In many industrial sectors, original-equipment manufacturers (OEMs) face a challenging and uncertain future. In recent years, input prices have fallen and growth in emerging markets has slowed, decreasing new-equipment sales in industries ranging from oil and gas to agriculture to commercial aerospace. In response, CEOs at industrial OEMs are increasing their focus on aftermarket services. The appeal of this strategy is simple: services provide stable revenue and often higher margins than sales of new equipment. In this regard,

3.2 With the aid of a diagram, discuss the dependency levels of hierarchical planning highlighting fundamental actions on each horizon. (15)