• The Journal of Bigdata
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• v.7 no.1
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• pp.125-137
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• 2022

The transportation industry is one of the important industries due to the geographical requirements surrounded by the sea on three sides of Korea and the problem of resource poverty, which relies on imports for most of its resource consumption. Among them, the proportion of the shipping industry is large enough to account for most of the transportation industry, and maintenance in the shipping industry is also important in improving the operational efficiency and reducing costs of ships. However, currently, inspections are conducted every certain period of time for maintenance of ships, resulting in time and cost, and the cause is not properly identified. Therefore, in this study, the proposed methodology, LSTM-AutoEncoder, is used to detect abnormalities that may cause ship failure by considering the time of actual ship operation data. In addition, clustering is performed through clustering, and the potential causes of ship main engine failure are identified by grouping outlier by factor. This enables faster monitoring of various information on the ship and identifies the degree of abnormality. In addition, the current ship's fault monitoring system will be equipped with a concrete alarm point setting and a fault diagnosis system, and it will be able to help find the maintenance time.

• Convergence Security Journal
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• v.22 no.1
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• pp.93-98
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• 2022

Information service technology continues to develop, and information service continues to expand based on the IT convergence trend. The premeter-based security model chosen by many organizations can increase the effectiveness of security technologies. However, in the premeter-based security model, it is very difficult to deny security threats that occur from within. To solve this problem, a zero trust model has been proposed. The zero trust model requires authentication for user and terminal environments, device security environment verification, and real-time monitoring and control functions. The operating environment of the information service may vary. Information security management should be able to response effectively when security threats occur in various systems at the same time. In this study, we proposed a security policy distribution system in the object reference method that can effectively distribute security policies to many systems. It was confirmed that the object reference type security policy distribution system proposed in this study can support all of the operating environments of the system constituting the information service. Since the policy distribution performance was confirmed to be similar to that of other security systems, it was verified that it was sufficiently effective. However, since this study assumed that the security threat target was predefined, additional research is needed on the identification method of the breach target for each security threat.

• The Journal of Bigdata
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• v.7 no.2
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• pp.153-172
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• 2022

Online shopping has transformed and rapidly grown the entire market at the forefront of wholesale and retail services as an effective solution to issues such as digital transformation and social distancing policy (COVID-19 pandemic). Small business owners, who form the majority at the center of the online shopping industry, are constantly collecting policy changes and market trend information to overcome these problems and use them for marketing and other sales activities in order to overcome these problems and continue to grow. Objective and refined information that is more closely related to the business is also needed. Therefore, in this paper, through the collection and analysis of big data information, which is the core technology of digital transformation, key variables are set in product classification, sales trends, consumer preferences, and review information of online shopping malls, and a method of using them for competitor comparison analysis and business sustainability evaluation has been prepared and we would like to propose it as a service. If small and medium-sized businesses can benchmark competitors or excellent businesses based on big data and identify market trends and consumer tendencies, they will clearly recognize their level and position in business and voluntarily strive to secure higher competitiveness. In addition, if the sustainable growth of the online shopping mall operator can be confirmed as an indicator, more efficient policy establishment and risk management can be expected because it has an improved measurement method.

• Analytical Science and Technology
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• v.20 no.4
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• pp.279-288
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• 2007

We have studied a method for the preparation of $ACF/TiO_2$ composites involving the penetrationof titanium n-butoxide (TNB) solution into activated carbon fiber. It was focused on the characterization of $TiO_2$ formed in prorous carbon was which increased with surface functional groups by hydrochloric acid treatment. The conversion of TNB to $TiO_2$ for the acid treatment effect must be important for the preparationof $ACF/TiO_2$ composites. From the characterization of surface properties, both the BET surface area and the total pore volume decreased as the distribution of $TiO_2$ on the activated carbon fiber surfaces after acid treatments.The changes in XRD pattern showed the typical anatase type on $ACF/TiO_2$ composite for the sample named FT, FT1 and FT2 treated with 0.05, 0.1 and 0.5 M, respectively. However, XRD patern of FT3 treated with 0.5M showed mixed amatase-rutile structure. According to the results of SEM micrographs, the titanium complexe particles were irregularly distributed around carbon. And some large clusters were found when an amount of acid treatment increased. The EDX results of $ACF/TiO_2$ composites showed the presence of C, O and P with strong Ti peaks. Finally, the excellent photocatalytic activity of the $ACF/TiO_2$ composites between relative concentration($c/c_o$) of MB (methylene blue) and UV irradiation time could be attributed to the both effects between photocatalysis of the formation of titania complexes and adsorptivity of the activated carbon fiber.

• Analytical Science and Technology
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• v.21 no.4
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• pp.284-295
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• 2008

For plastics samples, a method using combustion ion chromatography was selected as a method for rapid low-cost analysis to test whether hazardous substances are contained or not. Using combustion ion chromatography, a verification test for F, Cl and Br compounds generated a linear calibration curve with a correlation coefficient of $r^2$ = 0.999~1.000 in the calibration range from 0.5 to 4.0 mg/kg. The detection limits were found to be 0.005~0.024 mg/kg and quantitative limits were found to be 0.014~0.073 mg/kg. The recoveries of combustion ion chromatography using certified reference material (CRM) were found to be 95.5~104.9%. Based on these results, a proficiency test was conducted together with several laboratories in and out of the country, to make comparative analysis of the results from each laboratory. As a result, the data supported the use of combustion ion chromatography as an effective analysis method to deal with regulations for halogen-free electronic products and for other hazardous substances in the electronic products.

• The Journal of the Convergence on Culture Technology
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• v.9 no.3
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• pp.789-795
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• 2023

Digital-Twin are recognized as an important core technology for the realization of Smart Factories by simulating and optimizing the monitoring and predictive maintenance of manufacturing equipment and the operation of production lines in a digital space. To implement this system, we adopt the IEC62541-based OPC-UA (Open Platform Communications Unified-Architecture) Protocol, which has strengths in interoperability and connectivity between heterogeneous platforms. Therefore, In this paper, We designed and implemented an IIoT(Industry Internet of Things) system that connects heterogeneous platforms, and developed an OPC-UA simulator based on IEC 62541. We will present whether the data will be applied to the Digital-Twin Platform and whether it will work, and proceed with performance tests and evaluations. We evaluate the operation performance and OPC-UA performance of the Digital-Twin platform lightened by the proposed device, and present the optimal IEC62514-based simulator system. We proceeded with the performance evaluation of sending and receiving data with OPC-UA wrapping with the proposed simulator, and found that a lightweight Digital-Twin platform can be operated. This research can apply the OPC-UA protocol for implementing smart factory and meta-factory in the manufacturing shop floor with limited resources, avoiding the waste of time and space on the shop floor through the OPC-UA simulator. We expect that this will contribute to a significant improvement in efficiency by minimizing.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.2
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• pp.67-76
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• 2023

In this study, in order to enhance the joint capacity between the existing reinforced concrete (R/C) frame and the reinforcement member, we proposed a novel concept of Internal Composite Seismic Strengthening Method (CSSM) for seismic retrofit of existing domestic medium-to-low-rise R/C buildings. The Internal CSSM rehabilitation system is a type of strength-enhancing reinforcement systems, to easily increase the ultimate horizontal shear capacity of R/C structures without seismic details in Korea, which show shear collapse mechanism. Two test specimens of full-size two-story R/C frame were fabricated based on an existing domestic R/C building without seismic details, and then retrofitted by using the proposed CSSM seismic system; therefore, one control test specimen and one test specimen reinforced with the CSSM system were used. Pseudo-dynamic testing was carried out to evaluate seismic strengthening effects, and the seismic response characteristics of the proposed system, in terms of the maximum shear force, response story drift, and seismic damage degree compared with the control specimen (R/C bare frame). Experiment results indicated that the proposed CSSM reinforcement system, internally installed to the existing R/C frame, effectively enhanced the horizontal shear force, resulting in reduced story drift of R/C buildings even under a massive earthquake.

• Journal of the Korea Society of Computer and Information
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• v.28 no.4
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• pp.21-29
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• 2023

In this paper, we propose an AI-based system for automatically classifying industry and occupation codes in the population census. The accurate classification of industry and occupation codes is crucial for informing policy decisions, allocating resources, and conducting research. However, this task has traditionally been performed by human coders, which is time-consuming, resource-intensive, and prone to errors. Our system represents a significant improvement over the existing rule-based system used by the statistics agency, which relies on user-entered data for code classification. In this paper, we trained and evaluated several models, and developed an ensemble model that achieved an 86.76% match accuracy in industry and 81.84% in occupation, outperforming the best individual model. Additionally, we propose process improvement work based on the classification probability results of the model. Our proposed method utilizes an ensemble model that combines transfer learning techniques with pre-trained models. In this paper, we demonstrate the potential for AI-based systems to improve the accuracy and efficiency of population census data classification. By automating this process with AI, we can achieve more accurate and consistent results while reducing the workload on agency staff.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1C
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• pp.63-74
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• 2008

Site response analyses were performed based on equivalent linear technique using the local geologic and dynamic site characteristics, which include soil profiles, shear wave velocity profiles and depth to bedrock for 125 sites collected in Korean Peninsula. From the results of site response analyses, 2-parameters site classification system based on the combination of mean shear wave velocity of soil and depth to bedrock was newly recommended for regions of shallow bedrock depth in Korea. First, as the borders of bedrock depth (H) for site classification were determined as 10m and 20m, the soil sites were divided into 3 classes as $H_1$, $H_2$ and $H_3$ sites. And then, the 3 site classes were subdivided into 7 classes based on the mean shear wave velocity of soil ($V_{s,soil}$). The feasibility of new site classification system was verified and the representative site coefficients ($F_a$ and $F_v$) and design response spectrum were suggested by analyzing uniform trend and dispersion of site coefficients for each site class. The suggested site coefficients and the regression curves present the nonlinear characteristics of soils according to the change of rock outcrop acceleration with uniform trend effectively. From the comparison between the mean values of response spectrum which was acquired from the site response analysis and the suggested design response spectrum, there was a little difference in some of site classes and it was verified to adjust the integration interval to make it more suitable for the site condition in Korea.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.2B
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• pp.187-197
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• 2008

This study is to assess the impact of future land use change on hydrology and water quality in Gyungan-cheon watershed ($255.44km^2$) using SWAT (Soil and Water Assessment Tool) model. Using the 5 past Landsat TM (1987, 1991, 1996, 2004) and $ETM^+$ (2001) satellite images, time series of land use map were prepared, and the future land uses (2030, 2060, 2090) were predicted using CA-Markov technique. The 4 years streamflow and water quality data (SS, T-N, T-P) and DEM (Digital Elevation Model), stream network, and soil information (1:25,000) were prepared. The model was calibrated for 2 years (1999 and 2000), and verified for 2 years (2001 and 2002) with averaged Nash and Sutcliffe model efficiency of 0.59 for streamflow and determination coefficient of 0.88, 0.72, 0.68 for Sediment, T-N (Total Nitrogen), T-P (Total Phosphorous) respectively. The 2030, 2060 and 2090 future prediction based on 2004 values showed that the total runoff increased 1.4%, 2.0% and 2.7% for 0.6, 0.8 and 1.1 increase of watershed averaged CN value. For the future Sediment, T-N and T-P based on 2004 values, 51.4%, 5.0% and 11.7% increase in 2030, 70.5%, 8.5% and 16.7% increase in 2060, and 74.9%, 10.9% and 19.9% increase in 2090.