earticle

영어

Various types of bloodstain are found at criminal scenes in which bloodshed is involved. The impact angle from the ejection point of a falling bloodstain to the final surface may be estimated using the length of the long axis and the short axis of the bloodstain. The blood origin of an impact spatter bloodstain may be estimated by calculating the impact angle. The equation for calcul ating the impact angle may help to reconstruct a criminal scene. The conventional equation for calculating the impact angle is sina· = W/L, which is based on a general trigonometric function. Some studies have shown that the impact angle calculated using the conventional equation is different from the actual impact angle, but almost no study has been conducted to coiTect the equation. In the present study, an improved equation for calculating the impact angle was derived on the basis of impact angle experiments, and the error rates of the conventional equation and the improved equation were calcul ated. The improved equation is as follows W/L = 1.590 sin(0.009517a- 0.02887) A comparison of the impact angle calculated using the conventional equation and the improved equation with the actually measured impact angle showed that the error rate of the improved equation was significantly lower. Therefore, in a situation in which an impact angle of a bloodstain needs to be calculated for a criminal scene involving bloodshed, the improved equation provided in the present study may help to estimate the impact angle more accurately.