• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.1
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• pp.95-102
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• 2023

This study investigated the structural performance of wire-integrated steel decks with varied lattice end support conditions through finite element analysis. The results indicated that the steel decks with the lattice foots positioned above the supporting structural member have the higher system stiffness compared to the cases with the lattice foots shifted away from the support. It is also observed that the contribution of the end vertical bars on both the system stiffness and the strength is negligible when the lattice foots are located on the support. It is, especially, revealed that the end vertical bars can be eliminated when the lattice foot length is not smaller than 40mm. The ultimate load-carrying capacity of the system is not significantly affected by the lattice end support condition. The failure mode of the system is the top bar buckling at the center of the deck plate, the lattice end buckling, and the combination of both depending of design intention.

• Structural Engineering and Mechanics
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• v.26 no.2
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• pp.211-229
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• 2007

An experimental investigation to determine the transfer length of a seven-wire prestressing strand in different concretes is presented in this paper. A testing technique based on the analysis of bond behaviour by means of measuring the force supported by the prestressing strand on a series of specimens with different embedment lengths has been used. An analytical bond model to calculate the transfer length from an inelastic bond stress distribution along the transfer length has been obtained. A relationship between the plastic bond stress for transfer length and the concrete compressive strength at the time of prestress transfer has been found. An equation to predict the average and both the lower bound and the upper bound values of transfer length is proposed. The experimental results have not only been compared with the theoretical prediction from proposed equations in the literature, but also with experimental results obtained by several researchers.

• Journal of the Korean Magnetics Society
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• v.17 no.2
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• pp.55-59
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• 2007

Co-based amorphous magnetic wire with a diameter of $125{\mu}m$ and a length of 40 mm was used as an inner conductor of a coaxial cable to construct a magnetic sensor. Sensor characteristics was measured up to 3 GHz with applied up to 60 Oe by using network analyzer. Frequency dependence of impedance for this sensor was very close to the impedance resonant pattern of transmission line and 250 MHz was obtained as a 1/4 wavelength without external magnetic field. Large impedance change was measured in the magnetic field range between 0 Oe and 1 Oe, which was influenced by permeability change of magnetic amorphous wire. Because ${\Delta}Z/{\Delta}H$ value of $300{\Omega}/Oe$ was obtained at 0.1 Oe, this coaxial cable with amorphous wire can be useful as a magnetic sensor.

• Archives of Craniofacial Surgery
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• v.12 no.1
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• pp.28-32
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• 2011

Purpose: A cranioremodeling helmet for correcting plagiocephaly was recently developed. However, no discrete objective methods to evaluate how the deformity is being corrected have been developed. We have established an easy and cost-effective method that can be used not only to show the correction process, but can also be used by physicians to assess the degree of plagiocephaly two-dimensionally. Methods: For two-dimensional evaluation, a length of malleable memory wire (2 mm in diameter) resembling "Sun-Wukong's headband" was placed on the patient's head. The wire around the patient's head was positioned on a plane including points 1 cm above the eyebrow and 1 cm above the auricle. The wire was placed on a sheet of paper and the outline was marked using pens of various colors during each visit. The degree of plagiocephaly correction could then be shown to the patient's parents at every consultation. Results: The method established by the present study easily shows the horizontal cross-section transformation of the head, illustrates plagiocephaly correction by the helmet, and shows the degree of correction in a two-dimensional manner. Conclusion: A soft-shell helmet is widely used for correcting plagiocephaly. However, evaluating the effectiveness of the helmet has been determined in a subjective manner, and a more objective method is now in demanded. Our study found that a "Sun-Wukong's headband" wire can accurately measure two-dimensional changes. Future studies will be required to identify landmarks needed for assessing plagiocephaly correction.

• Journal of the Korea Society of Computer and Information
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• v.29 no.1
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• pp.77-84
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• 2024

In this paper, we propose a method for accurately and rapidly detecting defects in wire harnesses by utilizing computer vision to calculate six crucial measurement values: the length of crimped terminals, the dimensions (width) of terminal ends, and the width of crimped sections (wire and core portions). We employ Harris corner detection to locate object positions from two types of data. Additionally, we generate reference points for extracting measurement values by utilizing features specific to each measurement area and exploiting the contrast in shading between the background and objects, thus reflecting the slope of each sample. Subsequently, we introduce a method using the Euclidean distance and correction coefficients to predict values, allowing for the prediction of measurements regardless of changes in the wire's position. We achieve high accuracy for each measurement type, 99.1%, 98.7%, 92.6%, 92.5%, 99.9%, and 99.7%, achieving outstanding overall average accuracy of 97% across all measurements. This inspection method not only addresses the limitations of conventional visual inspections but also yields excellent results with a small amount of data. Moreover, relying solely on image processing, it is expected to be more cost-effective and applicable with less data compared to deep learning methods.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.9
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• pp.1651-1655
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• 2011

The reference impedances which is about 95% supply impedance value of residential consumers' supply impedances was published by IEC in 1980. The reference impedances are the standard values for use in determining the voltage disturbance characteristics of electrical equipment like the flicker. In IEC 60725, the reference impedances for premises having service current capacities less than 100A per phase and for service current capacities more than 100A per phase are recommended. And these reference impedances are targeted for the countries using 50Hz power frequency. Because of the frequency difference, the reactance values of the reference impedances will be increased in 60Hz power system like Korea, And also the reference impedances are different significantly each other according to declared voltage variation, power consumption and service wire length etc. Therefore It is needed to calculate the reference impedances suitable for domestic low-voltage power system. In this paper, the reference impedances for service current capacities less than 100A in 220/380V, 60Hz single-phase two wire and three-phase four wire low-voltage system are calculated, And the equations for service current capacities more than 100A to calculate the modulus value of maximum supply impedances are suggested base on IEC 60725 and the reference impedances for those are calculated on service current of 100A per phase.

• Structural Engineering and Mechanics
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• v.67 no.4
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• pp.391-401
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• 2018

Locally available Stainless Steel Wire Mesh (SSWM) bonded on a concrete surface with an epoxy resin is explored as an alternative method for the torsional strengthening of Reinforced Concrete (RC) beam in the present study. An experiment is conducted to understand the behavior of RC beams strengthened with a different configuration of SSWM wrapping subjected to pure torsion. The experimental investigation comprises of testing fourteen RC beams with cross section of $150mm{\times}150mm$ and length 1300 mm. The beams are reinforced with 4-10 mm diameter longitudinal bars and 2 leg-8 mm diameter stirrups at 150 mm c/c. Two beams without SSWM strengthening are used as control specimens and twelve beams are externally strengthened by six different SSWM wrapping configurations. The torsional moment and twist at first crack and at an ultimate stage as well as torque-twist behavior of SSWM strengthened specimens are compared with control specimens. Also the failure modes of the beams are observed. The rectangular beams strengthened with corner and diagonal strip wrapping configuration exhibited better enhancement in torsional capacity compared to other wrapping configurations. The numerical simulation of SSWM strengthened RC beam under pure torsion is carried out using finite element based software ABAQUS. Results of nonlinear finite element analysis are found in good agreement with experimental results.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.450-451
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• 2006

The method of conductor wiring is that a messenger wire is installed, the end of the wire is connected to the conductor and a engine puller pulls the conductor. The length of one section of wiring is $3{\sim}5km$ and one group messenger wire pulls simultaneously $2{\sim}4$ group conductor, while a tensioner maintains wiring tension to prevent the deflection of the conductor. However, there are many obstacles such as roads, power lines, communication lines, buildings, farms and crops. Therefore to prevent damage from conductor deflection a staging is used. The currently used staging is scaffolding lumber which is difficult to secure and it's construction efficiency is very low because it requires a lot of time and manpower. So this study developed a insulating defense tube and pipe connecting device, and a truss structure fabrication module using steel pipe which reduces construction time and cost through a compressive and dielectric strength test.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1881-1883
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• 2002

Recently, 345kV XLPE Cable and Accessories have been developed and will be applied for Youngseo$\sim$Youngdeungpo project in Korea. So, let this project and the process of development introduce on this paper. The cable type and length of this project is 345kv XLPE 1C*$2000mm^2$ 66km and all cable will be pulled on cable tunnel. The diameter of cable insulation was designed as 27mm, we could reduce it by appling for hi-tech and super-clean system. Joints were developed by a pre-fabricated type which considered high safety and economic issues. We had also done Pre-Qualification test for verifying the reliance of cable and accessories before construction. As we developed this 345kV XLPE cable system including its accessories at the same time, we can have higher technologies and contribute safe power in transmission lines. In adtionally, we can have a stable status for suppling EHV cable systems to a variety foreign customers by ourselves.

• Journal of Powder Materials
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• v.24 no.5
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• pp.389-394
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• 2017

Ni wires with a diameter and length of 0.4 and 100 mm, respectively, and a purity of 99.9% are electrically exploded at 25 cycles per minute. The Ni nanopowders are successfully synthesized by a pulsed wire evaporation (PWE) method, in which Ar gas is used as the ambient gas. The characterization of the nanopowders is carried out using X-ray diffraction (XRD) and a high-resolution transmission electronmicroscope (HRTEM). The Ni nanopowders are classified for a multilayer ceramic condenser (MLCC) application using a type two Air-Centrifugal classifier (model: CNI, MP-250). The characterization of the classified Ni nanopowders are carried out using a scanning electron microscope (SEM) and particle size analysis (PSA) to observe the distribution and minimum classification point (minimum cutting point) of the nanopowders.