• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.11
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• pp.979-986
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• 2016

The tripod shafts of constant-velocity joint are used in both the trains KTX and KTX-sanchon. It is an important component that connects the motor reduction unit and the axle reduction unit in a power bogie. The tripod shaft not only transmits drive and brake torque in the rotational direction, but also slides in the axial direction. If the drive system is loaded with an excessive torque, the fuse part of the shaft will be fractured firstly to protect the other important components. In this study, a rig was developed for conducting torsion tests on the tripod shaft, which is a type of mechanical fuse. The tripod shafts were subjected to torsional fracture test and torsional fatigue test on the rig. The weak zone of the tripod shaft was identified, and its fatigue life was predicted using finite element analysis (FEA). After analyzing the FEA results, design solutions were proposed to improve the strength and fatigue life of the tripod shaft. Furthermore, the deterioration trend and time for failure of the tripod shaft were verified using the hysteresis loops which had been changed with the advancement of the torsional fatigue test.

• Journal of Korean Neurosurgical Society
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• v.44 no.1
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• pp.26-35
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• 2008

Objective : In the evaluation of patients with Parkinson's disease (PD), most neurologists only see their patients during a limited period of their fluctuating 24-hour-a-day lives. This study aimed to assess the short-term outcome of STN stimulation for patients with advanced PD evaluated in a 24-hour monitoring unit for movement disorder (MUMD) using a prospective protocol. Methods : Forty-two patients with advanced PD consecutively treated with bilateral STN stimulation using multi-channel microelectrode recording were included in this study. All patients were evaluated using a 24-hour MUMD with a video recording/editing system and were evaluated with a prospective protocol of the Unified Parkinson's Disease Rating Scale, Hoehn and Yahr Staging, Schwab and England Activities of Daily Living, levodopa equivalent daily dose (LEDD), Short Form-36 Health Survey, and neuropsychological tests. Magnetic resonance (MR) images of the brain were performed prior to and six months after surgery. Results : All patients were evaluated at three and six months after surgery. There was a rapid and significant improvement of the motor symptoms, especially in tremor and rigidity, after STN stimulation with low morbidity. Dyskinesia was markedly decreased with much lowered LEDD values by 50% after STN stimulation. 1.5T MR images were safely taken according to the manufacturer's guidelines at six months after surgery without any adverse effects in 41 patients treated with STN stimulations. Conclusion : Evaluations in a 24-hour monitoring unit could reduce the dose of medication efficiently to an optimal level with patients' comfort and improve the clinical symptoms in harmony with STN stimulation.

• Journal of Acupuncture Research
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• v.20 no.3
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• pp.194-208
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• 2003

Objective : Recently, many studies have showed the evidences of the effect of acupuncture treatment through scientific methods. We performed electro-acupuncture on Taixi(K3) and observed the change of brain activity using fMRI. Methods : To see the effect of electro-acupuncture stimulation on Taixi(K3), the experiment was carried out on twelve healthy volunteers, using the gradient echo sequence with the 3.0T whole-body fMRI system(ISOL). After the needle insertion on K3, 2 Hz of electric stimulation was given for 30 seconds, repeated five times, with 30 seconds' intervals. Result & Conclusions : Unilateral electro-acupuncture stimulation on K3 increased the brain activity in Brodman Area 8, 6, 9, 13, 21, 22, 38, 40, 43, 2, 5, 10, 20, 24, 32, 34, 37, 39, 41, 42. and decreased the brain activity in Brodman Area 9, 13, 38, 22, 31, 3, 6, 10, 21, 25, 29, 30. Group Averaged Brain activity induced by Unilateral Electro-acupuncture Stimulation on K3 was increased in Brodman Area 10, 22, 42, 43, 44 and was decreased inn Brodman Area 6 and pyrogen test of Bee venom. Bilateral electro-acupuncture stimulation on k3 increased the brain activity in Brodman Area 22, 3, 19, 4, 13, 17, 21, 41, 42, 2, 5, 6, 7, 18, 23, 29, 30, 31, 40 and decreased the brain activity in Brodman Area 18, 6, 39, 4, 13, 2, 10, 19, 36, 40, 45, 46, 47. Group Averaged Brain activity induced by Bilateral Electro-acupuncture Stimulation on K3 was increased in Brodman Area 22, 13, 4, 3, 29, 38, 43 and was decreased in Brodman Area 18, 3, 19, 22, 39. Motor Stimulation activated Brodmann Area 6, 43, 18.

• The Korean Journal of Pain
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• v.7 no.2
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• pp.162-169
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• 1994

Blockade of cervicothoracic sympathetic ganglion (stellate ganglion controls pain on face, head, neck, shoulder, upper limbs, and upper chest, including their viscera and sympathetically maintained pain. This procedure also increases blood flow to the above areas and relieves hyperreactivity of sympathetic nervous system. Clinically, repeated stellate ganglion blocks with local anesthetic agent may become difficult with complications such as accidental intravascular or subdural injection, recurrent laryngeal nerve or bracheal plexus paralysis, pneumothorax and edema on injection site. Therefore, at times long-term cervicothoracic ganglion block with neurolytics is necessitated but its applications are prohibited by the critical structures surrounding ganglion. There are also few reports of neurolytic stellate ganglion block. This study was performed to observe the complications, gross changes of surrounding structures, and microscopic findings of ganglion cells after neurolytic block and to certify the possibility of clinical use of neruolytic stellate ganglion block. The unilateral superior cervical sympathetic ganglion of rabbit was blocked with absolute ethyl alcohol 0.4 ml at the level of cricoid cartilage. Normal ganglion was used as a control and 5 animals were sacrificed at each intervals of 7, 15 and 50 days after block. The results were as follows; 1) All experimental animals showed no specific changes of behavior, motor function. No necrotic tissues were present in the block area during the observation period. There were some gross scar tissues along the fascia of muscles surrounding the needle injection site, but gross atrophy of muscles or injured major vessels were not found. 2) Microscopically, structures of normal ganglion of rabbit were very similar to those of humans. Seven days after absolute ethyl achohol injection there were marked edema of ganglion cells and nuclei with irregular nuclear membrane. Some of the ganglion cells lost their nuclei and showed degenerative changes. Fifteen days after block, cell edema were decreased and loss of the Nissl's body was prominant. The ganglion cell structures looked close to normal but the cytoplasm and nucleus were generally contracted 50 days after block. These results suggest absolute ethyl alcohol injection on cervical sympathetic ganglion with above method mainly blocks pre- and post-synaptic fibers and the long-term neurolytic blockade of this ganglion may be possible in rabbits.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11b
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• pp.472-479
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• 2000

A persimmon harvesting vehicle that can be operated in hilly orchards as well as a manipulator that can be used to harvest persimmons located in remote positions in the trees were designed and developed. The vehicle could be operated with keeping balanced position in an inclined field and its working platform could be moved up and down easy to approach fruits in a remote region with the aids of a hydraulic and a electrical and electronics systems. The weight of the vehicle was 927 kg and the center of gravity was located at 427 mm to the inner side from the center of a right driving caterpillar, 607 mm to a rear axle from the center of a front axle, and 562 mm to upward from ground. The automatic level control sensor for leveling the working platform was activated within 14.5 ∼ 16.5 degrees of slope variation. The total length of the manipulator was 1.39 m and weight is 975 g. It was powered by a 12 V geared motor to detach persimmon fruits with a rotational force. The gripper was made of plastic and rubber to increase a frictional force. In a performance evaluation test, static tipping angle, dynamic tipping angle toward front side when the vehicle was moving downward, climbing angle, driving speed of the vehicle were measured or calculated. In persimmon harvesting tests 24.9% of yield was increased by hand picking with the aid of the vehicle and additional 7% of yield were increased when the manipulator was used. Therefore, 99010 of total possible yield was achievable when both of the vehicle and the manipulator were used for the manual persimmon harvesting. Increase in 22.5% of total yield was achieved with the manipulator only.

• Clinical and Experimental Pediatrics
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• v.51 no.12
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• pp.1324-1328
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• 2008

Purpose : Attention deficit hyperactivity disorder (ADHD) is a syndrome characterized by inattention, impulsive disruptive behavior, impaired concentration, and motor restlessness. This study examined the relationships among electroencephalographic (EEG) findings, stimulant use, and seizure occurrence in children with ADHD. Methods : We retrospectively studied 308 children with ADHD who visited the neuropsychiatric clinic of our hospital from January 2001 to December 2005. We retrospectively analyzed age distribution, etiology, abnormal EEG findings, and use of CNS stimulants. Among these children, brain waves was recorded in 84 patients. Results : Eighty-four children (72 males, 85.7%, 9.3 years mean age; 12 females, 14.3%, 8.0 years mean age) with ADHD had electroencephalograms (EEGs) performed at our institute. Nineteen patients (22.6%) demonstrated epileptiform abnormalities, and 65 (77.4%) demonstrated normal EEGs. Stimulant therapy was applied to 59 of 84 patients (70.2%). Seizures occurred in 1 of 65 patients with a normal EEG (incidence, 1.5%) and 3 of 19 treated patients with epileptiform EEGs (incidence, 15.7%). Conclusion : These data suggest that patients with normal EEGs have minor risk for seizure. In contrast, patients with epileptiform EEGs have higher risk for seizure than patients with normal EEGs.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.12 no.1
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• pp.49-53
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• 2012

X-linked adrenoleukodystrophy (ALD) is a rare inherited metabolic disease which results in impaired peroxisomal ${\beta}$-oxidation and the accumulation of very long chain fatty acids (VLCFA) in the adrenal cortex, the myelin of the central nervous system, and the testes. X-linked ALD is caused by mutations in the ABCD1 gene encoding an ATP-binding cassette transporter superfamily located in the peroxisomal membrane. This disease is characterized by a variety of phenotypes. The classic childhood cerebral ALD is a rapidly progressive demyelinating condition affecting the cerebral white matter before the age of 10 years in boys. We report the case of a 8-year-old with childhood cerebral X-linked ALD who developed inattention, hyperactivity, motor incoordination and hemiparesis. We diagnosed ALD with elevated plasma very long chain fatty acid level and diffuse high signal intensity lesions in both parieto-occipital white matter and cerebellar white matter in brain MRI. We identified a novel c.983delT (p.Met329CysfsX7) mutation of the ABCD1 gene. There is no correlation between X-ALD phenotype and mutations in the ABCD1 gene. Further studies for searching additional non-genetic factor which determine the phenotypic variation will be needed.

• Therapeutic Science for Rehabilitation
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• v.6 no.1
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• pp.55-69
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• 2017

Objective : The purpose of this study was to investigate the reliability and concurrent validity of the computerized cognitive function test system (called CNFT) for evaluating the cognitive function and to provide its normative data. Methods : For this purpose, 140 normal adults participated in a investigation to provide the normative data of CNFT. 40 normal adults participated in an evaluating experiment to verify the reliability and validity. CNFT consists of attention, memory, sensori-motor coordination, and frontal lobe & higher cognitive function domains. Because CNFT is a computerized evaluation tool, all results and operations are processed consistently and automatically. Results : In the results, as the age of subjects increased, the average accuracy decreased and response time increased. Additionally, memory and frontal lobe & higher cognitive function was lower than other domains. Test-retest reliability of 2 weeks interval was highly correlated (r=.48~.85) and there is no significant difference between test and retest scores. CNFT was highly correlated with computerized neurocognitive function test (r=.67~.79; p<.05). Conclusion : Normative data of CNFT were obtained, and the guidelines for the interpretation were provided. A reliable and valid clinically applicable computerized cognitive function test was developed.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.29 no.4
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• pp.464-476
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• 2019

Objectives: This study aimed to assess the exposure levels of tollbooth workers to diesel particulate matter using black carbon (BC) and to find the correlations among variables associated with BC using the motor vehicle management act regulated by the Ministry of Land, Infrastructure and Transport. Methods: This study was performed over 14 days at a university in Seoul. BC levels were monitored using an aethalometer and were conducted around the breathing zones of the workers. There were three sampling locations: inside the tollbooth (front gate and rear gate) and an office as a control group. T-test, correlation, and multiple linear regression analysis were performed using SPSS. Results: The geometric mean (GM) of BC_30min concentrations in the exposure group was 2.44 ㎍/㎥, approximately 1.4 times higher than the control group (1.75 ㎍/㎥). The GM of BC_30min concentrations was 2.75 ㎍/㎥ during the heavy traffic time (9-10 am) and 2.30 ㎍/㎥ during non-heavy traffic times (p<0.001). The multiple linear regression analysis shows that the number of all types of vehicles and PM_2.5 concentrations in the atmosphere were factors increasing the GM of BC(ln(BC_30min)) concentrations (adjusted R²=0.42, p<0.001). The workers were constantly exposed to low concentrations (GM of BC_30min=2.44 ㎍/㎥), but they were exposed to peak concentrations instantly (BC_10sec=3545.04 ㎍/㎥). When the GM of BC_30min concentrations was momentarily represented as high, it was identified that a vehicle mainly using diesel fuel or an aging vehicle had passed. Conclusions: A ventilation system should be installed in the closed tollbooth or aging vehicles should be controlled so as not to pass tollbooths.

• Publications of The Korean Astronomical Society
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• v.24 no.1
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• pp.53-64
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• 2009

MIRIS is the main payload of the STSAT-3 (Science and Technology Satellite 3) and the first infrared space telescope for astronomical observation in Korea. MIRIS space observation camera (SOC) covers the observation wavelength from $0.9{\mu}m$ to $2.0{\mu}m$ with a wide field of view $3.67^{\circ}\times3.67^{\circ}$. The PICNIC HgCdTe detector in a cold box is cooled down below 100K by a micro Stirling cooler of which cooling capacity is 220mW at 77K. MIRIS SOC adopts passive cooling technique to chill the telescope below 200 K by pointing to the deep space (3K). The cooling mechanism employs a radiator, a Winston cone baffle, a thermal shield, MLI (Multi Layer Insulation) of 30 layers, and GFRP (Glass Fiber Reinforced Plastic) pipe support in the system. Optomechanical analysis was made in order to estimate and compensate possible stresses from the thermal contraction of mounting parts at cryogenic temperatures. Finite Element Analysis (FEA) of mechanical structure was also conducted to ensure safety and stability in launching environments and in orbit. MIRIS SOC will mainly perform Galactic plane survey with narrow band filters (Pa $\alpha$ and Pa $\alpha$ continuum) and CIB (Cosmic Infrared Background) observation with wide band filters (I and H) driven by a cryogenic stepping motor.