A processing element may include a pre-processing circuit configured to receive and filter a feature and a weight and output a filtered feature and a filtered weight; and an accumulation circuit configured to accumulate a value of the filtered feature, wherein the pre-processing circuit comprises: a sign conversion circuit configured to change a sign of the feature and a sign of the weight when the weight having a value of −1; and a zero filtering circuit configured to change a value of the weight to 0 when the feature having a value of 0.