1-FED will not review its interest rate on the upside before 1Q15.
2-BoJ is planning to reach it's Target.
Japan will release important figure this week that may affect the pair. therefore one should be very caution before entering the market.
Having said that, on a long term basis, BoJ and FED are planning to increase their interest rate and USD will win against Yen. But on a short term basis, if Japanese retail sales figure as well as household expenses and National Core CPI are within the expectation or even better, then USD may loose ground against JPY on a short terme basis.