• Atmosphere
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• v.28 no.4
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• pp.479-490
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• 2018

This study assesses the prediction skill of regional scale model for the mean temperature anomaly over South Korea produced by Pusan National University Coupled General Circulation Model (PNU CGCM)-Weather Research and Forecasting (WRF) chain. The initial and boundary conditions of WRF are derived from PNU CGCM. The hindcast period is 11 years from 2007 to 2017. The model's prediction skill of mean temperature anomaly is evaluated in terms of the temporal correlation coefficient (TCC), root mean square error (RMSE) and skill scores which are Heidke skill score (HSS), hit rate (HR), false alarm rate (FAR). The predictions of WRF and PNU CGCM are overall similar to observation (OBS). However, TCC of WRF with OBS is higher than that of PNU CGCM and the variation of mean temperature is more comparable to OBS than that of PNU CGCM. The prediction skill of WRF is higher in March and April but lower in October to December. HSS is as high as above 0.25 and HR (FAR) is as high (low) as above (below) 0.35 in 2-month lead time. According to the spatial distribution of HSS, predictability is not concentrated in a specific region but homogeneously spread throughout the whole region of South Korea.

• The Journal of the Korea Contents Association
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• v.19 no.4
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• pp.30-40
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• 2019

As the urban scale changes and the construction technology develops, the living space is being expanded in three dimensions. However, despite the development of construction technology represented by the appearance of skyscrapers, damage to high - rise buildings with dense population can be rather high. In order to solve such a situation, digital twin technology that can control and predict the real world in real time can be an alternative, and it is necessary to utilize pre-constructed spatial information actively. Therefore, this study aims to provide a standardized data model for using existing such information as well as various information produced in the future to the building disaster prevention field. To this end, we developed a data model that extends the CityGML standard, a representative city information model, to disaster prevention.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.5
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• pp.57-68
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• 2019

Rural tourism has been identified as providing opportunities to revitalize the rural economies since early 2000s. During last decade in South Korea, government has enacted many policies aiming to establish tourism support programs as well as instigating activities between rural and nearby urban districts. In particular, the promotion of the rural tourism has been actively sought in various forms of products and services, such as green tourism village, village festival, one-company one-village campaign and etc. However, in order to prepare effective policies, it is very crucial to identify measureable evaluation criteria that can be used to assess socio-economic situations of the rural districts. Such criteria should be objective, timely and provide insights about living conditions of local residents and relevant properties. They can also be used to evaluate if progress is being made after the policies are implemented. While considerable efforts and resources have been invested to aid the tourism programs in South Korea, we still lack such systematic means to quantify and evaluate its impact on rural districts. In this work, we have applied regional deprivation analysis on well-established community experiential and recreational business in rural villages throughout the country based on three criteria (i.e., population, local commerce, and buildings). Surprisingly, the result shows that the implementation of the community experiential and recreational businesses did not bring any noticeable changes to at least one of the evaluation criteria. We concluded that the current government policies on revitalization of rural tourism at the village scale is insufficient for bringing meaningful socio-economic impacts to rural districts, with rare exceptions.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.181-181
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• 2018

설계홍수량 산정 시 지점확률강우량을 대상유역 내 면적강우량으로 환산하기 위하여 면적우량 환산계수(areal reduction factor, ARF)를 적용한다. ARF 산정방법은 크게 면적고정형 방법과 호우중심형 방법으로 나뉜다. 면적고정형 방법은 현재 국내 하천설계기준에서 설계강우량 산정 시 활용하고 있는 방법이지만, 동 시간에 발생한 강우사상을 활용하지 않고 지점강우량과 면적강우량의 독립적인 빈도해석을 통해 산정되므로 비현실적인 값이라고 볼 수 있다. 본 연구에서는 강우사상의 공간분포 특성을 효과적으로 반영할 수 있는 레이더 강우 자료를 활용하여 한강권역의 호우중심형 ARF를 활용하였다. 호우중심형 ARF는 지속기간 1, 3, 6, 12, 24시간에 대하여 산정하였으며, 재현기간은 강우 사상의 규모에 따라 총 다섯 구간(0-10, 10-20, 20-50, 50-80, 80-100년)으로 분류하였다. 지속기간 및 재현기간에 따른 호우중심형 ARF는 강우 사상마다 산정되므로 다양한 값이 산재(scattered)되어 있는데, 대푯값을 선정하기 위하여 Weibull 분포의 비초과확률 95%의 값을 추출하였다. 두 가지 방법으로 산정된 ARF는 지속기간에 대하여 로그형태로 증가하였으나, 재현기간에 따른 관계에서는 차이를 보였다. 면적고정형 ARF는 재현기간에 대한 민감도가 매우 낮았으나, 호우중심형 ARF는 재현기간에 따라 감소하였다. 또한 호우중심형 ARF는 지속시간이 길수록 재현기간에 대한 민감도가 점차 낮아졌으며 지속기간 24시간 이후로는 일정한 값을 보였다. 이러한 차이는 레이더 실 강우를 활용한 호우중심형 ARF 산정 시에 면적고정형 ARF 산정과정에서 고려되지 않는 강우의 시 공간적 특성을 반영하기 때문인 것으로 사료된다. 따라서 설계홍수량 산정 시 호우중심형 ARF를 적용한다면 보다 현실적인 값을 제시할 수 있을 것으로 판단된다.

• Investigative Magnetic Resonance Imaging
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• v.25 no.2
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• pp.118-128
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• 2021

Purpose: To investigate the value of MR textural analysis, including use of diffusion-weighted imaging (DWI) to differentiate malignant from benign soft-tissue tumors on 3T MRI. Materials and Methods: We enrolled 69 patients (25 men, 44 women, ages 18 to 84 years) with pathologically confirmed soft-tissue tumors (29 benign, 40 malignant) who underwent pre-treatment 3T-MRI. We calculated MR texture, including mean, standard deviation (SD), skewness, kurtosis, mean of positive pixels (MPP), and entropy, according to different spatial-scale factors (SSF, 0, 2, 4, 6) on axial T1- and T2-weighted images (T1WI, T2WI), contrast-enhanced T1WI (CE-T1WI), high b-value DWI (800 sec/mm²), and apparent diffusion coefficient (ADC) map. We used the Mann-Whitney U test, logistic regression, and area under the receiver operating characteristic curve (AUC) for statistical analysis. Results: Malignant soft-tissue tumors had significantly lower mean values of DWI, ADC, T2WI and CE-T1WI, MPP of ADC, and CE-T1WI, but significantly higher kurtosis of DWI, T1WI, and CE-T1WI, and entropy of DWI, ADC, and T2WI than did benign tumors (P < 0.050). In multivariate logistic regression, the mean ADC value (SSF, 6) and kurtosis of CE-T1WI (SSF, 4) were independently associated with malignancy (P ≤ 0.009). A multivariate model of MR features worked well for diagnosis of malignant soft-tissue tumors (AUC, 0.909). Conclusion: Accurate diagnosis could be obtained using MR textural analysis with DWI and CE-T1WI in differentiating benign from malignant soft-tissue tumors.

• Journal of Digital Convergence
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• v.19 no.7
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• pp.319-325
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• 2021

The urban regeneration project is an activity that promotes the economy in underdeveloped commercial or residential areas and maintains urban communities through improvement of living in residential areas. Through this study, various successful cases of urban regeneration at home and abroad and surveys related to urban regeneration in Bongsan Village, Yeongdo, Busan were collected and analyzed. Key keywords for each case were derived, grouped, and top keywords were created. The 13 top keywords were evaluated using Likert's 5-point scale, and AHP was conducted for the 10 keywords that were finally selected. As a result of AHP analysis, the preference for "spatial and physical properties" was derived in the order of "publicity", "sustainability", and "identity". The preference of "content and system properties" was derived in the order of "resident participation", "convenience", "locality", and "local government participation". It is necessary to present a role as a design guideline for establishing urban regeneration designs in relation to various urban regeneration projects that will become more active in the future through the analysis of preferences of urban regeneration keywords derived through this study.

• Journal of Ocean Engineering and Technology
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• v.35 no.6
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• pp.446-456
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• 2021

To build an environment facility of a large-scale ocean basin, various detailed reviews are required, but it is difficult to find data that introduces the related research or construction processes on the environment facility. The current generator facility for offshore structure safety evaluation tests should be implemented by rotating the water of the basin. However, when the water in the large basin rotates, relatively large flow irregularities may occur and the uniformity may not be adequate. In this paper, design and review were conducted to satisfy the performance goals of the DOEB through computational numerical analysis on the shape of the waterway and the flow straightening devices to form the current in the large tank. Based on this, the head loss, which decreases the flow rate when the large tank water rotates through the water channel, was estimated and used as the pump capacity (impeller) design data. The impeller of the DOEB current generator was designed through computational numerical analysis (CFD) based on the lift surface theory from the axial-type impeller shape for satisfying the head loss of the waterway and maximum current velocity. In order to confirm the performance of the designed impeller system, the flow rate and flow velocity performance were checked through factory test operation. And, after installing DOEB, the current flow rate and velocity performance were reviewed compare with the original design target values. Finally, by measuring the current velocity of the test area in DOEB formed through the current generator, the spatial current distribution characteristics in the test area were analyzed. Through the analysis of the current distribution characteristics of the DOEB test area, it was confirmed that the realization of the maximum current velocity and the average flow velocity distribution, the main performance goals in the waterway design process, were satisfied.

• Journal of the Korean Association of Geographic Information Studies
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• v.25 no.2
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• pp.100-109
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• 2022

Large-scale urban concentration of population and vehicles due to economic growth in Korea has been causing serious urban transport problems. Although the collection of congestion pricing has been evaluated as the most effective transportation policy to alleviate traffic demand, its effectiveness is very limited as it was just executed around congested points or along main arterial roads. This study derived dynamic congestion zones with the average travel speed of 206 traffic analysis zones in Busan Metropolitan City to propose a dynamic congestion pricing collection system by employing Space-Time Cube Analysis and Emerging Hot Spot Analysis. As a result, dynamic hot spots were formed from 7h to 24h and particularly, traffic congestion was severely deteriorated from 18h to 20h around Seomyeon and Gwangbok-dong. Therefore, it is expected that the effect of dynamic congestion pricing will be maximized in managing traffic demand in the city center.

• Composites Research
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• v.35 no.3
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• pp.188-195
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• 2022

This paper proposes a multiscale process-structural analysis methodology and applies to a battery housing part made of the short fiber-reinforced and fabric-reinforced composite layers. In particular, uncertainties of the material properties within the microscale representative volume element (RVE) were considered. The random spatial distribution of matrix properties in the microscale RVE was realized by the Karhunen-Loeve Expansion (KLE) method. Then, effective properties of the RVE reflecting on spatially varying matrix properties were obtained by the computational homogenization and mapped to a macroscale FE (finite element) model. Morever, through the hybrid process simulation, a FE (finite element) model mapping residual stress and fiber orientation from compression molding simulation is combined with one mapping fiber orientation from the draping process simulation. The proposed method is expected to rigorously evaluate the design requirements of the battery housing part and composite materials having various material configurations.

• Journal of the Korean Geosynthetics Society
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• v.20 no.4
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• pp.113-124
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• 2021

Underground environmental infrastructure and energy production facilities, which are recognized as avoidable facilities such as landfills, are emerging as an important social issue due to urbanization and economic growth. In order to safely construct a large-scale plant facility in the underground space, it is necessary to increase the utilization of the limited space layout and minimize unnecessary columns. In this study, the plant modularization method(Pipe Rack Module) was reviewed to solve the problems of work constraints, assembly and demolition, process system interconnection, and maintenance that occur when plant facilities are underground. In addition, plant module analysis was performed by applying various load conditions (earthquake load, device load, earth pressure load, etc.) to improve spatial layout usability and secure structure stability. Based on the analysis results under various boundary condition, the implications regarding the minimum installation interval and module arrangement (draft) of basic modules required for the construction of an underground combined plant were derived.