• Identified intangible assets consist primarily of purchased technology, backlog, trade names, and customer relationships. Amortization charges for our intangible assets can vary in frequency and amount due to the timing and magnitude of acquisition transactions. We consider our operating results without these charges when evaluating our core performance due to the variability. Generally, the most significant impact to inter-period comparability of our net income (loss) is in the first twelve months following an acquisition.
• Special charges primarily consist of restructuring costs incurred for employee terminations, including severance and benefits, driven by modifications of business strategy or business emphasis. Special charges may also include expenses incurred related to potential acquisitions, excess facility costs, and asset-related charges. Special charges are incurred based on the particular facts and circumstances of acquisition and restructuring decisions and can vary in size and frequency. These charges are excluded as they are not ordinarily included in our annual operating plan and related budget due to the unpredictability of economic trends and the rapidly changing technology and competitive environment in our industry. We therefore exclude them when evaluating our managers' performance internally.
• Equity plan-related compensation expenses represent the fair value of all share-based payments to employees, including grants of employee stock options and restricted stock units. We do not consider equity plan-related compensation expense in evaluating our manager’s performance internally or our core operations in any given period.
• Interest expense attributable to net retirement premiums or discounts on the early retirement of debt, the write-off of associated debt issuance costs and the amortization of the debt discount and premium on convertible debt are excluded. Management does not consider these charges as a part of our core operating performance. The early retirement of debt and the associated debt issuance costs are not included in our annual operating plan and related budget due to unpredictability of market conditions which could facilitate an early retirement of debt. We do not consider the amortization of the debt discount and premium on convertible debt to be a direct cost of operations.
• Equity in earnings or losses of unconsolidated entities represents our equity in the net income (loss) of a common stock investment accounted for under the equity method. The carrying amount of our investment is adjusted for our share of earnings or losses of the investee. The amounts are excluded from our non-GAAP results (with the exception of our investment in Frontline as discussed below) as we do not control the results of operations for this investment and we do not participate in regular and periodic operating activities; therefore, management does not consider these businesses a part of our core operating performance.
• In connection with the Company’s acquisition of Valor on March 18, 2010, we also acquired Valor’s 50% interest in Frontline, a joint venture. We report our equity in the earnings or losses of Frontline within operating income. We actively participate in regular and periodic activities such as budgeting, business planning, marketing and direction of research and development projects. Accordingly, we do not exclude our share of Frontline’s earnings or losses from our non-GAAP results as management considers the joint venture to be core to our operating performance.
• Income tax expense (benefit) is adjusted by the amount of additional tax expense or benefit that we would accrue if we used non-GAAP results instead of GAAP results in the calculation of our tax liability, taking into consideration our long-term tax structure. We use a normalized effective tax rate of 17%, which reflects the weighted average tax rate applicable under the various jurisdictions in which we operate. This non-GAAP tax rate eliminates the effects of non-recurring and period specific items which are often attributable to acquisition decisions and can vary in size and frequency and considers our U.S. loss carryforwards that have not been previously benefited. This rate is subject to change over time for various reasons, including changes in the geographic business mix and changes in statutory tax rates. Our GAAP tax rate for the three months ended April 30, 2012 is 3%, after the consideration of period specific items. Without period specific items of ($1.3) million, our GAAP tax rate is 7%. Our full fiscal year 2013 GAAP tax rate, inclusive of period specific items, is projected to be 7%. The GAAP tax rate considers certain mandatory and other non-scalable tax costs which may adversely or beneficially affect our tax rate depending upon our level of profitability in various jurisdictions.

In certain instances our GAAP results of operations may not be profitable when our corresponding non-GAAP results are profitable or vice versa. The number of shares on which our non-GAAP earnings per share is calculated may therefore differ from the GAAP presentation due to the anti-dilutive effect of stock options and restricted stock units in a loss situation.