Intangible Assets Intangible assets mainly included 3G Concession, computer software, patents and goodwill. The 3G Concession is valid through December 31, 2018. The 3G Concession fee is amortized on a straight-line basis from the  date operations commence through the date the license expires. Computer software costs and patents are amortized using the  straight-line method over the estimated useful lives of 2 to 20 years. When an indication of impairment is identified for intangible assets other than goodwill, any excess of the carrying amount of  an asset over its recoverable amount is recognized as a loss. If the recoverable amount increases in a subsequent period, the  amount previously recognized as impairment would be reversed and recognized as a gain. However, the adjusted amount may  not exceed the carrying amount that would have been determined, as if no impairment loss had been recognized. Goodwill represents the excess of the consideration paid for business acquisition over the fair value of identifiable net assets  acquired. Goodwill is tested for impairment annually. If an event occurs or circumstances change which indicates that the fair  value of goodwill is below its carrying amount, an impairment loss is recognized. A subsequent reversal of such impairment  loss is not allowed. Idle assets are carried at the lower of recoverable amount or carrying amount. Idle Assets Pension Costs For defined benefit pension plans, net periodic pension benefit cost is recorded in the consolidated statement of income and  includes service cost, interest cost, expected return on plan assets, amortization of prior service costs, amortization of pension  gains (losses) and curtailment or settlement gains (losses).  The Company recognizes into income, any unrecognized actuarial net gains or losses that exceed 10% of the larger of projected  benefit obligations or plan assets, defined as the “corridor”. Amounts inside this 10% corridor are amortized over the average  remaining service life of active plan participants. Actuarial net gains and losses occur when actual experience differs from  any of the many assumptions used to value the plans. Differences between the expected and actual returns on plan assets and  changes in interest rate, which affect the discount rate used to value projected plan obligations, can have a significant impact on  the calculation of pension net gains and losses from year to year.  Curtailment/settlement gains or losses are equal to the changes of underfunded status plus the a pro rata portion of the  unrecognized prior service cost, unrecognized net gains (losses), and unrecognized transition obligations/assets, before the  settlement/curtailment event multiplied by the percentage reduction in projected benefit obligation.  The projected benefit obligation represents the actuarial present value of benefits expected to be paid upon retirement based on  estimated future compensation levels.  The carrying amount of accrued pension liability should be the sum of the following amounts when the calculation is  positive: (a) projected benefit obligation as of balance sheet date, (b) minus (plus) unamortized actuarial loss (gain), (c) minus  unamortized prior service cost, and (d) minus the fair value of plan assets. If the amount determined by above calculation  is negative, it is viewed as prepaid pension cost. The prepaid pension cost is measured at the lower of: (a) the amount  determined above, and (b) the sum of the following amounts: (i) unamortized actuarial loss, (ii) unamortized prior service cost,  and (iii) the present value of refunds from the plan or reductions in future contributions to the plan. F-20 PART III