PRESSURE DISTRIBUTION DUE TO STERN TAB DEFLECTION AT MODEL SCALE

Trim tabs form an important part of motion control systems on high-speed watercraft. By altering the pitch angle, significant improvements in propulsion efficiency can be achieved by reducing overall resistance. For a ship in heavy seas, trim tabs can also be used to reduce structural loads by changing the vessel orientation in response to encountered waves. In this study, trials have been conducted in the University of Tasmania hydraulics laboratory using a closed- circuit water tunnel to measure model scale trim tab forces. The model scale system replicates the stern tabs on the full- scale INCAT Tasmania 112 m high-speed wave-piercer catamaran. The model was designed for total lift force measurement and pressure tappings allowed for pressures to be measured at fixed locations on the underside of the hull and tab. This investigation examines the pressures at various flow velocities and tab deflection angles for the case of horizontal vessel trim. A simplified two-dimensional CFD model of the hull and tab has also been analysed using ANSYS CFX software. The results of model tests and CFD indicate that the maximum pressure occurs in the vicinity of the tab hinge and that the pressure distribution is long-tailed in the direction forward of the hinge. This accounts for the location of the resultant lift force, which is found to act forward of the tab hinge.

Incorporating Robustness to Imaging Physics into Radiomic Feature Selection for Breast Cancer Risk Estimation

Digital mammography has seen an explosion in the number of radiomic features used for risk-assessment modeling. However, having more features is not necessarily beneficial, as some features may be overly sensitive to imaging physics (contrast, noise, and image sharpness). To measure the effects of imaging physics, we analyzed the feature variation across imaging acquisition settings (kV, mAs) using an anthropomorphic phantom. We also analyzed the intra-woman variation (IWV), a measure of how much a feature varies between breasts with similar parenchymal patterns—a woman’s left and right breasts. From 341 features, we identified “robust” features that minimized the effects of imaging physics and IWV. We also investigated whether robust features offered better case-control classification in an independent data set of 575 images, all with an overall BI-RADS® assessment of 1 (negative) or 2 (benign); 115 images (cases) were of women who developed cancer at least one year after that screening image, matched to 460 controls. We modeled cancer occurrence via logistic regression, using cross‑validated area under the receiver-operating-characteristic curve (AUC) to measure model performance. Models using features from the most-robust quartile of features yielded an AUC = 0.59, versus 0.54 for the least-robust, with p < 0.005 for the difference among the quartiles.

Research on interactive color design method of cultural creative product driven by group consensus

Aiming at assisting the color design of cultural creative product and outputting color schemes that correspond to multi-user image preference effectively, an interactive color design method driven by group consensus was proposed in this paper. Firstly, the triangular fuzzy number was used to quantitatively descript users' image preference and a consensus degree model of group users' image preference was constructed. By studying the process and basic principles of interactive genetic algorithms, the interactive evolution operation for cultural creative product color design was then implemented based on the group consistency of decision-making combined with the triangular fuzzy number, which can help generate cultural creative product color schemes that satisfy group consensus and satisfaction. Next, the color aesthetic measure model was used to rank and select the final product color design schemes. Finally, taking the color design of terracotta warriors' statue as an example, it is verified that the proposed method can effectively integrate the image preference of group users, and assist designers to better conduct cultural creative product color design with the consistent results of multi-user decisions.

Exploring the Effect of COVID-19 on Airline Environmental Efficiency Through an Interval Epsilon-based Measure Model

COVID-19 has dealt an unprecedented blow to the aviation industry since 2020. This paper applies the Interval Epsilon-Based Measure (IEBM) model to evaluate the optimal quarterly environmental efficiency of 14 global airlines of passenger and cargo subsystems during 2018-2020. Then, the Time Series Prediction method is applied to forecast the interval data of inputs and outputs from 2021 to 2022 and calculate the quarterly efficiency. Thus, the future development trends of airlines can be predicted. Furthermore, the results accord with reality can verify the credibility and accuracy of the model. Furthermore, the results show that: 1. COVID-19 has hit the passenger subsystem harder, while the freight subsystem has become more efficient; 2. The efficiency of the freight subsystem has inevitably declined in the post-epidemic era; 3. Therefore, the airlines will have a “√” shaped recovery curve in the next few years.