• Journal of the Korean Geographical Society
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• v.49 no.1
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• pp.32-44
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• 2014

This study aimed to analyze the characteristic of the distribution of minimum temperature during January in the central region of South Korea and to investigate causes for the occurrence of extreme minimum temperature in Cheorwon. January temperature distribution data which were collected from 25 weather stations in central area from 1991 to 2010 were investigated, and the difference of temperature between Cheorwon and the other stations in central region, such as Chuncheon, Hongcheon, Bonghwa, Daegwallyoung, Wonju and Jecheon were analyzed by the type of atmospheric pressure system. Daily mean temperature and mean of daily minimum temperature appear to be low at Cheorwon and at the sites in high altitudes, but the frequency of extreme cold wave such as below $-15^{\circ}C$ is also noticeable in Cheorwon. When the Siberian High has expanded and migratory anticyclone has moved onto the north of the Korean Peninsula, the temperature at Cheorwon is relatively low. Furthermore it shows a lesser difference between Cheorwon and the compared stations when the migratory anticyclone affected the area, even at basin like Bonghwa, Jecheon more lower than Cheorwon.

• Journal of the Korean earth science society
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• v.26 no.6
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• pp.560-572
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• 2005

This study investigates the characteristics of atmospheric circulation and the heat source $(Q_1)$ related to the winter cold surge in Korea from 1979 to 1999. The occurrence frequency of cold surge is about one event per year and $60\%$ of the total events occurred during the former period, before 1989. During the cold surge, the pressure pattern shows more dominant east-west dipole circulation pattern in the lower troposphere and the effect of upper level trough is stronger than normal cases. Temperature falling pattern over Korea shows that the pattern opposite to the temperature structure over Lake Baikal and temperature change has opposite signs between the low-middle level and upper level, with the boundary at 400 hPa. The analysis of heat source shows that atmospheric cooling by cold advection during the cold surge is balanced by adiabatic warming due to downward motion, indicating that the movement path of cold core is associated with that of heat sink. Therefore, the movement mechanism of the heat source and sink should be well known for understanding the maintenance mechanism of cold surge and predicting cold surges.

• The Journal of Engineering Geology
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• v.6 no.2
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• pp.59-64
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• 1996

Acoustic Emission(AE) signals are emitted by a sudden release of strain energy associated with material damage. A multi-channels of LeCroy system and piezoelectric pressure transducers are employed for AE measurement to investigate the roles of AE in the propagation of macro cracks as well as the characteris-tics of AE wave in occurrence, amplitude and dominant frequency with changes in macro loading modes. Deduced crack opening volume of micro cracks varied widely and implies that AE events could be caused by crystal dislocations on a small scale and grain boundary movements on a large scale. Amplitude of first arrival AE wave emitted during mode I test was approximately 3 times higher than those from mixed mode test, while the number of AE count in mode I test was only 25% of mixed mode. It may imply that the total energy required for generation of a given fracture surface is similar regardless in change of macroloading modes.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.1
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• pp.169-174
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• 2018

There are many CCTV cameras connected to the video surveillance and monitoring center for the safety of citizens, and it is difficult for a few monitoring agents to monitor many channels of videos. In this paper, we propose an intelligent video surveillance system utilizing a safety map to efficiently monitor many channels of CCTV camera videos. The safety map establishes the frequency of crime occurrence as a database, expresses the degree of crime risk and makes it possible for agents of the video surveillance center to pay attention when a woman enters the crime risk area. The proposed gender classification method is processed in the order of pedestrian detection, tracking and classification with deep training. The pedestrian detection and tracking uses Adaboost algorithm and probabilistic data association filter, respectively. In order to classify the gender of the pedestrian, relatively simple AlexNet is applied to determine gender. Experimental results show that the proposed gender classification method is more effective than the conventional algorithm. In addition, the results of implementation of intelligent video security system combined with safety map are introduced.

• Journal of the Ergonomics Society of Korea
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• v.27 no.1
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• pp.45-51
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• 2008

The purpose of this survey was to identify ergonomic risk factors of work-related musculoskeletal disorders (MSD) and understand the current MSD risk status in the wholesale/retail industry. The field survey was conducted at 120 wholesale/retail establishments, and the cause of MSD occurred from the national industrial accident statistics by the Ministry of Labor in 2006 was analyzed in terms of company size, a term of work, job title, and cause of occurrence. The numbers of disasters on MSD were 602 which were included 432 disasters who met with low back pain by incident. A checklist was developed by KOSHA to use for the field survey. A total of 419 tasks were identified at the 120 establishments surveyed. The highest frequency was Task 2(45%) which was mostly observed in repetitive work (e.g. displaying, scanning, cutting or wrapping of goods). The second and third were Task 9(34%) and Task 8(14%) which were identified in manual materials handling (e.g. lifting, lowering, carrying or stocking of goods). The results suggest that the three Tasks should be first considered for the control in wholesale/retail industry and that exposure to MSD risk factors in those Tasks should be primarily addressed in order to reduce MSD risk in that industry.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.12
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• pp.1040-1047
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• 2012

This paper presents a fault diagnosis algorithm of control surfaces of small fixed-wing aircraft to reduce maintenance cost or to improve repair efficiency by estimation of fault occurrence or part replacement periods. The proposed fault diagnosis algorithm consists of ANPSD (Averaged Normalized Power Spectral Density), PCA (Principle Component Analysis), and GC (Geometric Classifier). ANPSD is used for frequency-domain vibration testing. PCA has advantage to extract compressed information from ANPSD. GC has good properties to minimize errors of the fault detection and isolation. The algorithm was verified by the accelerometer measurements of the scaled normal and faulty ailerons and the test results show that the algorithm is suitable for the detection and isolation of the control surface faults. This paper also proposes solutions for some kind of implementation problems.

• The Journal of Information Systems
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• v.30 no.1
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• pp.123-149
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• 2021

Purpose The purpose of this study is to define the anti-ESG activities of companies recognized by media by reflecting ESG recently attracted attention. This study extracts keywords for ESG controversies through association rule mining. Design/methodology/approach A research framework is designed to extract keywords for ESG controversies as follows: 1) From DeepSearch DB, we collect 23,837 articles on anti-ESG activities exposed to 130 media from 2013 to 2018 of 294 listed companies with ESG ratings 2) We set keywords related to environment, social, and governance, and delete or merge them with other keywords based on the support, confidence, and lift derived from association rule mining. 3) We illustrate the importance of keywords and the relevance between keywords through density, degree centrality, and closeness centrality on network analysis. Findings We identify a total of 26 keywords for ESG controversies. 'Gapjil' records the highest frequency, followed by 'corruption', 'bribery', and 'collusion'. Out of the 26 keywords, 16 are related to governance, 8 to social, and 2 to environment. The keywords ranked high are mostly related to the responsibility of shareholders within corporate governance. ESG controversies associated with social issues are often related to unfair trade. As a result of confidence analysis, the keywords related to social and governance are clustered and the probability of mutual occurrence between keywords is high within each group. In particular, in the case of "owner's arrest", it is caused by "bribery" and "misappropriation" with an 80% confidence level. The result of network analysis shows that 'corruption' is located in the center, which is the most likely to occur alone, and is highly related to 'breach of duty', 'embezzlement', and 'bribery'.

• Journal of Information Science Theory and Practice
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• v.10 no.3
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• pp.40-56
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• 2022

This paper aims to implement a topic modeling technique for extracting the topics of online discussions among library professionals in India. Topic modeling is the established text mining technique popularly used for modeling text data from Twitter, Facebook, Yelp, and other social media platforms. The present study modeled the online discussions of Library and Information Science (LIS) professionals posted on Lis Links. The text data of these posts was extracted using a program written in R using the package "rvest." The data was pre-processed to remove blank posts, posts having text in non-English fonts, punctuation, URLs, emails, etc. Topic modeling with the Latent Dirichlet Allocation algorithm was applied to the pre-processed corpus to identify each topic associated with the posts. The frequency analysis of the occurrence of words in the text corpus was calculated. The results found that the most frequent words included: library, information, university, librarian, book, professional, science, research, paper, question, answer, and management. This shows that the LIS professionals actively discussed exams, research, and library operations on the forum of Lis Links. The study categorized the online discussions on Lis Links into ten topics, i.e. "LIS Recruitment," "LIS Issues," "Other Discussion," "LIS Education," "LIS Research," "LIS Exams," "General Information related to Library," "LIS Admission," "Library and Professional Activities," and "Information Communication Technology (ICT)." It was found that the majority of the posts belonged to "LIS Exam," followed by "Other Discussions" and "General Information related to the Library."

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.3
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• pp.371-380
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• 2023

Currently, as construction projects in Korea are becoming larger and more complex, the hazard rate of the construction industry is steadily increasing, contrary to other industries. This can be seen as an indication that the safety technology and safety consciousness of construction workers are insufficient compared to the improved construction technology. In addition, due to the characteristics of the construction industry based on manpower, most accidents appear in conventional forms such as fall and trip due to human errors. Therefore, analyzing the relationship between the characteristics of human resources and accidents and establishing detailed safety plans is an essential part of reducing construction accidents. In this study, a correlation analysis was conducted using 62,805 cases of construction accident cases over 3 years to derive the characteristics of accident occurrence focusing on the age of workers. As a result of the analysis, the relationship between the age of workers and the frequency and severity of accidents for each accident type was derived, focusing on the top 10 accident types.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.2
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• pp.133-140
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• 2009

In order to examine the effects of micrometeorological and climatological influences on urban scale particulate air pollutants observed in Busan, power spectrum analysis was applied to the observed particulate matter with aerodynamic diameter ${\le}10{\mu}m$ ($PM_{10}$) for the period from 1991 to 2006. Power spectrum analysis has been employed to the daily mean $PM_{10}$ concentrations obtained at 13 sites to identify different scales of periodicities of $PM_{10}$ concentrations. The results show that, aside from the typical and well-known periodicities such as diurnal and annual variations caused by anthropogenic emission influences, another two significant peaks of power spectrum density were identified: 21 day and $3{\sim}4$ year of periodicities. Cospectrum analysis indicates that the intraseasonal 21 day periodicity are found to be negatively correlated with wind speed and surface pressure but shows consistently positive with relative humidity and temperature. This result implied that 21 day periodicity is presumably relevant to the secondary aerosol formation processes through the photochemical reaction that can be subsequently resulted from hygroscopic characteristics of aerosol formation. However, the interannual $3{\sim}4$ year of periodicity is found to have positive correlation with pressure, and negative with temperature and relative humidity, which is rather consistent with both characteristics of air mass during the Asian dust event and the occurrence frequency of Asian dust whose periodicities have been recorded inter-annually over the Korean peninsula.