• Journal of Environmental Science International
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• v.21 no.3
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• pp.277-287
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• 2012

The MFFn(Mass First Flush) was analyzed for various rainy events(monitoring data from 2008 to 2009) in Transportation area(Highway, National road, Trunk road). Estimated MFFn using SWMM was evaluated by comparison with observed MFFn. MFFn was estimated by varying n-value from 10% to 90% on the rainy events. The n-value increases, MFFn is closed to '1'. As time passed, the rainfall runoff was getting similar to ratio of pollutants accumulation. The result of a measure of the strength of the linear relationship between observed data and expected data under model was good ($R^2$=0.89). Pollutants runoff loads by volume showed Highway 26.6%, National road 44.8%, Trunk road 35.0% at the MFF20(20% by total runoff). A case of MFF30, pollutants runoff loads by volume showed Highway 40.2%, National road 54.3%, Trunk road 46.8%. According to the results, Initial precipitation basis were Highway MFF30, National road MFF20, Trunk road MFF30 when the Non-Point source control facilities set up.

• Journal of Ecology and Environment
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• v.44 no.4
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• pp.207-211
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• 2020

Adult land crabs generally live on land while their larvae live in the sea. In the case of Sesarma haematoche, female crabs migrate from land to sea to release the larvae at the high tide of syzygy night. Artificial structures along coastal areas are being obstacles for the migration of land crabs and causing synchronized roadkills on coastal roads during breeding migration. In this research, we compared the sex ratios of crab populations in coastal areas with coastal roads and uninhabited island areas with no road. The proportion of females in inland habitats with coastal roads was significantly smaller than island habitats. In particular, females are exposed to the risk of annually repeated roadkills, and the proportion of females decreases rapidly with their growth. If this tendency is general for land crab populations in the coastal areas with roads, significant road mortality of female land crabs during breeding migration can lead to severe population decline in coastal areas. Therefore, it is necessary to take an action to save land crabs crossing coastal roads.

• Journal of The Korean Society of Agricultural Engineers
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• v.46 no.1
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• pp.35-40
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• 2004

This study is performed to examine the physical and mechanical properties of eco-concrete using soil, natural coarse aggregate, excellent soil compound and polypropylene fiber. The test result shows that mass loss ratio is decreased with increasing the content of coarse aggregate and excellent soil compound. The compressive and flexural strengths are increased with increasing the content of coarse aggregate, excellent soil compound and polypropylene fiber. The coefficient of permeability is decreased with increasing the content of coarse aggregate and excellent soil compound, but it is increased in 0.2% polypropylene fiber content. The lowest coefficient of permeability is showed in $5.066\times 10^{-9}$cm/s. These eco-concrete can be used for farm road.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.7
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• pp.567-574
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• 2002

In the present study, ventilation flow rates and pressure rises through a road tunnel are simulated numerically using CFD with the various conditions such as roughness height, swirl angle of jet fan, entrance and exit effect and hub to tip ratio. By using a modified wall function, friction factor can be predicted under 10％ of error with respect to the Moody chart for the circular pipe flow and 15％, for the present tunnel. For more precise design, the effects of the swirl angle and hub to tip ratio of jet fan, which is not included in the theoretical equation of pressure rise by jet fan are necessary to be considered.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05c
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• pp.261-264
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• 2003

In this paper, a disk-type piezoelectric transformer for the high power was investigated with the variation of road resistance. The diameter and thickness of a disk-type piezoelectric transformer was 45mm and 4mm, respectively. The piezoelectric ceramics was composed to PZT-PMN-PSN. The ratio of driving electrode and generating electrode is 2:1. The poling direction of driving part and generating part are the same. A voltage step-up ratio increased with increasing the load resistance, $R_L$, so it reached 60 under no road resistance. Also, the maximum efficiency of 97% was obtained.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.353-356
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• 1997

Vehicle steering system determines the direction of a vehicle. A manual steering system consists of mechanical connections between the steering wheel and tires. Recent power steering system adds an actuator to help a driver to steer easily at low speed. However, at front collision, the driver can be injured by steering shaft and the power steering pump decreases the engine power. To solve these problems, electronic power steering system which connects the steering wheel and tires with electronic connection is proposed, that has advantages such as decrease of engine load and increase of driver safety reactive. Since the ratio between driver's steering torque and steering torque of tires can be controlled freely, the torque which is delivered from the road to the driver through tires and steering wheel can be reshaped to make the driver feel comfortable. In this paper, the ratio of delivering steering torque and the magnitude of force to be delivered from road to driver has been controlled using fuzzy controller, and it's effectiveness has been shown through simulation results.

• Journal of the Korean Applied Science and Technology
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• v.38 no.6
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• pp.1355-1369
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• 2021

This study improved the algorithm for the road ice prediction algorithm and analyzed the prediction rate when comparing actual field measurement data and algorithm prediction value. For analysis, road and weather conditions were measured in Geumdong-ri, Sinbuk-myeon, Pocheon-si. First algorithm selected previous research result algorithm. And the 4th algorithm was improved according to the actual freezing conditions and measured values. Finally, five algorithms were developed: freezing by condensation, freezing by precipitation, freezing by snow, continuous freezing, and freezing by wind speed. When forecasting using an algorithm at the Pocheon site, the freezing hit rate was improved to 93.2%. When calculating the combination ratio for the algorithm. the algorithm for freezing due to condensation and the continuation of the frozen state accounted for 95.7%.

• Journal of ILASS-Korea
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• v.25 no.4
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• pp.178-187
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• 2020

The current emission regulations, US Tier-4 and EU Stage-V, are only able to satisfy the regulations when all currently mass-produced emission reduction technologies such as EGR, DOC, DPF, and SCR are applied. Therefore, in this study, for the application of the Urea-SCR system to non-road diesel engines, the database was established by measuring the NO, NO2 concentration and calculating the NO2/NOx ratio based on the catalyst temperature and exhaust mass flow rate. Also, based on the measured NO2/NOx ratio data, a mathematical model was proposed to predict the NO2/NOx ratio at SCR catalyst, and the suitability of the model was verified through steady-state and transient mode. As a result of comparing the NO2/NOx ratio measured at the DOC outlet under the steady-state condition to two model values separately, the R2 was 0.9811 for the 3D map model and 0.9303 for the mathematical model. And in the case of the NO2/NOx ratio measured at the DPF outlet, the R2 was 0.9797 for the 3D map model and 0.935 for the mathematical model. It was confirmed that the R2 with the model value of the 3D Map of the mathematical model in the transient mode is 0.957, which shows high reliability.

• 한국도로학회:학술대회논문집
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• 2010.03a
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• pp.113-118
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• 2010

• Journal of Korean Society of Forest Science
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• v.84 no.4
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• pp.517-524
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• 1995

This study was conducted to investigate the characteristics of the road alignment, correlations among evaluation factors of the alingment, and the relationships between the evaluation factors and terrain factors for the forest road of five National Forest Offices. The results were as follows : 1. The elongation coefficients(${\eta}$) of forest road in Kangnung and Wonju National Forest Office were ranged 0.3~0.5, and those of Andong, Namwon, and Kongju National Forest Offices were ranged 0.2~0.3 in straight line of 100m, 200m, and 300m. 2. Three different types of plane alignment were identified for Kangnung and Wonju National Forest Offices, Namwon and Kongju National Forest Offices, Andong National Forest Office. However, longitudinal alignment for five National Forest Offices tended to be similar conditions. 3. Low correlation coefficients were calculated in the relation between elongation coefficients(${\eta}$) and evaluation factors of plane alignment(curve length ratio(%), sum of inverse number of each curve radius(m/km), and sum of each intersection angle($^{\circ}/km$)) for three straight lines. On the contrary, high correlation coefficients were obtained among the relations of curve length ratio(%), sum of inverse number of each curve radius(m/km), and sum of each intersection angle($^{\circ}/km$). 4. Slope(%) were closely correlated with plane alignment, and so were the relationships between frequency of valleys and streams(No./km) and elongation coefficients(${\eta}$) of forest road.