• Journal of KIISE:Computer Systems and Theory
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• v.30 no.5_6
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• pp.324-329
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• 2003

The public-key cryptosystems such as Diffie-Hellman Key Distribution and Elliptical Curve Cryptosystems are built on the basis of the operations defined in GF(2$^{m}$ ):addition, subtraction, multiplication and multiplicative inversion. It is important that these operations should be computed at high speed in order to implement these cryptosystems efficiently. Among those operations, as being the most time-consuming, multiplicative inversion has become the object of lots of investigation Formant's theorem says $\beta$$^{-1}$ =$\beta$$^{2}$sup m/-2/, where $\beta$$^{-1}$ is the multiplicative inverse of $\beta$$\in$GF(2$^{m}$ ). Therefore, to compute the multiplicative inverse of arbitrary elements of GF(2$^{m}$ ), it is most important to reduce the number of times of multiplication by decomposing 2$^{m}$ -2 efficiently. Among many algorithms relevant to the subject, the algorithm proposed by Itoh and Tsujii[2] has reduced the required number of times of multiplication to O(log m) by using normal basis. Furthermore, a few papers have presented algorithms improving the Itoh and Tsujii's. However they have some demerits such as complicated decomposition processes[3,5]. In this paper, in the case of 2$^{m}$ -2, which is mainly used in practical applications, an efficient algorithm is proposed for computing the multiplicative inverse at high speed by using both the factorization formula x$^3$-y$^3$=(x-y)(x$^2$＋xy＋y$^2$) and normal basis. The number of times of multiplication of the algorithm is smaller than that of the algorithm proposed by Itoh and Tsujii. Also the algorithm decomposes 2$^{m}$ -2 more simply than other proposed algorithms.

• Cross-Cultural Studies
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• v.53
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• pp.163-192
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• 2018

The purpose of this paper was to examine universal dependency UD application cases of Korean and Japanese with similar morphological characteristics. In addition, UD application and improvement methods of Korean were examined through comparative analysis. Korean and Japanese are very well developed due to their agglutinative characteristics. Therefore, there are many difficulties to apply UD which is built around English refraction. We examined the application of UPOS and DEPREL as components of UD with discussions. In UPOS, we looked at category problem related to narrative such as AUX, ADJ, and VERB, We examined how to handle units. In relation to the DEPREL annotation system, we discussed how to reflect syntactic problem from the basic unit annotation of syntax tags. We investigated problems of case and aux arising from the problem of setting dominant position from Korean and Japanese as the dominant language. We also investigated problems of annotation of parallel structure and setting of annotation basic unit. Among various relation annotation tags, case and aux are discussed because they show the most noticeable difference in distribution when comparing annotation tag application patterns with Korean. The case is related to both Korean and Japanese surveys. Aux is a secondary verb in Korean and an auxiliary verb in Japanese. As a result of examining specific annotation patterns, it was found that Japanese aux not only assigned auxiliary clauses, but also auxiliary elements to add the grammatical meaning to the verb and form corresponding to the end of Korean. In UD annotation of Japanese, the basic unit of morphological analysis is defined as a unit of basic syntactic annotation in Japanese UD annotation. Thus, when using information, it is necessary to consider how to use morphological analysis unit as information of dependency annotation in Korean.

• Journal of Biomedical Engineering Research
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• v.24 no.5
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• pp.401-410
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• 2003

This study investigates the biomechanical efficacies of various cement augmentation techniques with or without pressurization for varying degrees of osteoporotic femur. For this study, a biomechanical analysis using a finite element method (FEM) was undertaken to evaluate surgical procedures, Simulated models include the non-cemented(i.e., hip screw only, Type I), the cement-augmented(Type II), and the cemented augmented with pressurization(Type III) models. To simulate the fracture plane and other interfacial regions, 3-D contact elements were used with appropriate friction coefficients. Material properties of the cancellous bone were varied to accommodate varying degrees of osteoporosis(Singh indices, II∼V). For each model. the following items were analyzed to investigate the effect surgical procedures in relation to osteoporosis of varying degrees : (a) von Mises stress distribution within the femoral head in terms of volumetric percentages. (b) Peak von Mises stress(PVMS) within the femoral head and the surgical constructs. (c) Maximum von Mises strain(MVMS) within the femoral head, (d) micromotions at the fracture plane and at the interfacial region between surgical construct and surrounding bone. Type III showed the lowest PVMS and MVMS at the cancellous bone near the bone-construct interface regardless of bone densities. an indication of its least likelihood of construct loosening due to failure of the host bone. Particularly, its efficacy was more prominent when the bone density level was low. Micromotions at the interfacial surgical construct was lowest in Type III. followed by Type I and Type II. They were about 15-20% of other types. which suggested that pressurization was most effective in limiting the interfacial motion. Our results demonstrated the cement augmentation with hip screw could be more effective when used with pressurization technique for the treatment of intertrochanteric fractures. For patients with low bone density. its effectiveness can be more pronounced in limiting construct loosening and promoting bone union.

• The Journal of Engineering Geology
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• v.26 no.2
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• pp.277-290
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• 2016

Deep geological cross-sectional data is generally not common nor easy to construct, because it is expensive and requires a great deal of time. As a result, geological interpretations at depth are limited. Many scientists attempt to construct geological cross-sections at depth using geological surface data and geophysical data. In this paper, we suggest a method for constructing cross-sections from limited geological surface data in a target area. The reason for this study is to construct and interpret geological cros-sections at depth to evaluate heat flow anomaly along the Yangsan fault. The Yangsan Fault passes through the south-eastern part of the Korean Peninsula. The cross-section is constructed from Sangbukmyeon to Unchonmyeon passing perpendicularly through the Yangsan Fault System trending NW-SE direction. The geological cross-section is constructed using the following data: (1) Lithologic distributions and main structural elements. (2) Extensity of sedimentary rock and igneous rock, from field mapping. (3) Fault dimension calculated based on geometry of exposed surface rupture, and (4) Seismic and core logging data. The Yangsan Fault System is composed of the Jain fault, Milyang fault, Moryang fault, Yangsan fault, Dongnae fault, and Ingwang fault which strike NNE-SSW. According to field observation, the western section of the Yangsan fault bounded by igneous rocks and in the eastern section sedimentary rocks are dominant. Using surface fault length we infer that the Yangsan Fault System has developed to a depth of kilometers beneath the surface. According to seismic data, sedimentary rocks that are adjacent to the Yangsan fault are thin and getting thicker towards the east of the section. In this study we also suggest a new method to recognize faults using core loggings. This analysis could be used to estimate fault locations at different scales.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.3
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• pp.197-204
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• 1989

To evaluate the effect of soil improvement on the chemical properties and corn silage yield, this experiment was carried out in the newly-reclaimed sloped land. Corn (Suwon 19) was cultivated under the six different treatments including integrated improvement plot at Songjeong loam, 20 percent slope, from 1985 to 1987 and various soil chemical properties and silage yield were investigated. pH of topsoil was above 5.0 except for control and phosphate plot, but lime and integrated improvement plots were above 5.0 in subsoil. The contents of organic matter of topsoil were above 2.0% except control and subsoiling plot. Except control, the range of cation exchange capacity was 7.4-7.8 me/100g in topsoil, 7.0-7.7 me/100g in subsoil. Soil bacteria density of root zone was the highest in integrated improvement than the other treatments, and it was higher at the harvesting stage than the heading stage. Mean density of microorganism was $61.3{\times}10^5$ in bacteria, $21.5{\times}10^4$ in fungi and actinomycetes was B/F ratio was 28.5 and B/A ratio was 2.9. Vertical root distribution of total and 10cm depth below was more in the integrated improvement and subsoi ling plot than the other plots. Total nitrogen (T-N) content was higher in integrated improvement plot, and phosphate content of leaves was higher in compost and integrated improvement plot, but stem and grain were not different. Potassium content of the plant was higher in integra ted improvement plot. Correlation between dry matter yield and T-N was more significant than the other elements. And the contents of phosphate, calcium and magnesium were significant at 5%, but potassium was not.

• Economic and Environmental Geology
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• v.40 no.5
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• pp.537-549
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• 2007

The characteristics of the mineralization and geology in the northern Mt. Taebaek mining district are found to be similar with those reported from Nevada district where the Carlin-type gold deposit occurs characteristically as repeated metallic ore deposits in space and time. Though two spots of hs and several spots of Sb anomalies were recognized in the Yeongweol area, they have no relationship with any metalliferous mineralization. On the other hand, two spots of As anomaly in the Jeongseon area have shown to be related with metalliferous ore deposits (mainly Ag-Au), and they are closely associated with Sb anomaly. Some elements of altered limestones in the study such as Au, Ag, As, Sb, Cu, Pb, Zn, and Mo area are closely associated together, and are more enriched in the Jeongseon area than in the Yeongweol area. In particular, Sb and As which may reflect the occurrence of the Carlin-type gold deposit are highly enriched. However, the base metals such af Zn and Pb are highly variable according to samples. The patterns of the enrichment factor for Sb and As, as well as those for Ag and Au, are very similar with those reported from the Carlin-type gold deposits in Nevada. These similarities in elemental distribution may imply that hydrothermal ore mineralization in the study areas was possibly originated from a fluid with the characteristics of the Carlin-type gold mineralization found in Nevada, China, and Indonesia. However, the pattern of base metals and Mo are different. This may result from different chemistry and/or mineralogy of host rock in the study areas.

• Management & Information Systems Review
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• v.39 no.2
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• pp.39-60
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• 2020

Block chain technology is one of the core elements for realizing the 4^th industrial revolution, and many efforts have been made by government and companies to provide services based on block chain technology. In this study we analyzed the benefits of block chain technology for EVMS and designed EVMS block chain platform with increased data security and work efficiency for project management data, which are important assets in monitoring progress, foreseeing future events, and managing post-completion. We did the case studies on the benefits of block chain technology and then conducted the survey study on security, reliability, and efficiency of block chain technology, targeting 18 block chain experts and project developers. And then, we interviewed EVMS system operator on the compatibility between block chain technology and EVM Systems. The result of the case studies showed that block chain technology can be applied to financial, logistic, medical, and public services to simplify the insurance claim process and to improve reliability by distributing transaction data storage and applying security·encryption features. Also, our research on the characteristics and necessity of block chain technology in EVMS revealed the improvability of security, reliability, and efficiency of management and distribution of EVMS data. Finally, we designed a network model, a block structure, and a consensus algorithm model and combined them to construct a conceptual block chain model for EVM system. This study has the following contribution. First, we reviewed that the block chain technology is suitable for application in the defense sector and proposed a conceptual model. Second, the effect that can be obtained by applying block chain technology to EVMS was derived, and the possibility of improving the existing business process was derived.

• Tunnel and Underground Space
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• v.13 no.1
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• pp.52-63
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• 2003

Discontinuities such as faults, fractures and joints in rock mass play the dominant role in the mechanical and hydraulic properties of the rock mass. The key factors that influence on the flow of groundwater are hydraulic and geometric characteristics of discontinuities and their connectivity. In this study, a program that analyzes groundwater flow in the 3D discontinuity network was developed on the assumption that the discontinuity characteristics such as density, trace length, orientation and aperture have particular distribution functions. This program generates discontinuities in a three-dimensional space and analyzes their connectivity and groundwater flow. Due to the limited computing capacity In this study, REV was not exactly determined, but it was inferred to be greater than 25$\times$25$\times$25 ㎥. By calculating the extent of aperture that influences on the groundwater flow, it was found that the discontinuities with the aperture smaller than 30% of the mean aperture had little influence on the groundwater flow. In addition, there was little difference in the equivalent hydraulic conductivity for the the two cases when considering and not considering the boundary effect. It was because the groundwater flow was mostly influenced by the discontinuities with large aperture. Among the parameters considered in this study, the length, aperture, and orientation of discontinuities had the greatest influence on the equivalent hydraulic conductivity of rock mass in their order. In case of existence of a fault in rock mass, elements of the equivalent hydraulic conductivity tensor parallel to the fault fairly increased in their magnitude but those perpendicular to the fault were increased in a very small amount at the first stage and then converged.

• Korean Journal of Agricultural and Forest Meteorology
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• v.5 no.3
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• pp.158-165
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• 2003

This study was conducted to reveal the role of meteorological elements on the habitat characteristics and vegetative structure for S. commixta natural populations at Ulleung Island. Potential Evapotranspiration(PET) by elevation of Ulleung Island was estimated using Thornthwaite's climatology estimating method. Also, Warm Index (WI), Coldness Index (CI) and vegetative composition by elevation were determined. The following results were obtained: The S. commixta trees wire mainly distributed from an elevation of 300 m to 900 m. The WI and CI were about 66.8∼95.0, -21.5∼-7.7, respectively. Water deficit by precipitation and Potential Evapotranspiration (PET) mainly occurred from March to October at all elevations. But wafer deficits diminished with increased elevation. The apparent species in S. commixta natural populations at Ulleung Island were: 10 tree layer species, 17 subtree layer species, and 25 species in the shrub layer. In the tree layer, S. commixta was dominant with the highest value of 46.85, then Fagus crenate 13.43, Acer mono and Tilia amurensis 12.41 and 12.03, respectively. In the subtree layer, A. mono was dominant with the highest value of 13.16, then F. crenata 12.68, Acer pseudo-sieboldianum and S. commixta 11.37 and 10.76, respectively. Dominant species and IV values in the shrub layer were Sasa borealis (22.09) and Rhododendron brachycarpum (10.51). The S. commixta natural forests were in a relatively stable rendition because of the even distribution of its various indexes: the species diversity index of Shannon, the evenness index and dominance were 0.6199∼1.1390, 0.6199∼0.8825 and 0.1852∼0.3801, respectively.

• Korean Journal of Environmental Agriculture
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• v.13 no.2
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• pp.160-167
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• 1994

Meteorological elements such as air temperature, relative humidity, rainfall, sunshine duration, and so on observed by Korea Meteorological Administration, were analyzed to estimate the climatic change and to establish countermeasures in agriculture. Climatic differences were compared between two periods, early($1931{\sim}1960$) and late($1961{\sim}1990$), by calculating climatic resource indices, coldness index and warmth index of the two periods. Annual mean air temperatures of Seoul, Taegu, and Pusan in 1910's were 10.7, 12.3, and $13.4^{\circ}C$, respectively, having increased by $1.3^{\circ}C$ in Seoul and Taegu and by $0.9^{\circ}C$ in Pusan in 1990's. Mean air temperature in the spring($March{\sim}May$) increased by $0.69^{\circ}C$, which is a higher increasing rate than in the other seasons ($0.26{\sim}0.33^{\circ}C$). Regional differences exist in annual mean air temperature between the early and late part of the 20th century with little increase in this experiment did not germinate at pH 1.0. At pH 2.0, the flowering cabbage and geranium in the middle northern area, while in the southern part about $1^{\circ}C$increase was recorded during the last period. In the late period the annual rainfall increased by 100mm, except for the western coast area and the middle northern area. The P/E ratio showed a trend of an annual increase in the late period, being higher in the summer and lower in the winter. Relative humidity showed slight differences in seasons and regions but annual values did not. Duration of sunshine decreased by about an hour in the spring. Coldness index and warmth index of the late period were higher by 3.7 and 1.0 than those of the early period, respectively.