Average Co-Inventor Count = 6.15
ph-index = 2
The patent ph-index is calculated by counting the number of publications for which an author has been cited by other authors at least that same number of times.
Company Filing History:
1. Hitachi, Ltd. (2 from 42,517 patents)
2. Hitachi Information Control Systems, Inc. (1 from 9 patents)
2 patents:
1. 6218963 - Time management system for passing vehicles
2. 5737513 - Method of and system for verifying operation concurrence in