• International Journal of Concrete Structures and Materials
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• v.2 no.2
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• pp.153-160
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• 2008

Fracture of prestressed concrete beams is studied with a novel and robust three-dimensional meshfree method. The meshfree method describes the crack as a set of cohesive crack segments and avoids the representation of the crack surface. It is ideally suited for a large number of cracks. The crack is modeled by splitting particles into two particles on opposite sides of the crack segment and the shape functions of neighboring particles are modified in a way the discontinuous displacement field is captured appropriately. A simple, robust and efficient way to determine, on which side adjacent particles of the corresponding crack segment lies, is proposed. We will show that the method does not show any "mesh" orientation bias and captures complicated failure patterns of experimental data well.

• Journal of IKEEE
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• v.17 no.4
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• pp.393-397
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• 2013

This paper introduces the T/RX combined compact active channel module which is a key unit of the active phased array antenna(APAA) system. This module is mainly compoased of two parts for TX and RX fabricated on both sides of the active module for size reduction. The TX-part is primarily composed of a 3-stage amplifier, a microstrip phase shifter, a thermal compensation and a power detection circuit. The RX-part is composed of LNAs a microstrip phase shifter and BPFs for TX power rejection. Using the proposed design structure we can realized a compact active channel module having high performance.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.181.2-181
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• 2001

Stereo PACS (Picture Archiving and Communication System) is not available yet because of some limitations of medical stereo image software and viewing devices. As a stereo PACS viewer, we designed two functions. One is selecting and viewing a multiplexed stereo image directly, and the other is selecting a stereo pair image (left and right sides both) and merging the stereo pair image into a multiplexed image in software. For the medical image compression of 3-D stereo endoscopic images, we used JPEG and Wavelet compression and to determine an acceptable compression rate using PSNR (Peak Signal-to-Noise Ratio). As a result, we got the conclusion that medically acceptable image compression rate should have the PSNR of above about 40[dB] (JPEG (5:1), Wavelet (10:1)).

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.341-345
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• 2001

New technoloty called microcellular foaming process was developed at MIT in 1980's. Although it has many good things, it could not be used it all sides of manufacturing plastics. Because it takes a long time for making foamed goods. So microcellular foaming injection molding process appeared to solve this problem. The first purpose of this research is to measure the impact strength as foaming magnitude of microcellular foamed plastics. There are two methods such as batch process and microcellular foaming injection molding process in making foamed plastics. According to the experimental data, the impact strength of each specimen was measured to find out the influence of foaming magnitude of microcellular foamed plastics.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.3
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• pp.389-395
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• 2006

The fluid force reduction of a square prism having fences on the corner was studied by the measuring the drag and lift acting on the prism and by the visualization experiment of the flow around the prism. The height of the fence was 10% of the square width and the range of Reynolds number considered was from $Re=0.9{\times}104$ to $Re=2.1{\times}104$. The drag of the prism was reduced about 6.8% and the amplitude of the lift was reduced by attaching two normal fences on the rear corners of the prism. In this case, the separated flow at the front corners was reattached on the upper and lower sides of the prism and the vortex streets at the wake region were appeared more slowly than that of the prototype prism.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.5
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• pp.14-20
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• 2020

In this study, the overall states of the airflow when a truck with or without side pairing is driven at a maximum speed of 90 km/h, regulated by domestic law, were investigated through computational fluid dynamics numerical analysis. All the tested models showed that the airflow went under the truck body; specifically, the air did not flow along the underside to the rear of the truck but through the sides of its underside. The drag with the drag coefficient at model 3 was clearly higher than those for the other two models. The results of this study could help to improve the truck performance by reducing its resistance against the air flown from it in driving itself.

• Advances in Energy Research
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• v.2 no.1
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• pp.47-59
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• 2014

Back-to-back STATCOM configuration is an extension of STATCOM in which the reactive power at two-sides and the real power flow through the DC link can be controlled concurrently and independently. This flexible operation brings many advantages to the micro-grids, distributed generation based systems, and deregulated power systems. In this paper, the dynamic control characteristics of the back-to-back STATCOM is investigated by simulating the detailed converter-level model of the converters in PSCAD. Various case studies in a single-machine test system are studied to present that the real power control feature of the BtB-STATCOM, even with a simple controller design, can enhance the transient stability of the machine under different fault scenarios.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.19 no.3 s.31
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• pp.232-236
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• 2006

Objectives : Strabismus refers to the oculomotor muscles imbalance that results from improper alignment of the visual axes of the two eyes. It may be divided into paralytic and nonparalytic strabismus. Paralytic strabismus is primarily result from neurologic problem and nonparalytic strabismus is more strictly opthalmologic problem. At first we used this method(electroacupuncture at oculomotor muscles) and gained good recoveries for adult paralytic strabismus cases or Miller-Fisher syndrome, and I tried to know the effective and safety for children cases. Methods : We treated the case by using the electroacupuncture at paralytic oculomator muscles. The case was treated almost daily and every treatment was enforced 10 minutes. We use the PG-306 electra-acupuncture products(Suzki Iryoki Co. Japan) and apply the low consequence wave of I-8Hz Results : We found that the case was recovered perfectly in short term and appealed any sides effect or compliant. So I try to apply this treatment in many children cases and make the treating protocol for them.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.504-511
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• 2001

In this research, we developed a computer program that designs a centrifugal impeller and diffuser, and predicts the far-field noise from the impeller. To design the impeller optimally, the TEIS model, which was originally developed by Japkise(1985), and the mean-line analysis are combined to predict the performance and design the optimal impeller simultaneously. The geometric configurations are provided by a GUI software (iDesignComp). The noise from impeller can be computed by the rapid loading procedure, which generates a surface between two blades and calculates the pressure distributions on the suction and pressure sides. The steady loading noise is computed by the rotating dipole source distribution via Ffowcs Williams & Hawkings equation.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.1
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• pp.104-109
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• 2016

The noncontact vibration exciter system using the electro-magnet for a thin plate is studied in this paper. Based on the Euler-Bernoulli beam theory, the equation of motion of thin plate is derived. The main purpose of this experiment is to match the input-frequency and response frequency of thin plate. The test equipment is configured to vibrate on both sides of the thin plate using the electro-magnet. Two frequencies(input frequency and response frequency) in our experiments show very good agreement. This study results will contribute to basic investigate of an alternative air-knife system for the steel industry.