outline introduction problem definition system dynamics basics cdeep : current state of the art...
TRANSCRIPT
OutlineIntroductionProblem DefinitionSystem Dynamics BasicsCDEEP : Current State of the artCDEEP ModelFeatures of a System Dynamics ModelConclusion & Future WorkReferences
IntroductionIndia produced 401,791 engineers in 2003-04
and in 2004-05, the number of engineering graduates increased to 464,743 [1].
But only 25 per cent of them are employable[1].
Main Reason : lack of well qualified teachersPossible Solution :
Make IIT education accessible through Distance Education Cost Effective Global Reach
Introduction continued …IITB has been running the distance education
program since last 10 years. Currently in the form of CDEEP to provide:
Good quality courses taught by IIT Bombay faculty
To everyone At any place
Both synchronous and asynchronous modesBut number of students benefiting from CDEEP
live courses has not increased as expected
Problem DefinitionTo model and analyse CDEEP system To find out :
If there is any bottleneck resourceWhat–If analysisIf any policy changes needed
using System Dynamics Why???
System Dynamics BasicsComputer simulation modeling for studying
and managing complex feedback systems, such as business, engineering, and social systems
Think in terms of cause-and-effect Focus on Feedback Loops
situation when output from an event will influence the same event in the future
StudyGrade
s
Parents’ Expectation
s
More More
More
SD Modeling: Standard approach [2] Identify the problemDevelop a dynamic hypothesisCreate a basic causal loop diagram Convert the causal diagram to a Stock flow
diagram Write the equationsEstimate the parameters and initial conditions.
using statistical methods, expert opinion, market research data or other relevant sources.
Simulate the model and analyze results
Causal Loop Diagramshows how one variable affects another. nodes represent variables and arrows (called
causal links) represent relationshipdifficult to infer the behavior of a system only
from its casual-loop representation
+ Feedback Loop
Node
Causal Link
timeP
op
ula
tio
n
Stock and Flow DiagramDistinguishes between different types of
variablesConsists of three different types of elements:
stocks, flows, and information
Stock
FlowInformatio
n
Stock and Flow Diagram cntd….SFD allows to represent relations among
variables in terms of equations.For Example
It becomes infeasible to solve as stocks and flows increase
Use computer simulatorsMany simulators are available, (none is open
source ) We used Vensim PLE by Ventana Systems, Inc. [4] Simulation result is time-history of variables
in terms of Graph/Table
Population = Initial(Population)+ (birth-death)dt
CDEEP : Current State of the artDistance Education through
Live Webcast and Satellite Transmission Dynamic System with Feedback Loops
4 studios for live webcast (only 1 for satellite )
Live Webcast through Internet at 100 kbps for each connection
Not many students participating in this program
Our Work Modeled Webcast and EDUSAT parts
independently Applied iterative approach to develop the
model Variable Units Initial value/ assumption
Total number of Students
Students 20
Number of courses courses 20
Quality of video dimensionless
between 0 and 1
Total available bandwidth
Kbps 8 Mbps
Bandwidth per connection
Kbps/student
Ideally 100 kbps
Student satisfaction dimensionless
between 0 and 1
Server Performance dimensionless
between 0 and 1
Initial Webcast Model
Causal Loop Diagram
Initial Webcast Model
Stock and Flow Diagram
joining new students
Students Leaving
Simulation Results
Consistently 1
Equilibrium
Bottleneck
ObservationsNumber of Students becomes constant (=200
student) after 24 monthsIncreasing number of courses doesn’t helpBandwidth is the only bottleneck Server is always underutilizedLimitations
MHRD grants can be used to bring in more resources, e.g. Bandwidth
Student feedback does matterMarketing issues can not be ignored
Modified Webcast Model
Causal Loop Diagram
Modified Webcast Model
Stock and Flow Diagram
Becomes 1 Gbps after 24
months
From 4 to 6
Simulation ResultsOne more here
Server Overload
edHuge increment due to increase in
BW
ObservationsGrants can be spent for different resources
Bandwidth increase much neededIf bandwidth is increased, server will become
overloaded after 3 semestersNo. of courses limited by no. of studiosMarketing issues are very important
Feedback from students will influence no. of courses
Similarity of syllabus with other universities affects inflow
EDUSAT ModelTransmission through EDUSAT satelliteDedicated 1 Mbps uplink and 500 kbps
downlinkStudent Interactive Terminals (SIT) for
receptionCurrently 72 Remote Centre (RCs), mostly
engineering colleges RC coordinators and Instructors to ensure
proper functioning
EDUSAT Model
Causal Loop Diagram
EDUSAT Model
Stock and Flow Diagram
ResultsEffect of relevance of courses
Results
Optimal: 20 courses and 0.7 marketing will reach 373
Number of courses vs. number of students Marketing vs. number of studentsafter 18 months
ResultsEffect of Distribution of Incoming Grants Optimal mix : 20 courses and 0.7 on
marketingGrants
Enter Here
Observations Attention needs to be paid on publicizing
CDEEP programs and encouraging student to join CDEEP
Effect of grants visible after 12 monthsOptimal mix : 20 courses and 0.7 marketing
efforts
SDModel : FeaturesCurrent simulators are all proprietary
applicationsvery limited collaboration among them
No truly successful open source System Dynamics model builder currently available.
Studied SystemDynamics Simulator[8] Huge code without proper documentation
Prepared a higher level flowchart of a model and its constituent model components. Referred an initiative SD Info Model[9]
System Dynamics Model
Dark line shows
containment
Dotted line shows
information flow
ConclusionSystem Dynamics proved to be an important
tool for modeling CDEEP system Models were verified by CDEEP staffResults obtained may help in improvement of
existing system
Future workRecommendations made may be validated by
implementing them over the actual CDEEP system
PublicationPoster titled “Using System Dynamics to
Model and Analyze a Distance Education Program” accepted in International Conference on Information and Communication Technologies and Development (ICTD) 2010.
References[1] McKansey Global Institute. Report on Emerging global labour
market,2005.
[2] John Morecroft, Strategic modeling and business dynamics: a feedback systems approach , Page no. 106
[3] Deepak B. Phatak Kannan M. Moudgalya and R. K. Shevgaonkar. Engineering education for everyone: A distance education experiment at IIT Bombay. Frontiers in Education, 2008.
[4] System Dynamics Modelling, A Practical Approach, Chapman & Hall, 1996.
[5] http://www.cdeep.iitb.ac.in/
[6] http://www.vensim.com/
[7] http://www.public.asu.edu/~kirkwood/sysdyn
[8] http://sourceforge.net/projects/system-dynamics
[9] http://sourceforge.net/projects/sdinfomodel
Thank You
Appendix1 : EDUSAT ModelVariable Equation/Initial Value
Number of students INTEG (inflow-outflow, 100)
Inflow DELAY FIXED( (Average student satisfaction *Number of RCs*Number of transmitted courses*Quality of Transmitted Video) /15, 2, 50 )
Outflow (1-Average student satisfaction)*(1-Quality of Transmitted Video)*Number of students/10
Marketing about CDEEP programme
IF THEN ELSE(Grants from MHRD>0, 0.7 , 0.2 )
Relevance with other university syllabus
0.8
Quality of Transmitted Video
Equipment Condition at RC
Appendix2 : EDUSAT ModelVariable Equation/Initial Value
Number of RCs DELAY FIXED( RC Instructor's Motivation*Marketing about CDEEP programme*600,12, 25 )
Equipment Condition at RC
IF THEN ELSE(Support staff for Equipment Maintenance>10, 0.8, 0.5 )
Incentives for RC Instructor
0.5
Grants from MHRD STEP(1e+08, 24 )
Number of transmitted courses
IF THEN ELSE(Number of studios*11>10+Feedback from students/5+2*RC Instructor's Motivation, INTEGER (Number of studios*6+Feedback from students/10) , Number of studios *11)