• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2009.11a
• /
• pp.107-110
• /
• 2009

A basic design for a Technical Development Model (TDM) of liquid oxygen lines from the turbopump exit to the oxidizer valves of the combustion chamber and the gas generator was conducted to develop a turbopump-fed liquid rocket engine. The TDM is composed of straight lines, elbows, bellows, a branch, an orifice, flanges and a heat insulator. Materials were determined by consideration of operation conditions, weight constraint and manufacturing procedures. The size and the location of each component were determined by flow analysis of the required flowrate and the pressure loss. Basic designs of the components were conducted by consideration of the operating temperature and the maximum expectation operating pressure. The safety factors were evaluated by structural analysis of design of each component.

• Journal of Applied Reliability
• /
• v.11 no.2
• /
• pp.177-186
• /
• 2011

Traditionally, one uses a method of straight-line recognition to evaluate quality of product or service. One can satisfy with the product or service if their physical requirement of are met some criterions and can not satisfy them if their physical requirement are not met. Kano, et al(1984) introduce two dimensional Quality model to evaluate quality of product or service. They classify Quality Characteristic of product and service to three categories; satisfying quality, attractive quality, expected quality. In this paper, 17 evaluation features in 6 categories of smart-card are obtained from Focus-interview and Brainstorming and classified into 3 categories of quality model by Kano's two dimensional method. This classification is expected to provide a guideline for evaluation of smart-card.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.59 no.6
• /
• pp.81-87
• /
• 2017

The total area of domestic reclaimed lands is 54,379 ha, and among these, 30,394 ha can be agriculturally available. To increase an agricultural availability of reclaimed land, controlled horticultural products that can be highly profitable have come to the fore. However, as being characteristically concerning, when original glasshouse is intactly applied in reclaimed land, it is unsafe on account of ground subsidence and, even if ground were reinforced, it has a problem by high cost. So a new greenhouse model would be necessary taking into account not only cost-efficiency but also safety with relatively light-weight one. Before this, this paper estimated acceptance rate of controlled horticultural complexes in reclaimed land and new greenhouse model for 414 farmers. The annual rental fee is 129,712,500 won/ha, considering the interest rate (2.5 %) of the investment, the depreciation cost of the facilities (straight line depreciation method, 20 years of service life estimated), and government subsidy rate (50 %) which resulted in a sufficient number of intended tenants with the acceptance rate of 0.33. The results of this paper may contribute to the government's policies for reclaimed land.

• Ocean Systems Engineering
• /
• v.1 no.4
• /
• pp.297-315
• /
• 2011

New applications of streamlined Autonomous Underwater Vehicles require an AUV capable of completing missions with both high-speed straight-line runs and slow maneuvers or station keeping tasks. At low, or zero, forward speeds, the AUV's control surfaces become ineffective. To improve an AUV's low speed maneuverability, while maintaining a low drag profile, through-body tunnel thrusters have become a popular addition to modern AUV systems. The effect of forward vehicle motion and sideslip on these types of thrusters is not well understood. In order to characterize these effects and to adapt existing tunnel thruster models to include them, an experimental system was constructed. This system includes a transverse tunnel thruster mounted in a streamlined AUV. A 6-axis load cell mounted internally was used to measure the thrust directly. The AUV was mounted in Memorial University of Newfoundland's tow tank, and several tests were run to characterize the effect of vehicle motion on the transient and steady state thruster performance. Finally, a thruster model was modified to include these effects.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2000.10a
• /
• pp.78-81
• /
• 2000

In this study the plasic flow before welding stage in the cahamber is analyzed by FEM and experiments during the porthole extrusion process. The analysis is concerned with plastic flow in the port and welding chamber of rectangular hollow section extrusion through the porthole die with mandrell. Numerical simulation by finite element code to investigate the plastic flow is discussed for both tapered inlet and straight inlet chamber. To visualize the flow in extrusion process split dies and punches are designed and manufactred by wire EDM. Experiments are carried out by using the plasticine as a model material at room temperature. The theoretical predictions are reasonable agreements with experimental results in the welding lines and the deformed profiles.

• 제어로봇시스템학회:학술대회논문집
• /
• 1989.10a
• /
• pp.615-620
• /
• 1989

Recently industrial robots are often used together with positioners to enhance the system performance for arc welding. In this paper, the redundancy control method is proposed for the robot-positioner system which is modeled as one kinematic model of 7 degrees of freedom. Also, the manipulability measure based on the Jocobian matrix is utilized to visualize the distribution of manipulability in a given section of the working space. An algorithm for the manipulability maximazation in a given task is developed and applied to the robot and positioner system. The simulation results are given in the case of straight line following.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.20 no.12
• /
• pp.1216-1222
• /
• 2010

Based on the MacDonald's analytic model for the diffracted sound field of a semi-infinite noise barrier, computer simulations were performed for various positions of error microphones for an active noise barrier system. The simulation process also included the effects of floor reflections on both sides of the barrier. The results were also compared with Niu's simulation results and showed a straight line arrangement of sensors and actuators, in the order of primary source, secondary source and error microphone is better than over the top arrangement of the error microphones.

• Journal of the Korean Society for Precision Engineering
• /
• v.18 no.10
• /
• pp.93-100
• /
• 2001

The analysis and control of a new type unsymmetrical slotted self-bearing step motor for small angle control is presented. The motor actuator is used for both motor and bearing functionality without any additional coil windings or electromagnets for bearing functionality. A circular-arc, straight-line permeance model for the fringing effect is presented. An unsymmetrical slotted self-bearing step motor layout and control algorithm are described. A new control current generation method using the electromagnets layout geometry, which needs no additional current for bearing functionality, is proposed. As the result of this analysis the fringing effect largely influences on the system characteristics. especially in torque. Even if the bearing functionality is added into the motor functionality, it is shown that the magnitude of torque is not changed.

• Proceedings of the KSRS Conference
• /
• 1998.09a
• /
• pp.159-162
• /
• 1998

Land cover and land use classification on a huge scale, e.g. national or continental scale, has become more and more important because environmental researches need land cover: And land use data on such scales. We developed a crop field extraction method, which is one of the steps in our land cover classification system for a huge area. Firstly, a crop field model is defined to characterize "crop field" in terms of NDVI value and textual information Textual information is represented by the density of straight lines which are extracted by wavelet transform. Secondly, candidates of NDVI threshold value are determined by "scale-space filtering" method. The most appropriate threshold value among the candidates is determined by evaluating the line density of the area extracted by the threshold value. Finally, the crop field is extracted by applying level slicing to Landsat TM image with the threshold value determined above. The experiment demonstrates that the extracted area by this method coincides very well with the one extracted by visual interpretation.

• International Journal of Automotive Technology
• /
• v.7 no.2
• /
• pp.187-193
• /
• 2006

When emergency evasion during running is required, a driver sometimes causes a vehicle to drift, that is, a condition in which the rear wheels skid due to rapid steering. Under such conditions, the vehicle enters a very unstable state and often becomes uncontrollable. An unstable state of the vehicle induced by rapid steering was simulated and the effect of differential steering assistance was examined. Results indicate that, in emergency evasion while cornering and during which the vehicle begins to drift, unstable behavior like spins can be avoided by differential steering assistance and both the stability and control of the vehicle is improved remarkably. In addition, reduction of overshoot during spin evasion by the differential steering assistance has been shown to enable the vehicle to return to a state of stability in a short time in emergency evasion during straight-line running. Moreover, the effectiveness of differential steering assistance during emergency evasion was confirmed using a driving simulator.