• Aerospace Engineering and Technology
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• v.3 no.1
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• pp.277-286
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• 2004

In this study, summary of past tilt-rotor concept development presented, and based on that, major pros and cons of tilt-rotor technology compared to other air-vehicle concept was presented. Also presented were major design features, considerations and sizing constraints of tilt-rotor configuration implemented to the development of Smart UAV. It is hoped that this paper be served to understand the tilt-rotor air-vehicle design and development.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.8
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• pp.50-55
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• 2005

An advanced method of Relaxed Static Stability (RSS) is utilized for improving the aerodynamic performance of modern version supersonic jet fighter aircraft. The laws of flight control system utilize RSS criteria in both longitudinal and lateral-directional axes to achieve performance enhancements. Particularly, the design of longitudinal control laws for utilizing RSS methods greatly affects the performance of the aircraft in Air-to-Air Tracking and Air-to-Ground modes, which improves weapon delivery. In the area of Air-to-Air Tracking, the development of longitudinal control laws aids in the fine tracking and gross acquisition of other aircraft. This paper proposes that new concept of longitudinal control law introduce in order to improve fine tracking performance in air-to-air tracking maneuver. Result of HQS pilot simulation and flight test, fine tracking performance improve without degradation of gross acquisition when new concept of control law is applied.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10b
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• pp.456-461
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• 1993

In this paper, a new guidance law for a short-range air-to-air missile with constant thrust is presented. It is essentially based on the concept of proportional navigation. First, the theoretical guidance law is derived. Then, we show the technique for practical implementation of the guidance law. By a computer simulation, it is shown that the new guidance law gives better performance than the conventional proportional navigation.

• Journal of the Korean Society of Combustion
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• v.15 no.4
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• pp.1-8
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• 2010

Mild combustion is considered as a promising combustion technology for energy saving and low emission of combustion product gases. In this paper, the controllability of reaction region in mild combustion is examined by using co-axial air nozzle. For this purpose, numerical approach is carried out. Propane is considered for fuel and air is considered for oxidizer and the temperature of air is assumed 900K slightly higher than auto ignition temperature of propane. But unlike main air, the atmospheric condition of co-axial air is considered. Various cases are conducted to verify the characteristics of Co-Axial air burner configuration. The use of coaxial air can affect reaction region. These modification help the mixing between fuel and oxidizer. Then, reaction region is reduced compare to normal burner configuration. The enhancement of main air momentum also affects on temperature uniformity and reaction region. The eddy dissipation concept turbulence/chemistry interaction model is used with two step of global chemical reaction model.

• Journal of Advanced Navigation Technology
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• v.28 no.2
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• pp.201-209
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• 2024

This study investigates the operational facets of low-density urban air mobility (UAM) from an airline's perspective amid burgeoning concerns about urban congestion in megacities. UAM, employing electric vertical takeoff and landing (eVTOL) technology, emerges as a potential remedy to the challenges of traffic gridlock and environmental degradation. As the UAM market progresses from initial stages to maturity, tailored traffic control systems become paramount. Focused on the context of low-density environments during UAM's inception, this research scrutinizes operational frameworks, essential infrastructure, and likely scenarios. It aims to bolster the safety and efficiency of UAM operations by delving into the specifics of traffic control concepts designed for these unique settings. The study seeks to significantly contribute to optimizing UAM's initial phases, providing insights into crucial operational dynamics for a smoother integration of urban air mobility into contemporary urban landscapes.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.81-82
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• 2006

Conveyor-type transporters have been widely used as a typical delivery system of semi-conductor, FPD and other IT-related products. However, as the IT-product is getting larger in size and higher in resolution, several problems are caused by mechanical contacts between the transporter and target object. In this context, recently, lots of efforts are being devoted for development of various contact-free handling systems to get rid of deffets and oil contaminations. The objectives of this paper are to characterize suspension mechanisms and to investigate air flow effects on air levitation transport system. For this purpose, a series of CFD analyses were carried out and the simulation data showed a good agreement with the corresponding experimental ones. It is anticipated that the promising result can be used as a basis for concept design of the transport system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.2
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• pp.278-284
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• 2009

The global force and interaction body force density were evaluated in permanent magnets by using the virtual air-gap scheme incorporating the finite-element method. Until now, the virtual air-gap concept has been successfully applied to calculate a contact force and a body force density in soft magnetic materials. These force calculating methods have been called as generalized methods such as the generalized magnetic charge force density method, the generalized magnetizing current force density method, and the generalized Kelvin force density method. For permanent magnets, however, there have been few research works on a contact force and a force density field. Unlike the conventional force calculating methods resulting in surface force densities, the generalized methods are novel methods of evaluating body force density. These generalized methods yield the actual total force, but their distributions have an irregularity, which seems to be random distributions of body force density. Inside permanent magnets, however, a smooth pattern was obtained in the interaction body force density, which represents the interacting force field among magnetic materials. To evaluate the interaction body force density, the intrinsic force density should be withdrawn from the total force density. Several analysis models with permanent magnets were tested to verify the proposed methods evaluating the interaction body force density and the contact force, in which the permanent magnet contacts with a soft magnetic material.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.5
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• pp.640-648
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• 1998

A numerical study has been conducted to investigate the effect of inflow supply air temperature and velocity on ventilation effectiveness in an underfloor air conditioning space. A low Reynolds number k-$\varepsilon$ model is implemented to calculate steady state turbulent velocity distributions. A step-down injection method is used to calculate local and room mean ages from transient concentrations based on the concept of the age of air. Results show that there is a significant effect of Archimedes number on ventilation effectiveness especially for cooling conditions. Reynolds number shows relatively minor effect on velocity distribution and ventilation effectiveness especially for isothermal and heating conditions. It can be concluded that underfloor air conditioning system provides good ventilation characteristics for cooling conditions because of temperature stratification in the space.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.4
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• pp.349-358
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• 2015

The research and development trend of Trajectory-based Operations(TBO), which is considered as a key concept of future Air Traffic Management(ATM), is presented in this paper. The operational concepts of TBO in ASBU(Aviation System Block Upgrade) from ICAO(International Civil Aviation Organization) have been summarized, and the detailed operational concepts and procedures, which can be realized in the near future, are described through the investigations of operational concept development and related research/development activities of TBO in USA and Europe. The technical enablers, which have been identified based on understanding of TBO operational concepts, are introduced, and related research/development status of each technical enabler has been presented.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.04a
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• pp.155-157
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• 2000

In modem buildings, the concept of open-space plan gets more acceptance as it supports more flexibility for the internal space design. This open-space can be easily subdivided by internal partitioning to provide each individual working zone. Although the partitioning forms each physical working zone, its indoor environment could be different Iron what the occupants require. Especially the air movement and contaminant spread in each working zone could be blocked or distorted by the partitioning, which may produce unexpected change in ventilation performance designed. (omitted)