• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.4
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• pp.201-212
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• 2016

A Wind resource assessment and optimal micrositing of wind turbines were implemented for the development of an onshore wind farm of 30 MW capacity on Gadeok Island in Busan, Republic of Korea. The wind data measured by the automatic weather system (AWS) that was installed and operated in the candidate area were used, and a reliability investigation was conducted through a data quality check. The AWS data were measured for one year, and were corrected for the long term of 30 years by using the modern era retrospective analysis for research and application (MERRA) reanalysis data and a measure- correlate-predict (MCP) technique; the corrected data were used for the optimal micrositing of the wind turbines. The micrositing of the 3 MW wind turbines was conducted under 25 conditions, then the best-optimized layout was analyzed with a various wake model. When the optimization was complete, the estimated park efficiency and capacity factor were from 97.6 to 98.7 and from 37.9 to 38.3, respectively. Furthermore, the annual energy production (AEP), including wake losses, was estimated to be from 99,598.4 MWh to 100,732.9 MWh, and the area was confirmed as a highly economical location for development of a wind farm.

• Journal of Korea Spatial Information System Society
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• v.7 no.3 s.15
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• pp.93-106
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• 2005

Recently, the web map services with standard interfaces have been developed to a high degree for the purpose of sharing of spatial data through the web. Among the various kinds of works related, the specification for the web map service released by Open Geospatial Consortium (OGC) is the most prominent, and is nearly adopted as international standard (ISO/DIS 19128) in developing the web map servers. The web map server of OGC, however, provides the insufficient capabilities for mobile applications. Unlike the wired applications, the mobile applications would require the map server to minimize of size of data transferred, because the size of data is very important factor in communication cost and the response time of map clients. And the mobile applications require different quality of map according to the screen size of mobile devices. The mobile application, also require some application specific queries. In this paper, We have Proposed the interfaces for mobile web map services (M-WMS) which fully comply with the standard interfaces proposed in OGC. And we have designed and implemented the web map server for mobile map services. This paper has contributed to construction and practical use of the web map servers in mobile applications, such as LBS and telematics.

• The Journal of Engineering Geology
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• v.26 no.2
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• pp.251-260
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• 2016

Groundwater flow due to hydraulic gradients across a geologic barrier surrounding a dam reservoir can cause swamps or wetlands to form on the downstream side of the dam, thereby restricting land use. The difference in head between the reservoir level and the downstream groundwater level creates a hydraulic gradient, allowing water to flow through the geologic barrier. We constructed a drainage system at the Daecheong dam to study the effects on groundwater levels and soil moisture contents. The drainage system consisted of a buried screened pipe spanning a depth of 1-1.5 m below a land surface. Groundwater levels were monitored at several monitoring wells before and after the drainage system was installed. Most well sites recorded a decline in groundwater level on the order of 1 m. The high-elevated site (monitoring well W1) close to the reservoir showed a significant decline in groundwater level of more than 2 m, likely due to rapid discharge by the drainage system. Soil moisture contents were also analyzed and found to have decreased after the installation of the drainage system, even considering standard deviations in the soil moisture contents. We conclude that the drainage system effectively lowered groundwater levels on the downstream side of the dam. Furthermore, we emphasize that water seepage analyses are critical to embankment dam design and construction, especially in areas where downstream land use is of interest.

• Journal of Digital Convergence
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• v.13 no.7
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• pp.1-8
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• 2015

To identify the satisfaction level towards Gwangju regional TV broadcasting company's program, "I Like the Market" and the effect of market vitalization on the market merchants' public relationships, this study carried out survey targeting 256 merchants who are residing at the region. The research results demonstrated that the satisfaction level towards the program and market vitalization via the program exert significant effect on the public relationships. Specifically, satisfaction level towards the program for the vitalization of regional broadcast exert effect in the following order; devotion, relationship and reliability. Meanwhile, market vitalization exert positive effect on the relationship, reliability and devotion, in the order mentioned. This implies that the development of quality program for the regional residents plays an important role in the convergence of regional broadcast and in increasing broadcasting company's brand image. Accordingly, positive interaction via regional vitalization when it comes to the formation of regional broadcast program going forth may be needed for regional broadcast policies.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.2
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• pp.168-176
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• 2017

HNS accidents involve large-scale fires and explosions, causing numerous human casualties and extreme environmental pollution in the surrounding area. The widespread diffusion of effects should be prevented through rapid decision making. In this study, a high-quality, standardized, and digitized HNS accident databases has been generated based on the HNS standard code proposed. Furthermore, the HNS Accident Tracking System (HATS) was applied and implemented to allow for systematic integration management and sharing. In addition, statistical analysis was performed on 76 cases of domestic HNS accident data collected over 23 years using HATS. In Korea, an average of 3.3 HNS accidents occurred each year and major HNS accident factors were Springs (41 %), Aprons (51 %), Chemical Carriers (49 %), Crew's Fault (45 %) and Xylenes (12 %). (The number in parentheses is the percentage of HNS accident factors for each HNS accident classification)

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.1
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• pp.140-145
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• 2010

In this work, to theoretically analyze the nonlinear charging characteristic, a Radial Basis Function Neural Network (RBFNN) is adopted. Based on the RBFNN, an charging characteristic tendency of a Linear Type Magnetic Flux Pump (LTMFP) is analyzed. In the paper, we developed the LTMFP that generates stable and controllable charging current and also experimentally investigated its charging characteristic in the cryogenic system. From these experimental results, the charging current of the LTMFP was also found to be frequency dependent with nonlinear quality due to the nonlinear magnetic behaviour of superconducting Nb foil. On the whole, in the case of essentially cryogenic experiment, since cooling costs loomed large in the cryogenic environment, it is difficult to carry out various experiments. Consequentially, in this paper, we estimated the nonlinear characteristic of charging current as well as realized the intelligent model via the design of RBFNN based on the experimental data. In this paper, we view RBF neural networks as predominantly data driven constructs whose processing is based upon an effective usage of experimental data through a prudent process of Fuzzy C-Means clustering method. Also, the receptive fields of the proposed RBF neural network are formed by the FCM clustering.

• Applied Biological Chemistry
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• v.49 no.3
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• pp.215-220
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• 2006

Response surface methodology was implemented to determine an optimal extraction condition in Phellinus linteus water extract. Extraction was performed on 10 experimental conditions including independent variables such as extraction time $(1{\sim}5\;hrs)$ and water volume over sample (sample : $H_2O$ = 1 : $40{\sim}200$, W/V), color browning, reducing and total sugar, that were based on the significant levels of 10% of central composition design. Color browning, reducing and total sugar contents were found to be more affected when the water volume was increased rather than extraction time. Maximum extraction condition was acquired at extraction time of $3.0{\sim}4.5\;hrs$ and water volume of $40{\sim}58.2\;ml$. Being extracted at the optimal extraction condition two of the free sugars, sucrose (0.126%) and glucose (0.012%), were detected. Total content of the free amino acids was found to be $503.26\;{\mu}g%$. Among them, essential amino acid contents were revealed as 5.4%. One major peak from gel permeation chromatography contained polysaccharide(s) with the molecular weights of 10 KDa.

• Journal of Korean Society of Transportation
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• v.20 no.7
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• pp.107-116
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• 2002

Crash Cushion is a kind of safety facilities on roadside which acts the role of absorbing impact energy when vehicles are driven out of normal route such as Gore area of freeway off ramp. Criteria for severity index considering accident occurrence possibility are needed to have strong effect on installing the facilities. However, present criteria for establishing crash cushion design do not include such processes. Therefore, the paper presents two kinds of study to develop criteria for severity index. First of all, development of accident forecasting model on freeway off ramp is presented. The module is a relationship between accidents and road environment by negative binomial distribution (NB) which is called to reflect very well quality of accidents at Gore of crash cushion installed freeway Secondly, freeway exiting behavior model is developed because the human factor is the most important one. However, many literatures have shown between road environment and accidents which are more quantitative than human factor. The study supposed advanced process steps on actual freeway and analysed correlation between variables and accidents. The criteria for severity index is presented to determine whether to install or not by benefit cost analysis for each module. The standard for severity index will help to determine whether to install the crash cushion or not and to estimate severity for freeway and off ramp.

• Korean Journal of Comparative Education
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• v.23 no.5
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• pp.53-75
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• 2013

This article explores the impact of mergers on the experiences of students. A case design is used to gain an in-depth understanding of the students in a Korean university that was combined with a two-year college in 2007. Semi-structured interviews of 11 direct entrants, 5 transfer students, and 7 professors were conducted in 2010 for the data collection. The results suggest that mergers do not necessarily ensure the integration of the students involved. Since mergers pose enormous challenges to both transfer students and direct entrants, university leaders need to give careful attention to students' persistence and integration as the campus changes. The results also reveal that students' experience of mergers may be affected by cultural backgrounds as well as the hierarchical structure of higher education. In Korean society, where credentialism prevails, mergers can have different impacts on students who come from initial institutions of differing perceived quality, and thus mergers may incite tension among the students. In light of these concerns, this study's findings highlight the importance of student integration as a key element in mergers.

• Journal of Convergence for Information Technology
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• v.11 no.12
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• pp.138-147
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• 2021

This study aims to analyze the characteristics and preferences of learners who participated in college online classes for effective online learning. A total of 101 college students who participated in online classes completed the survey including personal characteristics of students and learning factors that affect online classes. The results showed that male students were more likely than female students to respond that online classes were more effective. Likewise students who learned from video recordings compared to those who learned from real-time lectures. As a result of analyzing the difficulties of online learning, there was a high probability that online learning was ineffective for students who had difficulties in self-learning and asking questions to their lecturers. Likewise, students who spent a lot of time studying online lectures, there was a high probability that online classes would be more effective for students who spent a lot of time on assignments. The results suggest that online learning is more effective for students who learn actively and self-directedly than those who passively participate in classes. This study implies that it is necessary to design online classes based on the characteristics and preferences of learners to improve the quality of education.