First question information includes questions about a predetermined subject, and each piece of first answer information, associated with a piece of the first question information, indicates an answer that is responsive to the question indicated by the piece of the first question information. The apparatus updates conversion parameters including correlation values each indicating a degree of a correlation between keywords included in the first question information and the first answer information, by adjusting the correlation values so that the keywords enable a predetermined degree of predicted reliability to search for the first answer information. Upon receiving a new question not included in the first question information, the apparatus determines, based on the updated conversion parameters and first keywords extracted from the new question, second keywords enabling the predetermined degree of predicted reliability, and searches for an answer that is responsive to the new question by using the second keywords.
Please help me write a proper abstract based on the patent claims. CLAIM: 1. A non-transitory, computer-readable recording medium having stored therein a program for causing a computer to execute a process comprising: providing answer information including information on answers to questions about a predetermined subject; providing first question information and first answer information, the first answer information being included in the answer information, each piece of the first question information indicating a question about the predetermined subject, each piece of the first answer information being associated with a piece of the first question information and indicating an answer that is responsive to the question indicated by the piece of the first question information; updating conversion parameters that include correlation values each indicating a degree of a correlation between keywords included in the first question information and the first answer information, by: calculating, for each keyword included in the first question information and the first answer information, a correlation score indicating a degree of predicted reliability of the each keyword to search for a corresponding piece of the answer information, based on the updated conversion parameters, and adjusting the correlation values so that the calculated correlation score indicates a predetermined range of values for keywords included in the first question information and the first answer information; and upon receiving a new question about the predetermined subject which is not included in the first question information, determining, based on the updated conversion parameters and first keywords extracted from the new question, second keywords as keywords whose correlation scores are within the predetermined range of values, and searching the answer information for an answer that is responsive to the new question by using the second keywords. 2. The non-transitory, computer-readable recording medium of claim 1, wherein the updating the conversion parameters is performed by executing machine learning on the correlation values, by using, as learning data, keywords extracted from the first question information and keywords extracted from the first answer information. 3. The non-transitory, computer-readable recording medium of claim 2, wherein the updating the conversion parameters is performed by executing machine learning on the correlation values, by using, as learning data, a part of keywords extracted from the first question information and a part of keywords extracted from the first answer information. 4. The non-transitory, computer-readable recording medium of claim 1, wherein the determining the second keywords includes: calculating, for each of keywords extracted from the first question information and the first answer information, the correlation score regarding the first keywords, and determining the second keywords, based on the calculated correlation scores. 5. The non-transitory, computer-readable recording medium of claim 4, wherein the predetermined range of values is a range of values that are equal to or greater than a predetermined threshold. 6. The non-transitory, computer-readable recording medium of claim 4, wherein the determining the second keywords is performed by: identifying third keywords that are included in the first keywords and are not included in keywords whose degree of predicted reliability is equal to or greater than the predetermined threshold, and determining the second keywords as keywords that are included in the first keywords and not included in the third keywords. 7. The non-transitory, computer-readable recording medium of claim 4, wherein the determining the second keywords is performed by: identifying third keywords that are not included in the first keywords and whose degree of predicted reliability is equal to or greater than the predetermined threshold, and determining the second keywords as keywords that are included in the first keywords or the third keywords. 8. The non-transitory, computer-readable recording medium of claim 1, wherein the searching the answer information is performed by using a part of the second keywords. 9. An apparatus comprising: a memory configured to store: answer information including information on answers to questions about a predetermined subject, and first question information and first answer information, the first answer information being included in the answer information, each piece of the first question information indicating a question about the predetermined subject, each piece of the first answer information being associated with a piece of the first question information and indicating an answer that is responsive to the question indicated by the piece of the first question information; and a processor coupled to the memory and configured to: update conversion parameters that include correlation values each indicating a degree of a correlation between keywords included in the first question information and the first answer information, by: calculating, for each keyword included in the first question information and the first answer information, a correlation score indicating a degree of predicted reliability of the each keyword to search for a corresponding piece of the answer information, based on the updated conversion parameters, and adjusting the correlation values so that the calculated correlation score indicates a predetermined range of values for keywords included in the first question information and the first answer information; and upon receiving a new question about the predetermined subject which is not included in the first question information, determine, based on the updated conversion parameters and first keywords extracted from the new question, second keywords as keywords whose correlation scores are within the predetermined range of values, and search the answer information for an answer that is responsive to the new question by using the second keywords. 10. A method comprising: providing answer information including information on answers to questions about a predetermined subject; providing first question information and first answer information, the first answer information being included in the answer information, each piece of the first question information indicating a question about the predetermined subject, each piece of the first answer information being associated with a piece of the first question information and indicating an answer that is responsive to the question indicated by the piece of the first question information; updating conversion parameters that include correlation values each indicating a degree of a correlation between keywords included in the first question information and the first answer information, by: calculating, for each keyword included in the first question information and the first answer information, a correlation score indicating a degree of predicted reliability of the each keyword to search for a corresponding piece of the answer information, based on the updated conversion parameters, and adjusting the correlation values so that the calculated correlation score indicates a predetermined range of values for keywords included in the first question information and the first answer information; and upon receiving a new question about the predetermined subject which is not included in the first question information, determining, based on the updated conversion parameters and first keywords extracted from the new question, second keywords as keywords whose correlation scores are within the predetermined range of values, and searching the answer information for an answer that is responsive to the new question by using the second keywords.