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                                                                   EXHIBIT 10.47

                     MUTUAL COMMITMENT TO BUILD AND TO LEASE

        This  Mutual Commitment to Build and to Sub-Lease  is executed this  5th
day  of June, 1998, between Engineering Development Laboratories, Inc. (EDL), an
Ohio  for  profit  corporation; UES, Inc. (UES), an Ohio for profit corporation;
and  Beavercreek  Enterprises  (Beavercreek),  an  Ohio general partnership. The
parties covenants and agree as follows:

        1. Beavercreek  is the owner of certain premises located at 4401 Dayton-
           Xenia Road, Beavercreek, Ohio.

        2. UES  leases  said   premises   from   Beavercreek,   and   sub-leases
           approximately  9,350  square feet of said premises to EDL, identified
           as a portion of Building No. 3.

        3. EDL  desires  an  additional  approximately  4,000 square feet leased
           space.  Beavercreek  agrees to construct certain additions to provide
           said  additional  space,  and  UES agrees to lease said addition from
           Beavercreek and to sub-lease 6,800 square feet to EDL.

        4. To effectuate  the  foregoing, the following agreements are agreed to
           and ratified:

           a. Beavercreek  will  construct  an  addition of approximately 13,600
              square feet  to  Building No. 3 for partial use by EDL (per agreed
              to specifications of EDL and STL).

           b. EDL  will  continue  their  current sub-lease with UES, and hereby
              ratifies and confirms the existing sub-lease.

           c. At the  time  EDL takes occupancy of the new addition, the present
              lease  by  UES,  and  sub-lease  by  EDL,  shall  terminate and be
              replaced  by  a  new lease which shall include approximately 6,532
              square  feet of the present space, plus approximately 6,800 square
              feet of the new addition, or 13,332 square feet in total.

           d. The terms  and conditions of the present lease and sub-lease shall
              be  incorporated  in the new lease and sub-lease; if janitorial is
              added the lease rate will be increased by $.50/sq. ft.

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           e. If the merger of Paravant,  STL and  EDL  does not take place, EDL
              will  be  committed  to  year  one  of the agreement. Year two and
              following will be renegotiated.

        The new  lease will  be for five  years with an option for an additional
three  years  at a  2% escalation. The lease rate for the first five years is as
follows:

<TABLE>
<CAPTION>
               Year           $/Month
               ----           -------
              <S>               <C>    
               1              $10,938

               2              $12,665

               3              $14,449

               4              $14,738

               5              $15,032
</TABLE>


                                   Engineering Development Laboratories, Inc.
                                   (EDL)

                                    --------------------------------------------
                                    By /s/James Clifford
                                       James Clifford, its President

                                    UES, Inc.

                                    --------------------------------------------
                                    By /s/Krishan K. Joshi
                                       Krishan K. Joshi, its President

                                    Beavercreek Enterprises

                                    --------------------------------------------
                                    By /s/Krishan K. Joshi
                                       Krishan K. Joshi, General Partner



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