• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.3
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• pp.243-254
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• 2019

In this study, problems of the waterproofing methods in which water leakage occurs in the upper slab of the underground parking lot of apartment houses and the requirements considering the characteristics of the upper slab, and selected the appropriate performance(proposal) for the composite polyurea process are reviewed. As a result of the study, it is necessary to review performance such as responsiveness to upper slab of the multi-unit underground parking lot that is comprised of (1) crack and behavior responsiveness, (2) surface integrity, (3) vertical watertight stability, (4) pressure layer construction, (5) impact and pressure response and (6) vehicle moving load. As a result of evaluating 5 items corresponding to the requirements for the soft and hard complex polyurea, all of them were found to meet the conditions, and each materials were improved by compounding the materials that had problems when applying a single-ply method, thereby clarifying the advantages and disadvantages of the material property. However, in order to apply to the actual site, additional evaluation on site applicability such as mock-up evaluation should be conducted, and subsequent studies on the applicability of the market through review of economic feasibility and maintenance is required.

• Journal of Convergence for Information Technology
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• v.11 no.9
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• pp.17-27
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• 2021

The aim of this research was to identify the issue of the work permit system and consciousness of the people on the system, and to suggest some ideas on the government policies on it. To achieve the aim of research, this research used text mining based on social data. This research collected 1,453,272 texts from 6,217 units of online documents which contained 'work permit system' from January to December, 2020 using Textom, and did text-mining and social network analysis. This research extracted 100 key words frequently mentioned from the analyses of data top-level key word frequency, and degree centrality analysis, and constituted job problem, importance of policy process, competitiveness in the respect of industries, and improvement of living conditions of foreign workers as major key words. In addition, through semantic network analysis, this research figured out major awareness like 'employment policy', and various kinds of ambient awareness like 'international cooperation', 'workers' human rights', 'law', 'recruitment of foreigners', 'corporate competitiveness', 'immigrant culture' and 'foreign workforce management'. Finally, this research suggested some ideas worth considering in establishing government policies on the work permit system and doing related researches.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.5
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• pp.875-888
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• 2021

In this paper, we search integral distinguishers of lightweight block cipher PIPO and propose a key recovery attack on 8-round PIPO-64/128 with the obtained 6-round distinguishers. The lightweight block cipher PIPO proposed in ICISC 2020 is designed to provide the efficient implementation of high-order masking for side-channel attack resistance. In the proposal, various attacks such as differential and linear cryptanalyses were applied to show the sufficient security strength. However, the designers leave integral attack to be conducted and only show that it is unlikely for PIPO to have integral distinguishers longer than 5-round PIPO without further analysis on Division Property. In this paper, we search integral distinguishers of PIPO using a MILP-aided Division Property search method. Our search can show that there exist 6-round integral distinguishers, which is different from what the designers insist. We also consider linear operation on input and output of distinguisher, respectively, and manage to obtain totally 136 6-round integral distinguishers. Finally, we present an 8-round PIPO-64/128 key recovery attack with time complexity 2^124.5849 and memory complexity of 2⁹³ with four 6-round integral distinguishers among the entire obtained distinguishers.

• Korean Journal of Construction Engineering and Management
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• v.22 no.6
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• pp.120-130
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• 2021

Recently, the government is reinforcing safety management at construction sites to prevent safety accidents in construction works, and the safety management plan of workers is an important situation. Meanwhile, modular construction is expected to be gradually expanded to middle and high-rise buildings, but active measures to ensure worker safety are insufficient. This study is a preliminary study of the development of a checklist for preventive worker safety management. The purpose of this study is to derive a checklist classification system for the safety management of workers in the field of modular construction by preceding studies, case analysis, and expert advisory opinions. The classification system consists of large categories of factory manufacturing, transportation, and on-site construction, and the sub-system consists of six sub-classes: foundation work, frame work, modular frame installation work, finishing work, and facility work. Among them, the sub-classification of modular frame installation work consists of 12 unit works, centering on module lifting and assembly module work, which are the main construction processes. And the classification system reflects the three main management factors and contents for defined safety management. It is expected that the research results of this study can contribute to efficient safety management at the modular construction site.

• Journal of Technology Innovation
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• v.29 no.4
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• pp.161-196
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• 2021

This study presents a new methodology for developing AI-based products. It identifies the distinctive attributes of AI innovation that are different from existing methods, and presents a product design process and methodology reflecting these attributes. This study emphasizes that AI product development should be oriented toward an ambidexterity approach. This study proposes a design process and specific development method for AI-based products that including steps such as technology push oriented idea generation with morphological approach, market pull oriented consumer requirements analysis, product design refinement, etc. In order to verify the practical applicability of this methodology, an AI-based car infotainment system development strategy is derived as a case study. 13 innovative ideas were generated by the morphological approach and expert review based on technological possibility, and a total of 6 quality requirements were derived as new product development strategies through the analysis of consumer requirements by combining Kano and TOPSIS. The methodology proposed in this research paper can be usefully utilized for companies to pioneer new markets through AI-based products or to expand the market by upgrading existing products or services.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.611-620
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• 2021

The maintenance industry is mainly progressing based on condition-based maintenance after corrective maintenance and preventive maintenance. In condition-based maintenance, maintenance is performed at the optimum time based on the condition of equipment. In order to find the optimal maintenance point, it is important to accurately understand the condition of the equipment, especially the remaining useful life. Thus, using simulation data (C-MAPSS), a prediction model is proposed to predict the remaining useful life of a turbofan engine. For the modeling process, a C-MAPSS dataset was preprocessed, transformed, and predicted. Data pre-processing was performed through piecewise RUL, moving average filters, and standardization. The remaining useful life was predicted using principal component analysis and the k-NN method. In order to derive the optimal performance, the number of principal components and the number of neighbor data for the k-NN method were determined through 5-fold cross validation. The validity of the prediction results was analyzed through a scoring function while considering the usefulness of prior prediction and the incompatibility of post prediction. In addition, the usefulness of the RUL prediction model was proven through comparison with the prediction performance of other neural network-based algorithms.

• Korean Journal of Social Welfare Studies
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• v.48 no.3
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• pp.57-81
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• 2017

As of the end of the year 2016, the foreigners staying in Korea have surpassed 2 million people for the very first time ever since the statistical writings began. Because the inflow of the foreigners has been greatly increased within a short time period, the Korean society has been rapidly changing into a multi-racial and multi-ethnic society, and the children of the multicultural families, too, have been increasing gradually. Because of the social prejudices, discriminations, negative recognitions, etc., the children of the multicultural families get exposed to the diverse problems. It can be considered that such social prejudices and negative recognitions comprise the discourses that are possessed by the constituent members of the society regarding a certain subject or phenomenon. By analyzing the special characteristics and discourses of the reports on the multicultural children and youths by the Korean press through newspaper articles, this research confirmed what influences the media have in the process of forming the recognitions regarding the multicultural children and youths at present. As a result of the research, the discourses appearing in the newspapers could be typed into the support emphasizing frame of the Korean society, the adaptation emphasizing frame of the Korean society, the global people of talent frame, the change emphasizing frame of the Korean society, and the social problem emphasizing frame. Based on such research results, I made a proposal regarding the direction for the desirable reports by the media.

• Journal of Internet Computing and Services
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• v.20 no.3
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• pp.43-59
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• 2019

Today, with the spread of smartphones and the development of social networking services, structured and unstructured big data have stored exponentially. If we analyze them well, we will get useful information to be able to predict data for the future. Large amounts of data need to be collected first in order to analyze big data. The web is repository where these data are most stored. However, because the data size is large, there are also many data that have information that is not needed as much as there are data that have useful information. This has made it important to collect data efficiently, where data with unnecessary information is filtered and only collected data with useful information. Web crawlers cannot download all pages due to some constraints such as network bandwidth, operational time, and data storage. This is why we should avoid visiting many pages that are not relevant to what we want and download only important pages as soon as possible. This paper seeks to help resolve the above issues. First, We introduce basic web-crawling algorithms. For each algorithm, the time-complexity and pros and cons are described, and compared and analyzed. Next, we introduce the state-of-the-art web crawling algorithms that have improved the shortcomings of the basic web crawling algorithms. In addition, recent research trends show that the web crawling algorithms with special purposes such as collecting sentiment words are actively studied. We will one of the introduce Sentiment-aware web crawling techniques that is a proactive web crawling technique as a study of web crawling algorithms with special purpose. The result showed that the larger the data are, the higher the performance is and the more space is saved.

• Journal of Climate Change Research
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• v.3 no.1
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• pp.25-37
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• 2012

This research proposes the direction for the assessment of local government infrastructure vulnerabilities relating to climate change driven flood and analyzes the assessment result. In this research, the local government infrastructures are evaluated by three indices such as exposure, infrastructure sensitivity, adaptive capacity and each index is calculated by selected alternative variable. Climate change scenario(A1B) developed on National Institute of Environmental Research is used to calculate present and future(2020, 2050, 2100s) exposure. As the result of infrastructure vulnerability assessment on present, the infrastructures in Seoul, Northern Gyeonggi-do, Gangwon-do, coastal area of Gyeongsangnam-do are vulnerable to flooding. For future, although the spatial pattern of flooding vulnerable infrastructure are similar, the flooding vulnerabilities of infrastructure in Gyeonggido and Ganwon-do would be increased as close to 2100s. It is expected that this research can be utilized as the preliminary analysis for climate change adaptation in local government infrastructure because this research propose the method for the assessment of local government infrastructure vulnerability relating to climate change driven flood and the result such as a trend of infrastructure vulnerability to flooding and the level of contribution of each index and alternative variable.

• 재활복지
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• v.20 no.3
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• pp.17-43
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• 2016

This study is on understanding the reality of disabled seniors and investigation of factors that affect overall life satisfaction, making a proposal to improve their life quality. Situation data for the disabled, gathered by Korea Institute for Health and Social Affairs (KIHASA) in 2014, was used to perform the study, and the target group is 3,181 people with disability, above the age of 65. Descriptive statistics was presented for data analysis and logistic regression analysis was performed to investigate factors that affect life satisfaction. It was concluded from the analysis that gender, age, presence of spouse (demographic factors), house income, possession of house, presence of pensioner, registration to public pension plan, social discrimination (social-economical factors), level of disability, subjective health status, level of help needed for daily living, presence of care-giver, sufficiency of help, ability to go out by oneself, difficulty of using public transportations, and presence of medical checkups (disability and health factors.) make meaningful effects to life satisfaction of disabled seniors. Based on the derived results, this study suggests intensive interests and care-giving service for disabled seniors that live alone, institutional complementations to guarantee income security, including public or private pensions, improvements to social recognition and environments for discrimination of the disabled, organization of health and medical treatment service and health care system, comprehensive service provision to social welfare for both the disabled and seniors, and comprehensive service provision to both health care and social welfare.