• Journal of Korean Ophthalmic Optics Society
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• v.16 no.4
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• pp.409-415
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• 2011

Purpose: To design applied anamorphic lens that focal length ratio is 3:1 optical system to improve detecting distance. Methods: We defined a boundary condition as $50^{\circ}{\sim}60^{\circ}$ for viewing angle, horizontal direction 36mm, vertical direction 12 mm for focal length, f-number 4, $15{\mu}m{\times}15{\mu}m$ for pixel size and limit resolution 25% in 33l p/mm. Si, ZnS and ZnSe as a materials were used and 4.8 ${\mu}m$, 4.2 ${\mu}m$, 3.7 ${\mu}m$ as a wavelength were set. optical performance with detection distance, narcissus and athermalization in designed camera were analyzed. Results: F-number 4, y direction 12 mm and x direction 36 mm for focal length of the thermal optical system were satisfied. Total length of the system was 76 mm so that an overall volume of the system was reduced. Astigmatism and spherical aberration was within ${\pm}$0.10 which was less than 2 pixel size. Distortion was within 10% so there was no matter to use as a thermal optical camera. MTF performance for the system was over 25% from 33l p/mm to full field so it was satisfied with the boundary condition. Designed optical system was able to detect up to 2.9 km and reduce a diffused image by decreasing a narcissus value from all surfaces except the 4th surface. From sensitivity analysis, MTF resolution was increased on changing temperature with the 5th lens which was assumed as compensation. Conclusions: Designed optical system which used anamorphic lens was satisfied with boundary condition. an increasing resolution with temperature, longer detecting distance and decreasing of narcissus were verified.

• Journal of Chest Surgery
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• v.43 no.6
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• pp.681-686
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• 2010

Background: A chest computed-tomography has become more prevalent so that it is more common to detect small sized pulmonary nodules that have not been found in previous simple chest x-ray. If those detected nodules are undersized or located in pulmonary parenchyma, it is difficult to accomplish a biopsy since it is vulnerable to explore them either grossly or digitally. Thus, in our hospital, a thoracoscopic pulmonary wedge resection was performed after locating a lesion by means of hook wire with CT-guided. Material and Method: 31 patients (17 males and 14 female patients) from December in 2006 to June in 2010 became our subjects; their 34 pulmonary nodules were subjected to the thoracoscopic pulmonary wedge resection after locating a lesion by means of hook wire with CT-guided. Also we analyzed a possibility of hook wire dislocation, a frequency of conversion to open thoracotomy, time consumed to operation after location of a lesion, operation time, post operation complication, and histological diagnosis of the lesion. Result: 12 of 34 cases were ground glass lesion, whereas 22 cases of them were solitary pulmonary lesion. The median value of the lesion was 8mm in size (range: 3 to 23 mm), while the median value was 12.5 mm in depth (range: 1 to 34 mm). The median value of time consumed from location of the lesion to anesthetic induction was 86.5 minutes (41~473 minutes); furthermore the mean value of operation time was 103 minutes (25~345 minutes). Intrathoracic wire dislocation was found in one case, but a target lesion was successfully excised. Open thoracotomy was performed in four cases due to pleural adhesion. However, there was no case of conversion to open thoracotomy due to failure to detect a target lesion. In histological diagnosis, metastatic cancer were found in 15 cases, which were the most common, primary lung cancer were in 9 cases, non-specific inflammation were in 3 cases, tuberculosis inflammation were in 2 cases, lymph nodes were in 2 cases, active tuberculosis were in 1 case, atypical adenomatous hyperplasia was in 1 case and normal lung parenchymal finding was in 1 case, respectively. Conclusion: In our hospital, in order to accomplish a precise histological diagnosis of ground-glass lesion and pulmonary nodules in lung parenchyma, location of pulmonary nodules were exactly located with hook wire under chest computed-tomography, which was followed by lung biopsy. We concluded that this was an accurate, minimally invasive and valuable method to minimize the complications and increase of cost of medical service provided.

• Journal of Chest Surgery
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• v.43 no.6
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• pp.710-715
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• 2010

Background: Video-assisted thoracic surgery (VATS) became common in the treatment of spontaneous pneumothorax (SP). Therefor we've reviewed the recurrence rate after VATS and analysed the factors affecting recurrent pneumothorax after VATS on this study. Material and Method: This retrospective analysis was performed on 321 patients of SP who had undergone VATS from Jan. 2001 to Dec. 2008. The two groups were divided as follow: group A, non-recurrent group (298 patients: 93%); and group B, recurrent group (26 patients: 7%); the two groups were analysed retrospectively. Result: The average age of the study groups were $20.9{\pm}4.3$ years old in recurrent group vs. $25.9{\pm}11.7$ years old in non-recurrent group with statistical significance (p < 0.05). There were no statistical significance in male to female ratio, height/weight ratio, location of pneumothorax, smoking history, operative time, duration of drain, hospital stay, indication of opertion and incidence rate. Average length of duration in recurrence was 12.9 months. There was 22 (95.7%) recurrent patients after VATS within 4 year period among recurrent group. Treatment methods in 23 of recurrent patients were, 8 (VATS), 2 (Axillary thoracotomy) with 15% or more in amount of pneumothorax and 7 (7 Fr. chest tube), 6 (nasal 02) with 15% or less in amount of pneumothorax. Among 10 cases of reoperation, there were 3 cases of over looking type and 7 cases of new growing type. There was no additional recurrence after these procedures were given. Conclusion: There was higher recurrence rate in younger age after VATS thus for those under 20 yrs old, detailed and possible preoperative warning for recurrence is warranted. Most recurrence occured within 4 year period, thus for this reason, regular interval based follow up with chest x-ray study is suggested during this period.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.3 no.1 s.4
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• pp.85-96
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• 2004

The study begin with a basic concept, if the occupancy length of vehicle detector is directly proportional to the delay of vehicle. That is, it analogize vehicle's delay of a occupancy time. The results of a study was far superior in the estimation of a queue length. It is a very good points the operator is not necessary to optimize s1, s2, Thdoc. Thdoc(critical congestion degree) replaced 0.7 with 0.2 - 0.3. But, if vehicles have been experience in delay was not occupy vehicle detector, the study is in existence some problems. In conclusion, it is necessary that stretch queue detector or install paired queue detector. Also I want to be made steady progress a following study relation to this study, because it is required traffic signal control on congestion.

• The Korean Journal of Malacology
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• v.32 no.3
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• pp.231-240
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• 2016

Techniques were developed for holding and conditioning of Pacific oysters, Crassostrea gigas, in a closed recirculating system. Experimental adults were used 500 oysters ( x two system, total 1,000 oysters) which were collected in $20^{th}$ March 2016 from long-line aquaculture farm at the south coast of Korea. During conditioning periods concentrated live microalgae as Isochrysis sp. $15{\times}10^7cells/mL$, Tetraselmis sp. $2{\times}10^7cells/mL$ and Pheaodactylum sp. $18{\times}10^7cells/mL$ were added 5 L every day, respectively which micro algae were functioned as diets and biological filter. Over all experimental periods total water exchange rate was 21.3% (daily 0.5%). Over 42 days conditioning, female and male oysters were maturated 90.9% and 94.4%, respectively. Survival rate was 98.7%. Mean shell hight (8.3 mm), total wet weight (19.2 g), meat wet weight (5.0 g) and shell wet weight (13.6 g) were significantly increased (P < 0.05). Water quality parameters including the water temperature ($22.1{\pm}0.4^{\circ}C$), salinity ($24.9{\pm}04$), dissolved oxygen (5.1-7.9 mg/L) and pH ($7.93{\pm}0.15$) were kept stable. Concentration of dissolved inorganic nutrient as ammonia (1.96-0.35 mg/L), nitrite (0.03-0.16 mg/L), nitrate (1.34-0.47 mg/L), DIP (0.42-0.03 mg/L) and silicate (3.83-0.00 mg/L) were significantly decreased throughout experiment except nitrite which was increased (P < 0.05), but nitrogenous components stayed below toxic levels (ammonia 0.0-5.5 mg/L, nitrite 0.0-460.0 mg/L) which indicated that closed recirculation system with microalgae based bio-filter could supply sufficiently environment condition to holding and conditioning of oyster.

• Analytical Science and Technology
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• v.28 no.6
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• pp.398-408
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• 2015

Carbon monoxide (CO) intoxication, arising from CO from an ignited charcoal briquette (ICB), is a popular means of committing suicide in Korea. Most CO intoxications are related to suicide attempts; however, the possibility of a homicide disguised as a suicide cannot be ruled out. Therefore, forensic investigation of the deceased and the crime scene is crucial to confirm that the deceased committed suicide. Detection of the components of an ICB on the objects suspected of being contacted by the deceased, such as the hands, nostrils, and doorknobs, is essential for linking the crime scene to the victim in the case of suicides by ignited ICBs. The traces from an ICB were analyzed by investigating the morphological characteristics and obtaining elemental compositions. The ICBs were completely different from blackened wood, as detected by discriminant analysis with the elements of carbon and oxygen. We analyzed one case of CO intoxication to demonstrate an excellent procedure for verifying whether a suicide occurred with an ICB. We employed SEM-EDX for the analysis of an ICB, microscope-FT/IR and pyrolysis-GC/MS for a partly burnt resin-type substance, GC/MS for diphenhydramine (a sleeping drug), and GC/TCD for the CO-Hb level. We detected traces of an ICB on the hands, nostrils, and doorknobs, which were all discriminated into an ICB group. Detection of ICB traces from the nostrils could indicate that the deceased started the fire themselves to commit suicide. The partially burnt black material was analyzed as an acrylronitrilestyrene polymer, which is normally used to make bags for carrying or wrapping and could be assumed to have been used to transport the ICB. Diphenhydramine, a sleeping drug, was detected at a level of 2.3 mg/L in the blood, which was lower than that in fatal cases (8-31 mg/L; mean 16 mg/L). A CO-Hb level of 79% was found in the blood, which means that the cause of death was CO intoxication. The steps shown here could represent an ideal method for reaching a verdict of suicide by CO intoxication produced by burning an ICB in a sealed room or a car.

• Radiation Oncology Journal
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• v.21 no.3
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• pp.199-206
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• 2003

Purpose: This study was undertaken to evaluate the efficacy of postoperative radiotherapy, and to investigate the prognostic factors for FIGO stages IB-IIB cervical cancer patients who were treated with simple hysterectomy, or who had high-risk factors following radical hysterectomy and pelvic lymph node dissection. Materials and Methods: Between March 1986 and December 1998, 58 patients, with FIGO stages IB-IIB cervical cancer were included in this study. The indications for postoperative radiation therapy were based on the pathological findings, including lymph node metastasis, positive surgical margin, parametrial extension, lymphovascular invasion, invasion of more than half the cervical stroma, uterine extension and the incidental finding of cervix cancer fellowing simple hysterectomy. All patients received external pelvic radiotherapy, and 5 patients, received an additional intracavitary radiation therapy. The radiation dose from the external beam to the whole pelvis was $40\~50$ Gy. Vagina cuff Irradiation was peformed, after completion of the external beam irradiation, at a low-dose rate of Cs-137, with the total dose of $4488\~4932$ chy (median: 4500 chy) at 5 mm depth from the vagina surface. The median follow-up period was 44 months ($15\~108$ months). Results: The 5-yr actuarial local control rate, distant free survival and disease-free survival rate were $98\%,\;95\%\;and\;94\%$, respectively. A univariate analysis of the clinical and pathological parameters revealed that the clinical stage (p=0.0145), status of vaginal resection margin (p=0.0002) and parametrial extension (p=0.0001) affected the disease-free survival. From a multivariate analysis, only a parametrial extension independently influenced the disease-free survival. Five patients ($9\%$) experienced Grade 2 late treatment-related complications, such as radiation proctitis (1 patient), cystitis (3 patients) and lymphedema of the leg (1 patient). No patient had grade 3 or 4 complications. Conclusion: Our results indicate that postoperative radiation therapy can achieve good local control and survival rates for patients with stages IB-IIB cervical cancer, treated with a simple hysterectomy, as well as for those treated with a radical hysterectomy, and with unfavorable pathological findings. The prognostic factor for disease-free survival was invasion of the parametrium. The prognosic factor identified in this study for treatment failure can be used as a selection criterion for the combined treatment of radiation and che motherapy.

• The korean journal of orthodontics
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• v.29 no.2 s.73
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• pp.183-195
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• 1999

Growth and development evaluation of patients with growth potential is of great importance for orthodontic treatment planning. Timing of orthodontic intervention greatly depends on one's developmental status, thus if there is a difference in skeletal maturation among malocclusion types different treatment timing should be applied. The objective of this study was to evaluate and compare skeletal maturation among different malocclusion types. The samples used in this study was 38 Class I, 36 Class II and 33 ClassIII females aging from 8 to 10 years. Handwrist X-rays were taken with 6 month interval till 12-13 years of age. The results were as follows. 1. There was no skeletal maturity difference among different malocclusion types. 2. The hamular process of hamate was observed at $9.16{\pm}0.72$ years, pisiform bone at $9.13{\pm}0.71$ years and the ulnar sesamoid at $10.34{\pm}0.84$ years. 3. The timing of epiphyseal capping on the third finger was $10.96{\pm}0.80$ years for distal phalanx and $11.27{\pm}0.87$ years for middle phalanx, $11.12{\pm}0.85$ years for proximal phalanx of the first finger, $11.21{\pm}0.82$ years for radius and $11.62{\pm}0.85$ years for middle phalanx of the fifth finger. 4. The appearance of pisiform bone showed high correlation with appearance of hamular process of hamate(r=0.91) and ulnar sesamoid bone appearance showed high correlation with advanced ossification of hamular process(r=0.86). Timing of epiphyseal capping among different parts showed high correlation(r=0.80-0.90). 5. The shape of middle phalanx of the fifth finger showed the highest variability ($20.6\%$).

• Sleep Medicine and Psychophysiology
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• v.15 no.2
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• pp.94-99
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• 2008

The most common cause of obstructive sleep apnea syndrome (OSAS) in childhood is adenotonsillar hypertrophy. Adenotonsillectomy improves the symptoms quite well in most cases. However, some patients could experience the OSAS again after adenotonsillectomy, who might have several risk factors such as incomplete operation, misdiagnosis, combined anatomical malformation, sinusitis or chronic allergic rhinitis, obesity, initial severe OSAS, and early onset OSAS. We report a case of 11-year-old obese boy who presented with snoring for several years. He was obese with body mass index (BMI) of $26.3kg/m^2$ and also found to have fatty liver by ultrasonogram. Initial polysomnography (PSG) showed that he met the criteria of severe OSAS with the apnea-hypopnea index (AHI) of 70.5. He underwent adenotonsillectomy and symptoms improved immediately. Four months later symptoms were relieved with AHI of 0, but 1 year after the adenotonsillectomy he started to complain snoring again and the subsequent PSG results showed that OSAS has relapsed with AHI of 43. Paranasal sinus X-ray and physical examination showed sinusitis and re-growth of adenoid. Obesity was proved not to be a contributing factor because his BMI decreased to normal range ($23.1kg/m^2$) after diet control and regular exercise. Also, liver transaminase was normalized and fatty liver was disappeared on follow-up abdominal ultrasonogram. After treatment of sinusitis, symptoms were relieved with decreased AHI (8.5). This case suggests that simple adenotonsillectomy might not be the end of OSAS treatment in childhood. Patients who had adenotonsillectomy should be followed by subsequent PSG if symptoms recur. It is also important to be aware of risk factors in the recurrent OSAS for the proper intervention according to the cause.

• Sleep Medicine and Psychophysiology
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• v.15 no.2
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• pp.87-93
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• 2008

Introduction: Although it is well known that medical students are not getting an adequate amount of sleep, there have been only few studies on the sleep patterns of medical students in Korea. Therefore, the present study aimed to investigate the life style and sleep patterns of Korean medical students and the impact they have on the students' academic performance. Methods: A questionnaire package was administered to the $3^{rd}$ year medical students at the Seoul National University to examine their sleep patterns on weekdays and weekends. It consisted of questions asking about their lifestyles as well as Pittsburgh sleep quality index (PSQI) and GPA (Grade Point Average) that are considered relevant to their sleep patterns. A total of 110 students (85 males and 25 females, mean age $24.4{\pm}20.6$) responded to the survey and the result was analyzed using the independent t-test, the chi-square test, the paired t-test, Pearson's rank correlation and ANOVA. P-values of less than 0.05 were considered statistically significant in all analyses. Results: The weekend bedtime was significantly delayed (01：24 on weekday；03：12 on weekend; t=-5.23, p<0.01), the weekend rise time was delayed (07：36 on weekday；10：30 on weekend ; t=-24.48, p<0.01) and the total sleep time was increased on weekends (5：57 on weekday；8：17 on weekend ; t=15.94, p<0.01). They wished to sleep for 7 hours 6 minutes which was different from their actual weekday total sleep time (t=-11.41, p<0.01). The poor sleeper group had lower GPAs than the good sleeper group (t=2.05, p<0.05). The GPA of medical students were negatively correlated with age (r=-0.23, p<0.05), daily amount of smoking (r=-0.78, p<0.01), total amount of smoking (r=-0.75, p<0.01), weekday sleep latency (r=-0.23, p<0.05), weekend sleep latency (r=-0.23, p<0.05) and PSQI score (r=-0.30, p<0.01). Conclusion: Medical students were experiencing a lack of sleep during weekdays as they have a later bedtime and earlier rise time, and consequently had more hours of sleep on weekends. Overall, the responded students were experiencing poor sleep quality, and the GPAs of the poor sleeper group were lower than those of the good sleeper group.