NEW YORK ( TheStreet) -- Do-it-yourself investors often have trouble finding the time to construct and manage their own portfolios.This reality may have led to the creation of the core-and-explore investing concept, where one puts a large portion of one's portfolio into funds that target broad indices such as the S&P 500 and a smaller portion into select themes, niches or countries, via individual stocks or specialized ETFs. I believe the recent flurry of low-volatility exchange-traded funds allows the core-and-explore concept to evolve into a more sophisticated end result for the DIY investor. The problem with the standard version of core-and-explore is that it relies on index funds such as the SPDR S&P 500 ( SPY), the PowerShares QQQ ( QQQ) and the iShares MSCI EAFE Index Fund ( EFA). The respective volatilities of these ETFs equal the market, because these funds essentially are the market. The more specialized "explore" funds tend to be more volatile than the broad market, so when investors layer them on top of the core index funds, they create an overall portfolio that is much more volatile than the market. Core-and-explore investors often don't realize how much volatility they have taken on until the market goes down a lot -- a bad time to make such a discovery. This is where the new low-volatility ETFs I mentioned come in. One broad market fund would be the PowerShares S&P 500 Low Volatility Portfolio ( SPLV). Since launching in May of this year this fund is up 3.8%, vs. a decline of 6.2% for the SPY. What's more, SPLV has been less volatile in delivering that result, which is a remarkable debut indeed. The dividends paid thus far by SPLV annualizes out to 3%, vs. 2% for SPY, although SPLV does not have enough of a track record for me to be confident in the 3% number.