
| FHJ Agent:          | 591   |    |    |    |    |    |       |
|---------------------|-------|----|----|----|----|----|-------|
| Deletions:          | 44    | 36 | 9  | 10 | 4  | 8  | (111) |
| Additions:          | 0     | 32 | 5  | 21 | 0  | 1  | 59    |
| DHJ Agent:          | 539   |    |    |    |    |    |       |
| Additional Changes: | 0     | 33 | 8  | 0  | 24 | 0  | 65    |

![0_image_0.png](0_image_0.png)

to an entailed structure rather than one created as an assumption, but that structure is located in the same subtask. This somewhat restrictive definition of a change inflates the addition and deletion accounting. In many cases a production was "deleted" and then immediately "added" to a different subtask. For example, the productions that manipulate motor commands were all moved from local subtasks to the highest subtask. Almost all the additions and deletions in the "Remembering" category can be attributed to this move, which required no synthesis of new production knowledge.

Total knowledge required for the DHJ agents decreased. This approximately 9% reduction was achieved by making some type of modification to about **40% of the FHJ agent**
rules, and may seem a modest gain, given the conversion cost. **However, this cost is an** artifact of the chosen methodology. Had the DHJ agents been constructed in this domain without previously existing FHJ agents, at least a 9% decrease in the total knowledge would be expected. This result thus suggests a reduction in the cost of the agent design. The high conversion cost does suggest that converting a much larger system, like TacAir-Soar, would probably be very costly. On the other hand, the modifications were made evident by identifiable regenerations in the architecture. Thus, the 235 total changes made to the FHJ knowledge base were much easier to make than constructing a similar number of rules.

## 4.4.4 Performance Differences

As the performance results in Table 2 show, DHJ agents improved in performance relative to their FHJ peers. However, the improvements of the lead and wing agents was substantially different. Differences in the tasks of lead and wing pilots led **to the differences in relative** improvements.

Lead and Wing Agents**: The lead and wing agent share the same knowledge base but**
perform different tasks in the µTAS scenario.8 **These differences lead to differences in their**