• The Journal of Korean Society for Radiation Therapy
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• v.19 no.1
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• pp.1-5
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• 2007

Purpose: The accuracy and advantages of OBI(On Board Imager) against the conventional method like film and EPID for the setup error correction were evaluated with the analysis of the accumulated data which were produced in the process of setup error correction using OBI. Materials and Methods: The results of setup error correction using OBI system were analyzed for the 130 patients who had been planned for 3 dimensional conformal radiation therapy during March 2006 and May 2006. Two kilo voltage images acquired in the orthogonal direction were fused and compared with reference setup images. The setup errors in the direction of vertical, lateral, longitudinal axis were recorded and calculated the distance from the isocenter. The corrected setup error were analyzed according to the lesion and the degree of shift variations. Results: There was no setup error in the 41.5% of total analyzed patients and setup errors between 1mm and 5mm were found in the 52.3%. 6.1% patients showed the more than 5mm shift and this error were verified as a difference of setup position and the movement of patient in a treatment room. Conclusion: The setup error analysis using OBI in this study verified that the conventional setup process in accordance with the laser and field light was not enough to get rid of the setup error. The KV images acquired using OBI provided good image quality for comparing with simulation images and much lower patients' exposure dose compared with conventional method of using EPID. These advantages of OBI system which were confirmed in this study proved the accuracy and priority of OBI system in the process of IGRT(Image Guided Radiation Therapy).

• Journal of the Korean earth science society
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• v.21 no.6
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• pp.663-674
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• 2000

A total of 165 independently oriented core samples were collected from 19 Cretaceous Yuchon Group sites in Kosong area, the southernmost part of the Miryang subbasin of the Kyongsang Basin in southern Korea. Stepwise AF and thermal cleaning revealed antipodal ChRM from 95 samples from 14 sites. Mean ChRM direction is d=26.0$^{\circ}$, i=49.4$^{\circ}$ (${\alpha}_{95}$=8.2$^{\circ}$, k=24.5, n= 14) before bedding correction and d=28.1$^{\circ}$, i=54.2$^{\circ}$ (${\alpha}_{95}$=4.8$^{\circ}$, k=70.6, n= 14) after bedding correction. A 2.88-fold increase of the precession parameter k by bedding correction indicates pre-folding age of the ChRM with 99% confidence level. Palaeomagnetic pole position calculated from the mean ChRM is 67.0$^{\circ}$N, 210.6$^{\circ}$E (dp=4.7$^{\circ}$, dm=6.7$^{\circ}$), which is significantly different neither from the poles of other part of the Kyongsang Basin nor those of Eurasia including SCB and NCB. This suggests stable relative position of the study area with regard to other parts of the Kyongsang Basin as well as to Eurasia continent since Cretaceous. Three ploarity reversals in the Kosong Formation in addition to the coexistence of normal and reversed polarities in the overlying Andesites and Welded Tuff suggest, in reference to the worldwide geomagnetic polarity time scale, an Albian to Maastrichtian (polarity chron 32r-31r) age of the Yuchon Group of the study area. An alleged hypothesis of stratigraphical correspondence between the Kosong Formation in the study area and the Tadaepo Formation in Pusan area is, however, not tenable: Not only because the latter shows a short reverse polarity only in its lowest part of the sequence but also because the Andesites overlying it is wholly normally magnetized, in contrast to the frequent reverals in the case of both the Kosong Formation and Andesites above it.

• Journal of the East Asian Society of Dietary Life
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• v.13 no.4
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• pp.267-283
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• 2003

This study reviewed the prisoners' dietary lift status under the world panics and Japanese food shortage based on the data of the 1920~1930's prisons' main dish supplies in Chosun, Shinchu boys' prison in Taiwan, Franue correction center in France and Moabit detention house in Germany. 1. The status of main dish food supply of Chosun prisons in 1920~1930's was as follows: 1) Meals were provided with 12 rates depending on the working activities. There were big differences in energy supply between 1$^{st}$ rate of 6045.0 ㎉ in the Mockpo prison and 12$^{th}$ rate of 1855.8 ㎉ in the Masan prison in accordance with the grain supply ratio and the diet rates. 2) The average ratio of energy provided with protein, fat and carbohydrate(PFC ratio) was 20.0: 20.2: 59.8. The supplies of protein and fat were relatively high because main dish was mostly composed of soybean. The soybean was used in 20 ~60％ of main dish in prisons except Gaesung. 3) It was estimated that PFC ratio(8.3: 8.1 : 83.6) in Gaesung boys' prison was not appropriate for growing boys because the soybean supply was low. 2. The overall comparison of nutrition supply of prisons in Chosun, Taiwan, France and Germany was as follows: 1) The daily supplies of energy in Keongsung prison was 3966.5 ㎉, of which the PFC ratio was 18.9: 16.6: 64.5. This showed that the PFC ratio seemed to be balanced, even though the total amount of energy is too high and the ratios of protein and fat were somewhat high and somewhat low, respectively. 2) The main dish of the Taiwan boys' prison was provided with 6 rates and the side dish in the from of weekly cycle menu. The energy intakes from 1$^{st}$ rate of 2862.9 ㎉ to 6$^{th}$ rate of 1388.9 ㎉ were not quite enough for growing boys. It was estimated that the amounts of protein and fat taken were small but the quality was not that bad because animal protein such as protein small fish and fried tofu were supplied. 3) In the French Frenue correction center and the German Moabit detention house, the daily total amounts of energy were 2771.3 ㎉ and 2678.7 ㎉, respectively, which was estimated as appropriate compared with standard energy amount of 3000 ㎉ at that time and the current energy RDA of 2500 ㎉ for adult. The ratio of PFC was 16.2: 12.0: 71.8 in Frenue correction center and 12.4: 14.3: 73.3 in Moabit detention house, which showed that the amount of fat was slightly lacked. From this study, it was suggested that the prisons in Chosun and Taiwan under the Japanese rule and European prisons after the world panic were making an efforts to supply prisoners the appropriate amount of energy. The only question remains is that this data may be from only the food supply plan not from the data the prisoners took in real.eal.

• Journal of Korean Dental Science
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• v.3 no.1
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• pp.32-38
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• 2010

Objective : To evaluate the relationship between the dose of Clodronate and serum level of alkaline phosphatase (ALP), calcium (Ca), and phosphate (PO4) during orthodontic tooth movement MaterialS and MethodS: A total of 18 sex-matched Wistar rats (weight=180~230g, mean age=8 weeks) were allocated into the 2.5mM Clodronate (2.5C) group, 10mM Clodronate (10C) group, or control group (n=6 for each group). After the application of a nickel-titanium closed coil spring (force of 60g) between the upper central incisors and first molars (UFM), 2.5C, 10C, or saline was injected every third day into the subperiosteum of the alveolar bone adjacent to UFM for the experimental and control groups. The animals were sacrificed 17 days later. Trunk blood was quickly collected into a heparinized tube and centrifuged at 2,000 rpm for 20 min. The plasma was used for the biochemical assays of the serum level of ALP, Ca, and PO4. Kruskall-Wallis test and Mann-Whitney test with Bonferroni correction were performed for the statistical analyses. Results : Dose-dependent increase in the level of ALP (P<0.01) and decrease in the level of Ca (P<0.001) were observed among the control, 2.5C, and 10C groups. Although there was no significant difference in PO4 between the 2.5C and 10C groups, the 10C group showed a significantly higher level of PO4 than the control group (P<0.01). Conclusion : Since Clodronate induced significant dose-dependent change in the serum level of ALP, Ca, and PO4 during orthodontic tooth movement, orthodontists should consider these biochemical markers not only as a diagnostic tool for bone turnover rate but also as a monitoring tool for orthodontic tooth movement.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.3
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• pp.223-227
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• 2016

Power supplies make the load compatible with its power source. DC power supplies are extensively used with most electrical and electronic appliances such as computers, television, and audio sets. The presence of non-linear loads results in a low power factor and higher harmonics in the power system. Several techniques for power-factor correction and harmonic reduction have been reported in the literature. This paper proposes a bridgeless boost converter that improves the power factor and reduces the harmonic content in input line currents as compared to full-bridge rectifiers. This bridgeless boost converter eliminates the need of a line-voltage bridge rectifier in conventional boost converter and thereby reduces conduction losses. The effectiveness of the proposed scheme is verified by computer simulations by using the PSIM software.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.11 no.1
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• pp.189-196
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• 1991

The objective of this study was to investigate the effect of temperature on microbial characteristics and treatment efficiency in aerated submerged biofilm process. From the results of the research, conclusions were derived as following: 1. Biofilm density, attached biomass and biofilm thickness were $30-42mg/cm^3$, $1.2-2.7mg/cm^2$ and $380-690{\mu}m$, respectively. These were greatly affected by the variation of temperature ($5-20^{\circ}C$) and packing ratio(45-90%). 2. The ratio of suspended biomass to the total biomass in the reactor was in the range of 10 to 50 % in accordance with the variation of temperature and packing ratio. Therefore, the portion of suspended biomass cannot be neglected. 3. BOD removal efficiency increased as either temperature or biomass(suspended and attached) concentration increased. 4. The aerated submerged biofilm process appeared to be less affected by temperature variation and the estimated temperature correction coefficient of the Van't Hoff-Arrhenenius equation was 1.042.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.4
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• pp.73-84
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• 2015

An embankment raising project on 113 agricultural reservoirs in Korea was implemented in 2009 to increase water supply capacity for agricultural water and instream uses. This study evaluated the future water supply capacity of the Imgo reservoir at which the agricultural reservoir embankment raising project was completed, considering climate change scenarios. The height of the embankment of the reservoir was increased by 4.5 m, thereby increasing its total storage from 1,657.0 thousand to 3,179.5 thousand cubic meters. To simulate the reservoir water storage with respect to climate changes, two climate change scenarios, namely, RCP 4.5 and RCP 8.5 (in which greenhouse gas reduction policy was executed and not executed, respectively) were applied with bias correction for reflecting the climate characteristics of the target basin. The analysis result of the agricultural water supply capacity in the future, after the agricultural reservoir embankment raising project is implemented, revealed that the water supply reliability and the agricultural water supply increased, regardless of the climate change scenarios. By simulating the reservoir water storage considering the instream flow post completion of the embankment raising project, it was found that water shortage in the reservoir in the future is not likely to occur when it is supplied with an appropriate instream flow. The range of instream flow tends to decrease over time under RCP 8.5, in which the greenhouse gas reduction policy was not executed, and the restoration of reservoir storage was lower in this scenario than in RCP 4.5, in which greenhouse gas reduction policy was executed.

• Journal of Korean Foot and Ankle Society
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• v.21 no.3
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• pp.93-97
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• 2017

Purpose: The aim of this study was to evaluate the radiological and clinical outcomes of scarf osteotomy for hallux valgus (HV) deformity in elderly patient with osteoporosis. Materials and Methods: A total of 58 elderly patients (mean age, 72.6 years) underwent scarf osteotomy for HV deformity between 2008 and 2015. The mean follow-up period was 24.4 months. Of the 58 patients, 42 were diagnosed with osteoporosis and 16 were diagnosed as normal. The radiological and clinical outcomes were assessed preoperatively, postoperatively, and at final follow-up, including HV angle, intermetatarsal (IM) angle, American Orthopaedic Foot and Ankle Society (AOFAS) score, patient satisfaction, visual analogue scale (VAS), and complication. Results: There was no significant difference in HV angle and IM angle between the osteoporosis group and normal bone mineral densitometry group at all time points, preoperative, postoperative, and final follow-up. Moreover, there was no statistically significant difference between the two groups with respect to the AOFAS score and VAS evaluations. In the osteoporosis group, the mean HV angle improved from $36.7^{\circ}$ preoperatively to $11.3^{\circ}$ at the time of final follow-up, and the mean IM angle improved from $13.2^{\circ}$ to $5.7^{\circ}$. The mean AOFAS score improved from 52.6 preoperatively to 89.1 at the time of final follow-up. With respect to satisfaction, 83.4% of patients were very satisfied or satisfied. There were no serious complications, and all cases showed complete union at the osteotomy site. Conclusion: We believed that scarf osteotomy is a safe, effective procedure for the correction of elderly patients with osteoporosis.

• Smart Structures and Systems
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• v.19 no.2
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• pp.115-126
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• 2017

In this paper, size dependent bending and free flexural vibration behaviors of functionally graded (FG) nanobeams are investigated using a nonlocal quasi-3D theory in which both shear deformation and thickness stretching effects are introduced. The nonlocal elastic behavior is described by the differential constitutive model of Eringen, which enables the present model to become effective in the analysis and design of nanostructures. The present theory incorporates the length scale parameter (nonlocal parameter) which can capture the small scale effect, and furthermore accounts for both shear deformation and thickness stretching effects by virtue of a hyperbolic variation of all displacements through the thickness without using shear correction factor. The material properties of FG nanobeams are assumed to vary through the thickness according to a power law. The neutral surface position for such FG nanobeams is determined and the present theory based on exact neutral surface position is employed here. The governing equations are derived using the principal of minimum total potential energy. The effects of nonlocal parameter, aspect ratio and various material compositions on the static and dynamic responses of the FG nanobeam are discussed in detail. A detailed numerical study is carried out to examine the effect of material gradient index, the nonlocal parameter, the beam aspect ratio on the global response of the FG nanobeam. These findings are important in mechanical design considerations of devices that use carbon nanotubes.

• The korean journal of orthodontics
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• v.36 no.5
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• pp.388-396
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• 2006

Treatment of skeletal Class III malocclusion with mini-implant anchorage is discussed in relation to vertical control of the maxillary posterior dentoalveolar region and horizontal control of mandibular anterior teeth. A midpalatal mini-implant provided anchorage for intruding the maxillary posterior teeth. Mandibular mini-Implant implants were used to bring about labioversion of mandibular anterior teeth. After mandibular setback surgery, improvement of the facial profile was obtained both horizontally and vertically, Total treatment time was 11 months. Stable occlusion was maintained after 18 months of retention, The effectiveness and efficacy of mini-implants for the treatment of skeletal Class III malocclusion are also discussed.