On the basis of the configuration characteristics of man-made forests, the spread model of wireless sensor signal in man-made forests has been simplified according to electromagnetic wave theory and Fermat principle. The man-made forests is decomposed into independent medium with four layers, the spread model is simplified into free space model, attenuation screen model and absorption screen mo...

death has been and is the most important problem of human being throughout the history. every man is innately in the pursuit of immortality, life and well-fare as they also hate destruction and annihilation. this problem as well as related views and analyses of the true nature of death, the elements of reducing the dread of death have all direct effect on meaningfulness of life. whether or not ...