## 2 Methodology
### Shelf Arrangement and OP Tasks  
The laboratory setup for the OP tasks included the installation of eight shelves measuring 1.85 \(\times\) 1.22 \(\times\) 0.5 m, with five levels on each shelf (see Figure 2). The eight shelves comprised a total of eight stocking areas: AA, AB, AC, AD, BA, BB, BC, and BD. The first four constituted zone A and the other four constituted zone B. The AA and BA areas were positioned near the origin, approximately 2 m from the edge of the shelves. The distance between the AC-AD and BA-BB shelves was approximately 1 m. A total of 199 boxes, varying in size, were allocated to these storage areas. In the AA and AC areas, 15 large boxes measuring 25 cm \(\times\) 25 cm \(\times\) 25 cm were stored. The AB and AD areas housed 36 small boxes measuring 12.5 cm \(\times\) 23 cm \(\times\) 15.5 cm, while the BA and BC areas contained 25 medium-sized boxes measuring 15 cm \(\times\) 26 cm \(\times\) 18 cm. The BB and BD areas accommodated boxes of all three dimensions. The boxes to be picked by each participant were randomly arranged on the eight shelves.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Dimension** & **Questions** \\ \hline \hline \multirow{4}{*}{Emotion} & I am worried about how I look when I wear this device. \\  & I am tense when I wear the device. \\  & I feel uncomfortable when I wear the device. \\  & I feel a headache when I wear the device. \\  & I feel the device was heavy. \\ Attachment & I feel difficult to wear the device. \\  & I can feel the device moving. \\  & I feel my physical look different. \\ Perceived change & I am awkward when I wear this device. \\  & I feel strange wearing the device. \\ Movement & The device affects the way I move. \\  & The device restricts my movement. \\ Anxiety & I do not feel secure wearing the device. \\ \hline \hline \end{tabular} Source: [PERSON] et al. [38].  
\end{table}
Table 1: Dimensions and questions of the comfort rating scales.  
QR codes were designed for each box on the shelves. The QR code and text-based code number were attached to the bottom of each box (see Figure 3). When the participant scanned the code, the code information of the current box and the code and location information of the next box to be picked appeared. For example, when the participant scanned the QR code in Figure 3, the code and location information of the next item to be picked (pick => A-AA-041; row: 4; column: 1) appeared in addition to the current code number (A-AA-023). An error message occurred if the participant scanned the incorrect current box. For the order map and 3D graph picking, an activation QR code was attached to the side of shelf AA near the origin. Participants could scan this code to activate the order map (see Figure 4) and the 3D graph (see Figure 5) and access the box location information for picking. Arrows were provided only for the order map picking to show the sequence of the item-picking tasks. Participants were instructed to accomplish the picking task following the task instructions on the AR device. All the QR codes, order maps, and 3D graphs were designed and pre-arranged by the second author ([PERSON]).  
Figure 3: A QR code attached on a box.  
Figure 2: The layout of the experiment: (**a**) top view; (**b**) view from the origin.