+--------+
| FORM 3 |          U.S. SECURITIES AND EXCHANGE COMMISSION
+--------+                  WASHINGTON, D.C. 20549
          
            INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

    Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934,
      Section 17(a) of the Public Utility Holding Company Act of 1935 or
              Section 30(f) of the Investment Company Act of 1940

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1.  Name and Address of Reporting Person

       Kotowski                     Andreas                           F.
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        (Last)                      (First)                        (Middle)

                             12525 Chadron Avenue
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                                   (Street)

       Hawthorne                   California                          90250
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        (City)                      (State)                           (Zip)


2.  Date of Event Requiring Statement (Month/Day/Year)                10/1/97
                                                                  --------------

3.  IRS or Social Security Number of Reporting Person (Voluntary)   000-00-0000
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4.  Issuer Name and Ticker or Trading Symbol  OSIS
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5.  Relationship of Reporting Person to Issuer (Check all applicable)

    [ ] Director    [X] Officer             [ ] 10% Owner    [ ] Other
                        (give title below)                       (specify below)

    President of U.S. Operations, Rapiscan U.S.A.
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6.  If Amendment, Date of Original (Month/Day/Year) 
                                                    ----------------------------


             TABLE I--NON-DERIVATIVE SECURITIES BENEFICIALLY OWNED

- -------------------------------------------------------------------------------- 1. Title 2. Amount of 3. Ownership Form: 4. Nature of of Securities Bene- Direct (D) or Indirect Bene- Security ficially Owned Indirect (I) ficial Ownership (Instr. 4) (Instr. 4) (Instr. 5) (Instr. 5) - -------------------------------------------------------------------------------- Common Stock, no par value 128,806* D - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - --------------------------------------------------------------------------------
*Includes 7,500 shares issuable pursuant to fully vested options. Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. (Print or Type Responses) FORM 3 (continued) TABLE II--DERIVATIVE SECURITIES BENEFICIALLY OWNED (e.g., puts, calls, warrants, options, convertible securities)
- ------------------------------------------------------------------------------------------------------------------------------------ 1. Title of Derivative 2. Date Exer- 3. Title and Amount of Securities 4. Conversion 5. Ownership 6. Nature of In- Security (Instr. 4) cisable and Underlying Derivative Security or Form of direct Bene- Expiration (Instr. 4) Exercise Derivative ficial Date Price Security: Ownership (Month/Day/ of Direct (D) (Instr. 5) Year) Derivative or In- ---------------------------------------------------- Security direct (I) Date Expira- Amount or (Instr. 5) Exer- tion Title Number of cisable Date Shares - ------------------------------------------------------------------------------------------------------------------------------------ Options to Purchase * 11/14/01 Common Stock 7,500 $ 2.83 D Common Stock - ------------------------------------------------------------------------------------------------------------------------------------ Options to Purchase ** 5/31/02 Common Stock 20,000 $11.50 D Common Stock - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - -----------------------------------------------------------------------------------------------------------------------------------
Explanation of Responses: *Fully vested **Vest over a four-year period from date of grant. ***Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a). Note: File three copies of this Form, one of which must be manually signed. If space provided is insufficient, See Instruction 6 for procedure. /s/ Andreas F. Kotowski 9/30/97 ------------------------------- ----------------- **Signature of Reporting Person Date By: For: