• Journal of the Korea Convergence Society
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• v.4 no.2
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• pp.21-27
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• 2013

Spot welding is automation of assembly process, without increasing the vehicle weight and economy, there is a fuel economy improvement of motor vehicles and to widely used in the automotive industry. But By irregular load from the road surface while at the vehicle is running, stress concentration occurs in the weld point, fatigue failure occurs frequently. Considering change of stiffness is the essential fatigue life of the evaluation spot weld. In this paper, by performing a linear static analysis was to understand the vulnerable part. Acquire to the fatigue properties of the spot weld, take the load history of the three levels in the time domain, was performed by setting as a condition of quasi-static fatigue analysis. and Fatigue life prediction method of the spot weld was by applying the method according to the fatigue damage accumulation and the conventional method was compared analyzed with the results shown.

• Archives of Reconstructive Microsurgery
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• v.9 no.2
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• pp.172-178
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• 2000

With esthetic concern in the reconstruction of skin and soft tissue defects of face, the use of local flap has been the method of choice. However, when there is extensive tissue loss in the face, local flaps do not provide satisfactory results. The amazing development of microsurgical technique has decreased the percentage of free flap failure, thus making free flap use in reconstruction of facial soft tissue defects. Many free flaps has been applied for reconstruction of face defects. Especially, the radial forearm flap has numerous advantages with which facial reconstruction is made possible. But, its disadvantages are ; the sacrifice of one major artery supplying the hand and donor site complications. In order to circumvent these disadvantages, we employed posterior interosseous artery(PIA) forearm free flap for the reconstruction of the face defects. The posterior interosseous forearm island flap was first described by Zancolli and Angrigiani(1985). Currently, the PIA island flap and free flap have been used for hand reconstructions. The disadvantages of the PIA flap are ; the small caliber of the pedicle, different locations of the perforating branches, and the proximity of the motor branch of the radial nerve. But, its advantages lies in preserving the major artery of the hand, minimal donor site morbidity, and fairly well matched skin texture and color, and that the flap volume is sufficient, not too bulky with convenient handling. By using this flap, we performed 1 case of tumor resection and 1 case of traumatic defect. From our experiences we conclude that it is one of many useful methods in the reconstruction of the skin and soft tissue defects of the face. We also have discussed advantages and some limitations of various free flaps for reconstruction of the face.

• Journal of Korean Neurosurgical Society
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• v.46 no.6
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• pp.538-544
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• 2009

Objective : Primary treatment of spinal metastasis has been external beam radiotherapy. Recent advance of technology enables radiosurgery to be extended to extracranial lesions. The purpose of this study was to determine the clinical effectiveness and safety of stereotactic radiosurgery using Cyberknife in spinal metastasis. Methods : From June, 2002 to December, 2007, 129 patients with 167 spinal metastases were treated with Cyberknife. Most of the patients (94%) presented with pain and nine patients suffered from motor deficits. Twelve patients were asymptomatic. Fifty-three patients (32%) had previous radiation therapy. Using Cyberknife, 16-39 Gy in 1-5 fractions were delivered to spinal metastatic lesions. Radiation dose was not different regarding the tumor pathology or tumor volume. Results : After six months follow-up, patient evaluation was possible in 108 lesions. Among them, significant pain relief was seen in 98 lesions (91%). Radiological data were obtained in 83 lesions. The mass size was decreased or stable in 75 lesions and increased in eight lesions. Radiological control failure cases were hepatocellular carcinoma (5 cases), lung cancer (1 case), breast cancer (1 case) and renal cell carcinoma (1 case). Treatment-related radiation injury was not detected. Conclusion : Cyberknife radiosurgery is clinically effective and safe for spinal metastases. It is true even in previously irradiated patients. Compared to conventional radiation therapy, Cyberknife shows higher pain control rate and its treatment process is more convenient for patients. Thus, it can be regarded as a primary treatment modality for spinal metastases.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.9
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• pp.691-701
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• 2020

An actuator mixer design using convex optimization technique situation where the propulsion system of an electric VTOL UAV during vertical take-off and landing maneuvers is proposed. The attainable control set to analyze the impact from failure of each motor and propeller can be calculated and illustrated using the properties of the convex function. The control allocation can be defined as a convex function optimization problem to obtain an optimal solution in real time. The mixer is implemented using a convex optimization solver, and the performance of the control allocation methods is compared to the attainable control set. Finally, the proposed mixer is compared with other techniques with nonlinear sux degree-of-freedom simulation.

• Journal of Korean Neurosurgical Society
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• v.41 no.1
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• pp.22-26
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• 2007

Objective : Cerebral palsy may induce harmful spastic hip adduction. We report the result of microsurgical selective obturator neurotomy, performed on 12 spastic hip adductions of 6 patients, followed clinically for at least 26 months postoperatively. Methods : Microsurgical selective obturator neurotomies, involving microsurgical resection of the anterior obturator nerve branches were performed on 6 patients from January 2000 through June 2003. All patients presented with the inability to sit and 2 patients complained of persistent, intractable pain. We used intraoperative bipolar stimulation to identify selected motor branches. Results : The procedure was performed bilaterally in all patients. In the 3 patients in whom contractures were present, microsurgical selective obturator neurotomies were accompanied by an additional tenotomy of the adductor muscles. Selective tibial neurotomy was performed on three of six patients who originally presented with a spastic ankle. Postoperatively, all spastic hip adductions were corrected more than 60 degrees in passive abduction-adduction amplitude. However, one patient who did not receive active postoperative physiotherapy demonstrated a decreased passive abduction-adduction amplitude upon follow-up. There were no surgical complications. Conclusion : We think microsurgical selective obturator neurotomy may be an effective procedure in the treatment of localized, harmful spastic hip adduction after failure of well conducted conservative treatment. As muscular contractions are often associated with spasticity of the hip adductors, an adjunctive tenotomy may be an option. Comprehensive postoperative physiotherapy is essential to improve long-term results.

• Journal of Korean Neurosurgical Society
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• v.43 no.4
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• pp.186-189
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• 2008

Objective : We assessed the surgical results of percutaneous balloon compression in 50 patients with idiopathic trigeminal neuralgia. Methods : Fifty patients with follow-up period of more than 12 months were retrospectively analyzed. The mean follow-up period was 42 months (range, 12-82). The mean age was 65.8 years (range, 27-83). Seventeen patients (34%) had other previous surgical procedures. The balloon was inflated by injecting radio-contrast media under brief general anesthesia according to Mullan’s technique. The mean inflating time was 88 seconds (range, 60-120). The whole procedure took about 20 minutes. Results : We reported excellent and good results in 70% of the cases, poor in 6% as annoying dysesthesia, recurrence in 16%, and 8% failure due to technical deficiencies. Forty-six patients (92%) were initially relieved of their pain. There were permanent motor weakness of the masseter muscle in 4% of patients and transitory diplopia in 8%. Neither anesthesia dolorosa nor keratitis occurred. Almost all patients (92%) were discharged postoperatively within two days. Conclusion : These results indicate that balloon compression would be an effective method with acceptable morbidity, technically, It can be performed rapidly and simply in the treatment of idiopathic trigeminal neuralgia.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.11
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• pp.2128-2132
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• 2017

Smart mobility is rapidly emerging as a next-generation eco-friendly transportation system, and the market is booming every year. However, due to the characteristics of the devices that use electricity as the power source, the motor and the battery are different from the performance and actual performance indicated by the manufacturer depending on the user's weight and driving environment. Therefore, The frequency of the overload is increased and the failure and damage of the device are increasing. In this paper, we propose an application that provides personalized recommended driving guidance and overloaded driving situation notification at the actual driving separately from the recommended driving provided by the manufacturer after measuring the driving environment of the user, so as to prevent malfunction and damage of the smart mobility device, To ensure safety.

• Journal of The Korean Society of Clinical Toxicology
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• v.4 no.2
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• pp.161-165
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• 2006

Organophosphate insecticides, commonly used in agriculture, are a gradually increasing cause of accidental and suicidal poisoning. Intoxication can occur by ingestion, inhalation or dermal contact. Exposure to organophosphorus agents causes a sequentially triphasic illness consisting of the cholinergic phase, the intermediate syndrome, and organophosphate-induced delayed polyneuropathy. Acute pancreatitis as a rare complication of organophosphate intoxication has also been infrequently observed. We report a case of intoxication with organophosphate (phos-phamidon) by parenteral exposure (inhalation and/or dermal contact). A 34-year-old male patient was transferred to our Emergency Medical Center and was intubated due to a progressive respiratory failure. He presented with meiotic pupils, cranial nerve palsies, weak respiration, and proximal limb motor weaknesses without sensory changes. He had been employed in filling syringes with phosphamidon during the previous month. Because the patient's history and symptoms suggested organophosphate intoxication with intermediate syndrome, he was mechanically ventilated for 18 days with continuous infusion of atropine and pralidoxime (total amounts of 159 mg and 216 g, respectively). During his admission, hyperamylasemia and hyperli-pasemia were detected, and his abdominal CT scan showed a finding compatible with acute pancreatitis. He was administered a conservative treatment with NPO and nasogastric drainage. The patient was discharged and showed neither gastrointestinal nor neurologic sequelae upon follow up at one week and three months.

• Journal of Chest Surgery
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• v.28 no.6
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• pp.533-541
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• 1995

We recently developed a new model of moving actuator type totally implantable artificial heart[TIAH , based on the reverse position of the aortic and pulmonary conduits. This concept was proposed by one of surgeons in our team[Joon-Ryang Rho, M.D. to facilitate anatomical fitting of TIAHs. The moving actuator type electromechanical TIAH consisted of the left and right blood sacs, and the moving actuator including a motor. The inverted umbrella type polyurethane valves were used in the blood pumps. The aortic conduit was positioned anterior to the pulmonary conduit, which was the opposite relation to the conventional configuration of other total artificial hearts. We also adapted slip-in connectors for the aortic and pulmonary conduits. Two sheep , weighing 60-69 kg, were used for implantation. After small cervical incision and trans-sternal bilateral thoracotomy, cardiopulmonary bypass [CPB was administered using an American Optical 5-head pump and a membrane oxygenator[Univox-IC, Bentley . The anterior and posterior vena cavae were drained separately for venous return. An arterial return cannula was inserted into the right common carotid artery. During CPB, almost all of the ventricular myocardium was excised down to the atrioventricular groove and the artificial heart was implanted. We achieved 3-day survival in the first sheep and 2-day survival in the second. The day after operation the first sheep was successfully extubated and the second sheep was weaned from a respirator with good condition. After extubation, the first sheep walked around in the cage and fed herself. Serial laboratory and hemodynamic examinations were done during the experiments. In both sheep, pulmonary dysfunction was gradually developed, which was accompanied by acute renal failure. The animals were sacrificed and autopsy was done. Unexpected pregnnacy was incidentally found in both sheep. To our knowledge this is the first report of significant survival cases in the orthotopic implantation of electric TIAH using sheep.

• The Journal of Korean Physical Therapy
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• v.15 no.4
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• pp.199-207
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• 2003

This review describes the neurophathological mechanisms that are implicated in perinatal brain injury. Perinatal brain injury is the most important cause of morbidity and mortality to infants, often leading to spastic motor deficits, mental retardation, seizures, and learning impairments. The immature brain injury is usually caused by cerebral hypoxia-ischemia, hemorrhage, or infection. The important form of perinatal brain injury is the hypoxic-ischemic injury and the cerebral hemorrhage. The pathology of hypoxic-ischemic injury include delayed energy failure by mitochondrial dysfunction, neuronal excitotoxicity and vulnerability of white matter in developing brain. The immature brain has the fragile vascular bed of germinal matrix and can not effectively centralize their circulation. Therefore, the cerebral hemorrhage process is considered to be involved in the periventricular leukomalacia.