• Journal of Korea Society of Industrial Information Systems
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• v.18 no.6
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• pp.95-101
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• 2013

Social media has many advantages. It can gain latest information with real time, be spread rapidly, easily be reproduced and distributed regardless of its form. These advantages can result in real time predictions using the latest information, which is possible due to the increase in social demand for more quick and accurate economic variable predictions. In this paper we adopted ARIMAX and ECM model to predict the unemployment rate and as a social information we used the Google Index provided by Google Trend. Also we used News Index as a domestic social information. The process of fitting statistical model considered in this paper can be adopted to predict various socio/economic indices as well as unemployment rate.

• Macromolecular Research
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• v.11 no.4
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• pp.236-240
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• 2003

Fabrication of a graded index profile was possible via photochemical reaction of cinnamoyl groups with 350 nm wavelength UV light to form crosslinked structures. Such structural change may induce the change in the refractive index. In order to generate graded index profile in the PMMA polymer optical fiber (POF) with cinnamoyl groups by photochemistry, a methyl methacrylate monomer containing a cinnamoyl functional group in the side chain were prepared. This monomer was then copolymerized with methyl methacrylate with various compositions not only to utilize advantages of poly(methyl methacrylate) but also to overcome the drawbacks of the cinnamate homopolymer. Changes of refractive indices were investigated with various contents of cinnamoyl group and varying irradiation time. Large change in the refractive index (${\Delta}{\approx}0.01$) and its proper profile shape ($g{\approx}2.2$) can be obtained by changing irradiation time.

• Geomechanics and Engineering
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• v.21 no.4
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• pp.391-399
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• 2020

Brittleness is one of the most important properties of rock which has a major impact not only on the failure process of intact rock but also on the response of rock mass to tunneling and mining projects. Due to the lack of a universally accepted definition of rock brittleness, a wide range of methods, including direct and indirect methods, have been developed for its measurement. Measuring rock brittleness by direct methods requires special equipment which may lead to financial inconveniences and is usually unavailable in most of rock mechanic laboratories. Accordingly, this study aimed to develop a new strength-based index for predicting rock brittleness based on the obtained base form. To this end, an innovative algorithm was developed in Matlab environment. The utilized algorithm finds the optimal index based on the open access dataset including the results of punch penetration test (PPT), uniaxial compressive and Brazilian tensile strength. Validation of proposed index was checked by the coefficient of determination (R²), the root mean square error (RMSE), and also the variance for account (VAF). The results indicated that among the different brittleness indices, the suggested equation is the most accurate one, since it has the optimal R², RMSE and VAF as 0.912, 3.47 and 89.8%, respectively. It could finally be concluded that, using the proposed brittleness index, rock brittleness can be reliably predicted with a high level of accuracy.

• Journal of Arbitration Studies
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• v.32 no.1
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• pp.93-110
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• 2022

Korea, a resource-scarce country, has been undergoing export-led economic growth in the form of processing and intermediary trade for the past several decades. In Korea, which has an export-led economic structure centered on processing trade, the export economy precedes the domestic economy, so Korea's monthly export performance has been used as an important indicator of economic indicators in itself. In recent decades, small and medium-sized enterprises (SMEs), which account for 99% of the total number of domestic enterprises, account for about 35% of exports as of 2021. In this study, from the viewpoint of emphasizing the export contribution of SMEs, the Small and Medium-sized Enterprise Export Business Index is developed based on the actual export performance of SMEs, through which this paper could present alternative index differentiated from the existing Business Survey Indexes.

• Journal of the Korean Society of Industry Convergence
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• v.6 no.4
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• pp.315-324
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• 2003

The purpose of this is to evaluate Hakui Stream Naturalness Index(S.N.I). and to find out stats, problems and opportunities of the Hakui stream by assessment standard. Assessment standard is mainly based on physical structure of stream environment. The purpose evaluating sectors and elements are physical form and structure restoration of stream. To find out assessment standard of stream naturalness index, conceptual frame of assessment standard has been established, for which four sections, for example, longitudinal section, lateral section, stream bottom structure and water environment, have been selected. Overall stream naturalness index of the Hakui stream has been distributed at 3rd to 4th grade, and its assessment index accounted for 3.2 to be 3rd grade, and its mode also did 3rd grade. Stream naturalness index of each section was as follows: Longitudinal section index accounted for 3.6 in average to be 4th grade, and later section index did 3.0 to be 3rd grade, and stream bottom structure index did 3.0 to be 3rd grade, and water environment index did 2.7 to be 3rd grade. Analysis of assessment outcome of stream naturalness index has checked status, Problems and opportunities of corresponding stream. Assessment of stream naturalness index of the study provides useful information for restoration of close-to-nature stream, and furthermore has its meaning in checking problems and opportunities of Hakui stream.

• The Korean Journal of Ecology
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• v.6 no.3
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• pp.187-197
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• 1983

This report is a series of the investigation of the secondary vegetation and succession at the forest fire area in Dangji-Dong of Kyungsang-pookdo province. The forest fires occurred on April 8, 1982. This investigation was carried out from June 18, 1982 to May 29, 1983 once in each season. Before to fires, the Pinus densiflora was dominant and the woody plants of understory were mainly composed of the Quercus serrata, Q. dentata, Lespedeza maritima and L. macimowiczii. Compared with the florstic composition between the unburned and burned areas after the fires, the floristic composition of unburned area comprises: 79 families, 194 genera, 223 species, 26 varieties and 6 formae (255 kinds of vascular plants). The index of similary shows 0.77 (S$\Phi$renson:1948) in this area. The analyses of the life-form compositions in the unburned and burned area show 32.9% and 29.3% in dormancy form (H), 42.4% and 37.7% in disseminule form($D_1$), 80.8% and 82.2% in radicoid form ($R_5$), and 57.7% and 61.8% in erect form(e) respectively. The biological type shows H-$D_1$-R5-e, which is common in both areas, and erect form is generally prevailing in these communities.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.2
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• pp.369-376
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• 2021

The International Maritime Organization has developed the Energy Efficiency Design Index, an index related to carbon dioxide emissions, to enforce regulations on newly built ships. In this study, a new type of energy-saving device called the ring stator was used for 158k crude oil carriers, whose hull form was developed as a very thin after-body hull to reduce the resistance by delaying separation. The Energy-Saving Device (ESD) particularly involving the duct, is not adapted to the thin-after body hull form-like container ship. This new ring stator was developed considering these characteristics. A parametric study was conducted through Computational Fluid Dynamics (CFD) analysis using the Star-CCM+ program, and approximately 3.4 % improvement in propulsion efficiency was achieved. Further optimization investigations and experimental studies should be conducted in the future.

• Journal of the Korean GEO-environmental Society
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• v.15 no.2
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• pp.5-15
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• 2014

Target reliability index in the limit state design indicated the safety margin and it is important to determine the partial factor. To determine the target reliability index which is needed in the limit state design, the six design and construction case histories of gravel compaction piles (GCP) were investigated. The limit state functions were defined by bulging failure for the major failure mode of GCP. The reliability analysis were performed using the first order reliability method (FORM) and the reliability index was calculated for each ultimate bearing capacity formulation. The reliability index of GCP tended to be penportional to the safety factor of allowable stress design and average value was ${\beta}$=2.30. Reliability level that was assessed by reliability analysis and target reliability index for existing structure foundations were compared and analyzed. As a result, The GCP was required a relatively low level of safety compared with deep and shallow foundations and the currd t reliability level were similar to the target reliability in the reinforced earth retaining-wall and soil-nailing. Therefore the target reliability index of GCP suggested as ${\beta}_T$=2.33 by various literatures together with the computed reliability level in this study.

• Journal of the Korean Society of Clothing and Textiles
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• v.18 no.1
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• pp.130-139
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• 1994

This study was performed to provide the dress form for high school girls' clothing construction which can reflect the characteristics of their body. Two hundred and forty seven high school girls aged from 15 In 17 were directly measured. The results obtained from this study were as follows ; 1. High school girls' somatotype was similar to that of young adult women. They had the features of well developed upper trunk and well developed breadth, but less developed depth. 2. The correlation between length item and the other items was small enough to interpret that each item was independent. There was a Positive correlation between depth item and girth item. And, Observed correlation between weight and Rohrer's index and breadth, depth and girth item was much larger than expected, which showed that weight and Rohrer's index influenced on fatness factor. 3. Through factor analysis, six factors were extracted from anthropometric measurements. The first factor was representing upper body volumn which expressed the characteristics of somatotype better than any other factors, the second factor was breadth, the third factor was size, the fourth factor was length, the fifth was back shape and the sixth factor was shoulder shape. 4. For development of dress form for high school girls, directly anthoropometric measurements were used. The dress form constructed through this study represented the characteristics of high school girls, therefore this would be very useful to manufacture clothing for them in the future.

• Journal of Welding and Joining
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• v.8 no.1
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• pp.31-42
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• 1990

Arc must be stable during welding first of all other factors for obtaining sound weldment, especially in the automation of welding process. Arc stability is somewhat sophisticated phenomenon which is not clearly defined yet. In consumable electrode welding, the voltage and current variation due to metal transfer enables to assess arc stability. Recently, statistical analyses of the voltage and current waveform factors are performed to assess the degress of arc stability which is assessed and controlled by operator's own experience by now. But, considering the increasing need and the trend of automation of welding process, it is necessary to monitor arc stability in real-time. In this sutdy, the modified stability index composed of two voltage and current wvaeform factors (arc time and short circuit time) reduced from four factors (arc time, short circuit time, average arc current and average short circuit current) in Mita's index by the welding electrical circuit modeling is proposed and verified by experiments to be well estimating arc stability in the static sense. Also, the recursive calculation form estimating present arc stability in the dynamic sense is developed for real-time estimation. The results of applying the recursive index during welding show good estimation of arc stability in real-time. Therefore, the results of this study offers the mean for real-time control arc stability.