4.6 Trajectoires des individus au sein des paysages sémantiques
4.6.1 Opérateur de projection
Maintenant que nous avons défini une méthode pour représenter les paysages
scientifiques en spacialisant des réseaux de proximité entre champs ˆG, notre ob-
jectif est d’y “situer” également des chercheurs ou d’autres types d’entités, en pro- jetant leur bagage conceptuel sur les cartes produites. L’opérateur de projection que nous concevons est générique au sens où il doit permettre de projeter aussi bien des chercheurs, des institutions, des journaux, ou des conférences. En toute géné- ralité, il suffit d’attribuer à une entité un corpus défini par exemple par l’ensemble des articles auxquels elle est liée (les publications d’un chercheur, les articles pu- bliés dans une conférence ou dans un journal donné, etc.) et d’en extraire un bagage
conceptuelqui servira de signature de l’activité de cette entité au sein du domaine.
Dans la suite, même si la méthode s’applique plus largement sans difficulté, nous ne traiterons dans nos exemples que des corpus de publications signés par un chercheur.
On définit donc le bagage conceptuel Bi(T ) ∈ Nl (l = |L| désigne le nombre
nombre d’occurrences de chaque concept de L que i a mobilisé dans l’ensemble des publications dont il est l’auteur pendant la période T . Contrairement aux vec-
teurs Cj qui définissant les champs, le vecteur Bi(T )peut prendre des valeurs
supérieures à 1 si l’auteur i a publié plusieurs articles avec le même concept. Ainsi
la jmecoordonnées de B
i(T )est égale au nombre d’articles signés par i pendant la
période T mentionnant le concept j.
On souhaite maintenant définir l’opérateur de projection h : Nl → Rn( n dé-
signant le nombre de champs épistémiques reconstruits), qui, à un bagage séman- tique donné, fait correspondre un vecteur de probabilités d’appartenance à l’en-
semble des champs {Cj}1≤j≤n, la probabilité pi(Cj)que le chercheur i appartienne
à Cjpeut s’écrire à partir de la distance inter-cluster déjà définie section 4.4.5. Nous
proposons une définition plus générale de la distance inter-cluster précédemment définie de façon à ce qu’elle permette de prendre en compte des clusters définis
comme des vecteurs dans Nlprenant des valeurs entières pouvant être supérieures
à 1.Ainsi, la distance inter-cluster généralisée ˆSs’écrit sous la forme :
ˆ S(Ca, Cb) = 1 Pn k=1Ca(k)Pnk=1Cb(k) n X i,j=1 Ca(i)Cb(j)S(i, j)
Cette nouvelle définition laisse inchangée la mesure entre deux clusters et per-
met de définir la proximité ˆS(Bi(T ), Cj)entre le bagage sémantique de l’agent i
et un champ Cj au temps T . Le degré d’appartenance d’un agent i à un champ j
vaut alors : pT
i (Cj) = ˆS(Bi(T ), Cj)
On peut également normaliser cette dernière quantité afin d’obtenir un vecteur des probabilités de présence de i sur l’ensemble des champs :
ˆ pTi (Cj) = pT i (Cj) Pl k=1pTi (Ck) = Sˆ T(B i(T ), Cj) Pl k=1S(Bˆ i(T ), Ck)
Cette projection définit un vecteur de probabilité de présence ˆpi qui peut s’in-
terpréter comme une densité de présence d’un auteur sur l’ensemble des champs
scientifiques28. Nous avons représenté figure 4.23 l’évolution de la densité de pré-
sence d’un auteur choisi au hasard dans notre base de données. Philip Lowe est professeur d’économie rurale et directeur du programme d’économie rurale et
d’aménagement du territoire du Centre de l’université de Newcastle29. Cette re-
présentation a comme simple ambition d’illuster la façon dont notre opérateur per- met de situer un auteur au sein d’une “géographie” de la connaissance. Plusieurs observations peuvent être faites :
28. Cette normalisation n’est pas nécessairement souhaitable lorsqu’on compare la projection de différentes entités les unes avec les autres. Les distribution des degrés d’appartenance d’une entité aux champs d’un domaine peuvent être très différents d’une entité à l’autre, et il peut être souhai- table de conserver ces différences en abandonnant l’opération de normalisation.
9:agricultural research/agricultural development 11:food security/food production
17:development policy/economic development 18:floodplains/natural disasters
20:innovation adoption/diffusion of information 24:deforestation/trees
25:international agreements/international cooperation
28:drainage/reclamation 29:pest control/weeds
32:land management/landscape conservation 33:temperature/economic impact
37:grazing/grassland management
38:technical progress/innovation adoption 40:private ownership/property rights
41:transition economies/agricultural situation 42:forest economics/valuation
43:efficiency/farm inputs 44:drainage systems/water table
46:soil fertility/soil conservation 47:fishing/fishery policy
48:maps/remote sensing 49:land policy/public domain
50:population growth/population pressure 52:urbanization/agricultural land 53:cap/subsidies
55:renewable resources/fuel crops
56:precipitation/climate
57:community forestry/social participation
58:intellectual property rights/indigenous knowledge
59:floods/flooding 60:social impact/economic impact 63:refuse/waste water treatment
66:bioenergy/greenhouse gases
67:biotechnology/genetic engineering 68:catchment hydrology/runoff 69:production/exports
70:water use efficiency/trickle irrigation 71:sediment/soil conservation 72:runoff/groundwater 73:nitrates/pollution control 74:groundwater/irrigation water 75:fishery resources/fishing 76:mapping/maps 77:subsidies/support measures 78:trade liberalization/regulations 79:fuels/fuel crops 81:tourism impact/destinations 82:pastures/range management 83:wild animals/wildlife 84:refuse/waste treatment
86:land ownership/land policy 87:carbon sequestration/carbon dioxide
88:grasslands/botanical composition 89:indigenous knowledge/plant genetic resources
90:outdoor recreation/visitors
91:weed control/agricultural entomology
92:regulations/exports
94:low input agriculture/maize 95:irrigation systems/water use efficiency 96:forest policy/private forestry
97:satellite imagery/remote sensing 98:wildlife management/wild animals
99:tenure systems/land reform 100:polluted water/pollutants 101:bioremediation/risk assessment
102:polluted water/leaching
103:natural resource economics/resources 104:waste management/waste water
105:water allocation/irrigation water 106:carbon dioxide/carbon sequestration
107:species richness/botanical composition 108:forest policy/forest resources
109:tourist industry/destinations
110:tenure systems/land ownership
111:biology/agricultural entomology 112:control/plant pests
113:soyabeans/low input agriculture 114:forest policy/forest economics
115:economic theory/resource allocation 116:agricultural trade/world trade organization
119:waste utilization/refuse
120:world trade organization/trade liberalization
121:water policy/irrigation water
122:utilization/arid zones
9:agricultural research/agricultural development 11:food security/food production
17:development policy/economic development 18:floodplains/natural disasters
20:innovation adoption/diffusion of information 24:deforestation/trees
25:international agreements/international cooperation
28:drainage/reclamation 29:pest control/weeds
32:land management/landscape conservation 33:temperature/economic impact
37:grazing/grassland management
38:technical progress/innovation adoption 40:private ownership/property rights
41:transition economies/agricultural situation 42:forest economics/valuation
43:efficiency/farm inputs 44:drainage systems/water table 46:soil fertility/soil conservation 47:fishing/fishery policy
48:maps/remote sensing 49:land policy/public domain
50:population growth/population pressure 52:urbanization/agricultural land 53:cap/subsidies
55:renewable resources/fuel crops
56:precipitation/climate
57:community forestry/social participation
58:intellectual property rights/indigenous knowledge
59:floods/flooding 60:social impact/economic impact 63:refuse/waste water treatment
66:bioenergy/greenhouse gases
67:biotechnology/genetic engineering 68:catchment hydrology/runoff 69:production/exports
70:water use efficiency/trickle irrigation 71:sediment/soil conservation 72:runoff/groundwater 73:nitrates/pollution control 74:groundwater/irrigation water 75:fishery resources/fishing 76:mapping/maps 77:subsidies/support measures 78:trade liberalization/regulations 79:fuels/fuel crops 81:tourism impact/destinations 82:pastures/range management 83:wild animals/wildlife 84:refuse/waste treatment
86:land ownership/land policy 87:carbon sequestration/carbon dioxide
88:grasslands/botanical composition 89:indigenous knowledge/plant genetic resources
90:outdoor recreation/visitors
91:weed control/agricultural entomology 92:regulations/exports
94:low input agriculture/maize 95:irrigation systems/water use efficiency 96:forest policy/private forestry
97:satellite imagery/remote sensing 98:wildlife management/wild animals
99:tenure systems/land reform 100:polluted water/pollutants 101:bioremediation/risk assessment
102:polluted water/leaching
103:natural resource economics/resources 104:waste management/waste water
105:water allocation/irrigation water 106:carbon dioxide/carbon sequestration
107:species richness/botanical composition 108:forest policy/forest resources
109:tourist industry/destinations
110:tenure systems/land ownership
111:biology/agricultural entomology
112:control/plant pests 113:soyabeans/low input agriculture 114:forest policy/forest economics
115:economic theory/resource allocation 116:agricultural trade/world trade organization
119:waste utilization/refuse
120:world trade organization/trade liberalization
121:water policy/irrigation water
122:utilization/arid zones
9:agricultural research/agricultural development 11:food security/food production
17:development policy/economic development 18:floodplains/natural disasters
20:innovation adoption/diffusion of information 24:deforestation/trees
25:international agreements/international cooperation
28:drainage/reclamation 29:pest control/weeds
32:land management/landscape conservation 33:temperature/economic impact
37:grazing/grassland management
38:technical progress/innovation adoption 40:private ownership/property rights
41:transition economies/agricultural situation 42:forest economics/valuation
43:efficiency/farm inputs 44:drainage systems/water table
46:soil fertility/soil conservation 47:fishing/fishery policy
48:maps/remote sensing 49:land policy/public domain
50:population growth/population pressure 52:urbanization/agricultural land 53:cap/subsidies
55:renewable resources/fuel crops
56:precipitation/climate
57:community forestry/social participation
58:intellectual property rights/indigenous knowledge
59:floods/flooding 60:social impact/economic impact 63:refuse/waste water treatment
66:bioenergy/greenhouse gases
67:biotechnology/genetic engineering 68:catchment hydrology/runoff 69:production/exports
70:water use efficiency/trickle irrigation 71:sediment/soil conservation 72:runoff/groundwater 73:nitrates/pollution control 74:groundwater/irrigation water 75:fishery resources/fishing 76:mapping/maps 77:subsidies/support measures 78:trade liberalization/regulations 79:fuels/fuel crops 81:tourism impact/destinations 82:pastures/range management 83:wild animals/wildlife 84:refuse/waste treatment
86:land ownership/land policy 87:carbon sequestration/carbon dioxide
88:grasslands/botanical composition 89:indigenous knowledge/plant genetic resources
90:outdoor recreation/visitors
91:weed control/agricultural entomology 92:regulations/exports
94:low input agriculture/maize 95:irrigation systems/water use efficiency 96:forest policy/private forestry
97:satellite imagery/remote sensing 98:wildlife management/wild animals
99:tenure systems/land reform 100:polluted water/pollutants 101:bioremediation/risk assessment
102:polluted water/leaching
103:natural resource economics/resources 104:waste management/waste water
105:water allocation/irrigation water 106:carbon dioxide/carbon sequestration
107:species richness/botanical composition 108:forest policy/forest resources
109:tourist industry/destinations
110:tenure systems/land ownership
111:biology/agricultural entomology
112:control/plant pests 113:soyabeans/low input agriculture 114:forest policy/forest economics
115:economic theory/resource allocation 116:agricultural trade/world trade organization
119:waste utilization/refuse
120:world trade organization/trade liberalization
121:water policy/irrigation water
122:utilization/arid zones
1998-2001 1999-2002 2000-2003
9:agricultural research/agricultural development 11:food security/food production
17:development policy/economic development 18:floodplains/natural disasters
20:innovation adoption/diffusion of information 24:deforestation/trees
25:international agreements/international cooperation
28:drainage/reclamation 29:pest control/weeds
32:land management/landscape conservation 33:temperature/economic impact
37:grazing/grassland management
38:technical progress/innovation adoption 40:private ownership/property rights
41:transition economies/agricultural situation 42:forest economics/valuation
43:efficiency/farm inputs 44:drainage systems/water table
46:soil fertility/soil conservation 47:fishing/fishery policy
48:maps/remote sensing 49:land policy/public domain
50:population growth/population pressure 52:urbanization/agricultural land 53:cap/subsidies
55:renewable resources/fuel crops
56:precipitation/climate
57:community forestry/social participation
58:intellectual property rights/indigenous knowledge
59:floods/flooding 60:social impact/economic impact 63:refuse/waste water treatment
66:bioenergy/greenhouse gases
67:biotechnology/genetic engineering 68:catchment hydrology/runoff 69:production/exports
70:water use efficiency/trickle irrigation 71:sediment/soil conservation 72:runoff/groundwater 73:nitrates/pollution control 74:groundwater/irrigation water 75:fishery resources/fishing 76:mapping/maps 77:subsidies/support measures 78:trade liberalization/regulations 79:fuels/fuel crops 81:tourism impact/destinations 82:pastures/range management 83:wild animals/wildlife 84:refuse/waste treatment
86:land ownership/land policy 87:carbon sequestration/carbon dioxide
88:grasslands/botanical composition 89:indigenous knowledge/plant genetic resources
90:outdoor recreation/visitors
91:weed control/agricultural entomology
92:regulations/exports
94:low input agriculture/maize 95:irrigation systems/water use efficiency 96:forest policy/private forestry
97:satellite imagery/remote sensing 98:wildlife management/wild animals
99:tenure systems/land reform 100:polluted water/pollutants 101:bioremediation/risk assessment
102:polluted water/leaching
103:natural resource economics/resources 104:waste management/waste water
105:water allocation/irrigation water 106:carbon dioxide/carbon sequestration
107:species richness/botanical composition 108:forest policy/forest resources
109:tourist industry/destinations
110:tenure systems/land ownership
111:biology/agricultural entomology 112:control/plant pests
113:soyabeans/low input agriculture 114:forest policy/forest economics
115:economic theory/resource allocation 116:agricultural trade/world trade organization
119:waste utilization/refuse
120:world trade organization/trade liberalization
121:water policy/irrigation water
122:utilization/arid zones
9:agricultural research/agricultural development 11:food security/food production
17:development policy/economic development 18:floodplains/natural disasters
20:innovation adoption/diffusion of information 24:deforestation/trees
25:international agreements/international cooperation
28:drainage/reclamation 29:pest control/weeds
32:land management/landscape conservation 33:temperature/economic impact
37:grazing/grassland management
38:technical progress/innovation adoption 40:private ownership/property rights
41:transition economies/agricultural situation 42:forest economics/valuation
43:efficiency/farm inputs 44:drainage systems/water table 46:soil fertility/soil conservation 47:fishing/fishery policy
48:maps/remote sensing 49:land policy/public domain
50:population growth/population pressure 52:urbanization/agricultural land 53:cap/subsidies
55:renewable resources/fuel crops
56:precipitation/climate
57:community forestry/social participation
58:intellectual property rights/indigenous knowledge
59:floods/flooding 60:social impact/economic impact 63:refuse/waste water treatment
66:bioenergy/greenhouse gases
67:biotechnology/genetic engineering 68:catchment hydrology/runoff 69:production/exports
70:water use efficiency/trickle irrigation 71:sediment/soil conservation 72:runoff/groundwater 73:nitrates/pollution control 74:groundwater/irrigation water 75:fishery resources/fishing 76:mapping/maps 77:subsidies/support measures 78:trade liberalization/regulations 79:fuels/fuel crops 81:tourism impact/destinations 82:pastures/range management 83:wild animals/wildlife 84:refuse/waste treatment
86:land ownership/land policy 87:carbon sequestration/carbon dioxide
88:grasslands/botanical composition 89:indigenous knowledge/plant genetic resources
90:outdoor recreation/visitors
91:weed control/agricultural entomology 92:regulations/exports
94:low input agriculture/maize 95:irrigation systems/water use efficiency 96:forest policy/private forestry
97:satellite imagery/remote sensing 98:wildlife management/wild animals
99:tenure systems/land reform 100:polluted water/pollutants 101:bioremediation/risk assessment
102:polluted water/leaching
103:natural resource economics/resources 104:waste management/waste water
105:water allocation/irrigation water 106:carbon dioxide/carbon sequestration
107:species richness/botanical composition 108:forest policy/forest resources
109:tourist industry/destinations
110:tenure systems/land ownership
111:biology/agricultural entomology 112:control/plant pests
113:soyabeans/low input agriculture 114:forest policy/forest economics
115:economic theory/resource allocation 116:agricultural trade/world trade organization
119:waste utilization/refuse
120:world trade organization/trade liberalization
121:water policy/irrigation water
122:utilization/arid zones
9:agricultural research/agricultural development 11:food security/food production
17:development policy/economic development 18:floodplains/natural disasters
20:innovation adoption/diffusion of information 24:deforestation/trees
25:international agreements/international cooperation
28:drainage/reclamation 29:pest control/weeds
32:land management/landscape conservation 33:temperature/economic impact
37:grazing/grassland management
38:technical progress/innovation adoption 40:private ownership/property rights
41:transition economies/agricultural situation 42:forest economics/valuation
43:efficiency/farm inputs 44:drainage systems/water table
46:soil fertility/soil conservation 47:fishing/fishery policy
48:maps/remote sensing 49:land policy/public domain
50:population growth/population pressure 52:urbanization/agricultural land 53:cap/subsidies
55:renewable resources/fuel crops
56:precipitation/climate
57:community forestry/social participation
58:intellectual property rights/indigenous knowledge
59:floods/flooding 60:social impact/economic impact 63:refuse/waste water treatment
66:bioenergy/greenhouse gases
67:biotechnology/genetic engineering 68:catchment hydrology/runoff 69:production/exports
70:water use efficiency/trickle irrigation 71:sediment/soil conservation 72:runoff/groundwater 73:nitrates/pollution control 74:groundwater/irrigation water 75:fishery resources/fishing 76:mapping/maps 77:subsidies/support measures 78:trade liberalization/regulations 79:fuels/fuel crops 81:tourism impact/destinations 82:pastures/range management 83:wild animals/wildlife 84:refuse/waste treatment
86:land ownership/land policy 87:carbon sequestration/carbon dioxide
88:grasslands/botanical composition 89:indigenous knowledge/plant genetic resources
90:outdoor recreation/visitors
91:weed control/agricultural entomology 92:regulations/exports
94:low input agriculture/maize 95:irrigation systems/water use efficiency 96:forest policy/private forestry
97:satellite imagery/remote sensing 98:wildlife management/wild animals
99:tenure systems/land reform 100:polluted water/pollutants 101:bioremediation/risk assessment
102:polluted water/leaching
103:natural resource economics/resources 104:waste management/waste water
105:water allocation/irrigation water 106:carbon dioxide/carbon sequestration
107:species richness/botanical composition 108:forest policy/forest resources
109:tourist industry/destinations
110:tenure systems/land ownership
111:biology/agricultural entomology 112:control/plant pests
113:soyabeans/low input agriculture 114:forest policy/forest economics
115:economic theory/resource allocation
116:agricultural trade/world trade organization
119:waste utilization/refuse
120:world trade organization/trade liberalization
121:water policy/irrigation water
122:utilization/arid zones 2001-2004 2002-2005 2003-2006 0 1 0.5 0.75 0.25
9:agricultural research/agricultural development 11:food security/food production
17:development policy/economic development 18:floodplains/natural disasters
20:innovation adoption/diffusion of information 24:deforestation/trees
25:international agreements/international cooperation
28:drainage/reclamation 29:pest control/weeds
32:land management/landscape conservation 33:temperature/economic impact
37:grazing/grassland management
38:technical progress/innovation adoption 40:private ownership/property rights
41:transition economies/agricultural situation 42:forest economics/valuation
43:efficiency/farm inputs 44:drainage systems/water table 46:soil fertility/soil conservation 47:fishing/fishery policy
48:maps/remote sensing 49:land policy/public domain
50:population growth/population pressure 52:urbanization/agricultural land 53:cap/subsidies
55:renewable resources/fuel crops
56:precipitation/climate
57:community forestry/social participation
58:intellectual property rights/indigenous knowledge
59:floods/flooding 60:social impact/economic impact 63:refuse/waste water treatment
66:bioenergy/greenhouse gases
67:biotechnology/genetic engineering 68:catchment hydrology/runoff 69:production/exports
70:water use efficiency/trickle irrigation 71:sediment/soil conservation 72:runoff/groundwater 73:nitrates/pollution control 74:groundwater/irrigation water 75:fishery resources/fishing 76:mapping/maps 77:subsidies/support measures 78:trade liberalization/regulations 79:fuels/fuel crops 81:tourism impact/destinations 82:pastures/range management 83:wild animals/wildlife 84:refuse/waste treatment
86:land ownership/land policy 87:carbon sequestration/carbon dioxide
88:grasslands/botanical composition 89:indigenous knowledge/plant genetic resources
90:outdoor recreation/visitors
91:weed control/agricultural entomology 92:regulations/exports
94:low input agriculture/maize 95:irrigation systems/water use efficiency 96:forest policy/private forestry
97:satellite imagery/remote sensing 98:wildlife management/wild animals
99:tenure systems/land reform 100:polluted water/pollutants 101:bioremediation/risk assessment
102:polluted water/leaching
103:natural resource economics/resources 104:waste management/waste water
105:water allocation/irrigation water 106:carbon dioxide/carbon sequestration
107:species richness/botanical composition 108:forest policy/forest resources
109:tourist industry/destinations
110:tenure systems/land ownership
111:biology/agricultural entomology 112:control/plant pests
113:soyabeans/low input agriculture 114:forest policy/forest economics
115:economic theory/resource allocation
116:agricultural trade/world trade organization 119:waste utilization/refuse
120:world trade organization/trade liberalization
121:water policy/irrigation water
122:utilization/arid zones
2004-2007
FIGURE4.23: Evolution de la projection de l’auteur 478 (Philip Lowe) sur les 10 dernières années (fenêtres glissantes de 4 ans)
1. les champs associés à une forte densité de présence de l’auteur (zones rouges) sont contigus sur notre carte, ce qui tend à valider la reconstruction statique,
2. la densité de présence de l’auteur dans cet espace est centrée sur un ensemble de champs semblant correspondre aux domaines d’expertise du chercheur (principalement les aspects économiques et légaux des échanges commer- ciaux internationaux, mais également des domaines connexes)
3. la densité de présence de l’auteur évolue très peu dans le temps, laissant penser que le chercheur représenté ici est resté “fidèle” aux communautés épistémiques auxquelles il participe,
4. lorsqu’il y a dispersion vers d’autres champs — c’est à dire activation de nouveaux champs — les champs touchés semblent être proches des champs activés précédemment, i.e. les champs nouvellement peuplés se situent dans
le voisinage immédiat des champs précédemment occupés30.
Ces observations semblent donc valider nos reconstructions, et suggèrent une certaine forme de stabilité dans l’engagement des chercheurs auprès d’une com- munauté épistémique donnée. Nous cherchons maintenant à rendre compte de façon plus rigoureuse de l’attraction exercée sur les scientifiques par leurs champs épistémiques d’appartenance à travers le calcul de mesures d’attachement préfé- rentiel liant la structure des champs à l’évolution de l’activité des chercheurs.