PURPOSES : In this study, a driving simulation testing equipment was developed to derive the optimal longitudinal tinting that can reduce the lateral vibration of the vehicle. Various types of longitudinal textures and tires were evaluated through simulation testing with the equipment. Based on the results, 3×3×16mm tinning as the optimal longitudinal texture was selected among 8 textures. METHODS : Based on the literature review, the causes of lateral vibration were analyzed, and parts and types for testing equipment development were reviewed. Driving simulation with testing equipment was conducted considering various textures and tires. To verify the test results, finite element analysis was performed under the similar conditions. And field test for two textures was conducted to find the optimal longitudinal texture. RESULTS : Based on the literature review, driving simulation test, finite element analysis and field test, longitudinal texture of 3×3×16mm is show the better performance compared to 7 textures. CONCLUSIONS : 3×3×16mm as longitudinal tinning for fresh concrete is show less lateral vibration than 3×3×12mm.

The purpose of this study was to understand the effects of mushroom occurrence by forest thinning in the Pinus koraiensis stand. The leaf area index, air temperature and relative humidity, soil water content, and amount of throughfall were measured in the P. koraiensis stand. The more throughfall of 72 mm / year and about 1 °C higher soil temperature were observed in the P. koraiensis stand than non-treatment stand. Relative humidity and soil water content were positively correlated with the occurrence of mushrooms in the P. koraiensis stand. The correlation coefficient of throughfall and ectomycorrhizal mushrooms was 0.93 in the thinned stand of P. koraiensis. 6 less species of ectomycorrhizal mushrooms and 7 more species of saprophytic mushrooms were observed in the thinned stand than in the non-treatment stand of P. koraiensis. Suillus pictus, an ectomycorrhizal mushroom, was found in a distribution of 100 pieces in the non-treatment stand and 69 pieces in the thinned stand of P. koraiensis. But the species diversity index of ectomycorrhizal mushrooms was 0.823 in the non-treatment stand and 0.911 in the thinned stand of P. koraiensis. In conclusion, forest thinning increased throughfall by decreased crown density. Accordingly it increased the number of ectomycorrhizal mushrooms. An increase of felled trees in the forest thinned sites caused an increase of saprophytic mushrooms.