• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.2
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• pp.349-353
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• 2016

The purpose of this study was to investigate possible age differences in the attenuation of acceleration in the upper body (from pelvis through shoulder to head) during fast walking. Thirty young and 29 elderly subjects participated in this study. Wireless acceleration sensors were attached on head, shoulder, and pelvis. Subjects performed two trials of fast walking on a treadmill, where the fast speed was defined as 1.5 times of the comfortable speed. Root-mean-squared (RMS) accelerations of each axis were compared with age group and sensor position as independent factors. In the AP direction, the pelvis acceleration was greater in the young and the shoulder-to-head attenuation was also greater in the young (p<0.001), so that the head acceleration was comparable between age groups (p=0.581). In the ML direction, the pelvis acceleration was greater in the young and also the pelvis-to-shoulder attenuation was greater in the young (p<0.001), so that the head acceleration was greater in the elderly group (p<0.001). Insufficient attenuation ML acceleration in the elderly resulting in the greater acceleration in the head may deteriorate the balance control which utilize feedback signals from the sensory organs in head, e.g., vestibular and visual systems.

• Nuclear Engineering and Technology
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• v.53 no.3
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• pp.763-775
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• 2021

The thermal hydraulic performances of Steam Generator (SG) under both steady and transient operation conditions are of great importance for the safety and economy in nuclear power plants. In this paper, based on our self-developed SG thermal hydraulic analysis code STAF (Steam-generator Thermalhydraulic Analysis code based on Fluent), an improved new version STAF-CT (fully Coupling and Transient) is developed and introduced. Compared with original STAF, the new version code STAF-CT has two main functional improvements including "Transient" and "Fully Three Dimensional Coupling" features. In STAF-CT, a three dimensional energy transferring module is established which can achieve energy exchange computing function at the corresponding position between two sides of SG. The STAF-CT is validated against the international benchmark experiment data and the results show great agreement. Then the U-shaped SG in AP1000 nuclear power plant is modeled and simulated using STAF-CT. The results show that three dimensional flow fields in the primary side make significant effect on the energy source distribution between two sides. The development of code STAF-CT in this paper can provide an effective method for further SG high fidelity research in the nuclear reactor system.

• Nuclear Engineering and Technology
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• v.56 no.1
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• pp.9-18
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• 2024

In-vessel retention through external reactor vessel cooling (IVR-ERVC) is a severe accident management (SAM) strategy that has been adopted and used in many nuclear reactors such as AP1000, APR1400, and light water reactor etc. Some reactor accidents have raised concerns about nuclear reactors among residents, leading to a decrease in residents' acceptability and many studies on SAM are being conducted. Experiments on IVR-ERVC are almost impossible due to its specificity, so fluid characteristics are analyzed through BALI experiments with similar condition. In this study, computational fluid dynamics (CFD) via Reynolds-averaged Navier-Stokes (RANS) and large eddy simulation (LES) for BALI experiments were performed. Steady-state CFD analysis was performed on three turbulence models, and SST k-ω model was in good agreement with the experimental measurement temperature within the maximum error range of 1.9%. LES CFD analysis was performed based on the RANS analysis results and it was confirmed that the temperature and wall heat flux for depth was consistent within an error range of 1.0% with BALI experiment. The LES CFD analysis results were compared with those of the Lagrangian-based solver. LES matched the temperature distribution better than SOPHIA, but SOPHIA calculated the position of boundary between stratified layer and convective layer more accurately. On the other hand, Lagrangian-based solver predicted several small eddy behaviors of the convective layer and LES predicted large vortex behavior. The vibration characteristics near the cooling part of the BALI experimental device were confirmed through Fast Fourier Transform (FFT) investigation. It was found that the power spectral density for pressure at least 10 times higher near the side cooling than near the top cooling.

• Journal of the Korean Society of Radiology
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• v.10 no.2
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• pp.101-107
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• 2016

It was performed in this study to provide basic information on production of accurate gonadal shield by measuring pelvic indicators of TDP SD ISP IAD 1CDP and 2CDP. when pelvis ap and hip ap examination was taken, there is no exact position of the reference point of the shield and anatomically more difficult to shield gonad in the case of female infants than male. Results analyzed by height in 70~80 and 110~120 were approximately 30mm 13mm 19mm 20mm 2mm and 7mm difference in TDP SD ISP IAD 1CDP and 2CDP respectively. This value was statistically significant (P<0.05). Results analyzed by age of 2~3 and 6~7 were different on SD ISP IAD and 2CDP by 17mm 10mm 12mm 16mm respectively. it was also statistically significant. However 1CDP was not statistically significant(P>0.05). the difference was nearly about 1mm. Analysis of results by weight of less than 10 and more than 20 showed difference on TDP SD ISP IAD 1CDP and 2CDP by 28mm 14mm 11mm 20mm 3mm and 8mm. it was statistically significant (P<0.05). From the above results, female infants pelvic indicator measurement can be used as reference value for shielding production and especially IAD can present a reference point on the shielding position. Pelvis indicators of female infant has a close correlation. In addition, as it is showen in the statistical difference analysis to have an accurate ovarian shield, gonad shield would be produced and used by height, age and weight.

• The Journal of Korean Society for Radiation Therapy
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• v.35
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• pp.7-13
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• 2023

Purpose: In this study, we evaluated the effect of using a customized bolus on dose delivery in the treatment plan when cervical cancer protruded out of the body along with the uterus and evaluated reproducibility in patient set-up. Materials & Methods: The treatment plan used the Eclipse Treatment Planning System (Version 15.5.0, Varian, USA) and the treatment machine was VitalBeam (Varian Medical Systems, USA). The radiotherapy technique used 6 MV energy in the AP/PA direction with 3D-CRT. The prescribed dose is 1.8 Gy/fx and the total dose is 50.4 Gy/28 fx. Semiflex TM31010 (PTW, Germany) was used as the ion chamber, and the dose distribution was analyzed and evaluated by comparing the planned and measured dose according to each position movement and the tumor center dose. The first measurement was performed at the center by applying a customized bolus to the phantom, and the measurement was performed while moving in the range of -2 cm to +2 cm in the X, Y, and Z directions from the center assuming a positional error. It was measured at intervals of 0.5 cm, the Y-axis direction was measured up to ±3 cm, and the situation in which Bolus was set-up incorrectly was also measured. The measured doses were compared based on doses corrected to CT Hounsfield Unit (HU) 240 of silicon instead of the phantom's air cavity. Result: The treatment dose distribution was uniform when the customized bolus was used, and there was no significant difference between the prescribed dose and the actual measured value even when positional errors occurred. It was confirmed that the existing sheet-type bolus is difficult to compensate for irregularly shaped tumors protruding outside the body, but customized Bolus is found to be useful in delivering treatment doses uniformly.

• Journal of Yeungnam Medical Science
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• v.21 no.1
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• pp.40-50
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• 2004

Background: This study was conducted to analyze the height and width of the pedicle of the upper and lower levels on the concave and the convex sides. In addition, we checked for the appropriate pedicle screw size which could be screwed in without complications. Materials and Methods: Taking a simple AP radiography in a standing position, 99 vertebrae on the major curve with the possibility of 3-D reconstruction were analyzed after checking the CT in a supine position of 22 idiopathic scoliosis. We measured Cobb's angle from a simple radiograph, and measured the size of the isthmus by the Inner Space 3-D Editor after 3-D reconstruction with the Inner Space 3-D program in the DICOM file transformed from CT image. We then analyzed the size of pedicles of the upper and lower levels on the concave and the convex sides by measuring the height and width of the pedicle. Results: All pedicles on the concave side were smaller than those on the convex side. Their size increased as the measurement moved from the upper to lower vertebra, except for the upper thoracic vertebra. When the width of the pedicle through 3-D reconstruction was compared with the narrowest width of the pedicle measured by using CT, the width of the pedicles through 3-D reconstruction was statistically smaller (P<0.01). Most of the pedicles were tear-drop or kidney shaped rather than cylindrical. Conclusion: These results suggest that the use of the coronal plane through 3-D reconstruction would be necessary for an accurate measurement of the size of the pedicle. It is important to pay careful attention to the screw size and the screwing method considering the pedicle shape through 3-D reconstruction.

• Journal of radiological science and technology
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• v.40 no.4
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• pp.543-548
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• 2017

The aim of this study was to evaluate anteroposterior oblique(RPO, LPO) and posteroanterior oblique(LAO, RAO) projections of the cervical spine, at various kVp and mA s increments, in order to compare thyroid surface dose. Using Rando phantom, dosimeter was attached to the Cervical spine 4~5 to measure the surface dose in the same thyroid position. As a result, the surface dose was $595.08{\pm}215.01{\mu}Gy$ for anteroposterior oblique(RPO, LPO) projections and $64.21{\pm}33.49{\mu}Gy$ for posteroanterior oblique(LAO, RAO) projections by changing kVp increment. The surface dose was $445.20{\pm}230.90{\mu}Gy$ for anteroposterior oblique(RPO, LPO) projections and $44.51{\pm}22.77{\mu}Gy$ for posteroanterior oblique(LAO, RAO) projections by changing mAs increment. The posteroanterior oblique method could reduce about 90% the surface dose than the anteroposterior oblique method. There were statistically significant differences among the examinations(p<0.001). Change the direction of position to reduce the surface dose at oblique projection of cervical spine. Therefore, we consider posteroanterior oblique projections than anteroposterior oblique projections of cervical spine examination in other to reduce patient surface dose.

• Journal of radiological science and technology
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• v.31 no.2
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• pp.109-114
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• 2008

There is a standard shoulder oblique method (Grashey method) available to view the shoulder joint. This method projects AP view of the shoulder joint so that the Humerus head's subuxation or joint degeneration can be easily visualized. However, in this view, the patients, with supine or sitting or erect position, have to keep their body obliquely. Whereas, the patients who are not well or operated, usually feel very uncomfortable to keep their body in this position and hence, we need other persons' help and much efforts will be needed to get the good quality shoulder joint view. Therefore, we thought of examining a method which shows the joint well by angling the tube to Medio-Lateral direction and without keeping the patients' one side upward in supine position. For this study, total 15 subjects with no history of neurological or psychiatric illness, were recruited for examinations. They consisted of 9 males and 6 females. Statistic group analysis was performed with ANOVA test. Scores of the evaluation of the experts were $1.10{\pm}0.54$ at $25^{\circ}$, $2.50{\pm}0.50$ at 30^{\circ}$, $2.85{\pm}0.36$ at $35^{\circ}$ and $2.33{\pm}0.47$ at $40^{\circ}$, respectively, and they were significant(p<0.05, Table 1). Joint space of the Humerus head and Scapula were well distinguished at $35^{\circ}$, $30^{\circ}$ and $40^{\circ}$ with the almost same score. However, the degree of distortion at $40^{\circ}$ was more severe than that at $30^{\circ}$. Ultimately, $30-35^{\circ}$ views were shown to yield good quality shoulder oblique images. In conclusion, this method may be very useful for the patients who are uncomfortable and for the emergency patients. In order to get similar or comparable view, the same X-tube angle is recommended to be used before and after the operation. Therefore, we hope that this new angled method seems to be efficient.

• Progress in Medical Physics
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• v.20 no.1
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• pp.1-6
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• 2009

For HDR intracavitary brachytherapy with ovoids and a tandem, we compared the dose discrepancy of treatment plans using two different Ir-192 sources (microSelectron, Varian) and generated on two different treatment planning systems (PLATO, BrachyVision). The treatment plans of ten patient treated from Oct. 2007 to Jan. 2008 were selected for these comparisons. For the comparison of dose calculation using different sources, the average discrepancies were $-0.91{\pm}0.09%$, $-0.27{\pm}0.07%$, $0.22{\pm}0.39%$, and $0.88{\pm}0.37%$ in total treatment time and at B-point and ICRU bladder and rectum reference point, respectively. Comparing the two systems, the average dose discrepancies between treatment planning programs were $-0.22{\pm}0.42%$, $-0.25{\pm}0.29%$, $-0.23{\pm}0.63%$, and $-0.17{\pm}0.76%$, and the average dose discrepancies between positioning methods (PLATO with film and BrachyVision with digitial image) were $-0.61{\pm}0.59%$, $-0.77{\pm}0.45%$, $-0.72{\pm}1.70%$, and $0.35{\pm}2.82%$ at A-point, B-point, and ICRU bladder and rectum reference points, respectively. The rectal dose discrepancies between two systems were reached 5.87%. The difference in the dwell position expected by each TPS are mainly affected by the differences in the positioning method in TPSs and have an effect on dose calculations of rectal and bladder located in AP direction.

• Journal of Korean Academy of Nursing
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• v.23 no.1
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• pp.56-67
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• 1993

The purpose of this study was to compare the circumference and skinfold thickness of upper and lower limb and the leg strength of the casted limb with those of the normal limb after removal of a leg cast. The subjects for the study were orthopedic patients who had had long and short leg casts or splints due to tibial, fibulal, metatarsal, calcaneus fracture or ankle sprains. The subjects were divided into two groups, those who had the cast on for less than 40 days and those for over 41 days. Circumference and skinfold thickness of the upper and lower limb on the side on which the cast was ap-plied were compared with those of the contralateral side after removal of the cast. Circumference and skinfold thickness of the upper and lower limb, and leg strength for those in a cast for under 40 days were compared with those of over 41 days for both the side to which cast was applied and the contralateral side. Measurements were made after removal of the cast. Skinfold thickness was measured by fat caliper, circumference was measured by tape and lower extremity strength was determined with flat foot pressing on an electronic digital health meter in the sitting position. The results can be summarized as follows : 1. The circumference of the upper and lower leg on the side on which the cast was applied, when measured after the cast was removed, were significantly less than those of the normal side, 93.88%, 93.11% each. 2. Skinfold thickness of the quadriceps and gastrocnemius on the side on which the cast was applied were significantly less than those of the normal side when measured after removal of the cast, 85.98%, 82.85% respectively. 3. Leg strength on the side where the cast was applied was significantly 1ss than that on the normal side, 60.20%. 4. There was no difference in the circumference of upper and lower limbs, skinfold thickness or leg strength on the side where the cast was applied between the group which had the cast applied for under 40 days and the group that had it applied for over 41 days. 5. The circumference of the upper arm and lower leg on the normal side for the group that had the cast applied for over 41 days was significantly greater than the group that had the cast application for under 40 days. T ere was no difference between the two groups in the circumference of the forearm and upper leg, skinfold thickness and leg strength in the normal side. From these results, it may be concluded that muscle atrophy was apparent in the casted limb compared to the normal limb, and the circumference of the upper arm and lower leg, and leg strength on the normal side increased after removal of the cast in the group which had the cast on for more than 41 days.