## 2 Materials and Methods
### Individual Application Method according to User Attachment of the Fabricated Sensor
#### 2.2.2 Cutting the Outer Part of the Sensor according to the Flexion of Attachment Areas  
Professor [PERSON] et al. aimed to verify pressure changes according to five locomotion movements by attaching a small pressure sensor inside the socket [28]. The  
Figure 2: Initial setting of the measurement value of the sensor to account for individual pressure ranges: (**a**) determination of individual pressure ranges inside the socket with or without load from the prosthetic user; (**b**) calculation of pressure changes based on the initial pressure presented by the body load. small-sized sensor applied by the research team was located only in a local area of the amputated muscle, with reduced muscle contraction and relaxation ability. As a result, reproducibility was degraded when the position of the lower limb changed inside the socket. In conclusion, sensors that detect intention based on the movement of the lower limb inside the socket should be applied in a large area rather than a narrow and specific region. However, a large-sized sensor causes an unfastened state in which it does not adhere to the inner surface of the socket, where flexion exists. The unfastened state reduces the reproducibility by causing shape deformation, such as wrinkles on the sensor. This problem can be solved by cutting the outside of the sensor. The wider the cut shape, the easier it is to resolve the unfastened state. However, this causes the excessive loss of the sensor area, as shown in Figure 3b. The optimal amount of cutting, with little loss of the sensor and without the occurrence of the unfastened state, as proposed in this paper, is within 10% of the total sensor area. If cutting is carried out in excess of 10%, there is a risk of not detecting pressure changes due to the loss of the sensor area. Figure 3c shows a triangular cut shape to resolve the unfastened state. Figure 3d shows the results of a simple experiment comparing the pressure measurement pattern according to the presence or absence of a sensor cut. If an uncut sensor is attached to a curved surface, the conductive layer of the sensor is compressed, and an overpower value exceeding the initial power range appears even when the pressure is not applied. This reduces the detection resolution of the sensor. In comparison, the cut sensor has a low initial measurement voltage of 1 V or less, resulting in a wide range of pressure changes. Through this, it can be confirmed that the cutting of the sensor is necessary according to the flexion of the attachment area. The minimum area of cutting according to the flexion section is presented as a production guideline through experiments in Section 3. Figure 3e shows the results of the experiment to determine whether the pressure measurement characteristics are maintained according to the presence or absence of cutting in the outer part. The pressure measurement characteristics of the Velostat film pressure sensor, which was processed by cutting the outer part, were maintained at the same values as before the cutting. To verify this, cutting was performed on only one of the two sensors of the same size, and an experiment was conducted to compare the pressure measurement characteristics by applying the same pressure. Figure 3e shows the results of comparing the pressure measurement characteristics of  
Figure 3: Cutting the outer part of the sensor to address the unfastened state. (**a**) sensor before cutting: it does not adhere to the inside of the socket; (**b**) sensor after excessive cutting: excessive gaps due to increased sensor loss area; (**c**) sensor after cutting: increased sensor adhesion by cutting where the unfastened state occurs; (**d**) comparison of the pressure change range with or without sensor cutting; (**e**) results of the experiment aimed at maintaining the pressure measurement characteristics according to the outer part cutting. the uncut and cut sensors fabricated at the same 2500 mm\({}^{2}\) size. The cut was composed of a triangle, 5 mm wide and 10 mm long, on each of the four sides of the sensor.