Existing data embedding algorithms for polygonal meshes and their attributes can't be applied to the majority of (geometric) computer aided design (CAD) applications, for two major reasons. First, these CAD systems employ parametric curves and surfaces, not polygonal meshes, as their main shape-defining primitives. Second, most CAD applications do not tolerate modifications of model topology and/or geometry that are introduced by existing data embedding algorithms.This paper proposes a new data embedding algorithm for non-uniform rational B-spline (NURBS) curves and surfaces, which employs rational linear reparameterization for embedding messages. The algorithm exactly preserves the shape, -that is, the geometry and topology -of its embedding targets. Furthermore, it preserves the data size of the model. We consider these two properties, preservation of shape and preservation of data size, can be significant with regard to the use of data embedding in CAD applications.In addition to the shape-and data size-preserving data embedding algorithm for NURBS curves and surfaces, this paper outlines additional methods for embedding data in various types of parametric curves and surfaces.

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Objectives To determine: (i) whether the accuracy of 0.680 for PSA, 0.684 for PSAD, 0.764 for PSAT, 0.748 for cSP/PSA, 0.885 for cSP/PSA in patients prostate-specific antigen (PSA) density is improved by using the transition zone (TZ) volume instead of total with a prostate volume <40 mL, while it was 0.817 for PSAT in patients with a prostate volume of prostate volume, with the c-seminoprotein (cSP, a measure of free PSA) to total PSA ratio, for detecting Á40 mL. Using a PSAT threshold of 0.17 in patients with a prostate volume of 40 mL, the number of prostate cancer; and (ii) to assess the influence of prostate volume on PSA density and cSP/PSA ratio.biopsies was reduced by 56% (66 of 118) and 22 of the 25 cancers (88%) were detected. In addition, a Patients and methods From April 1995 to July 1997, 297 consecutive patients (46-88 years old) were cSP/PSA ratio threshold of 40% in patients with a prostate volume of <40 mL decreased the number examined; all had intermediate serum PSA levels (4-10 ng/mL) and/or abnormal findings on digital of biopsies by 75% (88 of 117) and detected 32 of the 37 cancers (87%). rectal examination. All patients underwent transrectal ultrasonography (TRUS)-guided biopsy, and the prosConclusions Prostate volume was significantly and positively correlated with cSP/PSA and negatively corretate and TZ volumes determined from TRUS. The PSA density relative to the total prostate volume (PSAD) lated with PSAT. Among patients with a PSA level of 4-10 ng/mL, a low cSP/PSA was most useful for and to the TZ volume (PSAT) were then calculated. The total PSA and cSP levels were measured before detecting prostate cancer when the prostate volume was <40 mL and a high PSAT was useful when the the diagnostic procedures. Results Of the 297 patients, 62 (21%) were histologically prostate volume was Á40 mL.

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