;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; Emergent Innovation Networks ; Attempt at replication of model in ; Cowan, Robin, Nicolas Jonard & Jean-Benoit Zimmermann (2007) "Bilateral Collaboration and the Emergence of Innovation Networks", ; Management Science, 53(7) 1051-1067. ; This version (C) Christopher J Watts, 2011 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; extensions [array matrix] globals [ expected-returns probability-success total-credit structural-credit relational-credit created-knowledge a-outcome a-time a-dos ; degree of separation in alliance net via most likely path a-freq ; frequency of alliance attempts a-prob ; best probability of activating path to each node node-queue ; Used for dos calculations node-queue-start node-queue-length ordered-firms num-additions sum-additions mean-additions mean-knowledge prev-mean-knowledge num-alinks num-components max-component net-constraint clust-coeff assortativity net-density net-diameter mean-degree min-degree max-degree median-degree mean-cliquishness min-cliquishness max-cliquishness mean-dos min-dos max-dos mean-constraint min-constraint max-constraint mean-betweenness min-betweenness max-betweenness mean-closeness min-closeness max-closeness degree-centralization closeness-centralization ] breed [firms firm] undirected-link-breed [alinks alink] firms-own [ knowledge num-successes num-self-successes e-partners a-partners matched max-exp-ret ; Network related degree constraint cliquishness dos reach closeness betweenness component predecessors ] alinks-own [ ; time ; outcome ] ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; Initialisation to setup clear-all ask patches [set pcolor white] setup-firms set ordered-firms sort firms set expected-returns matrix:make-constant number-of-firms number-of-firms 0 set probability-success matrix:make-constant number-of-firms number-of-firms 0 set total-credit matrix:make-constant number-of-firms number-of-firms 0 set structural-credit matrix:make-constant number-of-firms number-of-firms 0 set relational-credit matrix:make-constant number-of-firms number-of-firms 0 set created-knowledge matrix:make-constant number-of-firms number-of-firms 0 set a-outcome matrix:make-constant number-of-firms number-of-firms 0 set a-time matrix:make-constant number-of-firms number-of-firms 0 set a-freq matrix:make-constant number-of-firms number-of-firms 0 set a-dos matrix:make-constant number-of-firms number-of-firms (number-of-firms + 1) set node-queue array:from-list n-values number-of-firms [nobody] set a-prob array:from-list n-values number-of-firms [nobody] set mean-additions 0 set num-additions 0 set sum-additions 0 set mean-knowledge 0 set prev-mean-knowledge 0 calc-metrics update-plots end to setup-firms create-firms number-of-firms [ set shape "circle" set knowledge array:from-list n-values number-of-knowledge-types [1 + random 2] ; What if continuous? set expected-returns array:from-list n-values number-of-firms [0] set num-successes 0 set num-self-successes 0 ] reposition-nodes-grid end ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; Iterations to go if ticks = number-of-time-steps [stop] tick ; calc expected returns from alliances calc-relational-credit calc-structural-credit calc-total-credit calc-probability-success calc-created-knowledge calc-expected-returns ; create matching calc-matching ; update outputs if (0 = ticks mod output-every) [ calc-wdos recreate-net calc-metrics update-plots if reposition-nodes [reposition-nodes-spring] ] end ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; to calc-relational-credit let ego-id 0 let alter-id 0 let last-outcome 0 foreach ordered-firms [ set ego-id [who] of ? foreach sublist ordered-firms ego-id (length ordered-firms) [ set alter-id [who] of ? set last-outcome matrix:get a-outcome ego-id alter-id matrix:set relational-credit ego-id alter-id (ifelse-value (0 = last-outcome) [0] [(discount-factor ^ (ticks - matrix:get a-time ego-id alter-id)) * last-outcome]) matrix:set relational-credit alter-id ego-id (matrix:get relational-credit ego-id alter-id) ] ] end to calc-structural-credit let ego-id 0 let alter-id 0 let tertius 0 let sc-sum 0 foreach ordered-firms [ set ego-id [who] of ? foreach sublist ordered-firms ego-id (length ordered-firms) [ set alter-id [who] of ? set sc-sum 0 foreach ordered-firms [ set tertius [who] of ? if ego-id != tertius [ if alter-id != tertius [ set sc-sum sc-sum + ((matrix:get relational-credit ego-id tertius) * (matrix:get relational-credit tertius alter-id)) ] ] ] matrix:set structural-credit ego-id alter-id sc-sum matrix:set structural-credit alter-id ego-id sc-sum ] ] end to calc-total-credit let ego-id 0 let alter-id 0 let o-sum 0 foreach ordered-firms [ set ego-id [who] of ? set o-sum (sum matrix:get-row a-outcome ego-id) - (matrix:get a-outcome ego-id ego-id) foreach ordered-firms [ set alter-id [who] of ? ifelse o-sum = 0 [ matrix:set total-credit ego-id alter-id 0 ] [ matrix:set total-credit ego-id alter-id ((alpha * (matrix:get relational-credit ego-id alter-id) ) + ((1 - alpha) * (matrix:get structural-credit ego-id alter-id) / o-sum)) ] ] ] end to calc-probability-success let ego-id 0 let alter-id 0 let prob-range (max-probability-success - min-probability-success) foreach ordered-firms [ set ego-id [who] of ? foreach ordered-firms [ set alter-id [who] of ? matrix:set probability-success ego-id alter-id (min-probability-success + (prob-range * (matrix:get total-credit ego-id alter-id))) ] ] end to calc-created-knowledge let ego-id 0 let ego nobody let alter-id 0 let sum-total 0 let k-element 0 foreach ordered-firms [ set ego-id [who] of ? set ego ? foreach sublist ordered-firms ego-id (length ordered-firms) [ set alter-id [who] of ? set sum-total 0 set k-element 0 repeat number-of-knowledge-types [ set sum-total sum-total + ((knowledge-element ego ? k-element) ^ K-Type-Substitution) set k-element k-element + 1 ] matrix:set created-knowledge ego-id alter-id (k-production-scale * (sum-total ^ (1 / K-Type-Substitution))) matrix:set created-knowledge alter-id ego-id (matrix:get created-knowledge ego-id alter-id) ] ] end to-report knowledge-element [ego alter k-element] let ego-val [array:item knowledge k-element] of ego let alter-val [array:item knowledge k-element] of alter report ifelse-value (ego-val < alter-val) [ (((1 - theta) * ego-val) + (theta * alter-val)) ] [ (((1 - theta) * alter-val) + (theta * ego-val)) ] end to calc-expected-returns let ego-id 0 let alter 0 foreach ordered-firms [ set ego-id [who] of ? foreach ordered-firms [ set alter [who] of ? matrix:set expected-returns ego-id alter (matrix:get probability-success ego-id alter) * (matrix:get created-knowledge ego-id alter) ] ] end ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; to calc-matching let ego nobody let alter nobody let unmatched-firms map [?] ordered-firms set num-additions 0 set sum-additions 0 let evaluator-id 0 ask firms [ set matched false set e-partners [] set a-partners [] ] ask firms [ set evaluator-id who ; set max-exp-ret max matrix:get-row expected-returns evaluator-id set max-exp-ret -1 foreach unmatched-firms [ if max-exp-ret <= [matrix:get expected-returns evaluator-id who] of ? [ ifelse max-exp-ret < [matrix:get expected-returns evaluator-id who] of ? [ set max-exp-ret [matrix:get expected-returns evaluator-id who] of ? set e-partners (list ?) ] [ set e-partners fput ? e-partners ] ] ] ] ask firms [ foreach e-partners [ ask ? [set a-partners fput myself a-partners] ] ] let num-matched 0 while [num-matched < number-of-firms] [ set ego max-one-of (firms with [not matched]) [max-exp-ret] set alter [first e-partners] of ego ask ego [set matched true] set unmatched-firms remove ego unmatched-firms ifelse ego = alter [ set num-matched num-matched + 1 ] [ ask alter [set matched true] set unmatched-firms remove alter unmatched-firms set num-matched num-matched + 2 ] attempt-innovation ego alter ask ego [ foreach a-partners [ ask ? [ if not matched [ set e-partners remove myself e-partners if 0 = length e-partners [ set evaluator-id who set max-exp-ret -1 foreach unmatched-firms [ if [not matched] of ? [ if max-exp-ret <= [matrix:get expected-returns evaluator-id who] of ? [ ifelse max-exp-ret < [matrix:get expected-returns evaluator-id who] of ? [ set max-exp-ret [matrix:get expected-returns evaluator-id who] of ? set e-partners (list ?) ] [ set e-partners fput ? e-partners ] ] ] ] foreach e-partners [ ask ? [ set a-partners fput myself a-partners ] ] ] ] ] ] ] ask alter [ foreach a-partners [ ask ? [ if not matched [ set e-partners remove myself e-partners if 0 = length e-partners [ set evaluator-id who set max-exp-ret -1 foreach unmatched-firms [ if [not matched] of ? [ if max-exp-ret <= [matrix:get expected-returns evaluator-id who] of ? [ ifelse max-exp-ret < [matrix:get expected-returns evaluator-id who] of ? [ set max-exp-ret [matrix:get expected-returns evaluator-id who] of ? set e-partners (list ?) ] [ set e-partners fput ? e-partners ] ] ] ] foreach e-partners [ ask ? [ set a-partners fput myself a-partners ] ] ] ] ] ] ] ] if num-additions > 0 [ set mean-additions sum-additions / num-additions ] end to calc-matching-alt let ego nobody let alter nobody let evaluator-id 0 let possible-pairings [] let current-pairing array:from-list (list nobody nobody 0) let best-exp-ret 0 set num-additions 0 set sum-additions 0 foreach ordered-firms [ set ego ? set evaluator-id [who] of ? ;ask ego [set matched false] foreach ordered-firms [ set possible-pairings fput (array:from-list (list ego ? ([matrix:get expected-returns evaluator-id who] of ?))) possible-pairings ] ] let num-matched 0 while [num-matched < number-of-firms] [ set best-exp-ret max map [array:item ? 2] possible-pairings set current-pairing one-of filter [best-exp-ret = array:item ? 2] possible-pairings set ego array:item current-pairing 0 set alter array:item current-pairing 1 ask ego [set matched true] ifelse ego = alter [ set num-matched num-matched + 1 ] [ ask alter [set matched true] set num-matched num-matched + 2 ] attempt-innovation ego alter set possible-pairings filter [not ((member? ego (array:to-list ?)) or (member? alter (array:to-list ?)))] possible-pairings ] if num-additions > 0 [ set mean-additions sum-additions / num-additions ] end to calc-matching-old set num-additions 0 set sum-additions 0 let evaluator-id 0 ask firms [ set matched false set evaluator-id who set e-partners sort-by [([matrix:get expected-returns evaluator-id who] of ?1) > ([matrix:get expected-returns evaluator-id who] of ?2)] firms ] let ego nobody let alter nobody let num-matched 0 while [num-matched < number-of-firms] [ ask firms with [not matched] [ while [ifelse-value (0 < length e-partners) [[matched] of first e-partners] [false]] [ set e-partners but-first e-partners ] ] set ego max-one-of (firms with [not matched]) [matrix:get expected-returns who ([who] of first e-partners)] set alter [first e-partners] of ego ask ego [set matched true] ifelse ego = alter [ set num-matched num-matched + 1 ] [ ask alter [set matched true] set num-matched num-matched + 2 ] attempt-innovation ego alter ] if num-additions > 0 [ set mean-additions sum-additions / num-additions ] end to attempt-innovation [ego alter] let ego-id [who] of ego let alter-id [who] of alter let prob-s 0 matrix:set a-freq ego-id alter-id (1 + matrix:get a-freq ego-id alter-id) ; Should we count only alliances with innov. successes? matrix:set a-freq alter-id ego-id (matrix:get a-freq ego-id alter-id) ifelse ego = alter [ set prob-s max-probability-success ] [ set prob-s (matrix:get probability-success ego-id alter-id) ] ifelse (random-float 1) < prob-s [ ; Success! matrix:set a-outcome ego-id alter-id 1 matrix:set a-outcome alter-id ego-id 1 matrix:set a-time ego-id alter-id ticks matrix:set a-time alter-id ego-id ticks let weights [] let cur-element -1 repeat number-of-knowledge-types [ set cur-element cur-element + 1 set weights fput (knowledge-element ego alter cur-element) weights ] let weight-sum random-float sum weights set cur-element number-of-knowledge-types while [weight-sum >= 0] [ set cur-element cur-element - 1 set weight-sum weight-sum - first weights set weights but-first weights ] let k-addition (matrix:get created-knowledge ego-id alter-id) ask ego [ ; Is knowledge supposed to be bounded or unbounded? continuous or discrete? Paper was unclear! ; array:set knowledge cur-element (ifelse-value (k-addition + (array:item knowledge cur-element) <= 2) [k-addition + (array:item knowledge cur-element)] [2]) array:set knowledge cur-element (k-addition + (array:item knowledge cur-element)) if ego = alter [ set num-self-successes num-self-successes + 1 ] set num-successes num-successes + 1 ] ask alter [ ; array:set knowledge cur-element (ifelse-value (k-addition + (array:item knowledge cur-element) <= 2) [k-addition + (array:item knowledge cur-element)] [2]) array:set knowledge cur-element (k-addition + (array:item knowledge cur-element)) if ego != alter [ set num-successes num-successes + 1 ] ] ; print (word ego ", " alter ", 1, " cur-element ", " k-addition) set num-additions num-additions + 1 set sum-additions sum-additions + k-addition ] [ ; Failure! matrix:set a-outcome ego-id alter-id 0 matrix:set a-outcome alter-id ego-id 0 matrix:set a-time ego-id alter-id ticks matrix:set a-time alter-id ego-id ticks ] end ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; to calc-wdos ; Calculate degrees of separation in a weighted network set a-dos matrix:make-constant number-of-firms number-of-firms (number-of-firms + 1) let cur-node nobody let cur-id 0 let cur-prob 0 let cur-dos 0 let cur-rowsum 0 ; let cur-list (list nobody 1 0) let alt-prob 0 ask firms [ ; let start-node self let start-id who set a-prob array:from-list n-values number-of-firms [-1] set node-queue-start 0 array:set node-queue 0 (list self 1 0) set node-queue-length node-queue-length + 1 while [node-queue-length > 0] [ set cur-node item 0 (array:item node-queue node-queue-start) set cur-prob item 1 (array:item node-queue node-queue-start) set cur-dos item 2 (array:item node-queue node-queue-start) set cur-id [who] of cur-node matrix:set a-dos start-id cur-id cur-dos set node-queue-start (node-queue-start + 1) mod number-of-firms set node-queue-length node-queue-length - 1 set cur-rowsum sum matrix:get-row a-freq cur-id if cur-rowsum > 0 [ ask other firms with [0 < matrix:get a-freq cur-id who] [ set alt-prob (cur-prob * matrix:get a-freq cur-id who) / cur-rowsum if alt-prob > (array:item a-prob who) [ array:set a-prob who alt-prob array:set node-queue ((node-queue-start + node-queue-length) mod number-of-firms) (list self (alt-prob) (cur-dos + 1)) set node-queue-length node-queue-length + 1 ] ] ] ] ] end to recreate-net ;ask alinks [ die ] let ego-id 0 let alter-id 0 let ego nobody let alter nobody foreach ordered-firms [ set ego ? set ego-id [who] of ? foreach ordered-firms [ if ? != ego [ set alter ? set alter-id [who] of ? ; ifelse 1 = matrix:get a-outcome ego-id alter-id [ ; ifelse 0 < matrix:get a-freq ego-id alter-id [ ifelse 1 = matrix:get a-dos ego-id alter-id [ ask ego [ if not alink-neighbor? alter [ create-alink-with alter [ set color grey ] ] ] ] [ ask ego [ if alink-neighbor? alter [ ask alink-with alter [ die ] ] ] ] ] ] ] end ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; Networks ;; Repositioning an already created network to reposition-nodes-spring ;layout-spring turtle-set link-set spring-constant spring-length repulsion-constant repeat 10 [layout-spring firms alinks 0.2 (1.5 * max-pxcor / (sqrt count firms)) 1] end to reposition-nodes-circle layout-circle (sort firms) (max-pxcor * 0.4) end to reposition-nodes-grid let numnodes (count firms) let numcols int sqrt numnodes if (numcols ^ 2) < numnodes [set numcols numcols + 1] let numrows int (numnodes / numcols) if (numcols * numrows) < numnodes [set numrows numrows + 1] let xspace (max-pxcor / (numcols + 1)) let yspace (max-pycor / (numrows + 1)) let orderedset sort firms foreach orderedset [ ask ? [ set xcor (xspace * (1 + (who mod numcols))) set ycor (yspace * (1 + int (who / numcols))) ] ] end ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; Calculate various node and network metrics to calc-metrics calc-degree calc-components set net-density (2 * (count alinks) / ((count firms) * ((count firms) - 1))) ifelse calculate-slow-metrics [ calc-net-constraint calc-cliquishness calc-assortativity calc-betweenness ] [ calc-cliquishness calc-dos ] end to calc-degree ; Degree centrality = # links ask firms [ set degree (count my-alinks) ] set mean-degree mean [degree] of firms set min-degree min [degree] of firms set max-degree max [degree] of firms set median-degree median [degree] of firms end to calc-net-constraint let csum 0 let cij 0 ask firms [ let degi (count my-alinks) let origin self set csum 0 ask alink-neighbors [ ; direct or (direct and indirect) set cij (1 / degi) let dest self ask [alink-neighbors] of origin [ if (alink-neighbor? dest) [ set cij (cij + (1 / (degi * (count my-alinks)))) ] ] set csum (csum + (cij ^ 2)) ] set constraint csum ] set net-constraint sum [constraint] of firms set mean-constraint mean [constraint] of firms set min-constraint min [constraint] of firms set max-constraint max [constraint] of firms end to calc-cliquishness ; Node cliquishness = proportion of 2-stars that are triangles ; Clustering coefficient: what proportion of triplets are in fact triangles let origin nobody let num-triangles 0 let num-2stars 0 let tot-num-triangles 0 let tot-num-2stars 0 let temp-neighbors nobody ask firms [ set num-triangles 0 set num-2stars 0 ; cliquishness = proportion of 2-stars that are triangles set temp-neighbors alink-neighbors ask temp-neighbors [ set origin self ask temp-neighbors [ if alink-neighbor? origin [ if (origin != self) [ set num-triangles num-triangles + 1 ] ] ] ] set num-2stars (count alink-neighbors) * ((count alink-neighbors) - 1) ifelse (num-2stars = 0) [ set cliquishness 0 ] [ set cliquishness (num-triangles / num-2stars) ] set tot-num-triangles tot-num-triangles + num-triangles set tot-num-2stars tot-num-2stars + num-2stars ] set mean-cliquishness mean [cliquishness] of firms set min-cliquishness min [cliquishness] of firms set max-cliquishness max [cliquishness] of firms if tot-num-2stars > 0 [ set clust-coeff tot-num-triangles / tot-num-2stars ] end to calc-assortativity let avg1 0 let avg2 0 let sum1 0 let sum2 0 let sum3 0 ask firms [ set sum1 sum1 + ((count alink-neighbors) * degree) set sum3 sum3 + (count alink-neighbors) ask alink-neighbors [ set sum2 sum2 + degree ] ] ifelse (sum3 > 0) [ set avg1 sum1 / sum3 set avg2 sum2 / sum3 set sum1 0 set sum2 0 set sum3 0 let temp-diff 0 ask firms [ set temp-diff (degree - avg1) set sum2 sum2 + ((count alink-neighbors) * (temp-diff ^ 2)) ask alink-neighbors [ set sum1 sum1 + (temp-diff * (degree - avg2)) set sum3 sum3 + ((degree - avg2) ^ 2) ] ] ifelse sum2 * sum3 > 0 [ set assortativity sum1 / (sqrt (sum2 * sum3)) ] [ set assortativity 0 ] ] [ set assortativity 0 ] end to calc-betweenness ; Ulrik Brandes's betweenness algorithm ; let CB array:from-list n-values (count firms) [0] let S [] ; Stack (LIFO) let Q [] ; Queue (FIFO) let R array:from-list n-values (count firms) [0] ; # paths let d array:from-list n-values (count firms) [0] ; distance ;let P array:from-list n-values (count firms) [0] ; Predecessor list let dep array:from-list n-values (count firms) [0] let v nobody let v-who 0 let w nobody let w-who 0 let maxdos 0 ; let denominator (((count firms) - 1) * ((count firms) - 2) / 2) let denominator ((count firms) - 1) * ((count firms) - 2) set net-diameter -1 ask firms [ set S [] ask firms [ set predecessors [] ] ;set P [] set R array:from-list n-values (count firms) [0] array:set R who 1 set d array:from-list n-values (count firms) [-1] array:set d who 0 set Q [] set Q lput self Q while [length Q > 0] [ set v first Q set Q but-first Q set S fput v S set v-who [who] of v ask [alink-neighbors] of v [ if (array:item d who) < 0 [ set Q lput self Q array:set d who (1 + array:item d v-who) ] if (array:item d who) = (1 + array:item d v-who) [ array:set R who ((array:item R who) + (array:item R v-who)) set predecessors fput v predecessors ;set P fput v P ] ] ] set dep array:from-list n-values (count firms) [0] while [(length S) > 0] [ set w first S set S but-first S set w-who [who] of w foreach [predecessors] of w [ ask ? [ array:set dep who (array:item dep who) + (((array:item R who) / (array:item R w-who)) * (1 + array:item dep w-who)) ] ] if w != self [ array:set CB w-who ((array:item CB w-who) + (array:item dep w-who)) ] ] set reach sum map [ifelse-value (? >= 0) [1] [0]] (array:to-list d) set dos (sum (array:to-list d)) / reach set closeness ifelse-value (dos <= 0) [-1] [(reach - 1) / (dos * reach)] set maxdos max (array:to-list d) if (maxdos > net-diameter) [ set net-diameter maxdos ] ] ask firms [ set betweenness (array:item CB who) / denominator ] set mean-dos mean [dos] of firms set min-dos min [dos] of firms set max-dos max [dos] of firms set mean-closeness mean [closeness] of firms set min-closeness min [closeness] of firms set max-closeness max [closeness] of firms set mean-betweenness mean [betweenness] of firms set min-betweenness min [betweenness] of firms set max-betweenness max [betweenness] of firms set degree-centralization number-of-firms * (max-degree - mean-degree) / ((number-of-firms - 1) * (number-of-firms - 2)) set closeness-centralization number-of-firms * (max-closeness - mean-closeness) * (2 * number-of-firms - 3) / ((number-of-firms - 1) * (number-of-firms - 2)) end to calc-dos ; From Ulrik Brandes's betweenness algorithm ; let Q [] ; Queue (FIFO) let d array:from-list n-values (count firms) [0] ; distance let v nobody let v-who 0 let maxdos 0 set net-diameter -1 ask firms [ set d array:from-list n-values (count firms) [-1] array:set d who 0 set Q [] set Q lput self Q while [length Q > 0] [ set v first Q set Q but-first Q set v-who [who] of v ask [alink-neighbors] of v [ if (array:item d who) < 0 [ set Q lput self Q array:set d who (1 + array:item d v-who) ] ] ] set reach sum map [ifelse-value (? >= 0) [1] [0]] (array:to-list d) set dos (sum (array:to-list d)) / reach set closeness ifelse-value (dos <= 0) [0] [(reach - 1) / (dos * reach)] set maxdos max (array:to-list d) if (maxdos > net-diameter) [ set net-diameter maxdos ] ] set mean-dos mean [dos] of firms; with [dos >= 0] set min-dos min [dos] of firms; with [dos >= 0] set max-dos max [dos] of firms; with [dos >= 0] set mean-closeness mean [closeness] of firms set min-closeness min [closeness] of firms set max-closeness max [closeness] of firms set degree-centralization number-of-firms * (max-degree - mean-degree) / ((number-of-firms - 1) * (number-of-firms - 2)) set closeness-centralization number-of-firms * (max-closeness - mean-closeness) * (2 * number-of-firms - 3) / ((number-of-firms - 1) * (number-of-firms - 2)) end ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; to calc-components ; Calculate a network component for each node, and the size of the largest component let nodestack [] let tempnode nobody let num-members 0 set num-components 0 set max-component 0 ask firms [ set component 0] ask firms [ if (component = 0) [ set nodestack [] set num-components num-components + 1 if (num-members > max-component) [set max-component num-members] set num-members 1 set component num-components ask alink-neighbors with [component = 0] [ set nodestack fput self nodestack ] while [not empty? nodestack] [ set tempnode first nodestack set nodestack but-first nodestack ask tempnode [ if (component = 0) [ set component num-components set num-members num-members + 1 ask alink-neighbors with [component = 0] [ set nodestack fput self nodestack ] ] ] ] ] ] if (num-members > max-component) [set max-component num-members] end ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; Plots to update-plots set-current-plot "Innovation Production" plotxy ticks mean-additions set-current-plot "Knowledge" set prev-mean-knowledge mean-knowledge set mean-knowledge mean [mean array:to-list knowledge] of firms plotxy ticks mean-knowledge set-current-plot "Knowledge Growth" plotxy ticks ifelse-value (prev-mean-knowledge = 0) [0] [100 * (((mean-knowledge / prev-mean-knowledge) ^ (1 / output-every)) - 1)] set-current-plot "Density" plotxy ticks net-density set-current-plot "Components" set-current-plot-pen "# Components" plotxy ticks num-components set-current-plot-pen "Largest" plotxy ticks max-component set-current-plot "Clustering Coefficient" plotxy ticks clust-coeff set-current-plot "Degree of Connectivity" set-current-plot-pen "Mean" plotxy ticks mean-degree set-current-plot-pen "Min" plotxy ticks min-degree set-current-plot-pen "Max" plotxy ticks max-degree set-current-plot "Degree of Separation" set-current-plot-pen "Mean" plotxy ticks mean-dos set-current-plot-pen "Min" plotxy ticks min-dos set-current-plot-pen "Max" plotxy ticks max-dos end to print-knowledge foreach sort firms [ ask ? [ show (array:to-list knowledge) ] ] end to toggle-labels ask firms [ ifelse label = "" [ set label who ] [ set label "" ] ] end @#$#@#$#@ GRAPHICS-WINDOW 210 10 649 470 -1 -1 13.0 1 10 1 1 1 0 0 0 1 0 32 0 32 0 0 1 ticks TEXTBOX 6 6 156 58 Innovation Networks 21 0.0 1 TEXTBOX 6 64 156 82 After: Cowan Et Al (2007) 11 0.0 1 INPUTBOX 6 86 161 146 Number-of-Firms 100 1 0 Number SLIDER 6 148 207 181 Number-of-Knowledge-Types Number-of-Knowledge-Types 2 10 5 1 1 NIL HORIZONTAL SLIDER 6 249 178 282 Theta Theta 0 1 0.8 .01 1 NIL HORIZONTAL SLIDER 5 200 177 233 Alpha Alpha 0 1 0.1 0.01 1 NIL HORIZONTAL INPUTBOX 6 285 161 345 K-Production-Scale 1.0E-8 1 0 Number INPUTBOX 6 348 161 408 K-Type-Substitution 0.1 1 0 Number INPUTBOX 6 411 161 471 Discount-Factor 0.98 1 0 Number SLIDER 6 474 190 507 Min-Probability-Success Min-Probability-Success 0 1 0.75 .01 1 NIL HORIZONTAL SLIDER 6 510 190 543 Max-Probability-Success Max-Probability-Success 0 1 0.95 .01 1 NIL HORIZONTAL INPUTBOX 210 473 365 533 Number-of-Time-Steps 200 1 0 Number BUTTON 367 473 431 506 Setup setup NIL 1 T OBSERVER NIL NIL NIL NIL BUTTON 434 473 497 506 Go go T 1 T OBSERVER NIL NIL NIL NIL SWITCH 210 537 390 570 Calculate-Slow-Metrics Calculate-Slow-Metrics 1 1 -1000 BUTTON 500 473 579 506 Go Once go NIL 1 T OBSERVER NIL NIL NIL NIL BUTTON 584 474 650 507 Spring reposition-nodes-spring T 1 T OBSERVER NIL NIL NIL NIL MONITOR 660 10 717 55 Density net-density 4 1 11 MONITOR 720 10 815 55 # Components num-components 17 1 11 MONITOR 819 10 940 55 Largest Component max-component 17 1 11 PLOT 660 64 860 214 Density Time (ticks) Density 0.0 1.0 0.0 0.01 true false PENS "default" 1.0 0 -16777216 true PLOT 660 221 968 371 Components Time (ticks) # Nodes 0.0 1.0 0.0 1.0 true true PENS "# Components" 1.0 0 -2674135 true "Largest" 1.0 0 -13345367 true PLOT 661 603 970 753 Degree of Separation Time (ticks) DOS 0.0 1.0 0.0 1.0 true true PENS "Mean" 1.0 0 -2674135 true "Min" 1.0 0 -11221820 true "Max" 1.0 0 -13345367 true PLOT 971 221 1171 371 Clustering Coefficient Time (ticks) Clust. Coeff. 0.0 1.0 0.0 1.0 true false PENS "default" 1.0 0 -16777216 true PLOT 864 64 1088 214 Degree of Connectivity Time (ticks) # Links 0.0 1.0 0.0 1.0 true true PENS "Mean" 1.0 0 -2674135 true "Min" 1.0 0 -11221820 true "Max" 1.0 0 -13345367 true SWITCH 391 537 543 570 Reposition-Nodes Reposition-Nodes 0 1 -1000 MONITOR 943 10 1076 55 Degree Centralization degree-centralization 3 1 11 MONITOR 660 530 752 575 # Innovations num-additions 17 1 11 MONITOR 754 530 860 575 Mean Innovation mean-additions 3 1 11 PLOT 660 373 860 523 Innovation Production Time (ticks) Mean Additions 0.0 1.0 0.0 0.01 true false PENS "default" 1.0 0 -16777216 true TEXTBOX 6 236 156 254 Knowledge Task Structure: 11 0.0 1 TEXTBOX 6 186 205 204 Relational vs. Structural Embedding: 11 0.0 1 INPUTBOX 8 604 163 664 Output-Every 1 1 0 Number BUTTON 210 579 330 612 Print Knowledge print-knowledge NIL 1 T OBSERVER NIL NIL NIL NIL TEXTBOX 662 588 984 606 (Not very meaningful unless all nodes in one component.) 11 0.0 1 BUTTON 390 579 494 612 Labels on/off toggle-labels NIL 1 T OBSERVER NIL NIL NIL NIL MONITOR 1079 10 1187 55 Clustering Coeff. clust-coeff 3 1 11 MONITOR 862 530 968 575 Mean Knowledge mean-knowledge 3 1 11 MONITOR 970 530 1073 575 Mean % Growth 100 * (((mean-knowledge / prev-mean-knowledge) ^ (1 / output-every)) - 1) 1 1 11 PLOT 862 373 1062 523 Knowledge Time (ticks) Type Mean 0.0 1.0 0.0 1.0 true false PENS "default" 1.0 0 -16777216 true PLOT 1065 373 1265 523 Knowledge Growth Time (ticks) % Growth 0.0 1.0 0.0 100.0 true false PENS "default" 1.0 0 -16777216 true @#$#@#$#@ WHAT IS IT? ----------- A Model of Emergent Innovation Networks An attempt at replicating the model described in Cowan et al (2007). HOW IT WORKS ------------ HOW TO USE IT ------------- THINGS TO NOTICE ---------------- THINGS TO TRY ------------- EXTENDING THE MODEL ------------------- NETLOGO FEATURES ---------------- RELATED MODELS -------------- For an alternative simulation of innovation networks, see the SKIN model. CREDITS AND REFERENCES ---------------------- Cowan, Robin, Nicolas Jonard & Jean-Benoit Zimmermann (2007) "Bilateral Collaboration and the Emergence of Innovation Networks", Management Science, 53(7) 1051-1067. @#$#@#$#@ default true 0 Polygon -7500403 true true 150 5 40 250 150 205 260 250 airplane true 0 Polygon -7500403 true true 150 0 135 15 120 60 120 105 15 165 15 195 120 180 135 240 105 270 120 285 150 270 180 285 210 270 165 240 180 180 285 195 285 165 180 105 180 60 165 15 arrow true 0 Polygon -7500403 true true 150 0 0 150 105 150 105 293 195 293 195 150 300 150 box false 0 Polygon -7500403 true true 150 285 285 225 285 75 150 135 Polygon -7500403 true true 150 135 15 75 150 15 285 75 Polygon -7500403 true true 15 75 15 225 150 285 150 135 Line -16777216 false 150 285 150 135 Line -16777216 false 150 135 15 75 Line -16777216 false 150 135 285 75 bug true 0 Circle -7500403 true true 96 182 108 Circle -7500403 true true 110 127 80 Circle -7500403 true true 110 75 80 Line -7500403 true 150 100 80 30 Line -7500403 true 150 100 220 30 butterfly true 0 Polygon -7500403 true true 150 165 209 199 225 225 225 255 195 270 165 255 150 240 Polygon -7500403 true true 150 165 89 198 75 225 75 255 105 270 135 255 150 240 Polygon -7500403 true true 139 148 100 105 55 90 25 90 10 105 10 135 25 180 40 195 85 194 139 163 Polygon -7500403 true true 162 150 200 105 245 90 275 90 290 105 290 135 275 180 260 195 215 195 162 165 Polygon -16777216 true false 150 255 135 225 120 150 135 120 150 105 165 120 180 150 165 225 Circle -16777216 true false 135 90 30 Line -16777216 false 150 105 195 60 Line -16777216 false 150 105 105 60 car false 0 Polygon -7500403 true true 300 180 279 164 261 144 240 135 226 132 213 106 203 84 185 63 159 50 135 50 75 60 0 150 0 165 0 225 300 225 300 180 Circle -16777216 true false 180 180 90 Circle -16777216 true false 30 180 90 Polygon -16777216 true false 162 80 132 78 134 135 209 135 194 105 189 96 180 89 Circle -7500403 true true 47 195 58 Circle -7500403 true true 195 195 58 circle false 0 Circle -7500403 true true 0 0 300 circle 2 false 0 Circle -7500403 true true 0 0 300 Circle -16777216 true false 30 30 240 cow false 0 Polygon -7500403 true true 200 193 197 249 179 249 177 196 166 187 140 189 93 191 78 179 72 211 49 209 48 181 37 149 25 120 25 89 45 72 103 84 179 75 198 76 252 64 272 81 293 103 285 121 255 121 242 118 224 167 Polygon -7500403 true true 73 210 86 251 62 249 48 208 Polygon -7500403 true true 25 114 16 195 9 204 23 213 25 200 39 123 cylinder false 0 Circle -7500403 true true 0 0 300 dot false 0 Circle -7500403 true true 90 90 120 face happy false 0 Circle -7500403 true true 8 8 285 Circle -16777216 true false 60 75 60 Circle -16777216 true false 180 75 60 Polygon -16777216 true false 150 255 90 239 62 213 47 191 67 179 90 203 109 218 150 225 192 218 210 203 227 181 251 194 236 217 212 240 face neutral false 0 Circle -7500403 true true 8 7 285 Circle -16777216 true false 60 75 60 Circle -16777216 true false 180 75 60 Rectangle -16777216 true false 60 195 240 225 face sad false 0 Circle -7500403 true true 8 8 285 Circle -16777216 true false 60 75 60 Circle -16777216 true false 180 75 60 Polygon -16777216 true false 150 168 90 184 62 210 47 232 67 244 90 220 109 205 150 198 192 205 210 220 227 242 251 229 236 206 212 183 fish false 0 Polygon -1 true false 44 131 21 87 15 86 0 120 15 150 0 180 13 214 20 212 45 166 Polygon -1 true false 135 195 119 235 95 218 76 210 46 204 60 165 Polygon -1 true false 75 45 83 77 71 103 86 114 166 78 135 60 Polygon -7500403 true true 30 136 151 77 226 81 280 119 292 146 292 160 287 170 270 195 195 210 151 212 30 166 Circle -16777216 true false 215 106 30 flag false 0 Rectangle -7500403 true true 60 15 75 300 Polygon -7500403 true true 90 150 270 90 90 30 Line -7500403 true 75 135 90 135 Line -7500403 true 75 45 90 45 flower false 0 Polygon -10899396 true false 135 120 165 165 180 210 180 240 150 300 165 300 195 240 195 195 165 135 Circle -7500403 true true 85 132 38 Circle -7500403 true true 130 147 38 Circle -7500403 true true 192 85 38 Circle -7500403 true true 85 40 38 Circle -7500403 true true 177 40 38 Circle -7500403 true true 177 132 38 Circle -7500403 true true 70 85 38 Circle -7500403 true true 130 25 38 Circle -7500403 true true 96 51 108 Circle -16777216 true false 113 68 74 Polygon -10899396 true false 189 233 219 188 249 173 279 188 234 218 Polygon -10899396 true false 180 255 150 210 105 210 75 240 135 240 house false 0 Rectangle -7500403 true true 45 120 255 285 Rectangle -16777216 true false 120 210 180 285 Polygon -7500403 true true 15 120 150 15 285 120 Line -16777216 false 30 120 270 120 leaf false 0 Polygon -7500403 true true 150 210 135 195 120 210 60 210 30 195 60 180 60 165 15 135 30 120 15 105 40 104 45 90 60 90 90 105 105 120 120 120 105 60 120 60 135 30 150 15 165 30 180 60 195 60 180 120 195 120 210 105 240 90 255 90 263 104 285 105 270 120 285 135 240 165 240 180 270 195 240 210 180 210 165 195 Polygon -7500403 true true 135 195 135 240 120 255 105 255 105 285 135 285 165 240 165 195 line true 0 Line -7500403 true 150 0 150 300 line half true 0 Line -7500403 true 150 0 150 150 pentagon false 0 Polygon -7500403 true true 150 15 15 120 60 285 240 285 285 120 person false 0 Circle -7500403 true true 110 5 80 Polygon -7500403 true true 105 90 120 195 90 285 105 300 135 300 150 225 165 300 195 300 210 285 180 195 195 90 Rectangle -7500403 true true 127 79 172 94 Polygon -7500403 true true 195 90 240 150 225 180 165 105 Polygon -7500403 true true 105 90 60 150 75 180 135 105 plant false 0 Rectangle -7500403 true true 135 90 165 300 Polygon -7500403 true true 135 255 90 210 45 195 75 255 135 285 Polygon -7500403 true true 165 255 210 210 255 195 225 255 165 285 Polygon -7500403 true true 135 180 90 135 45 120 75 180 135 210 Polygon -7500403 true true 165 180 165 210 225 180 255 120 210 135 Polygon -7500403 true true 135 105 90 60 45 45 75 105 135 135 Polygon -7500403 true true 165 105 165 135 225 105 255 45 210 60 Polygon -7500403 true true 135 90 120 45 150 15 180 45 165 90 sheep false 0 Rectangle -7500403 true true 151 225 180 285 Rectangle -7500403 true true 47 225 75 285 Rectangle -7500403 true true 15 75 210 225 Circle -7500403 true true 135 75 150 Circle -16777216 true false 165 76 116 square false 0 Rectangle -7500403 true true 30 30 270 270 square 2 false 0 Rectangle -7500403 true true 30 30 270 270 Rectangle -16777216 true false 60 60 240 240 star false 0 Polygon -7500403 true true 151 1 185 108 298 108 207 175 242 282 151 216 59 282 94 175 3 108 116 108 target false 0 Circle -7500403 true true 0 0 300 Circle -16777216 true false 30 30 240 Circle -7500403 true true 60 60 180 Circle -16777216 true false 90 90 120 Circle -7500403 true true 120 120 60 tree false 0 Circle -7500403 true true 118 3 94 Rectangle -6459832 true false 120 195 180 300 Circle -7500403 true true 65 21 108 Circle -7500403 true true 116 41 127 Circle -7500403 true true 45 90 120 Circle -7500403 true true 104 74 152 triangle false 0 Polygon -7500403 true true 150 30 15 255 285 255 triangle 2 false 0 Polygon -7500403 true true 150 30 15 255 285 255 Polygon -16777216 true false 151 99 225 223 75 224 truck false 0 Rectangle -7500403 true true 4 45 195 187 Polygon -7500403 true true 296 193 296 150 259 134 244 104 208 104 207 194 Rectangle -1 true false 195 60 195 105 Polygon -16777216 true false 238 112 252 141 219 141 218 112 Circle -16777216 true false 234 174 42 Rectangle -7500403 true true 181 185 214 194 Circle -16777216 true false 144 174 42 Circle -16777216 true false 24 174 42 Circle -7500403 false true 24 174 42 Circle -7500403 false true 144 174 42 Circle -7500403 false true 234 174 42 turtle true 0 Polygon -10899396 true false 215 204 240 233 246 254 228 266 215 252 193 210 Polygon -10899396 true false 195 90 225 75 245 75 260 89 269 108 261 124 240 105 225 105 210 105 Polygon -10899396 true false 105 90 75 75 55 75 40 89 31 108 39 124 60 105 75 105 90 105 Polygon -10899396 true false 132 85 134 64 107 51 108 17 150 2 192 18 192 52 169 65 172 87 Polygon -10899396 true false 85 204 60 233 54 254 72 266 85 252 107 210 Polygon -7500403 true true 119 75 179 75 209 101 224 135 220 225 175 261 128 261 81 224 74 135 88 99 wheel false 0 Circle -7500403 true true 3 3 294 Circle -16777216 true false 30 30 240 Line -7500403 true 150 285 150 15 Line -7500403 true 15 150 285 150 Circle -7500403 true true 120 120 60 Line -7500403 true 216 40 79 269 Line -7500403 true 40 84 269 221 Line -7500403 true 40 216 269 79 Line -7500403 true 84 40 221 269 x false 0 Polygon -7500403 true true 270 75 225 30 30 225 75 270 Polygon -7500403 true true 30 75 75 30 270 225 225 270 @#$#@#$#@ NetLogo 4.1.3 @#$#@#$#@ @#$#@#$#@ @#$#@#$#@ setup go timer num-additions mean-additions max-component num-components net-density clust-coeff ifelse-value (net-density = 0) [0] [clust-coeff / net-density] net-diameter degree-centralization closeness-centralization mean-degree max-degree min-degree median-degree mean-dos max-dos min-dos mean-closeness max-closeness min-closeness setup go timer num-additions mean-additions max-component num-components net-density clust-coeff ifelse-value (net-density = 0) [0] [clust-coeff / net-density] net-diameter degree-centralization closeness-centralization mean-degree max-degree min-degree median-degree mean-dos max-dos min-dos mean-closeness max-closeness min-closeness @#$#@#$#@ @#$#@#$#@ default 0.0 -0.2 0 1.0 0.0 0.0 1 1.0 0.0 0.2 0 1.0 0.0 link direction true 0 Line -7500403 true 150 150 90 180 Line -7500403 true 150 150 210 180 @#$#@#$#@ 0 @#$#@#$#@