• Ecology and Resilient Infrastructure
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• v.10 no.4
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• pp.217-225
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• 2023

This study analyzed the effect of flood level reduction in the case of creating and operating offline storage for the Jangdong district, which can be used as a flood buffer space for the Geumgang River, through one-dimensional unsteady flow numerical simulation. In particular, the sensitivity analysis of changes in the height and width (length) of transverse weirs on flood level changes was performed to provide quantitative information necessary for flood control facility (embankment) design. As a result of analyzing the flood control effect of the offline storage based on the peak flood discharge and level, spatially, the flood control effect at the planned flood buffer space site and the downstream end was confirmed, and it was confirmed that the flood reduction effect at the downstream occurred the most. By design conditions of the transverse overflow weir, the greatest flood reduction effect was found under the condition that the overflow weir height based on the 50-year frequency flood level and the transverse overflow weir width (length) of 125 m were considered. The effect of delaying the time to reach the maximum flood due to the operation of the offline storage site was also presented based on unsteady flow modeling.

• Journal of Korea Water Resources Association
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• v.44 no.12
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• pp.967-974
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• 2011

Based on daily time series from RDAPS numerical weather forecast, Streamflow prediction was simulated and the result of ESP analysis was implemented considering quantitative mid- and long-term forecast to compare the results and review applicability. The result of ESP, ESP considering quantitative weather forecast, and flow forecast from RDAPS numerical weather forecast were compared and analyzed with average observed streamflow in Guem River Basin. Through this process, the improvement effect per method was estimated. The result of ESP considering weather information was satisfactory relatively based on long-term flow forecast simulation result. Discrepancy ratio analysis for estimating accuracy of probability forecast had similar result. It is expected to simulate more accurate flow forecast for RDAPS numerical weather forecast with improved daily scenario including time resolution, which is able to accumulate 3 hours rainfall or continuous simulation estimation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.3
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• pp.139-154
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• 1993

The major purpose of this study is to develop a regionalized regression model, which predicts flood peaks from the characteristics of the ungaged catchments, through the regional flood frequency analysis for the selected stage gauging stations located on several natural rivers of Korea. The magnitude and the frequency of flood peaks with specified recurrence intervals were estimated from the flood frequency analysis on the 28 selected stage gauging stations distributed on the five major rivers of Korea. The results of the analysis were compared with the predictions from the two different flood frequency models. From the statistical evaluation of these models, it was revealed that the POT model (Peaks Over a Threshold model), which is based on the partial duration method, is more effective in predicting flood peaks from short period records than the ANNMAX model (ANNual MAXimum model) which is based on the annual maximum series method. A regionalized regression model was developed to facilitate the estimation of design floods for ungaged catchments through the regression analysis between flood peaks and the topographic characteristics of the catchments assumed to be important in runoff processes. In addition to this, the correlation diagrams are presented which show the relationships between flood peaks with specified recurrence intervals and the major characteristics of the catchments.

• Structural Engineering and Mechanics
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• v.29 no.2
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• pp.135-154
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• 2008

The moving vehicle loads on a bridge deck is one of the most important live loads of bridges. They should be understood, monitored and controlled before the bridge design as well as when the bridge is open for traffic. A MOM-based algorithm (MOMA) is proposed for identifying the timevarying moving vehicle loads from the responses of bridge deck in this paper. It aims at an acceptable solution to the ill-conditioning problem that often exists in the inverse problem of moving force identification. The moving vehicle loads are described as a combination of whole basis functions, such as orthogonal Legendre polynomials or Fourier series, and further estimated by solving the new system equations developed with the basis functions. A number of responses have been combined, some numerical simulations on single axle, two axle and multiple-axle loads, being either constant or timevarying, have been carried out and compared with the existing time domain method (TDM) in this paper. The illustrated results show that the MOMA has higher identification accuracy and robust noise immunity as well as producing an acceptable solution to ill-conditioning cases to some extent when it is used to identify the moving force from bridge responses.

• Smart Structures and Systems
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• v.20 no.6
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• pp.769-780
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• 2017

Cable force monitoring is an essential and critical part of the safety evaluation of cable-supported bridges. A reasonable cable force monitoring scheme, particularly, sensor placement related to accurate safety assessment and budget cost-saving becomes a major concern of bridge administrative authorities. This paper presents optimal sensor placement for cable force monitoring by selecting representative sensor positions, which consider the spatial correlativeness existing in the cable group. The limited sensors would be utilized for maximizing useful information from the monitored bridges. The maximum information coefficient (MIC), mutual information (MI) based kernel density estimation, as well as Pearson coefficients, were all employed to detect potential spatial correlation in the cable group. Compared with the Pearson coefficient and MIC, the mutual information is more suitable for identifying the association existing in cable group and thus, is selected to describe the spatial relevance in this study. Then, the bond energy algorithm, which collects clusters based on the relationship of surrounding elements, is used for the optimal placement of cable sensors. Several optimal placement strategies are discussed with different correlation thresholds for the cable group of Nanjing No.3 Yangtze River Bridge, verifying the effectiveness of the proposed method.

• Journal of Koreanology Reviews
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• v.1 no.1
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• pp.37-49
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• 2022

The purpose of this study is to discuss how Dongi People in ancient societies resided in the region including the Korean Peninsula shaped its economy, what kind of currency was used, and their economic activities using this currency. This study started from a skeptical point of view that the Dongi People were conducting economic activities with the currency used in the country made by the Jina People before and after the Gojoseon society. Currently, in China, all currencies issued in China are treated as their own currency. It is due to subjective interpretation from a nationalist point of view. Japan subjectively interprets and judges from a Japanese point of view and North Korea judges from the central point of view on the Korean Peninsula. This difference is due to the subjective interpretation from the researcher which has been affected by their associating academic area. This has caused the lack of objectivity. In other words, it means that there is a big difference in the perception of the interpretation of history between different academic areas. This study, therefore, tried to avoid the application of biased concept or academic research in order to define the distribution economics more objectively by conducting the study based on the literature sources from Chinese ancient books and field research materials as much as possible, as the study and research conducted based on the domestic sources are insufficient in the sense that there is a gap between different perceptions and interpretations. As a conclusion of this study, the excavation area of Myeong-do-jeon is perfectly consistent with the old river area of Gojoseon, and in particular, considering Gojoseon was in the hostile relationship with Yan, it was found that only Myeong-do-jeon was used without using any other Chinese currency in the entire Gojoseon area, not just some areas. It is also a decisive clue to prove that it is not the Yan currency. The limitation of this study in developing the discussion different from the current research and study is that there was a lack of exploration and investigation of various documents and relics. For future research, this study will become more meaningful when it is conducted simultaneously with the discovering of new documents as well as the relics.

• Geomechanics and Engineering
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• v.30 no.5
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• pp.401-411
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• 2022

To obtain the dynamic mechanical properties, fracture modes, energy and brittleness characteristics of Furong Baijiao coal rock, the dynamic impact compression tests under 0, 4, 8 and 12 MPa confining pressure were carried out using the split Hopkinson pressure bar. The results show that failure mode of coal rock in uniaxial state is axial splitting failure, while it is mainly compression-shear failure with tensile failure in triaxial state. With strain rate and confining pressure increasing, compressive strength and peak strain increase, average fragmentation increases and fractal dimension decreases. Based on energy dissipation theory, the dissipated energy density of coal rock increases gradually with growing confining pressure, but it has little correlation with strain rate. Considering progressive destruction process of coal rock, damage variable was defined as the ratio of dissipated energy density to total absorbed energy density. The maximum damage rate was obtained by deriving damage variable to reflect its maximum failure severity, then a brittleness index BD was established based on the maximum damage rate. BD value declined gradually as confining pressure and strain rate increase, indicating the decrease of brittleness and destruction degree. When confining pressure rises to 12 MPa, brittleness index and average fragmentation gradually stabilize, which shows confining pressure growing cannot cause continuous damage. Finally, integrating dynamic deformation and destruction process of coal rock and according to its final failure characteristics under different confining pressures, BD value is used to classify the brittleness into four grades.

• Journal of Digital Convergence
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• v.16 no.4
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• pp.299-306
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• 2018

This study is to measure traveling experience of bike riders whom going long distance trip. Bike paths and bike riding are crucial element for modern people's life style. At the same time, a bicycle trail is being developed by the National Bicycled-Oriented Chair Plan, which was established in 2009 by the National Bike Policy Master Plan. 13 million bike riders in Korea is keep on trying the long distance bike trip and its number is increasing every year. Accordingly, the Ministry of Public Administration and Security decides to promote the convenience of riders by developing bicycle app for long distance rider. The study attempted to assess usability of this app with 39 bike applications whom currently using the bike application. Afterwards, the researchers tests 11 hypotheses through in-depth interviews of six activated members. In sum, Bicycle travelers should be provided with bike trail guidance based on theme section skill, provided in-time speed distance related information, communicated with other bike riders, given tips for bike supplies and maintenance, and provided English language service. The study hopes to help find a customized service for bike travelers.

• Korean Institute of Interior Design Journal
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• v.19 no.6
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• pp.206-213
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• 2010

This study, for church architectural amenities for the aged, with a base of 'laws on securing promotion of convenience for the disabled, aged, and pregnant women,' would like to propose improvement program after figuring out church worker (priest)'s willingness for amenities improvement, request of the aged church members, and level of request by different ages of the aged church members and total number of church members. The scope of geographical range for the study is limited to Northern side of Han River in Seoul and the churches with its own building having 500 to 3,000 people attending services, and implementation range, with a base of laws on promotion of convenience, separates specific items into mediation facility, interior facility, sanitary facility, and other facilities. The study selected 40 workers in church and 339 aged church members as subjects. As analysis method for the study, we have measured reliance level of questions by performing reliance test on each question, and performed frequency analysis in order to observe church worker's willingness to improve and request level of the aged church members. And, in order to find out the difference on opinion by the aged church members and total number of church members, we have performed "One way ANOVA," that verifies average difference. For evidence analysis we have verified all of them in attention level of p<.05, and for statistics analysis we have analyzed them using SPSSWIN 12.0 program. We are proposing improvement program based on study and analysis as next: First, since most of church workers have strong willingness to improve amenities we have learned that it is very optimistic to see improvements on church's amenities in the future. Second, since the aged church members' level of request was high on 3 of mediation facilities, elevators, and restrooms, it is desirable to improve mainly with these facilities. Third, the result on level of request for facilities based on the total number of church members revealed that the churches with 1,000-2,000 members have the highest level of request. Thus, we feel that the churches with 1,000-2,000 members should try harder to improve compared with churches with different number of members. Fourth, since the level of request on church amenities by different age group showed that the age group with 65-70 had the highest level of request on all facilities, except elevators, there are needs to apply the opinions of this age group more in depth based on this result.

• Journal of Wetlands Research
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• v.24 no.3
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• pp.170-184
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• 2022

The Riparian Buffer Zone(RBZ) is a sustainable social-ecological system created in the middle zone between water and land. For the RBZ, close communication with the local community is important, and it is necessary to promote it as a communicative environmental planning process. In this study, for the RBZ project, three strategies are presented as a communicative act to understand and implement planning. First, government-led projects were avoided and improved to a process in which citizens and stakeholders participated together, centered on local partnership. Second, it was intended to introduce design criterias in terms of enhancing the function of ecosystem services that citizens can sympathize with, and to increase acceptance and awareness through the planning of preferred spaces and facilities. Third, after a balanced plan for habitats, water cycle-based ecological environment, ecological experience and open space, citizens felt the restoration effect and value as an ecological resources, and a system was prepared to participate in the operation and management. This study will work as a process model based on citizens's participation. In addition, it will be possible to provide lessons for the change of the policy paradigm for the RBZ and the implementation of similar projects in the future.