Document:

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                                                                   Exhibit 10.15

       ADDENDUM NO. 1 TO AGREEMENT REGARDING INTELLECTUAL PROPERTY RIGHTS

by and between:

         Gunnar Foss, a Norwegian citizen resident in Mezenplei 11, 2566 Z6, den
         Haag, The Netherlands (hereinafter referred to as Foss); and Per Bull
         Haugsoen, a Norwegian citizen, residing at Risalleen 53, 0377 Oslo
         (hereinafter referred to as Haugsoen)

on the one hand,

and

         Marine Shuttle Operations AS, a Norwegian Company having its registered
         office at Lyramyrveien 29, 4301 Sandnes; and Marine Shuttle Operations
         Inc, a company organized and existing under the laws of Nevada, USA,
         having its principle place of business at 4410 Monterose Boulevard,
         Houston, Texas 77006, USA; (hereinafter jointly and individually
         referred to as MSO)

the following Addendum No. 1 to The Agreement Regarding Intellectual Property
has today been entered into:

1.       Background

1.1      On March 31, 1998, Foss and Haugsoen entered into an Agreement
         Regarding Intellectual Property (the "Original Agreement") with
         Offshore Shuttle AS (hereinafter referred to as OSAS). Under the
         Original Agreement, which is enclosed herewith as Exhibit 1, Foss and
         Haugsoen transferred to OSAS all Rights (as defined in the Original
         Agreement) pertaining to the Offshore Shuttle Concept, subject to the
         conditions and qualifications contained in the Original Agreement.

1.2      Subsequent to the execution of the Original Agreement, OSAS (and its
         successor by merger, MSO) has actively pursued the further development
         of the Offshore Shuttle Concept as contemplated by the Original
         Agreement.

1.3      During the Winter and Spring of 1999, the development of the Offshore
         Shuttle concept has reached a level where detailed negotiations for
         award of contracts for the design, construction and fabrication of the
         first Offshore Shuttle are ongoing in parallel with negotiations with
         credit institutions for procurement of the corresponding finance
         facility.

2.       Waiver of Rights - Transfer of Rights under Patent Applications

         Subject to the fulfilment of the conditions contained in Article 3
         hereof, Foss and Haugsoen agree, individually and collectively, to
         forever waive and relinquish any and all rights to have the Rights
         transferred back to them, individually or collectively, in accordance
         with Article 2, 2nd paragraph of the Original Agreement.

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         Foss and Haugsoen further agree, individually and collectively, to
         forever waive and relinquish any and all rights of first refusal in the
         event of assignment of the said Rights to any Third Party as provided
         in Article 5 of the Original Agreement.

         Except as provided for in Article 3 of this Addendum, the waiver of
         rights as contained in the foregoing paragraphs hereof is irrevocable
         and unconditional and shall be contingent upon no other circumstance or
         condition.

         Upon completion of those conditions as specified in Article 3 hereof,
         Foss and Haugsoen undertake, individually and collectively, to execute
         any such document(s) which may be requisite or proper in order to more
         effectively waive and relinquish the Rights, such that all rights to
         the Offshore Shuttle Concept are vested in MSO.

3.       Conditions Precedent

         The waiver of rights as contained in Article 2 hereof shall only become
         effective upon satisfaction of the following conditions:

         o   The receipt by MSO, or any company or entity controlled directly or
             indirectly by MSO, of a written commitment for a financing (debt,
             equity or other) for the full and complete design and fabrication
             of the first Offshore Shuttle.

         o   The entering into by MSO, or any company or entity controlled
             directly or indirectly by MSO, of such contracts as are required
             for the design, construction and complete fabrication of the first
             Offshore Shuttle.

         o   Completion of the Stock Exchange Agreements referred to below under
             Article 5.1 of this Addendum No. 1.

         The conditions in this Article 3 shall all be fulfilled within 24
         months from the execution of this Addendum No. 1, or otherwise this
         Addendum No. 1 shall be null and void.

4.       Consideration

         In consideration of the waiver of the Rights as provided herein MSO
         shall grant to each of Foss and Haugsoen warrants to purchase 125,000
         (one hundred and twenty five thousand) shares of common stock of Marine
         Shuttle Operations Inc at value 1 - one - U.S. Dollar per share. Such
         Warrants are enclosed herewith as Exhibits 2 and 3, respective, and
         shall be granted immediately only upon satisfaction of the conditions
         defined in Article 3 hereof.

5.       Various

5.1      The parties agree that the Stock Exchange Agreements entered into in
         April, 1998 between Marine Shuttle Operations Inc. and respectively
         Foss and Haugsoen shall be closed without any undue delay. In this
         respect, Marine Shuttle Operations Inc. undertakes to take such
         actions, hereunder submitting the appropriate letter of

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         instructions to the Transfer Agent as to the names in which the share
         certificates should be registered and where the certificates should be
         sent. Additionally, Marine Shuttle Operations Inc. will cause a legal
         opinion by counsel to be submitted to the Transfer Agent regarding the
         issuance of the shares under applicable securities laws. Such actions
         shall be taken by Marine Shuttle Operations Inc. no later than 10 days
         following the execution of this Addendum No. 1, and Marine Shuttle
         Operations Inc. further undertakes to use its best effort to insure the
         diligent and timely completion of the stock exchange.

5.2      Foss and Haugsoen each agree that in connection with any future
         underwritten public or private offering of Marine Shuttle Operations
         Inc. common stock, upon request of Marine Shuttle Operations Inc. or
         the principal underwriter managing such public offering, the shares of
         common stock of Marine Shuttle Operations Inc. then held by each of
         them may not be sold, offered for sale, or otherwise disposed of
         without the prior written consent of Marine Shuttle Operations Inc. or
         such underwriter, as the case may be, for a specific period, at least
         90 days after the effectiveness of the registration statement filed in
         connection with such offering (or such longer period of time as the
         Marine Shuttle Operations Inc. Board of Directors may determine),
         provided that all of the Company's executive officers (inclusive of
         Directors and leading personnel) of Marine Shuttle Operations Inc. and
         Marine Shuttle Operations AS, agree to be similarly bound. The
         obligations under this Section shall remain effective for five (5)
         years after the date hereof.

5.3      The parties agrees that this Addendum No. 1 shall be interpreted and
         construed in accordance with the laws of The Kingdom of Norway.

                                       ***

This Addendum No. 1 has been executed in 4 - four - counterparts; one to each of
the parties and one to Marine Shuttle Operations Inc.

                        Oslo, Norway this ________ , 2000

                                            Marine Shuttle Operations Inc.

---------------------------                 -------------------------------
Per Bull Haugsoen

                                            Marine Shuttle Operations AS

--------------------------                  -------------------------------
Gunnar Foss

Enclosures

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                                                                 Execution Copy
                               OPERATING AGREEMENT

         THIS OPERATING AGREEMENT ("Agreement") is made and entered into
effective February 1, 2000 (the "Effective Date"), by Acxiom Corporation
("Acxiom"), a Delaware corporation, and Sedona Corporation ("Sedona"), a
Pennsylvania corporation.

                                    RECITALS

         WHEREAS, Acxiom and Sedona entered into a Letter of Intent dated
January 11, 2000 and are negotiating and finalizing the definitive Asset
Purchase and Sale Agreement (the "Asset Purchase Agreement"), pursuant to which
Acxiom has agreed to sell, and Sedona has agreed to purchase substantially all
the assets of Acxiom's business unit located in Minneapolis, Minnesota, which
utilizes the assets in designing and implementing Customer Information
Management Systems (the "Business");

         WHEREAS, Sedona has effectively assumed the operations of the Business
as of February 1, 2000;

         WHEREAS, during the continued negotiations of the Asset Purchase
Agreement and finalization thereof, Sedona has assumed the responsibilities and
risk of loss for the Business.

         NOW THEREFORE, in exchange for the mutual promises, covenants and
Agreements contained herein, the parties hereto, intending to be legally bound,
agree as follows:

         1. Delegation and Assumption of Responsibilities. Acxiom hereby
delegates all responsibilities to Sedona to operate the Business, and Sedona
hereby assumes all responsibilities from Acxiom to operate the Business during
the term of this Agreement.

         2. Operating Agreement Fee. For all the rights and powers granted to
Sedona under this Agreement and commencing as of the Effective Date, Acxiom
shall share with Sedona ninety-five percent (95%) of any net profit or net loss
of the Business. "Net profit" or "net loss" are defined as net billings less all
costs and expenses incurred in the Business consistent with past practices, for
each month Sedona operates the Business.

         Acxiom shall continue to collect all Business accounts receivable and
pay all Business payables during the term of this Agreement. Sedona shall not be
responsible for expenses resulting from problems arising out of existing
software configuration which is being acquired as part of the Asset Purchase
Agreement and referred to as Customer Information Management Systems ("CIMS").

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         3. Invoicing Procedures. By the 10th of each month, (a) Sedona shall
invoice to Acxiom an amount equal to the gross billings for the previous month
and (b) Acxiom shall invoice Sedona for the expenses incurred in the operating
of the Business for the previous month and further reflect on such invoice the
amount due from Sedona or the amount due to Sedona for the Net Profit or Net
Loss for the same month. The parties agree to share information with one another
as may be reasonably necessary in order to properly prepare each parties'
respective invoice. Furthermore, each party agrees to allow the other party
reasonable access to review and examine accounting records that may be used to
support invoices pursuant to this agreement. Expenses attributed to the Business
shall not include any corporate overhead or other allocations which are not
directly attributable to Business. Acxiom designates Jeff Stalnaker, and Sedona
designates Bill Williams to coordinate and resolve any issues regarding the
above calculation.

         4. Responsibility for Cost and Expenses. During the term of this
Agreement, Sedona will bear responsibility for (i) all operating costs to
maintain the Business; (ii) the cost of leasing any space for the Business;
(iii) all personnel necessary for operation of the business unit and will be
responsible for the salaries, taxes, insurance and related costs for all such
personnel; (iv) property and casualty insurance for the business as hereinafter
provided; (v) maintenance of the facilities and any cost related to the
replacement of any equipment necessary to carry out the intent of this
Agreement; and (iv) all other costs consistent with Acxiom's past operation of
the Business, provided that all costs shall be recorded in accordance with
generally accepted accounting principles ("GAAP"). For purposes hereof, Acxiom
agrees that the costs of the Business shall not include any corporate overhead
or other allocated costs which are not directly attributable to the Business.

         5. Sedona's Insurance. At all times while this Agreement remains in
effect, Sedona shall maintain liability insurance with coverage of at least
$1,000,000 per occurrence, workers compensation insurance and commercial general
liability insurance with a combined single limit of $3,000,000 with insurance
companies that have a Best rating of A- or better. Sedona shall deliver
certificates of insurance periodically to Acxiom evidencing that such insurance
remains in effect and such policies shall name Acxiom as an additional insured.

         6. Term. The term of this Agreement shall commence on the Effective
Date and continue for a period of four (4) months unless terminated sooner as
provided for herein. Notwithstanding the foregoing, this Agreement shall
terminate upon the earlier of (i) the failure of the parties to execute and
deliver the Asset Purchase Agreement not later than March 20, 2000; (ii) the
closing of the Asset Purchase Agreement; (iii) the termination of the Asset
Purchase Agreement pursuant to the terms of the Asset Purchase Agreement; or(iv)
termination pursuant to Section 10 of this Agreement.

         7. Trade Creditors. Sedona and Acxiom shall pay their respective trade
creditors in a timely fashion consistent with good business practices.

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         8. Operation of Business. Sedona shall have full authority and power
over the operation of the Business during the term of this Agreement, including
but not limited to hiring and firing employees, hiring and firing sales
associates and all other aspects of the Business. At all times during the term,
all personnel shall be subject to the supervision and the direction of Sedona's
manager or supervisors. Sedona shall comply with all laws, regulations and the
like in discharging its operational authority hereunder, and it shall notify
Acxiom of any material adverse changes to the Business or any other material
events relating thereto which may happen during the Term of this Agreement.

         9. Events of Default. The following shall, after expiration of the
applicable cure periods, constitute events of default under this Agreement:

            (a) Failure for Sedona to run the Business consistent with past
practices;

            (b) Failure for Sedona to reimburse Acxiom for any undisputed loss
pursuant to Paragraph 2; or

            (c) Any other material breach of the spirit and intent or warrants
of this Agreement.

         10. Cure Periods. An Event of Default shall not be deemed to have
occurred until fifteen (15) days (or in the event of payment default, five (5)
days) after the non-defaulting party has provided the defaulting party with
written notice specifying the event or events that if not cured would constitute
an Event of Default and specifying the actions necessary to cure within such
period. This period shall be extended for a reasonable period of time if the
defaulting party is acting in good faith to cure and such delays are not
materially adverse to the non-defaulting party.

         11. Termination. In the event of an occurrence of an Event of Default,
the non-defaulting party may terminate this Agreement provided that such party
is not then also in default. Upon termination, Sedona's operational rights
granted hereunder should terminate and full control of the Business shall revert
to Acxiom. Within twenty (20) days of any termination, Acxiom shall prepare and
deliver a final accounting of all activity hereunder and invoices resulting
therefrom shall be immediately paid.

         12. Indemnification Rights. Each party will indemnify and hold harmless
the other party, and the directors, officers, partners, employees, agents and
affiliates of such other party from and against any and all liability, including
without limitation reasonable attorney's fees arising out of or incident to (i)
any breach by such party of a representation, warranty or covenant made herein;
and (ii) the conduct of such party, its employees, contractors and agents
(including negligence) in performing its obligations hereunder. Without limiting
the generality of the foregoing, each party will indemnify and hold harmless the
other party, and the directors, officers, partners, employees, agents and
affiliates of such other party, from and against all liability arising out of
its actions under this Agreement except to the extent that such liability or
loss arises under the general operations and is accounted for pursuant to
hereof. The parties indemnification obligations hereunder shall survive any
termination or expiration of this Agreement for a period of one (1) year.

            13. Representations. Both Acxiom and Sedona hereby represent that
they are legally qualified, empowered, and authorized to execute this Agreement
and carry out the activities contemplated hereby.

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         14. Public Announcement. Neither party shall make any further public
announcements without first having obtained written approval of the other party.

         15. Miscellaneous.

              (a) Assignment. This agreement and the rights, obligations and
duties of the Acxiom shall not be assignable or otherwise transferable unless
agreed to in writing by both parties.

              (b) Modification. No term or provision contained herein may be
modified, amended or waived except by written agreement signed by the party to
be bound thereby.

                  (c) Binding Effect and Benefit. This agreement shall inure to
the benefit of, and shall be binding upon, the parties hereto, and their
respective heirs, executors, administrators, personal representatives,
successors and permitted assigns.

              (d) Headings and Captions. Subject headings and captions are
included for convenience purposes only and shall not affect the interpretation
of this agreement.

              (e) Notice. All notices, requests, demands and other
communications permitted or required hereunder shall be in writing, and either
(i) delivered in person, (ii) sent by express mail or other overnight delivery
service providing receipt of delivery, (iii) mailed by certified or registered
mail, postage prepaid, return receipt requested or (iv) sent by facsimile
transmission as follows:

                  If to the Seller, addressed or delivered in person to:

                  Acxiom Corporation
                  #1 Information Way
                  Little Rock, AR 72202
                  Attn: General Counsel
                  Telecopy No.: (501) 252-5610

                  With copy to:

                  Friday Eldredge & Clark
                  400 W. Capitol, Suite 2000
                  Little Rock, AR 72201
                  Attn: Carla G. Spainhour, Esq.
                  Telecopy No.: (501) 376-2147

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                  If to Buyer, addressed or delivered in person to:

                  Sedona Corporation
                  649 North Lewis Rd.
                  Limerick, PA 19468
                  Attn: Marco Emrich, President & CEO
                  Telecopy No.: (610) 495-3092

          With copy to:

                  Dale Goodfriend, Esq.
                  617 Southwest 9th Ave.
                  Rochester, MN 55902
                  Telecopy No.: (507) 281-3672

or to such other address as either party may designate by notice in the manner
provided above.

         Any such notice or communication, if properly given or made by prepaid,
registered or certified mail or by recorded express delivery, shall be deemed to
have been made when actually received, but not later than three (3) business
days after the same was posted or given to such express delivery service, and if
made properly facsimile transmission such notice or communication shall be
deemed to have been made at the time of dispatch and receipt of proof of
transmission.

         IN WITNESS WHEREOF, the parties have executed this Agreement as of the
date first written above.

                              ACXIOM CORPORATION

                              -----------------------------------
                              Jeff D. Stalnaker, Finance and Accounting Leader,
                              Financial Services Division

                              SEDONA CORPORATION

                              ----------------------------------
                              Marco Emrich, President & CEO

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