### Factors Inducing Cybersickness
#### 1.1.2 Operational Factors  
Operational factors include hardware, operating methods, and exposure time. According to relevant studies, these are important factors affecting the occurrence of cybersickness ([PERSON] et al., 2021; [PERSON] et al., 2021; [PERSON] et al., 2021). (1) Hardware  
Users usually need to operate in VR through hardware interfaces. Such interfaces can be divided into displays and controllers. 1. Displays  
There are three main characteristics of displays inducing cybersickness ([PERSON] et al., 2021; [PERSON] et al., 2021; [PERSON] et al., 2021):  
* Types, such as a head-mounted device (HMD), flat-panel display, projection display, or reality [PERSON]. * Characteristics, such as field of view (FOV) and [PERSON] of field. * Quality, such as resolution, tracking gap, flicker, and latency. Cybersickness caused by displays mainly results from sensory conflicts, which lead to nausea and other symptoms. Disorientation caused by body movement, head movement, and incorrect optical design can also cause eye discomfort. Research has shown that head-mounted displays are more likely to cause cybersickness than flat displays are ([PERSON] et al., 2021). [PERSON] and [PERSON] (2019) reported that head-mounted displays induce cybersickness mainly because of factors such as field of view, contrast, lighting, duration, and working distance, which cause strain on vision ([PERSON] et al., 2021). Research has also revealed that approximately 60% of users reported symptoms such as visual fatigue, nausea, and headaches when using head-mounted displays in immersive virtual environments ([PERSON] et al., 2021). In addition, considering other types of displays, [PERSON] et al. (2004) concluded that large displays can improve the sense of presence, but they do not directly affect or induce cybersickness ([PERSON] et al., 2021). In terms of display characteristics, the size and depth of the field of view affect the degree of cybersickness, and limitation of the dynamic visual field can reduce the severity of cybersickness ([PERSON] et al., 2021). In terms of quality, some researchers have reported that factors such as the tracking gap, flicker, and latency can induce cybersickness [21]. However, with the advancement of technology, the quality of displays has significantly improved. 2. Controllers  
In the virtual world, active control is the main navigation method. Generally, the controllers used in VR include a mouse, wireless hand controller, and gesture capture controller. A good virtual environment controller can greatly reduce the occurrence of cybersickness if it allows users to have a high degree of correlation with expected reactions while performing operations [19]. With respect to the controllability of VR, [PERSON] et al. (2011) reported that passive control is more likely to cause cybersickness than active control [25]. 2. Operating status  
Researchers have reported that cybersickness is strongly affected by the speed of scene rotation [26, 27]. [PERSON] et al. (1999) conducted a study in which a rotating drum with black and white stripes was used [28]. In this study, the circular vector speed of the rotating drum was set from 15\({}^{\circ}\)/s to 90\({}^{\circ}\)/s. The results showed that as the angular velocity of rotation increases, induced motion sickness, including cybersickness, gradually increases. The peak value mainly appears at an angular rotation velocity of 60\({}^{\circ}\)/s and gradually decreases. This result shows that increasing the angular rotation velocity gradually increases the severity of cybersickness symptoms, but after reaching a peak value, the severity gradually stabilizes. Recently, [PERSON] and [PERSON] (2020) reported that when the angular rotation speed is less than 15\({}^{\circ}\)/s, the symptoms of cybersickness in subjects are not obvious [16]. When the angular rotation speed exceeds 65\({}^{\circ}\)/s, the symptoms of cybersickness become obvious and severe. With respect to the speed of scene motion, [PERSON] et al.