Supporting Material is available for this work. For more information, follow the link from
the Table of Contents to "Accessing Supporting Material".
Table of Contents
A Study of Connect Dynamic Data Source to Improve the
Simulate Technique for the System Dynamics
1 Introduction
1.1 Study the background and motive
Remember the evolution of the current of thought of the management in recent
years, analyze by traditional divided into classes and categories and alone already
and gradually, change into current whole thinking, by the Jay of MIT. W.
Fonester the System Dynamics that professor develop, main is helping the
govemor while considering problem and ckcision, in addition to considering the
jproblem of the section of the system each of, still notice these problems the
operation of the mechanism of the system and pass after postponing, influence
toward whole system.
The tradition modd of the System Dynamics by two main part constitute:
@ Model Component : Can be divided in to aocunulde the label variables,
rate variables, variable and data stream eic., It describe the causal
tdationship of the dements of the system.
@ Simulate Parameter : the constant or data used by model. Do not include
the fami.
In the tool of the simulation of the dynamics of the system of the tradition: as
STELLA, iThink, Vensimand er. of PoweSim, parameter is and modd
component together store in modd, and the importation and modification of the
parameter, is also an usage to the input tools provide by the simulation toals,
mod of the system dynamics is in smulde process, and can't obtain the data of
the simulation from the exterior of the modd; The result that also cant will
imitate- for example, each variable is outside the value of each period- store in the
exterior of the modd.
Butin regad to actual situation application, the closed interfane of the traditional
simula tools of system dynamics is not support the damand in decision of the
enterprise today. First, The environment of the enterprise of today will change at
any time because of factor of the exterior, a year ago the estimate done, may must
check these factors in today whether would to predict result contain any influence
because the war, natural calamity and politics and technical environmental
changed. And enterprise is in usually operaie process, also may want at any time
according to current data- as material, funds and finance etc.- the estimate that be
the short date to the future. The modal of the system dynamics can use the result
of the past project, but the data of the simulation must input again completely, and
cantt use current data of the dynamic state of the enterprise. If the moda had
several hundred variables , It will suffer very hig restrict on the usage.
Besides, in the analytical of the policy and soenanio, the traditional tool of the
simulation of system dynamics is whilesmulde each policy or scenario, must
Teset the data, execute the simulation process, then minute down to the result
Project in the policy or scenario considered is more much, resetting the number of
times of the parameter more multifarious. If all complete with the hand, will bea
work of fragmentary and high rate of the mistake. It is limited the usage of the
Tepdiition of the modal that tedious input data procedure and dosed data format.
Therefore, when the project end, it usually look in dark file room that the moda
spend cost and wisdom. It is huge squanderin the resource and person usage of
the enterprise.
But if we move the data the tradition modd of the system dynamics to exterior of
the moda, becoming independent data source. The modd obtain to data from the
exterior data source in smulate process. The result can also store in exterior data
source. in the structure :
@ Manager can used the online data of the enterprise, obtaining the result of the
simulate of the short date.
@ = Wren the exvironment changed, manager can used online data of the
enterprise, chedk the influence of the past result because the environment
changed.
@ = Inthe policy orsoamio simulation. User can store the parameter of each
policy or scenario in exterior data source and used the data execute simulate
yaocess.
Main purpose of this research, at inquire into how to strengthen related structure
of the technique of simulation of system dynamics with the dynamic data source,
and according to study the result devdlop simulation tool, toing be used as to
configure the identification of the benefit
1.2 The purpose of study
The purpose of the study is :
@ — Research the structure of how to strengthenthe technique of system
dynamics simulation to use dynamics data source.
@ = Design the simulation tools to provide to read and wiite exterior data source,
check the possihility of support enterprise operation.
2 The structure of how to strengthen the technique of system dynamics
simulation to use dynamics data source
2.1 Combine the model of system dynamics with dynamics data
Tn regard to the mode of the system dynamics combine with the dynamics data,
Can be divided into three aspect :
The modd of system dynamics read from dynamics deta.
The modd of system dynamics write to dynamics data.
The structure of strengthen the moda of system dynamic to use dynamics
data.
2.1.1 The model of system dynamics read from dynamics data
The modd of system dynamics read from dynamics data in the stale :
@ — Set the initial value of variable
When the stat of simulation, the modal read from dynamics data. The
eta read one time on whole simulate process. It is usually usage with
the analysis of policy or scenario.
It is divided into threelevd the analysis of policy or soanatio :
m= Adjust the flow of the model.
= Increment or decrease the element of the model.
m= = Adjuse the value of variable.
In changing the daia in the system, we would usually use data to
describe the policy orsoenario - for example, the amount of loan, the
enforce and abolish year of the law, the total of employ worker etc, - .
We canstore the value of describe the policy or scenario in the exterior
data source. The modd of system dynamics read from data sourve in
start simulation and output the result of each policy of scenario.
@ — Set the value of variable on the start of phase
Tneach phase smile beginning, the moddlzead value from exterior
data source Its characteristic has:
™ ~~ Because each phase before simulating will read once, read
frequency with smulaie the length of time and different Simulate
time to grow more, the data reads more frequent
@ = Themodd is random teed dala for to simulate the random factorin
teal wold probably.
According to above need the way of the model of system dynamics read
from exterior data source have :
= Repeat -
Read same record when read exterior data.
m = Sequence-
Read exterior record in sequence.
= Random-
Read exterior record in random.
2.1.2 The model of system dynamics write to dynamics data
Tnzegard to on the other hand, the modd of system dynamics read from
dynamics data in the stale :
@ Write to new data source
The moda write the result of simulate to a new dala source. Its
characteristic has:
The data source is amply.
Direct append data record. Do not need seek key value.
‘The method is collection smulate value. And use in others information
system(For example Decision Support System etc.,) analyze.
Fill empty field in database
The modd wite the result of simulate to the data record of data key
match with record key. Its charactezistic has:
The data source is not empty.
The moda should seeking key value before write data.
Tf it have part dement value is unknown in the simulate project. We can
store the project value in a database and execute simulae. The tools will
simulate to base on the data and fill result to empty data.
Aocording to above need, the way of the model of system dynamics
‘wiite to exterior data source have :
Single append -
Multiple append -
The modal append data when the condition is tue. The condition
have:
@ = Fechsmuide phase begin.
© = Specific simulate phase begin
@ The value of specific variable out the range.
Single fill -
The modd fill deta to match record after simulate ending.
Multiple fill-
The modd fill data to match record when the condition is tue The
condition have :
@ = Fachsmuide phase begin
@ = Specific simulate phase begin
@ Thevalue of specific variable out the range.
2.1.3 Strengthen the model of the dynamics of the system with the data
of the dynamic state it configures basic need
Inaction to providing the above of reading way, the modd of the dynamics
of the system integrate with the database, must still meet following need:
@ Looser coupling
If just move the dda of the emulation in the modd of the dynamics of
the system out the modd, and store in lone sourve of the data, Also cant
Ie the modd of the dynamics of the system reach first need of this
research here - Provide to carry on the function of the emulation with the
data of the dynamic stale. For canning let the modd of the dynamics of
the system link the business enterprise in the source of the data of every
kind of different type, The request of the conjunction that is at both,
must mee following need:
m= = =©Thesourve of the data must can establish, safeguard and move
alone in aciition to, do not need the usage imitates the importation
of the tool and manages the interface.
=) = Themodd must can link and move in addition to various different
databases.
@ = = Modd inof besic dollar piece the - if accumulate the quantity,
amount of rate and win to lie the variable efc.- can not access the
database directly.
@ It do not use the article of the database in the model
In addition to datafomm Table __, the modd do not link other attide
of the database, and the form of the dala also wants to become an artide
alone in the mods, toing nainiain the flexibility of the modd. Itsmain
purpose is:
m@ = Letmodd and sourve of the data caned be independent each other
m@ = Avoid being databese the construction changes, the modal also
‘wants along with change.
m@ = Atdo not link the station of the sourve of the dala, the modd
needs only least modification can immediately carry on the
emulation
2.2 The mode of the dynamics of the system combine with the data of the
dynamic state the structure
According to above need, the suggestion of this research configures to traditional
dynamics moda of the system, carrying on to change the followingly:
@ Element of the" source of the data" of the increment:
Increese the dement of the" source of the data’ in modal of the dynamics of
the system, be used as the" window way" of the mod of the dynamics of
the system and conjunction of the dala of the exterior That dementis nain
to define following data:
@ = Desctibe the souree of the data that moda link with the SQL.
@ = While initating every time, the modd reack the way of the deta.
@ = While imitating evey time, the modal wiites in the way of the data
@ The change of the source of the data of the variable:
‘The source of the data of the variable of the model of the dynamics of the
system of the tradition, can be divided into two types: the calculate type of
the luck or function of the form. In this study the modd of the programming,
the source of the variable is in addition to the above both, also caming
define to read from the attidle of the source of that data that variable.
‘The structure of the dynamics of the system of the programming of this
research is shown as diagram bdow:
Tradition model
The model of add “ Data Source” element
figure 3.1 The mode of the dynamics of the system combine with the data of the
dynamic state the structure
Configure the dynamics of the system of the coordination and database with.
this, main consideation lies in:
@ Source of the data and separation of the model of the dynamics of
the system .
@ = The data uses again.
3 The system that provide the dynamic state the data to access the function the
dynamics imitates the tool- Maria
3.1 Brief introduction
The Maria studies the structure of the system of the programming according
to this, its data for providing the dynamic state developped acoesses the
system of the function the dynamics the emulation the tool, Its function and
special features includes:
@ = Provide and STELLA, theiThink dragsalong dose byly the put type
establishes the method of the model. User can from the dollar piece
dish top sdlect the artide, and drag to the modd again drawing board
top establish the moda.
e@ Add theaticle of the source of the data, be used as the window way
‘that mod of the dynamics of the system and exterior data source link.
The moda can obtain the data from the source of the data of the
exterior through the article of the source of the data, imitating the data
to also deposit the sourve of the data by the soutve of the data.
@ = Using the interface of ADO that Microsoft develop is used as and the
interface of the software that sourve of the data link. Can link the
source of the data of various types.
3.2 Dollar piece structure
In the program in Maria, with the structure of the direction( Object Orient)
of the attide, the each dollar that describe the moda of the dynamics of the
system piece, Its each artide inherits the relation,such as figure, 4.1 show:
%O@%?
Figure 3.1 The Dollar piece structure of the Maria
3.3 System structure
Main appearance of the Maria,such as figure4.2 show:
——————————————————— i
35 ED wa ORG) aM
Sus anSe
Bx ce+o\ o8f
e—
founeen mw
Figure 3.2 Main appearance of the Maria
Whole the system of Maria is by fourare pattially the composing:
Drawing board of the model: The each piece and its pass of the
cause and effect that show the model of the dynamics of the system
connects. User can from tool dollar in the row piece the dish wins
election to choose a piece, delay any more to put to the drawing board
to establish the model. Provide in the model in Maria at the present
time one kind of piece
= = Level Variable : Describe the static quantity in system.
ils
figure 3.3 Level Variable
m@ Rate Variable: Describe the dynamics quantity insysten
ila
figure 3.4 Rate Variable
m@ Assist Variable : Indicate in model although not affect to
accumulate directly the quantity increases or decrease, can affect
the quantity of the rate or other variable changes the quantity.
Blt
figure 3.5 Assist Variable
= Data flow : Indicate each variable in model the fluxion of the
infonmetion.
Blak ‘Blast
figure 3.6 Data flow
= Data Source : Define the model of the dynamics of the system
comnect of sourve of the data of the exterior with to write in/ read
way, Is the window way that model of the dynamics of the system
and exterior data sourve commumnicaie.
‘Blast
figure 3.7 Data Source
= = Statistical chart : Providing the value of each element that
imitate mode's lead designs the function of the statistical chart.
Blt
Ps
figure 3.8 Statistical chart
m= Statistical Table : Providing the value of each element that
imitate moda''s lead designs statistics the function of the fom.
ili
figure 3.9 Statistical Table
And establish the model of the dynamics of the system in Maria, is
from the dollar of the row of the tool piece the dish wins election to
take a piece, then drag along it puts to the version of the diagram of the
moda combine. As the figure 4.9 show:
Pil
|
fio) Se
figure 4.9 Establish the model on the version of the diagram of the model
@ Model manager : Show current model in the editor with the diagram
of the form of the tree and it include a piece.
figure 4.10 Model manager
e Attribute Manager : The article that manifestation choose at the
jpresent time to the atiribute.
fae : IE ~]
figure 4.11 Attribute Manager
@ Formula Manager : Show the formula of the dement of the system.
3.4 The dynamics of the system combine with the exterior data source
Tn Mania, the link of the model and source of the data of the exterior is solid
to meke main be divided into two pats:
@ Data Source element :
The Maria is different from the tradition system dynamics imitates the
tool of, consisting in adding namely first"Data Source", In this, it is
main to is a definition:
m= ~The source of the data of the exterior that model of the dynamics
of the system link
@ ~~ Read the frequency and way of the hour of the data
=) = While witingin the chia of frequency and way.
@ = Traditional system dynamics dollar the modification of the piece:
In the structure of the model of the dynamics of the system in Maria,
accumulate the quantity, amount of rate and variable of the assistance
to all compare the traditional system the dynamics dollar the piece had
another two attribute :
m@ Read the data : Set up to be the model of the dynamics of the
system to read from the source of the data of the exterior data,
‘want to be through that data source dollar piece in of specify the
colunm reads data, and set up for the value of the dollar's piece.
@ Write the data: Set up when the model of the dynamics of the
system wants to write in the data to sourve of the data of the
exterior, current dollar the piece is worth to want the source of the
daa and column thet wite in.
Model Data Source
figure 4.12 Maria is in the structure of the model, the link of the model and
source of the data
3.5. Model identification
3.5.1 Enactment of the model of the foundation:
In this stanza, this research with the university's student gets stripe the model
for example, the link of solid model of the dynamics for making the system
and sounve of the data of the exterior.
Assumption have a new- established university at the present time, establish
early school to only have 100 hig a newbom, manage the authorities the
project to recruit every year 300 freshman, and each academic year be over
hour
m@ = The freshmanreach 60% can tise to the sophomore.
m@ = The sophomore reach 70% can tise to the junior
@ = Thejunior reach 80% can rise to the senior
m@ = Thesenior reach 90% can graduate smoothly.
Want to be with that university of the analysis of the dynamics of the system.
to solicit students after few year, the number of the student of each grade
assigns. First, we first in the version of the diagram of the model in Maria,
Wales
aia)
=
SO
ae ir
—SSssss }|
as i}
— a
i
es
sna
| ca
(iss cae) ja
figure 4.13 The model of university study is design with MARIA
‘Thet modal in the dollar of the containment the piece has:
m= Label Variable :
m= UA: The freshen total (Unit : Person)
= UB: Thesophomrr total (Unit : Person)
= UC: Thejuniortotal (Unit : Pason)
= UD: TheSazior total (Unit : Person)
m= = Rate Variable:
m= = NEW : The freshman who enter school when academic year start
(Unit : Person / Year).
m= AB: Thetotal of the academic year to start is freshmanon rising to
sophomor of student(Unit : Person / Y ear).
= BC: The total of the academic year to start is sophomor onrising
to thejunior of studeni(Unit : Parson / Year).
= CD: The total of the academic year to start is junior on rising to
the sanior of student(Unit : Person / Y ear).
= = GDU: The total of The student who graduate when academic year
start(Unit : Parson / Year)
And the calculate type of the luck in the model indicates with the format
of iThink, then for
@ ~=UA(t) =UACt- di) +(NEW- AB) * ct
INIT UA =100
INFLOWS:
NEW =300
OUTFLOWS:
AB =UA*0.6
e@ UB(t) =UB(t- di) +(AB - BC) * dt
INIT UB =0
INFLOWS:
AB =UA*0.6
OUTFLOWS:
BC =UB*0.7
@ UC(t) =UC(t- dt) +(BC - CD) * dt
INIT UC =0
INFLOWS:
BC =UB*0.7
OUTFLOWS:
CD =UC*08
e@ UD(® =UD(t- dt) +(CD - GDU) * at
INIT UD =0
INFLOWS:
CD =UC*08
OUTFLOWS:
GDU =UD*09
The model establishes after completing, we choose the Maria the form of
the function of" imitate the '" time the enactment", or press emulation
button in the row of the tool. Will show to set up to imitate the dialog
box of the period on the appearance:
emmm:ail = s]#P0 S
ER : |= i
BES : |
x mH |
figure 4.14 Set up to imitate the period
In this example, we anticipate to imitate should the variety of the inside
enrollment of 30 years of the university, so the period of the emulation
settles to 1-30 periods, the unit of time is a" year", again because at
current we do not plan to do different policy and outside environment
‘under imitate result of comparison, so only need to be imitated once.
Set up imitate after period, we choose the Maria the form of the function
of" imitate" carry out", The Maria will start carrying on the emulation
nenwy.
Imitate after completing, we move the cursor of the mouse to statistical
chart dollar piece, then press right key of the mouse, the appearance will
show at appointed inside of the period of the emulation namely, should
the variety of the number of the student of each grade of university:
figure 4.15 Simulate result
Can find by above statistical chart, at start the eighth that solicit students
to the ninth academic year, the number of each grade will maintain to fix,
number with freshman at most, senior is least. And on another tool
iThink of emulation, we also see the result of the homology:
figure 4.16 The result of simulate with Think
3.5.2 Analysis of the policy and scenario:
In last a stage, we already can through the function of the emulation of the
Maria, carry on the estimate to the future, and in this stage, we will explain
the model of the dynamics of the system how to link the application of the
model of the deta of the exterior
Suppose the school manage the emulation in last a stage of the process of the
authorities, have known the school the enrollment in 30 yearses of the future
the variety, but, if we when the beginning of the school solicit students, big a
the number of the freshman different, whether would to the number of each
grade of school cause influence in the days to come?
Establish a new form “TestRead” of the data in with Maria carried on imitate,
us first can the database of Northwind in school:
ID UIDEFAULT
1 300
2 500
3 1200
Figure 3.17 Store the data of different scenario of the policy the form the
TestRead
There is two columns in TestRead form of the data: {There is two columns in
TestRead data form} The ID stores the code of the policy, and the
UIDEFAULT then stores When the beginning of the school solicit students,
hig a the number of the freshman.
Join an article of the source of data in set up form of the data after, us retum
to Maria, previously ex- model, and set up its"Data Source" Attribute to link
the database of Northwind of the school:
figure 3.18 Set up the data source attribute
And in sourve of the data of" SQL describe", we with the description of SQL:
SELECT *
FROM TestRead
Request the system from the TestRead in the database the form of the data
obtains the data.
Pepe ees
i
ieee el jAt=e) [Ba5\8
Sx pe ON 8 wm)
t= Ca
a _*|
FROM TESTREAD:
(2me]_xeaj
= — = _ oil
a I z l
EO j WN BesSam tia”
figure 3.19 Set SQL Statement
Immediately after, we data source dollar piece of" read frequency" establish
for" before imitating read;" read way" belong to the sex establishes for" in
proper order';Let data source is in the emulation of the every time front,
meeting from the first beginning of the data form in order read data into
mod.
Then, we choose to accumulate to measure a piece UA(the freshman number),
set up its" read the data!’ Athibute.
SF] wD wats 2l@\x)
‘oB/Res | jA@ee) (Sa5\8
[Bx@ cess |Shm) |
|—xs—— past _ eat = me BD
a om
Aner
J ————— af
ogo) a I = l
Bent) DO | Byes Memon wea lfaM enim J WN Bossom ris”
figure 3.20 Set up the data link of elements
Set up after completing, we choose the Maria the form of the function of"
imitate"-" time set up", Will show to set up to imitate the dialog box of the
period on the appearance. This time because we wants to imitate three kinds
of different scenarios under of result of the emulation, so establish to three"
emulation number of times", request the Maria the repetition the emulation
three times, all imitates to Issue 30 from Issue 1 each time, the unit of time is
a" year".
Connect down, like that of last time, we choose the Maria the fonn of the
function of" imitate"-" carry out", Different from last time is, in imitate after
open statistical chart, can saw result that the same piece of top manifestation
of the diagram three times imitate, and emulation in every time, Maria would
according to source of the data current record, solicit students the beginning
big a the number of the freshman establishes for 300 and 500 and 1,200
SossHSBEHESEHRSS THESES
ote a ee eT ee MNH OME RV EDA RSA SMHS aD
figure 3.21 The result of changing freshman total
By last diagram in can find, even while starting solicit students, hig a the
number of the freshman is different, but along with the changes of time, the
tumber of the last grade all would be same.
4 Conclusion
4.1 The application of the actual situation of the information of the
business enterprise
If the system that study this move the information of the business enterprise the
Taanagement the aspect from the laboratory, that application realm again is how?
At current the information of the business enterprise manages the structure,
having headed for the coordination from the traditional dispersion The
infonmation of the business enterprise inner part were integrated in the
information sourve of the business enterprise, and business enterprise in if trade
the information system of the type of the management system( TPS) and
management information system( MIS) or decision support system( DSS), are all
from read or write in the data in the business enterprise data source. As the figure
4.1 show:
DSS
Data Source
Figure 4.1 The structure of the system of the information of the business
enterprise
If the structure of above diagram and speech, then traditional dynamics model of
the system is after increasing to link the function of the sourve of the data of the
exterior, main and applied direction can be divided into the both side:
@ Making use of the model of the dynamics of the system obtains the data of
the business enterprise to take into the emulation, then save the result after
imitating to retum to data of the business enterprise, toing provide the
business enterprise the other information the system the usage. As the figure
42 show:
¥aspiti epzeTteil |- weave |
(TPS) (MIS) (Dss)
pee
fiat
¥9>~>@EO%
Figure 4.2
Is shown as diagram above, the business enterprise can be used as its
analytical data to source of the data for model of the dynamics of the system
to imitate, imitating the result writes again to retum the source of the data of
the business enterprise in, be used as the source of the information of the
decision support system( DSS) and system( MIS) of the information of the
management or analysis of the system of the information of the top executive
or manifestation.
@ Be used as the mode of the core of the decision support system( DSS) with
the modd of the dynamics of the system:
Making use of the mode camies on to imitate and predict, ising in the
structure of the decision support system very important and analytical tool,
the structure of the mode of the decision support system of the tradition most
likely with the mode of mathematics and logic reasons logically the mode for
lord, and model of the dynamics of the system is in provide and the tool that
exterior data source link after, also can brought into the sub- system of the
mode of the decision support system, being used as the decision support
system the decision a wreath of the mechanism. As the figure 4.3 show:
¥eoBiti spzeTei Mra vei
(TPS) (MIS) @ss)
i.
¥9 >@®EO'%
Figure 4.3
5 Consult the cultural heritage
English
@ Jay W. Fonester. 1961. Industrial Dynamics. MIT Press
© Augusto A. Legasto, Jr, Jay W. Fonester, James M. Lyneis. 1980. System
dynamics. North-Holland Pub. Co. ; New York
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