## 4 Results and Discussion
### Validation of the Behavior of the Motion Intention Switcher (MIS)  
In order to validate the behavior of MIS in switching the intention based on the pointing gestures, experiments have been carried out in 10 different layout scenarios where such intention switching may be required in order to effectively evaluate the user instructions. Each participant was given the chance to perform the evaluation in any two of the previously unused arrangements among these 10 scenarios. The behavior of the proposed method (i.e., the system with MIS) and the system without the intention-switching ability (i.e., the system presented in [20]) have been analyzed in those situations. The sample results obtained from the experiment are given in Table 2. The views from the robot with tracked skeletons of the users in the sample cases are shown in Figure 6 along with the third person view of the scenarios. The corresponding positions of the robot during the execution of each case are marked on the map shown in Figure 7.  
In case (a), the robot was initially placed on the location '\(a_{1}\)' without deploying the MIS to the system. Then, the robot was commanded, \"move far forward\". The uncertain term in the command is \"far\" and the robot had to quantify the meaning of \"far\" for fulfilling the user command by navigating to the desired location. In this case, \(D_{r}\) was 33 cm since the robot only considers the immediate obstruction in its intended straight moving path. Therefore, the perceptive distance \(D\) was 33 cm and the quantified output generated from the UIUM was 29 cm, resulting a destination position in between the robot and the obstacle as explained in Section 3.3.1. Therefore, the robot moved to location '\(a_{9}\)'. Then, the MIS was activated and the robot was again placed at the initial position (i.e., location '\(a_{1}\)'). The robot was again commanded with the same voice instruction accompanied with a pointing gesture that expresses that the intention of the instruction is to navigate the robot to a position that is beyond the obstacle. The gesture evaluation system interpreted the gesture and calculated \(D_{gesture}\) was 121 cm. In this situation, the perceptive distance was altered by MIS to alternative perceptive distance \(D_{a,max}\) since \(D_{gesture}>\delta_{max}D_{r}\). \(D_{a,max}\) was evaluated as 252 cm and it was assigned to the perceptive distance (\(D\)). Therefore, the output of the UIUM was 199 cm that resulted a destination position beyond the obstacle and then robot moved to location '\(a_{A}\)' by taking a curvy path generated by the navigation controller for avoiding the obstacle. In case (b), the robot was initially placed in location '\(b_{1}\)' with disabled MIS. Then it was commanded, \"move medium right\". The robot had to quantify the meaning of the uncertain term \"medium\" in order to move to the destination position requested by the user. Here, \(D_{r}\) was 272 cm. Subsequently, \(D\) and the quantified outputs were 272 cm and 181 cm, respectively. Therefore, the robot moved to location '\(b_{B}\)' that is located well past the nearby obstacle. Then, the robot was again placed in the same initial position (i.e., '\(b_{1}\)') with enabled MIS. This time the robot was commanded with the same voice instruction accompanied with a pointing gesture that expresses the intention of the user is not to move the robot to a location well past the nearby obstacle. Here, the \(D_{gesture}\) was 57 cm, that lead to assigning of \(D_{a,min}\) to \(D\) since \(D_{gesture}<\delta_{min}D_{r}\). The evaluated \(D_{a,min}\) was 72 cm since the robot considers the distance to the nearby obstacle in the considered field along the intended moving direction. Therefore, the quantified output was 48 cm, which resulted the movement of the robot to location '\(b_{A}\)' where the robot is not required to move beyond the nearby obstacle. In case (c), the initial position is location '\(c_{1}\)' and it was commanded, \"move far forward\".