Developing CBTC system safety requirement hierarchy through STPA methodology.

Safety-critical systems, such as the railway signal system, are subject to potentially high costs from failures, including loss of life and property damage. The use of new technology, including communication-based train control (CBTC) systems with software and computers, has changed the types of accidents that occur. Software-related issues and dysfunctional interactions between system components controlled by the software are increasingly the cause of incidents. Developing a "safe" safety-critical system requires accurate and complete safety requirements, which are the foundation of system development. Traditional hazard analysis techniques are insufficient for identifying the causes of accidents in modern railway signaling systems. Systems-Theoretic Process Analysis (STPA) is a powerful new hazard analysis method designed to address these limitations. Building upon this foundation, a hierarchical approach to safety requirement development has been further developed. This approach combines STPA analysis with a hierarchical modeling approach to establish traceability links from safety requirements to specific architectures, refine and allocate system-level safety requirements to relevant subsystems, and abstract safety requirements at higher hierarchical levels to enable easy changes to lower-level implementations. This paper employs the aforementioned methodology within the context of the CBTC system, thereby enhancing risk management and hazard analysis, enabling early insights, and facilitating the generation of safety requirements of CBTC System.

Modulating covalent organic frameworks with accessible carboxyl to boost superior extraction of polar nitrobenzene compounds from matrix-complicated beverages.

The wide use and high polarity of nitrobenzene compounds (NBCs) have caused a concern for their residues in daily beverages. Herein, the covalent organic frameworks (COFs) with abundant carboxyl were ingeniously designed by introducing a novel modulator, and further developed as solid phase microextraction (SPME) coatings. Due to the enhanced polar interaction, the extraction efficiencies of modified COF for NBCs were sharply increased. After coupling the high-performance SPME fiber with gas chromatograph-mass spectrometry (GC-MS), an ultrasensitive analytical method was developed, with a wide linear range (0.50-5000 ng/L), and low limits of detection (0.15-3.0 ng/L). More importantly, the method was highly feasible and practical, leading to the precise determinations of trace NBCs from variously matrix-complicated samples. This work provides a viable and efficacious approach for the extraction and analysis of polar pollutants form complicated matrices, and is of great significance for mild COF modification and its extended applications in analytical chemistry.

A tooth-supported titanium mesh bending and positioning module for alveolar bone augmentation and improving accuracy.

OBJECTIVE: Guided bone regeneration with titanium mesh is a commonly used bone augmentation technique. However, deformation and sliding may occur during the installation of titanium mesh, which may lead to poor accuracy of bone augmentation. This article presented three cases, which describe a tooth-supported titanium mesh bending and positioning module aiming to improve the precision of bone augmentation. CLINICAL CONSIDERATIONS: After designing the ideal bone increment volume digitally, print out the difference bone module between the ideal and existing bone mass and one or two wings. The wings are supported by the adjacent teeth to show the ideal bone mass in the patients' mouth. Finally, the titanium mesh is bent and installed in the ideal position by the module. CONCLUSIONS: A favorable outcome has been preliminarily confirmed in these cases, the average vertical bone gain was 4.16 mm and the average horizontal gain was 7.48 mm after 6 months. Using the module in the treatment of patients with bone augmentation can effectively improve the accuracy, the maximum deviation was 1.5 mm and the mean was 0.6 mm. CLINICAL SIGNIFICANCE: This study improves the bone augmentation technology with titanium mesh. The titanium mesh is fixed in the ideal position, which facilitates subsequent implantation and denture repair.

[Research rules of famous veteran traditional Chinese medicine practitioners in treating infertility].

To explore the medication rules of famous veteran traditional Chinese medicine practitioners in treating infertility based on medical cases of infertility collected from book series of Hundred Traditional Chinese Medicine Clinicians of Hundred Years in China and Prescription Proven by Traditional Chinese Medicine Masters. Researchers extracted the information of prescriptions from these cases according to the inclusion and exclusion criteria. Then, Excel 2010, SPSS Clementine(ver.12.0) and SPSS(ver. 22.0) were adopted respectively for frequency analysis, association rules analysis, cluster analysis and factor analysis. Cluster analysis was carried out by Ochiai algorithm of binary variable data, which was a systematic clustering method. And principal component analysis was used for factor analysis. Besides, KMO test and Bartlett spherical test were used for factor adaptation test. Finally, 151 medical cases and 396 prescriptions were included in total. A total of 60 kinds of frequently used herbs were identified according to the results of frequency analysis for medication, they were mainly used for activating blood and resolving stasis, tonifying and clearing heat respectively. The association rules analysis found out 25 drug pair association rules and 14 3-drug combination association rules. A total of 15 medicine groups were extracted by cluster analysis. KMO test and Bartlett spherical test indicated that the method was suitable for factor analysis, and 21 common factors were respectively extracted by factor analysis. Association rules indicated the characteristics of the therapeutic methods, like tonifying Qi and replenishing blood. The famous veteran traditional Chinese medicine practitioners utilized modified Siwu Decoction for tonifying blood and preferred Atractylodis Macrocephalae Rhizoma(Baizhu) for tonifying Qi. The results of both cluster analysis and factor analysis demonstrated the characteristics of the therapies for tonifying kidney, activating blood, tonifying spleen and dispelling dampness. In addition, factor analysis could reflect the therapies for nourishing Yin, tonifying kidney, warming the meridian, dissipating cold, nourishing blood and dispelling blood stasis. These results of analysis comprehensively showed out the medication characteristics of famous veteran traditional Chinese medicine practitioners of strictly following the pathogenesis, making good use of classical formulas and providing proper compatibility. In conclusion, data mining techniques(including frequency analysis, association rules analysis, cluster analysis and factor analysis) were used to comprehensively analyze the medication rules of famous veteran traditional Chinese medicine practitioners in treating infertility, which is helpful for guiding the clinical practice of treating infertility with traditional Chinese medicine.