What do investors suddenly see in Kohl's Corporation (NYSE: KSS)? Since November, the retailer's shares have soared more than 53%. Personally, I've never been great at discerning the sudden short-term sentiment shifts that can send a favored stock zipping up a weekly price chart. But it's clear that recent operational changes partially explain why investors are giving Kohl's a second look, after roughly three years of hand-wringing over its prospects in the retail sector.Kohl's has insulated itself from the online reach of both Amazon.com and Wal-Mart Stores (NYSE: WMT) by embracing e-commerce.