• Fire Science and Engineering
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• v.27 no.6
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• pp.1-7
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• 2013

In this study, the effects of various disk shapes of hydrant on the pressure drop are experimentally and numerically analyzed. The test methods for measuring pressure drop of hydrant are comply with standard of Underwriters Laboratory (UL). The hydrant as used in this study has one inlet, diameter 150 mm, and three outlet, 114.3 mm diameter for one outlet and 63.5 mm diameter for the others. The pressure of the hydrant are measured in the range 760 L/min~2,270 L/min for 63.5 mm outlet and 3,030 L/min~6,060 L/min for 114.3 mm outlet. Also, the numerical results of pressure drop are compared with the experiments to verify the accuracy and to analyze the of various valve shape of hydrant on the pressure drop. The engineering parameters, flow coefficients, are reduced from 181.57 to 136.35 ($L/min/kPa^{0.5}$) with inclined angle of disk from $0^{\circ}$ to $45^{\circ}$. These results are able to practical use for design hydrant to minimize pressure drop.

• The korean journal of orthodontics
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• v.37 no.2 s.121
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• pp.89-97
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• 2007

Objective: The purpose of this study was to measure the insertion torque of orthodontic miniscrews regarding changes in their shape, diameter, and length. Methods: Torque values were measured during continuous insertion of the miniscrews into solid rigid polyurethane foam, using a torque tester of driving motor type with a regular speed of 3 rpm. Orthodontic miniscrews (Biomaterials Korea, Seoul, Korea) of cylindrical type and taper type were used. Results: Increasing the length and diameter of the miniscrews increased the maximum insertion torque value in both cylindrical and taper type screws. Insertion torque was increased at the incomplete head of the cylindrical type screw, and at the tapered part of the taper type screw. The insertion torque value of miniscrews was influenced most by diameter, then shape and length. As a result, it was shown that the diameter of the screw had the most influence on insertion torque, and the taper type screw had a higher torque value than the cylindrical type screw. Conclusion: Therefore, a large diameter or taper type screw are adequate for areas of thin cortical bone with a large interdental space, and a small diameter or cylindrical type screw are adequate in the mandibular molar area or the midpalatal area having thick cortical bone.

• Journal of the Korean Institute of Landscape Architecture
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• v.26 no.4
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• pp.82-94
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• 1999

According to Korean's geographical features of Taek Li Ji, the best location for human settlements is on the vicinity of a stream among a stream, an river and a sea, and not far from a ridge. The researcher chose one of best village which is called Yougokmaeul in Bonghwa-Gun, Kyungsang-Do. This village was created a gathering village with the same surname, can be translated as a hen and the front mountain can be seen as a rooster in the view of the shape of geographical features. As it were, the shape of this village and the cultivated land seems to be an egg inside a nest of a parent's chicken in the respect of the analogy of the theory of P'ungsuchiri which is known as Feng Shui in China and geomancy in the western world, and to effect the defensive psychology of the living environment in the terrain inland. This village is the studying place, Suckchunjungsa as the lecturing and studying place for their following students within the Chunghadonchun, the studying Yougok village, and even the ritual place performing ancestral sacrifices and the first incoming ancestor's graves in the same geographical system. The house site of the first incoming resident is surrounded the countian and is located in the front of Backsulryount which is the main mountain through Moonsu-san in the branch mountain of Korean's mountain system. Backsulryoung which is to be seen as the white peak, is symbolized the head of a hen which is to relate to a mysterious turtle in the view of P'ungsuchiri. And the pavilion which is called Chungamjung is sited on the rock of a shape of turtle which is symbolized to live longer. In the section of the mountain and water, Lee Jung Hwan mentioned a living place near the mountain stream is the best residential area and a landscape which is composed by a stream between mountains make a pleasure spirit and a bright feeling and make a refined person. If one can reach in the graceful mountain make a pleasure split and a bright feeling and make a refined person. If one can reach in the graceful mountain half day away, this kind of place must be a best living residential area to live. But this village was structured all in one place. And one of the ideas tangibly reflected in traditional Korean society's view of life and nature is the seclusion based on the Taoism. This kind of a dreamy thoughts make a dream to keep the paradise in our ancestors' mind. This kind of utopia is Chunghadonchun which is structured 5 aspects from the utopian gate near the Samgaesuewon to the village. These 5aspects is expressed by some Confucian thoughts as a small cosmos individually. On the third aspects which is the center among these aspects, the Suckchunjungsa which was made a seclusion place to devoting himself to his studies with refined tastes. The word of Jiju-am, Gangpung-dae, Jaewol-dae and Biryoung-pock are all expressed to cultivate one's moral character and to seek the truth by the Confucius'theory through the nature.

• Korean Journal of Heritage: History & Science
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• v.42 no.3
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• pp.132-153
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• 2009

A lotus flower pattern of the shape of straight and pointed petals has the forms whose lotus flowers are pointed, and is one of the representative forms of lotus flower pattern of Baekjae along with a round and a triangle protruded style. This style of lotus flower pattern was applied to roof-end tiles, halos of Buddhist images, containers of Buddha's bones, head supports, etc. from the Hanseong period to the Sabi period of Baekjae. However most of lotus flower patterns that remain today were used for the tiles of the Sabi period. Many of them were produced under the influence of the Northern Dynasties and the Southern Dynasties of China, and of Goryeo, which implies the active cultural exchange of Baekjae at that time. Among the present lotus flower patterns of the shape of the straight and pointed petals, that of the earliest time is from Gyeongdang district of Poongnab mud castle and belongs to the mid-fifth century. However there is a higher chance that the gradual subsequent excavation and research will find some tiles of the earlier period and other styles can also be unearthed.

• Conservation Science in Museum
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• v.30
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• pp.1-22
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• 2023

This study aims to document the conservation treatment of the fine-hemp official headgear housed by the National Museum of Korea, and to reconsider its existing name following the restoration of the original form of the damaged cultural heritage asset. The headgear consists of a single inner frame with a vertical line at the front, a single outer frame surrounding the inner frame, and a double-layered headband that spans the circumference of the wearer's head and joins the inner and the outer frames. This study applied a conservation treatment to the men's undyed hemp headgear of the Joseon Dynasty in order to remove contaminants and foreign substances on the surface and repair the partially deteriorated and damaged fabric, thereby restoring and stabilizing the original shape and preparing it for exhibitions. The hemp headgear was sewed both by hand and with a sewing machine. Although its overall composition and style are similar to the same type of official headgear from the Joseon Dynasty, the use of a sewing machine supports the assumption that it was produced in the early 1900s. This study identified similarities between the overall composition and shape of the fully-preserved hemp official headgear and those of the jangbogwan, a type of men's official headgear worn by Confucian scholars as part of their everyday attire, and compared it with the shape of jangbogwan seen in documentary records, illustrations, prior research, and portraits from the Joseon Dynasty, as well as with the characteristics of extant jangbowan artifacts, eventually concluding that it is appropriate to classify and name the headgear as a jangbogwan.

• Korean Journal of Heritage: History & Science
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• v.51 no.2
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• pp.4-21
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• 2018

This paper reviewed the legitimacy of the name of those sixteen pieces of hat artifacts known in Korean as pyeongjeongmo and currently housed by the National Palace Museum. This was undertaken in order to rectify the error of calling them pyeongjeongmo. Also, the paper suggested pyeongjeongmo's production method to apply representation of the artifacts or production of Joseon officials' hats as representation of ritual costumes in the royal court. The name pyeongjeongmo originated from pyeongjeonggeon. Gyeongguk Daejeon recorded that noksas wore yugak-pyeongjeonggeon and seoris wore mugak-pyeongjeonggeon, but the pyeongjeongmo artifacts housed in the National Palace Museum have been found irrelevant to those pyeongjeonggeons put on by both noksas and seoris. Rather, they has been confirmed as corresponding to dugeon or jogeon worn by byeolgams or suboks who served at the palace of the crown prince or princess. Through the investigation of the artifacts, the researchers could find out the tailoring and sewing methods, the finished look, and the folding manner of pyeongjeonggeon. Although the structure of pyeongjeonggeon was generally consistent, the frontal look was slightly different depending on the folding manner, resulting in three distinguished types of pyeongjeonggeon. Regardless, the pyeongjeongmo was made with one piece of fabric by a flat tailoring and folding method to create a three-dimensional hat. The finished shape appeared low in the front and high in the back side structure. The head girth was 55~59 cm, and the height was 19.4~21.5 cm. To make it with one piece of fabric, the head girth part was tailored in the same direction as the strands. Based on the artifact Changdeok 23820, this paper has also suggested a finished reproduction through the processes of preparing the materials, mounting, making the center ornaments, sewing and folding. The tailoring was completed with black silk fabric which was cut in a unique shape designed in advance, and hemp fabric which was mounted to the former. The top part of the head was finished with black threads, and the center line at the back was fixed with decolored cotton threads by blanket stitches with 3.5~4 cm intervals. Bamboo strands were inserted in the inside of the front-folded part, which then was fixed by patterned stitches with white cotton thread. At the back, a small bamboo clasp was attached so that one can lock it to the headband and prevent it from falling off.

• The Korean Journal of Ecology
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• v.17 no.3
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• pp.355-366
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• 1994

The purpose of this study was to investigate the changes of water quality and the patterns of self-purification with season in Gokneung stream. The vegetation in the ecosystem around Gokneung stream was dominated by Quercus species. In the physicochemical analysis based on the contents of DO, BOD, conductivity and total phosphorus, the upstream seemed to have been polluted, but the downstream was self-purified. In biological investigation by bentic macroinvertebrates, the result was similar to that in the physicochemical analysis. The self-purification constant based on BOD of the upstream, 1.013, was the highest. In the self-purification constants with month, that of September was 0.995 and that of January was 0.272. These results indicated that the self purification capacities of spring and autumn were larger than those of winter and summer in Gokneung stream.

• Progress in Medical Physics
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• v.26 no.3
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• pp.168-177
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• 2015

For evaluating the treatment planning accurately, the quality assurance for treatment planning is recommended when patients were treated with IMRT which is complex and delicate. To realize this purpose, treatment plan quality assurance software can be used to verify the delivered dose accurately before and after of treatment. The purpose of this study is to evaluate the accuracy of treatment plan quality assurance software for each IMRT plan according to MLC DLG (dosimetric leaf gap). Novalis Tx with a built-in HD120 MLC was used in this study to acquire the MLC dynalog file be imported in MobiusFx. To establish IMRT plan, Eclipse RTP system was used and target and organ structures (multi-target, mock prostate, mock head/neck, C-shape case) were contoured in I'mRT phantom. To verify the difference of dose distribution according to DLG, MLC dynalog files were imported to MobiusFx software and changed the DLG (0.5, 0.7, 1.0, 1.3, 1.6 mm) values in MobiusFx. For evaluation dose, dose distribution was evaluated by using 3D gamma index for the gamma criteria 3% and distance to agreement 3 mm, and the point dose was acquired by using the CC13 ionization chamber in isocenter of I'mRT phantom. In the result for point dose, the mock head/neck and multi-target had difference about 4% and 3% in DLG 0.5 and 0.7 mm respectively, and the other DLGs had difference less than 3%. The gamma index passing-rate of mock head/neck were below 81% for PTV and cord, and multi-target were below 30% for center and superior target in DLGs 0.5, 0.7 mm, however, inferior target of multi-target case and parotid of mock head/neck case had 100.0% passing rate in all DLGs. The point dose of mock prostate showed difference below 3.0% in all DLGs, however, the passing rate of PTV were below 95% in 0.5, 0.7 mm DLGs, and the other DLGs were above 98%. The rectum and bladder had 100.0% passing rate in all DLGs. As the difference of point dose in C-shape were 3~9% except for 1.3 mm DLG, the passing rate of PTV in 1.0 1.3 mm were 96.7, 93.0% respectively. However, passing rate of the other DLGs were below 86% and core was 100.0% passing rate in all DLGs. In this study, we verified that the accuracy of treatment planning QA system can be affected by DLG values. For precise quality assurance for treatment technique using the MLC motion like IMRT and VMAT, we should use appropriate DLG value in linear accelerator and RTP system.

• The Korean Journal of Nuclear Medicine Technology
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• v.17 no.2
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• pp.84-89
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• 2013

Purpose: Patients' movement during long image acquisition time for the fusion image of PET-CT (Positron Emission Tomography-Computed Tomography) results in unconformity, and greatly affects the quality of the image and diagnosis. The arm support fixtures provided by medical device companies are not manufactured considering the convenience and safety of the patients; the arm and head movements (horizontal and vertical) during PET/CT scan cause defects in the brain fundus images and often require retaking. Therefore, this study aims to develop patient-compensation device that would minimize the head and arm movements during PET/CT scan, providing comfort and safety, and to reduce retaking. Materials and Methods: From June to July 2012, 20 patients who had no movement-related problems and another 20 patients who had difficulties in raising arms due to shoulder pain were recruited among the ones who visited nuclear medicine department for PET Torso scan. By using Patient Holding System (PHS), different range of motion (ROM) in the arm ($25^{\circ}$, $27^{\circ}$, $29^{\circ}$, $31^{\circ}$, $33^{\circ}$, $35^{\circ}$) was applied to find the most comfortable angle and posture. The manufacturing company was investigated for the permeability of the support material, and the comfort level of applying bands (velcro type) to fix the patient's head and arms was evaluated. To find out the retake frequency due to movements, the amount of retake cases pre/post patient-compensation were analyzed using the PET Torso scan data collected between January to December 2012. Results: Among the patients without movement disorder, 18 answered that PHS and $29^{\circ}$ arm ROM were the most comfortable, and 2 answered $27^{\circ}$ and $31^{\circ}$, respectively. Among the patients with shoulder pain, 15 picked $31^{\circ}$ as the most comfortable angle, 2 picked $33^{\circ}$, and 3 picked $35^{\circ}$. For this study, the handle was manufactured to be adjustable for vertical movements. The material permeability of the patient-compensation device has been verified, and PHS and the compensation device were band-fixed (velcro type) to prevent device movements. A furrow was cut for head fixation to minimize the head and neck movements, fixing bands were attached for the head, wrist, forearm, and upper arm to limit movements. The retake frequency of PET Torso scan due to patient movements was 11.06% (191 cases/1,808 patients) before using the movement control device, and 2.65% (48 cases/1,732 patients) after using the device; 8.41% of the frequency was reduced. Conclusion: Recent change and innovation in the medical environment are making expensive medical image scans, and providing differentiated services for the customers is essential. To secure patient comfort and safety during PET/CT scans, ergonomic patient-compensation devices need to be provided. Therefore, this study manufactured a patientcompensation device with vertically adjustable ergonomic ROM according to the patient's body shape and condition during PET Torso scan. The defects in the basal ganglia images due to arm movements were reduced, and retaking was decreased.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.1
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• pp.61-69
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• 2008

Purpose: Micro-pinhole SPECT system with conventional multiple-head gamma cameras has the advantage of high magnification factor for imaging of rodents. However, several geometric factors should be calibrated to obtain the SPECT image with good image quality. We developed a simplified geometric calibration method for rotating triple-head pinhole SPECT system and assessed the effects of the calibration using several phantom and rodent imaging studies. Materials and Methods: Trionix Triad XLT9 triple-head SPECT scanner with 1.0 mm pinhole apertures were used for the experiments. Approximately centered point source was scanned to track the angle-dependent positioning errors. The centroid of point source was determined by the center of mass calculation. Axially departed two point sources were scanned to calibrate radius of rotation from pinhole to center of rotation. To verify the improvements by the geometric calibration, we compared the spatial resolution of the reconstructed image of Tc-99m point source with and without the calibration. SPECT image of micro performance phantom with hot rod inserts was acquired and several animal imaging studies were performed. Results: Exact sphere shape of the point source was obtained by applying the calibration and axial resolution was improved. Lesion detectibility and image quality was also much improved by the calibration in the phantom and animal studies. Conclusion: Serious degradation of micro-pinhole SPECT images due to the geometric errors could be corrected using a simplified calibration method using only one or two point sources.