• Progress in Medical Physics
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• v.26 no.1
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• pp.18-27
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• 2015

Since a Compton camera has high detection sensitivity due to electronic collimation and a good energy resolution, it is a potential imaging system for nuclear medicine. In this study, we investigated the feasibility of a Compton camera for multi-tracer imaging and proposed a rotating Compton camera to satisfy Orlov's condition for 3D imaging. Two software phantoms of 140 and 511 keV radiation sources were used for Monte-Carlo simulation and then the simulation data were reconstructed by listmode ordered subset expectation maximization to evaluate the capability of multi-tracer imaging in a Compton camera. And the Compton camera rotating around the object was proposed and tested with different rotation angle steps for improving the limited coverage of the fixed conventional Compton camera over the field-of-view in terms of histogram of angles in spherical coordinates. The simulation data showed the separate 140 and 511 keV images from simultaneous multi-tracer detection in both 2D and 3D imaging and the number of valid projection lines on the conical surfaces was inversely proportional to the decrease of rotation angle. Considering computation load and proper number of projection lines on the conical surface, the rotation angle of 30 degree was sufficient for 3D imaging of the Compton camera in terms of 26 min of computation time and 5 million of detected event number and the increased detection time can be solved with multiple Compton camera system. The Compton camera proposed in this study can be effective system for multi-tracer imaging and is a potential system for development of various disease diagnosis and therapy approaches.

• Informatization Policy
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• v.23 no.3
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• pp.26-42
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• 2016

Recently, with the rapid growth of the O2O market, Fintech combining the finance and ICT technology is drawing attention as innovation to lead "O2O of finance", along with Fintech-based payment, authentication, security technology and related services. For new technology industries such as Fintech, technical sources, related systems and regulations are important but previous studies on Fintech lack in-depth research about systems and technological trends of the domestic Fintech industry. Therefore, this study aims to analyze domestic Fintech trends and find the insights for the direction of technology and systems of the future domestic Fintech industry by comparing Kakao Pay and Samsung Pay, the two domestic representative mobile payment services. By conducting a complete enumeration survey about the tweets mentioning Fintech until June 2016, this study visualized topics extraction, sensitivity analysis and keyword analyses. According to the analysis results, it was found that various topics have been created in the technologies and systems between 2014 and 2016 and different keywords and reactions were extracted between topics of Samsung Pay based on "devices" such as Galaxy and Kakao Pay based on "service" such as KakaoTalk. This study contributes to analyzing the unstructured data of social media by period by using social media mining and quantifying the expectations and reactions of consumers to services through the sentiment analysis. It is expected to be the foundation of Fintech industry development by presenting a strategic direction to Fintech related practitioners.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.585-593
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• 2020

Until now, 29 fire accidents have occurred; 22 of them were caused by the interconnection of renewable energy sources that occurred during the rest period after the lithium-ion battery had been fully charged regardless of the seasons. The fire accidents of ESS were attributed to thermal runaway due to the overcharging of a few cells with the phenomenon of self-energy balancing, which is unintentional current flow from cells with a high SOC to the low cells if the SOC condition of each cell connected in parallel is different. Therefore, this paper proposes a novel configuration and operation algorithm of the BMS to prevent the self-energy balancing of ESS and presents a hybrid SOC estimation algorithm. From the test results of the self-energy balancing phenomenon between aging and normal cells based on the proposed algorithm and BMS, it was confirmed the possibility of self-energy balancing, which is unintentional current flow from cells with a high SOC to cells with a low SOC. In addition, the proposed configuration of the BMS is useful and practical to improve the safety of lithium-ion batteries because the BMS can reliably disconnect a parallel connection of the cells if the self-energy balancing current becomes excessively high.

• KIPS Transactions on Software and Data Engineering
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• v.9 no.4
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• pp.129-136
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• 2020

PM2.5 which is a very tiny air particulate matter even smaller than PM10 has been issued in the environmental problem. Since PM2.5 can cause eye diseases or respiratory problems and infiltrate even deep blood vessels in the brain, it is important to predict PM2.5. However, it is difficult to predict PM2.5 because there is no clear explanation yet regarding the creation and the movement of PM2.5. Thus, prediction methods which not only predict PM2.5 accurately but also have the interpretability of the result are needed. To predict hourly PM2.5 of Seoul city, we propose a method using random forest with the adjusted bootstrap number from the time series ground data preprocessed on different sources. With this method, the prediction model can be trained uniformly on hourly information and the result has the interpretability. To evaluate the prediction performance, we conducted comparative experiments. As a result, the performance of the proposed method was superior against other models in all labels. Also, the proposed method showed the importance of the variables regarding the creation of PM2.5 and the effect of China.

• The Journal of Korean Medicine
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• v.32 no.2
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• pp.14-22
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• 2011

Objective: Nowadays the combined use of herbal extracts and western medicines has been prevalent, but concern about its risk is also increasing. Even though the importance of clinical trials is well recognized, there have been only a few studies on the combined use of herbal extracts and western medicines. This study was aimed to examine which herbal extracts and antiplatelets or anticoagulants are most commonly prescribed together to inpatient ischemicstroke patients and investigate the combined prescription rate. Methods: We investigated the most frequently prescribed herbal extracts from two different sources. First, we chose herbal medicine extracts from 2008 Traditional Korean Medicine Utilization Status. Then, among patients who were admitted to Kyung-Hee Oriental Medical Center diagnosed with ischemic stroke, we found patients who were administered with these herbal medicine extracts and among these patients, we investigated how many were concomitantly administered with antiplatelets or anticoagulants. Second, we chose other herbal medicine extracts that were most often prescribed within Kyung-Hee Oriental Medical Center and found patients who were administered with these herbal medicine extracts, then investigated how many of them were concomitantly administered with specific antiplatelets or anticoagulants. Results: The most commonly prescribed herbal medicine extracts among ischemic stroke patients were Ojeok-san, Bojungikgi-tang, Sochungryong-tang and Samsoeum. About 46 to 69 percent were concomitantly administered with either specific antiplatelets or anticoagulants. Conclusions: The most often prescribed herbal medicine extracts in inpatient ischemic stroke patients are Ojeok-san, Bojungikgi-tang, Sochungryong-tang, and Samsoeum. Among patients who were prescribed with Ojeok-san, Bojungikgi-tang, Sochungryong-tang, Samsoeum, patients who were concomitantly administered with either antiplatelets or anticoagulants were about 46% to 69%.

• Journal of Korean Society of Forest Science
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• v.65 no.1
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• pp.43-47
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• 1984

Pinus rigida ${\times}$ P. taeda seedlings in a nursery was inoculated with basidiospores of Pisolithus tinctorius (Pt) either collected from Suweon, Korea or introduced from U.S.A. to compare the effectiveness of the spores from two different origins as mycorrhizal inocula. Nursery beds were fumigated with methyl bromide and 1g of spores was used to inoculate $1m^2$ of soil surface just before seed sowing. Seedlings inoculated with American Pt (#250 strain from Georgia, U.S.A.) were 15% taller than Korean Pt at the end of the first growing season. The seedlings from fumigation treatment only (no inoculation involved) was slightly taller (statistically unsignificant) than those with Korean Pt, but slightly smaller than those with American Pt. In a subsequent year experiment, the seedlings inoculated with American and Korean Pt after soil fumigation were 66% and 60% taller, respectively, than seedlings infected by natural fungi without soil fumigation, suggesting the dual effects of Pt and fumigation on the seedling growth. Therefore potential of Pt spores for an effective inoculum exists and selection of Pt strains which have adapted to specific local environments is needed to develop better sources of mycorrhizal inocula.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2002.07a
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• pp.25-37
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• 2002

The most important industrial application of gamma radiation in characterizing green compacts is the determination of the density. Examples are given where this method is applied in manufacturing technical components in powder metallurgy. The requirements imposed by modern quality management systems and operation by the workforce in industrial production are described. The accuracy of measurement achieved with this method is demonstrated and a comparison is given with other test methods to measure the density. The advantages and limitations of gamma ray densitometry are outlined. The gamma ray densitometer measures the attenuation of gamma radiation penetrating the test parts (Fig. 1). As the capability of compacts to absorb this type of radiation depends on their density, the attenuation of gamma radiation can serve as a measure of the density. The volume of the part being tested is defined by the size of the aperture screeniing out the radiation. It is a channel with the cross section of the aperture whose length is the height of the test part. The intensity of the radiation identified by the detector is the quantity used to determine the material density. Gamma ray densitometry can equally be performed on green compacts as well as on sintered components. Neither special preparation of test parts nor skilled personnel is required to perform the measurement; neither liquids nor other harmful substances are involved. When parts are exhibiting local density variations, which is normally the case in powder compaction, sectional densities can be determined in different parts of the sample without cutting it into pieces. The test is non-destructive, i.e. the parts can still be used after the measurement and do not have to be scrapped. The measurement is controlled by a special PC based software. All results are available for further processing by in-house quality documentation and supervision of measurements. Tool setting for multi-level components can be much improved by using this test method. When a densitometer is installed on the press shop floor, it can be operated by the tool setter himself. Then he can return to the press and immediately implement the corrections. Transfer of sample parts to the lab for density testing can be eliminated and results for the correction of tool settings are more readily available. This helps to reduce the time required for tool setting and clearly improves the productivity of powder presses. The range of materials where this method can be successfully applied covers almost the entire periodic system of the elements. It reaches from the light elements such as graphite via light metals (AI, Mg, Li, Ti) and their alloys, ceramics ($AI_20_3$, SiC, Si_3N_4, $Zr0_2$, ...), magnetic materials (hard and soft ferrites, AlNiCo, Nd-Fe-B, ...), metals including iron and alloy steels, Cu, Ni and Co based alloys to refractory and heavy metals (W, Mo, ...) as well as hardmetals. The gamma radiation required for the measurement is generated by radioactive sources which are produced by nuclear technology. These nuclear materials are safely encapsulated in stainless steel capsules so that no radioactive material can escape from the protective shielding container. The gamma ray densitometer is subject to the strict regulations for the use of radioactive materials. The radiation shield is so effective that there is no elevation of the natural radiation level outside the instrument. Personal dosimetry by the operating personnel is not required. Even in case of malfunction, loss of power and incorrect operation, the escape of gamma radiation from the instrument is positively prevented.

• The Korean Journal of Quaternary Research
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• v.7 no.1
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• pp.69-91
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• 1993

A total of 76 surface sediment samples, collected from the Korean west coast and the eastern Yellow Sea areas, were analyzed for their elemental composition in order to understand the geochemical characteristics of these deposits. The analyzed elements included 9 major elements (Al, Fe, Na, K, Mg, Ca, Ti, P, Mn), 8 minor elements (Sr, Ba, V, Cr, Co, Ni, Cu, Zn), organic carbon and calcium carbonate. Contents of most analyzed elements, excluding K and Ba, were generally low compared to those of average crust. Contents of most elements, except K and Ca, also correlated with sediment grain size, though the degree of relationship varied widely from one element to another. For fine-grained sediments, a distinction could be made between those in the central Yellow Sea and those in the Keum Estuary based on their characteristic elemental composition: the former were rich in Fe, Na, K, Mg, Ca and V, and the latter in Mn, Co and Ni. The element/aluminium ratios, on the other hand, showed that the central Yellow Sea muds were enriched in Fe, Mg, V, Ni, Cu and Zn and depleted in K, Mn, Ba and Sr relative to the mud located near the Korean Peninsula. Based on the analysis of these results, as well as of the influences of particular mineral phases or pollution effects, we could suggest geochemical criteria which can be used in distinguishing muds from the two different sources, the Keum River and the Yellow River: the former by the higher Mn content and the latter by the higher Mg and V contents, relative to each other.

• Korean Journal of Community Nutrition
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• v.21 no.3
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• pp.284-292
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• 2016

Objectives: This study compared the differences of postmenopausal women's bone mineral density in relation to the degree of obesity, metabolism index and dietary factors that affect bone mineral density. Methods: The subjects included in the study are 39 postmenopausal women of normal weight with body mass index less than $25kg/m^2$ and 32 postmenopausal who are obese. Anthropometry and biochemical analysis were performed and nutrient intakes and DQI-I were assessed. Results: Normal weight women were $56.03{\pm}3.76years$ old and obese women were $58.09{\pm}5.13years$ old and there was no significant difference in age between the two groups. The T-score of bone mineral density was $0.03{\pm}1.06$ in normal weight women and $-0.60{\pm}1.47$ in obese women and this was significantly different between the two groups (p<0.05). Blood Leptin concentration was significantly lower in normal weight women ($6.09{\pm}3.37ng/mL$) compared to obese women in ($9.01{\pm}4.99ng/mL$) (p<0.05). The total score of diet quality index-international was $70.41{\pm}9.34$ in normal weight women and $64.93{\pm}7.82$ in obese women (p<0.05). T-score of bone mineral density showed negative correlations with percentage of body fat (r = -0.233, p=0.05), BMI (r = -0.197, p=0.017), triglyceride (r = -0.281, p=0.020) and leptin (r = -0.308, p=0.011). The results of multiple regression analysis performed as the method of entry showed that with 22.0% of explanation power, percentage of body fat (${\beta}=-0.048$, p<0.05), triglyceride (${\beta}=-0.005$, p<0.05) and HDL-cholesterol (${\beta}=0.034$, p<0.01), moderation of DQI-I (${\beta}=-0.231$, p<0.05) affected T-score significantly. Conclusions: The results of the study showed that obese women have less bone density than those with normal weight women. In addition, the factor analysis result that affect bone mineral density showed that intake of fat is a very important factor. Therefore, postmenopausal women need to maintain normal weight and manage blood lipid levels within normal range. They also need to take various sources of protein and reduce consumption of empty calorie foods that have high calories, fat, cholesterol and sodium.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.3
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• pp.252-262
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• 2014

Sorghum seed is traditionally used as secondary food sources in addition to rice in Korea. While the hypoglycemia regulating phytochemicals have been found in sorghum seed, peptides related with hypoglycemia never been studied before. To obtain the peptide characteristics and the specifically high-expressed peptides in hypoglycemic sorghum seed, peptide profiles of seven hypoglycemic and five non-hypoglycemic sorghum lines bred in RDA were determined using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS). The twelve sorghum lines exhibited 104 peptides on CM10 protein chip array (weak cation exchange) and 95 peptides on Q10 (weak cation exchange) in the molecular mass range from 2,000 to 20,000 Da. Heat map via supervised hierarchical clustering of the significantly different peptides (p < 0.01) in peak intensity among the 12 lines effectively revealed the specifically upregulated peptides in each line and distinguished between 7 hypoglycemic and 5 non-hypoglycemic lines. Through the comparison with hypoglycemic and non-hypoglycemic lines, 10 peptides including 2231.6, 2845.4, 2907.9, 3063.5, 3132.6, 3520.8, 4078.8, 5066.2, 5296.5, 5375.5 Da were specifically high-expressed in hypoglycemic lines at p < 0.00001. This study characterized seed peptides of 12 sorghums and found ten peptides highly expressed for hypoglycemic sorghum lines, which could be used as peptide biomarkers for identification of hypoglycemic sorghum.