• 대기
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• 제21권1호
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• pp.95-108
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• 2011

The effects of an apartment complex on flow and pollutant dispersion in an urban area are numerically investigated using a computational fluid dynamics (CFD) model. The CFD model is based on the Reynolds-averaged Navier-Stokes equations and includes the renormalization group k-${\varepsilon}$ turbulence model. The geographic information system (GIS) data is used as an input data of the CFD model. Eight numerical simulations are carried out for different inflow directions and, for each inflow direction, the effects of an apartment complex are investigated, comparing the characteristics of flow and dispersion before and after construction of the apartment complex in detail. The observation data of automatic weather system (AWS) is analyzed. The windrose analysis shows that the wind speed and direction after the construction of the complex are quite different from those before the construction. The construction of the apartment complex resulted in the decrease in wind speed at the downwind region. It is also shown that the wind speed increased partially inside the apartment complex due to the channeling effect to satisfy the mass continuity. On the whole, the wind speed decreased at the downwind region due to the drag effect by the apartment complex. As a result, the passive pollutant concentration increased (decreased) near the downwind region of (within) the apartment complex compared with that before the construction.

• 한국게임학회 논문지
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• 제17권6호
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• pp.139-152
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• 2017

본 논문에서는 구면 영상에서 영역 분할 정보를 사용하여 바닥 영역을 검출하는 방법을 제시한다. 평면 영상에서의 Watershed 영역 분할 방법을 수정하여 구면 영상의 영역 분할에 적용할 수 있도록 하였다. 영역들을 분할한 뒤 가정된 바닥 영역 픽셀의 색상과 질감을 그 외의 영역들과 비교하여 바닥 영역을 검출한다. 구면 파노라마 영상에서는 구면 왜곡으로 인하여 평면에서의 바닥 검출 방법을 그대로 적용할 수 없다. 구면 왜곡을 고려한 바닥 영역 검출을 위하여 바닥 영역의 외곽선을 검출하는 알고리즘을 설계하였다. 실험에서 지상물이 없는 경우와 있는 경우의 모두에서 적절하게 바닥 영역을 검출할 수 있는 결과를 보였다.

• 한국항공운항학회지
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• 제14권3호
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• pp.7-15
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• 2006

Aerodynamic analysis of an airfoil in the transonic region was automated in order to enable parametric study by using the journal file of the commercial analysis code FLUENT, pre/post process Gambit and computational mathematics code MATLAB. The automated capability was illustrated via NACA 0012 and RAE 2822 airfoils. This analysis was carried out at Mach numbers ranged from 0.70 to 0.80, angles of attack; 1$^{\circ}$, 2$^{\circ}$ and 4$^{\circ}$, Reynolds numbers; 4.0${\times}$106, 6.5${\times}$106. The analysis results of a pressure coefficient were verified by comparing with the experimental data which were measured in terms of chord length because the pressure coefficient of an airfoil surface is a good estimator of flow characteristics. The results of two airfoils show that this analysis code is useful enough to be used in the design optimization of airfoil.

• 조명전기설비학회논문지
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• 제28권1호
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• pp.69-78
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• 2014

In this paper, characteristics of wireless power transfer (WPT) systems using magnetically coupled resonance scheme with relay coils are investigated and modeled. Especially, asymmetric frequency splitting characteristics in over-coupled region of WPT with relays are measured and accurately modeled. Transmitter, receiver, and relay coils are modeled with R, L, C equivalent circuits. Using these circuit models and mutual inductances between coils, a WPT system is described with a linear matrix equation. For under-coupled region, a matrix is simplified considering only mutual inductances between adjacent coils. An analytical transfer characteristic of WPT system vs. distance is extracted using an inverse matrix that is acquired by Gauss elimination method for the simplified matrix. For over-coupled region, a matrix considering mutual inductances between non-adjacent coils is used to predict a frequency splitting characteristics accurately. A 6.3MHz WPT system with relay coils is implemented and measured. An accuracy of the model is investigated by comparing the output of the model with the measured results.

• Computers and Concrete
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• 제21권6호
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• pp.669-679
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• 2018

In this paper the behavior of reinforced concrete (RC) beam-column connections under cyclic loading was analyzed. The specimens, manufactured in a reduced-scale were made of (a) recycled aggregate concrete (RAC) by replacing 30% of natural coarse aggregate (NCA) with recycled coarse aggregate (RCA) and (b) RAC incorporating Polyethylene terephthalate (PET) fiber i.e., PET fiber-reinforced concrete (PFRC) at the joint region. PET fiber (aspect ratio=25) of 0.5% by weight of concrete used in the PFRC mix was obtained by hand cutting of post-consumer PET bottles. A reference specimen was also prepared using 100% of NCA and subjected to similar loading sequence. Comparing the results the structural behavior under cyclic loading of RAC specimens are quite similar to the reference specimens. Damage tolerance, load resisting capacity, stiffness degradation, ductility, and energy dissipation of the RAC specimens enhanced due to addition of PET fibers at the joint region. PFRC specimens also presented a lower damage indices and higher principal tensile stresses as compared to the RAC specimens. The results obtained gave experimental evidence on the feasibility of RAC for structural use. Using PET fibers as a discrete reinforcement is recommended for improving the seismic performance of RAC specimens.

• Earthquakes and Structures
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• 제20권1호
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• pp.97-107
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• 2021

A comprehensive study on seismic performance of wood frame building in hilly regions is presented. Specifically, seismic fragility assessment of a typical wood frame building at various locations of the northeast region of India are demonstrated. A three-dimensional simplified model of the wood frame building is developed with due consideration to nonlinear behaviour of shear walls under lateral loads. In doing so, a trilinear model having improved capability to capture the force-deformation behaviour of shear walls including the strength degradation at higher deformations is proposed. The improved capability of the proposed model to capture the force-deformation behaviour of shear wall is validated by comparing with the existing experimental results. The structural demand values are obtained from nonlinear time history analysis (NLTHA) of the three-dimensional wood frame model considering the effect of uncertainty due to record to record variation of ground motions and structural parameters as well. The ground motion bins necessary for NLTHA are prepared based on the identified hazard level from probabilistic seismic hazard analysis of the considered locations. The maximum likelihood estimates of the lognormal fragility parameters are obtained from the observed failure cases and the seismic fragilities corresponding to different locations are estimated accordingly. The results of the numerical study show that the wood frame constructions commonly found in the region are likely to suffer minor cracking or damage in the shear walls under the earthquake occurrence corresponding to the estimated seismic hazard level; however, poses negligible risk against complete collapse of such structures.

• Molecules and Cells
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• 제45권8호
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• pp.522-530
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• 2022

Transposable elements (TEs) account for approximately 45% of the human genome. TEs have proliferated randomly and integrated into functional genes during hominoid radiation. They appear as right-handed B-DNA double helices and slightly elongated left-handed Z-DNAs. Human endogenous retrovirus (HERV) families are widely distributed in human chromosomes at a ratio of 8%. They contain a 5'-long terminal repeat (LTR)-gag-pol-env-3'-LTR structure. LTRs contain the U3 enhancer and promoter region, transcribed R region, and U5 region. LTRs can influence host gene expression by acting as regulatory elements. In this review, we describe the alternative promoters derived from LTR elements that overlap Z-DNA by comparing Z-hunt and DeepZ data for human functional genes. We also present evidence showing the regulatory activity of LTR elements containing Z-DNA in GSDML. Taken together, the regulatory activity of LTR elements with Z-DNA allows us to understand gene function in relation to various human diseases.

• 한국환경과학회지
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• 제31권11호
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• pp.923-931
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• 2022

The aim of this study was to analyze differences in the perception of Gangwon-do residents using a satisfaction survey. The residents were found to be most satisfied with sectors such as parks/green spaces, landscape, and public order; however, they were least satisfied with transportation, culture, sports, medical services, and welfare facilities. Additionally, among all the items in the satisfaction survey, job satisfaction was the lowest. When comparing satisfaction trends observed in the city to those of the county, the overall satisfaction of the county was found to be slightly higher. This result could be attributed to young people being underrepresented in this survey in conjunction with the greater policy-level support for middle-aged people by from the government and Gangwon-do. Therefore, it would be worthwhile to create policies that primarily support young people and to also to create high-quality jobs with stable pay and employment prospects. This could minimize the outflow of youth and even encourage their inflow to similar small provincial cities. In Southern region and Seorak region of Gangwon-do, the satisfaction with gap between house price and region was low, which might be related to the increased demand for real estate throughout this area.

• 무역학회지
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• 제46권4호
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• pp.39-60
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• 2021

Despite the fast growth and rising importance of digital trade, there still exists no multilateral agreement governing digital trade. Significant differences in policy directions regarding key digital trade issues among the U.S., EU and China are the main stumbling blocks for reaching agreement on the multilateral front. To overcome this deficiency in digital trade rules, there has been active movement among mainly countries in the Asia-Pacific region for rule-making on digital trade. Starting with the CPTPP chapter on E-Commerce in 2018, there has been a series of digital trade rules agreed in bilateral or plurilateral formats, such as the USMCA, USJDTA, DEPA, DEA and RCEP. Korea is currently only member of RCEP, which contains an e-commerce chapter with lower levels of commitment as compared to other digital trade agreements. This paper provides a broad analysis of the recently concluded digital trade agreements, comparing the different coverage of rules, levels of commitment, and rules templates. The analysis aims to provide implications for the desirable direction of rule-making on digital trade and Korea's digital trade strategy.

• 한국환경보건학회지
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• 제42권3호
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• pp.213-223
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• 2016

Objectives: This study was designed to assess the level of physical exposure to heavy metals among residents who live around a Chungcheongnam-do Province industrial complex and to provide baseline data on the effects and harms of heavy metals on the human body by comparing their exposure levels to those of people from control regions. Methods: We measured blood lead and cadmium levels and urine mercury and chromium levels and conducted a survey among 559 residents from the affected area and 347 residents of other areas. Results: Blood lead and cadmium levels and urine mercury levels were significantly higher in the case region than among those in the control region (p=0.013, p<0.001, p<0.001, respectively). In the thermoelectric power plant area, blood cadmium and urine mercury levels were significantly higher than in the control region (p<0.001, p<0.001, respectively). In the steel mill and petrochemical industry areas, blood cadmium level was significantly higher than that in the control region (p<0.001). Dividing groups by the reference level of blood cadmium ($2{\mu}g/L$), the odds ratios between the case and control regions were 2.56 (95% CI=1.83-3.58), 3.11 (95% CI=2.06-4.71) for the thermoelectric power plant area, 1.78 (95% CI=1.19-2.65) for the steel mill area and 4.07 (95% CI=2.40-6.89) for petrochemical industry area. Conclusion: This study showed that the levels of exposure to heavy metals among residents living near a Chungcheongnam-do Province industrial complex were significantly higher than those in the control region. This seems to be attributable to exposure to heavy metals emissions from the industrial complex. Further research and safety measures are required to protect residents' health.