• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.1
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• pp.94-100
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• 1988

To improve the switching time of active optical bistable devices, we propose an active optical bistable device that consists of a diode laser, a transistor, and a photodetector. By implementing the proposed device we realize the optical bistable device with a 5 nanosecond switching time. This is the fastest switching time among the hybrid type optical bistable devices. It is also experimentally demonstrated that the proposed device may be used in an optical disc pick up.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.831-833
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• 2003

BLDC (Blush-Less Direct Current) motors are widely used for machine tools and ODD (Optic Disc Drive). Topology Optimization is applied to the rotor of a BLDC motor to improve in efficiency and save money. Density method and design sensitivity are derived. The result of topology optimization shows better performance.

• Journal of The Korean Ophthalmological Society
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• v.59 no.11
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• pp.1097-1102
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• 2018

Purpose: To report a case of toxic optic neuropathy caused by chlorfenapyr ingestion accompanied by central nervous system involvement. Case summary: A 44-year-old female visited our clinic complaining of reduced visual acuity in both eyes for 7 days. She had ingested a mouthful of chlorfenapyr for a suicide attempt 2 weeks prior to the visit. Gastric lavage was performed immediately after ingestion at the other hospital. Her best-corrected visual acuity was finger count 30 cm in the right eye and hand motion in the left eye. Both pupils were dilated by 5.0 mm and the response to light was sluggish in both eyes. A relative afferent pupillary defect was detected in her left eye. Funduscopy revealed optic disc swelling in both eyes. Magnetic resonance imaging of the brain showed a symmetric hyper-intense signal in the white matter tract including the internal capsule, corpus callosum, middle cerebellar peduncle, and brainstem. The patient was diagnosed with toxic optic neuropathy induced by chlorfenapyr ingestion, and underwent high-dose intravenous corticosteroid pulse therapy. Three days later, the best-corrected visual acuity was no light perception in both eyes. Three months later, optic atrophy was observed in both eyes. Optical coherence tomography revealed a reduction in the thicknesses of the retinal nerve fiber layer and ganglion cell and inner plexiform layer in the macular area. Conclusions: Ingestion of even a small amount of chlorfenapyr can cause severe optic nerve damage through the latent period, despite prompt lavage and high-dose steroid treatment.

• Korean Journal of Veterinary Pathology
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• v.7 no.1
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• pp.17-21
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• 2003

From February to September in 1996, a lot of blind cattle were reported in Dangjin Area of Chungnam Province. Blindness were observed in the 143 calves of the 1,496 calves from 79 farms. Blind cattle were found only in the farms where green pasture was not fed. After administration of vitamin A as the type of feed additives and parenteral injection, the blindness cases were not occurred in those farms. Both pupils were totally dilated with the absence of pupillary light reflex in all blind cattle. In the ophthalmoscopic examination, the fundus revealed multi focal linear white mottling which was more severe in nontapetal fundus than tapetal fundus. Serum vitamin A concentration was as low as 4.1 ,$\mu\textrm{g}$/dl in the calves of the affected farms. Narrowing of optic foramen, retinal degeneration and optic disc atrophy were shown in pathological findings.

• Korean Journal of Veterinary Research
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• v.58 no.4
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• pp.219-221
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• 2018

A 2-year-old intact female Bengal cat was presented with a 6-month history of visual impairment. The cat manifested bilateral negative menace responses and dazzle reflexes and sluggish pupillary light reflexes. Bilateral fundus changes included generalized tapetal hyperreflectivity, advanced retinal vascular attenuation, and increased pallor of the optic disc. A diagnosis of bilateral retinal degeneration was made. The clinical findings suggest that the investigated Bengal cat was most likely to have an inherited retinal degeneration. Further studies of the Bengal cat breed are needed to determine the prevalence of inherited retinal degeneration in this breed in Korea.

• Korean Journal of Ophthalmology
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• v.32 no.6
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• pp.470-477
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• 2018

Purpose: To investigate the relationship between the progression of visual field (VF) loss and changes in lamina cribrosa depth (LCD) as determined by spectral-domain optical coherence tomography (SD-OCT) enhanced depth imaging in patients with primary open angle glaucoma (POAG). Methods: Data from 60 POAG patients (mean follow-up, $3.5{\pm}0.7$ years) were included in this retrospective study. The LCD was measured in the optic disc image using SD-OCT enhanced depth imaging scanning at each visit. Change in the LCD was considered to either 'increase' or 'decrease' when the differences between baseline and the latest two consecutive follow-up visits were greater than the corresponding reproducibility coefficient value ($23.08{\mu}m$, as determined in a preliminary reproducibility study). All participants were divided into three groups: increased LCD (ILCD), decreased LCD (DLCD), and no LCD change (NLCD). The Early Manifest Glaucoma Trial criteria were used to define VF deterioration. Kaplan-Meier survival analysis and Cox's proportional hazard models were performed to explore the relationship between VF progression and LCD change. Results: Of the 60 eyes examined, 35.0% (21 eyes), 28.3% (17 eyes), and 36.7% (22 eyes) were classified as the ILCD, DLCD, and NLCD groups, respectively. Kaplan-Meier survival analysis showed a greater cumulative probability of VF progression in the ILCD group than in the NLCD (p < 0.001) or DLCD groups (p = 0.018). Increased LCD was identified as the only risk factor for VF progression in the Cox proportional hazard models (hazard ratio, 1.008; 95% confidence interval, 1.000 to 1.015; p = 0.047). Conclusions: Increased LCD was associated with a greater possibility of VF progression. The quantitative measurement of LCD changes, determined by SD-OCT, is a potential biomarker for the prediction of VF deterioration in patients with POAG.

• Journal of Veterinary Clinics
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• v.32 no.1
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• pp.123-126
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• 2015

A 14-year-old, male Shih-tzu was presented with glaucoma in the left eye. Menace response was negative in the left eye. On ophthalmic examination, exotropia, buphthalmos, bulging of upper lateral globe and episcleral injection was detected in the left eye. Also, there was corneal edema, corneal pigmentation and hyphema in the left eye. The pupil was difficult to observe due to corneal lesions in the left eye. On ultrasonographic examination, an amorphous large mass protruding from the region of the optic disc into the vitreous was observed in the left eye. Enucleation was performed in the left eye. Histologically, the left intraocular mass was diagnosed as glioma. Immunohistochemically, the neoplastic cells were positive to glial fibrillary acidic protein.

• Korean Journal of Veterinary Research
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• v.41 no.1
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• pp.113-121
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• 2001

Beagle is one of the most popular laboratory animal in a dog. We investigated the incidence of spontaneous ophthalmic disease in Beagles in order to make basic data for quality control of Beagles in Korea. We surveyed 389 beagles from 3 different farms. The average prevalence rate of ophthalmic diseases was 19.3%. The prevalence rate of cataracts was higher than any other ophthalmic diseases, 7.5% and then in order of corneal scar(2.1%), retinal hemorrhage(1.5%), post-inflammatory retinal change(1.5%), cherry eye(1.0%), distichiasis(0.8%), entropion(0.8%), hypoplastic optic disc(0.8%), conjunctivitis(0.5%), retinal dysplasia(0.5%), asteroid hyalosis(0.3%), congenital eye anomaly(0.3%), corneal lipidosis(0.3%), conjunctival hemorrhage(0.3%), lens capsule pigmentation(0.3%), persistent hyperplastic primary vitreous (0.3%), posterior synechia(0.3%), eyelid tumor(0.3%) and uveal cyst(0.3%) were diagnosed. There was a slight difference between male(24.8%) and female(17.4%) in prevalence rate of ophthalmic disease. The incidence of spontaneous ophthalmic disease was increased with age. These data would be useful for using Beagles as laboratory animals and standard reference for quality control of dogs.

• The Journal of Korean Institute of Information Technology
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• v.17 no.5
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• pp.77-82
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• 2019

Diabetic retinopathy is a complicated form of diabetes due to circulatory disorder in the peripheral blood vessels of the retina. We segment the microvessel for diagnosing diabetic retinophathy. The conventional methods using filter and features can segment the thick blood vessels, but it has relatively weak for segmenting fine blood vessels. In pre-processing step, noise reduction filter and histogram equalization are applied to suppress the noise and enhance the image contrast. Then, deep learning technique is used for pixel-by-pixel segmentation. The accuracy of conventional methods is between 90% to 94%, while the proposed method has improved as 95% accuracy. There is a problem of segmentation error around the optic disc and exudate due to the network depth. However the accuracy can be improved by modifying the network architecture in the future.

• Journal of Korea Game Society
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• v.12 no.1
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• pp.103-111
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• 2012

Games in 1970s have used the savings of analog wavelength as in music and the like on hardwares of small cassette, gramophone, and the like. Due to these configuration elements, durability has to be declined so much. In the event of using the music on the video game, more affordable method is to use the computer chip to convert the analog sound into the computer code to convert into the electric wavelength to send to the speaker. The sound effect of the game is generated in this method. The technical limit has been gradually overcome to grant more freedom to the composers and the sound track pre-recorded on the optic disc and the like has emerged. The game developers of today have made several attempts on the technology to produce the game music. This study has contemplated the process of advancement in the change of game music production with the influence on technology and business.