Measurements of Parity-Violation Parameters at SLD

We present direct measurements of the parity-violation parameters $A_b$, $A_c$, and $A_s$ at the $Z^0$ resonance with the SLD detector. The measurements are based on approximately 530k hadronic $Z^0$ events collected in 1993-98. Obtained results are $A_b = 0.914\pm0.024$ (SLD combined: preliminary), $A_c = 0.635\pm0.027$ (SLD combined: preliminary), and $A_s = 0.895\pm0.066(stat.)\pm 0.062(sys.)$.