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                                                                    Exhibit 10.2
                    FIRST AMENDMENT TO OFFICE LEASE AGREEMENT


         THIS FIRST AMENDMENT TO OFFICE LEASE AGREEMENT (this "FIRST AMENDMENT")
is made and entered into this _____ day of ____________, 19____, by and between
BUILDING IV ASSOCIATES L.P. a Virginia limited partnership ("LANDLORD"), and
PERFORMANCE ENGINEERING CORPORATION, a Virginia corporation ("TENANT"), with
reference to the following:

                                    RECITALS

         A. Pursuant to a certain Office Lease Agreement dated May 17, 1999 by
and between Landlord and Tenant (the "LEASE"), Landlord leased to Tenant certain
premises more particularly described therein in the Building commonly known as
Fair Lakes Four, 12700 Fair Lakes Circle, Fairfax, Virginia 22033.

         B. Landlord and Tenant desire to amend the Lease as more particularly
described herein.

         NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which is hereby acknowledged, Landlord and Tenant hereby agree as
follows:

         1. All capitalized terms used herein, unless specifically defined
herein, shall have the same meaning and definition as used in the Lease.

         2. Effective December 1, 1999 (the "FIRST AMENDMENT SPACE COMMENCEMENT
DATE"), pursuant to Tenant's Right of First Offer option set forth in ARTICLE 7
of the Lease, the Premises shall be increased to include 1,947 square feet
located on the first (1st) floor of the Building, more commonly known as Suite
150 (the "FIRST AMENDMENT SPACE"), as more fully described and set forth on
EXHIBIT "A" attached hereto and made a part hereof by this reference. The
expiration date with respect to the First Amendment Space shall be co-terminus
with the Expiration Date of the Lease, which is December 31, 2013 (the "FIRST
AMENDMENT SPACE EXPIRATION DATE"). Landlord and Tenant hereby confirm that
Tenant shall remain in that portion of the Premises presently consisting of
approximately 21,000 square feet of Rentable Area on the second (2nd) floor of
the Building (the "ORIGINAL PREMISES"). From and after the First Amendment Space
Commencement Date, the Premises shall be comprised of the Original Premises and
the First Amendment Space and shall consist of 22,947 square feet of Rentable
Area and Tenant's Proportionate Share shall be 30.58%.

         3. Except as expressly set forth in this First Amendment, Tenant shall
take and lease the First Amendment Space upon the same terms and conditions as
are set forth in the Lease. Notwithstanding anything in the Lease to the
contrary, as to the First Amendment Space: (i) the Commencement Date shall be
the First Amendment Space Commencement Date, (ii) the First Amendment Space
Tenant Improvement Allowance (hereinafter defined) shall be provided in lieu of
the Tenant Improvement Allowance provided in ARTICLE 8 of the Lease; and (iii)
SECTION B.2 of


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EXHIBIT "B" shall not apply. Nothing herein shall accelerate, delay or otherwise
affect the Commencement Date or any other dates as to the Original Premises.

         4. The Base Rent under the Lease shall be increased by adding thereto
the First Amendment Space Base Rent as set forth in this Paragraph 4. Tenant
shall pay to Landlord monthly, in advance, without demand, on the first day of
each calendar month, the monthly Net Base Rent for the First Amendment Space
specified below (the "FIRST AMENDMENT SPACE BASE RENT"), which shall be
increased by the First Amendment Space Tenant Improvement Allowance Rate as
stated in Paragraph 5 of this First Amendment. The First Amendment Space Base
Rent shall be calculated on the first day of each Lease Year under the Lease by
multiplying the Base Rent per Square Foot (as hereinafter defined) by the
Rentable Area of the First Amendment Space. The first monthly installment of
First Amendment Space Base Rent shall be payable in advance on the First
Amendment Space Commencement Date.

                                                    FIRST AMENDMENT SPACE

                                  Base Rent
                                Per Square Foot             Net Base Rent
    LEASE YEAR              (INCLUDES 3% COMMISSION)       PER SQUARE FOOT
     ----------             ------------------------      ---------------
       1                           $15.41                       $14.52
       2                           $15.95                       $15.06
       3                           $16.51                       $15.62
       4                           $17.09                       $16.20
       5                           $17.68                       $16.79
       6                           $18.30                       $17.41
       7                           $18.95                       $18.06
       8                           $19.61                       $18.72
       9                           $20.30                       $19.41
      10                           $21.01                       $20.12
      11                           $21.74                       $20.85
      12                           $22.50                       $21.61
      13                           $23.29                       $22.40
      14                           $24.11                       $23.22

         For purposes hereof, "Lease Year 1" or the first "Lease Year" shall
mean the period commencing on the First Amendment Space Commencement Date and
terminating on December 31, 2000. All other references to "Lease Year" shall
mean a period of twelve (12) consecutive months commencing on January 1, 2001,
and each successive twelve (12) month period thereafter and shall coincide with
the Lease Year for the Original Premises.

         5. Tenant agrees to accept the First Amendment Space in its "as is" and
"where is" condition, and Landlord will have no obligation to make any
improvements or modifications to the First Amendment Space and Landlord shall
have no obligation to make any alterations or improvements to the First
Amendment Space. If Tenant elects to use the First Amendment Space Tenant
Improvement Allowance, Landlord shall not be obligated to complete alterations


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or improvements prior to the First Amendment Space Commencement Date.
Notwithstanding the foregoing, provided that Tenant does not default under the
Lease, Landlord shall provide Tenant with an allowance (the "FIRST AMENDMENT
SPACE TENANT IMPROVEMENT ALLOWANCE") for the construction of leasehold
improvements to the First Amendment Space of up to $8.00 per square foot of
Rentable Area comprising the First Amendment Space, but in no event to exceed
$15,576.00. The First Amendment Space Tenant Improvement Allowance shall be
applied by Landlord to the costs to be borne by Tenant pursuant to EXHIBIT "B"
to the Lease. Tenant shall reimburse Landlord for all amounts paid by Landlord
to Tenant from the First Amendment Space Tenant Improvement Allowance on a
monthly basis with Tenant's payment of Base Rent in an amount equal to the First
Amendment Space Tenant Improvement Allowance Rate. The First Amendment Space
Tenant Improvement Allowance Rate shall mean the First Amendment Space Tenant
Improvement Allowance provided by Landlord to Tenant amortized over the
remaining Term at an interest rate of nine and one-half percent (9 1/2%) per
annum. The First Amendment Space Tenant Improvement Allowance Rate shall be
added to and constitute part of the First Amendment Space Base Rent.

         6. From and after the First Amendment Space Commencement Date, Tenant
shall pay the Tenant's Proportionate Share of Operating Expenses and Real Estate
Taxes with respect to the First Amendment Space in accordance with PART 4 of the
Lease.

         7. By no later than December 31, 1999, Tenant shall deliver to Landlord
an additional Security Deposit of $5,005.55, subject to increase in accordance
with PARAGRAPH 1(b)(vii) OF EXHIBIT "E" OF THE LEASE. The last sentence of
SECTION 23.04 of the General Lease Provisions is hereby amended by replacing
"$84,875.00" with "$89,875.55."

         8. In the event that prior to occupancy of the First Amendment Space
Tenant performs alterations to the First Amendment Space that require building
or other permits, and provided that Tenant does not default under the Lease,
then Landlord agrees that the Base Rent for the First Amendment Space shall
abate for one-half (1/2) of the total days that Landlord and Tenant reasonably
anticipate will be required to construct such alterations (excluding Tenant
Delay), not to exceed forty-five (45) days of rental abatement.

         9. Except as expressly modified by this First Amendment, the Lease
remains unchanged and in full force and effect. In the event of a conflict
between the provisions of this First Amendment and the Lease, this First
Amendment shall prevail. This First Amendment sets forth entire agreement
between the parties and cancels all prior negotiations, arrangements, brochures,
agreements, and understandings, if any, between Landlord and Tenant regarding
the subject matter of this First Amendment. No amendment or modification of this
First Amendment shall be binding or valid unless expressed in a writing executed
by both parties hereto.


                        [SIGNATURES FOLLOW ON NEXT PAGE.]




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         IN WITNESS WHEREOF, Landlord and Tenant have executed this First
Amendment as of the day and year first above written.

                                            LANDLORD:

                                            BUILDING IV ASSOCIATES L.P.
                                            a Virginia limited partnership

                                            By:     Building IV Associates, Inc.
                                                    a Virginia corporation
                                                    its general partner

                                            By:
                                                     ---------------------------
                                            Name:
                                                     ---------------------------
                                            Its:
                                                     ---------------------------

                                            TENANT:

                                            PERFORMANCE ENGINEERING CORPORATION
                                            a Virginia corporation

                                            By:
                                                     ---------------------------
                                            Name:
                                                     ---------------------------
                                            Its:
                                                     ---------------------------




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                                   EXHIBIT "A"


                       FLOOR PLAN OF FIRST AMENDMENT SPACE


                                [TO BE ATTACHED.]


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