EXHIBIT 3.31

                          CERTIFICATE OF INCORPORATION

                                       OF

                         LINEAL ACQUISITION CORPORATION

            1. The name of this corporation is Lineal Acquisition Corporation.

            2. The registered office of this corporation in the State of
Delaware is located at 1013 Centre Road, in the City of Wilmington, County of
New Castle. The name of its registered agent at such address is Corporation
Service Company.

            3. The purpose of this corporation is to engage in any lawful act or
activity for which corporations may be organized under the General Corporation
Law of the State of Delaware.

            4. The total number of shares of stock that this corporation shall
have authority to issue is 3,000 shares of Common Stock, $.01 par value per
share. Each share of Common Stock shall be entitled to one vote.

            5. The name and mailing address of the incorporator is Denise M.
Annunciata, c/o Ropes & Gray, One International Place, Boston, Massachusetts
02110-2624.

            6. Except as otherwise provided in the provisions establishing a
class of stock, the number of authorized shares of any class or series of stock
may be increased or decreased (but not below the number of shares thereof then
outstanding) by the affirmative vote of the holders of a majority of the voting
power of the corporation entitled to vote irrespective of the provisions of
Section 242(b)(2) of the General Corporation Law of the State of Delaware.

            7. The election of directors need not be by written ballot unless
the by-laws shall so require.

            8. In furtherance and not in limitation of the power conferred upon
the board of directors by law, the board of directors shall have power to make,
adopt, alter, amend and repeal from time to time by-laws of this corporation,
subject to the right of the stockholders entitled to vote with respect thereto
to after and repeal by-laws made by the board of directors.

            9. A director of this corporation shall not be liable to the
corporation or its stockholders for monetary damages for breach of fiduciary
duty as a director, except to the extent that exculpation from liability is not
permitted under the General Corporation Law of the State of Delaware as in
effect at the time such liability is



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determined. No amendment or repeal of this paragraph 9 shall apply to or have
any effect on the liability or alleged liability of any director of the
corporation for or with respect to any acts or omissions of such director
occurring prior to such amendment or repeal.

            10. This corporation shall, to the maximum extent permitted from
time to time under the law of the State of Delaware, indemnify and upon request
advance expenses to any person who is or was a party or is threatened to be made
a party to any threatened, pending or completed action, suit, proceeding or
claim, whether civil, criminal, administrative or investigative, by reason of
the fact that such person is or was or has agreed to be a director or officer of
this corporation or while a director or officer is or was serving at the request
of this corporation as a director, officer, partner, trustee, employee or agent
of any corporation, partnership, joint venture, trust or other enterprise,
including service with respect to employee benefit plans, against expenses
(including attorney's fees and expenses), judgments, fines, penalties and
amounts paid in settlement incurred (and not otherwise recovered) in connection
with the investigation, preparation to defend or defense of such action, suit,
proceeding or claim; provided, however, that the foregoing shall not require
this corporation to indemnify or advance expenses to any person in connection
with any action, suit, proceeding, claim or counterclaim initiated by or on
behalf of such person. Such indemnification shall not be exclusive of other
indemnification rights arising under any by-law, agreement, vote of directors or
stockholders or otherwise and shall inure to the benefit of the heirs and legal
representatives of such person. Any person seeking indemnification under this
paragraph 10 shall be deemed to have met the standard of conduct required for
such indemnification unless the contrary shall be established. Any repeal or
modification of the foregoing provisions of this paragraph 10 shall not
adversely affect any right or protection of a director or officer of this
corporation with respect to any acts or omissions of such director or officer
occurring prior to such repeal or modification.

            11. The books of this corporation may (subject to any statutory
requirements) be kept outside the State of Delaware as may be designated by the
board of directors or in the by-laws of this corporation.

            12. If at any time this corporation shall have a class of stock
registered pursuant to the provisions of the Securities Exchange Act of 1934,
for so long as such class is so registered, any action by the stockholders of
such class must be taken at an annual or special meeting of stockholders and may
not be taken by written consent.



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            THE UNDERSIGNED, the sole incorporator named above, hereby certifies
that the facts stated above are true as of this 28th day of December, 1998.

                                          /s/ Denise M. Annunciata
                                          --------------------------------------
                                          Denise M. Annunciata
                                          c/o Ropes & Gray
                                          One International Place
                                          Boston, Massachusetts 02110-2624


                            CERTIFICATE OF AMENDMENT
                                       OF
                          CERTIFICATE OF INCORPORATION
                                       OF
                         LINEAL ACQUISITION CORPORATION

      Lineal Acquisition Corporation (the "Corporation"), a corporation
organized and existing under and by virtue of the General Corporation Law of the
State of Delaware, does hereby certify:

      First: That the Board of Directors of said corporation by unanimous
written consent, adopted the following resolution:

      RESOLVED That the Board of Directors hereby declares it advisable and in
the best interest of the Corporation that Article 1 of the Certificate of
Incorporation be amended to read as follows:

      "1. The name of this Corporation is "Lineal Technologies, Inc."

      Second: That said amendment has been consented to and authorized by the
holders of a majority of the issued and outstanding stock entitled to vote
thereon by written consent given in accordance with the provisions of Section
228 of the General Corporation Law of the State of Delaware and that prompt
notice of the taking of the foregoing action without a meeting has been given to
those stockholders who have not consented in writing pursuant to Section 228(d)
thereof.

      Third: That said amendment was duly adopted in accordance with the
applicable provisions of Sections 242 and 228 of the General Corporation Law of
the State of Delaware.

      IN WITNESS WHEREOF, said corporation has caused this Certificate to be
signed by John B. Ayer, its Vice President.

EXECUTED this 12th day of January, 1999.

                                              /s/ John B. Ayer
                                              ---------------------------------
                                              John B. Ayer, Vice President