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The face measurements of KAF pilots were collected and compared with those of Korean civilians and USAF personnel. The distinct facial features of the populations identified in this study are applicable to custom design of an oxygen mask for prevention of excessive pressure and oxygen leakage.

Since random early detection (RED) was proposed in 1993, many active queue management (AQM) algorithms have been proposed to support better end-to-end Transmission Control Protocol (TCP) congestion control. In this article, the authors introduce and analyze a feedback control model of the TCP/AQM dynamics. Then they suggest the concept of an AQM algorithm that can detect and avoid congestion proactively. Finally, they propose the proportional-integral (PI) proportional-derivative (PD) controller using proportional-integral-derivative (PID) feedback control to overcome the reactive control behavior of existing AQM proposals. The PI-PD controller is able to provide proactive congestion avoidance and control using an adaptive congestion indicator and a control function. A comparative simulation study under a variety of network environments shows that the PI-PD controller outperforms RED and the PI controller in terms of the queue length dynamics, the packet loss rates, and the link utilization.

The present study developed a virtual fit assessment (VFA) method to design an oxygen mask which fits Korean Air Force (KAF) pilots. The VFA method used 3D face scan data of 336 KAF pilots to find the most proper shape of an oxygen mask for KAF pilots. The oxygen mask design revised in the study showed a 27% design improvement effect on average in terms of fit evaluated by the VFA method. Additionally, the present study evaluated the revised oxygen mask prototypes with 88 KAF pilots to experimentally verify the design improvement effect in terms of discomfort, pressure, and suitability for military equipment (slippage and stability in flight-like situations). The discomfort of the revised mask was 33 ~ 56% lower on average than the existing oxygen mask. In terms of the pressure, the revised mask showed 11 ~ 33% of improvement on average compared to the existing mask. Furthermore, on high gravity situation, the slippage distance of the revised mask was 24% shorter on average than the existing mask. The proposed VFA method can be applied to the design and evaluation of wearable products that require an ergonomically better fit for a target population.

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