Alternative Text Description for Fig. 2:

Figure 2 is a line graph, showing the changes of the times required for six trainees to finish the picking work test. The x-axis and y-axis represent the number of the trials and the time required for each trainee to finish the test, respectively. The trainees 1 to 3 took the test without PDA but with memos, and the trainees 4 to 6 did by using the PDA. The times required for trainee 5 and 6 decreased gradually as the trial number increased. On the other hand, the rest trainees could not reduce the times smoothly.