• Journal of the Korea Institute of Building Construction
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• v.12 no.4
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• pp.377-385
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• 2012

In this study, the Impact resistance of steel fiber and organic fiber reinforced concrete and mortar was evaluated and the improvement in toughness resulting from an increase in compressive strength and mixing fiber for impact resistance on performance was examined. The types of fiber were steel fiber, PP and PVA, and these were mixed in at 0.1, 0.5 and 1.0 vol.%, respectively. Impact resistance is evaluated with an apparatus for testing impact resistance performance by high-speed projectile crash by gas-pressure. For the experimental conditions, Specimen size was $100{\times}100{\times}20$, 30mm ($width{\times}height{\times}thickness$). Projectile diameter was 7 and 10 mm and impact speed is 350m/s. After impact test, destruction grade, penetration depth, spalling thickness and crater area were evaluated. Through this evaluation, it was found that as compressive strength is increased, penetration is suppressed. In addition, as the mixing ratio of fiber is increased, the spalling thickness and crater area are suppressed. Organic fibers have lower density than the steel fiber, and population number per unit area is bigger. As a result, the improvement of impact resistance is more significant thanks to dispersion and degraded attachment performance.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.161-162
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• 2018

In this study, it evaluate the impact resistance of UHPC by repeated impact. smooth steel fiber and polyvinyl alcohol fiber were reinforced in UHPC respectively. Overall, the impact resistance of the specimens reinforced with 0.4vol.% PVA fiber was high, and the crater diameter was small in specimens using 13mm fiber. When 19 mm steel fiber is used, the fracture depth is small due to the increase of macro crack resistance compared with other specimens. On the other hand, in the case of the fracture area, it is considered that the use of the fiber of 13 mm causes an increase in the stress dispersion effect to occur small.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.10a
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• pp.196-203
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• 2000

In this study, the evaluation method of diffusion characteristics of Suspended Soli&SS) and the generation limit(source and thick) are investigated, which is significantly affecting on marine examined by construction works such as dredging and reclamation. Dispersion characteristics of SS is examined by hydraulic tests and numerical works in consideration with the Pusan Port. Hydraulic model test was performed in 2-D wave flume to find the limit wave conditon of re-suspension of solid as well as the time dependent characteristics of settlement The results obtainded in the study are as follows; 1) The quantituative evaluation af SS is the basic parameter of marine environmental impact assessment in related with the port development The SS increases as the water content of sea bed solid increases and the density decreases. 2) The sea bed solid in Sinsundai area, Pusan Port has the water content range of 83~157% 3) The ratio of suspension velocity against settlement velocity is about 0.25 and SS concentration converges as the wave heigh. 4) The SS increases 2 time when time step increases 3 time(10 sec to 30 sec) in numerical simulation It means that the effect of the time step should be checked in detail to stable. The diffusion The diffusion coefficient are Affiected senstively in the dispersion process while sea ved friction coefficinet have not strong relation in the simulated area

• Journal of Environmental Impact Assessment
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• v.22 no.6
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• pp.547-556
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• 2013

Recently, golf courses have increased over the years because golf became popular leisure sport. Various environmental problems have been then issued by a golf course during constructing and running them. A problem of pesticide, which is serious among various environmental problems, from golf course has harmful effect on surrounding area and makes human suffer from acute and chronic diseases. Pesticides are used for the cost-effective managing of golf course and the amount of pesticides also increases as the number of golf course increase. Since the assessment of pesticides on near-by surrounding has been focused on water and soil media, studies related to atmospheric dispersion have been hardly attempted. The method to assess an impact of pesticide nearby agricultural production by the atmospheric dispersion using AGDISP(AGricultural DISPersal) model was developed and applied to the actual planned golf course located in Hongcheon, Gangwon. For implementing AGDISP, parameters were investigated from the golf course's land use planning map, pesticide spray device, Hong-Cheon weather station and etc. First of all, a kind of pesticide, a form of spraying pesticide, geographical features, weather data, and distance(golf course to plantation) were investigated to understand how to work these parameters in AGDISP. Restricted data(slope angle, droplet size distribution and solar insolation) sensitivity analysis of these parameters to estimate effect of pesticide nearby a plantation and a high relative contribution data of analyzed data was selected for input data. Ethoprophos was chosen as the pesticide used in the golf course and the amounts of pesticide deposition per annual agricultural productions were predicted. The results show that maximum amount of pesticide deposition through atmospheric dispersion was predicted $2.32{\mu}/m^2$ at 96 m where the nearest organic plantation exists. The residues of pesticide were also estimated based on the annul production of the organic and the deposition amount of the pesticide. Consequently, buckwheat, wheat and millet were likely to exceed maximum residue limits for pesticides in foods(MRL) and sorghum, corn and peanut were likely to exceed MRL by organic farming as well.

• Journal of information and communication convergence engineering
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• v.15 no.3
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• pp.165-169
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• 2017

Altmetrics is an emergent research area whereby social media is applied as a source of metrics to evaluate scientific impact. Recently, the interest in altmetrics has been growing. Traditional scientific impact evaluation indictors are based on the number of publications, citation counts and peer reviews of a researcher. As research publications were increasingly placed online, usage metrics as well as webometrics appeared. This paper explores the potential benefits of altmetrics and the deep relationship between each metrics. Firstly, we found a weak-to-medium correlation among the 11 altmetrics and visualized such correlation. Secondly, we conducted principal component analysis and exploratory factor analysis on altmetrics of social media, divided the 11 altmetrics into four feature sets, confirming the dispersion and relative concentration of altmetrics groups and developed the altmetrics evaluation model. We can use this model to evaluate the scientific impact of articles on social media.

• Journal of Environmental Impact Assessment
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• v.5 no.1
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• pp.61-67
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• 1996

Environmental Impact Assessment (EIA) in Korea has worked toward environmental conservation and decision making since the Environmental Impact Statement of 1981. In order to implement the EIA process effectively, we have developed a system for and various methods of EIA. Among these methods, the Geographic Information System (GIS), which was introduced recently in Korea, can be used to integrate geographic and attribute data effectively. So GIS begins to increase the necessity of the application in EIA process. This study includes the integration method of the GIS and air dispersion model on the odor impact assessment of $NH_3$ emission in landfill sites. First, it computes surface values by grids using the Digital Elevation Model (DEM). Second, it presents predicted data considering topography and climate by grids. Third, it shows the overlaying analysis of the administrative map including population and odor predictive data. The results could systematically analyze impact areas, and assess residential impact by alternatives. Integration analysis of the air predictive model and GIS as a residential area assessment can support negotiations of public and proponent in EIA.

• Journal of Environmental Impact Assessment
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• v.31 no.5
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• pp.271-285
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• 2022

The AERMET, the AERMOD meteorological preprocessing program, mainly used for environmental impact assessment and Integrated Environmental Permit System (IEPS) in Korea, has not considered the land covers characterasitics, and used only the past meteorological data format CD-144. In this study, two results of AERMET application considering CD-144 format and ISHD format, being used internationally, were compared. Also, the atmospheric dispersion characteristics were analyzed with consideration of land cover. In the case of considered the CD-144 format, the actual wind speed was not taken into account in the weak wind (0.6~0.9m/s) and other wind speed due to the unit conversion problem. The predicted concentration considering land cover data was up to 387% larger depending on the topographic and emission conditions than without consideration of land cover. In conclusion, when using meteorological preprocessing program in AERMOD modelling, AERMET, with ISHD format, land cover characterasitics in the area should be considered.

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.5
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• pp.712-719
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• 2012

Penetrator with enhanced lateral effect(PELE) is a newconcept projectile, without dynamite and fuze. It consists of high-density jacket, closed at its rear end and filled with a low-density filling material. To study the explosion characteristics of PELE, by AUTODYN-3D code, the calculation models of projectile body and bullet target are established and the process of penetrating aluminum-2024 alloy target of PELE is simulated, and the scattering characteristics after penetrating aluminum-2024 alloy target of PELE are studied by different initial velocity. The explicit finite element analysis of PELE fragmentation was implemented with stochastic failure criterion in AUTODYN-3D code. As expansion of filling, the fragments were obtained velocities and dispersed laterally and further more enhancing the damage area largely. The number and shape of the PELE fragments were different depend on impact velocity and incidence angle of filling which fragment generated during penetration and lateral dispersion process.

• Journal of Environmental Science International
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• v.18 no.10
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• pp.1103-1114
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• 2009

In this study, the environmental behavior of malodor pollutants (MPs: $H_2S$, $CH_3SH$, DMS, and DMDS) was investigated around areas influenced by strong anthropogenic processes based on observations and modeling study (a CALPUFF dispersion model). The MP emission concentrations were measured from 8 industrial source regions (tire plants (S1-S3), waste water disposal plant (S4), and oil refinery (S5) in an urban center area and paper mill/incineration plant (S6) and livestock feedlots (S7-S8) in Ungsang area) in Yangsan city during a fall period in 2008 (21 October 2008). Overall, the most MPs emitted from the urban center area were found to affect the malodor pollution in their downwind areas during early morning (06:00 LST) and nighttime (18:00 and 21:00 LST), compared with those in the Ungsang area. For malodor intensity, the most MPs in the urban center area (especially S1 and S2) were found to be a significant contributor, whereas $CH_3SH$ and $H_2S$ in the Ungsnag area (especially S6) were the dominant contributor. The model study showed agreement in the spatial distributions of simulated MPs with those of the observations. The largest impact of MPs in the urban center area on the malodor pollution in its residential areas occurred at S1, S2, and S3 sites during nighttime, while that of MPs in the Ungsang area occurred at S6 and S8 sites. This may be caused mainly by the high MP emissions and in part by wind conditions (prevailing northeasterly winds with low wind speeds of 2-3 m/s).

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.2
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• pp.143-156
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• 2014

We reviewed investigation status on turbidity plume in the statement of marine environmental survey(2008 to 2012) associated with marine sand extraction projects. The survey statement from seven marine sand extraction sites (extraction area of Southern EEZ, extraction area of Western EEZ, relocation zone in the Western EEZ, sea area under jurisdiction of Taean-gun, sea area under jurisdiction of Ansan City, and two discrete sea areas under jurisdiction of Ongjin-gun) in the nearshore and offshore of Korea showed that in situ observations were carried out for the dispersion and transport of suspended sediments on two areas (One is a extraction area in the EEZs, the other is an area of coastal sites). However, sampling station and range have not been selected considering physical, geographical factors (tide, wave, stratification, water depth, etc.) and weather conditions (wind direction and velocity, fetch, duration, etc). Especially turbidity plumes originating from three sources, which include suspended sediments in overflow(or overspill) discharged from spillways and reject chutes of dredging vessel, and resuspended sediments from draghead at the seabed, may be transported to a far greater distance outside the boundary of the extraction site and have undesirable impacts on the marine environment and ecosystem. We address that behaviour of environmental pollutants such as suspended solids, nutrients, and metals should be extensively monitored and diagnosed during the dispersion and transport of the plume. Finally we suggest the necessity to supplement the current system of the sea area utilization consultation and establish the combined guidelines on marine sand extraction to collect basic data, to monitor cumulative effects, and to minimize environmental damages incurred by the aftermath of sand extraction.