• The Korean Journal of Nuclear Medicine Technology
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• v.16 no.2
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• pp.120-125
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• 2012

Purpose : The purpose of this study was to compare count between Chang's method and CT-based attenuation correction (AC-CT) among the attenuation correction (AC) methods for non-attenuation correction (AC-non) images of Brain SPECT (Single Photon Emission Computed Tomography). Materials and Methods : We injected $^{99m}Tc$ 37Mbq in a Hoffman 3D phantom filled with distilled water in the phantom study, and injected intravenously $^{99m}Tc$-HMPAO 740Mbq in a normal volunteer in the patient study, and then obtained Brain SPECT images with Symbia T6 of Siemens and conducted quantitative brain analysis. Transverse images to which each method was applied were rebuilt at the same position, and 6 regions of interest (ROI) were drawn on each of Slice No. 10, 20 and 30 and then the counts of AC-non, AC-CT and Chang's method were compared. Results : The mean counts of AC-non, AC-CT and Chang's method were $4606.8{\pm}511.3$, $16794.6{\pm}2429.4$, and $8752.6{\pm}896.5$, respectively, in the phantom study and $5460.8{\pm}519.6$, $15320{\pm}1171.6$ and $12795{\pm}1422.1$, respectively, in the patient study. In the phantom study, the ratio of AC-CT to AC-non was 3.70 and the ratio of Chang's method to AC-non was 1.92, and in the patient study, they were 2.85 and 2.38, respectively. Conclusion : From this study, we found that AC-CT makes higher AC than Chang's method. In addition, when Chang's method was used, AC in the patient study was higher than that in the phantom study. These results need to be considered also in other examinations.

• Journal of the Korean Society of Radiology
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• v.12 no.1
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• pp.39-46
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• 2018

The purpose of this study was to determine suitable angle of Tibia-foot and the X-ray tube for scaphoid in foot X-ray examination. A total of twenty patients(mean age $32.12{\pm}years)$ are participated in this study. In the positions of Foot AP, internal and external oblique, tibia-foot angle was defined as $90^{\circ}$ and $135^{\circ}$, and x-ray tube angle was defined as $0^{\circ}$, $5^{\circ}$, $10^{\circ}$, $15^{\circ}$ and $20^{\circ}$ respectively. The image quality was evaluated with blind test yielding scores ranging from 0 to 5 by the evaluation team consisted of 2 radiogical technologists, 2 radiologists, and 2 orthopedic surgeons. In case of Foot AP position, the degree of overlap between cuneiform and navicular was 3% and the blind test result was 4.89 at tibia-foot angle of $90^{\circ}$ and $15^{\circ}$ X-ray tube angle. When the tibia-foot angle is $135^{\circ}$, the degree of overlap was 5%, also the blind test result was 4.30 at $15^{\circ}$ X-ray tube angle. The degree of overlap and blind test result were 30% and 3.75 respectively at $0^{\circ}$ X-ray tube angle. In case of internal oblique position, at tibia-foot angle of $90^{\circ}$ and $0^{\circ}$ X-ray tube angle, the degree of overlap was 4% and the blind test result was 4.70. The 5% overlapping and highest score as 4.55 were obtained on tibia-foot angle of $135^{\circ}$ and $0^{\circ}$ X-ray tube angle. In case of external oblique position, at tibia-foot angle of $90^{\circ}$ and $15^{\circ}$ X-ray tube angle, the degree of overlap was 4% and the blind test score was 4.85. The 5% overlapping and highest score as 4.75 were obtained on tibia-foot angle of $135^{\circ}$ and $15^{\circ}$ X-ray tube angle. In conclusion, we confirmed suitable angle of tibia-foot and X-ray tube for scaph46oid in foot X-ray examination in this study. These findings will be helpful for us to reading for navicular fracture.

• Journal of the Korean earth science society
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• v.32 no.3
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• pp.276-293
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• 2011

In this study a modeling system consisting of Weather Research and Forecasting (WRF), Sparse Matrix Operator Kernel Emissions (SMOKE), the Community Multiscale Air Quality (CMAQ) model, and the CMAQ-Model of Aerosol Dynamics, Reaction, Ionization, and Dissolution (MADRID) model has been applied to estimate enhancements of $PM_{10}$ during Asian dust events in Korea. In particular, 5 experimental formulas were applied to the WRF-SMOKE-CMAQ (MADRID) model to estimate Asian dust emissions from source locations for major Asian dust events in China and Mongolia: the US Environmental Protection Agency (EPA) model, the Goddard Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) model, and the Dust Entrainment and Deposition (DEAD) model, as well as formulas by Park and In (2003), and Wang et al. (2000). According to the weather map, backward trajectory and satellite image analyses, Asian dust is generated by a strong downwind associated with the upper trough from a stagnation wave due to development of the upper jet stream, and transport of Asian dust to Korea shows up behind a surface front related to the cut-off low (known as comma type cloud) in satellite images. In the WRF-SMOKE-CMAQ modeling to estimate the PM10 concentration, Wang et al.'s experimental formula was depicted well in the temporal and spatial distribution of Asian dusts, and the GOCART model was low in mean bias errors and root mean square errors. Also, in the vertical profile analysis of Asian dusts using Wang et al's experimental formula, strong Asian dust with a concentration of more than $800\;{\mu}g/m^3$ for the period of March 31 to April 1, 2007 was transported under the boundary layer (about 1 km high), and weak Asian dust with a concentration of less than $400\;{\mu}g/m^3$ for the period of 16-17 March 2009 was transported above the boundary layer (about 1-3 km high). Furthermore, the difference between the CMAQ model and the CMAQ-MADRID model for the period of March 31 to April 1, 2007, in terms of PM10 concentration, was seen to be large in the East Asia area: the CMAQ-MADRID model showed the concentration to be about $25\;{\mu}g/m^3$ higher than the CMAQ model. In addition, the $PM_{10}$ concentration removed by the cloud liquid phase mechanism within the CMAQ-MADRID model was shown in the maximum $15\;{\mu}g/m^3$ in the Eastern Asia area.

• Journal of The Korean Association For Science Education
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• v.32 no.4
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• pp.775-788
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• 2012

This study was done at a scientific camp sponsored by Nara Women's University Secondary School, Japan. In this school, $10^{th}$ grade students from 4 East Asian countries: Korea, Japan, Taiwan, and Singapore, participated. We made a research on students' perceptions about nuclear energy. Sample populations include 77 students in total, with 12 Korean, 46 Japanese, 9 Taiwanese and 10 Singaporean students. Overall perceptions comparison about nuclear energy shows average values from the order of highest Korea, Taiwan, Singapore, and to lowest, Japan. We implemented a T-test to identify perception differences about nuclear energy, with one group that include 3 countries (Korea, Taiwan and Singapore) and another group that includes all the Japanese students. T-test results of perceptions about nuclear energy shows students from the 3 countries of Korea, Taiwan and Singapore having higher average than Japanese students. (p<.05). Korean average scores regarding overall perceptions about nuclear energy show as the highest in all 4 East Asian countries and also highest in all subcategories. On the contrary in Japan, they have lower and negative perceptions of nuclear energy. In spite of these facts, perceptions of Japanese students about nuclear energy seem lowest and negative mainly because of the recent Fukushima nuclear power plant disaster, caused by the tsunami and its subsequent damages and fears of radiation leaks, etc. This shows that negative information about future disasters and its resulting damages like the Chernobyl nuclear accident could influence more on people's risk perception than general information like nuclear energy-related technologies or the news that the plant is operating normally, etc. Even if the possibility of this kind of accident is very low, just one accident could bring abnormal risks to technology itself. This strong signal makes negative image and strengthens its perceptions to the people. This could bring a stigma about nuclear energy. This study shows that Government's policy about the highest priority for nuclear energy safety is most important. As long as such perception and decision are fixed, we found that it might not be easy to get changed again because they were already fortified and maintained.

• Journal of the Korean Institute of Landscape Architecture
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• v.37 no.3
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• pp.91-104
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• 2009

This paper attempts to look at the identity of the traditional famous sceneries of Jeju Island by investigating the relationship between 'Yeoung Ju-Sipikyung(瀛州十二景)', which are the representative beautiful scenes of Jeju Island, and two paintings 'T'amna-Sipkyungtdo(耽羅十景圖)' and 'T'amna-Sullyokto(耽羅巡歷圖)' by a grasp of the contents and meanings of these two paintings. The following are the results of the study. In the 'T'amna-Sipkyung', which is the origin of today's 12 beautiful sceneries of Jeju Island, Baekrokdam and Youngsil are both symbolic places and the backdrops against which Jeju's myths were formed. Jocheonjin, Seogwijin and Myoungwoljin, located near the seashores, are strategic footholds in protecting the territory of the island and connotatively contain its culture and history. Seongsan Ilchulbong, Sanbangsan, Chwibyeongdam and Cheonjeyeon Pokpo are not only the quintessentially beautiful scenes of Jeju but also belong to 'YeoungJu-Sipikyung'. And 'T'amna-Sullyokto', which describes the Jeju horses and tangerines that were presented to the king as tribute, offers scenic elements with a strong political tone and is related to the five scene of 'T'amna-Sullyokto', showing that 'defense' and 'tribute' are motives in choosing the sceneries of people's daily lives here. Jeju's daily scenes in particular have been continuously transmitted: 'Idyllic lives with the background of a tangerine orchard' are shown in 'Kowon Panggo' and 'Kyullim P'ungak', and Jeju horses grazing on pastures or being ridden in hunting trips are presented in 'Sanjang Kuma' and 'Kyorae Taeryop'. Besides Baekrokdam and Youngsil, which do not belong to Sunyeok(巡歷) corridor of minister Lee Hyoungsang, 'Yeoung Ju-Sipikyung', directly related to 'T'amna-Sipkyung', has six beautiful sceneries: Seongsan of Seongsan Ilchulbong, Baekrokdam of Baekrokmanseol, Younggok of Youngsilgiam, Sanbang of Sanbanggulsa Chwibyeongdam of Yongyeonyabeom and Seogwiso of Seojinnoseong. The image of 'Gosumokma', the tenth landscape of 'Yeoung Ju-Sipikyung', was expressed as it is, through 'Udojeomma' and 'Sanjangguma'. The ten beautiful sceneries of 'T'amna-Sipkyung' were also especially described in 'T'amna-Sullyokto', besides Baekrokdam and Youngsil, which do not belong to Sunyeok corridor. As the places and landscapes emphasized on 'T'amna-Sipkyungto' and 'T'amna-Sullyokto' in common have been transmitted by the politicians and ancestors of Jeju Island, they have become established as today's 'Yeoung Ju-Sipikyung', passing through correction processes. When considering this process of development, 'Yeoung Ju-Sipikyung' are worthy of heritage and traditional landscapes accomplished in a long difficult period based on investigation into beautiful Jeju Island and the love of the island people for their home.

• Journal of the Korean Institute of Landscape Architecture
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• v.41 no.6
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• pp.72-83
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• 2013

This study suggests the necessity of landscaping alternatives for the succession of Takjok(濯足) culture by considering the background and meaning of Takjok's cultural phenomenon shown in old literatures and paintings and its result is as follows. An old idiom, 'Takyoung Takjok(濯纓濯足)' implying a disinterested living attitude from the mundane world and an attitude complying with nature, has been sublimated to 'Takjokjiyu(濯足之遊)' which means living in comfortable retirement through life in seclusion(隱逸). Classical scholars immerse their feet in soft-flowing(柔軟) water for 'Mulailche(物我一體; synchronized with nature)' which is a unified condition with 'Do(道; truth)' and connected to the stage of 'Yu(遊)', a free mental state, and its nature. The cultural phenomenon of Takjok appeared in the inherited landscape paintings in the Joseon dynasty period after the late stage of Koryo. Takjok shown in 'Pal Kyung Shi'(八景詩; poetry singing for the eight scenary) was described as not a transcendent scene, but as a scenery of daily life. Dense forest and water, such as a stream with clean water, rocks, and pine trees shown in Takjok paintings have been symbolized as a seclusion space for classical scholars with higher thinking and their mental states have been more emerged. Mental pleasures called as seclusion and Takjokjiyu have been relatively emphasized in the Takjok paintings of the Joseon Dynasty period contrary to the Chinese Takjok paintings emphasizing Chung Gye(淸溪; clean stream) and Chang Rang(滄浪; high and clean wave) and strongly representing the image of 'Chung Ryu'(淸流; clean flowing water) and the veneration for antiquity. The view of nature described in the Takjok paintings represents the provision of nature as a situation and attitudes of classical scholars and implies a Taoism perspective which describes the 'do' of nature. This view of nature itself remained intact(無爲自然) with the love of mountains and water, showing a side of the zeitgeist and aesthetic consciousness of China and Joseon. The 'Takjokjiyu' of both countries has be interpreted as a symbol of personality development, behavior, life in seclusion, or transcending the mundane world and has also been accepted as a method of summer vacation in the real world. It should be considered that Takjok includes ordinary people's wisdom to resist the hot weather, as well as the classical scholar's ideal and the veneration of antiquity. From this perspective, water space, Takjok rocks, and the use of water based on the environmental supportability should be newly focused as a recreational space and it reminds us that the spirit of Takjok is a classical mental healing method.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.10 no.6
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• pp.69-80
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• 2015

This can be promoted collaboration environment for the system and the system is very important for competitiveness, it is equipped. If so, could work in collaboration with members of the organization to promote collaboration what factors? Organizational collaboration and cooperation of many people working, or worth pursuing common goals by sharing information and processes to improve labor productivity, defined as collaboration. Factors that promote collaboration are shared visions, the organization's principles and rules that reflect the visions, on-line system developments, and communication methods. First, it embodies the vision shared by the more sympathetic members are active and voluntary participation in the activities of the organization can be achieved. Second, the members are aware of all the rules and principles of a united whole is accepted and leads to good performance. In addition, the ability to share sensitive business activities for self-development and also lead to work to make this a regular activity to create a team that can collaborate to help the environment and the atmosphere. Third, a systematic construction of the online collaboration system is made efficient and rapid task. According to Student team and A corporation we knew that Cloud services and social media, low-cost, high-efficiency services could achieve. The introduction of the latest information technology changes, the members of the organization's systems and active participation can take advantage of continuing education must be made. Fourth, the company to inform people both inside and outside of the organization to communicate actively to change the image of the company activities, the creation of corporate performance is very important to figure. Reflects the latest trend to actively use social media to communicate the effort is needed. For development of systematic collaboration promoting model steps to meet the organizational role. First, the Chief Executive Officer to make a firm and clear vision of the organization members to propagate the faith, empathy gives a sense of belonging should be able to have. Second, middle managers, CEO's vision is to systematically propagate the organizers rules and principles to establish a system would create. Third, general operatives internalize the vision of the company stating that the role of outside companies must adhere. The purpose of this study was well done in collaboration organizations promoting factors for strategic alignment model based on the golden circle and collaboration to understand and reflect the latest trends in information technology tools to take advantage of smart work and business know how student teams through case analysis will derive the success factors. This is the foundation for future empirical studies are expected to be present.

• Progress in Medical Physics
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• v.17 no.2
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• pp.89-95
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• 2006

The purpose of this study was to evaluate the radiation doses during CT transmission scan by changing tube voltage and tube current, and to estimate the radiation dose during our clinical whole body $^{137}Cs$ transmission scan and high quality CT scan. Radiation doses were evaluated for Philips GEMINI 16 slices PET/CT system. Radiation dose was measured with standard CTDI head and body phantoms in a variety of CT tube voltage and tube current. A pencil ionization chamber with an active length of 100 mm and electrometer were used for radiation dose measurement. The measurement is carried out at the free-in-air, at the center, and at the periphery. The averaged absorbed dose was calculated by the weighted CTDI ($CTDI_w=1/3CTDI_{100,c}+2/3CTDI_{100,p}$) and then equivalent dose were calculated with $CTDI_w$. Specific organ dose was measured with our clinical whole body $^{137}Cs$ transmission scan and high quality CT scan using Alderson phantom and TLDs. The TLDs used for measurements were selected for an accuracy of ${\pm}5%$ and calibrated in 10 MeV X-ray radiation field. The organ or tissue was selected by the recommendations of ICRP 60. The radiation dose during CT scan is affected by the tube voltage and the tube current. The effective dose for $^{137}Cs$ transmission scan and high qualify CT scan are 0.14 mSv and 29.49 mSv, respectively. Radiation dose during transmission scan in the PET/CT system can measure using CTDI phantom with ionization chamber and anthropomorphic phantom with TLDs. further study need to be peformed to find optimal PET/CT acquisition protocols for reducing the patient exposure with same image qualify.

• Progress in Medical Physics
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• v.17 no.2
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• pp.105-113
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• 2006

This study peformed to confirm the corrected dose In different electron density materials using the superposition/FFT convolution method in radiotherapy Planning system. The experiments of the $K_2HPO_4$ diluted solution for bone substitute, Cork for lung and n-Glucose for soft tissue are very close to effective atomic number of tissue materials. The image data acquisited from the 110 KVp and 130 KVp CT scanner (Siemes, Singo emotions). The electron density was derived from the CT number (H) and adapted to planning system (Xio, CMS) for heterogeneity correction. The heterogeneity tissue phantom used for measurement dose comparison to that of delivered computer planning system. In the results, this investigations showed the CT number is highly affected in photoelectric effect in high Z materials. The electron density in a given energy spectrum showed the relation of first order as a function of H in soft tissue and bone materials, respectively. In our experiments, the ratio of electron density as a function of H was obtained the 0.001026H+1.00 in soft tissue and 0.000304H+1.07 for bone at 130 KVp spectrum and showed 0.000274H+1.10 for bone tissue in low 110 KVp. This experiments of electron density calibrations from CT number used to decide depth and length of photon transportation. The Computed superposition and FFT convolution dose showed very close to measurements within 1.0% discrepancy in homogeneous phantom for 6 and 15 MV X rays, but it showed -5.0% large discrepancy in FFT convolution for bone tissue correction of 6 MV X rays. In this experiments, the evaluated doses showed acceptable discrepancy within -1.2% of average for lung and -2.9% for bone equivalent materials with superposition method in 6 MV X rays. However the FFT convolution method showed more a large discrepancy than superposition in the low electron density medium in 6 and 15 MV X rays. As the CT number depends on energy spectrum of X rays, it should be confirm gradient of function of CT number-electron density regularly.

• Progress in Medical Physics
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• v.22 no.1
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• pp.35-41
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• 2011

For overall system test, hidden-target test have been used using film which leads to inherent analysis error. The purpose of our study is to quantify this error and to propose gel dosimeter based verification technique for 3-dimensional target point error. The phantom was made for simulation of human head and this has ability to equip 10 gel-dosimeter. $BANGkit^{TM}$ which we are able to manufacture whenever it is needed as well as to easily change the container with different shapes was used as a gel dosimeter. The 10 targets were divided into two groups based on shapes of areas with a planned 50% isodose line. All treatment and analysis was performed three times using Novalis and $BrainSCAN^{TM}$. The target point error is $0.77{\pm}0.15mm$ for 10 targets and directional target point error in each direction is $0.54{\pm}0.23mm$, $0.37{\pm}0.08mm$, $0.33{\pm}0.10mm$ in AP (anterior-posterior), LAT (lateral), and VERT (vertical) direction, respectively. The result of less than 1 mm shows that the treatment was performed through each precise step in treatment procedure. In conclusion, the 3-dimensional target point verification technique can be one of the techniques for overall system test.