vending

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Uri_dolphin3 Uri Wilensky (Author)

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Model group CCL | Visible to everyone | Changeable by group members (CCL)
Model was written in NetLogo 4.1pre1 • Viewed 74 times • Downloaded 6 times • Run 0 times
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VERSION

$Id: vending.nlogo 38634 2008-03-11 13:35:54Z everreau $

Each student stands in line to get something from the vending machine. For each vending machine, there is a certain probability that it will give out a prize. After each student gets something from the vending machine, he picks a random line to stand at the end of. If the line he picks is too long, he just moves to the back of his own line, which is known not to be too long.

NOTE: "wealth" in the UI refers to prizes won, not prizes won vs. money spent

WHAT IS IT?

The students stand in lines to get an item from a vending machine. Each vending machine has a certain probability of giving away a prize with the item. After they receive the item, they move to the back of their line. Students can change the line they are in at any time, taking place at the end of the line.

For further documentation, see the Participatory Simulations Guide found at http://ccl.northwestern.edu/ps/

HOW TO USE IT

QUICKSTART INSTRUCTIONS:

------------------------

Teacher: Follow these directions to run the HubNet activity.

Optional: Zoom In (see Tools in the Menu Bar)

Optional: Change any of the settings. Press the GO button to start the model.

Everyone: Open up a HubNet Client on your machine and input the IP Address of this computer, type your user name in the user name box and press ENTER.

Teacher: Have the students move their turtles around to acquaint themselves with the interface. Then press the INFECT NetLogo button to start the simulation. Watch the plot of the number infected.

Teacher: To rerun the activity with the same group, stop the model by pressing the NetLogo GO button, if it is on. Change any of the settings that you would like. To overlay the new run's plot data change the value of the slider DATA-SET. If you set DATA-SET to a value that already had data in it, the new data will over-write the old data. Press the NetLogo RE-RUN button. Restart the simulation by pressing the NetLogo GO button again. Infect some turtles and continue.

Teacher: To start the simulation over with a new group, stop the model by pressing the NetLogo GO button, if it is on and follow these instructions again from the beginning.

BUTTONS:

--------

SETUP - clears all turtles and patches and the plot. This should only be pressed when starting out with a new group of users since all data is lost.

GO - runs the simulation

RE-RUN - cures all turtles, and clears the current plot pen selected with DATA-SET. This should be used to setup the model again for collecting more data or running the model again with the same users connected.

CREATE ANDROIDS - adds randomly moving turtles to the simulation

INFECT - infects some of the turtles in the simulation

NEXT >>> - shows the next quick start instruction

<<< PREVIOUS - shows the previous quick start instruction

RESET INSTRUCTIONS - shows the first quick start instruction

SLIDERS:

--------

NUMBER - determines how many androids are created by the CREATE ANDROIDS button

ANDROID-DELAY - the delay time, in seconds, for android movement - the higher the number, the slower the androids move

INITIAL-NUMBER-SICK - the number of turtles that become infected spontaneously when the INFECT button is pressed

PERCENTAGE-INFECTION - sets the percentage chance that every tenth of a second a healthy turtle will become sick if it is on the same patch as an infected turtle

DATA-SET - sets which plot pen the data from this run will be plotted with. This is useful for comparing several runs of the model to one another. All pens are cleared by SETUP.

SWITCHES:

---------

WANDER? - when on, the androids wander randomly. When off, they sit still

SHOW-ILL? - when on, sick turtles add to their original shape a red circle. When off, they can move through the populace unnoticed

SHOW-ILL-ON-CLIENTS? - when on, the clients will be told if their turtle is sick or not.

MONITORS:

---------

TURTLES - the number of turtles in the simulation

NUM-INFECTED - the number of turtles that are infected

PLOTS:

------

NUMBER SICK - shows the number of sick turtles versus time

CLIENT INFORMATION

After logging in, the client interface will appear for the students, and if GO is pressed in NetLogo they will be assigned a turtle which will be described in the YOU ARE A: monitor. And their current location will be shown in the LOCATED AT: monitor. If the student doesn't like their assigned shape and/or color they can hit the CHANGE APPEARANCE button at any time to change to another random appearance.

The SICK? monitor will show one of three values: "true" "false" or "N/A". "N/A" will be shown if the NetLogo SHOW-ILL-ON-CLIENTS? switch is off, otherwise "true" will be shown if your turtle is infected, or "false" will be shown if your turtle is not infected.

The student controls the movement of their turtle with the UP, DOWN, LEFT, and RIGHT buttons and the STEP-SIZE slider. Clicking any of the directional buttons will cause their turtle to move in the respective direction a distance of STEP-SIZE.

The students can watch the progress of the disease in the NUMBER SICK plot which is identical to the plot of the same name in NetLogo.

THINGS TO NOTICE

No matter how you change the various parameters, the same basic plot shape emerges. After using the model once with the students, ask them how they think the plot will change if you alter a parameter. Altering the initial percentage sick and the percentage infection will have different effects on the plot.

THINGS TO TRY

Use the model with the entire class to serve as an introduction to the topic. Then have students use the NetLogo model individually, in a computer lab, to explore the effects of the various parameters. Discuss what they find, observe, and can conclude from this model.

Comments and Questions

Please start the discussion about this model! (You'll first need to log in.)

Click to Run Model

globals [
  vend-lines  ;; list of vending machines containing a list students for each vending machine
  vend-positions ;; list of xcors of each vending machine

  prize-streaks  ;; list of prize streaks for each line
  wealth-distribution-list  ;; list of (num-prizes / (money-spent)
  vending-machine-colors  ;; list of colors for each line

  max-line-length  ;; the longest a line can be (determined to be 14 for the current screen size)

  ;; lists used to create the various turtles
  shape-names       ;; list that holds the names of the non-sick shapes a student's turtle can have
  colors            ;; list that holds the colors used for students' turtles
  color-names       ;; list that holds the names of the colors used for students' turtles
  used-shape-colors ;; list that holds the shape-color pairs that are already being used

  ;; misc
  clock        ;; keeps track of the number of times through the go procedure (if there is at least one turtle infected)
  max-possible-codes ;; total number of possible unique shape/color combinations

  ;; quick start instructions variables
  quick-start  ;; current quickstart instruction displayed in the quickstart monitor
  qs-item      ;; index of the current quickstart instruction
  qs-items     ;; list of quickstart instructions
]


breed [ students student ]
breed [ vending-machines vending-machine ]

students-own [
  line-number   ;; the vending machine number you are standing in line for
  money-spent   ;; the number of times student has 'vended'
  line-position ;; the place they are in the line, 1 being the front
  num-prizes    ;; the number of prizes won
  user-id  ;; unique id, input by the client when they log in, to identify each student turtle
]

vending-machines-own [goods-dispensed prizes-dispensed last-vended-prize]

to startup
  setup
  hubnet-set-client-interface "COMPUTER" []
  hubnet-reset
end 

to setup
  ca
  setup-vars
  create-vending-machines 4
  [
    set shape "vending machine"
    set size 2
    set color (item who vending-machine-colors)
    set goods-dispensed 0
    set prizes-dispensed 0
    set last-vended-prize 0
    setxy ((floor (max-pxcor / 2) * (who - 2) + 3 )) (max-pycor - 1)
    set vend-positions (lput xcor vend-positions)
  ]
  setup-quick-start
end 

to setup-vars
  set clock 0
  set max-line-length 14
  set vend-lines [[] [] [] []]
  set vend-positions []
  set prize-streaks [[] [] []  []]
  set wealth-distribution-list []
  set vending-machine-colors [red green blue]
  set vending-machine-colors lput (orange + 1) vending-machine-colors

  set shape-names ["wide wedge"  "thin wedge" "big boat" "pickup truck"
                   "nu" "uu"  "butterfly" "wolf" "sheep" "lobster" "monster"
                   "moose" "bear" "teddy bear"]
  set colors      [ white   gray   brown   yellow   green   lime   turquoise
                    cyan   sky   blue   violet ]
  ;; adjust a few colors so they don't blend in with the red infection dot too much
  set colors lput (orange + 1) colors
  set colors lput (magenta + 0.5) colors
  set colors lput (pink + 2.5) colors
  set color-names ["white" "gray" "brown" "yellow" "green" "lime" "turquoise"
                   "cyan" "sky" "blue" "violet" "orange" "magenta" "pink"]
  set max-possible-codes (length colors * length shape-names)
  set used-shape-colors []
end 

to re-run
  set vend-lines [[] [] [] []]
  set vend-positions []
  set prize-streaks [[] [] []  []]
  set wealth-distribution-list []
  ask vending-machines
  [
    set label ""
    set goods-dispensed 0
    set prizes-dispensed 0
    set last-vended-prize 0
  ]
  ask students
  [
    set num-prizes 0
    set money-spent 0
    send-info-to-clients
  ]
  clear-all-plots
end 

;; give the user some information about what the setup button does so they can
;; know whether they want to proceed before actually doing the setup

to setup-prompt
  if user-yes-or-no? (word "The SETUP button should only be used when starting "
              "over with a new group (such as a new set of students) since "
              "all data is lost.  Use the RE-RUN button for continuing with "
              "an existing group."
              "\\n\\nDo you really want to setup the model?")
  [
    user-message (word "Before closing this dialog, please do the following:"
                 "\\n  -Have everyone that is currently logged in, log off and "
                 "then kick all remaining clients with the HubNet Console.")
    setup
  ]
end 

to go
  every 0.1
  [
    ;; get commands and data from the clients
    listen-clients

   ask students with [line-position = 1]
   [
      hubnet-send user-id "Instructions:" "Click Vend!"
   ]
   ask students
   [
     send-info-to-clients
   ]
  do-plot
  set clock (clock + 1)
  ]
end 

;; observer procedure

to add-student-to-line [student num]
  set vend-lines (replace-item num vend-lines (lput student (item num vend-lines)))
  ask student 
  [ 
    set line-position num 
    set line-number num
    setxy ((item line-number vend-positions)) ( max-pycor - 2.5 - 2 * line-length line-number)
  ]
end 

to leave-line
  hide-turtle
  foreach (item line-number vend-lines)
  [
    ask ?
    [
      if (line-position > [line-position] of myself)
        [fd 2 set line-position (line-position - 1)]
    ]
  ]
  set vend-lines (replace-item line-number vend-lines (remove self (item line-number vend-lines)))
end 

;; student procedure
;; moves student to the back of the chosen line
;; if the line chosen is too long, the student will remain in the line he is currently in

to move-to-line [num]
  if line-length num >= max-line-length  ;; if the line is too long, go to the back of the current line
    [set num line-number]
  foreach (item line-number vend-lines)
  [
    ask ? [
      if (line-position > [line-position] of myself)
        [fd 2 set line-position (line-position - 1)]
    ]
  ]
  set vend-lines (replace-item line-number vend-lines (remove self (item line-number vend-lines)))
  add-student-to-line self num
end 

;; observer procedure
;; returns the number of students at a particular vending machine

to-report line-length [num]
  report length (item num vend-lines)
end 


;;vending-machine procedure

to vend [student]
  if ((who = 0 and random 10 < vend-1) or
      (who = 1 and random 10 < vend-2) or
      (who = 2 and random 10 < vend-3) or
      (who = 3 and random 10 < vend-4))
  [
    ask student [ set num-prizes num-prizes + 1 ]
    set prizes-dispensed (prizes-dispensed + 1)
    set prize-streaks (replace-item who prize-streaks (lput last-vended-prize (item who prize-streaks)))
    set last-vended-prize 0
  ]
  ask student [ set money-spent money-spent + 1 ]
  set goods-dispensed (goods-dispensed + 1)
  set last-vended-prize (last-vended-prize + 1)
  set label last-vended-prize
end 

to-report average-prizes-in-line [num]
let num-prizes-list 0

  set num-prizes-list [num-prizes] of students with [line-number = num]
  ifelse (sum num-prizes-list = 0)
    [report 0]
    [report mean num-prizes-list]
end 

to do-plot
  set-current-plot "Prizes Won vs. Money Spent"
  histogram ([num-prizes / money-spent] of students with [money-spent != 0])
end 

;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Quick Start functions ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;

;; instructions to quickly setup the model, and clients to run this activity

to setup-quick-start
  set qs-item 0
  set qs-items
  [
    "Teacher: Follow these directions to run the HubNet activity."
    "Optional: Zoom In (see Tools in the Menu Bar)"
    "Press the GO button."
    "Everyone: Open up a HubNet Client on your machine and..."
      "type your user name, select this activity and press ENTER."
    "Teacher: Have the students change their move-to slider to..."
      "acquaint themselves with the interface."
    "When the students receive the 'Vend Now' instruction ..."
      "they should click VEND"
    "Teacher: To start the simulation over ..."
      "stop the model by pressing the NetLogo GO button, if it is on..."
        "click RE-RUN to reset the data and the plots, and press GO"
    "Teacher: To start the simulation over with a new group,..."
      "stop the model by pressing the NetLogo GO button, if it is on..."
        "click SETUP, and follow these instructions again from the beginning."
  ]
  set quick-start (item qs-item qs-items)
end 

;; view the next item in the quickstart monitor

to view-next
  set qs-item qs-item + 1
  if qs-item >= length qs-items
  [ set qs-item length qs-items - 1 ]
  set quick-start (item qs-item qs-items)
end 

;; view the previous item in the quickstart monitor

to view-prev
  set qs-item qs-item - 1
  if qs-item < 0
  [ set qs-item 0 ]
  set quick-start (item qs-item qs-items)
end 

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Code for interacting with the clients ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;; determines which client sent a command, and what the command was

to listen-clients
  while [ hubnet-message-waiting? ]
  [
    hubnet-fetch-message
    ifelse hubnet-enter-message?
    [ create-new-student ]
    [
      ifelse hubnet-exit-message?
      [ remove-student ]
      [ execute-command hubnet-message-tag ]
    ]
  ]
end 

to execute-command [command]
  if member? "Move to" command
  [
    ask students with [user-id = hubnet-message-source]
    [
      move-to-line ((read-from-string last command) - 1)
      hubnet-send user-id "Instructions:" "Wait in Line"
    ]
    stop
  ]

  if command = "vend"
  [
    ask students with [user-id = hubnet-message-source]
    [
      ifelse line-position = 1
      [
        ;; since vending machines are the first four turtles, their who is the line-number
        ask turtle line-number [vend myself]
        move-to-line line-number
        hubnet-send user-id "Instructions:" "Wait in Line"
      ]
      [
        hubnet-send user-id "Instructions:" "Wait for your turn"
      ]
    ]
  ]
end 

;; Create a student, set its shape and color, put it in a line
;; and tell the node about itself

to create-new-student
  create-students 1
  [
    setup-student-vars
    add-student-to-line self (who mod 4)
    hubnet-send user-id "Instructions:" "Wait in Line"
    send-info-to-clients
  ]
end 

;; Remove the student from her line and kill her

to remove-student
  ask students with [user-id = hubnet-message-source]
  [
    leave-line
    set used-shape-colors remove my-code used-shape-colors
    die
  ]
end 


;; sets the turtle variables to appropriate initial values

to setup-student-vars  ;; turtle procedure
    set user-id hubnet-message-source
    set-unique-shape-and-color
    set heading 0
    set money-spent 0
    set num-prizes 0
    set size 1.75
    set line-number (who mod 4)
    setxy (item line-number vend-positions) ( max-pycor - 2.5 - 2.2 * line-length line-number)
    set line-position line-length line-number
end 

;; sends the appropriate monitor information back to the client

to send-info-to-clients
  hubnet-send user-id "You are a:" (word (color-string color) " " shape)
  hubnet-send user-id "Money Spent:" money-spent
  hubnet-send user-id "Position In Line:" line-position
  hubnet-send user-id "Line Number:" line-number + 1
  hubnet-send user-id "Prizes Won:" num-prizes
  if money-spent != 0
    [hubnet-send user-id "Prizes Won vs. Money Spent:" (num-prizes / money-spent)]
end 

to set-unique-shape-and-color
  let code 0

  set code random max-possible-codes
  while [member? code used-shape-colors and count students < max-possible-codes]
  [
    set code random max-possible-codes
  ]
  set used-shape-colors (lput code used-shape-colors)
  set shape item (code mod length shape-names) shape-names
  set color item (code / length shape-names) colors
end 

;; translates a student turtle's shape and color into a code

to-report my-code
  report (position shape shape-names) + (length shape-names) * (position color colors)
end 


;; report the string version of the turtle's color

to-report color-string [color-value]
  report item (position color-value colors) color-names
end 

There are 2 versions of this model.

Uploaded by When Description Download
Uri Wilensky about 9 years ago vending Download this version
Uri Wilensky about 9 years ago vending Download this version

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