• Fashion & Textile Research Journal
• /
• v.11 no.2
• /
• pp.301-307
• /
• 2009

The purpose of this study is to investigate the problem and complaint of current flight suit derived with the questionnaires. The survey was carried out to the 137 aviators in Army Aviation School from April to May, 2007. The questionnaires were composed of personal characteristics, usage characteristics, wearing characteristics and free comments. Regard to the questionnaires of usage characteristics, they wore the flight suit over 6 hours a day and over 5 days a week. For wearing convenience item in usage characteristics it was revealed that fitness, ease and the location of pocket were not proper, Also, it showed that the material characteristics(e.g. insulation, absorption, and sensation) for flight suit was not proper. Regard to the questionnaire of wearing characteristics, the most inconvenient part is crotch as the answer on the question of "unfitting part in size" and "inconvenient part when wearing". Free comments for the improvement requests are various size, material, stitch strengthening, pattern modifying, and accessories.

• Proceedings of the KSME Conference
• /
• 2004.11a
• /
• pp.1586-1591
• /
• 2004

Flow visualization experiments have been performed to investigate the effects of phase lag, reduced frequency qualitatively by examining wake pattern on a dragonfly type wing. The model was built with a scaled-up, flapping wings, composed of paired wings with fore- and hindwing in tandem, that mimicked the wing form of a dragonfly. The present study was conducted by using the smoke-wire technique, and an electronic device was mounted to find the exact positional angle of wing below the tandem wings, which amplitude is ranged from $-16.5^{\circ}$ to $+22.8^{\circ}$. Phase lag applied on the wings is $0^{\circ}$, $90^{\circ}$, $180^{\circ}$ and $270^{\circ}$. The reduced frequency is 0.15, 0.3 and 0.45 to investigate the effect of reduced frequency. It is inferred through observed wake pattern that the phase lag clearly plays an important role in the wake structures and in the flight efficiency as changing the interaction of wings. The reduced frequency also is closely related to wake pattern and determines flight efficiency.

• Journal of agriculture & life science
• /
• v.52 no.6
• /
• pp.111-125
• /
• 2018

In this study, we evaluated the uniformity of deposition rate and particle size distributions of the variable rate application technique using the unmanned rotorcraft by measuring the spray pattern according to path location in the range of spraying flight. The coefficient of variation (CV) of the lateral coverage rate for the overlapped distribution with the spray swath of 3.6 m in both guidance and auto-pilot flight modes maintaining constant flight speed was about 30% and the CV of the coverage rate by the flight path location was extremely small. Therefore, it was assessed that the variable rate application technology compensating for the variation of ground speed was superior in terms of spray uniformity. In addition, the droplet size distributions in both volume median diameter(VMD) and number median diameter(NMD) were adequate for aerial application and uniform in terms of lateral distribution. Thereafter, we intend to contribute to a precise application on small-scaled fields using the unmanned agricultural rotorcraft by the variable rate application.

• Journal of Aerospace System Engineering
• /
• v.14 no.5
• /
• pp.122-129
• /
• 2020

Surion is required to install radios (U/VHF-AM, VHF-FM) capable of omni-directional communication. Therefore, this paper demonstrates the antenna performance test for the installation of the Surion communication antenna and the selection of optimal location. A simulation pattern analysis was performed employing the antenna, and a coupling test was performed by creating a new evaluation criterion. In addition, the results of the pattern flight test conducted at the previously suggested 1:20 turn and separation distance ratio were observed to be normal. However, the occurrence of voice cutoff was noted in the long-distance flight test. Therefore, in this paper, 1:300 (15 NM) is proposed as a new optimal ratio for predicting the long-distance flight test results in advance. Finally, the effectiveness of the proposed evaluation criteria was verified through long-distance flight tests. Consequently, it is expected to reduce the development schedule and cost by reducing the trial and error of the performance test for the Surion model. Also, the results of this study are expected to be used as standards for the installation of communication antenna and quality tests for other helicopters.

• Analytical Science and Technology
• /
• v.8 no.4
• /
• pp.715-722
• /
• 1995

The structural characterization for series of polyesters has been done by time-of-flight secondary ion mass spectrometry (TOF-SIMS). Polymer fragments and intact oligomers composed of large numbers of repeat units have been investigated. Transesterification of polyesters in trifluoroacetic acid (TFA) and chlorodifluoroacetic acid (CFA) was monitored and reaction products were identified using TOF-SIMS. The shapes and intensities of clusters in transesterification spectra show good agreement with the theoretical isotope pattern. TOF-SIMS spectra were used to obtain information about the progress of the transesterification reaction.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.31 no.6
• /
• pp.96-101
• /
• 2003

Korea Sounding Rocket(KSR)-III onboard telemetry system has acquired various data from subsystems and sensors in the rocket, and radiated PCM/FM data using two S-band antennas during the flight. Simultaneously， it is necessary that the ground receiving systems track the rocket, and receive and decode telemetry data. Also post processed telemetry data are needed to be broadcasted on ethernet network in real time. Range safety display system displays flight trajectory using telemetry data in mission control center, and so flight manager makes a decision for flight termination from the trajectory This paper describes operating technique about telemetry reception, the development for the realtime data processing system, and the results for telemetering reception on fight test. We telemetered, processed, and broadcasted numerous telemetry data during the flight test successfully.

• Journal of Institute of Convergence Technology
• /
• v.10 no.1
• /
• pp.1-5
• /
• 2020

The wake shapes behind wings in formation flight are very important to the aerodynamics and performances of aircrafts. In the present study, a discrete vortex methood is extended to handle the wake rollups behind multiple wings. It was found that the relative distance between the wings and the rotational direction of the wingtip vortices have significant effect on the movement of the wingtip vortices. When the wings are close to each other, the wingtip vortices moved faster than the wings of large relative distances. The vortex pair of opposite signs generated from each wingtip has an effect of moving the wingtip vortices upward. The relative height between the wings has an effect of moving the wingtips along the centerline of each vortex. The wakeshape behind multiple wings is a function of the relative distances and thus is dependent on the configuration of the formation flight. In the futhre, a study on the vortex movement pattern will be studied.

• 한국항공운항학회:학술대회논문집
• /
• 2016.05a
• /
• pp.269-275
• /
• 2016

This paper considers the arrival, airport and departure capacity as a whole, through which, the network effect between airports is fully emphasized, the flight action is coordinated, and the flight demand pattern is reasonably assigned. The optimization problem of flight queues in multi-airport is studied in detail; the mathematical model of multi-airport opening non-real time flow management in terminal area is established, and related problems such as the parameters, the simplification and the solving of the model are discussed in detail to some extent. Appropriate decision making variables are taken to make the multi-airport network system linear 0-1 integer programming model, thus, the solving of the model is available and the central flow management is realized. The heuristic implicit enumeration presented in this paper can effectively solve this kind of problems. Through the simulation of some airports network system, we not only validate the algorithm presented in this paper, but also give a deep analysis of the results, which would produce reference for later practicable use. The simulation proves that this algorithm offers a good way to settle the problem of multi-airport flight queue optimization in air traffic management automation system in terminal area.

• Journal of Contemporary Eastern Asia
• /
• v.4 no.1
• /
• pp.1-7
• /
• 2005

In this paper uses Kaname Akamatsu's 'Flying Geese' model to analyse Japan's role in East Asian integration. Japan made the first attempt to lead Asian countries before the Second World War. At that time, the Japanese Government embarked on a brutally expansionist policy the result of which was creation of the first gaggle of 'flying geese' under the name of the 'Greater East Asia Co-Prosperity Sphere.' During the 'flight' Japan was forcefully imposing its own ideals and values on the rest of the 'gaggle.' At the same time, the Japanese Government assumed hostile attitude toward Western countries. Japan's defeat in the Second World War signified the end of flight for the first 'flying geese' gaggle. After the war, Japan made another attempt at regional integration. This time it was done through establishing a production network in East Asia. Thus the second gaggle of 'flying geese' came into existence. During the flight of the 'second gaggle' of geese, Japan was fostering good ties with Western countries as well, especially the United States. However, some leaders of the 'second gaggle's' member-countries emboldened by their countries' economic success proclaimed that future belongs to Asia and put forward the 'Asian values' argument. The Asian economic crisis of 1997 interrupted the flight of the 'second gaggle' and effectively put an end to the 'Asian values' debate. It is interesting to note that some elements of the 'Asian values' argument resembled ultranationalist discourse that had been dominant in Japan before and during the Second World War. This paper compares historical patterns of East Asian regional integration and highlights future challenges for Japan's Asia policy.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.37 no.8
• /
• pp.729-736
• /
• 2009

In order to understand flow characteristics and flight mechanism of hummingbird's flapping flight, two-dimensional numerical analysis is carried out on the flapping motion of hummingbird, Selasphorus rufus. Hummingbird's flapping wing motion is realistically modeled from wind tunnel experimental data to perform numerical analysis. Numerical simulation shows that, as freestream velocity changes, wing trajectory is also adjusted and it substantially affects lift and thrust generation mechanism. According to this tendency, flight domain is separated as "low speed" and "high speed" regime, and each flight domain is studied for physical understanding. As a result, the lift generation during downstroke can be explained by the well-known effects, such as leading edge vortex effect, delayed stall, wake capture and so on. In addition, the lift generation during upstroke, the unique character of hummingbird, is also examined by detailed flow analysis. The thrust generation mechanism is investigated by examining the hummingbird's wing bone structure, vortex generation pattern and the resulting pressure gradient.