Recent space-based and balloon-borne experiments have shown various spectral features, including hardening of cosmic ray data at ~200 GeV/n in both primary and secondary elements, a positron excess above ~30 GeV, and a softening of the proton and helium spectrum at ~10 TV. The cause of these spectral features was investigated using GALPROP, a numerical cosmic-ray propagation code. The plain diffusion model with reacceleration and convection effects served as a baseline. Three cases were studied using rigidity-dependent parameters: a case with a diffusion coefficient break, a case with source spectrum breaks, and a case with a combination of both effects. An additional positron source was considered to describe this positron excess, and an additional proton and helium break was also considered to fit the softening of these spectra. Resulting elemental spectra and ratios are compared for the three cases. Implications of these spectral features are discussed.