EXHIBIT 1 JOINT FILING AGREEMENT The undersigned hereby agree to the joint filing of the Schedule 13G to which this Agreement is attached. Dated: February 14, 2006 OBERWEIS ASSET MANAGEMENT, INC.

                                                                      EXHIBIT 1

                            JOINT FILING AGREEMENT

   The undersigned hereby agree to the joint filing of the Schedule 13G to
which this Agreement is attached.

Dated: February 14, 2006

                                              OBERWEIS ASSET MANAGEMENT, INC.

                                              By: /s/ Xxxxxxx X. Xxxxx
                                                  ------------------------------
                                                  Xxxxxxx X. Xxxxx
                                                  Executive Vice President

                                                  /s/ Xxxxx X. Xxxxxxxx
                                                  ------------------------------
                                                  XXXXX X. XXXXXXXX

                                                  /s/ Xxxxx X. Xxxxxxxx
                                                  ------------------------------
                                                  XXXXX X. XXXXXXXX

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