Abstract: Compositions, articles, systems, and methods for sensing and/or authentication using luminescence imaging are generally provided. In some embodiments, an article (or packaging material of an article) is associated with an emissive material comprising an emissive species (e.g., a luminescent species). In some cases, the emissive species has an emission lifetime of at least 10 nanoseconds (ns). In some cases, a characteristic of an article (e.g., identity, authenticity, age, quality, purity) may be determined by obtaining an image (or series of images) comprising time-dependent information related to an emissive species. In certain instances, for example, the emission lifetime of an emissive species may be determined from an image (or series of images). Since the emission lifetime of an emissive species may be modified by a number of factors, including but not limited to binding or proximity to other molecules (e.g.

Abstract: A signature verification system to accompany a computer-based training system to monitor the identity of the training system user. Using a stylus and digitizing pad as a computer input device, the verification system accepts a user's signature made under supervised conditions, and the computer generates various discriminator data associated with the singature, such as time to write signature, signature density and signature size. The verified, supervised signature and associated discriminator data are stored in encrypted format for security against tampering. During sessions on the training system the user is required to enter a signature at random times. Again, corresponding discriminator data for these session signatures is generated by the computer, and the session signature(s) and associated corresponding discriminator data are also likewise encrypted and stored. At a later time, e.g.