Artificial intelligence software for grading of student problem-solving work

• US 20090286218A1
• Filed: 05/08/2009
• Published: 11/19/2009
• Est. Priority Date: 05/13/2008
• Status: Active Grant

• Current Assignee: Benny G. Johnson, Dale A. Holder
• Original Assignee: Benny G. Johnson, Dale A. Holder
• Inventors: Holder, Dale A., Johnson, Benny G.
• Granted Patent: US 8,472,860 B2
• Time in Patent Office: Days
• US Class Current: 434/353
• CPC Class Codes: G09B 7/02 of the type wherein the student is expected to construct an answer to the question which is presented or wherein the machine gives an answer to the question presented by a student

Abstract

Described is a method using a computer for grading student work on a problem when the student'"'"'s own steps are shown in detail. A reference trace is created representing a best solution path to the problem. A student trace of the student'"'"'s own work is then created, which involves searching explicitly for a specific rationale for appending a step to the student trace; deeming the step a correct production provided the step was able to be reproduced and marking the step as traced; provisionally accepting the step as part of the best solution path subject to revocation if a better-quality step is later found by a step conflict check; implicitly tracing the student'"'"'s work to discover implicitly taken mental steps provided the explicit tracing has failed to justify the step; appending any remaining untraced steps to the student trace and excluding them from the best solution path; computing a value of the steps in the student'"'"'s work to form a student value; and, comparing the student value to a total value of the steps in the reference trace to obtain a score.

Claims

1. A method using a computer for grading student work on a problem when the student'"'"'s own steps are shown in detail, said method comprising the following steps executed by said computer:

creating a reference trace representing a best solution path to said problem;

creating a student trace of the student'"'"'s work, further comprising the steps of;

explicitly tracing the student'"'"'s work by searching for a specific rationale for appending a step to said student trace;

provisionally accepting said step as part of said best solution path, subject to revocation if a better-quality step is later found by a step conflict check;

implicitly tracing the student'"'"'s work to discover implicitly taken unwritten mental steps provided the explicit tracing has failed to justify said step;

appending any remaining untraced steps to said student trace and excluding them from said best solution path;

computing a value of said steps in the student'"'"'s work to form a student value; and

,

comparing said student value to a total value of said steps in said reference trace, as a result producing and displaying at least a partial score for said student for said problem.

2. The method of claim 1, wherein the step of explicit tracing further comprises the steps of:

marking said step as traced and excluding said step for said best solution path if said step was not interpreted;

marking said step as traced and correct and including said step in said best solution path if said step was interpreted and reproducible; and

,

marking said step as traced and not correct and including said step in said best solution path if said step is interpreted and not reproducible but is still applicable.

3. The method of claim 2, further comprising the step of marking said step as traced and either incorrect or not correct but still part of said best solution path if said step conflicts with a previous step and the resulting conflict can be resolved by said step conflict check.

4. The method of claim 3, wherein the step of provisionally accepting further comprises the steps of:

marking said step as traced and excluding said step from said best solution path if said step is identical to a previously traced step;

marking said step as traced and excluding said step from said best solution path if said step is not correct when exchanged with a previously traced step in said best solution path; and

replacing a previous step with said step and marking said previous step and all traced steps as untraced and mark said step as correct if said previous step is not correct and said step is correct when exchanged with said previous step in said best solution path.

5. The method of claim 4, further comprising the step of creating a copy of said trace and on said copy, replacing said previous step with said step in said best solution path and marking only said step as correct and adding said copy to a queue of trace candidates to be later completed.

6. The method of claim 1, wherein the step of implicit tracing further comprises the steps of:

checking whether inserting a conflict step taken from a conflict set generated from said step conflict check would render said conflict step a correct production;

deeming said conflict step as said unwritten mental step which is correct provided said conflict step is a correct production; and

,

appending said unwritten mental step to said student trace.

7. A computer-readable medium for grading student work on a problem when the student'"'"'s own steps are shown in detail, said medium causing a computer to execute the following steps:

creating a reference trace representing a best solution path to said problem;

creating a student trace of the student'"'"'s work, further comprising the steps of;

explicitly tracing the student'"'"'s work by searching for a specific rationale for appending a step to said student trace;

provisionally accepting said step as part of said best solution path, subject to revocation if a better-quality step is later found by a step conflict check;

implicitly tracing the student'"'"'s work to discover implicitly taken unwritten mental steps provided the explicit tracing has failed to justify said step;

appending any remaining untraced steps to said student trace and excluding them from said best solution path;

computing a value of said steps in the student'"'"'s work to form a student value; and

,

comparing said student value to a total value of said steps in said reference trace, as a result producing and displaying at least a partial score for said student for said problem.

8. The medium of claim 7, wherein the step of explicit tracing further comprises the steps of:

marking said step as traced and excluding said step from said best solution path if said step was not interpreted;

marking said step as traced and correct and including said step in said best solution path if said step was interpreted and reproducible; and

,

marking said step as traced and not correct and including said step in said best solution path if said step is interpreted and not reproducible but is still applicable.

9. The medium of claim 8, further comprising the step of marking said step as traced and either incorrect or not correct but still part of said best solution path if said step conflicts with a previous step and the resulting conflict can be resolved by said step conflict check.

10. The medium of claim 9, wherein the step of provisionally accepting further comprises the steps of:

marking said step as traced and excluding said step from said best solution path if said step is identical to a previously traced step;

marking said step as traced and excluding said step from said best solution path if said step is not correct when exchanged with a previously traced step in said best solution path; and

replacing a previous step with said step and marking said previous step and all traced steps as untraced and mark said step as correct if said previous step is not correct and said step is correct when exchanged with said previous step in said best solution path.

11. The medium of claim 10, further comprising the step of creating a copy of said trace and on said copy, replacing said previous step with said step in said best solution path and marking only said step as correct and adding said copy to a queue of trace candidates to be later completed.

12. The medium of claim 7, wherein the step of implicit tracing further comprises the steps of:

checking whether inserting a conflict step taken from a conflict set generated from said step conflict check would render said conflict step a correct production;

deeming said conflict step as said unwritten mental step which is correct provided said conflict step is a correct production; and

,

appending said unwritten mental step to said student trace.