Transcript Document
CS 785 Fall 2004 Gheorghe Tecuci [email protected] http://lac.gmu.edu/ Learning Agents Center and Computer Science Department George Mason University 2004, G.Tecuci, Learning Agents Center Overview Semantic networks Ontology representation Reasoning with an ontology Development and maintenance of an ontology Sample ontology for COG analysis Ontology development tools Exercises and readings 2004, G.Tecuci, Learning Agents Center Semantic networks The underlying idea of semantic networks is to represent knowledge in the form of a graph in which the nodes represent objects, situations, or events, and the arcs represent the relationships between them. person Roman isa isa man P ompeian instance-of instance-of 72 2004, G.Tecuci, Learning Agents Center height Marcus t ryassassinat e ruler instance-of Caesar Semantic networks with binary relations yellow What does this semantic network express? color mass Sun t emperat ure MSun T Sun at t ract s greater-t han greater-t han revolvesarround 3500 value MEart h mass 2004, G.Tecuci, Learning Agents Center T Eart h Earth t emperat ure Representing non-binary predicates What does this semantic network express? bird isa nest robin instance-of Clyde instance-of owns nest-1 How can one encode the additional information that Clyde owned nest-1 from Spring 90 to Fall 90? A binary relation cannot encode this additional information. We need to represent ownership as a node rather than a relation. 2004, G.Tecuci, Learning Agents Center Representing non-binary predicates ownership(owner, ownee, start-time, end-time) bird isa robin instance-of Clyde ownership nest instance-of nest -1 owner instance-of own-1 ownee start -t ime end-t ime Spring-90 Fall-90 A semantic network representing "ownership" as a node. 2004, G.Tecuci, Learning Agents Center Overview Exercise Represent the following sentences into a semantic network: Birds are animals. Birds have feathers, fly and lay eggs. Albatros is a bird. Donald is a bird. Tracy is an albatros. 2004, G.Tecuci, Learning Agents Center Overview Semantic networks Ontology representation Reasoning with an ontology Development and maintenance of an ontology Sample ontology for COG analysis Ontology development tools Exercises and readings 2004, G.Tecuci, Learning Agents Center Ontology representation 1. What is an ontology 2. Sample application domain 3. Concepts, instances, and generalization 4. Object features 5. Definition of instances and concepts 2004, G.Tecuci, Learning Agents Center 1. What is an ontology Every knowledge-based agent has a conceptualization or a model (i.e. an abstract, simplified view) of its world which consists of representations of the objects, concepts, and other entities that are assumed to exist, and the relationships that hold among them. An ontology is a specification of the terms that are used to represent the agent’s world. In an ontology, definitions associate the names of entities in the agent’s world (e.g., classes, individual objects, relations, tasks) with human-readable text describing what the names mean, and formal axioms that constrain the interpretation and use of these terms. 2004, G.Tecuci, Learning Agents Center Why is the definition of an agent’s ontology important? Enables an agent to communicate with other agents, because they share a common vocabulary (terms) which they both understand. Enables knowledge sharing and reuse among agents. Ontological commitment: Agreement among several agents to use a shared vocabulary in a coherent and consistent manner. 2004, G.Tecuci, Learning Agents Center Object ontology We define an object ontology as a hierarchical description of the objects from the agent’s domain, specifying their properties and relationships. It includes both descriptions of types of objects (called concepts) and descriptions of specific objects (called instances). 2004, G.Tecuci, Learning Agents Center The generality of the object ontology An object ontology is characteristic to an entire application domain, such as military or medicine. In the military domain the object ontology will include descriptions of military units and of military equipment. These descriptions are most likely needed in almost any specific military application. Because building the object ontology is a very complex task, it makes sense to reuse these descriptions when developing a knowledge base for another military application, rather than starting from scratch. 2004, G.Tecuci, Learning Agents Center 2. Sample application domain Center of Gravity Analysis Identify COG candidates Identify potential primary sources of moral or physical strength, power and resistance from: Government Military Test each identified COG candidate to determine whether it has all the necessary critical capabilities: Which are the critical capabilities? People Are the critical requirements of these capabilities satisfied? Economy If not, eliminate the candidate. Alliances If yes, do these capabilities have any vulnerability? Etc. 2004, G.Tecuci, Learning Agents Center Test COG candidates 3. Concepts, instances, and generalization A concept is a representation of a set of instances. state_government instance_of government_of_US_1943 instance_of Represents the set of all entities that are governments of states. This set includes “government_of_US_1943” and government_of_Britain_1943” government_of_Britain_1943 state_government government_of_US_1943 government_of_Britain_1943 Provide another example of a concept. 2004, G.Tecuci, Learning Agents Center Characterization of instances An instance is a representation of a particular entity in the application domain. state_government instance_of government_of_US_1943 instance_of government_of_Britain_1943 Represents the entity called “government_of_US_1943” “instance_of” is the relationship between an instance and the concept to which it belongs. Provide another example of an instance and of a concept. 2004, G.Tecuci, Learning Agents Center Intuitive definition of generalization Intuitively, a concept P is said to be more general than (or a generalization of) another concept Q if and only if the set of instances represented by P includes the set of instances represented by Q. Example: state_government democratic_government representative_ democracy parliamentary_ democracy totalitarian_ government state_government “subconcept_of” is the relationship between a concept and a more general concept. subconcept_of democratic_government 2004, G.Tecuci, Learning Agents Center Intuitive definition of generalization (cont.) What are the possible relationships between two concepts A and B, from a generalization point of view? - A is more general than B - B is more general than A - There is no generalization relationship between A and B Provide examples of concepts A and B in each of these three situations. 2004, G.Tecuci, Learning Agents Center Intuitive definition of generalization (cont.) How could one prove that A is more general than B? Show that all the instances of B are also instances of A B Is this always a practical procedure? A No if A and B have an infinite number of instances. How can one prove that A is not more general than B? Show that B contains an instance which is not an instance of A. . B A Is this a more practical procedure? Yes, even for concepts with an infinite number of instances. 2004, G.Tecuci, Learning Agents Center A generalization hierarchy governing_body ad_hoc_ governing_body established_ governing_body other_type_of_ governing_body state_government group_governing_body feudal_god_ king_government other_state_ government democratic_ government monarchy other_ group_ governing_ body dictator deity_figure representative_ parliamentary_ democracy democracy government_ of_Italy_1943 totalitarian_ government police_ state government_ of_US_1943 government_ of_Britain_1943 military_ dictatorship religious_ dictatorship democratic_ council_ or_board autocratic_ leader fascist_ state communist_ dictatorship 2004, G.Tecuci, Learning Agents Center government_ of_USSR_1943 theocratic_ government religious_ dictatorship government_ of_Germany_1943 theocratic_ democracy chief_and_ tribal_council Partially learned concepts and version spaces Question: What is the concept represented by the following two positive examples P = {government_of_US_1943, government_of_Britain_1943} and the following negative example N = {GMU_governing_body_2004} ? governing_body established_governing_body . state_government . democratic_government representative_ democracy 2004, G.Tecuci, Learning Agents Center . parliamentary_ democracy totalitarian_ government Partially learned concepts and version spaces Question: What is the concept represented by the following two positive examples P = {government_of_US_1943, government_of_Britain_1943} and the following negative example N = {GMU_governing_body_2004} ? . Upper bound of the VS state_government . Lower bound of the VS democratic_government 2004, G.Tecuci, Learning Agents Center . Version Space (VS) upper bound: {state_government} lower bound: {democratic_government} Object descriptions The objects in the application domain may be described in terms of their properties and their relationships with each other. parliamentary_democracy instance_of has_as_head_of_government Winston_Churchill government_of_Britain_1943 has_as_legislative_body parliament_of_Britain_1943 government_of_Britain_1943 has_as_legislative_body parliament_of_Britain_1943 Similarly, a general object or concept can be described as being a subconcept of an even more general concept and having additional features. 2004, G.Tecuci, Learning Agents Center Feature definition An object feature is itself characterized by several features which include: documentation, domain and range. The domain is the concept that represents the set of objects that could have that feature. The range is the set of possible values of the feature. has_as_political_leader subconcept_of has_as_head_of_government documentation domain range 2004, G.Tecuci, Learning Agents Center "Indicates the head of a governing body" governing_body person Partially learned feature Allied_Forces_1943 has_as_strategic_goal documentation has_as_strategic_goal domain range 2004, G.Tecuci, Learning Agents Center Unconditional_surrender_of_European_Axis_1943 "Indicates the strategic goal of an entity” plausible upper bound: agent plausible lower bound: force plausible upper bound: agent_goal plausible lower bound: force_goal Feature hierarchy has_as_controlling_leader D: agent R: person has_as_religious_leader D: governing_body R: person has_as_god_king D: governing_body R: person has_as_monarch D: governing_body R: person has_as_military_leader D: governing_body R: person has_as_political_leader D: governing_body R: person has_as_head_of_government D: governing_body R: person 2004, G.Tecuci, Learning Agents Center has_as_commander_in_chief D: force R: person has_as_head_of_state D: governing_body R: person Exercise Consider the following feature hierarchy: DOMAIN 1D1 RANGE 1R1 Is there any relationship between: Feature 1 BD1 and 1D1? DOMAIN BD1 Feature B A2D1 and 1D1? RANGE BR1 DOMAIN AD1 RANGE AR1 AD1 and BD1? Feature A Feature A1 1D1 and 1R1? DOMAIN A2D1 RANGE A2R1 Feature A2 2004, G.Tecuci, Learning Agents Center 5. Definition of instances and concepts When designing a knowledge base, one has to first specify some basic concepts, as well as the features that may characterize the instances and the concepts from the application domain. Once basic concepts and features are specified, one can define new concepts and instances as logical expressions of the specified concepts and features. 2004, G.Tecuci, Learning Agents Center Basic representation unit conceptk ISA FEATURE1 ... FEATUREn concepti value1 valuen This is a necessary definition of ‘conceptk’. It defines ‘conceptk’ as being a subconcept of ‘concepti’ and having additional features. This means that if ‘concepti’ represents the set Ci of instances, then ‘conceptk’ represents a subset Ck of Ci. The elements of Ck have the features ‘FEATURE1’,..., ‘FEATUREn’ with the values ‘value1’,..., ‘valuen’, respectively. 2004, G.Tecuci, Learning Agents Center Overview Semantic networks Ontology representation Reasoning with an ontology Development and maintenance of an ontology Sample ontology for COG analysis Ontology development tools Exercises and readings 2004, G.Tecuci, Learning Agents Center Reasoning with an ontology 1. Transitivity of “instance_of” and “subconcept_of” 2. Inheritance 3. Concept expressions 4. Ontology matching 5. Rules as ontology-based representations 2004, G.Tecuci, Learning Agents Center 1. Transitivity of “instance_of” and “subconcept_of” established_governing_body established_governing_body subconcept_of state_government state_government subconcept_of subconcept_of democratic_government democratic_government subconcept_of representative_democracy instance_of instance_of government_of_US_1943 government_of_US_1943 2004, G.Tecuci, Learning Agents Center 2. Inheritance Properties associated with concepts in a hierarchy are assumed to be true of all subconcepts and instances. democratic_ government has_as_dominant_ “will of the people” psychosocial_factor representative_ democracy government_ of_US_1943 2004, G.Tecuci, Learning Agents Center has_as_political_leader President_Roosevelt Exceptions to default inheritance Properties associated with concepts in a hierarchy are assumed to be true of all subconcepts and instances. How can we deal with exceptions (i.e. sub-concepts or instances that do not have the inherited property)? Explicitly override the inherited property, as illustrated in the following slide. 2004, G.Tecuci, Learning Agents Center Exceptions to default inheritance: illustration democratic_ government has_as_dominant_ “will of the people” psychosocial_factor representative_ democracy government_ of_US_1943 has_as_political_leader President_Roosevelt parliamentary_ has_as_dominant_psychosocial_factor {“will of the people” “will of the parliament”} democracy has_as_dominant_psychosocial_factor “will of the people” government_ of_Britain_1943 has_as_political_leader 2004, G.Tecuci, Learning Agents Center Winston_Churchill Multiple inheritance An object (instance or concept) may inherit properties from several super-concepts. How can we deal with the inheritance of contradictory properties? Explicitly state the property of the object, instead of inheriting it: south pole habitat cartoon character penguin instance-of instance-of Opus 2004, G.Tecuci, Learning Agents Center habitat funny papers 3. Concept expressions One can define more complex concepts as logical expressions involving the basic concepts from the object ontology. In the following expression, for instance, ?O1 represents a force that has as industrial factor an industrial capacity that generates essential war materiel from the strategic perspective of a multi-member force that includes ?O1. ?O1 ?O2 ?O3 is force has_as_industrial_factor ?O2 is industrial_capacity generates_essential_war_materiel_from_ the_strategic_perspective_of is multi_member_force has_as_member ?O1 2004, G.Tecuci, Learning Agents Center ?O3 4. Ontology matching Ontology matching allows one to answer complex questions about the knowledge represented in the ontology, as illustrated in the following: Question: Is there any force ?O1 that has as industrial factor an industrial capacity that generates essential war materiel from the strategic perspective of a multi-member force that includes ?O1? Answer: Yes, US_1943 is a force that has as industrial factor industrial_capacity_of_US_1943 that generates essential war materiel from the strategic perspective of the Allied_Forces_1943 which is a multi-member force that includes US_1943. 2004, G.Tecuci, Learning Agents Center Ontology matching: example Question Object ontology Answer ?O1 US_1943 force ?O2 industrial_capacity_ of_US_1943 force ?O3 Allied_forces_1943 instance-of subconcept-of single_member_force subconcept-of single_state_force ?O1 industrial_capacity instance-of has_as_industrial_factor instance-of multi_state_force has_as_member instance-of ?O2 generates_essential_ war_materiel_from_ the_ strategic_perspective_of ?O3 Is there any force ?O1 that has as industrial factor an industrial capacity that generates essential war materiel from the strategic perspective of a multi-member force that includes ?O1? 2004, G.Tecuci, Learning Agents Center US_1943 industrial_capacity has_as_industrial_factor instance-of Industrial_capacity_ multi_state_force of_US_1943 subconcept-of multi_state_ alliance subconcept-of generates_essential_ equal_partner_ war_materiel_from_ the_ multi_state_ strategic_perspective_of alliance has_as_member instance-of Allied_forces_1943 5. Rules as ontology-based representations of PSS IF Identify and test a strategic COG candidate corresponding to the economy of a force which is an industrial economy The industrial economy is ?O1 Condition ?O1 is industrial_economy ?O2 is industrial_capacity generates_essential_war_materiel_from_ the_strategic_perspective_of ?O3 ?O3 is multi_state_force has_as_member ?O4 ?O4 is force has_as_economy ?O1 has_as_industrial_factor ?O2 THEN Identify a strategically critical element as a COG candidate with respect to an industrial economy The strategically critical element is ?O2 The industrial economy is ?O1 Test a strategically critical element which is a strategic COG candidate with respect to an industrial economy The strategically critical element is ?O2 The industrial economy is ?O1 A rule is an ontology-based representation of a problem solving step (PSS). 2004, G.Tecuci, Learning Agents Center Condition: ?O1 is an industrial economy ?O2 is an industrial capacity which generates essential war material from the strategic perspective of ?O3, a multistate force which has as member ?O4 (a force which has as economy ?O1 and as industrial factor ?O2). This rule will be applicable only if the current ontology contains instances of the concepts ?O1, ?O2, ?O3, and ?O4 represented in the condition. Overview Semantic networks Ontology representation Reasoning with an ontology Development and maintenance of an ontology Sample ontology for COG analysis Ontology development tools Exercises and readings 2004, G.Tecuci, Learning Agents Center Ontology maintenance Maintaining the consistency of the object ontology is a complex knowledge engineering activity because the object and feature definitions interact in complex ways. Example: Deleting an object concept requires the updating of all the knowledge base elements that refer to it (e.g. the rules that contain it in their conditions; the features that contain it in their ranges or domains; the concepts that inherit its features). 2004, G.Tecuci, Learning Agents Center Potential consequence of editing operations: Illustration f domain A f domain A A A B B C Initial State f 7 C f Modified State Explain why. Because C is no longer in the domain of f. 2004, G.Tecuci, Learning Agents Center If we delete the link from B to A, then C can no longer have the feature f 7 Steps in ontology development 1. Define the basic concepts, and their organization into a hierarchical structure (the generalization hierarchy). 2. Define the generic features, using the previously defined concepts to specify their domains and ranges. 3. Use the defined concepts and feature to define instances. 4. Extend the ontology with new concepts, features, and instances. 5. Repeat steps 1,2,3,4 until the ontology is judged to be complete enough. 2004, G.Tecuci, Learning Agents Center Steps in ontology development: illustration object resource_or_infrastructure_element agent_goal scenario agent force_goal 1. Define basic concepts strategic_goal strategic_cog_relevant_factor force other_relevant_factor operational_goal theater_strategic_goal psychosocial_factor political_factor demographic_factor military_factor economic_factor historic_factor geographic_factor international_factor has_as_force_goal documentation 2. Use the basic concepts to define features has_as_strategic_goal has_as_operational_goal 3. Use the defined concepts and features to define instances. 2004, G.Tecuci, Learning Agents Center domain range "Indicates the strategic goal of an entity” plausible upper bound: agent plausible lower bound: force plausible upper bound: agent_goal plausible lower bound: force_goal force_goal force has_as_strategic_goal Allied_Forces_1943 Unconditional_surrender_of_European_Axis_1943 General features of semantic networks and ontologies Representational adequacy: High for binary relationships. Inferential adequacy: Good for certain types of inferential procedures. Inferential efficiency: very high The structure used for representing knowledge is also a guide for the retrieval of the knowledge. Acquisitional efficiency: very low 2004, G.Tecuci, Learning Agents Center Overview Semantic networks Ontology representation Reasoning with an ontology Development and maintenance of an ontology Sample ontology for COG analysis Ontology development tools Exercises and readings 2004, G.Tecuci, Learning Agents Center The object hierarchy Overall organization Scenario Forces and goals Economic factors Geographic factors Military factors Political factors Other objects 2004, G.Tecuci, Learning Agents Center Overall organization of the COG object ontology object resource_or_infrastructure_element agent_goal scenario force_goal strategic_goal agent strategic_cog_relevant_factor force other_relevant_factor operational_goal theater_strategic_goal psychosocial_factor political_factor demographic_factor military_factor economic_factor historic_factor geographic_factor 2004, G.Tecuci, Learning Agents Center international_factor subconcept_of Scenario object scenario agent war_scenario force Sicily_1943 brief_description description opposing_force “The Allied decision to invade Sicily following the successful operation in North Africa was a critical element of World War II [WWII]. The commitment of such a large force to continue operations in the Mediterranean theater meant that the cross-channel invasion of Europe would be delayed. American military leaders strongly favored the cross-channel invasion at the earliest possible opportunity. This meant giving this invasion force first priority for troops, shipping and equipment. The British favored an indirect approach that would see a major effort continue in the Mediterranean. The Allies settled on the Mediterranean approach at the Casablanca conference in January 1943 and began planning for Operation Husky, the invasion of Sicily. Situated ninety miles off the north coast of Africa and two and one-half miles from the toe of the Italian peninsula, Sicily was both a natural bridge between Africa and Europe and a barrier dividing the Mediterranean Sea. It was an unsinkable air and naval fortress from which Axis forces interdicted Allied sea lines of communications through the Mediterranean. …” has_as_opposing_force has_as_opposing_force 2004, G.Tecuci, Learning Agents Center “WWII Allied invasion of Sicily in 1943” Allied_Forces_1943 European_Axis_1943 Forces force military_force group opposing_force multi_member_force multi_group_force supporting_force single_member_force legal_group illegal_group single_state_force multi_state_force single_group_force multi_state_alliance multi_state_coalition dominant_partner_ equal_partners_ multi_state_alliance multi_state_alliance has_as_member Allied_Forces_1943 has_as_member has_as_member has_as_member European_Axis_1943 has_as_member 2004, G.Tecuci, Learning Agents Center Germany_1943 Italy_1943 US_1943 Britain_1943 USSR_1943 Forces (continued) group single_group_force legal_group illegal_group … legal_business_group clan_or_tribe other_legal_group military_group_or_clan military_group_or_unit military_clan para_military_group 2004, G.Tecuci, Learning Agents Center Forces (continued) illegal_group other_illegal_group profit_focused_illegal_group crime_gang crime_family drug_cartel vice_ring purpose_focused_illegal_groups hate_group terrorist_cell extremist_group 2004, G.Tecuci, Learning Agents Center separatists religious_cult personality_cult Force goals force_goal strategic_goal Allied_Forces_1943 has_as_strategic_goal Unconditional_surrender_ description “The strategic goals of the US-British alliance in of_European_Axis_1943 1943 were to defeat Germany first while containing Japan, to keep Russia in the war on the side of the Allies, and the eventual unconditional surrender of all Axis countries. To theater_strategic_goal accomplish these goals, US leaders favored an has_as_theater_strategic_goal early, direct attack into northern Europe. …” Taking_Italy_out_of_war_ description against_Allies_and_keeping_ “…“ USSR_in_war_alongside_Allies operational_goal has_as_operational_goal 2004, G.Tecuci, Learning Agents Center Capturing_of_the_ island_of_Sicily description “The operational goals of the Allies were to secure sea lines of communications in the Mediterranean Sea, divert German combat power from the Russian front, and knock Italy out of the war. …” Economic factors economic_factor other_ economic_ factor commerce_ authority information_ network_or_system raw_material transportation_ factor industrial_ factor strategic_ raw_ material industrial_ authority oil_chromium_ copper_and_bauxite_ of_Germany_1943 transportation_ center war_materiel_of _Germany_1943 produces_war_materiel_for is_obtained_from 2004, G.Tecuci, Learning Agents Center transportation_ network_or_system industrial_capacity_ of_US_1943 has_as_strategic_ raw_material Germany_1943 … industrial_ capacity industrial_ center is_critical_to_ the_production_of type_of_ economy Balkans has_as_industrial_factor US_1943 US_1943_ Economic factors (continued) type_of_economy industrial_economy other_type_of_economy informational_economy economy_of_US_1943 has_as_economy US_1943 2004, G.Tecuci, Learning Agents Center pre_industrial_economy Geographic factors geographic_factor place geographic_ center_of_power “The US has extremely long and external lines of communication. Some US forces deployed directly from the US for the invasion of North Africa and much of the shipping and naval forces for Sicily will come directly from the US for operation Husky.” capital US_1943 has_as_capital Washington_DC description has_as_other_geographic_factor 2004, G.Tecuci, Learning Agents Center other_geographic_factors_of_US_1943 Military factors military_factor military_requirement composition_of_forces other_military_factor military_capability … critically_important_ military_requirement single_member_force critically_important_ military_capability multi_member_force nuclear_weapons single_state_force single_group_force multi_state_alliance dominant_partner_ multi_state_alliance European_ Axis_1943 multi_state_coalition dominant_partner_ multi_state_coalition equal_partners_ multi_state_alliance Allied_Forces_1943 2004, G.Tecuci, Learning Agents Center multi_state_force multi_group_force multi_group_alliance dominant_partner_ multi_group_alliance equal_partners_ multi_state_coalition multi_group_coalition dominant_partner_ multi_group_coalition equal_partners_ multi_group_alliance equal_partners_ multi_group_coalition Military factors (cont.) other_military_factor essential_military_contribution geographical_entre manpower significance_of_ military_contribution critical_terrain secondary_military_contribution essential_war_materiel minor_military_contribution most_important_ military_contribution important_indirect_ military_contribution military_contribution_of_USSR_1943 shared_primary_ military_contribution military_contribution_of_US_1943 has_as_military_contribution has_as_military_contribution USSR_1943 2004, G.Tecuci, Learning Agents Center US_1943 Political factors political_factor governing_body 2004, G.Tecuci, Learning Agents Center controlling_element other_political_factor Political factors: Governing body governing_body ad_hoc_ governing_body established_ governing_body other_type_of_ governing_body state_government group_governing_body feudal_god_ king_government other_state_ government democratic_ government monarchy other_ group_ governing_ body dictator deity_figure representative_ parliamentary_ democracy democracy government_ of_Italy_1943 totalitarian_ government police_ state government_ of_US_1943 government_ of_Britain_1943 military_ dictatorship religious_ dictatorship democratic_ council_ or_board autocratic_ leader fascist_ state communist_ dictatorship 2004, G.Tecuci, Learning Agents Center government_ of_USSRy_1943 theocratic_ government religious_ dictatorship government_ of_Germany_1943 theocratic_ democracy chief_and_ tribal_council Political factors: Controlling elements controlling_element controlling_leader other_controlling_element people god_king monarch other_ controlling_ leader controlling_organization ceo religious_leader military_leader Secret_police para_military_ group_leader controlling_group political_leader head_of_state head_of_government religious_body military_staff dominant_clan_leader 2004, G.Tecuci, Learning Agents Center Ruling_political_party clan_leader political_cabinet_ or_staff Conventional_ law_enforcement_ organization Governing and controlling elements democratic_ government representative_ democracy government_ of_US_1943 has_as_head_ of_government has_as_legislative_body has_critical_role_in_ President_Roosevelt setting_objectives_for Congress_of_US has_critical_role_in_ decision_making_for has_as_ruling_political_party Democratic_Party has_as_dominant_psychosocial_factor parliamentary_ democracy will_of_the_people_ of_US_1943 has_as_governing_body has_as_dominant_psychosocial_factor will_of_the_parliament_ of_Britain_1943 has_as_head_ of_government Winston_Churchill government_ has_as_political_cabinet_or_staff War_cabinet of_Britain_1943 has_as_legislative_body parliament_of_Britain_1943 2004, G.Tecuci, Learning Agents Center US_1943 Governing and controlling elements (cont.) head_of_government fascist_ state has_as_head_ of_government Adolph_Hitler has_as_ruling_political_party government_of _Germany_1943 has_as_secret_police Nazi Party Gestapo has_as_military_staff OKW 2004, G.Tecuci, Learning Agents Center Other objects object resource_or_ infrastructure_element resource raw_material strategically_essential_resource_ or_infrastructure_element product Strategic_raw_material Oil_chromium_copper_ bauxite_of_Germany_1943 strategically_essential_ infrastructure_element main_airport sole_airport drugs strategically_essential_ goods_or_materiel main_seaport war_materiel fuel sole_seaport essential_campaign_war_materiel 2004, G.Tecuci, Learning Agents Center landing_craft_and_fighter_aircraft_of_US_1943 farmimplements The feature hierarchy Overall organization Informal descriptions Goals Component of Economic factors Controlling factors Geographic factors Other relevant factors 2004, G.Tecuci, Learning Agents Center Overall organization of the feature hierarchy feature D: object R: object informal_specification D: object R: any string … has_as_governing_body D: force R: agent has_as_opposing_force D: scenario R: force has_as_force_goal D: force R: force_goal has_as_controlling_element D: agent R: agent … has_as_component D: force R: force … 2004, G.Tecuci, Learning Agents Center … has_as_economic_factor D: force R: economic_factor … Overall organization of the feature hierarchy (cont.) feature D: object R: object type_of_operations D: force R: {“independent operations” “joint operations” “combined operations” “combined and joint operations”} has_as_dominant_psychosocial_factor D: governing_body R: will_of_agent has_critical_role_in_activity_for D: controlling_element R: force … has_as_primary_force_element D: force R: force 2004, G.Tecuci, Learning Agents Center has_as_dominant_partner D: force R: force has_as_additional_relevant_factor D: force R: strategic_cog_relevant_factor … has_as_geographic_center_of_power D: force R: place … has_as_source_of_strength_power_and_resistance D: force R: strategic_cog_relevant_factor Overall organization of the feature hierarchy (cont.) feature D: object R: object is_critical_to_the_production_of D: resource R: product is_obtained_from D: resource R: object controls D: economic_factor R: resource_ or_infrastructure_element produces D: agent R: product generates_essential_war_materiel_from_the_strategic_perspective_of D: industrial_capacity R: force 2004, G.Tecuci, Learning Agents Center Informal descriptions informal_specification D: object R: any string brief_description D: object R: any string 2004, G.Tecuci, Learning Agents Center description D: object R: any string documentation D: object R: any string Goals has_as_force_goal D: force R: force_goal has_as_strategic_goal D: force R: force_goal 2004, G.Tecuci, Learning Agents Center has_as_theater_strategic_goal D: force R: force_goal has_as_operational_goal D: force R: force_goal Component of has_as_component D: force R: force component_state D: force R: single_state_force has_as_first_member D: multi_member_force R: force 2004, G.Tecuci, Learning Agents Center has_as_member D: multi_member_force R: force has_as_second_member D: multi_member_force R: force has_as_subgroup D: force R: group has_as_third_member D: multi_member_force R: force has_as_additional_member D: multi_member_force R: force Economic factors has_as_economic_factor D: force R: economic_factor has_as_commerce_authority D: force R: economic_factor has_as_strategic_raw_material D: force R: raw_material has_as_economy D: force R: type_of_economy has_as_information_network_or_system D: force R: economic_factor has_as_transportation_factor D: force R: economic_factor … has_as_industrial_factor D: force R: economic_factor has_as_industrial_authority D: force R: economic_factor 2004, G.Tecuci, Learning Agents Center Economic factors (cont.) has_as_transportation_factor D: force R: economic_factor has_as_transportation_network_or_system D: force R: economic_factor 2004, G.Tecuci, Learning Agents Center has_as_transportation_center D: force R: economic_factor Controlling factors has_as_controlling_element D: agent R: agent has_as_controlling_leader D: agent R: person has_as_controlling_organization D: agent R: agent … … has_as_controlling_group D: agent R: agent … 2004, G.Tecuci, Learning Agents Center Controlling factors (cont.) has_as_controlling_leader D: agent R: person has_as_religious_leader D: governing_body R: person has_as_god_king D: governing_body R: person has_as_monarch D: governing_body R: person has_as_military_leader D: governing_body R: person has_as_political_leader D: governing_body R: person has_as_head_of_government D: governing_body R: person 2004, G.Tecuci, Learning Agents Center has_as_commander_in_chief D: force R: person has_as_head_of_state D: governing_body R: person Controlling factors (cont.) has_as_controlling_group D: agent R: agent has_as_military_staff D: governing_body R: agent has_as_political_cabinet_or_staff D: governing_body R: agent has_as_religious_body D: governing_body R: agent 2004, G.Tecuci, Learning Agents Center Controlling factors (cont.) has_as_controlling_organization D: agent R: agent has_as_ruling_political_party D: governing_body R: agent has_as_legislative_body D: agent R: agent 2004, G.Tecuci, Learning Agents Center has_as_secret_police D: governing_body R: agent has_as_religious_organization D: agent R: agent has_as_conventional_law_enforcement_organization D: governing_body R: agent Controlling factors (cont.) has_critical_role_in_activity_for D: controlling_element R: force has_critical_role_in_decision_making_for D: controlling_element R: force 2004, G.Tecuci, Learning Agents Center has_critical_role_in_setting_objectives_for D: controlling_element R: force Geographic factors has_as_geographic_center_of_power D: force R: place has_as_capital D: force R: place 2004, G.Tecuci, Learning Agents Center has_as_other_geographic_center_of_power D: force R: place Other relevant factors has_as_additional_relevant_factor D: force R: strategic_cog_relevant_factor has_as_other_relevant_factor D: Force R: Other_relevant_factor has_as_other_demographic_factor D: force R: demographic_factor has_as_other_political_factor D: force R: political_factor has_as_other_economic_factor D: force R: economic_factor has_as_other_military_factor D: force R: military_factor has_as_other_geographic_factor D: force R: geographic_factor has_as_other_historic_factor D: force R: historic_factor has_as_other_psychosocial_factor D: force R: psychosocial_factor has_as_other_international_factor D: force R: international_factor 2004, G.Tecuci, Learning Agents Center Overview Semantic networks Ontology representation Reasoning with an ontology Development and maintenance of an ontology Sample ontology for COG analysis Ontology development tools Exercises and readings 2004, G.Tecuci, Learning Agents Center KB Management and Ontology Tools Object Hierarchy Browsers Ontology Tools Feature Hierarchy Browsers Object Editor Association Browser Feature Editor Object Viewer Script Editor Feature Viewer Knowledge Base Management Ontology Management Plausible Version Spaces Mngt. ONTOLOGY 2004, G.Tecuci, Learning Agents Center Rules Management RULES These are tools for a knowledge engineer, primarily to develop and update the object ontology. Association browser 2004, G.Tecuci, Learning Agents Center Object hierarchy browser and object viewer 2004, G.Tecuci, Learning Agents Center Feature hierarchy browser and Feature viewer 2004, G.Tecuci, Learning Agents Center Object editor 2004, G.Tecuci, Learning Agents Center Overview Semantic networks Ontology representation Reasoning with an ontology Development and maintenance of an ontology Sample ontology for COG analysis Ontology development tools Exercises and readings 2004, G.Tecuci, Learning Agents Center Exercise Develop an object ontology that represents the following information: Birds have feathers, fly and lay eggs. Albatros is a bird. Donald is a bird. Tracy is an albatros. You should define object concepts, object features and instances. 2004, G.Tecuci, Learning Agents Center Exercise Develop an object ontology that represents the following information: Puss is a calico. Herb is a tuna. Charlie is a tuna. All tunas are fishes. All calicos are cats. Cats like to eat fishes. You should define object concepts, object features and instances. 2004, G.Tecuci, Learning Agents Center Exercise Develop an object ontology that represents the following information: The color of Apple1 is red. The color of Apple2 is green. Apple1 is an apple. Apple2 is an apple. Apples are fruits. You should define object concepts, object features and instances. 2004, G.Tecuci, Learning Agents Center Exercise Develop an object ontology that represents the following information: Basketball players are tall. Muresan is a basketball player. Muresan is tall. You should define object concepts, object features and instances. 2004, G.Tecuci, Learning Agents Center Exercise Insert the additional knowledge that platypus lays eggs into the following object ontology: birth-mode mammal subclass-of subclass-of cow Explain the result. 2004, G.Tecuci, Learning Agents Center platypus live Exercise Consider the question: “Is there a part of a loudspeaker that is made of metal?” In the context of the following object ontology. a) Which are all the answers to this question? b) Which are the reasoning operations that need to be performed in order to answer this question. c) Consider one of the answers that requires all these operations and show how the answer is found. SOMETHING ISA I N F L A M M-O A BBLJEE C T ... ISA ISA ISA ADHESIVE ... ISA ISA M A T E R I A L F R A G-O I LB J E C T TOXI -SCU B S T A N C E ISA ISA GLUES M O W I C OSLTLA T Ef l u i d PROVIDER ... ISA ISA GLUES ISA M A D E - OMFE M B R A N E ISA PAPER I N S T A -O N C F E COLOR M E M B R1A N E black PART-OF C O N T A-ACDTH E S I V EI S A GLUES GLUES I N S T A-O N CFE M O W I C1O L L GL U-EIN C 2004, G.Tecuci, Learning Agents Center GLUES PROVIDER GLUES PART-OF L O U D S P E-C A KOEMRP O N E N T ISA ISA ISA LOUDSPEAKER ISA METAL MECHANI -CCHAALS S I S C H A S S-I S M E M B R-A N E ASSEMBLY ISA I N S T A-O N CFE CONTAINS MADE-OF I N S T A-O N CFE ISA MECHANI -CCHAALS S1I S ISA I N S T A-O N CFE ISA C H A S S-I S M E M B R-A N E A S S E M1B L Y MADE-OF MADE-OF C A O U T C H OC UO C N T A-ACDTH E S1I V E BOLT C H A S S-AISSS E M B L Y PART-OF I N S T A-O N CFE I N S T A-O N CFE C H A S S-AISSS E M1B L Y B O L1T Recommended reading Tecuci G., Lecture Notes on Semantic Networks (on the course web site) Tecuci G., Building Intelligent Agents, Academic Press, 1998, pp. 33-78. Gruber T., What is an ontology, http://www-ksl.stanford.edu/kst/what-is-anontology.html (accessed September 29, 2003). Stanescu B., Boicu C., Balan G., Barbulescu M., Boicu M., Tecuci G., "Ontologies for Learning Agents: Problems, Solutions and Directions," in Proceedings of the IJCAI-03 Workshop on Workshop on Ontologies and Distributed Systems, Acapulco, Mexico, August, AAAI Press, Menlo Park, CA, 2003, pp. 75-82. http://lac.gmu.edu/publications/data/2003/stanescu-gmu.pdf Boicu M., Tecuci G., Stanescu B., Balan G.C. and Popovici E., Ontologies and the Knowledge Acquisition Bottleneck, in Proceedings of IJCAI-2001 Workshop on Ontologies and Information Sharing, Seattle, Washington, August 2001. http://lac.gmu.edu/publications/data/2001/ontbottleneck.pdf Boicu M., Tecuci G., Bowman M., Marcu D., Lee S.W. and Wright K., A ProblemOriented Approach to Ontology Creation and Maintenance, in The Sixteenth National Conference on Artificial Intelligence (AAAI-99) Workshop on "Ontology Management", July 18-19, Orlando, Florida, AAAI Press, Menlo Park, CA. 1999. http://lac.gmu.edu/publications/default.htm 2004, G.Tecuci, Learning Agents Center