• 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.

• Korean Journal of Construction Engineering and Management
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• v.23 no.5
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• pp.3-14
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• 2022

Construction projects have high potentials of claims among a variety of stakeholders. Claims on their own are not disputes but they have high potentials leading to disputes if agreements are not made between parties due to conflicting opinions. In the event of the construction disputes between clients and contractors, it could give negative impacts to both parties and, to minimize or pro-actively manage construction disputes, the role of clients is more significant. The objective of the study is to analyze a level of associations between the types of disputes and causes of construction projects based on the association rule analysis, and to identify and discuss key characteristics and implications from client's perspectives. The study analyzes associations between the types of disputes and causes, and also identifies those with a high level of associations. It also presents the outcomes of more systematic analysis compared to descriptive statistics just based on frequencies. Through the analysis of the data cases, the study proposes the directions to resolve the causes of disputes from client's perspectives. It can assist to improve understandings of the relationships between the types of disputes and causes and to pro-actively manage the disputes of construction projects.

• Journal of Korea Water Resources Association
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• v.55 no.4
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• pp.267-278
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• 2022

Recently Flood damage volume has increased as heavy rain has frequently occurred. Especially urban areas are a vulnerability to flooding damage because of densely concentrated population and property. A local government is preparing to mitigate flood damage through the heavy rain warning issued by Korea Meteorological Administration. This warning classification is identical for a national scale. However, Seoul has 25 administrative districts with different regional characteristics such as climate, topography, disaster prevention state, and flood damage severity. This study considered the regional characteristics of 25 administrative districts to analyze the flood vulnerability using entropy weight and Euclidean distance. The rainfall classification was derived based on probability rainfall and flood damage rainfall that occurred in the past. The result shows the step 2 and step 4 of rainfall classification was not significantly different from the heavy rain classification of the Korea Meteorological Administration. The flood vulnerability is high with high climate exposure and low adaptability to climate change, and the rainfall classification is low in the northern region of Seoul. It is possible to preemptively respond to floods in the northern region of Seoul based on relatively low rainfall classification. In the future, we plan to review the applicability of rainfall forecast data using the rainfall classification of results from this study. These results will contribute to research for preemptive flood response measures.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.2
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• pp.271-276
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• 2020

In terms of supply of manpower in the energy industry, domestic universities cannot realistically operate flexibly to meet manpower demand in accordance with various regulations related to the department, and there are only a few independent energy related departments. There are many difficulties in closure, increase and decrease of capacity, and foster convergence. In addition to the limited aspects of human resource development of universities, changes in the energy paradigm, namely: 1) changes in the energy industry from stable supply and energy security to new growth engines and export industries, 2) Revitalization of the energy industry, 3) including diversification of energy sources and the spread of new technologies. Therefore, in this paper, we propose a training program for nurturing new renewable energy specialists to independently develop various high-quality human resources such as intangible and convergent human resources in line with changes in the energy paradigm.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.6
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• pp.843-852
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• 2022

Despite continuous safety management, the death rate of construction workers is not decreasing every year. Accordingly, various studies are in progress to prevent construction site accidents. In this paper, we developed an AI-based priority inspection target selection model that preferentially selects sites are expected to cause construction accidents among construction sites with construction costs of less than 5 billion won (KRW). In particular, Random Forest (90.48 % of accident prediction AUC-ROC) showed the best performance among applied AI algorithms (Classification analysis). The main factors causing construction accidents were construction costs, total number of construction days and the number of construction performance evaluations. In this study an ROI (return of investment) of about 917.7 % can be predicted over 8 years as a result of better efficiency of manual inspections human resource and a preemptive response to construction accidents.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.331-337
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• 2021

Owing to the limited development period and budget of the weapon system, many problems have arisen in the operation stage after mass production. Therefore, engineering changes are also increasing. On the other hand, an analysis of the cause of problems and improvement of the system equipment performed in engineering changes cannot be managed synthetically. Hence, important actual data can only be used once. In particular, unlike hardware where the shape of the equipment is changed or the part number is changed, the contents of software engineering changes are only partially included in the proposal. Moreover, only the extent to which the version of the source package and the executable file has been changed can be identified. Therefore, this paper proposes a method to build and utilize a database for cause analysis and improvement plan data of weapon-system software engineering changes and software technical support. The above utilization measure can contribute to the quality assurance of weapon-system software developed in the future by preemptively applying real-world data when developing similar weapon systems.

• Clinical and Experimental Pediatrics
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• v.49 no.2
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• pp.173-180
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• 2006

Purpose : Cytomegalovirus(CMV) infection still remains as a major cause of morbidity and mortality after stem cell transplantation. In this study, we analyzed the results of antigenemia-guided preemptive therapy among children with allogeneic hematopoietic stem cell transplantation to determine the incidence and risk factors associated with CMV antigenemia, and evaluated the efficacy of the CMV antigenemia based preemptive therapy. Methods : We enrolled 213 pediatric patients following allogeneic hematopoietic stem cell transplantation(HSCT), at the Catholic HSCT center between October 1998 and December 2003. Pre-emptive ganciclovir was started when more than 5 CMV Ag-positive cells were detected in matched sibling HSCT, and when any Ag-positive cells were seen in unrelated allogenic HSCT. Results : CMV antigenemia was observed in 88(41.3 percent) of 213 patients on median day 28(day 11-99). In univariated analysis, use of unrelated donors(other than siblings), age of recipient(more than 5 years at transplant) at transplantation, the presence of recipient CMV-IgG before transplantation, TBI-based conditioning regimen and the presence of acute GvHD(grade ${\geq}II$) were the risk factors for positive CMV antigenemia. In multivariate analysis, unrelated bone marrow transplantation, positive recipient CMV serology and acute GvHD(grade ${\geq}II$) were the independent risk factors for positive CMV antigenemia. Conclusion : Risk factors of CMV infection in children were CMV serostatus of the recipient, the source of stem cells, and acute graft-versus-host disease. The pre-emptive therapy based on CMV antigenemia was effective in the prevention of CMV disease.

• Journal of the Economic Geographical Society of Korea
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• v.13 no.4
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• pp.548-560
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• 2010

This study aims to estimate the payment of farmland reverse mortgage(FRM) and to explore policy considerations about the restructuring of rural area after the initiation of farmland reverse mortgage. Farmland reverse mortgage provides stable monthly income basement for the welfare of rural elderly by liquidating fixed asset such as farmlands which the elderly in rural area owns. The main results of this study can be summarized as follows. First, FRM model based on Housing Equity Conversion Model, which is suggested by Rodda et al (2003), was built. Then, critical factors like farmland value rising rates and interest rates were elaborated, and affordable and proper monthly payment were estimated. 246,982 won, 419,374 won and 757,379 won is given to the borrower at age 65, 75 and 85 respectively with 100,000,000 won value farmland. Second, policy considerations which are necessary for the successful launch of FRM, and restructuring of rural area after launching FRM were discussed. Three policy considerations were proposed. First is about the integrated asset management system for rural elderly people. Second is about the reasonable settlement of corporate farmers system. And third is about the preparations for rural land use planning.

• The Journal of the Korea Contents Association
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• v.19 no.10
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• pp.315-324
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• 2019

In this research, one of five Hofstede's cultural dimension, Long term orientation (LTO) was selected to examine its influence on individual's change oriented organizational citizenship behavior with emotional regulation mediating. East Asian countries and Korea especially received higher score on LTO cultural dimension, meaning it valued harmony, long term relations and saving for future. Also, in today's hyper competitive and evolving global climate, the ability to adapt quickly and also to be able to control one's emotion is highly valued individual competency. Previous research on Hofstede's cultural dimensions were conducted at mostly national or large group levels. However, in this study, Yoo's CVSCALE which allowed for individual level analysis on Hofstede's cultural dimensions were used to analyze multinational company's employees's long term orientations' influence on emotional regulation and change oriented organizational citizenship behavior. The survey conducted from 200 employees from major electronic company based in S city in Korea for two weeks period and the results indicated long term orientation positively influenced change oriented organizational citizenship behavior. Also emotional regulation mediated between long term orientation felt by individuals and change oriented organizational citizenship behavior. Such results validated previous studies that indicated emotional regulation as possible antecedents of individual proactive behaviors such as change organizational citizenship behavior and long term oriented view as another potential antecedent of change oriented organizational citizenship behavior in multinational corporation setting.

• Journal of Aerospace System Engineering
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• v.10 no.4
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• pp.67-74
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• 2016

The primary aim for using a Korean Condition Based Maintenance (CBM) system is to maintain military operational readiness using Interactive Collection Analysis Systems (ICAS) installed on naval vessels. Other aims are to preemptively provision maintenance and supply functions, to guarantee economical management of logistical assets, and to implement data driven equipment life cycle management. In order to accomplish these aims, it is necessary to establish standard system conditions. However, because manufacturers do not provide the technology necessary for maintenance management, it is required to retain component performance maps for each piece of equipment, and to accumulate data about frequently occurring fault patterns. This study confirms the validity of component performance maps using micro gas turbines and provides accumulated data on machine break downs. This would allow real time equipment performance checks and present performance trends. Then analysis would provide solutions for maintaining the best machine operating conditions with detailed maintenance manuals for operators. This study is a basis for further research to investigate additional ways to develop CBM using data obtained from naval vessels used in actual military operations.