Xiaohui Jin

Purpose: This single-phantom CT-referenced technical-validation study evaluated residual length and angular measurement bias after source-to-image distance/source-to-object distance (SID/SOD) calibration in full-length lower-limb radiography using system/protocol configurations representing rotational stitching and slot-scanning. Methods: A whole-body anthropomorphic phantom was imaged once with each of six system/protocol configurations: four rotational-stitching configurations and two slot-scanning protocols. CT-derived coronal-plane measurements from three-dimensional landmark localization served as the reference standard. Three attending radiologists performed measurements across three sessions. SID/SOD-calibrated femoral, tibial, and full-length mechanical-axis lengths; mechanical lateral distal femoral angle (mLDFA); medial proximal tibial angle (MPTA); hip-knee-ankle angle (HKA); joint line convergence angle (JLCA); and SID/SOD-calibrated 10.00 mm steel bead diameter were analyzed. Results: Slot-scanning protocols showed small negative full-length biases (Eagle Eye HQ, −5.34[Formula: see text]mm; Eagle Eye HS, −5.14[Formula: see text]mm), whereas rotational-stitching configurations showed positive full-length biases ranging from 28.66[Formula: see text]mm to 57.19[Formula: see text]mm. Angular bias behaved differently: mean mLDFA bias ranged from −0.33[Formula: see text] to 0.85[Formula: see text], MPTA from 1.57[Formula: see text] to 2.21[Formula: see text], HKA from −0.31[Formula: see text] to 0.42[Formula: see text], and JLCA from −2.08[Formula: see text] to −1.37[Formula: see text]. Mean SID/SOD-calibrated steel bead diameter bias ranged from 0.14[Formula: see text]mm to 0.88 mm; bead enlargement was smaller in the tested slot-scanning protocols, although their full-length skeletal bias was slightly negative. Conclusions: In this single-phantom technical validation, SID/SOD calibration left system/protocol-specific residual length bias. Length measurements require local verification before cross-system comparison. Angular measurements showed parameter-specific behavior and require separate validation from linear length measurements. Steel bead diameter measurements may serve as a practical quality-assurance indicator of local linear scale behavior, but they do not replace anatomical phantom validation.

Web attacks are increasing and the scale of malicious URL continues to expand with the rapid development of the Internet, so that the network security situation is increasingly grim. In this case, this paper studies the URL multi-classification problem, which is a continuation of the reference [1] and follows the data sets and most of feature selection methods in it. Firstly, different types of URL structure is analyzed and features which have obvious directivity to the attack type are increased based on the original features. Secondly, an improved semi-supervised algorithm is proposed to train the URL multi-classification model. Finally, the effect of the multi-classification model is verified by using the data set with different labeling rate, which shows the improved algorithm has good classification performance compared to the previous algorithm.