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                                                                    EXHIBIT 10.7

     This GUARANTY (this "Guaranty"), dated as of September _, 2003, is made by
Markland Technologies, Inc., a Florida corporation (the "Guarantor"), in favor
of George Yang, a Maryland resident ("Yang")

                                    RECITALS

     WHEREAS, Guarantor, STR Acquisition Corp., a wholly owned subsidiary of
Guarantor ("Merger Sub"), Security Technology, Inc., another wholly owned
subsidiary of Guarantor ("Controlled Subsidiary"), Yang and Security and
Technology Research, Inc., a Maryland corporation all the capital stock of which
is owned by Yang (the "Company") are entering into an Agreement and Plan of
Merger on even date herewith (the "Merger Agreement"), pursuant to which Merger
Sub will merge into the Company and Company will become a wholly owned
subsidiary of Controlled Subsidiary;

     WHEREAS, in consideration for the completion of the transaction as
contemplated in the Merger Agreement, Yang will receive voting common stock of
Guarantor, cash and Merger Sub's promissory note, that by operation of law will
become an obligation of the Company upon the closing of the merger transaction,
in the amount of Three Hundred Seventy-Five Thousand Dollars (the "Note");

     WHEREAS, Yang is willing to enter into the Merger Agreement only if the
Guarantor executes and delivers this Guaranty.

     NOW, THEREFORE, in consideration of the foregoing and of the mutual
covenants contained herein, the parties hereby agree as follows:

     1. GUARANTY. The Guarantor hereby unconditionally and irrevocably
guarantees the full and prompt payment when due of any and all amounts due and
payable under the Note.

     2. OBLIGATIONS PAID IN ACCORDANCE WITH TERMS HEREOF. The Guarantor
guarantees that each payment under the Note shall be paid in accordance with the
terms and provisions thereof without regard to any applicable law now or
hereafter in affect in any jurisdiction that might in any manner affect any of
such terms or provisions or the rights of Yang with respect hereto.

     3. ENFORCEMENT OF GUARANTY. On the date on which the Payment is due and
payable by the Company, Yang, in his sole discretion, may proceed directly
against the Guarantor to exercise any right or remedy that Yang may have under
this Guaranty without pursuing or exhausting any other right or remedy that Yang
may have against the Company.

     4. GUARANTY ABSOLUTE. The obligations of the Guarantor hereunder shall be
absolute and unconditional irrespective of the validity, legality or
enforceability of the Merger Agreement or any event that might otherwise
constitute a legal or equitable discharge of a guarantor, and shall not be
subject to any defense, counterclaim, setoff, recoupment, abatement, reduction
or other determination that the Guarantor, Merger Sub or the Company may have
against Yang, it being agreed that the agreements and liabilities of the
Guarantor hereunder shall not be discharged except by payment or as otherwise
expressly provided in this Guaranty. The Guarantor acknowledges that there are
no conditions precedent to the effectiveness of this Guaranty, and that this
Guaranty is in full force and effect and is binding on the Guarantor as of the
date written above.



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     5. WAIVER. The Guarantor hereby waives notice of acceptance of this
Guaranty and of any action taken or omitted in reliance thereon. The Guarantor
waives any right to require Yang to: (a) proceed against any person, including
Merger Sub or its successor in interest, the Company, (b) proceed against or
exhaust any collateral held from the Company or any other person; (c) pursue any
other remedy in Yang's power; or (d) make any presentments, demands for
performance, or give any notices of nonperformance, protests, notices of
protests or notices of dishonor in connection with any obligations or evidences
of the payments under the Note guaranteed hereunder.

     6. CONTINUING GUARANTY OF PAYMENT. The Guarantor hereby represents and
agrees that this is a present and continuing guaranty of payment and that this
Guaranty (a) shall be binding upon the Guarantor and its respective successors
and assigns and (b) shall inure to and shall be enforceable by Yang and his
successors, transferees and assigns.

     7. REPRESENTATIONS, WARRANTIES AND COVENANTS. The Guarantor hereby
represents, warrants and covenants to Yang that:

          7.1. NO BREACH. The execution and delivery of this Guaranty by the
Guarantor will not result in any breach of or default under any provision of any
contract or agreement of any kind to which the Guarantor is a party or by which
the Guarantor is bound or to which the Guarantor's assets or properties are
subject.

          7.2. DUE AUTHORIZATION; ENFORCEABILITY. The execution of this Guaranty
has been duly authorized by all required action of the Guarantor and this
Guaranty constitutes a valid, legal and binding guaranty of the Guarantor,
enforceable in accordance with its terms.


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     8. MISCELLANEOUS.

          8.1. GOVERNING LAW. This Guaranty is governed by and construed in
accordance with the laws of the State of Maryland, without reference to
principles of conflicts of laws.

          8.2. COSTS, EXPENSES AND ATTORNEYS' FEES. All costs and expenses,
including reasonable attorneys' fees, made or incurred by Yang in the
enforcement of this Guaranty or in the collection of any of the payment under
the Note shall be paid by the Guarantor immediately upon demand.

          8.3. NOTICES. Any notice, request, demand or other communication
permitted or required to be given shall be in writing, shall be signed by the
party giving it, shall be sent to the addressee at the address set forth below
(or at such other address as shall be designated hereunder by notice to the
other parties and persons receiving copies) and shall be deemed conclusively to
have been given (a) when sent by telefax, telex or telegram, (b) on the third
day following the day sent by certified or registered United States mail,
postage prepaid and return receipt requested, or (c) when otherwise delivered to
addressee. The addresses of the parties are as follows:

          (a) If to Yang, at the following address:



          (b) If to Guarantor, at the following address:



          8.4. ENTIRE AGREEMENT. This Guaranty contain all the terms and
conditions of and the entire agreement between Yang and the Guarantor relating
to the subject matter hereof.

          8.5. COUNTERPARTS. This Guaranty may be executed in one or more
counterparts, and by facsimile, each of which may be executed by one or more of
the parties hereto, but all of which, when taken together, shall constitute but
one agreement.

          8.6. NO WAIVER BY ACTION, ETC. Any waiver or consent respecting any
representation, warranty or other provision of this Guaranty shall be effective
only in the specific instance and for the specific purpose for which given and
shall not be deemed, regardless of the frequency given, to be a further or
continuing waiver or consent. The failure or delay of a party at any time or
times to require performance of, or to exercise its rights with respect to, any
representation, warranty or other provision of this Guaranty in no manner
(except as otherwise expressly provided herein) shall affect its right at a
later time to enforce any such provision. No notice to or demand on a party in
any case shall entitle such party to any other or further notice or demand in
this same, similar or other circumstances.


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          8.7. AMENDMENTS. This Guaranty may not be amended, modified, waived or
assigned except by a writing signed by the Guarantor and Yang.

     IN WITNESS WHEREOF, each of the parties hereto has caused this Guaranty to
be executed and delivered as of the date first set forth above.


                                        GUARANTOR:

                                        MARKLAND TECHNOLOGIES, INC.

                                        By: /s/ Ken Ducey
                                            ------------------------------------
                                            Ken Ducey, CFO/President

Approved and Accepted:

George Yang

/s/ George Yang
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