• Journal of Korean Ophthalmic Optics Society
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• v.3 no.1
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• pp.189-199
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• 1998

The system for optical tolerances of completion spectacles was made to sum of the accumulated error - the circumstances on composing prescription, the visual-distance, the tilting angle, the losing of a temple, the vertex distance, the axis of toric lens and the sloping of lens etc. It was given by the relation of allowed values size(T) and power(D), $T=T_0e^{-aD}$. Here, $T_0$ is the size of allowed values of plane-lens with power is 0 and ${\alpha}$ is the factor of allowed values. In case of being adopted to new form s tolerance corresponding to RAL 915, for the tolerance is large direction, the factor of allowed values ${\alpha}$ is $0.166(T_0=5.90)$ and for the tolerance is small direction, the factor of allowed values ${\alpha}$ is $0.166(T_0=2.95)$.

• Science of Emotion and Sensibility
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• v.15 no.4
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• pp.469-476
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• 2012

The purpose of this study is to derive design guideline for logo design development of smart clothing using flexible plastic optical fiber. In a criterion of guideline derivation for logo design, the first, it is a question of whether it indicates an appropriate degree of brightness across the front of flexible plastic optical fiber. The second, it is a question of whether it indicates relatively an uniform brightness characteristic across the front of flexible plastic optical fiber. For this, the brightness characteristic of flexible plastic optical fiber according to the angle changes and the length of flexible plastic optical fiber was analyzed by the 'Experiment 1'. To deduce guideline for the logo design of the actual garment, the brightness characteristic of flexible plastic optical fiber about the main morpheme of the capital letter of alphabet was analyzed by the 'Experiment 2'. Based on the results of the two experiment, this study derived design guideline and limitations for logo design of smart clothing visualized by the flexible plastic optical fiber.

• Journal of Korean Neurosurgical Society
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• v.42 no.5
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• pp.363-366
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• 2007

Objective : Kyphoplasty performed in the middle thoracic spine presents technical challenges that differ from those in the lower thoracic or lumbar region due to small pedicle size and angular severity for thoracic kyphosis. The purpose of this study was to evaluate the efficacy of balloon kyphoplasty through extrapedicular approach for the treatment of intractable osteoporotic compression fractures in the middle thoracic spine. Methods : The patients who were performed with one level balloon kyphoplasty through extrapedicular approach due to painful osteoporotic compression fractures at T5-T8 from June 2003 to July 2005 were retrospectively analyzed. Imaging and clinical features were analyzed including involved vertebrae level, vertebral height, Injected cement volume, clinical outcome and complications. Results : Eighteen female patients (age ranged from 60 to 77 years old) were included in this study. The average amount of the implanted cement was $4.2{\pm}1.5\;cc$. The mean cobb angle and compression rate were improved from $12.1{\pm}6.5^{\circ}$ to $8.5{\pm}7.2^{\circ}$ and from 30% to 15%, respectively. The mean pain score (visual analogue scale) prior to kyphoplasty was 7.9 and it decreased to 3.0 after the procedure. Cement leakage to the adjacent disc (2 cases) and paravertebral soft tissues (1 case) were seen but there were no major complications such as pneumothorax, segmental arte 이 Injury, pulmonary embolism, or epidural leakage. Conclusion : Balloon kyphoplasty through extrapedicular approach is considered as a safe and effective in treating the middle thoracic regions with low complication rate.

• Journal of Korean Neurosurgical Society
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• v.41 no.4
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• pp.241-245
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• 2007

Objective : So called "minimally invasive procedures" have evolved from chemonucleolysis, automated percutaneous discectomy, arthroscopic microdiscectomy that are mainly working within the confines of intradiscal space to transforaminal endoscopic technique to remove herniated epidural disc materials directly. The purpose of this study is to assess the result of endoscopic spinal surgery and favorable indication in the thoracolumbar spine. Methods : The records of 71 patients, 73 endoscopic procedures, were retrospectively analysed. Yeung Endoscopic Spine Surgery system with 7 mm working sleeve and $25^{\circ}$ viewing angle was used. The mean follow up period was 6 months [range, 3-9]. Results : Operated levels were from T12-L1 disc down to L5-L6 of S1 disc. Of 71 cases, 2 patients underwent transforaminal endoscopic surgery twice due to recurrence after initial operation. MacNab's criteria was used to assess the outcome. Favorable outcome, excellent of good, was seen in 78% [57 procedures] of the patients. Among 11 fair outcomes, only 1 procedure was followed by secondary open procedure, laminectomy with discectomy. Two of 5 poor outcomes were operated again by same procedure which resulted in fair outcomes. One patient with aggravated cauda equina syndrome remained poor and a lumbar fusion procedure was performed in other patient with poor outcome. There were 2 postoperative discitis that were treated with conservative care in one and anterior lumbar interbody fusion in the other. Conclusion : Evolving technology of mechanical, visual instrument enables minimal invasive procedure possible and effective. The transforaminal endoscopic spinal surgery can reach as high as T12-L1 disc level. The rate of favorable outcome is mid-range among reported endoscopic lumbar surgery series. Authors believe that the outcome will be better as cases accumulate and will be able to reach the fate of standard open microsurgery.

• Cartoon and Animation Studies
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• s.34
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• pp.105-128
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• 2014

This study was aimed to analyze the disparities of 3D stereoscopic images in four well-known American animation movies. After Avatar (2009), lots of stereoscopic movies were developed in Korean 3D production. Almost all 3D productions in Korea, however, focus on the display images or TV series animation yet. In order to make many well-made Korean stereoscopic 3D animations in future, analyzing and comparing the disparities of 3D stereoscopic images is necessary and even mandated. First, I chose 40 cuts from each four American stereoscopic 3D feature films, including Despicable me 2, Epic, Monster University, and Turbo. According to the classifications of shot angles by Vineyard (2008), secondly I analyze the 23 different angular disparities of 3D stereoscopic images and displayed in tables. Demonstrated shot angle disparities in each scene would provide numerical information to animators how to design and make the 3D stereoscopic images. Making successful stereoscopic 3D feature film will be a huge turning point in the Korean animation field in future. This study would be a first trial to seek a new method to set ahead an outlook of numerical values of 3D stereoscopic images for better visual effects.

• Journal of Korean Neurosurgical Society
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• v.57 no.1
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• pp.36-41
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• 2015

Objective : To investigate the causes for failed anterior cervical surgery and the outcomes of secondary laminoplasty. Methods : Seventeen patients failed anterior multilevel cervical surgery and the following conservative treatments between Feb 2003 and May 2011 underwent secondary laminoplasty. Outcomes were evaluated by the Japanese Orthopaedic Association (JOA) Scale and visual analogue scale (VAS) before the secondary surgery, at 1 week, 2 months, 6 months, and the final visit. Cervical alignment, causes for revision and complications were also assessed. Results : With a mean follow-up of $29.7{\pm}12.1$ months, JOA score, recovery rate and excellent to good rate improved significantly at 2 months (p< 0.05) and maintained thereafter (p>0.05). Mean VAS score decreased postoperatively (p<0.05). Lordotic angle maintained during the entire follow up (p>0.05). The causes for secondary surgery were inappropriate approach in 3 patients, insufficient decompression in 4 patients, adjacent degeneration in 2 patients, and disease progression in 8 patients. Complications included one case of C5 palsy, axial pain and cerebrospinal fluid leakage, respectively. Conclusion : Laminoplasty has satisfactory results in failed multilevel anterior surgery, with a low incidence of complications.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.11
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• pp.14-19
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• 2013

Tunnel lighting design and operation are both regulated based on luminance in and out of Korea these days. However, domestic tunnel lighting is operated by internal lighting depending on external brightness by using an illuminometer applying the conversion factor on luminance. The purpose of tunnel lighting is to alleviate the visual shock occurring from the rapid change from external brightness to internal brightness when entering a tunnel. However, when looking at the tunnels operated based on an illuminometer, it is not a system where the driver can measure the brightness within his or her viewing angle when entering the tunnel. It is general to install and operate the illuminometer on the roof of an administrative office near the tunnel; however, this method is not structured to connect with the internal lighting by checking the brightness of the viewing scope of the driver, thus is not structured to properly apply the viewing conditions of the driver. Rather, it should be in a method for extracting the luminance value within the viewing scope of the driver pursuant to tunnel lighting standards and in connection with internal lighting. This research seeks to find the difference between operations based on luminance and operations based on intensity of Illuminance in road tunnels through field measuring, and to suggest the necessity of operating based on luminance with the resulting value.

• Journal of Korean Neurosurgical Society
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• v.53 no.1
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• pp.26-30
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• 2013

Objective : The purpose of this study was to compare the results of three types of short segment screw fixation for thoracolumbar burst fracture accompanying osteopenia. Methods : The records of 70 patients who underwent short segment screw fixation for a thoracolumbar burst fracture accompanying osteopenia (-2.5< mean T score by bone mineral densitometry <-1.0) from January 2005 to January 2008 were reviewed. Patients were divided into three groups based on whether or not bone fusion and bone cement augmentation procedure 1) Group I (n=26) : short segment fixation with posterolateral bone fusion; 2) Group II (n=23) : bone cement augmented short segment fixation with posterolateral bone fusion; 3) Group III (n=21) : bone cement augmented, short segment percutaneous screw fixation without bone fusion. Clinical outcomes were assessed using a visual analogue scale and modified MacNab's criteria. Radiological findings, including kyphotic angle and vertebral height, and procedure-related complications, such as screw loosening or pull-out, were analyzed. Results : No significant difference in radiographic or clinical outcomes was noted between patients managed using the three different techniques at last follow up. However, Group I showed more correction loss of kyphotic deformities and vertebral height loss at final follow-up, and Group I had higher screw loosening and implant failure rates than Group II or III. Conclusion : Bone cement augmented procedure can be an efficient and safe surgical techniques in terms of achieving better outcomes with minimal complications for thoracolumbar burst fracture accompanying osteopenia.

• Journal of Korean Neurosurgical Society
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• v.53 no.1
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• pp.19-25
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• 2013

Objective : We compared the results of two surgical techniques by retrospective study of 60 elderly patients (65 years or older) who underwent either decompression alone or fusion for the treatment of two-level or more lumbar spinal stenosis. Methods : During the period of 2003 and 2008, two-level or more decompression alone or fusion was performed for lumbar spinal stenosis by three surgeons at our institution. Patients were allocated to two groups by surgical modality, namely, to a decompression group (31 patients) or a fusion group (29 patients). Overall mean age was 71.1 years (range, 65-84) and mean follow-up was 5.5 years (range, 3-9). A retrospective review of clinical, radiological, and surgical data was conducted. Results : No significant difference between the two groups was found with respect to age, follow-up period, surgical levels, or preoperative condition. At the last follow-up, correction of lumbar lordotic angle (determined radiologically) was better in the fusion group. However, clinical outcomes including visual analogue scale, Oswestry Disability Index, and the Odom's criteria were not significantly different in the two groups. On the other hand, surgical outcomes, such as, operation time, estimated blood loss, and surgical complications were significantly better in the decompression alone group. Conclusion : Our findings suggest that decompressive laminectomy alone achieves good outcomes in patients with two-level or more lumbar spinal stenosis, associated with an advanced age, poor general condition, or osteoporosis.

• Journal of Korean Neurosurgical Society
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• v.53 no.1
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• pp.6-12
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• 2013

Objective : This consecutive retrospective study was designed to analyze and to compare the efficacy and outcomes of anterior cervical discectomy and fusion (ACDF) using a fibular and femur allograft with anterior cervical plating. Methods : A total of 88 consecutive patients suffering from cervical degenerative disc disease (DDD) who were treated with ACDF from September 2007 to August 2010 were enrolled in this study. Thirty-seven patients (58 segments) underwent anterior interbody fusion with a femur allograft, and 51 patients (64 segments) were treated with a fibular allograft. The mean follow-up period was 16.0 (range, 12-25) months in the femur group and 19.5 (range, 14-39) months in the fibular group. Cage fracture and breakage, subsidence rate, fusion rate, segmental angle and height and disc height were assessed by using radiography. Clinical outcomes were assessed using a visual analog scale and neck disability index. Results : At 12 months postoperatively, cage fracture and breakage had occurred in 3.4% (2/58) and 7.4% (4/58) of the patients in the femur group, respectively, and 21.9% (14/64) and 31.3% (20/64) of the patients in the fibular group, respectively (p<0.05). Subsidence was noted in 43.1% (25/58) of the femur group and in 50.5% (32/64) of the fibular group. No difference in improvements in the clinical outcome between the two groups was observed. Conclusion : The femur allograft showed good results in subsidence and radiologic parameters, and sustained the original cage shape more effectively than the fibular allograft. The present study suggests that the femur allograft may be a good choice as a fusion substitute for the treatment of cervical DDD.