• 로봇학회논문지
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• 제19권1호
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• pp.1-7
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• 2024

This paper presents an under-actuated robotic hand inspired by the ligamentous structure of the human hand for a prosthetic application. The joint mechanisms are based on the concept of a tensegrity structure formed by elastic strings. These rigid bodies and elastic strings in the mechanism emulate the phalanx bones and primary ligaments found in human finger joints. As a result, the proposed hand inherently possesses compliant characteristics, ensuring robust adaptability during grasping and when interacting with physical environments. For the practical implementation of the tensegrity-based joint mechanism, we detail the installation of the strings and the routing of the driving tendon, which are related to extension and flexion, respectively. Additionally, we have designed the palm structure of the proposed hand to facilitate opposition and tripod grips between the fingers and thumb, taking into account the transverse arch of the human palm. In conclusion, we tested a prototype of the proposed hand to evaluate its motion and grasping capabilities.

• Archives of Plastic Surgery
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• 제46권5호
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• pp.491-491
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• 2019

• 대한의용생체공학회:의공학회지
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• 제26권5호
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• pp.257-264
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• 2005

This paper proposes an ionic polymer metal composite (IPMC) based artificial muscle to be applicable to the Myoelectric hand prosthesis. The IPMC consists of a thin polymer membrane with metal electrodes plated chemically on both faces, and it is widely applying to the artificial muscle because it is driven by relatively low input voltage. The control commands for the IPMC-based artificial muscle is given by electromyographic (EMG) signals obtained from human forearm. By an intended contraction of the human flexor carpi ulnaris and extensor carpi ulnaris muscles, we investigated the actuation behavior of the IPMC-based artificial muscle. To obtain higher actuation force of the IPMC, the single layered as thick as $800[{\mu}m]$ or multi-layered IPMC of which each layer can be as thick as $178[{\mu}m]$ are prepared. As a result, the bending force was up to the maximum 12[gf] from 1[gf] by actuating the single layered IPMC with $178[{\mu}m]$, but the bending displacement was reduced to 6[mm] from 30[mm]. The experimental results using an implemented IPMC control system show a possibility and a usability of the bio-mimetic artificial muscle.

• 대한전기학회논문지:시스템및제어부문D
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• 제55권12호
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• pp.550-557
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• 2006

This paper proposes a dry-type surface myoelectric sensor for the myoelectric hand prosthesis. The designed surface myoelectric sensor is composed of skin interface and processing circuits. The skin interface has one reference and two input electrodes, and the reference electrode is located in the center of two input electrodes. In this paper is proposed two types of sensors with the circle- and bar-shaped reference electrode, but all input electrodes are the bar-shaped. The metal material of the electrodes is the stainless steel (SUS440) that endures sweat and wet conditions. Considering the conduction velocity and the median frequency of the myoelectric signal, the inter-electrode distance (IED) between two input electrodes as 18mm, 20mm, and 22mm is selected. The signal processing circuit consists of a differential amplifier with a band pass filter, a band rejection filter for rejecting 60Hz power-line noise, amplifiers, and a mean absolute value(MAV) circuit. Using SUS440, six prototype skin interface with different reference electrode shape and IED is fabricated, and their output characteristics are evaluated by output signal obtained from the forearm of a healthy subject. The experimental results show that the skin interface with parallel bar shape and the 18mm IED has a good output characteristics. The fabricated dry-type surface myoelectric sensor is evaluated for the upper-limb amputee.

• 한국의류학회지
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• 제44권4호
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• pp.610-625
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• 2020

This study suggests an alternative breast-prosthesis-making process for female breast cancer patients. From June 2018 to July 2018, we conducted a study using nine females between the ages 40-50 who never had breast cancer. We recorded the reported subjective sensations and objective physiological responses to different types of artificial breast materials: Trulife silicon breast prostheses (TS) and hand-made silk breast prostheses (HS). Considering the materials used in TS and HS individually, we studied the subjective sensation with regards to how each material functioned in a photo (VP), movement (VM) and the visual tactility (VT) sense. The results showed that comparing VP and VT led to more significant differences than those comparing VM and VT. In addition, there was a significant difference in terms of tactile sensation when comparing TS and HS with respect to subjective responses to texture. Subjects reported that HS felt more comfortable and gave a better cooling sensation. However, the measured objective physiological responses indicated that skin temperature was higher with HS than TS when touched. This research contributes to scholarship around alternative and new materials to build breast prostheses for women with breast cancer.

• 대한의용생체공학회:의공학회지
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• 제12권4호
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• pp.285-294
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• 1991

Two types of the speech signal processores (SSP) for the cochlear a prosthesis are designed. One is designed using the cochlear model and the other is designed using the information (formant, pitch, intensity) extraction method. For these, some cochlear model and acoustic information extraction method are proposed. The result shows the SSP of the cochlear model type contain more acoustic cues than that of information extraction type. On the other hand, stimulus signal is clear and algorithm is simple in the SSP of the information ex traction type.

• 대한치과기공학회지
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• 제25권1호
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• pp.111-118
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• 2003

I measured the movement range on the hinge articulator and the movement range in an oral. And then I studied to analyze the gap. I got wax records by the movement on the hinge articulator, the movement in an oral and the movement on the hand articulating. I measured the distance of the cusp tips that are close to the mesial direction and the distal direction, the buccal direction and the lingual direction then I compared gaps. As I saw results on data, I knew that the hinge articulator represented the range of mandibular movement restrictively. I could find the decisive contradiction that the sliding movement finished on the hinge articulator although it did not finish in an oral. If the sliding movement does not reappear exactly, it brings a fatal failure to the dental prosthesis. In addition it is impossible that the hinge articulator restores the movement in an oral because the lateral condyle inclination and the horizontal condyle inclination are fixed previously. Therefore dental prosthesisses were made by the hinge articulator, they will interfere with a mastication. I have obtained the following results; 1. The distance of sliding movement on the hinge articulator showed shorter than the distance of sliding movement in oral. This means the increase of cusp inclination of the dental prosthesis that was made on the hinge articulator. Therefore, when the lateral movement occurs in oral, there is a possibility to become the premature as the increase of cusp inclination. 2. The results that were impressed records in oral and impressed records on the hand articulating have many congruities. I think that the simple crown etc. that were made by the hand articulating method except the long span bridge and the free end case that can not measure the vertical dimension exactly can represent similarly the mandibular movement. 3. If we want to represent the mandibular movement similarly, we have to use the articulator that can adjust the horizontal condyle inclination and the lateral condyle inclination at least.

• 대한치과보철학회지
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• 제45권6호
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• pp.717-723
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• 2007

Statement of problem. Unreasonable distal cantilevered implant-supported prosthesis can mask functional problems of reconstruction temporarily, but it can cause serious strain and stress around its supported implant and surrounding alveolar bone. Purpose. The purpose of this study was to evaluate strain of implants supporting distal cantilevered fixed prosthesis with two different cantilevered length under distal cantilevered static load. Material and methods. A partially edentulous mandibular test model was fabricated with auto-polymerizing resin (POLYUROCK; Metalor technologies, Stuttgart, Swiss) and artificial denture teeth (Endura; Shofu inc., Kyoto, Japan). Two implants-supported 5-unit screw-retained cantilevered fixed prosthesis was made using standard methods with Type III gold alloy (Harmony C&B55; Ivoclar-vivadent, Liechtenstein, Germany) for superstructure and reinforced hard resin (Tescera; Ivoclar-vivadent, Liechtenstein, Germany) for occlusal material. Two strain gauges (KFG-1-120-C1-11L1M2R; KYOWA electronic instruments, Tokyo, Japan) were then attached to the mesial and the distal surface of each standard abutment with adhesive (M-bond 200; Tokuyama, Tokyo, Japan). Total four strain gauges were attached to test model and connected to dynamic signal conditioning strain amplifier (CTA1000; Curiotech inc., Paju, Korea). The stepped $20{\sim}100$ N in 25 N increments, cantilevered static load 8mm apart (Group I) or 16mm apart (Group II), were applied using digital push-pull gauge (Push-Pull Scale & Digital Force Gauge, Axis inc., Seoul, Korea). Each step was performed ten times and every strain signal was monitored and recorded. Results. In case of Group I, the strain values were surveyed by $80.7{\sim}353.8{\mu}m$ in Ch1, $7.5{\sim}47.9{\mu}m/m$ in Ch2, $45.7{\sim}278.6{\mu}m/m$ in Ch3 and $-212.2{\sim}718.7{\mu}m/m$ in Ch4 depending on increasing cantilevered static load. On the other hand, the strain values of Group II were surveyed by $149.9{\sim}612.8{\mu}m/m$ in Ch1, $26.0{\sim}168.5{\mu}m/m$ in Ch2, $114.3{\sim}632.3{\mu}m/m$ in Ch3, and $-323.2{\sim}-894.7{\mu}m/m$ in Ch4. Conclusion. A comparative statistical analysis using paired sample t-test about Group I Vs Group II under distal cantilevered load shows that there are statistical significant differences for all 4 channels (P<0.05).

• 한국산업융합학회 논문집
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• 제26권4_2호
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• pp.561-570
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• 2023

This study was to evaluate the effect of different rinsing times and methods on the accuracy of temporary prostheses fabricated by 3D printing method. Sixty temporary prostheses were fabricated with LCD types of 3D printer(Halot-Sky, Creality, Shenzhen, China) and divided into six groups (n = 10) based on rinsing times and methods. All specimens were rinsed with 99% isopropanol alcohol for 5 and 10 min using three methods-hand washed, ultrasonic cleaning, and automated washing. All specimens were polymerized for 3 minutes under the same conditions. The marginal and internal gaps of specimens were examined using a replica technique. The light-body silicone thickness was measured at 6 reference points(Absolute marginal discrepancy, Marginal, Chamfer, Axial, Angle, and Occlusal gap). All measurements were performed by a stereomicroscope. Reference point images were taken at 100× magnification and then measured using an image analysis program. Statistical analysis was performed using Two-way ANOVA, One-way ANOVA, and the Kruskal-Wallis test (p = .05). The marginal and internal gaps were statistically different according to the rinsing methods and rinsing times(p < .001). In the rinsing time, the temporary prosthesis rinsed for 5 minutes group showed higher accuracy than 10 minutes group. In the rinsing method, the hand washing group showed higher accuracy than the automated washing group.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 추계학술대회
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• pp.369-372
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• 1997

Socket pressure distributions with gait analyses of a transfemoral and a transtibial prostheses were measured in order to assess an optimal socket fitting and unction. Ankle joint was aligned by the neutral and the dorsi/plantar flexed positions. Compared to dorsi and plantar flexed positions of ankle joint, cadence and walking speed increased with the neutral ankle joint alignment. Other gait parameters were close to the normative data with the neutral ankle joint alignment. For the transfemoral amputee, dorsiflexed alignment of the ankle joint created high pressure on the lateral aspect of the socket, on the other hand, plantarflexed alignment resulted in increased pressure on the medial aspect of the socket. For the transtibial amputee, dorsiflexed alignment of the ankle resulted in high pressure on the antero-lateral aspect of the socket during mid-stance, but plantarflexion of the ankle joint showed slight increases in pressure at the same location in the socket. The present study clearly demonstrated that malalignment of a prosthesis results in localized increasing pressure within the socket. Proper alignment of the prosthesis is required in order to acquire an appropriate socket-limb interface as well as the proper gait.