• Archives of Reconstructive Microsurgery
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• v.22 no.2
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• pp.78-81
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• 2013

Neurofibroma may present as a solitary lesion or as multiple lesions. Although there is no site of predilection for solitary lesions, occurrence on the hand is rare. Plexiform neurofibroma can develop in isolation or more commonly as a part of neurofibromatosis type 1. In those that apper in isolation, trauma has been suggested as a precipitating factor. A 68-year-old male farmer had experienced repetitive prior episodes of trauma in the involved finger. He presented with a painless mass on the dorsal aspect of the fifth finger. Physical examination showed a protruding mass measuring approximately $15{\times}20mm$ which was not tenderness to palpation and any skin changes or pigmentation. Ultrasonography showed a cystic mass on the dorsal aspect of the middle phalanx. Microsurgical dissection was applied in order to seperated the lesion from the ulnar side of the dorsal branch of the digital nerve. Pathologic examination of the specimens revealed neurofibroma. At three-month follow-up, motor and sensory function were intact, and range of motion was fully recovered. Traumatic solitary neurofibroma is a rare tumor of the hand, especially in the finger. Hand surgeons should be aware of the diagnostic possibilities of this tumor based on examination, history taking and imaging studies.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.1 s.232
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• pp.1-13
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• 2005

Kinematics of grasping and manipulation by a multi-fingered robotic hand where multi-fingertip surfaces are in contact with an object is solved. The surface of the object was represented by B-spline surfaces in order to model the objects of various shapes. The fingers were modeled by cylindrical links and a half ellipsoid fingertip. Geometric equations of contact locations have been solved for all possible contact combinations between the fingertip surface and the object. The simulation system calculated joint displacements and contact locations for a given trajectory of the object. Since there are no closed form solutions for contact or intersection between these surfaces, kinematics of grasping was solved by recursive numerical calculation. The initial estimate of the contact point was obtained by approximating the B-spline surface to a polyhedron. As for the simulation of manipulation, exact contact locations were updated by solving the contact equations according to the given contact states such as pure rolling, twist-rolling or slide-twist-rolling. Several simulation examples of grasping and manipulation are presented.

• The Journal of Korea Robotics Society
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• v.17 no.4
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• pp.484-492
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• 2022

This paper presents a simple and robust under-actuated robotic finger mechanism that enables self-adaptive grip, fingertip pinch, and caging grasp functions. In order to perform daily activities using hands, the fingers should be able to perform adaptive gripping and pinching motion, and the caging grasp function is required to realize natural gripping motions and improve grip reliability. However, general commercial prosthetic hands cannot implement all three functions because they use under-actuation mechanism and simple mechanical structure to achieve light-weight and high robustness characteristic. In this paper, new mechanism is proposed that maintains structural simplicity and implements all the three finger functions with simple one degree-of-freedom control through a combination of a four-bar linkage mechanism and a wire-driven mechanism. The basic structure and operating principle of the proposed finger mechanism were explained, and simulation and experiments using the prototype were conducted to verify the gripping performance of the proposed finger mechanism.

• The Journal of Korean Medical History
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• v.35 no.1
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• pp.87-99
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• 2022

The purpose of this paper is to test the hypothesis that some early Chinese meridians were described by haptic exploration of the arterial pulse. The method is as follows: First, the relevant passages of the Mawangdui medical texts, the oldest meridian monographs, are translated based on perceptual anatomy. Second, the pulse is haptically searched for in the palm, lower arm, upper arm, armpit, and torso of the human body. Finally, their locations are compared with the translation. As a result, It was confirmed that the pulse locations detected on the body were mostly consistent with the routes of the meridians described in the texts. So meridians were haptically detectable pulse routes. What is known today as the flow direction of hand-yin meridians is actually the direction of searching the pulse. Our result runs counter to Huang Longxiang's claim that the route of the meridians are virtual routes set by speculation. Our findings also dispute Vivien Shaw's claim that the meridians of Mawangdui medical texts were discovered by anatomical dissection. They also refute the claim that meridians were discovered by the extrasensory perception of the inner sight (內觀) and the subjective experience of the meridian sensitive person. The hand-yin meridians of Mawangdui medical texts are well described so that anyone can find them by touching them with their fingers.

• Science of Emotion and Sensibility
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• v.14 no.4
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• pp.537-544
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• 2011

Tactile acuity was assessed in groups of control, blind, deaf, and blind caused by complication to investigate the effective tactile stimuli on tactile sensory substitution studies when tactile display is applied to persons with sensory loss of vision or hearing. Two-point discrimination and grating resolution were assessed by compass and JVP dome, respectively, in the hand, arm, neck, lumbar, and knee. In two-point discrimination by compass, control group showed the highest sensitivity in fingers among assessed body areas but did not show any significant difference between male and female. Blind group and deaf group compared to control group did not show any significant difference in fingers but showed lower sensitivity in arm and knee. In grating resolution by JVP dome, control group did not show any significant difference among five fingers as well as between male and female. Blind group showed higher sensitivity in five fingers compared to control group, but deaf group did not show any significant difference from control group. Blind caused by complication group showed lower sensitivity in two-point discrimination and grating resolution compared to control group and blind group. These results suggest that the body area and method of tactile stimulation, and difference in tactile acuity depending on underlying disease of sensory loss should be considered when tactile display is applied for sensory substitution.

• Journal of the Ergonomics Society of Korea
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• v.33 no.5
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• pp.395-405
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• 2014

Objective: The aim of this study is to investigate 1) somatotopic arrangement of the second and third fingers in SI area 2) difference of neural activation in the SI area produced by stimulation with different frequencies 3) correlation between the intensity of tactile perception by different stimulus intensity and the level of brain activation measurable by means of fMRI. Background: Somatosensory cortex can obtain the information of environmental stimuli about "where" (e.g., on the left palm), "what" (e.g., a book or a dog), and "how" (e.g., scrub gently or scrub roughly) to organism. However, compared to visual sense, the neural mechanism underlying the processing of specific electrotactile stimulus is still unknown. Method: 10 right-handed subjects participated in this study. Non-painful electrotactile stimuli were delivered to two different finger tips of right hand. Functional brain images were collected from 3.0T MRI using the single-shot EPI method. The scanning parameters were as follows: TR and TE were 3000, 35ms, respectively, flip angle 60, FOV $24{\times}24cm$, matrix size $64{\times}64$, slice thickness 4mm (no gap). SPM5 was used to analyze the fMRI data. Results: Significant activations produced by the stimulation were found in the SI, SII, the subcentral gyrus, the precentral gyrus, and the insula. In all participants, statistically significant activation was observed in the contralateral SI area and the bilateral SII areas by the stimulation on the fingers but ipsilaterally dominant. The SI area representing the second finger generally located in the more lateral and inferior side than that of the third finger across all the subjects. But no difference in brain area was found for the stimulation of the fingers by different frequencies. And two typical patterns were observed on the relationship between the perceived psychological intensity and the amount of voxels in the primary sensory cortex during the stimulation. Conclusion: It was possible to discriminate the representation sites in the SI by electrotactile stimulation of digit2 and digit3. But we could not find the differences of the brain areas according to different stimulation frequencies from 3 to 300Hz. Application: The results of the study can provide a deeper understanding of somatosensory cortex and offer the information for tactile display for blinds.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.7
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• pp.1349-1354
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• 2017

In this paper, we propose a fast hand-gesture recognition algorithm for embedded system. Existing hand-gesture recognition algorithm has a difficulty to use in a low performance system such as embedded systems and mobile devices because of high computational complexity of contour tracing method that extracts all points of hand contour. Instead of using algorithms based on contour tracing, the proposed algorithm uses concentric-circle tracing method to estimate the abstracted contour of fingers, then classify hand-gestures by extracting features. The proposed algorithm has an average recognition rate of 95% and an average execution time of 1.29ms, which shows a maximum performance improvement of 44% compared with algorithm using the existing contour tracing method. It is confirmed that the algorithm can be used in a low performance system such as embedded systems and mobile devices.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.11
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• pp.2273-2276
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• 2009

As parents are interested in music education for infants in these days, they require systems to help these infants to actively play music. In this paper, we propose a keyboard solo system using a real time hand recognition method. In order to enable the infants to use the system easily, the proposed system plays some sounds whenever the infants move their fingers on a paper piano. For the purpose of minimizing cost to play music, the proposed system utilizes a general PC with only a paper piano, a web camera, and a speaker. With the aim of precisely and efficiently recognizing both a hand and each key on keyboard, the proposed system divides a recognition step into a hand recognition step and a keyboard recognition step. Also, the hand recognition step considers only skin color, and the keyboard recognition step considers only black and white without other colors.

• Journal of Korea Multimedia Society
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• v.9 no.8
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• pp.1067-1075
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• 2006

This paper proposes a advanced representation method of hand motion by cheremes analysis in korean sign language. The proposed method is the representation method which apply to the hand motion used in KSL(Korean Sign Language) to represent rich and united hand motion. Words or sentences in KSL are completed by combination of elements called as Cheremes, that is, a hand movement orientation, a finger shape, a hand position, etc. In this paper, Cheremes composing the KSL is divided and represented by 5 elements: the hand movement orientation(HMO), finger shape(FS), hand orientation(HO), hand position(HP) and number of using hand (HN). Each cheremes is expressed by more various characteristics. For example, The hand movement orientation means orientations which the hand move while the sign language is done and can be expressed by 17orientation components. The finger shape means various shapes which fingers can take and represented by 17 components. The Orientation of hand is expressed by 2 characteristics according to whether we use the palm of the hand or the back. The position of hand means specific regions in body which hand(s) is placed while the sign language is done and divided by 8 regions. Finally, the number of hand means whether use only one hand or both hands and is expressed by 2 characteristics. The proposed method has been tested with KSL words and sentences and the results have shown that they can be expressed completely by the proposed representation method.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.6
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• pp.52-62
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• 1999

This paper presents a system which recognizes dynamic hand gestures on-line for controlling motion of numan avatar in virtual environment(VF). A dynamic hand gesture is a method of communication between a computer and a human being who uses gestures, especially both hands and fingers. A human avatar consists of 32 degree of freedom(DOF) for natural motion in VE and navigates by 8 pre-defined dynamic hand gestures. Inverse kinematics and dynamic kinematics are applied for real-time motion control of human avatar. In this paper, we apply a fuzzy min-max neural network and feature analysis method using fuzzy logic for on-line dynamic hand gesture recognition.