In operation research this is one of the intresting area which having lot of applications to apply in our real life. it can be used for both the service and manufacturing industry.
This a project on generation of a FCFS , single server queuing theory model followed by stats to analyze the queue length, customer distribution etc. & various possible cases to improve
This a project on generation of a FCFS , single server queuing theory model followed by stats to analyze the queue length, customer distribution etc. & various possible cases to improve
Simulation of Queueing Systems(Single-Channel Queue).Badrul Alam
A grocery store has one checkout counter. Customer arrive at this counter at random from 1 to 8 minutes apart and each interval time has the same probability of occurrence. The service time vary from 1 to 6 minutes, with probability give below:
Queueing theory is the mathematical study of waiting lines, or queues. A queueing model is constructed so that queue lengths and waiting time can be predicted
Simulation of Queueing Systems(Single-Channel Queue).Badrul Alam
A grocery store has one checkout counter. Customer arrive at this counter at random from 1 to 8 minutes apart and each interval time has the same probability of occurrence. The service time vary from 1 to 6 minutes, with probability give below:
Queueing theory is the mathematical study of waiting lines, or queues. A queueing model is constructed so that queue lengths and waiting time can be predicted
Farmacia ni Dok is a Pharmacy Franchising Company that carries Branded and Generic Medicines, Natural Supplements, and Consumer Products in a convenient and friendly store setup, complemented with trustworthy and reliable customer service.
It offers a breakthrough Franchise Format -- the 2-in-1 Combo Business Package: Retail Pharmacy + Distribution Center!
Backed by Francorp -- the world’s leader in franchising (Retail Franchise Consultant) and GMB Franchise Developers (Distribution Franchise Consultant), Farmacia ni Dok boasts of strong Management Team and Corporate Partners with over 10 years expertise in the Pharmaceutical Operation and Distribution, Importation, and Manufacturing (adhere to the GMP or Good Manufacturing Practice to “ensure that their products are safe, pure, and effective!
CIM to Modelica Factory - Automated Equation-Based Cyber-Physical Power Syste...Luigi Vanfretti
The Common Information Model (CIM) is described using the Unified Modeling Language (UML). UML can also describe data model of cyber-physical power system components and networks. However, there are several difficulties to transform the data model into a strictly defined mathematical model. A strictly defined mathematical model is one for which all-differential algebraic and discrete model equations are explicitly defined [1] (i.e. the equations are written in human readable form). This is known as equation-based modelling [2], and it is utilized in many areas such as the automotive and aerospace industry [3].
The automated generation of an unambiguous equation-based model would allow performing time-domain simulations of cyber-physical power systems [4] and the assessment of textual requirements, which could be defined from the UML model directly [5]. This flexibility would allow adopting model-based systems engineering practices within the power industry, such as those used in process control.
For the implementation of models in an equation-based language, the Modelica language [6] is the one of the best choices because it follows the Object Oriented Programming (OOP) notation, with a close relation with UML. Furthermore, the ModelicaML [5], an extended subset of the OMG Unified Modeling Language, enables integrated modelling and simulation of system requirements and design. Combining CIM, ModelicaML and Modelica models of cyber-physical power system components it is possible to automatically generate unambiguous mathematical models that can be used for simulation and requirements verification [7].
This CIM to Modelica Factory talk explores this possibility.
One of the main challenges that we face with power systems models defined using the Modelica language is the initialization of the dynamic states (in equilibrium condition) of the components within a model [8, 9]. However, objects and components modelled in CIM standard contain attributes for storing a power flow solution.
The purpose of the work described in this presentation is to develop a software tool capable to transform a CIM object model into a Modelica model that can be directly simulated using different Modelica engines. To this aim, we start from the CIM/UML representation of power system components and models, and exploit the ModelicaML profile to achieve a proper code representation of the power system in Modelica code. To confront issues with dynamic initialization, the power flow solution from CIM is linked to the Modelica component models and utilized within the initialization algorithms of the simulation engines. The result is a software tool that allows performing time domain simulations directly from a CIM/UML structure, while maintaining consistency in the resulting mathematical model within different simulation engines.
Model Runway, Part 3 Design Best Practices at Blue Cross BlueShieldRoger Snook
This is part 3 from the series: https://www.ibm.com/developerworks/mydeveloperworks/blogs/669242b1-dd91-4d63-a08f-231314c793bb/entry/model_runway_see_the_latest_design_best_practices_at_bluecross_blueshield24?lang=en
Case Study on Practical Applications of Lean Principles - Phillip Cain, Alcon...marcus evans Network
Phillip Cain, Alcon Laboratories, Inc. - Speaker at the Spring 2012 Medical Manufacturing Summit held in Las Vegas, NV, delivered his presentation entitled Case Study on Practical Applications of Lean Principles
Where Is the Pharmaceutical Industry on Supply Chain Maturity? What Can They ...Lora Cecere
A presentation made on October 20th at the Integrichain Conference in Baltimore on the current state of the pharmaceutical industry and what industry leaders can learn from consumer products/retail collaboration.
This slide was prepared as a part of presentation in a course work of Master in IT, IIT, University of Dhaka. The main slide was prepared by Dr. Sam Labi of Purdue University and Dr. Fred of MIT.
MCM,MCA,MSc, MMM, MPhil, PhD (Computer Applications)
Working as Associate Professor at Zeal Education Society, Pune for MCA Progrmme.
Having 18 Years teaching experience
Georgia Tech: Performance Engineering - Queuing Theory and Predictive ModelingBrian Wilson
This is one lecture in a semester long course \'CS4803EPR\' I put together and taught at Georgia Tech, entitled "Enterprise Computing Performance Engineering"
----
Performance Engineering Overview - Part 2…
Queuing Theory Overview
Early life-cycle performance modeling
Simple Distributed System Model
Sequence Diagrams
Fuzzy Retrial Queues with Priority using DSW Algorithmijceronline
In this paper we study the priority queueing model under fuzzy environment.It optimize a fuzzy priority queueing model (preemptive priority, non-preemptive priority) in which arrival rate ,service rate,retrial rate are fuzzy numbers.Approximate method of Extension namely DSW (Dong, Shah and Wong) algorithm is used to define membership functions of the performance measures of priority queuing system . DSW algorithm is based on the cut representation of fuzzy sets in a standard interval analysis. Numerical example is also illustrated to check the validity of the model.
Event Management System Vb Net Project Report.pdfKamal Acharya
In present era, the scopes of information technology growing with a very fast .We do not see any are untouched from this industry. The scope of information technology has become wider includes: Business and industry. Household Business, Communication, Education, Entertainment, Science, Medicine, Engineering, Distance Learning, Weather Forecasting. Carrier Searching and so on.
My project named “Event Management System” is software that store and maintained all events coordinated in college. It also helpful to print related reports. My project will help to record the events coordinated by faculties with their Name, Event subject, date & details in an efficient & effective ways.
In my system we have to make a system by which a user can record all events coordinated by a particular faculty. In our proposed system some more featured are added which differs it from the existing system such as security.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
COLLEGE BUS MANAGEMENT SYSTEM PROJECT REPORT.pdfKamal Acharya
The College Bus Management system is completely developed by Visual Basic .NET Version. The application is connect with most secured database language MS SQL Server. The application is develop by using best combination of front-end and back-end languages. The application is totally design like flat user interface. This flat user interface is more attractive user interface in 2017. The application is gives more important to the system functionality. The application is to manage the student’s details, driver’s details, bus details, bus route details, bus fees details and more. The application has only one unit for admin. The admin can manage the entire application. The admin can login into the application by using username and password of the admin. The application is develop for big and small colleges. It is more user friendly for non-computer person. Even they can easily learn how to manage the application within hours. The application is more secure by the admin. The system will give an effective output for the VB.Net and SQL Server given as input to the system. The compiled java program given as input to the system, after scanning the program will generate different reports. The application generates the report for users. The admin can view and download the report of the data. The application deliver the excel format reports. Because, excel formatted reports is very easy to understand the income and expense of the college bus. This application is mainly develop for windows operating system users. In 2017, 73% of people enterprises are using windows operating system. So the application will easily install for all the windows operating system users. The application-developed size is very low. The application consumes very low space in disk. Therefore, the user can allocate very minimum local disk space for this application.
Vaccine management system project report documentation..pdfKamal Acharya
The Division of Vaccine and Immunization is facing increasing difficulty monitoring vaccines and other commodities distribution once they have been distributed from the national stores. With the introduction of new vaccines, more challenges have been anticipated with this additions posing serious threat to the already over strained vaccine supply chain system in Kenya.
Courier management system project report.pdfKamal Acharya
It is now-a-days very important for the people to send or receive articles like imported furniture, electronic items, gifts, business goods and the like. People depend vastly on different transport systems which mostly use the manual way of receiving and delivering the articles. There is no way to track the articles till they are received and there is no way to let the customer know what happened in transit, once he booked some articles. In such a situation, we need a system which completely computerizes the cargo activities including time to time tracking of the articles sent. This need is fulfilled by Courier Management System software which is online software for the cargo management people that enables them to receive the goods from a source and send them to a required destination and track their status from time to time.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
TECHNICAL TRAINING MANUAL GENERAL FAMILIARIZATION COURSEDuvanRamosGarzon1
AIRCRAFT GENERAL
The Single Aisle is the most advanced family aircraft in service today, with fly-by-wire flight controls.
The A318, A319, A320 and A321 are twin-engine subsonic medium range aircraft.
The family offers a choice of engines
Democratizing Fuzzing at Scale by Abhishek Aryaabh.arya
Presented at NUS: Fuzzing and Software Security Summer School 2024
This keynote talks about the democratization of fuzzing at scale, highlighting the collaboration between open source communities, academia, and industry to advance the field of fuzzing. It delves into the history of fuzzing, the development of scalable fuzzing platforms, and the empowerment of community-driven research. The talk will further discuss recent advancements leveraging AI/ML and offer insights into the future evolution of the fuzzing landscape.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
1. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
QUEUING ANALYIS
QUEUING ANALYSIS
ABINANTH M
Roll No: 15MF01
E-mail: abinanthsathya94@gmail.com
1
2. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Queuing theory definitions
• (Bose) “the basic phenomenon of queuing arises whenever a shared facility
needs to be accessed for service by a large number of jobs or customers.”
• (Wolff) “The primary tool for studying these problems [of congestions] is
known as queueing theory.”
• (Kleinrock) “We study the phenomena of standing, waiting, and serving, and
we call this study Queuing Theory." "Any system in which arrivals place
demands upon a finite capacity resource may be termed a queueing
system.”
• (Mathworld) “The study of the waiting times, lengths, and other properties of
queues.”
2
3. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
QUEUING THEORY
Queuing theory deals with modeling and analyzing systems with queues of items and
servers that process the items.
Queuing theory is the mathematics of waiting lines.
It is extremely useful in predicting and evaluating system performance.
Queuing theory has been used for operations research, manufacturing and systems
analysis.
Traditional queuing theory problems refer to customers visiting a store, analogous to
requests arriving at a device.
QUEUING ANALYIS
3
4. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
• Capacity problems are very common in industry and one of the main drivers of
process redesign
– Need to balance the cost of increased capacity against the gains of increased
productivity and service
• Queuing and waiting time analysis is particularly important in service systems
– Large costs of waiting and of lost sales due to waiting.
Why is Queuing Analysis Important?
QUEUING ANALYIS
4
5. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Applications of Queuing Theory
• Telecommunications
• Traffic control
• Determining the sequence of computer operations
• Predicting computer performance
• Health services (eg. control of hospital bed assignments)
• Airport traffic, airline ticket sales
• Layout of manufacturing systems.
5
6. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Queuing System Costs
QUEUING ANALYIS
6
Total expected cost = waiting time cost + cost of providing service
Cost
Minimum
Total
Cost
Low Level
Of Service
High Level
Of Service
Optimal Service
Level
Cost of Waiting
Time
( time x value of time )
Cost of Providing
Service
( salaries + benefits )
Total Cost
7. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Waiting and Idle time costs
Cost of waiting customers Cost of idle service facility
• Indirect cost of business loss
• Direct cost of idle equipment or
person.
• Payment to be made to the
servers(engaged at the
facilities),for the period for
which they remain idle.
The optimum balance of costs can be made by scheduling the flow of units
or providing proper number of service facilities .
7
Courtesy : Google images/ sleeping
8. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Characteristics of a Queuing System
The queuing system is determined by:
• Arrival characteristics
• Queue characteristics
– Queue length (max possible queue length) – either limited or unlimited
– Service discipline – usually FIFO (First In First Out)
• Service facility characteristics
QUEUING ANALYIS
8
Courtesy: opnet ppt
9. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Arrival Characteristics
• Size of the arrival population – either infinite or limited
• Arrival distribution:
– Either fixed or random
– Either measured by time between consecutive arrivals, or arrival rate
– The Poisson distribution is often used for random arrivals
Poisson Distribution
• Average arrival rate is known
• Average arrival rate is constant for some number of time periods
• Number of arrivals in each time period is independent
QUEUING ANALYIS
9
probability
Arrival per unit time(λ)
10. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Poisson Distribution
λ = the average arrival rate per time unit
P(x) = the probability of exactly x arrivals occurring during one time period
Where : P ( X ) = probability of X arrivals
X = number of arrivals per time unit
λ = the average arrival rate
e = 2.7183 ( base of the natural logarithm )
Example:
If the average arrival rate per hour is two people ( λ = 2 ) , what is the probability of three (3)
arrivals per hour?
= 0.1804 ≈ 18 %
QUEUING ANALYIS
10
11. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Little’s Law
• Very simple law that works from a Case Western Reserve University professor Dr. Little
• For a given arrival rate, the time in the system is proportional to average time spent in the
system
N = T
where
N: average no. of customers in the system
: Customer arrival rate (per unit time)
T: average time in the system per customer (response time)
Example:
Server satisfies input request in average of 100 msec. Input rate is about 100 requests/sec.
What is the mean number of requests at the server?
Mean number at server = arrival rate x response time
= (100 requests/sec) x (0.1 sec)
= 10 requests
QUEUING ANALYIS
11
12. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Service Facility Characteristics
1. Configuration of service facility
• Number of servers (or channels)
• Number of phases (or service stops)
2. Service distribution
• The time it takes to serve 1 arrival
• Can be fixed or random
• Exponential distribution is often used.
Exponential Distribution
μ = average service time
t = the length of service time (t > 0)
P(t) = probability that service time will be greater than t
P(t) = e- μt
QUEUING ANALYIS
.25
.20
.15
.10
.05
.00
P
R
O
B
A
B
I
L
I
T
Y
0 30 60 90 120 150 180 210
seconds
THE PROBABILITY
A CUSTOMER
WILL REQUIRE
THAT SERVICE
TIME
12
13. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Behavior of Arrivals
Most queuing formulas assume that all arrivals stay until service is completed
Balking refers to customers who do not join the queue
Reneging refers to customers who join the queue but give up and leave before completing
service
Jockeying- When a customer shifts from one queue to another.
Jockeying can be discouraged by placing
barricades such as magazine racks and
impulse item displays between waiting lines
Queue Discipline
QUEUING ANALYIS
13
14. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Queuing Theory Variables
• Lambda ( λ ) is the average arrival rate of people or items into the service system. It can
be expressed in seconds, minutes, hours, or days.
• Mu ( μ ) is the average service rate of the service system. It can be expressed as the
number of people or items processed per second, minute, hour, or day.
• Rho ( ρ ) is the % of time that the service facility is busy on the average. It is also known
as the utilization rate.
• Mu ( M ) is a channel or service point in the service system. Examples are gasoline
pumps, checkout counters, vending machines, bank teller windows.
• Phases are the number of service points that must be negotiated by a customer or item
before leaving the service system.
QUEUING ANALYIS
14
15. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Measuring Queue Performance
• Pn is the probability of exactly n customers in system
• Po or ( 1 – ρ ) is the percentage of time that the service facility is idle.
• L is the average number of people or items in the service system both waiting to be served and currently
being served.
• Lq is the average number of people or items in the waiting line ( queue ) only !
• W is the average time a customer or item spends in the service system, both waiting and receiving
service.
• Wq is the average time a customer or item spends in the waiting line ( queue ) only.
• Pw is the probability that a customer or item must wait to be served.
QUEUING ANALYIS
15
16. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Kendall Notation 1/2/3(/4/5/6)
Six parameters are
• First three typically used, unless specified
1. Arrival Distribution
(M for Poisson, D for deterministic, and G for general)
2.. Service Distribution
(M for Poisson, D for deterministic, and G for general)
3. Number of servers (PARALLEL SERVICE)
4. Total Capacity (infinite if not specified) [max no. of customers]
5. Population Size (infinite)
6. Service Discipline (FCFS/FIFO)
QUEUING ANALYIS
16
17. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Models with example
Name
(Kendall Notation)
Example
Simple system
(M / M / 1)
Customer service desk in a store
Multiple server
(M / M / s)
Airline ticket counter
Constant service
(M / D / 1)
Automated car wash
General service
(M / G / 1)
Auto repair shop
Limited population
(M / M / s / ∞ / N)
An operation with only 12 machines that might break
QUEUING ANALYIS
17
18. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Single Server Queuing System (M/M/1)
Queue
Arrivals
λ= arrival rate
server
Dispatching
discipline
w = mean # items waiting
Tw = mean waiting time
Departures
Ts = mean service time
ρ = utilization
R mean # items residing in the system
Tr = mean residence time
QUEUING ANALYIS
EXIT
18
19. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Service Channels
• Single channel queuing system
• Multi channel queuing system
• Single channel multi phase system
• Multi channel multi phase system
17
20. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Situation
– Patients arrive according to a Poisson process with intensity ( the time
between arrivals is exp() distributed.
– The service time (the doctor’s examination and treatment time of a patient)
follows an exponential distribution with mean 1/ (=exp() distributed)
The Emergency can be modeled as an M/M/c system where,
c=the number of doctors
Data gathering
= 2 patients per hour
= 3 patients per hour
Example Hospital
QUEUING ANALYIS
20
21. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Operating Characteristics for M/M/1 Queue
1. Average server utilization
2. Average number of customers waiting
3. Average number in system
4. Average waiting time
5. Average time in the system
6. Probability of 0 customers in system
7. Probability of exactly n customers in system Pn = (λ/μ )n P0
QUEUING ANALYIS
21
22. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
• Interpretation
– To be in the queue = to be in the waiting room
– To be in the system = to be in the Emergency (waiting or under treatment)
Summary of Results – Government Hospital
Characteristic One doctor (c=1) Two Doctors (c=2)
2/3 1/3
P0 1/3 1/2
(1-P0) 2/3 1/2
P1 2/9 1/3
Lq 4/3 patients 1/12 patients
L 2 patients 3/4 patients
Wq 2/3 h = 40 minutes 1/24 h = 2.5 minutes
W 1 h 3/8 h = 22.5 minutes
QUEUING ANALYIS
22
23. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
M/M/1 Example I
Traffic to a message switching center for one of the outgoing communication lines arrive in a
random pattern at an average rate of 240 messages per minute. The line has a transmission
rate of 800 char/ second. The message length distribution (including control characters) is
approximately exponential with an average length of 176 characters. Calculate the following
principal statistical measures of system performance, assuming that a very large number of
message buffers are provided:
(a) Average number of messages in the system
(b) Average number of messages in the queue waiting to be transmitted.
(c) Average time a message spends in the system.
(d) Average time a message waits for transmission
(e) Probability that 10 or more messages are waiting to be transmitted.
(f) 90th percentile waiting time in queue.
QUEUING ANALYIS
23
24. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
M/M/1 Example I (cont.)
Performance E[s] = Average Message Length / Line Speed
= {176 char/message} / {800 char/sec}
= 0.22 sec/message
Average service rate = 1 / 0.22 {message / sec}
= 4.55 message / sec
Average arrival rate = 240 message / min
= 4 message / sec
% of time service busy = E[s] = /
= 0.88
QUEUING ANALYIS
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25. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
M/M/1 Example I (cont.)
(a) Average number of messages in the system L = / (1 - )
= 7.33 (messages)
(b) Average number of messages in the queue waiting to be transmitted Lq= 2 / (1 - )
= 6.45 (messages)
(c) Average time a message spends in the system. W = E[s] / (1 - )
= 1.83 (sec)
(d) Average time a message waits for transmission Wq = × E[s] / (1 - )
= 1.61 (sec)
(e) Probability that 10 or more messages are waiting to be transmitted.
P [11 or more messages in the system] = 11 = 0.245
(f) 90th percentile waiting time in queue pq(90) = W ln{(100-90) }
= W ln(10)
= 3.98 (sec)
QUEUING ANALYIS
25
26. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Therefore:
μ = 30
λ = 20
M = 1
Single-Channel / Single-Phase Model
• A clerk can serve thirty customers per
hour on average.
• Twenty customers arrive each hour on
average.
APPLICATION - 2
26
QUEUING ANALYIS
27. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
M/M/1 queue model
27
1
Wq
W
L
Lq
28. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
The Average Number of Customers in the System
The Average Number Just Waiting in Line
The Average Customer Time Spent in the System
The Percentage of Time the System is Busy
Single-Channel / Single-Phase Model
28
QUEUING ANALYIS
29. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Software packages
General
• RESQ
• QNA
• PANCEA
Manufacturing applications
• CAN-Q
• MANUPLAN
• MVAQ
29
30. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM 30
QUEUING ANALYIS
31. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM 31
QUEUING ANALYIS
32. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM 32
QUEUING ANALYIS
33. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Multi-server /single queue
Queue
Arrivals
λ= arrival rate
Dispatching
discipline
server0
server1
Server n
…..
QUEUING ANALYIS
33
35. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Multi-Channel Single-Phase Systems
This system is a single waiting line serviced by more than one server.
It assumes:
an infinite calling population
a first-come, first-served queue discipline
a Poisson arrival rate
negative exponential service times
Additional Parameters
M = number of servers or channels
Mμ = mean effective service rate for the facility
QUEUING ANALYIS
35
36. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Multi-Channel Single-Phase Systems
Application Example
A bank has three loan officers on duty, each of whom can serve four customers
per hour. Every hour, ten loan applicants arrive at the loan department and join a
common queue. What are the system’s operating characteristics?
= .045 = 4.5%
The probability that the service facility is idle:
QUEUING ANALYIS
36
37. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Application Example Continued
L = 3.515625 + 2.5 ≈ 6.0
The average number of customers in the system:
QUEUING ANALYIS
37
38. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Lq = 6 – [10/4] = 3.5
W = 6/10 = .60 hours ( 36 minutes )
Wq = 3.5 / 10 = .35 hours ( 21 minutes )
L = 6
The average number of customers in the queue:
The average time a customer spends in the system:
The average waiting time in the queue:
The probability that all the system’s servers are currently busy:
or
Application Example Continued
QUEUING ANALYIS
38
39. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Finite Calling Population Model
Application
A shop has fifteen (15) machines which are repaired in the same order in which they fail. The
machines fail according to a Poisson distribution, and the service times are exponentially
distributed. One (1) mechanic is on-duty. A machine fails on average,
every forty (40) hours. The average repair takes 3.6 hours.
N = 15 machines
λ = 1/40th of a machine per hour = .0250 machine per hour
μ = 1/3.6th of a machine per hour = .2778 machine per hour
39
QUEUING ANALYIS
40. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Finite Calling Population Model
N = size of the finite calling population
Probability that the system is empty:
Average length of the queue
= 6.16%
40
QUEUING ANALYIS
41. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Average number of customers (items) in the system:
L = Lq + ( 1 – Po ) = 3.63 + ( 1 - .0616 ) = 4.57 machines
Average waiting time in the queue:
( N – L ) λ
Lq
Average time in the system:
W = Wq + ( 1 / μ ) = 13.94 + ( 1 / .2778 ) = 17.54 hours
Wq = = 13.94 hours
Finite Calling Population Model
41
QUEUING ANALYIS
42. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Priority Servers
• Packets form priority classes (each may have several flows)
• There is a separate FIFO queue for each priority class
• Packets of lower priority start transmission only if no higher priority packet
is waiting
• Priority types:
– Non-preemptive (high priority packet must wait for a lower priority packet
found under transmission upon arrival)
– Preemptive (high priority packet does not have to wait …)
Courtesy: http://www.athenasc.com/probbook.html
42
43. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Priority Queuing
• Packets are classified into separate queues
– E.g., based on source/destination IP address, source/destination TCP port, etc.
• All packets in a higher priority queue are served before a lower priority
queue is served
– Typically in routers, if a higher priority packet arrives while a lower priority
packet is being transmitted, it waits until the lower priority packet completes
Courtesy: http://www.athenasc.com/probbook.html
43
44. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Behavioral Considerations
• Customer willingness to wait depends on what is perceived as reasonable.
• Waiting lines that are always moving are perceived as less painful.
• Customer willingness to wait is higher if they know that others are also waiting their turn.
• Customers should be permitted to perform the services that they can easily provide for
themselves
• Well projected waiting times allow customers to adjust their expectations and therefore
their aggravation.
• If customers are kept busy, their waiting time may not be construed as wasted time
QUEUING THEORY
44
QUEUING ANALYIS
Courtesy : google images/ queue
45. COURSE CODE. PAGE
FLEXIBLE MANUFACTURING SYSTEM
Department of Mechanical EngineeringFaculty: VIJAYANAND.V
10-Feb-17 15MN24
CLASS.
ME: IE & CIM
Suggestions for Managing Queues
1. Determine an acceptable waiting time for your customers
2. Try to divert your customer’s attention when waiting
3. Inform your customers of what to expect
4. Keep employees not serving the customers out of sight
5. Segment customers
6. Train your servers to be friendly
7. Encourage customers to come during the slack periods
8. Take a long-term perspective toward getting rid of the queues
45