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Herbal Tutorial - Applied Cognitive Science Lab

1. 37 iii 9 May 2005 1 0 What is Herbal Cognitive architectures are useful to a wide variety of users Computer scientists psychologists cognitive scientists and various domain experts can all use cognitive architectures Unfortunately designing implementing and using cognitive architectures can be a difficult task considering that the background and expertise of this diverse set of users varies from novice to expert In addition the tasks performed by users of such architectures can vary considerably and can include a wide variety of tasks Further discussion of this problem of usability is available in Ritter et al 2003 To accommodate the wide range of users and to promote the use of cognitive systems development environments allow the modeler to focus more on the problem domain and less on the details of a particular architecture This tutorial introduces an integrated development environment called Herbal Cohen Ritter amp Haynes 2005 Morgan Cohen Haynes amp Ritter 2005 Morgan Ritter Cohen Stevenson amp Schenck 2005 that acts as a first step towards creating development tools that support the wide range of users of cognitive models With it users can create models graphically and have these models compiled into Soar productions The productions will work as any Soar model does The structure of the model can be passed to an associated tool that can help display and expl
2. Block 3 OnTop Herbal How it works Table 1 Herbal Purpose Clear true Type 88 Block cn Figure 13 Block instances 9 Classes Slots Forms Instances 4 Queries Model Attributes ver 0 9b Herbal Compiler ver 0 9b M INSTANCE BROWSER M INSTANCE EDITOR For Project blocksWorld 0 9b For Class 9 OnTop Class Hierarchy ALR Xx 7 HerbakName THING onTopof AOnTopOf SYSTEM CLASS BOnTopOf 9 herbal HerbalClass COnTopof Herbat Definition herbal Expression relationship that specifies what block Ais on top of herbal Model 1 herbal PSCM herbal iMObject Block 3 OnTop 3 Herbal How it works Table 1 HerbakPurpose Bottom AU Table kal Tl I Top Ue LUE S IE Ra e Figure 14 OnTop instances 14 9 May 2005 Classes Slots Forms Instances Queries Model Attributes ver 0 9b Herbal Compiler ver 0 9b CLASS BROWSER M INSTANCE BROWSER M INSTANCE EDITOR blocksWorld 0 9b Table Table instance of Table internal name is blocks x X AP S Ox Table Table A tabl OnTop 3 Table tru 4 ul J via vi Tabl v Figure 15 Table instance 4 6 Creating the Top State With the domain knowledge
3. Elaborations have conditions and actions and in fact conditions and actions can be shared by and across operators and elaborations To create the GoalStateReached elaboration follow these steps 1 Make sure the Instances tab is selected and expand the herbal HerbalClass node and then the herbal Production node in the instances tree 2 Create a new herbal Elaboration object and assign the following attributes 26 9 May 2005 Herbal Name GoalStateReached Herbal Definition Terminates the simulation if block A is on top of block B and block B is on top of block C and block C is on top of the table Again somewhat like operators elaborations have conditions and actions The GoalStateReached elaboration will have a single condition IsGoalReached and a single action Done These conditions and actions are created in the same fashion as the conditions and actions we already created for the operators aside from one exception the Herbal Operator memory attributes are ignored for conditions and actions that are assigned to an elaboration This is because elaborations are not proposed like operators but are immediately applied instead this is reflected in that the chane in Soar are either O or I supported As a result it is not necessary to specify what matched objects will be remembered The completed TIsGoalReached condition and Done action are shown in Figures 24 and 2
4. blocks Clear true blocks Type Block herbal Definition A block with the letter A printed on it herbal Name A lt BOnTopOf gt herbal Definition A relationship that specifies block B is on top of herbal Name BOnTopOf blocks Bottom lt Table gt blocks Top lt B gt lt B gt blocks Clear true blocks Type Block herbal Definition A block with the letter B printed on it herbal Name B lt COnTopOf gt herbal Definition A relationship that specifies block C is on top of herbal Name COnTopOf blocks Bottom lt Table gt blocks Top lt C gt c blocks Clear true blocks Type Block herbal Definition A block with the letter C printed on it herbal Name C Listing 1 Soar code created by Herbal showing how working memory elements are attached to the top state 4 8 Creating the MoveBlockToTable Operator and Assigning it to the Top State The simple blocks world solution that will be implemented in this tutorial consists of two operators and one elaboration The two operators are MoveBlockToTable and MoveBlockToBlock The MoveBlockToTable operator checks the top state to see if there is a clear block that is currently not on the table and if there is a clear spot on the table If these conditions are satisfied the block is moved to the table 1 9 May 2005 The MoveBlockToBlock operator checks the top state to see if there are two clear blocks
5. ierbal Expression ierbal Model o ierbal PSCM erbalWhMObhject Block OnTop Table Figure 9 Creating new working memory objects 3 The next step is to assign attributes to these new classes You should be familiar with the task of assigning attributes from the Prot g tutorial Because these new classes are subclasses of herbal WMObject each class will automatically inherit the herbal Name herbal Definition herbal How it works and herbal Purpose attributes However you will need to add the attributes shown in Figures 10 12 to the Block Table and OnTop classes Prot g Tip Prot g does not allow you to create two attributes with the same name As a result classes that have similar attributes will be sharing the attributes they have in common To accomplish this you must use the create button to create an attribute the first time However from that point on you can reuse the attribute with other classes by clicking on the add button For example both the Block class and the Table class require an attribute named Clear You only have to create that attribute once using the create button and then reuse it in the Table class by using the add button ing ing ng ing Block Name Cardinality m Clear single String herbal Definition required single Str herbal How it works single Str herbal Name required single Str herbal Purpose single Str m Type single St
6. Tony Kalus and collectively the students of IST402 have helped improve this manual Discussions with SoarTech have influenced our thinking and they provided support for the study of their SAP that gave rise to some of the results during this work Steve Haynes and Isaac Council helped develop Herbal Table of Contents 1 0 Whatis Hetbal 2 ege a eee ee ee A oerte eee 1 2 0 Installing the Required Software 0 ec ieeeeseeseeseseceeeseeseesceeceeseeseeecscesesseesceessessessesasessessesaeeasesseeseeaseaseeens 1 2 Melinstall Protege naian ee jek ELA MLSE Ease Bea Stet RHEIN alas Bee sade dad e 1 2 2 Install the RDF Prot g Plug in oo cee ec sessi tnnt nnt nne nne nente enne nennen nennen 2 2 3 Install Herbal ener rene re e dee e eq ee EE OR edet 3 3 0 Learning Prot g norde eee eee e RE E ER PAR ERE ERN RU B ure RR Eee Pe 3 4 0 Creating a Blocks World Model 5 rient eter ea ti iere e re eR eae een ed 4 4 1 Creating a New Herbal Project aka a Prot g Project sss nenne 4 4 2 Including the Herbal Soar Ontology essent enne tne nennen tnn nnns 6 4 3 Setting the Model AttribUtes odi d dedi aet e e di e dedi 8 4 4 Classifying Domain Specific Knowledge eese teens 8 4 5 Instantiating Domain Specific Knowledge sese nen eene 11 4 6 Creating the Top States etie e nee eani te iei He ere ne e rie ies 15 4 7 Assigning Initial Working Memory to the Top
7. editing the top state You 15 9 May 2005 can use the Forms tab in Prot g to arrange the display of the form to your liking The right hand side of Figure 15 for example can be modified to display the Type above the Clear or to display the Description last Prot g Tip Once again you may wish or need to arrange these forms in Prot g using the Prot g Forms tab Don t forget you may also have to change the data entry control type to TextAreaWidget for fields that allow for multi line text entry 4 7 Assigning Initial Working Memory to the Top State Creating the rest of the blocks world model consists of filling in the attributes of the top state This includes the state s initial working memory elaborations and operators To add initial working memory to the top state follow these steps Prot g Tip Once again when filling in the attributes you may need to arrange the forms in Prot g using the Prot g Forms tab Don t forget you may also have to change the data entry control type to TextAreaWidget for fields that allow for multi line text entry 1 All of the instances of domain knowledge created earlier are possible candidates for a state s initial working memory For the blocks world model all three blocks the table and the three OnTop relationships should be included in the initial working memory for the top state Adding these working memory elements is a simple task ju
8. exercise you are encouraged to try this on your own However for your reference these two operators are included in the Block World Model that is part of the Herbal distribution If you need help you are encouraged to browse this model to see how these operators were created and then attempt to reproduce these operators in your Blocks World Model 7 0 The Herbal dTank Model The Herbal distribution also contains a more interesting and complex model for use with the Java based dTank game acs ist psu edu dTank created by the Applied Cognitive Science Lab at the Pennsylvania State University Morgan Ritter et al 2005 Once you have completed this tutorial and are familiar with the Herbal IDE and High level Language you may want to experiment with the dTank model The Herbal dTank model is located in the Herbal installation directory in a folder called htank Before you work with this model you should familiarize yourself with dTank by reading the dTank User s Manual Isaac G Council Morgan amp Ritter 2004 Once you are familiar with dTank you can view edit or compile the dTank Herbal model using the same skills learned in this tutorial The relative complexity of the dTank model relative to Blocks World makes it easier to see the advantages made possible by using the Herbal IDE To illustrate these advantages a brief summary of the structure of the dTank model is given in the following sections 7 1 Summary of the dT
9. see the tab appear as the last tab in the main Prot g window within a few seconds Figure 7 If you still don t see the ModelAttributesTab restart Prot g The fields located on the Model Attributes tab should be populated before the rest of the model is defined Take the time now to populate these fields similar to what is shown in Figure 7 El blocksWorld 0 9b Prot g 3 0 _ file C Documents 20and 20Settings mcohen My 20Documents Dey m File Edit Project Window Help Alesa i yal Ie m ex prot g instances a Queries Model Attributes ver 0 9b Herbal Compiler ver 0 9b l i f Classes r Slots I Forms Name Blocks World Model Original Author Mark A Cohen Creation Date 06 01 2004 Last Updated 05 06 2005 Definition Purpose The purpose ofthis model is to arrange three blocks on a table ina specified order How it works Design Constraints None Figure 7 The model attributes tab 4 4 Classifying Domain Specific Knowledge The next step in the model creation process is to define and instantiate model knowledge For this particular model we are going to define three different classes of knowledge Block 8 9 May 2005 Table and OnTop These classes and their attributes come directly from the Soar User s Guide Laird et al 1999 The first two classes are self explanatory the third OnTop will be us
10. 5 M INSTANCE EDITOR For Instance IsGoalReached instance of herbal Condition internal name is N x X a Herbal Name Herbal Exp IsGoalReached ar true Table Herbal Definition on BlockB BlockB is on BlockC and BlockC is on the table Herbal StateMatches B herbal WorkingMemory BOnC herbal orkingMemory BlockC WorkingMemory lt COnTable gt orkingMemory Table CO A orkingMemc ka ocko A herbalorkingMemory lt AOnB s iiia herbal vorkingMemory lt BlackA BlockB m BlockC Herbal OperatorMemory B Figure 24 The complete IsGoalReached condition 27 9 May 2005 k INSTANCE EDITOR For Instance Done instance of herbal Action internal name is bl X X a Herbal Name Done Herbal Definition Notifies user that goal was reached and system is halted Herbal OperatorMemory Herbal Exp write Goal Reached p halt Figure 25 The Done action 4 Finally don t forget to assign the IsGoalReached condition and Done action to the GoalStateReached elaboration and then assign the GoalStateReached elaboration to the top state The completed GoalStateReached elaboration is shown in Figure 26 and the generated elaboration production is shown in Listing 5 M INSTANCE EDITOR For Instance 4 GoalStateReached insta
11. For example you could create an operator that turns on the tank s shields if it is near death or under fire 36 9 May 2005 2 Make the model more or less aggressive by modifying preferences on some of the operators 3 Write a Tcl Tk function that calculates the angle between two points and then utilize this function in a new operator that aims the turret towards an enemy HINT the basic tank that comes with the dTank distribution contains such a function 4 Write an operator that recognizes nearby stones and remembers them by adding their location to working memory You can then utilize this information to avoid or find stones later on 8 0 Summary The Herbal High level Language and IDE are still being developed As a result you will find some bugs and some functionality missing For example currently the language does not support more than just a single top level state The time and effort you spend experimenting with Herbal is greatly appreciated and your feedback is very important If you have any questions or would like to report a bug please contact Mark Cohen via email at mcohen lhup edu In addition at this stage in development we might not be able to support backwards compatibility between models created with older versions of Herbal As a result if you create a model using the current version of Herbal we ask that you do not expect your model to work with future releases of Herbal It is possible that changes will be
12. Herbal dTank model also contains many of the common actions that are performed by a tank operating in the dTank environment These actions are used by the Herbal model to operate the tank as a consequence of operator applications Once again the same type of inter model reuse can be achieved by sharing these actions in the Herbal operators A list of the actions included in the dTank model along with the operators that share them can be seen in Table 11 Table 11 A summary of the actions used in the Herbal dTank Model and how these actions are shared by operators Action Used By Fire move forward removeCommand rotate turret down rotate turret up setWait Turn 35 Fire move left move right remove commands aim down aim up Wait turn left turn right 9 May 2005 7 2 A Summary of Herbal s Documentation Capabilities In addition to promoting reuse the Herbal Tank model also demonstrates Herbal s documentation capabilities Every class in the Herbal High Level Language Ontology contains explanation oriented fields such as definition how it works and purpose These fields filled in during model creation are used by Herbal to generate useful documentation in the generated Soar productions For example as shown in Listing 6 the production that proposes that the tank move right contains a comment that was automatically generated by Herbal using the explanation oriented fields discussed above Productio
13. PENNSTATE o lST SCHOOL OF INFORMATION SCIENCES AND TECHNOLOGY THE PENNSYLVANIA STATE UNIVERSITY Herbal Tutorial Supports version 0 9b of the Herbal IDE Mark A Cohen and Frank E Ritter Technical Report No ACS 2004 2 9 May 2005 mcohen C hup edu frank ritter psu edu Phone 1 814 865 4455 Fax 1 814 865 6426 School of IST 319 IST Building University Park PA 16802 Herbal Tutorial Mark A Cohen and Frank E Ritter mcohen lhup edu _ritter ist psu edu School of Information Sciences and Technology The Pennsylvania State University University Park PA 16801 3857 ACS 2004 2 9 May 2005 Abstract To accommodate this wide range of users and to promote the use of cognitive systems it is essential that tools such as high level languages and development environments are created to allow the modeler to focus more on the problem domain and less on the nuances of a particular architecture This tutorial introduces an integrated development environment and high level behavior representation language called Herbal that represents a step towards creating tools to support a wide range of cognitive model users This tutorial instructs users how to install Herbal and describes how to develop two models including a blocks world model and a dTank model Acknowledgements The research was supported by the Office of Naval Research contract N000140210021 Comments from Isaac Council Bill Stevenson Geoff Morgan Urmila Kukreja
14. State 16 4 8 Creating the MoveBlockToTable Operator and Assigning it to the Top State 17 4 9 Creating the MoveBlockToBlock Operator and Assigning it to the Top State 23 4 10 Creating the GoalStateReached Elaboration and Assigning it to the Top State s 26 5 0 Compiling the Blocks World Model esses ener nne nnne nne nennen enne 29 5 1 Including Custom Code in Your Model essent enne nnne nennen 30 6 0 Impasses and Child States sss eene tnnt nnne tnnt ennt nennen tnter nens 31 6 1 Generating an Operator Tie Impasse ceccesceseescesecsseeseeseesecsececeesecsecsecceesecaecseceeeeaecseceeeeaeeaeeeeeeeeaees 31 6 2 Creating an Herbal Child State esee ener nennen nnenne nnne 31 6 3 Creating an Herbal Impasse s 0 ccss cescdegeivseceedi sede nni ech oles eere rede di ee Eae a nte een 32 6 4 Creating Operators that Resolve the Tie essent ennt tnt nnn 32 7 0 The Herbal d Tank Model eese nennen nennen nne tente ene tenete enne tne tentent tneneens 33 7 1 Summary of the dTank Model and How it Promotes Reuse esee 33 7 2 A Summary of Herbal s Documentation Capabilities eese 36 7 3 How to Execute the Generated Herbal dTank Model eese 36 7 4 Suggestions for Expanding the Model esses eterne nnne enne nnn 36 SO SUM AY EE
15. Table 1 Files in the Herbal Distribution X represents the version number These files can be found in your Herbal installation folder Herbal Prot g Files herbal X pprj herbal X rdf herbal X rdfs herbalWidgets jar Herbal Compiler Files herbal X xslt Blocks World Example Files blocksWorld X pprj blocksWorld X rdf blocksWorld X rdfs b To complete the installation move herbalWidgets jar into the Prot g plugins folder The Prot g plugins folder is located inside the Prot g installation folder typically Protege VERSION plugins You must restart Prot g for these changes to take effect 3 0 Learning Prot g In order to use Herbal it is essential that you have a basic understanding of Prot g because Herbal uses Prot g for its interface The best way to learn Prot g is to follow the Prot g tutorial To start the tutorial run Prot g and click on the Getting Started button located on the Prot g open project dialog Figure 2 This will launch a browser containing the Prot g tutorial You can also get to the tutorial by going directly to protege stanford edu doc tutorial get started Note the current 3 0 Prot g tutorial uses screen shots from Prot g 2 3 9 May 2005 After completing the Prot g tutorial it is a good idea to keep the Prot g user s guide Stanford Medical Informatics 2003 close by The user s guide can be accessed by running Prot g and cl
16. Table 5 Attributes for the table object Herbal Name Table Herbal Definition A table Clear true Type Table Height 10 Table 6 Attributes for the AOnTopOf relationship object Herbal Name AOnTopOf Herbal Definition A relationship that specifies what A is on top of Bottom Table Top A Table 7 Attributes for the BOnTopOf relationship object Herbal Name BOnTopOf Herbal Definition A relationship that specifies what B is on top of Bottom Table Top B Table 8 Attributes for the COnTopOf relationship object Herbal Name COnTopOf Herbal Definition A relationship that specifies what C is on top of Bottom Table Top C 3 When you are done instantiating your knowledge your instance hierarchy should resemble Figures 13 14 and 15 13 9 May 2005 Classes Slots Forms Instances CLASS BROWSER M INSTANCE BROWSER M INSTANCE EDITOR For Project blocksWorld 0 9b For Class 6 Block Queries Model Attributes ver 0 9b Herbal Compiler ver 0 9b For Instance 9 A stance of Block internal name is blocksWo D Class Hierarchy P Vz X 7 nerbatName THING ea A SYSTEM CLASS B herbal HerbalClass c Herbal Definition o herbal Expression JA block with the letter A printed on it herbal Model 1 herbal PSCM herbal WMObject
17. ain the model even as the model runs This document also starts to describe a programming style for Herbal in the same way as the Soar manual Laird Congdon amp Coulter 1999 and the Soar Dogma document Nuxoll amp Laird 2003 The design of Herbal is based on a study done with SoarTech s SAP about what questions users ask of a model as well as an analysis of explanation and explanation types from that broad literature Council Haynes amp Ritter 2003 Haynes Ritter Council amp Cohen submitted 2 0 Installing the Required Software The Herbal IDE is built upon and leverages several pieces of software These systems must be installed before you can begin using Herbal The following section lists the required software along with installation instructions 2 1 Install Prot g The first step towards getting Herbal installed and running is to download and install Prot g Stanford Medical Informatics 2004 Prot g is a graphical ontology editor created and maintained by Stanford Medical Informatics Herbal is thus programmed by defining the model in Prot g The tool is available for free under the Mozilla Public License Mozilla 2004 and can be downloaded from protege stanford edu Because Prot g is written in Java it will run on any platform that supports a version 1 4 2 or higher Java Virtual Machine this includes Windows XP Linux and Macintosh machines 1 9 May 2005 When you download the P
18. al step to creating a condition is to specify what match variables should be made available to the operator that is using this condition and this is done using the Herbal OperatorMemory attribute This makes it possible to later alter any of the objects referenced by these variables When we create the action in the next step the action responsible for actually moving the block to the table we will see how the Herbal OperatorMemory attribute is used For now you can just specify that the block table OnTop relationship and the current bottom block should be remembered after this condition matches the current situation Adding this condition to the MoveBlockToTable operator will result in the creation of the Soar operator proposal shown in Listing 2 Notice that the objects specified in the Herbal OperatorMemory attribute are attached to the operator when it is proposed sp propose MoveBlockToTable state s herbal Name BlocksWorldState herbal WorkingMemory lt Block gt herbal WorkingMemory lt OnTop gt herbal WorkingMemory lt Table gt lt Block gt blocks Clear true blocks Type Block lt Table gt blocks Clear true blocks Type Table lt OnTop gt blocks Bottom lt gt lt Table gt blocks Top lt Block gt blocks Bottom lt CurrentBottomBlock gt gt lt s gt operator lt o gt lt o gt name MoveBlockToTable Block lt Block gt Curren
19. and that the first clear block is not on top of the second clear block If these conditions are satisfied the first block is put on top of the second block Creating these two operators in Herbal consists of instantiating two herbal Operator objects and assigning them to the top state The following steps describe this process l Make sure the Instances tab is selected and expand the herbal HerbalClass node and then the herbal Production node in the instances tree Create a new herbal Operator object and assign the following attributes Herbal Name MoveBlockToTable Herbal Definition Moves a clear block onto a clear table Herbal Preference Indifferent Once the operator object is created the next step is to create and assign the conditions that will cause the operator to be proposed This is done by instantiating herbal Condition objects Each herbal Operator object can have one or more conditions assigned to it If more than one condition is assigned to an operator the conditions are combined using a logical AND Because the MoveBlockToTable operator should be proposed when a clear block and a clear table exists we need to create a condition object that matches this situation To create a new condition object click on the create button shown below in Figure 17 next to the operators Herbal Conditions attribute INSTANCE BROWSER herbal Condition A We eX Figure 17 Cre
20. and the BlocksTutorial project consisting of three files BlocksTutorial pprj BlocksTutorial rdfs and BlocksTutorial rdf will be saved in your BlocksTutorial folder pprj stands for Prot g project Prot g Tip Each new project consists of three related files the pprj file the rdf file and the rdfs file The pprj file is the Prot g project file The rdf and rdfs files contain your model s definition in RDF format These files along with the Herbal pprj rdf rdfs and xslt the compiler definition file files must remain in the same directory Do not copy or otherwise move these files to different locations or else Prot g will have trouble finding them later In addition all of these files are required by the project so if you wish to backup move or email a project someone else you need to include all of the files in your project directory 4 2 Including the Herbal Soar Ontology Before you can start creating knowledge states operators and elaborations you must include the Herbal Soar Ontology This ontology was also created using Prot g and the RDF plug in and is defined in the following three files herbal X pprj herbal X rdf and herbal X rdfs These files will be located in your BlocksTutorial folder 6 9 May 2005 The Herbal Soar Ontology should be included in your project by performing the following steps 1 From the Project menu select the Include Project menu ite
21. ank Model and How it Promotes Reuse The Herbal dTank model consists of a single top state that contains eight operators and one elaboration The elaboration named remove commands is necessary in order to remove action commands that are placed on the Soar output link once they have been executed AII dTank models require this elaboration and Herbal makes it very easy to reuse this elaboration across models The eight operators that are included in the Herbal dTank model are summarized in Table 9 These operators can be reused across models simply by importing the operators and their components into a new Herbal dTank model or by creating a new Prot g project based on the htank project 33 9 May 2005 Table 9 A Summary of the Herbal dTank Operators Name Purpose turn left If an enemy tank is spotted to my left and my tank is not facing left turn left turn right If an enemy tank is spotted to my right and my tank is not facing right turn right move left If an enemy tank is spotted to my left and my tank is facing left move forward one space move right If an enemy tank is spotted to my right and my tank is facing right move forward one space Wait If there is no information to act on wait until my sensors report something aim down If there is not enemy tank seen and my turret is facing up rotate it down to look for an enemy aim up If there is not enemy tank seen and my turret is facing down rotate it up
22. ating a new condition 4 When the new condition dialog box is displayed you should assign the new condition the attributes shown in Figure 18 Prot g Tip Once again when filling in the attributes you may need to arrange the forms in Prot g using the Prot g Forms tab Don t forget you may also have to change the data entry control type to TextAreaWidget for fields that allow for multi line text entry 18 9 May 2005 INSTANCE EDITOR or Instar ClearBlockClearTable instance of herbal Condition internal name is bl N X X ClearBlockClearTable lear true pe Blockp Ifthere is a clear block ontop of another block and the ocks Clear true table is clear me Tablel ottom lt gt Table blocks Top Block blocks Bottom CurrentBottomBlock R h erbalWorkingMemory lt OnTop herbal WWorkingMemory Table herbalWorkingMemory Blocks I E CurrentBottomBlock lt OnTop lt Table Blacks 4 gt Figure 18 ClearBlockClearTable condition To better understand how a condition object works the attributes in this dialog box should be explained in more detail The herbal Name and herbal Definition are self explanatory so we should start the herbal StateMatches attribute The herbal StateMatches attribute allows the model designer to specify what objects should be searched for as working memory elements on the state asso
23. bal IDE is to run Prot g and create a new RDF Schema based project This can be accomplished by performing the following steps 1 Create a new folder called BlocksTutorial and copy the herbal X xslt herbal X pprj herbal X rdf and herbal X rdfs files from your Herbal installation folder into this new folder again X represents the Herbal version number This step needs to be done whenever you create a new model Installation Tip For your convenience the BlockTutorial folder is created for you and included in the Herbal distribution 4 9 May 2005 2 Run Prot g How this is accomplished may differ depending on your platform On Windows this is accomplished by double clicking on the Prot g icon See the Prot g documentation if you are having problems starting Prot g 3 You will be presented with a Prot g dialog that allows you to create new projects or open an existing project In this dialog select RDF Files and then click on New to create your Herbal project as shown in Figure 3 Protege Project Format Open Recent Help Default Files pont and pins PlocksWorld 0 9b Getting Started htank Default Database herbal 0 9b FAQ RDF Files blocksVWVorld 0 9 herbal 0 9 ERUCEAV OM seibel All Topics blocksWorld 1 0 hungryThirsty Open Other Figure 3 The New Project Dialog 4 After the new project has been created save the pr
24. ciated with the condition Because this condition will be assigned to an operator on the top state the top state will be searched for working memory elements that match the objects listed in the Herbal StateMatches attribute For this condition we are looking for a block a table and a particular OnTop relationship so we enter herbal WorkingMemory lt Block gt herbal WorkingMemory lt Table gt and herbal WorkingMemory lt OnTop gt here Of course you can match more than just Herbal working memory objects here For example matches based on the i o link can also be placed in the herbal StateMatches attribute Once you match objects on the top state you will need to specify more detail about these objects using the herbal Exp attribute The herbal Exp attribute allows us to specify more detail about the objects listed in the herbal StateMatches attribute Notice that this is done using Soar matching syntax In this case we specify that the block and the table must be clear and that the OnTop relationship must have the block on top and cannot have the table on the bottom Finally we need to remember the current bottom block matched because we are going to have to mark this block as 19 9 May 2005 covered when this operator is applied This is done by creating a new match variable CurrentBottomBlock that will be associated with OnTop relationship s current bottom block The fin
25. classified and instantiated it is possible to start defining the behavior of the model This is accomplished by instantiating objects based on the Soar ontology that was imported into the project earlier The first Soar object that should be created is the top state currently Herbal only supports the creation of a single top level state 1 Make sure the Instances tab is selected and then expand the herbal HerbalClass node then herbal PSCM and then the herbal State node in the instances tree You should see an herbal TopState class located as a subclass of the herbal State class 2 For the blocks world model you want to create a single instance of the herbal TopState class named BlocksWorldState This state has several important attributes a name and a definition as well as a list of operators elaborations and working memory Prot g Tip When creating instances of classes from the Prot g Instances tab be sure to set the display slot for the class you are going to be using The display slot specifies what attribute of your instance will be used as a label when Prot g needs to list your object If you see labels like blocksWorld Instance 30000 it means you forgot to set the display slot 3 After creating the top state object give the state a name BlocksWorldState and a definition The Blocks World Problem Space Once again you may need to customize the form used for
26. d block on top of the matched table This can be done by setting the OnTop relationship s bottom block equal to the table and by clearing the previous bottom block s flag because it is no longer covered Again notice that Soar syntax is used to specify these actions In addition notice that namespace prefixes are used to specify attributes For example a block s Clear attribute is referenced using the model s namespace prefix blocks that was assigned to the BlocksTutorial project when we originally created it with Prot g The same is true for any other namespaces that have been imported into the project For example if we wanted to match on the Herbal name attribute we would use herbal Name The MoveBlockOntoTable action will result in the generation of the Soar operator application shown in Listing 3 Sp apply MoveBlockToTable state s herbal Name BlocksWorldState operator lt o gt lt o gt name MoveBlockToTable CurrentBottomBlock lt CurrentBottomBlock gt OnTop lt OnTop gt Table lt Table gt gt lt OnTop gt blocks Bottom lt CurrentBottomBlock gt lt OnTop gt blocks Bottom lt Table gt lt CurrentBottomBlock gt blocks Clear false CurrentBottomBlock blocks Clear true Listing 3 Operator application rule generated based on the MoveBlockOntoTable action 7 The creation of the ClearBlockClearTable condition and the MoveBlockOntoTab
27. d in the previous section You can assign operators to this 31 9 May 2005 new child state that will perform actions to resolve the impasse and allow the top state to select the appropriate operator In Herbal all child states are instances of the herbal State class To handle the operator tie impasse we can create a new child state named ResolveTie This can be done from the Prot g instances tab Just highlight the herbal State class click on the create button and set the new state s name attribute to ResolveTie We will return to this state later in order to add operators that will select the appropriate operator Now that the child state created has been created in Herbal we need to create an Herbal impasse object that will create this child state when the impasse occurs 6 3 Creating an Herbal Impasse Creating an Herbal impasse that will handle the operator tie can be accomplished from the Prot g instances tab To create the impasse highlight the herbal Impasse class and click on the create button Once the impasse is created attributes need to be set that name the impasse specify its type and designate the child state that will be created when the impasse occurs In this case the child state we want to be created is the one built in the previous section The following is a summary of the required attributes for the new herbal Impasse object e herbal Name Tie e herbal ImpasseType Operator Tie e herbal SubStat
28. e ResolveTie Finally this new Tie impasse needs to be associated with the state that we expect the impasse to occur In this case this is the top state because this is the state in which the operator tie will take place This association can be accomplished by adding the Tie impasse to the Herbal Impasses attribute of the BlocksWorldState 6 4 Creating Operators that Resolve the Tie With the child state created and an impasse that will generate this new child state we are ready to add the operators that will resolve the tie and return operation to the top state as was accomplished much earlier in the tutorial using operators Therefore new operators need to be created and added to the ResolveTie state created in section 6 2 One possible implementation is to create two new operators one that generates a preference in the top state to place A on top of B and another operator that generates a preference in the top state to place B on top of C Because it is better to place B on top of C before A is placed on B a second operator should be given a best preference and the later operator an indifferent preference other combinations of preferences are possible that will accomplish the same result 32 9 May 2005 Creating these operators and adding them to the ResolveTie operator involves the same skills introduced earlier in the tutorial As a result you should already familiar with how to accomplish these tasks As an
29. e and three OnTop relationships Tables 2 8 specify the attribute values for each of the objects you will be creating you may also choose to fill in the herbal Purpose and herbal How it works fields for your objects if you wish Prot g Tip In the tables below denotes that the attribute is actually a reference to another object For example the OnTop relationship contains the Bottom and Top attribute that actually reference an instance of a block or a table Using the add button in Prot g you can select existing instances in order to populate these attributes Prot g Tip When creating new attributes for a class you may want to stick to a convention of always starting your attributes with a capital letter This is because Prot g will capitalize the first letter in attribute names automatically when displayed on a Prot g form This will help prevent confusion and prevent errors caused by incorrect case For the value true and false in particular they should be lower case Table 2 Attributes for block A Table 3 Attributes for block B Herbal Name A Herbal Name B Herbal Definition A block with the letter Herbal Definition A block with the letter B printed on it A printed on it Clear true Block Clear true Type Block Typs 12 9 May 2005 Table 4 Attributes for block C Herbal Name C A block with the letter C printed on it Herbal Definition Clear true Type Block
30. ed to specify what a block is physically on top of To define these three classes perform the following steps 1 Make sure the Classes tab is selected and expand the herbal HerbalClass node in the class tree Figure 8 These classes are part of the Herbal ontology and are often preceded by herbal namespace The Herbal compiler will often use this namespace in the generated Soar code Classes Slots Forms CLASS BROWSER blocksWorld 0 9b ff THING o SYSTEM CLASS herbal HerbalClass herbal Expression herbal Action herbal Condition herbal Model 9 herbal PSCM 2 herbal Production herbal Elaboration herbal Operator 2 herbal State herbal TopState o herbal WMObject T M I Thl Figure 8 The Herbal class hierarchy Creating new classes is a typical Prot g task and was described in the Prot g tutorial At this point you should be familiar with how to create classes All domain specific classes must be subclasses of the herbal WMObject class so be sure to create the Block Table and OnTop relationship as subclasses of herbal WMObject Don t worry about assigning attributes to these classes until the next step When you are done creating the classes the class hierarchy should look Figure 9 9 9 May 2005 Classes Slots Forms 4 CLASS BROWSER blocksWorld 0 9b THING SYSTEM CLASS herbal HerbalClass o
31. for Architectural Comparisons of Competitive Agents Paper presented at the 14th Conference on Behavior Representation in Modeling and Simulation BRIMS Universal City CA Mozilla 2004 Mozilla Public License Retrieved June 15 2004 2004 from http www mozilla org MPL MPL 1 1 html Nuxoll A amp Laird J E 2003 Soar Design Dogma from www ececs umich edu soar sitemaker docs misc dogma pdf Ritter F E Shadbolt N R Elliman D Young R Gobet F amp Baxter G D 2003 Techniques for modeling human and organization behavior in synthetic environments A supplementary review Wright Patterson Air Force Base OH Human Systems Information Analysis Center Stanford Medical Informatics 2003 Protege 2000 User s Guide User s Guide Stanford University Stanford Medical Informatics 2004 Protege Version 2 1 1 W3C 2004 Resource Description Framework from www w3 org RDF 38 9 May 2005
32. gMemory lt OnTop gt herbal WorkingMemory Block herbalWorkingMemoary Block2 Block2 lt gt Block Loss mmm Herbal OperatorMemory Block1 CurrentBottomBlock lt OnTop gt Block2 Herbal Exp Block1 blocks Clear true blocks Type Block Block27 blocks Clear true blocks Type Block OnTop blocks Bottom lt gt lt Block2 gt blocks Top lt Block1 gt blocks Bottom CurrentBottomBlock Figure 22 The complete TwoClearBlocks condition 24 9 May 2005 i INSTANCE EDITOR For Instance MoveBlock10ntoBlock2 instance of herbal A Herbal Name MoveBlock1 OntoBlock2 Herbal Definition Moves Black1 onto Block2 Herbal OperatorMemory a lt OnTop gt CurrentBottomBlack zBlock27 Herbal Exp lt Block2 gt blocks Clear true lt Block2 gt blocks Clear false OnTop blocks Bottom CurrentBottomBlock lt OnTop gt blocks Bottom Block27 CurrentBottomBlock blocks Clear false CurrentBottomBlack blocks Clear true Figure 23 The complete MoveBlock1OntoBlock2 action 25 9 May 2005 sp propose MoveBlockToBlock state lt s gt herbal Name BlocksWorldState herbal WorkingMemory lt Block1 gt herbal WorkingMemory lt Block2 gt lt Block2 gt lt gt lt Blockl gt herbal WorkingMemory lt OnTop gt lt B
33. icking on the User s Guide button located on the Prot g open project dialog Figure 2 shows how Alternatively you can access the user s guide online at protege stanford edu doc users guide Protege Project Format Open Recent Help 0 9 blocksWorld 0 9b Getting Started htank eng ae Default Database herbal 0 9b FAQ Default Files pont and pins RDF Files blocksWorld 0 9 herbal 0 9 User s Guide seibel L All Topics blocksWorld 1 0 hungryThirsty x New Build Open Other lt Q prot g Figure 2 Getting started with Prot g It is important that the Prot g tutorial is completed before the reader attempts to create Soar models using Herbal You can skip the query part however Also Macintosh users should note that option is the control key 4 0 Creating a Blocks World Model This section explains how to create a simple Soar model using Herbal The model that will be created is a simple solution to the blocks world problem presented in the Soar User s Guide Laird et al 1999 and included in most Soar distributions This problem involves stacking three blocks on top of each other The initial configuration has three blocks labeled A B and C sitting on a table The goal is to stack block A on top of block B block B on top of block C and block C should be on the table 4 1 Creating a New Herbal Project aka a Prot g Project The first step in creating a model using the Her
34. kToBlock operator are similar to the steps used to create the MoveBlockToTable operator in the previous section As a result the completed operator condition and action dialog boxes are shown in Figures 21 23 and the generated operator proposal and operator application productions are shown in Listing 4 It is left to the reader to complete these dialogs and assign the operator to the top state Prot g Tip Once again when filling in the attributes you may need to arrange the forms in Prot g using the Prot g Forms tab Don t forget you may also have to change the data entry control type to TextAreaWidget for fields that allow for multi line text entry 25 9 May 2005 k INSTANCE EDITOR Herbal Name MoveBlockToBlock Herbal Definition For Instance MoveBlockToBlock instance of herbal Operator internal name i v EJ x Herbal Preference Indifferent Y Moves a clear block on top of another clear block Herbal Conditions Herbal Actions Lele TwoClearBlocks MoveBlock1 OntoBlock2 Figure 21 The completed MoveBlockToBlock operator M INSTANCE EDITOR For Instance TwoClearBlocks instance of herbal Condition internal name is b Xx x iX Herbal Name TwoClearBlocks Herbal Definition If there are two clear blocks and the first block is not on top ofthe second block Herbal StateMatches herbal Workin
35. le action complete the first Herbal operator The completed MoveBlockToTable operator is shown in Figure 20 Prot g Tip Once again when filling in the attributes you may need to arrange the forms in Prot g using the Prot g Forms tab Don t forget you may also have to change the data entry control type to TextAreaWidget for fields that allow for multi line text entry 22 9 May 2005 INSTANCE EDITOR MoveBlockToTable instance of herbal Operator internal name i x X MoveBlockToTable Indifferent a IM oves a clear block onto a clear table E ClearBlockClearTable MoveBlockOntoTable Figure 20 Completed MoveBlockToTable operator From this dialog box it is easy to tell what this operator does it is proposed when there is a clear block and a clear table and if applied it moves the block onto the table In addition this operator can be reused in other models or in a single model across multiple states Finally individual conditions and actions can also be easily reused by many operators or elaborations within a model or in other models 8 Once the MoveBlockToTable operator is complete it should be assigned to the Herbal Operators attribute of the top state Don t forget this step or else the operator proposal and operator application rules will not be generated 4 9 Creating the MoveBlockToBlock Operator and Assigning it to the Top State 1 The steps for creating the MoveBloc
36. lock1 gt blocks Clear true blocks Type Block lt Block2 gt blocks Clear true blocks Type Block lt OnTop gt blocks Bottom lt gt lt Block2 gt blocks Top lt Block1 gt blocks Bottom lt CurrentBottomBlock gt gt lt s gt operator o lt o gt name MoveBlockToBlock Block1 Blockl Block2 lt Block2 gt CurrentBottomBlock lt CurrentBottomBlock gt OnTop lt OnTop gt sp apply MoveBlockToBlock state lt s gt herbal Name BlocksWorldState operator lt o gt lt o gt name MoveBlockToBlock Block2 lt Block2 gt CurrentBottomBlock lt CurrentBottomBlock gt OnTop lt OnTop gt gt lt Block2 gt blocks Clear true lt Block2 gt blocks Clear false lt OnTop gt blocks Bottom lt CurrentBottomBlock gt lt OnTop gt blocks Bottom lt Block2 gt lt CurrentBottomBlock gt blocks Clear false lt CurrentBottomBlock gt blocks Clear true Listing 4 Operator proposal and operator application productions for the MoveBlockToBlock Operator 4 10 Creating the GoalStateReached Elaboration and Assigning it to the Top State The final step in the model creation is to create an elaboration and assign it to the top state This elaboration s responsibility will be to watch for the goal state and when reached terminate the model Creating an elaboration is very similar to the creating an operator
37. m This will present you with the Included Project dialog box 2 From the Included Project dialog box select herbal X pprj and click on Open A dialog box that reads Changing the included projects will cause the current project to be saved and reloaded will appear click on OK to complete the include process 3 When the process completes you will be presented with the Namespaces dialog box Namespaces are commonly used in XML to help uniquely define elements that make up an XML document Because RDF is XML based Prot g uses namespaces to distinguish between all of the RDF projects currently used by your Prot g project Notice that the dialog shown in Figure 6 lists four namespaces the default namespace for your BlocksTutorial model the herbal namespace for the Soar ontology and the remaining two namespaces for RDF Verify that your namespaces dialog looks like Figure 6 Namespaces he following namespace abbreviations are used abbreviation URI psu edu blocks rd syntacnst raiTR 18898 PR rdf schema 198989803033 don t show this window again m Close Figure 6 Namespaces dialog 4 Dismiss the Namespaces dialog by clicking on the Close button This completes the import process of the Herbal ontology and you are now ready to start creating your Soar model For Advanced Herbal Users The same process can be used to include any RDF based P
38. made to the Herbal environment that will break older models At some point in time as Herbal development stabilizes an attempt will be made to maintain backward compatibility across future releases 37 9 May 2005 References Cohen A M Ritter F E amp Haynes S R 2005 Herbal A high level language and development environment for developing cognitive models in soar Paper presented at the 14th Behavior Representation in Modeling and Simulation BRIMS University City CA Council I G Haynes S R amp Ritter F E 2003 Explaining Soar Analysis of Existing Tools and User Information Requirements Paper presented at the Proceeding of the International Conference on Cognitive Modeling Bamberg Germany Council I G Morgan G P amp Ritter F E 2004 dTank A Competitive Environment for Distributed Agents No ACS 2004 1 Pennsylvania State Unviersity Haynes S R Ritter F E Council I G amp Cohen M A submitted Explaining Intelligent Agents Manuscript submitted for publication Laird J E Congdon C B amp Coulter K J 1999 The Soar User s Manual Version 8 2 University of Michigan Morgan G P Cohen A M Haynes S R amp Ritter F E 2005 Increasing Efficiency of the Development of User Models JEEE System Information and Engineering Design Symposium Morgan G P Ritter F E Cohen M A Stevenson W E amp Schenck I N 2005 dTank An Environment
39. n that proposes operator move right Operator Definition If the tank is to my right and I am facing right move right Proposal Conditions Basic condition set true if I am facing right true if a tank is to my right Listing 6 Herbal s automatically generated documentation 7 3 How to Execute the Generated Herbal dTank Model Executing the dTank productions generated by the Herbal dTank model is quite simple 1 Run dTank as described in the dTank User s Guide Isaac G Council et al 2004 2 Run Soar as describe in the Soar User s Manual Laird et al 1999 3 Load the Tcl Tk script soar dTank interface 2 0 7 tcl located in the htank directory of the Herbal IDE installation folder the command to load this script can also be included on the compiler tab as included code and therefore automatically inserted into the generated code for you 4 Load the dTank Soar model generated by Herbal 5 Run the model 7 4 Suggestions for Expanding the Model Once you have studied the Herbal dTank model and have executed it you may want to expand the model in order to create a more intelligent tank The following is just a short list of possible improvements Hopefully this list will stir your imagination 1 Create a new action that turns on the tank s shields and create new conditions that test to see if your tank is nearing death or under fire Next create an operator that utilizes your new action and conditions
40. n was correctly installed by the Prot g installation program run Prot g by double clicking on its icon and then look for RDF Files listed as a project format option in the Prot g open project dialog which comes up as Prot g starts as shown in Figure 1 If you do not see RDF Files listed as a project format it is likely that you did not download the full version of Prot g Protege Project Format Open Recent Help Default Files pont and pins E nS Getting Started ntan Default Database herbal 0 9b FAQ RDF Fil blocksWorld 0 9 User s Guid herbal 0 9 odi Rer seibel All Topics blocksWorld 1 0 hungryThirsty T New Build Open Other Qpr ot g Figure 1 Testing the RDF plug in installation If RDF Files appears in this startup screen middle left RDF support has been successfully installed 2 9 May 2005 2 3 Install Herbal The latest Herbal distribution file can be downloaded from acs ist psu edu projects herbal Installing the Herbal IDE requires a unzipping the Herbal distribution folder and b placing the herbalWidgets jar file into the Prot g plugins folder a To install Herbal create a folder on your local hard drive called herbal X where X is the version number Unzip the herbal X distribution into this folder When the decompression process is complete browse to the herbal X folder and be sure that the files listed in Table 1 are located in this folder
41. nce of herbal Elaboration i X X Herbal Name GoalStateReached Herbal Definition Terminates the model if black Ais on block B block B is on block C and block C is on the table Herbal Conditions LA Herbal Actions ha IsGoalReached Done Figure 26 The completed GoalStateReached Elaboration 28 9 May 2005 sp elaborate GoalStateReached state lt s gt herbal Name BlocksWorldState herbal WorkingMemory lt AOnB gt herbal WorkingMemory lt BOnC gt herbal WorkingMemory lt BlockA gt herbal WorkingMemory lt BlockB gt herbal WorkingMemory lt BlockC gt herbal WorkingMemory lt COnTable gt herbal WorkingMemory lt Table gt lt Table gt blocks Clear true blocks Type Table lt BlockA gt blocks Clear true blocks Type Block herbal Name A lt BlockB gt blocks Clear false blocks Type Block herbal Name B lt Blockc gt blocks Clear false blocks Type Block herbal Name C lt COnTable gt blocks Top lt BlockC gt blocks Bottom lt Table gt BOnC blocks Top lt BlockB gt blocks Bottom lt BlockC gt lt AOnB gt blocks Top lt BlockA gt blocks Bottom lt BlockB gt write Goal Reached halt Listing 5 The generated Soar code for the GoalStateReached elaboration 5 0 Compiling the Blocks World Model Once the model has been specified in Prot g it is possible t
42. ngle line of text in these fields If you have further questions about how to customize data entry forms in Prot g please see the Prot g documentation Once the domain specific classes have been created you are ready to instantiate knowledge For the Blocks World problem the knowledge consists of three blocks all of which have nothing on top of them In addition there is one table and three OnTop relationships Each relationship specifies that a block is on the table In other words the environment begins with three blocks sitting on a table To instantiate this knowledge 1 9 May 2005 1 Make sure the Instances tab is selected and expand the herbal HerbalClass node in the instances tree 2 Creating instances of a class is a typical Prot g task and was described in the Prot g tutorial At this point you should be familiar with how to create instances using Prot g working from Instances tab select the class you want to instantiate and click on the create button Prot g Tip When creating instances of classes from the Prot g Instances tab be sure to set the display slot for the class you are going to be using The display slot specifies what attribute of your instance will be used as a label when Prot g needs to list your object If you see labels like blocksWorld Instance 30000 it means you forgot to set the display slot For the blocks world you want to create three blocks one tabl
43. o compile the model into Soar productions The automatic generation of Soar productions provided by the compiler helps in many ways including the reuse of Herbal objects such as operators actions and conditions This reuse makes it possible to create the object once and use it multiple times If you find an error and need to change the Herbal object you only have to change it in one place and the compiler takes care of the rest To run the compiler from the Model Attributes tab follow these steps 1 Configure Prot g to use the Herbal Compiler tab From the Prot g Project menu select the Configure menu item This will display the Configure dialog box In this dialog box select the Tab Widgets tab and then check the CompilerTab check box If you do not see CompilerTab listed here please close down Prot g make sure the herbalWidgets jar file is located in the Prot g plugins folder and then restart Prot g This step only needs to be performed once per Herbal model 29 9 May 2005 2 Save the current version of your Blocks World Prot g project Do not forget this step or your most recent changes will not be included in the compiled code 3 Click on the Herbal Compiler tab located in the main Prot g window see Figure 27 4 Click on the Generate Soar Code button to launch the compiler see Figure 27 When the compiler is done a file named model soar containing Soar prod
44. oject in the BlocksTutorial folder you created in Step 1 To do this select Save As from the Project menu and then click on the button next to the Project field in the RDF Files dialog box as shown in Figure 4 RDF Files Project l Figure 4 The Browse button in the Save As RDF Files Dialog Clicking on this button will display a file Save As dialog box Browse to the BlocksTutorial folder you created in Step 1 type the name of your new project BlocksTutorial in the file name edit box and then click on the select button Take the defaults provided by Prot g for the Classes file name and the Instances file name and enter http protege stanford edu kb blocks for the Namespace field When you are done the dialog should looks something like Figure 5 5 9 May 2005 RDF Files BlocksTutorial BlocksTutorial rdfs BlocksTutorial rdf http protege stanford eduskb blocks plain RDFS may loose Protege specific facets J OK X Cancel Figure 5 RDF Files Save As dialog Prot g Tip There is a bug in Prot g that causes the Save As dialog box to behave differently than may be expected If you find that you cannot dismiss the Save As dialog box you may have forgotten to enter the name that you want to give to your new project file in the file name edit box Repeat step 4 and pay close attention to the text in bold 5 Click OK
45. problem much quicker To accomplish this we need to generate an impasse that will create a child state By adding operators to this new child state we can determine what operator is best and create a preference for that operator in the top state thereby resolving the impasse By changing the preference for the MoveBlockToBlock operator from indifferent to acceptable the model will no longer know how to choose the correct MoveBlockToBlock operator and an Operator Tie impasse will occur This impasse will result in the creation of a new state and from within this new state new operators can help resolve the tie and choose the best MoveBlockToBlock operator 6 1 Generating an Operator Tie Impasse The first step to utilizing hierarchical states for problem solving is to allow an impasse to occur This can be done using the current blocks world model by changing the Herbal Preference for the MoveBlockToBlock operator from indifferent to acceptable In doing so the model will encounter an operator tie impasse whenever there is more than one MoveBlockToBlock operator to choose from Try changing the preference setting for the MoveBlockToBlock operator recompiling the model and running it in Soar You should notice that the model immediately encounters an operator tie impasse 6 2 Creating an Herbal Child State It is possible to create a child state in Herbal that will represent the state that is be generated by the impasse we just introduce
46. r Figure 10 Block attributes 10 ng Type 9 May 2005 Table Name Cardinality Type um Clear single String Height single Integer herbal Definition required single String herbal How itworks single String herbal Name required single String herbal Purpose single String m Type single String Figure 11 Table attributes OnTop Name Cardinality Type m Bottom single Instance of Block or Table herbal Definition required single String herbal How itworks single String herbal Name required single String herbal Purpose single String m Top single Instance of Black Figure 12 OnTop relationship attributes 4 5 Instantiating Domain Specific Knowledge Prot g Tip Due to a bug in Prot g some of the data entry forms that you will be using to enter knowledge will not be laid out cleanly Fortunately Prot g allows you to customize these data entry forms To accomplish this click on the Forms tab in Prot g and arrange the forms for the Block Table and OnTop classes You can arrange these forms in Prot g easily by just dragging the data entry controls to a location on the screen that will make for easy data entry Be creative and try and create forms that will be easy to use You may also have to change the data entry control type to TextAreaWidget for fields that allow for multi line text entry i e the Definition field If you forget to do this you will only be allowed to enter a si
47. rentBottomBlock blocks Clear false K CurrentBottomBlock blocks Clear true Herbal Purpose Figure 19 MoveBlockOntoTable action To better understand how an action object works the attributes in this dialog box should be explained in more detail Once again the herbal Name and herbal Definition are self explanatory so we should start the herbal OperatorMemory attribute The herbal OperatorMemory object makes it possible for the modeler to specify what objects it will be using to perform its action These objects must exist in the union of all of the herbal OperatorMemory attributes of the conditions associated with this operator In other words you cannot manipulate an object in an action unless it has been matched and remembered by one of the conditions used by this operator In this case the new action must have access to the current bottom block the currently matched table and the OnTop relationship for the block that is going to be moved to the table Because the ClearBlockClearTable condition that we just created has 21 9 May 2005 included these objects in its Herbal OperatorMemory attribute they will be available when this action is applied This is the mechanism for pairing conditions and actions The most important attribute of an Herbal Action object is the Herbal Exp This is where the action is specified In this case the objective is to move the matche
48. rot g installation you can choose between an installation that contains a current JVM and an installation that assumes you already have the correct JVVM installed If you do not already have a version 1 4 2 or higher compliant JVM installed on your machine be sure to select the Prot g installation that contains the proper JVM If you have an earlier version of the JVM you should uninstall it before continuing with the Prot g install From the Prot g download page you should choose to download the full Prot g 3 0 installation Prot g 3 0 is available for several different platforms including Windows Mac OSX and Linux Finally remember to select the package that contains the Java virtual machine if you do not currently have a version 1 4 2 compliant JVM installed After the download completes double click the downloaded file and follow the installation instructions on the screen as they appear during the installation 2 2 Install the RDF Prot g Plug in Herbal uses the Resource Description Framework RDF as its main representation language and Herbal relies on Prot g to generate RDF when a project is saved W3C 2004 Asa result the Prot g backend plug in that generates RDF must be installed before you can start using Herbal Because this plug in is part of the full Prot g distribution it is installed by default when the full version of Prot g is installed To test Prot g and to test that the RDF plug i
49. rot g project In other words you can reuse pieces of other Soar models created in Herbal i e working memory elements states operators elaborations actions and conditions by just including them into your next project in this fashion 7 9 May 2005 4 3 Setting the Model Attributes The first step towards defining the model is to specify the top level model attributes These attributes are important because they provide documentation that can help explain the purpose of the model and how the model works Setting these attributes can be accomplished using the Model Attributes tab This tab is unique to Herbal and will only be displayed if the herbalWidgets jar file was copied to the Prot g plugins folder as described in the section entitled Installing the Herbal Files and if Prot g was configured to use the plug in as described below To configure Prot g to use the Model Attributes tab from the Project menu select the Configure menu item This will display the Configure dialog box In this dialog box select the Tab Widgets tab and then check the ModelAttributesTab check box If you do not see the ModelAttributesTab listed here please close down Prot g make sure the herbalWidgets jar file is located in the Prot g plugins folder and then restart Prot g After checking the ModelAttributesTab check box click on the OK button and you should
50. s a field named Included Code as shown in Figure 27 Any text entered into this field will be automatically inserted at the top of the code generated by Herbal Text can be inserted into the Included Code field by either 30 9 May 2005 manually typing the text in or by inserting the contents of a file using the Browse button If enter or insert any code in the Included Code field be sure to save your model before running the compiler 6 0 Impasses and Child States Up to this point the blocks world model you have built contains a single top level state named BlocksWorldState However it is often useful to use a hierarchy of states in order to add structure to a problem solving algorithm This is best illustrated with an example In the current implementation of the blocks world model it is possible for more than one MoveBlockToBlock operator to be valid For example in the initial state of the blocks world there are six different MoveBlockToBlock operators move block A onto block B move block A onto block C move block B onto block A move block B onto block C move block C onto block A and move block C onto block B Because the MoveBlockToBlock operator is marked as indifferent the architecture will select one of the six operators for you However it may be desirable to include some problem solving logic that prefers one of the moves For example if we could prefer moving B onto C and then A onto B we could solve the
51. st click on the plus sign next to the Herbal WorkingMemory attribute and select the working memory instances that have already been created This is a commonly forgotten task so be sure to add your working memory to the state 2 When you are done the working memory attribute for the top state should resemble Figure 16 Figure 16 Top state working memory As shown in Listing 1 adding these working memory elements to the top state will create an elaboration in the generated Soar code that attaches the appropriate attributes to the top state 16 9 May 2005 sp elaborate initial state BlocksWorldState state lt BlocksWorldState gt type state superstate nil gt lt BlocksWorldState gt herbal Definition The Blocks World Problem Space herbal Name BlocksWorldState herbal WorkingMemory lt Table gt herbal WorkingMemory lt AOnTopOf gt herbal WorkingMemory lt BOnTopOf gt herbal WorkingMemory lt COnTopOf gt herbal Elaborations lt GoalStateReached gt herbal WorkingMemory lt A gt herbal WorkingMemory lt B gt herbal WorkingMemory lt C gt lt Table gt blocks Clear true blocks Height 22 blocks Type Table herbal Definition A table herbal Name Table lt AOnTopOf gt herbal Definition A relationship that specifies block A is on top of herbal Name AOnTopOf blocks Bottom lt Table gt blocks Top lt A gt lt A gt
52. tBottomBlock lt CurrentBottomBlock gt OnTop lt OnTop gt Table lt Table gt Listing 2 Operator proposal generated based on the ClearBlockClearTable condition An operator gets its functionality from its conditions and actions In the last step a condition was assigned to the MoveBlockToTable operator and this condition resulted in the creation of an operator proposal in the generated Soar code In the next few steps we will create and assign an action and this action will result in the creation of an operator application in Soar To create the action click on the create next to the Herbal Actions attribute of the MoveBlockToTable operator This will display the new action dialog box 20 9 May 2005 6 When the new action dialog box is displayed you should assign the new action the attributes shown in Figure 19 Prot g Tip Once again when filling in the attributes you may need to arrange the forms in Prot g using the Prot g Forms tab Don t forget you may also have to change the data entry control type to TextAreaWidget for fields that allow for multi line text entry MoyeBlockOntoTable instance of herbal Action internal name is Herbal Nam MoveBlockOntoTable Herbal Definition Moves Block from a block onto the Table Herbal OperatorMemory Table lt OnTop CurrentBottomBlock blocks Bottom lt CurrentBottomBlock s Bottom lt Table K Cur
53. to look for an enemy Fire If there is an enemy tank spotted on the same x coordinate as my tank fire In addition to the reuse of operators across different models these operators also demonstrate code reuse within the same model For example nearly all of the operators listed in Table 9 share the same basic condition This condition matches the input and output link and the current tank s status and visual field Because this condition is reused by most of the operators in the model a simple change to the basic condition is immediately reflected in most of the operators in the model Code regeneration imposes this change across several productions automatically eliminating the need for copy and pasting and the possibility for typos Table 10 lists all of the conditions used by the dTank model along with the operators that use these conditions 34 9 May 2005 Table 10 A Summary of the conditions used in the Herbal dTank Model and how these conditions are shared by operators Condition Used By Basic condition commandIsComplete facing left facing right no tank seen not facing left not facing right nothingGoingOn tank left tank online tank right turret down turret up aim up aim down fire move left move right turn left turn right Wait move left move right aim up aim down turn left turn right wait move left turn left Fire move right turn right aim up aim down The
54. uctions will be created in the BlocksTutorial folder and also displayed in a window After checking the code visually you can close the window and then load the model into Soar for testing File Edit Project Window Help ajme amp lO A EE i ax lt G prot g Classes Slots Forms Instances Queries Model Attributes ver 0 9b Herbal Compiler ver 0 9b Included Code Browse t using a because it works with both 8 5 and 8 6 Compiler Definition File herbal 0 9b xslt Browse Output File saved with model file by default orld mo Generate Soar Code blocks world model soar Figure 27 The Herbal Compiler Tab Operators Missing Are some of your operators or elaborations missing from your generated code A common mistake is to forget to assign your operators and elaborations to the top state This results in the operators never getting generated in the Soar code If you can t find your operators in your code go back and make sure they have been added to your top state Recent Changes Missing Are your most recent changes missing from the generated code A common mistake is to forget to save you model before clicking on the Generate Soar Code button Try saving the model and regenerating the code 5 1 Including Custom Code in Your Model It is possible to have Herbal include custom Soar rules or Tcl Tk scripts automatically in the generated model The Herbal Compiler tab contain

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