earticle

한국어

In the case of spattered blood in bloodstain pattern analysis, the impact angle can be calculated by looking at the shape and size of it. The impact angle is a constant angle that occurs when the blood droplet touches the target surface, and the formula sin = W / L is used to calculate the impact angle. This formula is now used in the analysis of bloodstain patterns, and the results show that the error rate is about 18 % depending on the conditions. Nevertheless, since there is no formula to reduce the error rate, a new modification formula is being studied. In this study, the optimum impact angle calculation formula is derived from the wall surface where many scattered blood is found in crime scene in Korea and the error rate of the other impact angle calculation formula is compared. Currently, the use of wallpaper in Korea has a tendency to increase rapidly in silk wallpaper. However, the most cheap and easy-to-install wallpaper, which is still used the largest percentage, has been used as the target surface. Experimental results on the optimal angle of impact angle along the surface revealed that the optimal formulas were different for each surface and the -12 to 0 % error rate was observed when the optimal formula for one surface was applied to the other surface. Therefore, the optimal angle of impact angle should be applied differently depending on the surface, and accordingly, a database of optimal formulas for each surface is required. In the case of the laminated wallpaper, when the experimental condition for obtaining the optimized formula is not available, the improvement formula W / L = 0.9145 sin (0.02619? + 0.6478) + 0.5629 sin (0.04441? + 3.9020) will contribute to solve the case by deducing the correct impact angle value from the existing formula.