Stock and flow diagram - Revision history

Tomyk007 at 14:40, 26 January 2014

2014-01-26T14:40:14Z

Tomyk007 at 14:36, 25 January 2014

2014-01-25T14:36:33Z

Tomyk007: /* Shipping delay */

2014-01-25T14:35:18Z

‎Shipping delay

Tomyk007: /* Interests */

2014-01-25T14:35:06Z

‎Interests

Tomyk007: /* Definition */

2014-01-25T14:25:55Z

‎Definition

Tomyk007: /* Definition */

2014-01-25T14:25:36Z

‎Definition

Tomyk007 at 14:23, 25 January 2014

2014-01-25T14:23:07Z

Tomyk007: /* Definition */

2014-01-25T13:35:56Z

‎Definition

Tomyk007: /* Auxiliaries */

2014-01-25T13:30:07Z

‎Auxiliaries

Tomyk007: /* Tutorial in VenSim */

2014-01-25T13:26:12Z

‎Tutorial in VenSim

← Older revision		Revision as of 14:40, 26 January 2014
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	If some element A is mentioned in the equation or initial value of element B, you should first connect these elements with a link going from A to B and only then type the expression in the properties of B.		If some element A is mentioned in the equation or initial value of element B, you should first connect these elements with a link going from A to B and only then type the expression in the properties of B.
		+
		+	=Graphical representation=
		+
		+	==Graphs==
		+	Each progress of simulation can be displayed into several charts that show the change in variables for example change in time. Once the simulation run is completed, you can look at the results of your simulation. The most basic and often most useful is the strip graph - See the following figure.
		+
		+	[[File:Graf.JPG]]
		+	<ref>[http://www.vensim.com/documentation/index.html?ref_graph_tool.htm Vensim Help: Graph. VENTANA SYSTEMS, Inc. online]</ref>
		+
		+	The time axis for the graph follows the global Start time and End time, but is rounded to even numbers. The Graph tool displays single or multiple variables on a single graph. It is useful for getting the big picture of a number of variables, and for printing presentation.
		+
		+	Each software tool for modeling the system dynamics allows you to set different settings for charts as a:
		+
		+	'''Graph Type''' (Normal, Cumulative, Stack) determines how data will be represented.
		+	* '''Normal''' displays the values of the variables over time.
		+	* '''Cumulative''' integrates the values of the variables. For positive variables, Cumulative yields an upward-sloping graph over time. The cumulation for a variable begins at the first time that values for the variable are available, regardless of the global Start time. This ensures that if you shorten the time range, the values will be the same as those in a graph of the full time range. Cumulative graphs allow you to view accumulations without adding additional model variables.
		+	* '''Stack''' displays the values of the first variable normally, the second as the sum of the first and second variables, the third as the sum of the first three, and so on. All variables are stacked, including different subscript elements in a run and the same variable for different runs. For positive variables, this means that each successive variable is higher than its predecessors and that the final variable is the sum of all variables. An error occurs if the variables are from datasets with different sampling points (for example, different values of SAVEPER). Stack graphs are a convenient way of breaking down the components of a variable. It make the most sense to use stack graphs with one variable from multiple runs, or multiple subscripts from one run but rarely both.
		+
		+	==The Table tool==
		+	The Table tool is very good tool, which is included for example in VenSim<ref>[http://www.vensim.com/documentation/index.html?ref_graph_tool.htm Vensim Help: Table. VENTANA SYSTEMS, Inc. online]</ref>. It can generate a read-only table that you can scroll to review values. The resulting table displays numerical values for variables and their causes or uses. The Table tool's most common use is for detailed analysis of a narrow time range, but it is also good for displaying a lot of values on the screen and also for displaying arrays of data at a given time.
		+
		+	[[File:Table.JPG]]
		+
		+	==Stats==
		+	The Stats tool is also included in VenSim<ref>[http://www.vensim.com/documentation/index.html?ref_graph_tool.htm Vensim Help: Stats. VENTANA SYSTEMS, Inc. online]</ref> and it provides summary statistics on the Workbench Variable and its causes or uses. This tool provides a quick statistical overview of the values for a variable. The following figure shows the population statistics.
		+
		+	[[File:Stats.JPG]]

	=Software tools=		=Software tools=

← Older revision		Revision as of 14:36, 25 January 2014
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−	***IN CONSTRUCTION --[[User:Tomyk007\|Tomyk007]] 21:12, 22 January 2014 (CET)
	=Definition=		=Definition=
	A '''Stock & Flow Diagram''' (SFD) is similar to a [[Causal Loops Diagram]] (CLD) though provides a more rigourous representation. Both diagrams belong to the chapter [[System Dynamics]]. System dynamics is an approach to understanding the behaviour of complex systems over time. It deals with internal feedback loops and time delays that affect the behaviour of the entire system. What makes using system dynamics different from other approaches to studying complex systems is the use of feedback loops and '''stocks and flows'''. It depicts the structural understanding of a system - the causal structures that produces the observed behavior. It reveals information about the rates of change of system elements and the measures of the variables of the system.<ref name="props">[http://www.createadvantage.com/glossary/stocks-and-flows-diagram Stocks and flows diagram: Definition. CREATEADVANTAGE.COM. online]</ref>		A '''Stock & Flow Diagram''' (SFD) is similar to a [[Causal Loops Diagram]] (CLD) though provides a more rigourous representation. Both diagrams belong to the chapter [[System Dynamics]]. System dynamics is an approach to understanding the behaviour of complex systems over time. It deals with internal feedback loops and time delays that affect the behaviour of the entire system. What makes using system dynamics different from other approaches to studying complex systems is the use of feedback loops and '''stocks and flows'''. It depicts the structural understanding of a system - the causal structures that produces the observed behavior. It reveals information about the rates of change of system elements and the measures of the variables of the system.<ref name="props">[http://www.createadvantage.com/glossary/stocks-and-flows-diagram Stocks and flows diagram: Definition. CREATEADVANTAGE.COM. online]</ref>

← Older revision		Revision as of 14:35, 25 January 2014
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	===Shipping delay===		===Shipping delay===
		+
		+	Create working simulation based on following proposal of Stock and Flow Diagram and equations.
		+
	[[File:Shipping delay.JPG]]		[[File:Shipping delay.JPG]]

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 ===Interests===
 [[File:Interrests.JPG]]
@@ Line 309: / Line 312: @@
 # Savings = INTEG(interest,100)
 # TIME STEP = 0.0625
 ===Shipping delay===

@@ Line 10: / Line 10: @@
 * Flows
 * Quatified feedback loops
 '''Example of Stock and Flow Diagram - Child-adult population model'''
 [[File:Sf example.JPG]]
 '''Shipments'''
 [[File:Sf example2.JPG]]

@@ Line 12: / Line 12: @@
 '''Example of Stock and Flow Diagram - Child-adult population model'''
 [[File:Sf example.JPG]] [[File:Sf example2.JPG]]
 =Rules=

@@ Line 10: / Line 10: @@
 * Flows
 * Quatified feedback loops
 =Rules=
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 * Stocks are always changed by flows
 * In general, the formulas for the flows will depend on things that are changing (state)
 =Symbols=

@@ Line 6: / Line 6: @@
 By explicitly identifying Stocks - reservoirs which change over time, and Flows, which are responsible for changes in Stocks, the resultant insight explicitly depicts the manner in which things change.
+'''Stock & Flow Diagram i based on Causal Loops Diagram and captures:'''
 * Stock
 * Flows

@@ Line 152: / Line 152: @@
 == Auxiliaries ==
 [[File:Variable.JPG]]
 Auxiliaries are used to '''define some intermediate concepts'''. Auxiliary can change '''instantaneously''' according to the specified formula.
 == Parameters ==

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 '''Task'''
-Convert the following model in the simulation environment Vensim.
+Convert the following model in the simulation environment VenSim.
 [[File:CL.JPG]]