• The Korean Journal of Physiology
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• v.24 no.1
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• pp.103-113
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• 1990

The role of cervical proprioceptors in the control of body posture was studied in bilaterally labyrinth-ectomized, decerebrate cats. The animals were suspended on hip pins with the neck extended horizontally. With this placement the EMG activities of extensor and flexor muscles of the upper extremities were observed by means of sinusoidal head rotator. The rotator can induce two kinds of neck movement: The one is 'pitch' which describes a rotatory neck motion to transverse axis of the body and mainly occurs at skull-C1 (atlantooccipital) joint and the other is 'roll', side-to-side relation of the neck to longitudinal axis, whose center is C1-C2 (atlanto-axial) joint. The following results were obtained. 1) Responses of EMG activity were closely dependent on the rotatory range of the neck. And the EMG activity was not changed during sustained neck torsion, eliciting a typical tonic neck reflex. 2) On pitching movement, the head-up rotation produced the excitation of bilateral triceps muscles, whereas the head-down rotation produced the inhibition. And the response of bilateral biceps muscles was the opposite to that of triceps. 3) On rolling movement, the side-up rotation of the head produced the excitation of ipsilateral triceps muscles and the inhibition of contralateral ones. And the response of biceps muscles was the opposite to that of triceps. 4) The minimum requirement of motion to evoke EMG activities in the upper extremities was $3.2^{\circ}{\sim}12.5^{\circ}$. These results have shown that the cervical proprioceptors produce tonic discharge on the upper brachial muscles, regulate the EMG activities of those muscles, and are very sensitive to neck rotation. And it can be stated that the cervical proprioceptors may play an important role in the control of body posture and movement.

• Investigative Magnetic Resonance Imaging
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• v.23 no.1
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• pp.38-45
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• 2019

Purpose: To demonstrate the high-resolution numerical simulation of the respiration-induced dynamic $B_0$ shift in the head using generalized susceptibility voxel convolution (gSVC). Materials and Methods: Previous dynamic $B_0$ simulation research has been limited to low-resolution numerical models due to the large computational demands of conventional Fourier-based $B_0$ calculation methods. Here, we show that a recently-proposed gSVC method can simulate dynamic $B_0$ maps from a realistic breathing human body model with high spatiotemporal resolution in a time-efficient manner. For a human body model, we used the Extended Cardiac And Torso (XCAT) phantom originally developed for computed tomography. The spatial resolution (voxel size) was kept isotropic and varied from 1 to 10 mm. We calculated $B_0$ maps in the brain of the model at 10 equally spaced points in a respiration cycle and analyzed the spatial gradients of each of them. The results were compared with experimental measurements in the literature. Results: The simulation predicted a maximum temporal variation of the $B_0$ shift in the brain of about 7 Hz at 7T. The magnitudes of the respiration-induced $B_0$ gradient in the x (right/left), y (anterior/posterior), and z (head/feet) directions determined by volumetric linear fitting, were < 0.01 Hz/cm, 0.18 Hz/cm, and 0.26 Hz/cm, respectively. These compared favorably with previous reports. We found that simulation voxel sizes greater than 5 mm can produce unreliable results. Conclusion: We have presented an efficient simulation framework for respiration-induced $B_0$ variation in the head. The method can be used to predict $B_0$ shifts with high spatiotemporal resolution under different breathing conditions and aid in the design of dynamic $B_0$ compensation strategies.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.32 no.1
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• pp.39-42
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• 2021

Granuloma is an uncommon benign disease that develops in the process of wound healing. Pharyngeal or laryngeal granuloma can be associated with gastric reflux, mechanical injury or trauma including intubation, voice abuse, or foreign body. 50-year-old female was transferred to our institute with a huge mass occupying the upper aerodigestive tract causing dysphagia. The patient has been suffering from a brain hemorrhage for several months and was kept in bed due to the quadriplegia with stuporous mental status, and was tracheotomized. On examination, the whole oropharynx and hypopharynx was covered by a smooth-surfaced soft big diffuse granular mass, which extended down to the upper trachea through the larynx. The huge granuloma was successfully removed with surgery and was found to have a pedunculating stalk on the oropharyngeal posterior wall with a small mucosal defect, suggestive of the origin of the mass. The defect was closed primarily after the cauterization. The patient is now followed up regularly without any recurrence of the disease.

• Journal of Oral Medicine and Pain
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• v.25 no.1
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• pp.99-108
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• 2000

This study was performed to investigate the effect of suboccipital stretch on the head and neck posture and the electromyographic(EMG) activity of some cervical muscles. For this study, 39 patients with temporomandibular disorders(TMD) and 34 dental students without any signs and symptoms in the masticatory system were selected as the patients group and as the normal group, respectively. Head position by goniometer CROM$^{(R)}$(Performance attainment, St. Paul, USA), EMG activity by BioEMG$^{(R)}$(Bioresearch Inc., Milwaukee, USA), and craniocervical posture by cephaloradiography were observed in both natural head posture(NHP) and head posture with suboccipital stretch(tuck posture) abtained from slight posteroinferior finger pressure on the chin. Variables measured on the cephaloradiograph were SN angle, atlas angle, CVT angle, occiput-atlas and atlas-axis distance, and pharyngeal width. The data obtained were analysed by SPSS windows program and the results of this study were as follows : 1. In the sagittal plane, degree of anterior rotation of the head by suboccipital stretch was 6.3 in the patients group, and 6.2 in the normal group, respectively. So there was no significant difference between the two groups for degree of anterior rotation, but the position of the head in the patients group were more posteriorly extended than in the normal group in both NHP and tuck posture. 2. EMG activity of the stemocleidomastoideus in the patients group, and that of the upper trapezius and the sternocleidomastoideus in the normal group were increased by suboccipital stretch. The range of EMG activity, however, in these cervical muscles were 1.6 -2.3)u.V. 3. Cephalometric variables such as SN angle, atlas angle, CVT angle, occiput-atlas and atlas-axis distance except pharyngeal width were generally increased by suboccipital stretch. There was some difference, however, in results between the two groups. Atlas angle was not changed in the patients group whereas CVT angle was not changed in the normal group. 4. The distance from subocciput to spinous process of axis was significantly increased as much as 3.0mm in the patients group, and 3.7mm in the normal group by suboccipital stretch.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.141-146
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• 1999

This study aims at establishing an digital signal processing technique to control 3-D sound localization, especially focusing our eyes on the role of information provided by Head-Related Transfer Function(HRTF). In order to clarify the cues to control the auditory distance perception, two conventional models named Hirsch-Tahara model and auditory parallax model were examined. As a result, it was shown that both models have limitations to universally explain the auditory distance perception. Hence, the auditory parallax model was extended so as to apply in broader cases of auditory distance perception. The results of the experiment by simulating HRTFs based on the extented parallax model showed that the cues provided by the new model were almost sufficient to control the perception of auditory distance from an actual sound source located within about 2 m.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.7
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• pp.62-70
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• 2015

The energy of a sensor in a Wireless Sensor Network (WSN) puts a limit on the lifetime of the network. To prolong the lifetime, a clustering plan is used. Clustering technology gets its energy efficiency through reducing the number of communication occurrences between the sensors and the base station (BS). In the distributed clustering protocol, LEACH-like (Low Energy Adaptive Clustering Hierarchy - like), the number of sensor's cluster head (CH) roles is different depending on the sensor's residual energy, which prolongs the time at which half of nodes die (HNA) and network lifetime. The position of the CH in each cluster tends to be at the center of the side close to BS, which forces cluster members to consume more energy to send data to the CH. In this paper, a protocol, pseudo-LEACH, is proposed, in which a cluster with a CH placed at the center of the cluster is formed. The scheme used allows the network to consume less energy. As a result, the timing of the HNA is extended and the stable network period increases at about 10% as shown by the simulation using MATLAB.

• Korean Journal of Head & Neck Oncology
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• v.14 no.1
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• pp.88-93
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• 1998

In order to review the clinicopathologic characteristics of the thyroid cancer associated with benign thyroid disease, we evaluated 47 patients treated between January, 1993 and September, 1997 at the Chonnam National University Hospital. In those period, we had operated a total of 690 thyroidectomy of which 320 were diagnosed as thyroid cancer. Forty three(91.4%)occurred in women and four(8.5%)occurred in men. The mean age at operation was 46.7years(range, 15 to 76 years). Forty three of the 47 cancers(91.4%) were papillary carcinomas while 4(8.5%)were follicular. Twenty four of the 47 patients (51%) were occult thyroid carcinomas measured less than 1 cm in diameter. The concurrent benign disease were nodular goiter(n=17), Hashimoto's thyroiditis(n=16), follicular adenoma(n=10), Graves' disease(n=2) and diffuse hyperplasia(n=2). Thirty one patients were diagnosed by preoperative FNAC and they underwent total thyroidectomy. Three were diagnosed by frozen section examination at the time of operation. Among them, one underwent total thyroidectomy and two underwent subtotal thyroidectomy. Eight cases revealed lymph node metastases and 2 cases extended to surrounding muscles. In conclusion, concurrent thyroid cancers and benign thyroid disease are not uncommon and a regular ultrasonic follow-up with selective aspiration cytologic examination is recommaned to enhance their diagnostic accuracy.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.6
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• pp.776-787
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• 1998

This paper analyzes the local specific absorption rates (SAR's) averaged over 1 g and 10 g in a human head model in contact with a mobile phone operating at 835 MHz. The used numerical method is a total field finite-difference time-domain (FDTD) technique. The phone was simulated with a conducting box, a plastic case, and a whip antennal composed of a monopole and a helix. The discrete human model of the spatial resolution 3 mm is based on Magnetic Resonance Imaging (MRI), computerized tomography (CT) and anatomical images. The near field and far field and far field patterns were analyzed for extended and retracted phone. The two methods to take the volumes of the weights, 1 g or 10 g in tissue are proposed and compared to offer a reproductive technique for SAR estimations.

• Korean Journal of Head & Neck Oncology
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• v.3 no.1
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• pp.71-78
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• 1987

The supraglottic subtotal laryngectomy represents a conservation laryngeal procedure in which the upper portion of the larynx is removed without sacrificing the normal functions of the remaining larynx. The basis for this procedure rests in the embryologic derivation and consequent anatomic compartmentalization of the larynx and its lymphatics, which limit tumor spread. This procedure is performed for carcinoma involving the epiglottis and false cords, and can be extended to include carcinomas of the aryepiglottic fold and the anterior and lateral walls of the pyriform sinus and selected lesions involving the vallecula and base of the tongue. Recently the authors has experienced 4 cases of supraglottic cancer, which were performed supraglottic subtotal laryngectomy. One of which was died because of local recurrence, and the remaining cases were successful with satisfactory rehabilitation without local recurrence and impairment of voice and swallowing.

• Korean Journal of Head & Neck Oncology
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• v.10 no.2
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• pp.171-177
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• 1994

We reviewed retrospectively 152 patients' records with salivary gland tumors confirmed histologically at Hanyang University Hospital from Jan. 1984 to Dec. 1993. The results obtained were as follows: 1) Sites of tumors were parotid gland in 102 cases(67%), submandibular gland in 29 cases(19%) and minor salivary glands in 21 cases (14%). 2) 113 cases(74%) were benign. and 39 cases(26%) were malignant. 3) The incidence of benign and malignant tumors were 81% & 19%, 69% & 31% and 48% & 52% in the parotid gland, the submandibular gland and the minor salivary glands respectively. 4) The most frequent histologic types of benign and malignant tumors were pleomorphic adenoma (64%) and mucoepidermoid carcinoma (11%) respectively. 5) The surgical procedures include superficial parotidectomy. total parotidectomy. extended total parotidectomy & neck dissection in the parotid gland. wide excision & neck dissection in the submandibular gland and wide excision, partial maxillectomy & neck dissection in the minor salivary glands. 6) The postoperative recurrence rate were 4.4% in benign tumors and 27% in malignant tumors.