A numerical framework for the simulation of sheet steel stamping forming is presented. The main problems, the equations of motion, the constitutive relation, the initial conditions, boundary conditions and contact conditions, are presented in detail. Based on this, the finite element model is established and solved for exploring the changes in laws of stress, strain and so on. The information o...

PIG (Pin-Injection-Gate) die-casting and hot stamping was developed for fabrication of small-sized thin-walled aluminum alloy parts from the recycled feedstock. The pure granules were utilized as a feedstock model materials. measured mass with estimated weight 3D-CAD (Computer Aided Design) products poured into PIG-nozzles before injection. After quickly melting by induction heating inside PIG-...

As the Internet grows in scale almost every year, security measures are expected to become all the more important on the Internet. A Time-stamping authority (TSA) is a trusted authority which provides a proof that a datum existed before a particular time. In this research, we implemented a RFC-3161 compliant time-stamping service over the Internet. The TSA server software was implemented on Lin...

It is well known that there are 17 crystallographic groups that determine the possible tessellations of the Euclidean plane. We approach them from an unusual point of view. Corresponding to each crystallographic group there is an orbifold. We show how to think of the orbifolds as artifacts that serve to create tessellations. 1. TESSELLATIONS. The history of human civilization gives an enormous ...

of Thesis Presented to the Graduate School of the University of Florida in Partial Ful llment of the Requirements for the Degree of Master of Science A FORMAL APPROACH TO TWO-DIMENSIONAL TEMPORAL DATABASES By Seung-Kyum Kim May, 1993 Chairman: Dr. Sharma Chakravarthy Major Department: Computer and Information Sciences In this thesis, we propose a formal de nition of temporal validity, which we ...

Even using an authenticated synchronous broadcast model, the task of unforgeably time-stamping digital documents still presents some problems. It is simply not practical to assume that all participants will record and store everyone else's documents so that creation times can be veri ed. This paper presents a time and space e cient method for accumulation of time-stamped documents. Whenever a q...