• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1303-1306
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• 2004

We developed a symmetrical upper limb motion trainer for chronic hemiparetic subjects. This trainer enabled the practice of a forearm pronatio $n^ination and wrist flexion/extension. In this study, we have used functional magnetic resonance imaging(fMRI) with the developed symmetrical upper limb motion device, to compare brain activation patterns elicited by flexion/extension wrist movements of control and hemiparetic subject group. In control group, contralateral somatosensory cortex(SMC) and bilateral cerebellum were activated by dominant hand movement(Task 1), while bilateral movements by dominant hand(Task 2) activated the SMC in both cerebral hemispheres and ipsilateral cerebellum. However, in hemiparetic subject group, contralateral supplymentary motor area(SMA) was activated by unaffected hand movement(Task 1), while the activation of bilateral movements by unaffected hand(Task 2) showed only SMA in the undamaged hemisphere. This study, demonstrating the ability to accurately measure activation in both sensory and motor cortex, is currently being extended to patients in clinical applications such as the recovery of motor function after stroke.ke.

• Journal of Educational Research in Mathematics
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• v.20 no.1
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• pp.21-43
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• 2010

In this article three types of neuro-biological epistemology have been studied and applied to mathematics. Nativism or innatism is favored by many evolutionary psychologists and some mathematicians. They believe domain specific brain functions or modules, particularly language faculty and number instinct in infants. Number/mathematical cognition is a new research area and scientists try to localize areas related with mathematics. Selectionism has adopted Darwinism to synapse growth and supports neuronal regression. Mathematical creativity can be explained using selectionism. Neural constructivism has originated from J. Piaget and supports neuronal/synapse growth in children or adults if adequate exercise and practise is given. Unlike Piaget, neural constructivists accepts the importance of structured experience for the reorganization of brain. Authors opinion is all these theories of epistemology is equally important and they all give insights on how the brain and self is made.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.10
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• pp.820-825
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• 2010

In this study, we intended to design the optimal Fermi filter to apply the k-space date that is knee image of the rheumatoid arthritis patient acquired from the MRI (magnetic resonance imaging) instrument. After deciding the suitable coefficient for the Fermi filter, the results were compared with modified Fermi filter and inverse Chebyshev filter, Chebyshev filter, Elliptic filter and Butterworth filter. Firstly, in comparison to the results, the radiologist confirmed that modified Fermi filter was best decision for boundary of the rheumatoid arthritis images. The number of the black voxels of the histogram showed the quantity of the results. At the proposed filter images, numbers of the blacks voxels were statistically decreased. That meant voxels only appeared the black color were changed to others voxels color. Because the number of the total voxels was fixed, the area appeared block color could be effected to the other areas. If the modified Fermi filter were used for rheumatoid arthritis patient, the result will be better than other filters.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.10
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• pp.1727-1730
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• 2016

Magnetic resonance imaging has a potential to produce clear anatomical as well as functional images of human body. However, the ability to diagnose is limited by signal to noise ratio (SNR) and the resolution of current medical systems. To remove the challenges prevalent due to the use of high field scanners, dedicated radio frequency coils are used. Transverse electromagnetic coils have an advantage of providing homogeneous magnetic field throughout the region but with low signal to noise ratio while surface coils have an advantage of providing higher signal to noise ratio but with low homogeneity. This research combines both the advantage into one by utilizing transmit only transverse electromagnetic radio frequency coils (8 channel) along with receive only surface coils (by varying the number) for better imaging of brain. A 7 Tesla 32-channel close fitting helmet shaped phased-array surface coils along with the combination of 8 channel transmit only transverse electromagnetic coils provided good homogeneity as well as significant SNR improvements throughout the human brain.

• Journal of Biosystems Engineering
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• v.28 no.3
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• pp.253-260
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• 2003

In this study, the feasibility of magnetic resonance techniques for nondestructive internal quality evaluation of Korean red ginseng was examined. Relaxation time constants were measured using various grades of red ginsengs. Solid state magnetic resonance imaging technique was applied to image dried red ginsengs which have low moisture contents (about 13%). A 7 tesla magnetic resonance imaging system operating at a proton resonant frequency of 300 ㎒ was used for acquiring MR images of dried Korean red ginseng. The comparison test of cross cut digital images and magnetic resonance images of heaven grade, good grade with cavity inside, and good grade with white part inside red ginseng suggested the feasibility of the internal quality evaluation of Korean red ginsengs using MRI techniques. A good grade red ginseng included abnormal tissues such as cavities or white parts inside was observed by the signal intensity of MR image based on magnetic resonance properties of proton nucleus. Analysis on an one dimensional profile of acquired MR image of Korean red ginseng showed easy discrimination of normal and abnormal tissues. MR techniques suggested ways to detect internal defects of red ginsengs effectively.

• Journal of Biomedical Engineering Research
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• v.28 no.1
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• pp.75-83
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• 2007

Elasticity is an important physical property of biological tissues. Differences in elasticity can help facilitate the diagnosis of tumors and their extent. Magnetic Resonance Elastography (MRE) tries to visualize images of tissue elasticity by externally applying shear stress on the surface of an imaging object. Applied shear stress induces internal displacements that can be measured from MR phase images. In order to conduct MRE imaging experiments, we need to first develop a vibrator. We found that there does not exist enough technical information to design the MRE vibrator. In this paper, we describe the theory, design and construction of an MRE vibrator. We report the performance of the developed vibrator using two different test methods. We found that the vibrator successfully induces enough internal displacements that can be imaged using an MRI scanner. We suggest future studies of numerous MRE imaging experiments using the vibrator.

• Journal of the Korean Arthroscopy Society
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• v.14 no.1
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• pp.45-48
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• 2010

We report a case of an 85-year-old woman with tuberculous subdeltoid bursitis. Tubeculous bursitis without adjacent joint tuberculosis may occur any site but it is rare. It is common in bursae subjected to trauma like trochanteric, prepatellar, olecranon and so on. Because the clinical findings or physical examination of tuberculous subdeltoid bursitis are similar to rotator cuff disorder and the MRI or arthroscopic findings are similar to synovial diseases, careful differential diagnosis is necessary.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.227-229
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• 1997

A new phased-array quadrature RF coil for one or two RF acquisition channels is developed for spine MR imaging. Quadrature RF coils for MRI have been useful to improve the signal-to-noise ratio (SNR) by $"\sqrt{2}"$ using two orthogonal RF coils in combination [1]. More recently, the phased-array RF coil has been proposed for more improvement of SNR by using an array of RF coil elements with a reduced size and coverage for each element. Two new schemes are proposed for the new phased-array quadrature RF coil as follows : (1) Proper overlapping of two quadrature RF coils thus removing the mutual inductance and (2) Attaching preamplifiers right after the coil section and combining the signal with proper phase delays. The coil has been implemented for receive- only mode. It has been tested through phantom and volunteer imaging. The experimental results show the utility of the proposed RF coil.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.27 no.1
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• pp.263-271
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• 1997

The authors diagnosed a 54-year-old male as central mucoepidennoid carcinoma after undergoing clinical, radiological and histopathological examinations. The characteristics were as followed : 1. Clinically, the patient complained of the painless unilateral swelling of the left mandibular molar region and had a pus discharge through the fistula. Painful nodule was palpated on the scalp of the left frontal area and it was regarded as a metastatic lesion. 2. Plain radiographs showed the ill-defined permeative radiolucent lesion. The osteolytic lesions were also detected in the cranial bone, number 9 and 11 ribs, scapula, and vertebral bodies. 3. The mandibular CT and PNS MRI showed the swelling of the left mandible and the enlargement of the several lymph nodes of 1.5 cm in size. 4. Histopathologically, many solid epidermoid type cells were mixed with mucus-secreting cells and they were arranged in duct-like structure. Most of them were epidermoid type, which indicates a high grade tumor. Mucins could be found in mucicamrine staining.

• Journal of the Korean Arthroscopy Society
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• v.12 no.1
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• pp.63-65
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• 2008

We treated a 37-year-old male with traumatic hematoma in the suprapatellar bursa that had developed in the form of persistent swelling on suprapatellar area of left knee after blunt trauma. Though there were no obvious abnormal findings on plain roentgenographs, an isolated suprapatellar cystic lesion with fluid-fluid level on T2-weighted sagittal image of MRI was noted. We found the suprapatellar plica with complete septum and no synovitis in the knee joint proper by arthroscopy. We incised the plica and found leakage of blood-stained fluid from the suprapatellar bursa. There were no findings of pigmented villonodular synovitis or other tumorous lesions. At 6 months after surgery, the patient felt symptom-free and there was no recurrence.