• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.9-20
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• 2019

The number of natural disasters in Korea, such as earthquakes, is increasing. As a result, there is growing need for temporary residences or shelters for disaster conditions. The aim of this study was to produce post-disaster refugees housing differentiated from existing shelters using lightweight composite panels. To accomplish this, the structural performance of lightweight composite panels was validated, and an in-plane shear strength test was conducted according to the ASTM E72 criteria among the performance test methods for panels. As a result of the experiment, the maximum load for each specimen under an in-plane shear load was determined. All the experiments ended with the tear of the panel's skin section. The initial stiffness of the specimens was consistent with that predicted by the calculations. On the other hand, local crushing and tearing, as well as the characteristics of the panel, resulted in a decrease in stiffness and final failure. Specimens with an opening showed a difference in stiffness and strength from the basic experiment. The maximum load and the effective area were found to be proportional. Through this process, the allowable shear stress of the specimens was calculated and the average allowable shear stress was determined. The average ultimate shear stress of the lightweight composite panels was found to be $0.047N/mm^2$, which provides a criterion of judgement that could be used to expect the allowable load of lightweight composite panels.

• Journal of the Korean Geotechnical Society
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• v.35 no.4
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• pp.15-26
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• 2019

The stability of the gravity quay wall against earthquakes is evaluated on the basis of the allowable displacement of the wall. To estimate the displacement caused by external forces, empirical equations based on the Newmark sliding block method or numerical analysis are widely used. In numerical analysis, it is possible to analyze precisely a complicated site and structure, but difficult to set the appropriate parameters and environments; there are limitations in obtaining reliable results, depending on one's level of expertise. The Newmark method, with only seismic motions, is widely used because it is simpler than numerical simulations when estimating permanent displacement. However, the empirical equations do not have any parameters for the response characteristics and sliding block of the structure, and sliding blocks being assumed as rigid bodies does not consider the nonlinear behavior of the soil and interaction with the structure. Therefore, in order to evaluate the seismic stability of the gravity quay wall, a newly-developed empirical equation is needed to overcome the above-mentioned limitations. In this study, numerical simulations are performed to analyze the response characteristics of the backfill of the structure, and to propose an optimal method of calculating the active area. For this purpose, finite element analyses were performed to analyze the response characteristics, and stress-strain relationships for various seismic motions. As a result, the response characteristics, sliding block, and failure surface of the backfill vary depending on the input seismic motions.

• Journal of the Korean Geosynthetics Society
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• v.17 no.4
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• pp.21-28
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• 2018

Despite a number of studies on consolidation behavior that have been carried out in the Nakdong River estuary in Busan, these are focused on the prediction of final settlement during ground improvement process, and there is almost no research on the long-term settlement occurring after that. For the practical study on the long-term settlement, the field monitored settlement data that measured over 10 years in the Busan new port facilities area were used, and the final settlement and predicted time-settlement line were constituted by hyperbolic function. As a result, the measured settlements depend on the thickness of clayey soils, and the pattern were similar to each other and good agreement with the predicted time-settlement line using hyperbolic method. Also, the settlement in the lower non-improved layer occupied 62-76% of total settlement. Information about above results would be quite helpful to understand the long-term settlement behaviors as well as the non-improved layer's settlement is more careful consideration needed at design phase.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.5
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• pp.535-541
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• 2019

The purpose of this study was to investigate the possibility of fishery in offshore wind farms and evaluate the risk linked to the presence of turbines and submarine cables in these areas. With this objective, we studied an offshore wind farm in the Southwest Sea and the current state of vessels in the surrounding National Fishing Port. The risk assessment criteria for 22 fishing gears and methods were set by referring to the fishing boats; thereafter, the risk was assessed by experts. The fishing gears and methods that could be safely operated (i.e., associated with low risk) in the offshore wind farm were: single-line fishing, jigging, and the anchovy lift net. The risk was normal so that it is possible to operate, but the fishing gears and methods that need attention are: the set long line, drifting long line, troll line, squid rip hook, octopus pot, webfoot octopus pot, coastal fish pot, stow net on stake, winged stow net, stationary gill net, and drift gill net. Moreover, the fishing gears and methods difficult to operate in the of shore wind farm (i.e., associated with high risk) were: the dredge, beam trawl, and purse seine. Finally, those associated with very high risk and that should not be allowed in offshore wind farms were: the stow net, anchovy drag net, otter trawl, Danish seine, and bottom pair trawl.

• Journal of Applied Biological Chemistry
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• v.62 no.3
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• pp.219-228
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• 2019

This study summarized processing factor (PF) by the stage of rice and barley processing based on JMPR reports from 2006 to 2016. We compared PF of 17 pesticides in rice products during the processing of rice grain, husked rice, polished rice, hulls, bran and cooked rice. Among the 17 pesticides, 12 pesticides except for 5 pesticides such as acephate, methamidophos, glufosinate, quinclorac and sulfoxaflor mostly decreased in pesticides when rice grain processed into brown rice. Pesticides tended to be partially reduced when processed from husked rice to polished rice. However, hulls and bran produced during the milling process were concentrated. Acephate and others, 5 pesticides are systemic pesticides, and pesticides are penetrated into foods, and a large amount of pesticides was not removed during the milling process. The remaining pesticide residues in polished rice were mostly removed after processing into cooked rice, and trace amounts of pesticide residues remained. In the comparison of 23 pesticides PF during the processing of barley products (pearl barley, flour, short, malt, beer, hulls and bran). Most of the pesticide except for 4 pesticide (ethephon, pyraclostrobin, penthiopyrad, sulfoxaflor), which are systemic pesticides, decreased during the process of pearl barley production out of the barley grain. The pesticide in the malt, which was made by steeping pearl barley was concentrated but when processed into beer, pesticide was remained only in trace amounts.

• Informatization Policy
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• v.26 no.1
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• pp.83-105
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• 2019

The purpose of this study is to analyze the domestic and overseas laws and regulators' decisions related to zero-rating (ZR) practices through a comparative approach and to support development of the ex-post regulation. Although most countries are adopting ex-post regulatory approaches toward the globally increasing ZR practices, there is no uniform standards or an approach to consider when deciding whether to allow mobile ISPs' zero-rating practices in the market. However, in recent years, some countries have been improving their policy transparency with respect to ZR through enacting and amending relevant laws as well as making trial decisions. The comparative analysis shows that each country investigates restriction of the user choice and ISPs' adherence to the obligation of non-discrimination in order to judge whether the user benefits are damaged by the ZR practices. It also investigates ISP-CP's market positioning and ISP's vertical integration for profit squeeze to find out whether they harm fair competition with ZR practices in the mobile ecosystem. Based on the results of the comparative analysis, we suggest the desirable ZR regulatory directions under the domestic legislative status.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.694-701
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• 2018

Larger crack widths can be observed more in FRP-reinforced concrete members than in steel-reinforced concrete members as a result of the lower elastic modulus and bond strength of FRP reinforcement. The ACI 440.1R-15 design guide provides equations derived as the maximum bar spacing to control the crack widths indirectly. On the other hand, it is not concerned with long-term effects on the crack control design provisions. This study provides suggestions for how to incorporate time-dependent effects into the crack width equation. The work presented herein includes the results from 8 beams composed of four rectangular and T-shaped FRP-reinforced concrete beams tested for one year under four-point bending. Over a one year period, the crack widths increased as much as 2.6~3.0 times in GFRP and AFRP-reinforced specimens and 1.1~1.4 times in the CFRP-reinforced specimens compared to steel-reinforced specimens. In addition, the average multiple for crack width at one year relative to the instantaneous crack width upon the application of the sustained load was 2.4 in the specimens with a rectangular section and 3.1 in the specimens with a T-shaped section. As a result, it is recommended conservatively that the time-dependent coefficient be taken as 2.5 for the rectangular beams and 3.5 for T-beams.

• Journal of the Korean GEO-environmental Society
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• v.22 no.2
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• pp.35-39
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• 2021

Photogrammetry using drone can produce high-resolution ortho image and acquire high-accuracy 3D information, which is useful. Therefore, this study attempted to determine the possibility of using drone-photogrammetry in park construction by producing a topographic map using drone-photogrammetry and analyzing the problems and accuracy generated during production. For this purpose, we created ortho image and DSM (digital surface model) using drone images and created topographic status map by vectorizing them. Accuracy was compared based on topographic status map by GPS (global positioning system) and TS (total station). The resulting of analyzing mean of the residuals at check points showed that 0.044 m in plane and 0.066 m in elevation, satisfying the tolerance range of 1/1,000 numerical maps, and result of compared lake size showed a difference of about 4.4%. On the other hand, it was difficult to obtain accurate height values for terrain in which existed vegetation when producing the topographic map, and in the case of underground buried objects, it is not possible to confirm it in the image, so direct spatial information acquisition was necessary. Therefore, it is judged that the topographic status map using drone photogrammetry can be efficiently constructed if direct spatial data acquisition is achieved for some terrain.

• Journal of the Korean GEO-environmental Society
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• v.12 no.7
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• pp.23-29
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• 2011

The oxidation slag has been widely used in civil engineering project, whereas the reduced slag from electric furnace has yet to be applied. Consequently in order to find out the recycling method in civil engineering field, the mineral compositions of the reduced slag were analyzed and some tests on water quality were performed to estimate the potential release of toxic compounds. Slag-soil mixtures of 0, 10, 20 and 30%(dry weight) soil were prepared in lysimeter columns and the effluents were collected with the period of one, two and four week options in closed system, respectively. The result from qualitative and quantitative analysis using X-ray Diffraction(XRD) and X-ray Fluorescence(XRF) indicates that the main mineral of the reduced slag is $Ca_2(SiO_4)$, a kind of calcium silicate. Also, the leaching medium analyzed by Inductively Coupled Plasma Optical Emission Spectroscopy(ICP-OES) showed that main heavy metals such as Al, Fe and Mn are included in the reduced slag due to the effect of steel production process. It can be seen that the leachate does not violate the regulation guide line of waste material of heavy metal. Also the pH levels were increased from pH 6.9 for 0% soil to pH 10 for 30% soil. However the influence on leachate circulation period of one through four weeks was negligible.

• Journal of Legislation Research
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• no.55
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• pp.193-237
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• 2018

The recent surge in the ISD lawsuit filed against the Korean government is likely to cause major domestic confusion. This is because in most cases, foreign investors have claimed billions of won in damages filed against Korea in the ISD lawsuit. Public opinion will be generated to abolish the ISD lawsuit system, which is included in the international investment agreement, when a decision comes out in the Elliott/Mason case or Lone Star case, which has already been completed by the hearing. It is clear that the ISD clause, which is commonly included in most of the BITs, FTAs, can be a limiting factor in the government's public policy, as shown by many investment disputes. However, it is not necessary to have a negative view of the ISD clause itself, given that it is a system that can protect Korean investors from illegal and inappropriate actions by local governments. Since Korea already allows the system of ISD lawsuits with many countries through FTAs and BITs, and negotiations are underway to sign FTAs with new countries, the possibility that foreign investors will refer to the ISD proceeding further to our government's public policy will increase. In order to prepare for an ISD lawsuit, the Korean government has launched a response team consisting of government practitioners, private scholars, and legal professionals in the central government ministries to review major legal issues that are controversial in the cases of the ISD. In particular, local governments and public institutions, which fail to recognize the importance of international investment regulations and ISD clause, need to share and train relevant information so that all processes for public policy planning and implementation comply with international investment rules such as BITs and FTAs.