Pen-input is not a new means for CAD designers, in particular, in the concept design phase. Meanwhile, B-Splines are well known curve and surface design tool in 3D shape modeling in the final modeling stages in which neat curves and surfaces should be produced. In this paper, an intuitive B-Spline design method that can be used for the CAD systems both in conceptual modeling phase and in later design phases is proposed. Unlike the control point based interactive modification schemes for the B-spline curves and surfaces, we extend what has been called the "touch-and-replace" method used for poly-line modification in the late 1980s to B-Splines; our approach uses successive pen strokes to modify the final shape of the existing B-Spline curves and surfaces. We also show related user test results in this paper as an empirical proof.

In this paper, a new handover procedure for OFDM-based multi-hop relay systems is proposed to reduce handover overhead by distinguishing an inter-cell handover event from an intra-cell handover event at the level of the physical layer using a preamble with a hierarchical design. A Subcell ID concept used to identify relay station in a cell is proposed in the hierarchical design that works in conjunction with the existing Cell ID used to identify base station. The proposed handover procedure can simplify the scanning procedure and skip/simplify the network re-entry procedure, resulting in a significant reduction in handover overhead.