Question

please explain the cost model and the revaluation model of measurement subsequent to initial recognition.

This is from Fixed Assets chapter.

Answer 1

Cost model: The asset is carried at cost less accumulated depreciation and impairment.  

Revaluation model. The asset is carried at a revalued amount, being its fair value at the date of revaluation less subsequent depreciation and impairment, provided that fair value can be measured reliably.
The revaluation model

Under the revaluation model, revaluations should be carried out regularly, so that the carrying amount of an asset does not differ materially from its fair value at the balance sheet date.

If an item is revalued, the entire class of assets to which that asset belongs should be revalued. [

Revalued assets are depreciated in the same way as under the cost model (see below).

If a revaluation results in an increase in value, it should be credited to other comprehensive income and accumulated in equity under the heading "revaluation surplus" unless it represents the reversal of a revaluation decrease of the same asset previously recognised as an expense, in which case it should be recognised in profit or loss.

A decrease arising as a result of a revaluation should be recognised as an expense to the extent that it exceeds any amount previously credited to the revaluation surplus relating to the same asset.

When a revalued asset is disposed of, any revaluation surplus may be transferred directly to retained earnings, or it may be left in equity under the heading revaluation surplus. The transfer to retained earnings should not be made through profit or loss.