• Sleep Medicine and Psychophysiology
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• v.17 no.1
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• pp.28-33
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• 2010

Objectives: Working at other times than the regular day shift has been reported to be a stressor associated with health consequences and mental disorders as well as disturbance of sleep. In current study, we aimed at investigating the relationship between work schedule, sleep quality and depression among police officers. Methods: Eleven hundreds and forty five police officers (male: 1040, female: 105) completed questionnaires of basic socio-demographic data, Pittsburgh Sleep Quality Index (PSQI), Korean Scale of Occupational Stress (KOSS), Impact of Event Scale - Revised (IES-R) and Center for Epidemiologic Study-Depression (CES-D). Results: After controlling for age, sex and educational level, score of CES-D was correlated positively with the score of KOSS, PSQI and IES-R on partial correlation analysis (r=-0.077; p=0.009, r=0.262; p<0.000 and r=0.421, p<0.000, respectively). Logistic regression analysis revealed that female sex, age, the score of KOSS and IES-R and schedule of rotating shift work predicted higher score than 16 score of CES-D significantly in total subjects (p=0.023, p=0.015, p=0.000, p=0.000 and p=0.022, respectively). Conclusion: Current result suggested that not only female sex, age, higher occupational stress and impact of event scale but also rotating shift work schedule might be related to depression among police officers.

• Journal of Korean Orthopaedic Sports Medicine
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• v.10 no.2
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• pp.78-85
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• 2011

Purpose: To evaluate the usefulness of computerized tomography (CT) for the diagnosis and the fragment fixation of anteroinferior tibiofibular ligament avulsion fracture in ankle fracture. Materials and Methods: We retrospectively studied 108 patients with an ankle fracture who had been checked with plain radiographs and CT from July 2006 to July 2010. They were divided into two groups; patients with (19 patients) and without (89 patients) an avulsion fracture of anteroinferior tibiofibular ligament. The two groups were evaluated with Lauge-Hansen classification, the energy of trauma, and the radiologic indices for syndesmotic injury, and were compared each other. Average follow up periods of two groups were 25 and 23 months each. Those who were unstable at stress test during surgery were divided into fragment fixation of anteroinferior tibiofibular ligament avulsion fracture group (8 patients) and transfixation one (11 patients) according to treatment method. Clinical and radiological results at last follow up were also compared. Results: Fourteen avulsion fractures of anteroinferior tibiofibular ligament were diagnosed by CT only. Incidences of pronation-external rotation injury, high energy trauma, positive radiologic indices for syndesmotic injury were significantly higher in patients with an avulsion fracture of anteroinferior tibiofibular ligament than those without it. Clinical and radiological results were satisfactory in both groups at last follow up, and were not significantly different between them. Conclusion: In patients who have an ankle fracture by pronation-external rotation injury, high energy trauma, or with positive radiologic indices for syndesmotic injury, CT is useful for diagnosis of an avulsion fracture of anteroinferior tibiofibular ligament. Fragment fixation of anteroinferior tibiofibular ligament avulsion fracture is a useful treatment option for syndesmotic injury.

• The Journal of Korean Society for Radiation Therapy
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• v.30 no.1_2
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• pp.65-71
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• 2018

Purpose : Standardized pillow may not support patient's individual cervical spine thoroughly when head and neck radiation therapy with $Tomotherapy^{(R)}$. Therefore, the purpose of this study was to make a comparative analysis for the difference of using standardized pillow only and using customized cervical spine immobilizer with standardized pillow. Materials and Methos : The head and neck cancer patients who are treated image-guided radiation therapy(IGRT) with $Tomotherapy^{(R)}$ were divided into two groups, 20 patients using standardized pillow only, and 20 patients using customized cervical spine immobilizer with standardized pillow. We achieved 20 mega-voltage computed tomography(MVCT) image per patient, compared curvature of the cervical spine in MVCT with curvature of the cervical spine in CT-simulation. Results : Results of comparative analysis were curvature consistency 95.9 %, maximum error of distance 41.9 mm, average distance error per fractionation 19.4 mm, average standard deviation 1.34 mm in case of using standardized pillow only, curvature consistency 98.9 %, maximum error of distance 12.9 mm, average distance error per fractionation 5.8 mm, average standard deviation 0.59 mm in case of using customized cervical spine immobilizer with standardized pillow. Conclusion : Using customized cervical spine immobilizer shows higher reproducibility and low distance error, therefore customized cervical spine immobilizer could be useful for head and neck cancer patients who need radiation therapy.

• Journal of Navigation and Port Research
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• v.37 no.3
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• pp.257-262
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• 2013

A ship operating in rough sea may suffer from an undesirable motion which may severely degrade the performance of equipment onboard and give a person an uncomfortable feeling. Hence, roll stabilization received a considerable attention and various devices including bilge keels, stabilizing fins, gyroscopic, anti-rolling tanks, rudders and flaps have been conceived and utilized for the purpose. The Coanda effect is evident when a jet stream is applied tangential to a curved surface of a hydrofoil since then the jet increases the circulation around the foil and consequently the lift. Model tests and numerical simulation have been conducted to examine the practicality of a fixed type fin stabilizer augmented by the Coanda jet. The results show that the lift coefficient of the modified Coanda fin at the zero angle of attack identically coincides with that of the original fin at ${\alpha}=\26^{\circ}$ when Coanda jet is supplied at the rate of $C_j$ = 0.25. It is also shown that fixed type fin stabilizers for active control of the motions of ships and the other mobile units without rotation can be put to practical use if the Coanda effect is applied.

• The Journal of Korean Society for Radiation Therapy
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• v.18 no.2
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• pp.89-96
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• 2006

Purpose: To study effectiveness of heterogeneity correction of internal-body inhomogeneities and patient positioning immobilizers in dose calculation, using images obtained from CT-Simulator. Materials and Methods: A water phantom($250{\times}250{\times}250mm^3$) was fabricated and, to simulate various inhomogeneity, 1) bone 2) metal 3) contrast media 4) immobilization devices(Head holder/pillow/Vac-lok) were inserted in it. And then, CT scans were peformed. The CT-images were input to Radiation Treatment Planning System(RTPS) and the MUs, to give 100 cGy at 10 cm depth with isocentric standard setup(Field Size=$10{\times}10cm^2$, SAD=100 cm), were calculated for various energies(4, 6, 10 MV X-ray). The calculated MUs based on various CT-images of inhomogeneities were compared and analyzed. Results: Heterogeneity correction factors were compared for different materials. The correction factors were $2.7{\sim}5.3%$ for bone, $2.7{\sim}3.8%$ for metal materials, $0.9{\sim}2.3%$ for contrast media, $0.9{\sim}2.3%$ for Head-holder, $3.5{\sim}6.9%$ for Head holder+pillow, and $0.9{\sim}1.5%$ for Vac-lok. Conclusion: It is revealed that the heterogeneity correction factor calculated from internal-body inhomogeneities have various values and have no consistency. and with increasing number of beam ports, the differences can be reduced to under 1%, so, it can be disregarded. On the other hand, heterogeneity correction from immobilizers must be regarded enough to minimize inaccuracy of dose calculation.

• Tuberculosis and Respiratory Diseases
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• v.60 no.4
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• pp.412-418
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• 2006

Background; The diagnosis of chlamydial infection is based on serology. The current gold standard of diagnosis is MIF(microimmunofluorescence), but this modality is subjective and time-consuming. Protein microarray with using a SPR(surface plasmon resonance) sensor has recently been suggested as a method for detecting infection. For developing a protein chip to diagnose chlamydial infection, EBs(elementary bodies) were immobilized on a gold chip and the interaction between an antibody for Chlamydophila pneumoniae and the EBs(elementary bodies) immobilized on the surface of the gold chip was measured by using an SPR sensor. Methods; For the surface antigen, the EBs of Chlamydophila pneumoniae LKK1 were purified. Charged arrays were prepared by using PDDA(polydiallyldimethylammonium chloride) which has a positive charge. After immobilization of the chlamydial EBs on the PDDA surface, the investigation of the surface was done with using atomic force microscopy. After the antibody for C. pneumoniae was applied on chip, we monitored the SPR wavelength-shift to detect any antigen-antibody interaction with using a self-assembled SPR sensor. Results; The chlamydial EBs on the positively charged PDDA were visible on the surface with using atomic force microscopy. The SPR wavelength increased after interaction of antibody for C. pneumoniae with the EBs immobilized on charged gold surface. The wavelength-shift was correlated with the concentration of antigens. Conclusion; The surface immobilization of EBs on the gold surface with the charged arrays was identified and the antigen-antibody interaction on the gold chip was detected via the SPR sensor. Further investigations are needed to apply this technique to the clinical field.

• The Journal of Korean Society for Radiation Therapy
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• v.17 no.1
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• pp.45-55
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• 2005

Purpose : To evaluate the usefulness of the handmade patient immobilization device and to report the clinical results of it. Materials and methods : We made two fusion images and analyzed those images. One image is made with diagnostic MR image and CT image, the other with therapeutic planning MR image and CT image. With open head holder, we measured the skin dose and attenuation dose. Also, we made the planning CT couch plate with acrylic plate and styrofoam and compared artifact. Results : We could get more accurate fusion image when we use MR head holder(within 2mm error). The skin dose was reduced 2 times and the attenuation dose was reduced more than $20\%$ when open head holder used. The planning CT couch plate was more convenient than conventional board and reduced artifact remarkably. Conclusion : We could verify the localization point in the MR image which is taken with MR head holder. So we could fuse the image more accurately. The same method could be applied to PET and US image, if the alike immobilization device used. With open head holder, the skin dose and the attenuation dose was reduced. And those above devices could substitute for expensive foreign device, if those are manufactured adequately.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.37 no.2
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• pp.95-105
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• 2001

A series of experiment is carried out to determine the holding power of the existing anchors used in the stationary gear in the coast of the South sea. The experiment apparatus is made of the pulling machine, the load cell, the personal computer and three water tanks the bottom of which are mud, sand and m & s respectively. The result obtained are as follows : 1. On the tension and holding power of the existing anchors, B-type of the stock anchor with two fluke shows the greatest and gets smaller on order of A-type one with a fluke. The holding power of the anchors shows the greatest in the mud and gets smaller in order of m & s, sand. And, the holding power depending upon the length of anchor rope increase as the length does up to the 4 times of depth. 2. On the holding power per fluke area of the existing anchors in case of ration of length of anchor rope to depth is 2, 3 and 4, A-type anchor shows about 310-320 kg/m supper(2), 470-480 kg/m supper(2), 590-640 kg/m supper(2) respectively, B-type one 260-265 kg/m supper(2), 390-450 kg/m supper(2), 630-700 kg/m supper(2) respectively, and C-type one 70-100 kg/m supper(2), 150-180 kg/m supper(2), 210-270 kg/m supper(2) respectively. The holding power per fluke area of the anchors increase as the length of anchor rope does. 3. On the coefficient of holding power of the existing anchors, A-type anchor shows the greatest and gets smaller in the order of B-type one, C-type one.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.1
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• pp.50-57
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• 2008

Winter season cultivation of rye as green manure for soybean have been a favorite with farmer because it could remove a risk of injury by continuous cropping and increase N uptake and yield of soybean. Effects of rye green manure on soybean N uptake, $N_2$ fixation and yield were investigated with $^{15}N$ as pot experiment in greenhouse in 2004 and field in 2005, respectively. The N derived from N fertilizer ($^{15}N$) in rye green manure increased with increasing of N fertilizer rate compared to N derived from soil. N uptake and DM yield of soybean at the pot with paddy soil was higher than those at the pot with upland soil mainly due to the increase of N uptake from paddy soil. Total $^{15}N$ recovery in soil was higher at rye green manure than no green manure because $^{15}N$ applied to rye plant was remained highly as soil organic N compared to chemical N fertilizer. $^{15}N$ recovery in soybean plant increased in proportion to amounts of N fertilizer applied to rye. The N fractions from $N_2$ fixation of soybean plant at the pot experiment in 2004 ranged from 92% to 95%, on the other hand those in field experiment in 2005 ranged from 82% to 84%. Estimation of amount of $N_2$ fixation was not different between Difference method and $^{15}N$ method in 2004 and 2005.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.228-228
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• 2009

In stator windings of a 6.6kV rotating machine, internal discharge, corona discharge, and surface discharge are mainly caused by internal voids and insulation degradation. In the case of the discharge spark and electromagnetic pulse generated from a discharge source, we can detect it using various RF resonators like an EM sensor. In order to detect these types of electromagnetic sources, we designed and fabricated a planar patch sensor using a CST-MWS simulation, and PD signals from artificial defected stator windings were also measured by the sensor proposed in this study. Furthermore, In the results of the experiment, it showed similar performance to the HFCT sensor.