The much discussed paradoxes of deontic logic , the so called Paradox of the Window, the Ross's Paradox and its variations, arise because the semantics of the standard systems of deontic logic contain a too weak concept of obligation. The paradoxes disappear if a stronger concept of obligation is used which takes into account that it cannot be demanded from a violator of a norm to fulfill the just violated norm in future. This idea can be formally realized by adding elements of temporal and modal logic to the deontic logic.