FREPA: An Automated and Formal Approach to Requirement Modeling and Analysis in Aircraft Control Domain

Formal methods are promising for modeling and analyzing system requirements. However, applying formal methods to large-scale industrial projects is a remaining challenge. The industrial engineers are suffering from the lack of automated engineering methodologies to effectively conduct precise requirement models, and rigorously validate and verify (V&V) the generated models. To tackle this challenge, in this paper, we present a systematic engineering approach, named Formal Requirement Engineering Platform in Aircraft (FREPA), for formal requirement modeling and V\&V in the aerospace and aviation control domains. FREPA is an outcome of the seamless collaboration between the academy and industry over the last eight years. The main contributions of this paper include 1) an automated and systematic engineering approach FREPA to construct requirement models, validate and verify systems in the aerospace and aviation control domain, 2) a domain-specific modeling language AASRDL to describe the formal specification, and 3) a practical FREPA-based tool AeroReq which has been used by our industry partners. We have successfully adopted FREPA to seven real aerospace gesture control and two aviation engine control systems. The experimental results show that FREPA and the corresponding tool AeroReq significantly facilitate formal modeling and V&V in the industry. Moreover, we also discuss the experiences and lessons gained from using FREPA in aerospace and aviation projects.Comment: 12 pages, Published by FSE 202

Tourism experiences reduce the risk of cognitive impairment in the Chinese older adult: A prospective cohort study

Background: Given the etiological complexity of cognitive impairment, no effective cure currently exists for precise treatment of dementia. Although scholars have noted tourism’s potential role in managing cognitive impairment and mild dementia, more robust empirical investigation is needed in this area. This study aimed to examine the associations between tourism and cognitive impairment and dementia in older Chinese adults. Method: From a nationwide community-based cohort, 6,717 individuals aged ≥ 60 were recruited from 2011 to 2014, of whom 669 (9.96%) had had at least one tourism experience in the 2 years prior to enrollment. All the participants were then prospectively followed up until 2018. The association between tourism and cognitive impairment was examined by the Cox proportional hazards regression model. The adjusted hazard ratio (aHR) and its 95% confidence interval (CI) were calculated to evaluate the effect of tourism experience on cognitive impairment and dementia. Results: A total of 1,416 individuals were newly diagnosed with cognitive impairment and 139 individuals with dementia onset during follow-up. The incidence of cognitive impairment was significantly lower among participants with tourism experiences (316.94 per 10,000 person-years) than those without such experiences (552.38 per 10,000 person-years). Cox regression showed that tourism decreased the risk of cognitive impairment (aHR = 0.69, 95% CI: 0.41–0.62) when adjusted for behavioral covariates and characteristics. Compared with participants without tourism experiences, those with 1, 2, and ≥ 3 tourism experiences had a lower risk of cognitive impairment with the aHRs of 0.72 (95% CI: 0.52–0.99), 0.65 (0.42–1.01), and 0.68 (0.44–0.98), respectively. Tourism experiences also reduced participants’ risk of dementia (aHR = 0.41, 95% CI: 0.19–0.89). Conclusion: Our findings demonstrated associations between tourism and reduced risks of cognitive impairment and dementia in older Chinese adults. Thus, tourism could serve as a novel approach to dementia prevention

Experimental study of aerospace solid propellant fracturing in simulated coal sample

Coal reservoirs with high gas content and low permeability seriously restrict the efficient production of coal and coalbed methane. It is necessary to fracture and enhance the permeability of coal reservoirs. Aerospace solid propellant deflagration can generate a large amount of high-energy gas to impact coal reservoirs, which can achieve the purpose of fracturing and enhancing permeability of coal reservoirs. To study the characteristics of aerospace solid propellant for fracturing coal, a solid propellant for fracturing and permeability enhancement of coal reservoir was firstly researched and developed based on the formula of civil aerospace solid propellant, was, and its performance, sensitivity, pressure and temperature resistance were tested. The aerospace solid propellant fracturing test was then carried out using simulated coal samples, and the borehole wall pressure and strain within the simulated coal samples were monitored during the test. Finally, the destruction characteristics of simulated coal samples were analyzed according to the test results. The results shown that the aerospace solid propellant had good performance, with the advantages of waterproof, pressure resistant, and no CO generation, which could be adapted to the underground environment of coal mine. During the test, the time curve of the borehole wall pressure shown the stages of rapid pressure rise, slow pressure rise, and nonlinear pressure drop, in which the rise time of the borehole wall pressure was about 18 ms. The peak pressure in the borehole was low and unevenly distributed. The peak pressure in the middle of the borehole was 118.1 MPa, and the peak pressure at the bottom of the borehole was 85.3 MPa. Stress wave generated in simulated coal sample during aerospace solid propellant fracturing was composed of compressive and tensile phases with low intensity, long duration and slow decay with distance. The aerospace solid propellant fracturing technology was dominated by the quasi-static action of high-energy gas, with high utilization of stress wave energy. The research results provide a reference for the application of aerospace solid propellant in the field of coalbed methane mining

Identification of Ancient Chinese Medical Prescriptions and Case Data Analysis Under Artificial Intelligence GPT Algorithm: A Case Study of Song Dynasty Medical Literature

This work aims to use the chatGPT algorithm to analyze and summarize cases in medical literature of the Song Dynasty, understand the clinical practice experience of ancient Chinese medicine, and provide historical reference for the clinical application and research of modern Chinese medicine. Firstly, the application of Artificial Intelligence (AI) in medicine is explained through literature research. Secondly, the prescription recognition technology related to AI is introduced, and a method combining supervised learning and semi-supervised learning for prescription entity recognition is proposed. Combined with chatGPT technology, medical data mining is carried out to obtain information and knowledge of medical research in the Song Dynasty. chatGPT is applied to the identification of ancient Chinese medical prescriptions and the analysis of case data. The results show that: 1) machine classifier performs well in classifying different flavor compounds, effective and ineffective prescriptions can be distinguished, and the accuracy increases with the increase of samples; 2) data mining reveals the differences in disease stages, the primary and secondary contradictions in patients’ bodies, and the primary and secondary differences in drug use; 3) frequency statistics show that warm drugs account for 45.46%, confirming that warm drugs are the main ones for treating phlegm. Therefore, it is recommended to use chatGPT as an auxiliary tool in medical-related analysis and combine it with professional medical knowledge and clinical practice for comprehensive judgment and decision-making. Ancient medical prescriptions can be better identified, and case data can be analyzed by combining chatGPT technology in AI. It can well support ancient medicine study and lay a solid foundation for developing modern medical information data warehouse

Modeling and Simulation of Traction Power Supply System for High-Speed Maglev Train

The electromagnetic suspension high-speed maglev train system uses long-stator linear synchronous motors (LLSMs) as levitation and traction mechanisms. In this paper, the modeling and simulation of the traction power supply system for the maglev train are performed. The simulation models include transformers, converters, variable-length cables and LLSMs of both two sides and two ends; meanwhile, the corresponding control and segmented power supply strategies, including the two-step method and three-step method, are implemented. Based on the system model, the operational performance of the high-speed maglev power supply control system is verified, and the fault performances under open circuit and short circuit are also analyzed. The whole simulation modeling and results have important reference significance for the research of high-speed maglev technology

Experimental Study on High-Energy Gas Fracturing Artificial Coal

The low permeability of coal seams has always been the main bottleneck restricting coalbed gas drainage. To improve the permeability of a coal seam, a high-energy gas fracturing technology is proposed. Firstly, based on the high-energy gas fracturing mechanism and gas production principle of fracturing agent, a fracturing agent applicable to coal reservoirs was developed, and its performance and sensitivity were tested. Then, a high-energy gas-fracturing simulated coal sample test was conducted, and the drilling wall pressure and strain of the simulated coal sample were tested. The results show that high-energy gas fracturing technology is a safe and efficient technical means for improving the permeability of coal reservoirs. The pressure–time curve of the borehole wall under the action of high-energy gas can be divided into three stages, namely, the rapid pressure-rising stage, steady pressure stage, and falling stage; the maximum pressure in the borehole is about several hundred MPa, and the pressure distribution in the borehole is not uniform. Compared with explosives blasting, the stress wave intensity in coal caused by the action of high-energy gases is low, the duration is short, and the peak stress attenuates slowly with increasing distance. Under the action of high-energy gas, no crush zone is generated near the borehole; the number of radial cracks produced is small but long. The extent of the fracture zone depends mainly on the quasi-static splitting wedge effect of the high-energy gas

Experimental Study on High-Energy Gas Fracturing Artificial Coal

The low permeability of coal seams has always been the main bottleneck restricting coalbed gas drainage. To improve the permeability of a coal seam, a high-energy gas fracturing technology is proposed. Firstly, based on the high-energy gas fracturing mechanism and gas production principle of fracturing agent, a fracturing agent applicable to coal reservoirs was developed, and its performance and sensitivity were tested. Then, a high-energy gas-fracturing simulated coal sample test was conducted, and the drilling wall pressure and strain of the simulated coal sample were tested. The results show that high-energy gas fracturing technology is a safe and efficient technical means for improving the permeability of coal reservoirs. The pressure–time curve of the borehole wall under the action of high-energy gas can be divided into three stages, namely, the rapid pressure-rising stage, steady pressure stage, and falling stage; the maximum pressure in the borehole is about several hundred MPa, and the pressure distribution in the borehole is not uniform. Compared with explosives blasting, the stress wave intensity in coal caused by the action of high-energy gases is low, the duration is short, and the peak stress attenuates slowly with increasing distance. Under the action of high-energy gas, no crush zone is generated near the borehole; the number of radial cracks produced is small but long. The extent of the fracture zone depends mainly on the quasi-static splitting wedge effect of the high-energy gas

Promoting or inhibiting? Green fiscal policy and urban green innovation

Can green fiscal policy (GFP) incentivize the proliferation of urban green innovation (GI) and be a novel catalyst for energy conservation and emission reduction within the “dual-carbon” framework? This paper explores GFP ramifications for GI by implementing a difference-in-differences model in a natural experiment centered on the “Comprehensive Demonstration City of Energy Saving and Emission Reduction Fiscal Policies”. The empirical analysis reveals several key findings: (1) GFP exhibits significant augmentation at the GI level, with an observable evolutionary trend of increasing marginal impact. Importantly, these outcomes withstand rigorous robustness tests, including propensity score matching. (2) A mechanism analysis elucidates the dual impact of GFP on GI growth. GFP directly fosters GI advancement indirectly by promoting talent aggregation, expanding scientific and technological investment, and attracting external financial resources. (3) A heterogeneity analysis demonstrates that GFP enhancement of GI is closely associated with the patent category, manifesting a distinct pattern of “eastern region > other regions” and “non-resource cities > resource cities”. The study’s empirical findings offer crucial real-world insights to guide the Chinese government in formulating a more efficient GFP and facilitating the expansion of innovative endeavors while contributing to environmentally sustainable and high-value development

Synthesis of CuS/ZnO Nanocomposite and Its Visible-Light Photocatalytic Activity

The CuS/ZnO nanocomposite was successfully synthesized by a simple mechanical method, without adding any surfactants. TEM images showed that CuS existed in the nanocomposite and the size of CuS/ZnO nanocomposite particle was around 35 nm. CuS worked as an electron absorber in the nanocomposite, which was beneficial for the improvement of photocatalysis of ZnO. It was also proved by the experiments performed under the visible light irradiation that CuS could help ZnO degrade methylene blue (MB). The catalytic efficiency of the nanocomposites reached the highest value when 0.5 wt% CuS was added. In addition, compared with pure ZnO, the CuS/ZnO nanocomposite exhibited a better photochemical stability up to 5 catalytic cycles. More importantly, CuS did not reduce the antibacterial property of ZnO. All these results indicated that as-prepared samples had some potential values in practical applications