REVOLVING NOTE

Exhibit 4.4

IMPORTANT NOTICE

THIS INSTRUMENT CONTAINS A CONFESSION OF JUDGMENT PROVISION WHICH CONSTITUTES A WAIVER OF IMPORTANT RIGHTS YOU MAY HAVE AS A DEBTOR AND ALLOWS THE CREDITOR TO OBTAIN A JUDGMENT AGAINST YOU WITHOUT ANY FURTHER NOTICE.

REVOLVING NOTE

     FOR VALUE RECEIVED, Horne Engineering Services, LLC, and Spectrum Sciences & Software Holdings Corp. (jointly and severally, the “Borrower”), both having an address at c/o Horne Engineering Services, LLC, 3130 Fairview Park Drive, Suite 400, Falls Church, Virginia 22042, promise to pay to the order of Bank of America, N.A., a national banking association (the “Lender”), the principal sum of Six Million and 00/100 Dollars ($6,000,000.00) (the “Principal Sum”), or so much thereof as has been or may be advanced or readvanced to or for the account of the Borrower pursuant to the terms and conditions of the Loan Agreement (as hereinafter defined), together with interest thereon at the rate or rates hereinafter provided, in accordance with the following terms:

1. Interest .

     a. Commencing as of the date hereof and continuing thereafter, the unpaid Principal Sum shall bear interest at a fluctuating annual rate equal to the LIBOR Rate (as hereafter defined), plus Two and One Half of a percent (2.50%). The “LIBOR Rate” means the interest rate determined by the following formula, rounded upward to the nearest 1/100 of one percent.

“London Inter-Bank Offered Rate” means the average per annum interest rate at which U.S. dollar deposits would be offered for an “Interest Period” of one (1) month by major banks in the London inter-bank market, as shown on the Telerate Page 3750 (or any successor page) at approximately 11:00 a.m. London time two (2) London Banking Days before the commencement of the Interest Period. If such rate does not appear on the Telerate Page 3750 (or any successor page), the rate for that Interest Period will be determined by such alternate method as reasonably selected by Lender. A “London Banking Day” is a day on which Lender’s London Banking Center is open for business and dealing in offshore dollars. “Reserve Percentage” means the total of the maximum reserve percentages for determining the reserves to be maintained by member banks of the Federal Reserve System for Eurocurrency Liabilities, as defined in Federal

Reserve Board Regulation D, rounded upward to the nearest 1/100 of one percent. The percentage will be expressed as a decimal, and will include, but not be limited to, marginal, emergency, supplemental, special, and other reserve percentages. The first day of the Interest Period must be a day other than a Saturday, or a Sunday on which Lender is open for business in New York and London and dealing in offshore dollars (a “LIBOR Banking Day”). The last day of the Interest Period and the actual number of days during the Interest Period will be determined by Lender using the practices of the London inter-bank market. Absent manifest error, the Lender’s certificate to the Borrower stating the LIBOR Rate for each Interest Period shall be conclusive.

     The rate at which interest shall accrue under this Note may change immediately upon any change at the commencement of each Interest Period (if the London Inter-Bank Offered Rate has changed).

     All interest payable under the terms of this Note shall be calculated by applying a daily interest rate, determined by multiplying the outstanding principal balance by the applicable annual interest rate and dividing the resulting product by 360, to the actual number of days principal is outstanding.

2. Payments and Maturity . The unpaid Principal Sum, together with interest thereon at the rate or rates provided above, shall be payable as follows:

     a. interest shall be due and payable monthly, commencing on the first day of the first calendar month after the date of this Note, and on the first day of each succeeding calendar month.

     b. unless sooner paid, the unpaid Principal Sum, together with all interest accrued and unpaid thereon, and all other amounts owing under this Note shall be due and payable in full on April 30, 2007 (the “Maturity Date”). If the Loan Agreement provides for the Borrower to make additional payments on account of the Principal Sum from time to time, Borrower promises to make those payments at the time and in the manner specified in the Loan Agreement.

3. Default Interest . Upon the occurrence of an Event of Default (as hereinafter defined), the unpaid Principal Sum shall bear interest thereafter, until the Event of Default is cured, at a rate of two percent (2%) per annum in excess of the rate or rates of interest that would otherwise be in effect under this Note.

4. Late Charges . If the Borrower fails to make any payment under the terms of this Note within ten (10) days after the date such payment is due, the Borrower shall pay to the Lender on demand a late charge equal to five percent (5%) of such payment.

5. Application and Place of Payments . Except as otherwise provided in the Loan Agreement (hereinafter defined), all payments, made on account of this Note shall be applied

first to the payment of accrued and unpaid interest then due hereunder, second to the unpaid principal balance and the remainder, if any, shall be applied to any other amounts which remain owing hereunder. All payments on account of this Note shall be paid in lawful money of the United States of America in immediately available funds