Semantic Rule Based Program Monitoring

Program monitoring aims at making sure the functionalities of the software are always correctly performed during runtime. Semantic Web provides a context enriched framework for data representation and manipulation. This paper proposed the use of ontological rules and reasoning engines to monitor the dynamic behaviours of computer systems in handling of exceptional circumstances, both positive and negative, that occur at runtime within the software processes. A prototype framework was proposed on how to integrate the rule based monitoring technique together with the targeted system. To validate the proposed solution, a light control system case study together with the Unity game engine were used to develop a simulation environment for the evaluation purpose. Compared to existing solutions, the approach outlined can provide an effective software behavioural monitoring outcome

Robust Outlier Detection Method Based on Local Entropy and Global Density

By now, most outlier-detection algorithms struggle to accurately detect both point anomalies and cluster anomalies simultaneously. Furthermore, a few K-nearest-neighbor-based anomaly-detection methods exhibit excellent performance on many datasets, but their sensitivity to the value of K is a critical issue that needs to be addressed. To address these challenges, we propose a novel robust anomaly detection method, called Entropy Density Ratio Outlier Detection (EDROD). This method incorporates the probability density of each sample as the global feature, and the local entropy around each sample as the local feature, to obtain a comprehensive indicator of abnormality for each sample, which is called Entropy Density Ratio (EDR) for short in this paper. By comparing several competing anomaly detection methods on both synthetic and real-world datasets, it is found that the EDROD method can detect both point anomalies and cluster anomalies simultaneously with accurate performance. In addition, it is also found that the EDROD method exhibits strong robustness to the number of selected neighboring samples, the dimension of samples in the dataset, and the size of the dataset. Therefore, the proposed EDROD method can be applied to a variety of real-world datasets to detect anomalies with accurate and robust performances

Increasing power densities in a thermoelectric generator by stacking and incorporating dual heat pipes

Thermoelectric generators (TEGs) hold potential for waste heat recovery applications, but their ability to generate electricity within the confined space of exhaust systems remains a challenge. This work introduces a stacked TEG with dual heat pipes to facilitate heat transfer between thermoelectric modules and hot/cold sources and to help optimize space utilization. We also designed an apparatus to assess the output performance of TEGs. Our experimental findings reveal that, at a temperature of 650 K and a flow rate of 50 m s−1, the stacked TEG can produce 848.37 W of electricity with a power density of 48.22 W L−1

The regulatory role of m6A methylation modification in metabolic syndrome pathogenesis and progression

Metabolic syndromes are characterized by various complications caused by disrupted glucose and lipid metabolism, which are major factors affecting the health of a population. However, existing diagnostic and treatment strategies have limitations, such as the lack of early diagnostic and therapeutic approaches, variability in patient responses to treatment, and cost-effectiveness. Therefore, developing alternative solutions for metabolic syndromes is crucial. N6-methyladenosine (m6A) is one of the most abundant modifications that determine the fate of RNA. m6A modifications are closely associated with metabolic syndrome development and present novel prospects for clinical applications. Aberrant m6A modifications have been detected during inflammatory infiltration, apoptosis, autophagy, iron sagging, necrosis, and scorching during metabolic syndrome pathogenesis and progression. However, few reviews have systematically described the correlation between m6A modifications and these factors concerning metabolic syndrome pathogenesis and progression. This study summarizes the m6A methylation regulators and their roles in metabolic syndrome development, highlighting the potential of m6A modification as a biomarker in metabolic disorders

Exploring the dynamic characteristics of thermoelectric generator under fluctuations of exhaust heat

The thermoelectric generator is a potential candidate to recover waste heat from exhaust gas. Regarding the fluctuations of exhaust heat in practical situations, this paper adopts a transient fluid-thermal-electric multiphysics model to investigate the dynamic performance of the thermoelectric generator. Results show that the fluctuation of exhaust temperature has a greater influence on the dynamic characteristics than the fluctuation of exhaust mass flow rate. The dynamic performance of the thermoelectric generator benefits from a decrease in exhaust heat, but suffers when the exhaust heat is in an upward trend. Compared with the constant power and efficiency values of 4.96 W and 2.49 %, the average power and efficiency of the thermoelectric generator show a notable increase of 5.50 % and 70.61 % respectively during a step decrease in exhaust mass flow rate. Similarly, under a linear decrease, the mean power and efficiency experience a rise of 6.04 % and 45.05 % respectively. Besides, periodic exhaust heat can effectively amplify the dynamic output performance, especially for conversion efficiency. When subjected to a sin wave of exhaust mass flow rate, the efficiency experiences a 15.58 % improvement. This work offers a comprehensive understanding of the dynamic characteristics exhibited by the thermoelectric generator employed for waste heat recovery

ANALYSIS OF DYNAMIC RESPONSE CHARACTERISTICS OF AERONAUTICAL SPIRAL BEVEL GEARS AND OPTINIZATION OF VIBRATION ABSORBING STRUCTURE OF SPOKE PLATE HOLE (MT)

In order to solve the problems of dynamic response and structural vibration suppression of aircraft bevel gear thin-walled spoke plate, an optimal design scheme of damping pass structure was proposed. Taking a certain type of aeronautical spiral bevel gear as an example, the model of spiral bevel gear was established. The natural characteristics of the gear were calculated by Lanczos method, and the frequency margin between the first six natural frequencies and the excitation force was analyzed. The dynamic response characteristics of radial plates with different holes and their suppression effect on vibration transmission were studied by means of modal superposition method. The parameters of radial plate pass structure are optimized by orthogonal experiment design and simulation analysis. The results show that under the condition of the same area and the same number, the vibration responses of triangle, round, pillow and waist shapes decrease in turn. The optimized waist pass can effectively suppress vibration transmission and improve the smoothness of bevel gear transmission

Impacts of Fracture Roughness and Near-Wellbore Tortuosity on Proppant Transport within Hydraulic Fractures

For unconventional reservoir hydraulic fracturing design, a greater fracture length is a prime factor to optimize. However, the core observation results from the Hydraulic Fracturing Test Site (HFTS) show that the propped fractures are far less or shorter than expected, which suggests that the roughness and tortuosity of hydraulic fractures are crucial to sand transport. In this study, a transport model of sands is first built based on experimental measurements on the height and transport velocity of the sand bank in fractures with predetermined width and roughness. The fracture roughness is quantified by using the surface height integral. Then, three-dimensional simulations are conducted with this modified model to further investigate the impact of tortuous fractures on sand transport, from which a regression model is established to estimate the propped length of hydraulic fractures at a certain pumping condition. The experiment results show that the height of the sand bank in rough fractures is 20–50% higher than that in smooth fractures. The height of the sand bank decreases with the reduction in slurry velocity and increases with the increase in sand diameter. Sand sizes do little effect on the transport velocity of the sand bank, but the increase in slurry velocity and sand volume fraction can dramatically enhance the migration velocity of the sand bank. The appearance of tortuous fractures decreases the horizontal velocity of suspended particles and results in a higher sand bank compared with that in straight fractures. When the sand bank reaches equilibrium at the tortuous position, it is easy to produce vortices. So, there is a significant height of sand bank change at the tortuous position. Moreover, sand plugging can occur at the entrance of the fractures, making it difficult for the sand to transport deep into fractures. This study explains why the propped length of fractures in HFTS is short and provides a regression model that can be easily embedded in the fracturing simulation to quickly calculate dimensions of the propped fractures network to predict the length and height of propped fractures during fracturing

STRENGTH TEST AND RELIABILITY EVALUATION OF 20CRNIMO MATERIAL (MT)

Low carbon alloy steel 20CrNiMo is a kind of high strength surface hardening material which was commonly used as high-quality gears. After surface nitriding, carburizing or carbonitriding quenching treatment, it has good tooth surface hardness and tooth root toughness. According to the relevant national standards, a number of material test bars had been designed and carried out, the tensile strength and tensile fatigue strength date of material had been obtained. The lognormal distribution and two parameters Weibull distribution were used to fit and test the testing data, and the R-S-N curves of materials with the different confidence levels were obtained by calculating the probability distribution function. The fatigue life data of the material was more suitable for the lognormal distribution