• Korean Journal of Construction Engineering and Management
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• v.6 no.4 s.26
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• pp.80-90
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• 2005

Activity durations retain probabilistic and stochastic natures due to diverse factors causing the delay or acceleration of activity completion. These natures make the final project duration to be a random variable. These factors are the major source of financial risk. Extending the Stochastic Project Scheduling Simulation system (SPSS) developed in previous research; this research presents a method to estimate how the final project duration behaves when activity durations change randomly. The final project cost is estimated by considering the fluctuation of indirect cost, which occurs due to the delay or acceleration of activity completion, along with direct cost assigned to an activity. The final project cost is estimated by considering how indirect cost behaves when activity duration change. The method quantifies the amount of contingency to cover the expected delay of project delivery. It is based on the quantitative analysis to obtain the descriptive statistics from the simulation outputs (final project durations). Existing deterministic scheduling method apply an arbitrary figures to the amount of delay contingency with uncertainty. However, the stochastic method developed in this research allows computing the amount of delay contingency with certainty and certain degree of confidence. An example project is used to illustrate the quantitative analysis method using simulation. When the statistical location and shape of probability distribution functions defining activity durations change, how the final project duration and cost behave are ascertained using automated sensitivity analysis method

• Journal of Korea Port Economic Association
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• v.28 no.1
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• pp.143-157
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• 2012

By strengthening the market control and expanding the networks, providers of global logistics are expanding their service scope. The warehouses connect networks to internal and external warehouses by using logistics providers. The paper focuses on analyzing the efficiency of warehouses on each district. Therefore, the study classifies the factors which specify the efficiency of a total logistics of warehouse industry and warehouses' employees and the number of warehouses on district. Furthermore, the most recently published reports by National Center for Statistics in 2012 was used in order to guarantee credibility of the study. This study utilizes five years of materials, which are from 2005 to 2009. By applying SBM (Slack Based Measure), DEA Window model, and the Malmquist productivity model, the trend in efficiency and stableness were analyzed. The principal purpose of the paper is evaluating the efficiency. Also, analyzing its determinants and illustrating a long-term relationship between the regional warehouses and annual turnover of the warehouses were used as output measures. In addition, the number of warehouses of each region, employees, warehouses equipments, and the Logistics Warehouses Providers were used as input measurements. As a result, Malmquist productivity model and annual stableness has shown a continuous increasing. Ultimately, to be approved as product of Korea, a new stratiges that meet the standards and Rules of Origins by FTA should be developed. Therefore, there must be a development that takes regional characteristics into consideration.

• Journal of Intelligence and Information Systems
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• v.29 no.4
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• pp.347-373
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• 2023

As the significance of ESG (Environmental, Social, and Governance) management amplifies in driving sustainable growth, this study delves into and compares ESG trends and interrelationships from both corporate and societal viewpoints. Employing a combination of Latent Dirichlet Allocation Topic Modeling (LDA) and Semantic Network Analysis, we analyzed sustainability reports alongside corresponding social media datasets. Additionally, an in-depth examination of social media content was conducted using Joint Sentiment Topic Modeling (JST), further enriched by Semantic Network Analysis (SNA). Complementing text mining analysis with the assistance of ChatGPT, this study identified 25 different ESG topics. It highlighted differences between companies aiming to avoid risks and build trust, and the general public's diverse concerns like investment options and working conditions. Key terms like 'greenwashing,' 'serious accidents,' and 'boycotts' show that many people doubt how companies handle ESG issues. The findings from this study set the foundation for a plan that serves key ESG groups, including businesses, government agencies, customers, and investors. This study also provide to guide the creation of more trustworthy and effective ESG strategies, helping to direct the discussion on ESG effectiveness.

• Journal of Intelligence and Information Systems
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• v.24 no.1
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• pp.183-203
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• 2018

News articles are the most suitable medium for examining the events occurring at home and abroad. Especially, as the development of information and communication technology has brought various kinds of online news media, the news about the events occurring in society has increased greatly. So automatically summarizing key events from massive amounts of news data will help users to look at many of the events at a glance. In addition, if we build and provide an event network based on the relevance of events, it will be able to greatly help the reader in understanding the current events. In this study, we propose a method for extracting event networks from large news text data. To this end, we first collected Korean political and social articles from March 2016 to March 2017, and integrated the synonyms by leaving only meaningful words through preprocessing using NPMI and Word2Vec. Latent Dirichlet allocation (LDA) topic modeling was used to calculate the subject distribution by date and to find the peak of the subject distribution and to detect the event. A total of 32 topics were extracted from the topic modeling, and the point of occurrence of the event was deduced by looking at the point at which each subject distribution surged. As a result, a total of 85 events were detected, but the final 16 events were filtered and presented using the Gaussian smoothing technique. We also calculated the relevance score between events detected to construct the event network. Using the cosine coefficient between the co-occurred events, we calculated the relevance between the events and connected the events to construct the event network. Finally, we set up the event network by setting each event to each vertex and the relevance score between events to the vertices connecting the vertices. The event network constructed in our methods helped us to sort out major events in the political and social fields in Korea that occurred in the last one year in chronological order and at the same time identify which events are related to certain events. Our approach differs from existing event detection methods in that LDA topic modeling makes it possible to easily analyze large amounts of data and to identify the relevance of events that were difficult to detect in existing event detection. We applied various text mining techniques and Word2vec technique in the text preprocessing to improve the accuracy of the extraction of proper nouns and synthetic nouns, which have been difficult in analyzing existing Korean texts, can be found. In this study, the detection and network configuration techniques of the event have the following advantages in practical application. First, LDA topic modeling, which is unsupervised learning, can easily analyze subject and topic words and distribution from huge amount of data. Also, by using the date information of the collected news articles, it is possible to express the distribution by topic in a time series. Second, we can find out the connection of events in the form of present and summarized form by calculating relevance score and constructing event network by using simultaneous occurrence of topics that are difficult to grasp in existing event detection. It can be seen from the fact that the inter-event relevance-based event network proposed in this study was actually constructed in order of occurrence time. It is also possible to identify what happened as a starting point for a series of events through the event network. The limitation of this study is that the characteristics of LDA topic modeling have different results according to the initial parameters and the number of subjects, and the subject and event name of the analysis result should be given by the subjective judgment of the researcher. Also, since each topic is assumed to be exclusive and independent, it does not take into account the relevance between themes. Subsequent studies need to calculate the relevance between events that are not covered in this study or those that belong to the same subject.

• Journal of The Korean Association For Science Education
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• v.41 no.6
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• pp.455-470
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• 2021

This study examines the trend changes in keywords and topics of STEAM education from 2009 to 2020 to derive future development direction and education implications. Among the collected data, 42 cases of Ministry of Education's documents, 1,534 cases of articles, and 880 cases of abstract of researches were selected as research subjects. Keyword analysis, keyword network and topic modeling were performed for each stage of STEAM education policy through the Python program. As a result of the analysis, according to the STEAM education policy stage, there were differences in the frequency and network of keywords related to STEAM education by media. It was confirmed that there was a difference in interest in STEAM education policy as there were differences in keywords and topics that were mainly used importantly by media. Most of the topics of the Ministry of Education's documents were found to correspond to topics derived from articles. The implications for the development direction of STEAM education derived from the results of this study are as follows: first, STEAM education needs to consider ways to connect multiple topics, including the humanities. Second, since the media has a difference in interest in STEAM education policy, it is necessary to seek a cooperative development direction through understanding this. Third, the Ministry of Education's support for core competency reinforcement and convergence literacy for nurturing future talents, the goal of STEAM education, and the media's efforts to increase the public's understanding of STEAM education are required. Lastly, it is necessary to continuously analyze the themes that will appear in the evaluation process and change STEAM education policy.

• Journal of Digital Convergence
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• v.15 no.10
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• pp.123-132
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• 2017

In order to identify the factor and effect of shippers' inland transportation decision in North China and the Republic of Korea, the determinants of shipping liners, shippers and forwarders when selecting ports were extracted through previous studies and then analyzed using factor analysis and Fuzzy-AHP. As a result of analyzing the importance between groups, it can be found that while logistics costs at port and accessibility to hinterland are the most important factors for shipping liners, shippers and forwarders. Transportation cost by feeder is the most important sub factors for shipping liners. Inland transportation cost is the most important sub factors for shippers and forwarders. Through this study, it was recognized that one of the biggest concerns of shippers was reduction of inland transportation cost In addition, it was confirmed that the main factor of shifting the decision of the port selection from the shipping liners to the shipper is the reduction of inland transportation cost.

• Korean Journal of Construction Engineering and Management
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• v.18 no.1
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• pp.58-64
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• 2017

Construction Management (CM) is being utilized as an efficient project management system. Construction management system provide scientific management techniques as well as the expert's service with the expertise. Accordingly, CM services demand is continuously increasing in construction project. Construction Management engineer grade is distinguished by the Index of Construction Engineer's Competency (ICEC). Construction management engineer requires a higher score than the other fields. However, junior grade CM engineer can get grade according to the education and qualification. This study was conducted junior grade CM engineer depth interview after analyzing the problem of the current CM engineer grade system. As a result, this study was to extracted the 23 kind competence factors. And, competence factors were five area grouped using affinity diagram method. Next, we analyzed the importance utilizing the Analytic Network Process (ANP) technique. As a result, high priority areas were analyzed to be quality and cost areas associated with project management.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.3
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• pp.326-333
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• 2015

A tidal sandshoal, called 'Puldeung' in the Daeijackdo Marine Protected Area(DMPA), is facing erosion due to sand mining in the nearby coastal region. To monitor the morphologic change and erosion of Puldeung, a camera monitoring system was established at the top of Song-Ee Mountain in Daeijack Island. The system consists of 2 Cannon digital cameras, Eye-fi memory card/Long-Term Evolution wireless network, and solar power supply. The acquired camera images were analyzed to obtain the area of Puldeung by the following methods: geometric correction of image, identification of shoreline, areal measurement of Puldeung and its error estimation. To compare the Puldeung area with previously measured area of 1.79 km2 at tidal height of 137 cm in 2008 and of 1.59 km2 at tidal height of 148 cm in 2010, we selected images with same tidal heights. The Puldeung area was 1.37 and 1.23 km2 at the tidal height of 137 and 148 cm, respectively. The erosion at DMPA is very severe and thus it is imperative to initiate the morphodynamical study on the seasonal variation and long-term evolution of Puldeung as well as the causes and measures of Puldeung erosion.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.33 no.5
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• pp.343-351
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• 2015

It is well-known that even the DGNSS (Differential Global Navigation Satellite System) technique in navigation for ground vehicles can only provide several meters of accuracy, such that it is suitable for simple guidance. On the other hand, centimeter to millimeter level accuracy can be obtained by using carrier phase observables in the field of precision geodesy/surveying. In this study, a preliminary study was conducted to apply NRTK (Network-RTK) by NGII (National Geographic Information Institute) to ground vehicle navigation. Onboard GNSS receivers were used for NRTK throughout the country, and the applicability of NRTK on navigation was analyzed based on NRTK surveying results. The analysis shows that the overall ambiguity fixing rate of NRTK is high and is therefore possible to apply it for navigation. In urban areas, however, the fixing rate decreases sharply, therefore, it needs to employ a method to minimize the effect of the float solutions, which can reach up to 10 meters. It is still feasible to obtain a centimeter level of accuracy in some area using NRTK under certain conditions. But, the ambiguity fixing rate of FKP falls down to 55% for high speed vehicles, and so the surveying accuracy should be determined by considering various factors of surveying environments. In addition, it is difficult to fix ambiguities using single-frequency GPS receivers. Finally, several suspicious NRTK(FKP) connection problems occurred during atmospheric disturbances (phase two or up), which should be investigated further in upcoming research.

• Journal of IKEEE
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• v.5 no.2 s.9
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• pp.136-145
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• 2001

As with appearing new applications that requires QoS guarantee such as VoIP, VPN in Internet, problems of IP QoS has been one of most important issues in next-generation Internet. IETF has proposed integrated services model(Int-Serv) and differentiated service(Diff-Serv) to supply IP QoS in Internet. Int-Serv model uses the state information of each IP flow, so satisfies QoS according to traffic characteristics, but increases the amount of flow state information with increasing flow number. Diff-Serv model uses PHP(Per Hop Behavior), and there are well-defined classes to provide differentiated traffics with different services according to delay and loss sensitivity. Diff-Serv model can provide diverse services in Internet because of having no the state and signal information of each flow. As MPLS uses the packet forwarding technique based-on label, it implements the traffic engineering in the networks easily. The MPLS can set up the path with different traffic parameters, and assign each path to particular Class of Services. Therefore it is possible to support the Diff-Serv model with well-defined classes. In this paper we investigate the performance improvement of Diff-Serv function in the MPLS network to guarantee class of services in Internet.