Double), (String, Double, Int), (String, Double)] { override def createAccumulator() = { ("", 0.0, 0)} override def add(in: (String, Double), acc: (String, Double, Int)) = { (in._1, in lastTemp // update last temperature lastTemp = r.temperature if (prevTemp == 0.0 || r.temperature < prevTemp) { // temperature decreased; delete current timer