• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.4
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• pp.293-301
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• 2006

This paper proposes a control algorithm for STATic synchronous COMpensator(STATCOM), based on Space Vector Modulation(SVM) and Hysteresis Current Controller(HCC) techniques. STATCOM is used to reactive power compensation on a distribution network. The proposed algorithm utilizes the advantages of the fast dynamic response of the hysteresis current control and the reduced switching number of the SVM scheme. The controller determines a set of space vectors from a region detector and applies a space vector. A set of space vectors including the zero vector, to reduce the number of switching, is determined from output signals of two hysteresis comparators. The presented control system was tested with digital simulation in the Borland C++ program and demonstrate the advantage of the proposed hysteresis current controller.

• Journal of Digital Contents Society
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• v.13 no.2
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• pp.225-233
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• 2012

The 3D stereoscopic image contents have been emerging as the blue chip of the contents market of the next generation since the . However, all the 3D contents created commercially in the country have failed to enter box office. It is because the quality of Korean 3D contents is much lower than that of overseas contents and also current 3D post production process is based on 2D. Considering all these facts, the 3D editing process has connection with the quality of contents. The current 3D editing processes of the production case of are using the way that edits with the system on basis of 2D, followed by checking with 3D display system and modifying, if there are any problems. In order to improve those conditions, I suggest that the 3D editing process contain more objectivity by visualizing the depth data applied in some composition work such as Disparity map, Depth map, and the current 3D editing process. The proposed process has been used in the music drama , comparing with those of the film . The 3D values could be checked among cuts which have been changed a lot since those of , while the 3D value of drew an equal result in general. Since the current process is based on an artist's subjective sense of 3D, it could be changed according to the condition and state of the artist. Furthermore, it is impossible for us to predict the positive range, so it is apprehended that the cubic effect of space might be perverted by showing each different 3D value according to cuts in the same space or a limited space. On the other hand, the objective 3D editing by applying the visualization of depth data can adjust itself to the cubic effect of the same space and the whole content equally, which will enrich the 3D contents. It will even be able to solve some problems such as distortion of cubic effect and visual fatigue, etc.

• The Journal of Korean Medicine
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• v.31 no.5
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• pp.82-89
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• 2010

Objectives: The aim of this study was to determine distribution patterns of TOAST subtypes of ischemic stroke patients admitted to oriental hospitals and to get a better understanding of present conditions in oriental medicine by comparing with the Korea stroke registry (KSR), the largest and representative data. Methods: Clinical data were collected from acute ischemic stoke patients. MRI studies including vascular images were performed in all cases. TOAST criteria were used to determine subtypes of ischemic stroke patients. According to the duration from disease onset to hospital admission time, patients were assigned to 3 groups (Group I0 to 3 d, Group II4 to 7 d, Group III8 to 28 d) and the distribution of TOAST subtypes were compared among these three groups. Results: We collected 514 sets of clinical data from 10 oriental hospitals between May 2007 and September 2009. Small vessel occlusion (SVO) subtype was the most common (57.62%), followed by large artery atherosclerosis (LAA, 29.98%). Compared with TOAST distribution of KSR, the proportion of ischemic stroke patients with SVO subtype was higher than that of KSR. On the other hand the proportion of patients with stroke of undetermined etiology (SUE) was lower. Distributions of SVO, LAA and cardioembolism (CE) in group were I 66.4%, 23.8% and 8.9%, respectively; those in group IIIwere 51.03%, 34.71% and 11.57%, respectively. Conclusions: In oriental hospitals, the proportion of ischemic stroke patients diagnosed as SVO type was higher than that of KSR. At early stage (from onset to 2 d) proportion of SVO was very high, however after 7 days from onset it decreased with concomitant increases in proportions of LAA and CE. These phenomena may be due to the facts that 1) at early stage emergency treatments are limited in oriental hospitals, 2) after early stage many patients prefer oriental treatments, including rehabilitation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.8
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• pp.1604-1610
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• 2017

Using analytical solution of $B({\xi})$, I could find out the characteristics of Submarine's turbulent wake for the given various ${\lambda}$, which were unknown facts before. As the results, $B({\xi}){\approx}{\frac{B({\xi})_{max}}{2}}$ and ${{\int}_{0}^{{\approx}0.6}}B({\xi})d{\xi}{\approx}0.85{{\int}_{0}^{1}}B({\xi})d{\xi}$ in the vicinity ${\xi}{\approx}0.6$, there was some dependencies on the given ${\lambda}$ though. The values of ${\lambda}$, in the range of $4{\leq}{\lambda}{\leq}8$, are more suitable to describe submarine's turbulent wake realistically, due to the bases on the quasi equilibrium state of turbulent wake. ${\lambda}$ mainly affects on the radius and detection range of the submarine's turbulent wake on the surface, however, the speed of submarine mainly affect on the duration of the wake rather than shape. If $7{\leq}{\lambda}{\leq}8$, it can be expected that the turbulent wake can be seen on the surface in the West sea, however, snorkeling(or snorkeled) submarine's wake can be found easily in the East sea.

• Journal of the Korean earth science society
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• v.38 no.7
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• pp.511-521
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• 2017

This study analyzes Two-dimensional video disdrometer (2DVD) data while summer 2011-2012 in Daegu region and compares with Marshall and Palmer (MP) distribution to find out statistical characteristics and characteristics variability about drop size distribution (DSD) of Daegu region. As the characterize DSD of Daegu region, this study uses single moment parameters such as rainfall intensity (R), reflectivity factor (Z) and double moment parameters such as generalized characteristics number concentration ($N{_0}^{\prime}$) and generalized characteristics diameter ($D{_m}^{\prime}$). Also, this study makes an assumption that DSD function can be expressed as general gamma distribution. The results of analysis show that DSD of Daegu region has ${\log}_{10}N{_0}^{\prime}=2.37$, $D{_m}^{\prime}=1.04mm$, and c =2.37, ${\mu}=0.39$ on average. When the assumption of MP distribution is used, these figures then end up with the different characteristics; ${\log}_{10}N{_0}^{\prime}=2.27$, $D{_m}^{\prime}=0.9mm$, c =1, ${\mu}=1$ on average. The differences indicate liquid water content (LWC) of Daegu distribution is generally larger than MP distribution at equal Z. Second, DSD shape of Daegu distribution is concave upward. Other important facts are the characteristics of Daegu distribution change when Z changes. DSD shape of Daegu region changes concave downward (c =2.05~2.55, ${\mu}=0.33{\sim}0.77$) to cubic function-like shape (c =3.0, ${\mu}=-0.13{\sim}-0.33$) at Z > 45 dBZ. 35 dBZ ${\leq}$ Z > 45 dBZ group of Daegu distribution has characteristics similar to maritime cluster of diverse climate DSD study. However, Z > 45 dBZ group of Daegu distribution has a difference from the cluster.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.6
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• pp.1571-1582
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• 2015

This paper suggests a methodology for linking technology classification of nongovernmental information security field and technology classification of cyber-warfare in national defense field. Based on this methodology, Multi-Attribute Utility Theory(MAUT) is applied for the purpose of selecting promising nongovernmental technology that is worthy of later introduction or development. After studying the result of the survey regarding the research progression plan of the selected promising technology, the following three facts are discovered: Firstly, the greater the social spillover effect, the greater the need for the government lead R&D. Secondly, among the spillover effects, the social aspect has the highest correlation with respect to the need for the government lead R&D, while the economical aspect and the technological aspect come in the second and the third place, respectively. Finally, according to the correlation analysis, the defense application and the technological importance do not affect the subject of investment or the subject of development. This indicates that even though the R&D for technology with high social spillover effect should be lead by the government, the subject of the investment or the development cannot be determined solely by factors such as military application and technological importance.

• School Mathematics
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• v.19 no.2
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• pp.289-317
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• 2017

This study aims to explore how Korean middle-school mathematics textbooks on functions provide students an opportunity-to-learn [OTL]. For this purpose, we investigate 3 textbooks in terms of mathematics content and practice, the level of cognitive demands of mathematical tasks, types of student responses, types of context-based tasks, and connections among the tasks. The findings from the data analysis suggest as follows: a) an opportunity-to-learn to connect procedures to functional concepts and new ideas of functions to the existing one is very limited; b) the textbooks seem to provide students an OTL to understand functions as definitions, rules and conventions and to experience repeatedly procedural executions through worked examples and mathematics tasks; c) students may not experience to explain their own ideas/thinking by using mathematical sentence or justify their own cognitive processes; and d) students can be exposed to get a sense of mathematics as a set of fragmented and isolated facts or procedures, rather than to encourage to expand and deepen their understanding of functions.

• The Korean Journal of Ecology
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• v.19 no.5
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• pp.417-430
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• 1996

This study was conducted to investigate the developmental process of plant community during the secondary succession and the dynamics of soil properties in the burned and unburned areas of Mt. Ch’oly-san. Owing to the forest fire occurred on April, 1989, the red pine(Pinus densiflora) forest and its floor vegetation were burned down. The floristic composition of burned and unburned areas were composed of 53 and 49 species of vascular plants, respectively. The dominant species based on SDR4 of the burned sites were lespedeza cyrtobotrya (89.62), Miscanthus sinensis var. purpurascens (62.50), and Carex humilis (58.73), Quercus serrata (43.33). In contrast, Pinus densiflora (83.56), Lespedeza cyrtobotrya (55.57), Miscanthus sinensis var. purpurascens (51.88) and Carex humilis (50.41) were dominant in the unburned area. The biological spectra showed the $H-D_1-R_5-e$ type in both the burned and unburned areas. The indices of similarity ($CC_S$) between the two areas were 0.74. Degree of succession (DS) was 604 in the burned area and 802 in the unburned area. From these facts, it is assumed that the succession is rapidly progressing because of the recovery of vegetation. The species diversity ($\={H}$) and evenness index(C) in the burned and unburned areas were 0.15 and 0.18, respectively. Red pine tree did not resprout after scorch by the forest fire, but Lespedeza, Quercus, Rhododendron, Albizzia, and Zanthoxylum resprouted from the roots and trunks after the forest fire. It seems that these species are the fire-resistant species. Soil properties such as soil pH, content of organic matter, available phosphous, total nitrogen, tatal carbon, exchangeable potssium, sodium, calcium, and magnesium increased due to forest fire. These results suggest the intensity of forest fire in the study area was relatively weak. Monthly changes of soil properties were of little significance except for some cases.

• Journal of the Korean Home Economics Association
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• v.33 no.5
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• pp.211-219
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• 1995

In this study of the Buddhist Stone Statues in Namsan in Kyungju. We have found out interesting facts as follow. This study is focused on the way the Buddhist Statues wear the robes. There are two basical types of wearing ; Tongkyun and Pyundanwookyun. In Silla, these types of wearing has been developed into its unique types based on the traditional culture. The stone Buddhist images show seven types of wearing based on the standard ones of Tongkyun and Pyundanwookyun. This variety in wearing rests on the various of Sungkari(Samghathi) and Bokgyenui(Samkaksika) and a chest sash which fixes Niwonsung(Nivasana). There are three cases inferred from the seven types of wearing the Buddha's robes : (1)Tonkyun type A: The only outer wear Sungkari(Samghathi) was put on as Tongkyun type. We can't find out any Bokgyenui(Samkaksika) or the chest sash of Niwonsung(Nivasana). (2)Tongkyun type B: Bokgyenui(Samkaksika) is put on the chest of Statue in Sungkari(Samghathi). (3)Tongkyun type C: This type is similar to Tonkyun type A, except that the end of the robe dangled down straight to the right side. (4)Tongkyun type D: Bokgyenui(Samkaksika) is bound with a chest sash. (5)Tongkyun type C: The robe is tied on the left shoulder as a cord and Bokgyenui(Samkaksika) is bound with a chest sash. (6)Pyundanwookyun type A: The robe dangled down from the left shoulder to the right armpit diagonally, so left shoulder is naked. (7)Pyundanwookyun type B: This type is similiar to Pyundanwookyun type A, but the end of Sungkari(Samghathi) is bound up to the left shoulder again. Considering above, the robe types of Buddha seem to have something to do with those of the Silla people: The chest sash is similar to the adjustment of Jeogori(the traditional jacket) of the Silla, and the typing cord in Buddha's robe corresponds to that of the traditional types.

• Journal of the Korean Magnetic Resonance Society
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• v.3 no.2
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• pp.100-108
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• 1999

Cop protein is the transcription repressor protein in rolling circle replication plasmid. With antisense RNA, Cop protein controls the copy number of plasmid. Cop family proteins have been found in various plasmids. Among Cop family proteins, Cop studied in this paper consists of 55 amino acids (Mw. 6,400), and was known to have trimer structure. Since no structural facts are elucidated, we have carried out preliminary experiments aimed at the elucidation of its three dimensional structure. The secondary structure of Cop is studied by CD and NMR. To solve the aggregation of Cop at high concentration, we tested various detergents and salts. The addition of detergents and salts could not solve the aggregation problem. However, we found that concentration is important in solving the aggregation problem. We knew that 0.18mM in 50mM potassium phosphate without any other ingredients is maximum concentration not to aggregate. Wa also investigated the pH dependence of Cop protein, and knew that Cop protein is more stable in acid state. At various temperatures, 15N-1H HSQC spectra were measured in order to find the optimal experimental condition. To enhance the peak resolution, 3D NOESY-HSQC spectrum is acquired. Since there are NOE peaks in the NH-NH region, we knew that Cop protein has $\alpha$-helical content, which was also confirmed by CD.