This research proposes the reliability analysis for the resilient operation of a smart antenna for radio astronomy mission considering the function recovery after failure of some actuators. The smart reflector system consists of a primary reflector and a deformable sub-reflector installed with actuators that adaptively adjust the surface shape of the sub-reflector to correct the adverse effect of the primary reflector distortion. The resilient operation proposed in the previous study aims to recover the function of the antenna system by using the survived actuators after failure of some actuators. It was found that the resilient operation succeeds in the function recovery in some cases but not in others. This study first proposes the operating rate to quantitatively evaluate the effect of the resilient operation that considers the observation condition and combinations of failed actuators. Then, the reliability analysis is formulated to consider the proposed operating rate and the failure probability of actuator. Through numerical examples, validity of the proposed method is demonstrated to quantify the reliability for the resilient operation of the smart reflector. Finally, the target failure rate of the actuators to satisfy the target reliability of the smart antenna is evaluated.

The Reynolds number (Re) based on the wing chord of an insect wing is less than 10,000. As the insect size decreases to millimeters in length and Reynolds number decreases to double figures or less, gapped wings with hairs called comb wings appear instead of the membrane wings. For example, plume moths and thrips have comb wings. The purpose of this study is to ascertain the aerodynamic characteristics of comb wings in wind tunnel tests at very low Reynolds numbers less than 100. A wind tunnel, which was operated in a lower pressure environment, and a high sensitivity balance system were developed for these measurements. The lift and drag acting on the flat plate and the comb wing were measured at an angle of attack range of -90deg < α < 90deg with 20 ≤ Re ≤ 500. The comb wing performed well equivalent to the flat plate at Re ≦ 20.

Major communication tools for air traffic control (ATC) and management (ATM) is still verbal-based system while digital communication system has been widely used in the other fields. Although some digital communication tools have been gradually and partially employed even in ATC system, digitalization of the communication systems for air traffic control is quite limited which will be promising technologies for enhancing efficiency and safety of ATC/ATM. This paper firstly summarizes the progress and issues of the communication system for ATC/ATM in Japan. Secondly, the demand and capacity balance for digital satellite communication system is analyzed based on the future air traffic demand prediction in Tokyo metropolitan airspace. Finally, the future direction and challenges for developing digital communication infrastructure for ATC/ATM are discussed based on the results of demand and capacity balance.

Estimation of aircraft weight in flight, which is a dominant parameter correlated with its flight performance, was studied. Typical approach for the estimation is to use simple combination of initial weight on ground and fuel consumption in air obtained with fuel tank gauge or by accumulating fuel flow. This approach is insufficient when the flight performance will be estimated as accurate as possible because all available measurements are not utilized. Therefore, forward-backward smoother derived from Kalman filter was applied to the estimation with our revision of the smoother to fuse terminal weight on ground additionally. According to numerical simulations, our method estimated the weight in smaller errors than not only the typical approach but also a fixed-interval smoother, which is used generally for an offline estimation problem. Moreover, application to actual flight data showed that our method improved the estimated standard deviation by approximate 3% at maximum compared to the fixed-interval smoother.