• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.7
• /
• pp.24-31
• /
• 1999

Bulging is a forming method to shape of die cavity by using hydraulic pressure in tube or vessel. Bulging machine and die were developed in order to produce vessel for keeping warm. Bulging machine is a double type with two horizontal cylinders for bulging of two pieces at the same time. The developed die system has one bulging die and two drawing dies for necking at the both ends of tube. The diameter of tube expands by hydraulic pressure in tube. at the same time, thrust at the both ends of tube. pushes tube in the direction of expansion to obtain high expanding rate with no crack. In this study, the bulging properties were investigated to solve tube crack and necking in manufacturing vessel by the combination method of bulging and drawing. As a result, high expanding rate of tube radius without crack, precision necking and high productivity were obtained.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.49 no.10
• /
• pp.473-478
• /
• 2000

A more reliable algorithm for detecting a high impedance fault (HIF) requires voltage and current at the relaying point containing information of HIF characteristics including buildup/shoulder as well as nonlinearity/asymmetry. This paper presents a modeling method of an HIF in a distribution system. In order to do this, the proposed method uses two series time-varying resistances (TVRs) controlled by Transient Analysis of Control Systems (TACS) in EMTP. One TVR is employed for nonlinearity/asymmetry and then the other TVR for buildup/shoulder. The proposed method is implemented in EMTP and thus the voltage and current at the relaying point can be obtained.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.14 no.4
• /
• pp.676-683
• /
• 2011

In this paper, we propose a robust method which can detect and track a high-speed small approaching target in a cluttered environment for Korean Active Protection System. The proposed method uses a temporal and spatial filter, tracking filter to detect and track a single target in consecutive order. And it is comprised of a candidate target detection step, a prior target selection step and a target tracking. Field tests on real infrared image sequences show that the proposed method could stably track a high speed and small target in complex background and target occlusion.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2005.05b
• /
• pp.77-80
• /
• 2005

Lightweight concrete is known for its advantage of reducing the self-weight of the structures, reducing the areas of sectional members as well as making the construction convenient. Thus the construction cost can be saved when applied to structures such as long-span bridge and high rise buildings. However, the lightweight concrete requires specific mix design method that is quite different from the typical concrete, since using the typical mix method would give rise the material segregation as well as lower the strength by the reduced weight of the aggregate. In order to avoid such problems, it is recommended to apply the mix design method of self-compacting concrete for the lightweight concrete. Experimental tests were performed as such compressive strength, dry shrinkage and carbonation of high strength lightweight self-compacting concrete.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.49 no.3
• /
• pp.95-101
• /
• 2000

In this paper, an improved method for magnetic inspection to detect surface of a conductor is presented. The presented method is based on the technique of ECP(Electric Current Perturbation), which is to measure the variation of current flow due to defects with a magnetic sensor. The inspection performance is improved by using high frequency current behaviors in order to concentrate the current near the defect and employing the resonant frequency of a search coil as an operating frequency. By analytical results and experiments of the test specimens, the feasibility of the inspection method is shown.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.64 no.12
• /
• pp.1742-1747
• /
• 2015

An improved transfer alignment method for a strap-down inertial navigation system (SDINS) is presented here. The alignment accuracy in conventional method is vulnerable to the data latency of a Master INS (MINS) in high maneuverable platforms. We propose a time delay compensation equation considering higher-order terms in the attitude measurement equation of the Kalman filter. The equation incorporates additional information including angular rate, angular acceleration and linear acceleration from the MINS. Simulation results show that the transfer alignment accuracy is significantly improved in the high dynamic environment by incorporating the latency compensation technique.

• Journal of the Korean Society for Precision Engineering
• /
• v.21 no.6
• /
• pp.77-83
• /
• 2004

Cutting by a high speed laser cutting machine is one of most effective technologies to improve productivity. This paper has studied to obtain the cutting characteristics and optimal cutting conditions in a high speed feeding type laser cutting machine by Tacuchi method in design of experiments. A Lf(34) orthogonal array is adopted to study the effect of adjustment parameter. The adjustment parameters consist of cutting speed, laser power, laser output duty and assistant gas pressure. And the quality feature is selected as surface roughness of sheet metal. Variance analysis is performed in order to evaluate the effect of adjustment parameters on the quality feature of laser cutting process.

• Journal of Mechanical Science and Technology
• /
• v.19 no.12
• /
• pp.2281-2288
• /
• 2005

Because an injected spray development process consists of impinging and free spray in the diesel engine, it is needed to analyze the impinging spray and free spray, simultaneously, in order to study the diesel spray behavior. To dominate combustion characteristics in diesel engine is interaction between injected fuel and ambient gas, that is, process of mixture formation. Also it is very important to analyze liquid and vapor phases of injected fuel on the investigation of mixing process, respectively and simultaneously. Therefore, in this study, the behavior characteristics of the liquid phase and the vapor phase of diesel spray was studied by using exciplex fluorescence method in high temperature and injection pressure field. Finally, it can be confirmed that the distribution of vapor concentration is more uniform in the case of the high injection than in that of the low injection pressure.

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 1987.04a
• /
• pp.52-55
• /
• 1987

In tihis paper an improved matching method using subtemplate of moving region and 3-step search algorithm is proposed It reduces heavy computational load of the conventional method. The proposed method is applied to an automatic target tracker using high speed 16 bit microprocessor in order to track one moving target in real time. Expericmental results show that the proposed method has better performance over the conventional methodin spite of greately reducing the computational load, even in came complex background.

• 제어로봇시스템학회:학술대회논문집
• /
• 2002.10a
• /
• pp.66.4-66
• /
• 2002

In this paper, coefficient diagram method is applied to a center position controller design of the web. The significant property of this controller is the designer can design the controller simultaneously a good balance of stability, response, and robustness. Manabe's CDM is useless for designing high-order plant. We proposed a modified CDM which can be called as approximated pole placement method. The practicality of the proposed method is shown through computer simulation.