High-Precision Positioning and Rotation Angle Estimation for a Target Pallet Based on BeiDou Navigation Satellite System and Vision.

In outdoor unmanned forklift unloading scenarios, pallet detection and localization face challenges posed by uncontrollable lighting conditions. Furthermore, the stacking and close arrangement of pallets also increase the difficulty of positioning a target pallet. To solve these problems, a method for high-precision positioning and rotation angle estimation for a target pallet using the BeiDou Navigation Satellite System (BDS) and vision is proposed. Deep dual-resolution networks (DDRNets) are used to segment the pallet from depth images and RGB images. Then, keypoints for calculating the position and rotation angle are extracted and further combined with the 3D point cloud data to achieve accurate pallet positioning. Constraining the pixel coordinates and depth coordinates of the center point of the pallet and setting the priority of the pallet according to the unloading direction allow the target pallet to be identified from multiple pallets. The positioning of the target pallet in the forklift navigation coordinate system is achieved by integrating BDS positioning data through coordinate transformation. This method is robust in response to lighting influences and can accurately locate the target pallet. The experimental results show that the pallet positioning error is less than 20 mm, and the rotation angle error is less than 0.37°, which meets the accuracy requirements for automated forklift operations.

High Precision Positioning and Rotation Angle Estimation of a Flatbed Truck Based on BDS and Vision.

Centimeter-level localization and precise rotation angle estimation for flatbed trucks pose significant challenges in unmanned forklift automated loading scenarios. To address this issue, the study proposed a method for high-precision positioning and rotation angle estimation of flatbed trucks using the BeiDou Navigation Satellite System (BDS) and vision technology. First, an unmanned forklift equipped with a Time-of-Flight (ToF) camera and a dual-antenna mobile receiver for BDS positioning collected depth images and localization data near the front and rear endpoints of the flatbed. The Deep Dual-Resolution Network-23-slim (DDRNet-23-slim) model was used to segment the flatbed from the depth image and extract the straight lines at the edges of the flatbed using the Hough transform. The algorithm then computed the set of intersection points of the lines. A neighborhood feature vector was designed to identify the endpoint of a flatbed from a set of intersection points using feature screening. Finally, the relative coordinates of the endpoints were converted to a customized forklift navigation coordinate system by BDS positioning. A rotation angle estimation was then performed using the endpoints at the front and rear. Experiments showed that the endpoint positioning error was less than 3 cm, and the rotation angle estimation error was less than 0.3°, which verified the validity and reliability of the method.

LncRNA PACER is down-regulated in osteoarthritis and regulates chondrocyte apoptosis and lncRNA HOTAIR expression.

LncRNA PACER is a chondrocyte inflammation-associated long non-coding RNA (lncRNA), and chondrocyte inflammation is involved in osteoarthritis (OA). We observed that plasma PACER was down-regulated, while plasma HOTAIR was up-regulated in OA patients. Altered plasma levels of PACER and HOTAIR distinguished OA patients from healthy controls. PACER and HOTAIR were inversely correlated in both OA patients and healthy controls. PACER overexpression mediated the down-regulation of HOTAIR, while HOTAIR overexpression did not significantly affect PACER. PACER overexpression led to inhibited, while HOTAIR overexpression led to promoted apoptosis of chondrocyte. HOTAIR overexpression attenuated the effects of PACER overexpression. Therefore, lncRNA PACER is down-regulated in OA and regulates chondrocyte apoptosis by down-regulating lncRNA HOTAIR.

[IMPROVED DOUBLE OPERATIVE APPROACHES FOR TREATMENT OF Pilon FRACTURES ACCOMPANIED WITH FIBULA FRACTURES].

OBJECTIVE: To investigate the clinical effect of surgical treatment of Pilon fractures accompanied with fibula fractures with the improved double operative approaches. METHODS: Between January 2012 and June 2015, 19 patients with closed Pilon fractures accompanied with fibula fractures (Rüedi-Allgöwer type Ⅲ) underwent open reduction and internal fixation with improved anterior-median incision and posterior-lateral incision. There were 13 males and 6 females, aged 35 years on average (range, 23-68 years). Injury was caused by traffic accident in 11 cases, falling from height in 7 cases, and crash injury of heavy object in 1 case. According to AO/OTA classification, there were 4 cases of type C2, and 15 cases of type C3. According to Tscherne-Gotzen classification of soft tissue defect, 6 cases were rated as grade 1 and 13 cases as grade 2. The interval of injury and operation was 6-18 days (mean, 10.3 days). After operation, reduction of Pilon fracture was evaluated by the Burwell-Charnley radiological evaluation criteria, and the ankle joint function was evaluated by the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score. RESULTS: The operation time was 1.8-4.6 hours (mean, 2.4 hours); the intraoperative blood loss was 200-500 mL (mean, 310 mL). All the 19 patients were followed up for 13.7 months on average (range, 12-18 months). The fracture healing time was 3.6 months on average (range, 2.5-8.0 months). Postoperative complications included anterior-median incision necrosis in 2 cases, traumatic arthritis in 2 cases, and ankle instability in 1 case. According to Burwell-Charnley radiological evaluation criteria, anatomical reduction was obtained in 15 cases and satisfactory reduction in 4 cases. According to AOFAS score, the excellent and good rate was 84.2% (excellent in 11 cases, good in 5 cases, and fair in 3 cases). CONCLUSIONS: The improved anterior-median incision combined with posterior-lateral incision is a safe and effective method to treat complex Pilon fractures accompanied with fibula fractures, which has the advantages of simple operation, adequate exposure and minimal invasion.