildirim

Industrial & Manufacturing Engineering Presentations And Conference Materials

Active Learning in the Supply Chain Management Course. This paper presents a new active learning approach implemented in the Supply ChainManagement (SCM) course in the Industrial and Manufacturing Engineering Department.Previously, in this course the fundamentals of supply chain and logistics, drivers of supply chainperformance and analytical tools necessary to develop solutions for a variety of SCM and designproblems were mainly covered through class lectures and case study discussions. In the past fewyears, due to the growth in the needs of the organizations to “Lean” principles, the course wasmodified to satisfy this requirement more efficiently. For this purpose a new ...


Preemptive Resume Priority Call Center Model With Two Classes Of Map Arrivals, Srinivas R. Chakravarthy, M. Senthil Kumar, R. Arumuganathan Jan 2013

Preemptive Resume Priority Call Center Model With Two Classes Of Map Arrivals, Srinivas R. Chakravarthy, M. Senthil Kumar, R. Arumuganathan

Industrial & Manufacturing Engineering Publications

Generally in call centers, voice calls (say Type 1 calls) are given higher priority over e-mails (say Type 2 calls). An arriving Type 1 call has a preemptive priority over a Type 2 call in service, if any, and the preempted Type 2 call enters into a retrial buffer (of finite capacity). Any arriving call not able to get into service immediately will enter into the pool of repeated calls provided the buffer is not full; otherwise, the call is considered lost. The calls in the retrial pool are treated alike (like Type 1) and compete for service after a ...


Analysis Of A Multi-Server Queueing Model With Vacations And Optional Secondary Services, Srinivas R. Chakravarthy Jan 2013

Analysis Of A Multi-Server Queueing Model With Vacations And Optional Secondary Services, Srinivas R. Chakravarthy

Industrial & Manufacturing Engineering Publications

In this paper we study a multi-server queueing model in which the customer arrive according to a Markovian arrival process. The customers may require, with a certain probability, an optional secondary service upon completion of a primary service. The secondary services are offered (in batches of varying size) when any of the following conditions holds good: (a) upon completion of a service a free server finds no primary customer waiting in the queue and there is at least one secondary customer (including possibly the primary customer becoming a secondary customer) waiting for service; (b) upon completion of a primary service ...


Analysis Of A K-Out-Of-N System With Spares, Repairs, And A Probabilistic Rule, Srinivas R. Chakravarthy Sep 2006

Analysis Of A K-Out-Of-N System With Spares, Repairs, And A Probabilistic Rule, Srinivas R. Chakravarthy

Industrial & Manufacturing Engineering Publications

We consider a k-out-of-N reliability system with identical components having exponential lifetimes. There is a single repairman who attends to failed components on a first comefirst-served basis. The repair times are assumed to be of phase type. The system has K spares that can be used according to a probabilistic rule to extend the lifetime of the system. The system is analyzed using Markov chain theory and some interesting results are obtained. A few illustrative numerical examples are discussed.


Algorithmic Analysis Of The Maximum Level Length In General-Block Two-Dimensional Markov Processes, Jesus R. Artalejo, Srinivas R. Chakravarthy Jun 2005

Algorithmic Analysis Of The Maximum Level Length In General-Block Two-Dimensional Markov Processes, Jesus R. Artalejo, Srinivas R. Chakravarthy

Industrial & Manufacturing Engineering Publications

Two-dimensional continuous-time Markov chains (CTMCs) are useful tools for studying stochastic models such as queueing, inventory, and production systems. Of particular interest in this paper is the distribution of the maximal level visited in a busy period because this descriptor provides an excellent measure of the system congestion. We present an algorithmic analysis for the computation of its distribution which is valid for Markov chains with general-block structure. For a multiserver batch arrival queue with retrials and negative arrivals, we exploit the underlying internal block structure and present numerical examples that reveal some interesting facts of the system.


A Multi-Server Markovian Queueing Model With Primary And Secondary Services, Valentina Klimenok, Srinivas R. Chakravarthy, Alexander Dudin Jan 2005

A Multi-Server Markovian Queueing Model With Primary And Secondary Services, Valentina Klimenok, Srinivas R. Chakravarthy, Alexander Dudin

Industrial & Manufacturing Engineering Presentations And Conference Materials

We study a multi-server queueing model in which the arrivals occur according to a Markovian arrival process. An arriving customer either (a) is lost due to all main servers being busy; or (b) enters into service with one of the main servers and leaves the system (as a satisfied primary customer); (c) enters into a service with one of the main servers, gets service in self-service mode, and is impatient to get a final service with one of the main servers, may leave the system (as a dissatisfied secondary customer); or (d) enters into service with one of the main ...


How To Increase The Ability Of A Student To Learn, Srinivas R. Chakravarthy Jun 2004

How To Increase The Ability Of A Student To Learn, Srinivas R. Chakravarthy

Industrial & Manufacturing Engineering Presentations And Conference Materials

An instructor is always challenged when covering the materials in a course (according to the syllabus) and at the same time making sure that all students have the opportunity to learn and understand the materials presented in the classroom. In this paper we will present some ideas and tools that enable one to try to achieve a balance. These are based on the author’s experience and perspective in teaching deterministic and stochastic operations research courses.


Multi-Threshold Control Of The Bmap/Sm/1/K Queue With Group Services, Alexander Dudin N., Srinivas R. Chakravarthy Mar 2003

Multi-Threshold Control Of The Bmap/Sm/1/K Queue With Group Services, Alexander Dudin N., Srinivas R. Chakravarthy

Industrial & Manufacturing Engineering Publications

We consider a finite capacity queue in which arrivals occur according to a batch Markovian arrival process (BMAP). The customers are served in groups of varying sizes. The services are governed by a controlled semi-Markovian process according to a multithreshold strategy. We perform the steady-state analysis of this model by computing (a) the queue length distributions at departure and arbitrary epochs, (b) the Laplace-Stieltjes transform of the sojourn time distribution of an admitted customer, and (c) some selected system performance measures. An optimization problem of interest is presented and some numerical examples are illustrated.


A K-Out-Of-N Reliability System With An Unreliable Server And Phase Type Repairs And Services: The (N, T) Policy, Srinivas R. Chakravarthy, Achyutha Krishnamoorthy, P. V. Ushakumari Jan 2001

A K-Out-Of-N Reliability System With An Unreliable Server And Phase Type Repairs And Services: The (N, T) Policy, Srinivas R. Chakravarthy, Achyutha Krishnamoorthy, P. V. Ushakumari

Industrial & Manufacturing Engineering Publications

In this paper we study a k-out-of-n reliability system in which a single unreliable server maintains n identical components. The reliability system is studied under the (N,T) policy. An idle server takes a vacation for a random amount of time T and then attends to any failed component waiting in line upon completion of the vacation. The vacationing server is recalled instantaneously upon the failure of the Nth component. The failure times of the components are assumed to follow an exponential distribution. The server is subject to failure with failure times exponentially distributed. Repair times of the component, fixing ...


Two Parallel Finite Queues With Simultaneous Services And Markovian Arrivals, Srinivas R. Chakravarthy, S. Thiagarajan Jan 1997

Two Parallel Finite Queues With Simultaneous Services And Markovian Arrivals, Srinivas R. Chakravarthy, S. Thiagarajan

Industrial & Manufacturing Engineering Publications

In this paper, we consider a finite capacity single server queueing model with two buffers, A and B, of sizes K and N respectively. Messages arrive one at a time according to a Markovian arrival process. Messages that arrive at buffer A are of a different type from the messages that arrive at buffer B. Messages are processed according to the following rules: 1. When buffer A(B) has a message and buffer B(A) is empty, then one message from A(B) is processed by the server. 2. When both buffers, A and B, have messages, then two messages ...


A Discrete Single Server Queue With Markovian Arrivals And Phase Type Group Services, Attahiru Sule Alfa, K. Laurie Dolhun, Srinivas R. Chakravarthy Mar 1995

A Discrete Single Server Queue With Markovian Arrivals And Phase Type Group Services, Attahiru Sule Alfa, K. Laurie Dolhun, Srinivas R. Chakravarthy

Industrial & Manufacturing Engineering Publications

We consider a single-server discrete queueing system in which arrivals occur according to a Markovian arrival process. Service is provided in groups of size no more than M customers. The service times are assumed to follow a discrete phase type distribution, whose representation may depend on the group size. Under a probabilistic service rule, which depends on the number of customers waiting in the queue, this system is studied as a Markov process. This type of queueing system is encountered in the operations of an automatic storage retrieval system. The steady-state probability vector is shown to be of (modified) matrix-geometric ...


A Finite Capacity Queue With Markovian Arrivals And Two Servers With Group Services, Srinivas Chakravarthy, Attahiru S. Alfa Feb 1994

A Finite Capacity Queue With Markovian Arrivals And Two Servers With Group Services, Srinivas Chakravarthy, Attahiru S. Alfa

Industrial & Manufacturing Engineering Publications

In this paper we consider a finite capacity queuing system in which arrivals are governed by a Markovian arrival process. The system is attended by two exponential servers, who offer services in groups of varying sizes. The service rates may depend on the number of customers in service. Using Markov theory, we study this finite capacity queuing model in detail by obtaining numerically stable expressions for (a) the steady-state queue length densities at arrivals and at arbitrary time points; (b) the Laplace-Stieltjes transform of the stationary waiting time distribution of an admitted customer at points of arrivals. The stationary waiting ...