• International Journal of Highway Engineering
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• v.11 no.2
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• pp.45-54
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• 2009

Despite vehicle instability problems caused by gusts of wind on freeways located in mountain or seaside areas, current national highway design standards overlook their detrimental effects, and if higher design speed freeways being proposed now by the government are in operation, the strong effect of the gust of wind becomes a highway alignment design issue. This paper presents the vehicle movements and their resulting safety effects by checking vehicle sliding and overturn based on vehicle dynamic analysis for the case when a gust of wind blows to vehicles negotiating curves on higher speed freeways. In this analysis, vehicle types, curve radii, motorist responsive time to vehicle driving path changes, and vehicle speeds are systematically arranged to get vehicle sliding and overturn values in each different conditions. The results showed that there were little overturn possibilities when wind speed would stay in 50m/sec with higher than 600 meter curve radii. Interestingly it was also found in sliding checks that, although being safe at less than 15.0m/sec wind speed levels, there appeared the need of vehicle travel prohibitions when the wind speed could exceed 25.0m/sec level. The findings in this research is of information in future higher speed freeway designs, and particularly useful when designing freeways passing frequent gust wind areas.

• The Korean Journal of Applied Statistics
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• v.29 no.5
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• pp.849-858
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• 2016

It is important to control confounding bias when estimating the causal effect of treatment in an observational study. We illustrated that the covariate selection in the causal inference is different from the variable selection in the ANCOVA model. We then investigated the three criteria of covariate selection for controlling confounding bias, which can be used when we have inadequate information to draw a complete causal graph. VanderWeele and Shpitser (2011) proposed one of them and claimed it was better than the other two. We show by example that their criterion also has limitations and some disadvantages. There is no clear winner; however, their criterion is better (if some correction is made on its condition) than the other two because it can remove the confounding bias.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.1
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• pp.45-51
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• 2015

PBDEs (polybrominated diphenyl ehters) are rarely dissolved in water due to their strong hydrophobicity and large molecular mass so not many researches were done in aqueous environment compared to other environmental compartments. However, the mass loading from wastewater treatment plant into aquatic environment, re-suspension from bottom sediment and partitioning from floating particles and colloids may not be negligible. It is, therefore, important but also difficult to investigate PBDEs in water environment. Recent overcoming resolution towards this barrier to monitor hydrophobic organic compounds in aquatic environment is using passive sampling technique like semipermeable membrane device. By using passive sampling, it might be possible to obtain long-term reproducible monitoring result and detect the trace amounts of PBDEs, with controlling fluctuation of surrounding environmental factors during the sampling event. So therefore, this study is purposed to confirm the possibility of using SPMD (semi-permeable membrane device) as water monitoring tool. Grab samples, composite samples and SPMDs were applied in river bank to evaluate the concentration difference and temporal fluctuation by various water sampling method, and to assess the water concentration prediction capability of SPMD for the PBDEs.

• Korean Journal of Food Science and Technology
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• v.48 no.4
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• pp.317-322
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• 2016

A pesticide mix solution containing difenoconazole, lambda-cyhalothrin, and lufenuron was applied 3 times on field grown chili pepper at a fivefold overdose dilution concentration of the spray solution at a pre-harvest interval of 7 day. Difenoconazole, lambda-cyhalothrin, and lufenuron were detected at 4.43, 0.334, and 1.56 mg/kg, respectively, in raw chili pepper. Washing with water reduced the residue levels to 91.4, 94.3, and 85.3%, respectively. In dried chili pepper, the residues of difenoconazole, lambda-cyhalothrin, and lufenuron were 22.2 mg/kg (processing factor, Pf =5.01), 1.65 mg/kg (Pf =4.94), and 6.54 mg/kg (Pf =4.19). In the seeds, difenoconazole and lambda-cyhalothrin were not detected, and lufenuron was detected at 0.0075 mg/kg (n=1) and <0.005 mg/kg (n=2). Thus the pesticide residues in the seeds was negligible. In the seed oil, difenoconazole and lufenuron residues were 0.0263 and 0.0295 mg/kg, respectively (concentration factors=5.26 and 4.72). These concentration factors supported the theoretical concentration factor of 6.8, assuming that all of compound present in the seed are transferred into the oil.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.9 no.2
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• pp.120-128
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• 1976

Two experiments were conducted to study the nature of protein degradation in fish muscle postmortem, first one with English sole (Paraphyrus vetulus) followed by another with rockfish (Sebastodes spp.). In the first one, proteolysis was measured by the increase of amino-N in gutted fish during storage in ice and in the homogenates prepared from fish of different ice storage during $20^{\circ}C-incubation$. In order to test the possible involvement of fish muscle a cathepsin, a portion of each homogenate sample was exposed to 0.5 Mrad of gamma radiation to destroy viable microorganisms prior to the incubation. Proteolysis was not detected until viable count reached a level above $10^7$ cells per gm fish flesh, corresponding to 31 days of ice storage. Even if fish flesh were mechanically disrupted by means of homogenization and subsequently incubated at $20^{\circ}C$, proteloysis attributable to muscle cathepsin was not detected. In the second with rockfish muscle aseptically prepared from freshly killed fish, the samples were inoculated with a proteolytic strain of fish spoilage Pseudomonad or irradiated at 0, 0.5 and 3.0 Mrad. The four samle groups were stored at $0-2^{\circ}C$ to compare the spoilage pattern of sterile and non-sterile muscle. In sterile muscle both total-N (extracted in 0.5M KCl) and amino-N $(soluble\;in\;70\%\;ethanol)$ declined slightly while the inoculated muscle showing increase in parallel with the increase of number of inoculated bacterium. The results indicate that proteolysis is a part of normal fish spoilage and the onset of proteolysis is delayed until viable count reaches its maximum level. Contribution of fish muscle cathepsin to protein degradation in white flesh fish muscle post-mortem is nil.