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Purpose: Problem-solving" is the most crucial key insight of scientific research. This study focuses on constructing the "problem-solving" knowledge graph of scientific domains by extracting four entity relation types: problem-solving, problem hierarchy, solution hierarchy and association. Design/methodology/approach: This paper presents a low-cost method for identifying these relationships in scientific papers based on word analogy. The problem-solving and hierarchical relations are represented as offset vectors of the head and tail entities and then classified by referencing a small set of predefined entity relations. Findings: This paper presents an experiment with artificial intelligence papers from the Web of Science and achieved good performance. The F1 scores of entity relation types problem hierarchy, problem-solving and solution hierarchy, which were 0.823, 0.815 and 0.748, respectively. This paper used computer vision as an example to demonstrate the application of the extracted relations in constructing domain knowledge graphs and revealing historical research trends. Originality/value: This paper uses an approach that is highly efficient and has a good generalization ability. Instead of relying on a large-scale manually annotated corpus, it only requires a small set of entity relations that can be easily extracted from external knowledge resources. [ABSTRACT FROM AUTHOR]

As one of the key techniques used in the perception layer of the Industrial Internet of Things (IIoT), radio frequency identification (RFID) has been widely applied for object tracing, smart warehouse management, product line monitoring, etc. In most applications, conveyor belts are prevalently implemented to accelerate the sorting efficiency for goods management. However, in such a system, tags quickly go through the reader's reading range resulting in constant changing of the tag set and limited participating time of moving tags. As a result, it poses more challenges to the tag identification problem in mobile systems than in traditional static applications. In this work, a novel admission-control-based dynamic query tree (ACDQT) protocol is proposed for fast-moving tag identification. In ACDQT, two main strategies are developed, i.e., multi-round admission control (MRAC) and dynamic query tree recognition (DQTR). In MRAC, the reading process of multiple rounds is analyzed, and the number of admitted tags in each round is optimized. Thus, the tag lost ratio is guaranteed, and the identification process can be effectively accelerated. In DQTR, colliding tags are grouped into multiple subsets with the help of consecutive colliding bits in tag responses. By constructing a dynamic query tree, the number of collision slots is greatly reduced, and the identification efficiency in a single round is improved significantly. With MRAC and DQTR, ACDQT can support higher tag flow rate in mobile systems than existing works. Both theoretical analyses and simulation results are presented to demonstrate the effectiveness of ACDQT. [ABSTRACT FROM AUTHOR]

Developing efficient and low-cost bi-functional electrolytes for energy applications such as fuel cells and rechargeable metal-air batteries is highly desirable. Here, we have synthesized spinel Ni 0. 5 Cu 0. 5 Co2O4 (NCC) nanoparticles as nonprecious bi-functional electrocatalysts by a simple hydrothermal reaction method. The phase structure and the morphology of NCC nanoparticles have been investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) while the electrocatalytic activity of the samples has been studied in alkaline solution by using rotating disk electrode technique. The electrocatalysts have showed a comparable ORR and OER catalytic activities compared with of those of the other transition metal oxides, suggesting the feasibility of the NCC as the bi-functional electrolytes materials for ORR and OER. [ABSTRACT FROM AUTHOR]

Objective: To explore the treatment methed of recurrent patellar dislocation associated with old osteochondral fracture and to evaluate its effectiveness., Methods: Between August 2010 and August 2014, 12 cases of recurrent patellar dislocation with old osteochondral fracture were treated. There were 4 males and 8 females with an average age of 18.3 years (range, 15-24 years). The left knee was involved in 7 cases and the right knee in 5 cases. All the patients had a history of patellar dislocation, the average interval from injury to first hospitalization was 7.6 months (range, 6-13 months). At preoperation, the range of motion (ROM) of the injured knee was (89.17 ± 13.11)degrees; the Lysholm score was 56.67 ± 18.91; the Q-angle was (17.50 ± 5.28)degrees; and tibial tuberosity-trochlear groove (TT-TG) distance was (18.33 ± 4.03) mm. The Q-angle was more than 20 degrees and TT-TG distance was more than 20 mm in 6 of 12 cases. There were 6 cases of patellar osteochondral fracture, 5 cases of lateral femoral condylar osteochondral fracture, and 1 case of patellar osteochondral fracture combined with lateral femoral condylar osteochondral fracture. After osteochondral fracture fragments were removed under arthroscope, lateral patellar retinaculum releasing and medial patellar retinaculum reefing was performed in 2 cases, medial patellofemoral ligament (MPFL) reconstruction combined with both lateral patellar retinaculum releasing and medial patellar retinaculum reefing in 4 cases, and MPFL reconstruction, lateral patellar retinaculum releasing, medial patellar retinaculum reefing, and tibial tubercle transfer in 6 cases. Results All wounds healed by first intention with no complication of infection, haematoma, skin necrosis, or bone nonunion. All patients were followed up 12-60 months with an average of 24.2 months. At 3 months after operation, all patellar dislocations were corrected; the Q-angle was (13.33 ± 1.37)degrees and the TT-TG distance was (12.17 ± 1.17) mm in 6 patients undergoing tibial tubercle transfer, showing significant differences when compared with preoperative values [(22.50 ± 2.17)degrees and (21.33 ± 2.34 mm (t = 15.25, P = 0.00; t = 8.27, P = 0.00. All patients achieved relief of knee pain and knee locking; the knee ROM and the Lysholm score at last follow-up were (120.42 ± 11.57)degrees and 89.25 ± 9.71, showing significant differences when compared with preoperative ones (t = -11.61, P = 0.00; t = -8.66, P = 0.00)., Conclusion: It gas satisfactory short-term effectiveness to remove old osteochondral fragments that can not be rest and to correct patellar dislocation for recurrent patellar dislocation with old osteochondral fracture.