• Korean Journal of Optics and Photonics
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• v.9 no.2
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• pp.51-58
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• 1998

We investigated surface-relief profiles of the TPHK(telecentric paraxial holographic kinofrm) used as a Fourier-transform lens employing exact geometrical raytracing. For the TPHK of F/8 and focal length of 15 mm, we consider the cases where the thickness of the substrate is 0 and 50 ${\mu}{\textrm}{m}$, dividing the surface-relif profiles into fifty steps from plano-convex to convexplano shapes and varying the angle of incidence($0^{\circ},{2.5}^{\circ},5^{\circ}$). In order to identify appropriate surface-relief profiles, we employ, as criteria of performance, rms spot size, rms deviation from $f{\sin}{\theta}$, peak position and FWHM(full width at half maximum), number of rays abandoned from raytracing etc., which are determined from the result of exact raytracing. It is found that the profile with 80% of its relief thickness facing the image plane gives the best performance regardless of the presence of substrate.

• Journal of Korean Neurosurgical Society
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• v.47 no.4
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• pp.271-277
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• 2010

Objective : The purpose of this study is to evaluate the clinical characteristics and surgical outcome of cerebellopontine angle (CPA) epidermoids presenting with trigeminal neuralgia. Methods : Between 1996 and 2004, 10 patients with typical symptoms of trigeminal neuralgia were found to have cerebellopontine angle epidermoids and treated surgically at our hospital. We retrospectively analyzed the clinico-radiological records of the patients. Results : Total resection was done in 6 patients (60%). Surgical removal of tumor and microvascular decompression of the trigeminal nerve were performed simultaneously in one case. One patient died due to postoperative aseptic meningitis. The others showed total relief from pain. During follow-up, no patients experienced recurrence of their trigeminal neuralgia (TN). Conclusion : The clinical features of TN from CPA epidermoids are characterized by symptom onset at a younger age compared to TN from vascular causes. In addition to removal of the tumor, the possibility of vascular compression at the root entry zone of the trigeminal nerve should be kept in mind. If it exists, a microvascular decompression (MVD) should be performed. Recurrence of tumor is rare in both total and subtotal removal cases, but long-term follow-up is required.

• Journal of Korean Foot and Ankle Society
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• v.7 no.2
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• pp.179-186
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• 2003

Purpose: The purpose of this study was to evaluate the result of modified Lapidusprocedure for Hallux valgus associated with first ray hypermobility Materials and Methods: A retrospective study was conducted between Aug. 1999 and Oct. 2003. We evaluated 20 cases (12patients)of hallux valgus that performed modified Lapidus procedure. We asked to patient about postoperative satisfaction in terms of overall, pain, and appearance. preoperative and postoperative AOFAS score for the forefoot was calculated, also preoperative and postoperative radiologic evaluation was done. Results: In terms of satifaction, overall rate was 70%, pain relief and appearance were 70% and 70%. preoperative mean Hallux valgus angle and mean intermetatarsal angle were 42.6degree and 19.4degree. after procedure, at last follow up, mean hallux valgus angle and mean intermetatarsal angle were 16degree and 8.7degree. In terms of complication, nonunion was seen in 3 cases and recurrence of hallux valgus deformity was 2 cases. Conclusion: In consideration of high complication rate, modified Lapidus prociduremust be improved in terms of more rigid fixation technique, etc.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.4
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• pp.279-285
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• 2016

In this paper, a platform design of caterpillar typed electrical vehicle is proposed. Nowadays, there have been many researches on mobile robots in the various ways. Many different fields such as military, exploration, agricultural assistance and disaster relief have applied the mobile robot. Design condition of stable angle, upset angle is reflect to caterpillar typed electrical vehicle. To experiment, developed a caterpillar typed electrical vehicle and design a driving controller. Developed caterpillar typed electrical vehicle is tested about operating and driving. Test environment is consisted of driving on flatland and climbing 15 degree and outdoor 40 degree slope. It is confirmed that developed tracked electric vehicular robot can driving and climbing.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.122-125
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• 1993

The various geometry of tap been developed in order to tap special workmaterial at considerably higher cutting speed than that of the conventional HSS tap. In this paper a piezo type tool dynamomerer is constructed and used to measure the torque. The experimental tests are run with various cutting speed. It is clarified that the process of chip formation strongly depends on rake angle, relief angel, angel of twist.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.3
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• pp.50-55
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• 2008

In this paper, we propose a new shape compensation scheme to make up for the difference in groove radius between the formed tools and the machined bearing raceways, which inherently takes place during machining the ball bearing raceways by the turning process using conventional formed tools. The associated conventional methods of the formed tool design and its modification such as a simple depth compensation method and a graphical compensation method are introduced and the latter, which has been known to be the better of the two, is experimentally investigated in detail to reveal its drawback. The algorithm is given and it is applied to develop a formed tool design program. The program developed by the presented approach is successfully applied to design the formed turning tool for the bearing raceways.

• The korean journal of orthodontics
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• v.21 no.3
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• pp.711-722
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• 1991

The first patient of this case was 13 year and 8 month old girl who had the Angle's class I malocclusion with uneruption of upper left central incisor and left canine. The second patient was 12 year old boy who had the Angle's class I malocclusion with uneruption of right central incisor. After surgical exposure of impacted teeth of those patients and bonding of attachment on exposed crown, those teeth were orthodontically pulled with removable appliances. The results were obtained as follow. 1. The functionally proper occlusion was established by guidance of the impacted teeth into the normal position in the arch. 2. Establishment of esthetic and balanced arch form was achieved. 3. The possibility of restorative prosthetic treatment induced by extraction of impacted teeth was eliminated. 4. The psychologic relief of pubertal patient who was very sensitive to facial esthetics was gained.

• ETRI Journal
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• v.45 no.5
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• pp.746-757
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• 2023

This study presents a novel safe landing algorithm for urban drone deliveries. The rapid advancement of drone technology has given rise to various delivery services for everyday necessities and emergency relief efforts. However, the reliability of drone delivery technology is still insufficient for application in urban environments. The proposed approach uses the "landing angle control" method to allow the drone to land vertically and a rapidly exploring random tree-based collision avoidance algorithm to generate safe and efficient vertical landing paths for drones while avoiding common urban obstacles like trees, street lights, utility poles, and wires; these methods allow for precise and reliable urban drone delivery. We verified the approach within a Gazebo simulation operated through ROS using a six-degree-of-freedom drone model and sensors with similar specifications to actual models. The performance of the algorithms was tested in various scenarios by comparing it with that of stateof-the-art 3D path planning algorithms.

• Journal of Korean Foot and Ankle Society
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• v.11 no.2
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• pp.171-176
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• 2007

Purpose: We assess the mid to long term follow up results of arthrodesis of the first metatarso-phalangeal (MTP) joint and resection arthroplasty of the lesser toes in rheumatoid arthritic forefoot deformity. Materials and Methods: Between 1998 to 2001 year, 25 cases (18 patients) rheumatoid forefoot deformities were surgically corrected. Follow up period was 83 months (range, 63 to 90 months). The clinical outcome was evaluated using subjective satisfaction and AOFAS score. The radiological measurements were hallux valgus angle, first and second intermetatarsal angle, second metatarso-phalangeal angle (MTP-$2^{nd}$ angle). Results: Subjective satisfaction was 76%. AOFAS score improved from 37 to 73. The hallux valgus angle improved from preoperative $39^{\circ}$ ($27{\sim}64^{\circ}$) to $14^{\circ}$ ($4{\sim}34$) at the last follow up. The intermetatarsal angle were preoperative $13^{\circ}$ ($6{\sim}22^{\circ}$) to $11^{\circ}$ ($3{\sim}13^{\circ}$) at the last follow up, The MTP-$2^{nd}$ angle were preoperative $24^{\circ}$ ($9{\sim}47$) to last follow up $15^{\circ}$ ($2{\sim}39^{\circ}$) respectively (p>0.05). Complication was intractable callus 10 cases, Interphalangeal arthritis 5 cases. Conclusion: Mid to long term outcomes rheumatoid forefoot reconstruction by first MTP arthrodesis and resection arthroplasty of lesser toes results a satisfaction and pain relief.

• Journal of the Korea Society of Computer and Information
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• v.25 no.8
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• pp.145-150
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• 2020

Forward head posture is one of the most recognized types of poor head and neck alignment. Poor head and neck alignment posture is a major contributor to compromised balance and neck pain, due to abnormal joint position sense and proprioception. Kinesio taping is an intervention method used clinically for the management of pain. Kinesio taping may produce its effects through pain reduction, stimulation of blood circulation, induction of muscle relaxation which provides correction of joint position, and providing stability to the muscles and joints without limiting the range of motion. Many studies have proved that kinesio taping has positive effects on the reduction of pain and improves alignment, on the other hand, some studies have not found. Kinesio taping may provide immediate pain relief and improved alignment following the application, but there is insufficient evidence to support sustained relief beyond that time and they recommended future studies to examine the benefits of kinesio taping as this would have a greater value in clinical practice. Therefore, this study is to investigate the effects of kinesio taping on the alignment of head posture and dynamic balance ability in people with forward head posture.