• Composites Research
• /
• v.36 no.6
• /
• pp.454-460
• /
• 2023

Recently, regulations on greenhouse gas emissions have been strengthened, and the International Maritime Organization (IMO) has been strengthening greenhouse gas regulations with a goal of net 'zero' emissions by 2050. In addition, in the shipbuilding/offshore sector, it is important to reduce operating costs, such as improving propulsion efficiency and lightening structures. In this regard, research is currently being conducted on topology optimization using 3D printed composite materials to satisfy structural lightness and high rigidity. In this study, three topology shapes (hexagonal, square, and triangular) were applied to the interior of a rudder, a ship structure, using 3D printed composite materials. Structural analysis was performed to determine the appropriate shape for the rudder. CFD analysis was performed at 10° intervals from 0° to 30° for each rudder angle under the condition of 8 knots, and the load conditions were set based on the CFD analysis results. As a result of the structural analysis considering the internal topology shape of the rudder, it was confirmed that the triangular, square, and hexagonal topology shapes have excellent performance. The rudder with a square topology shape weighs 78.5% of the rudder with a triangular shape, and the square topology shape is considered to superior in terms of weight reduction.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.17 no.6
• /
• pp.1033-1038
• /
• 2022

In this paper, the design of a printed dipole antenna fed by broadside coupled striplines (BCS) for the 3.5GHz band is described. The two fins of the bow tie are, respectively, on the two sides of the substrate. The feeding balanced lines adopted for 1×2 array are the BCS. The obtained numerical results are in good agreement with experimental data. Through experiments with printed dipole antennas of various extended angles, the printed dipole antenna exhibits the wide bandwidth in the desired frequency band, which has a bandwidth of 28% for VSWR < 2.0 : 1. And within this bandwidth, This printed dipole antenna achieves a stable radiation pattern. It is found that the narrow band and feeding for array characteristic which is a disadvantage of the conventional printed dipole antenna can be improved. The radiation pattern showed omnidirectional characteristics and the maximum gain was about 4.4dBi.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.46 no.3
• /
• pp.50-56
• /
• 2009

Recently, according to the product variety of multimedia content some problems are occurred as like an illegal copying, an illegal distribution and a copyright infringement etc. So, for the solution of these problems, some methods were proposed as like watermarking which inserts the information of copyright to the content and the cipher for authentication to DRM which prevents an illegal copying using RSA. In this paper, the multimedia fingerprint based on BIBD code is inserted to the bit-plane of the image content for DRM with RSA, and while the decoding processing. The experiment is operated with the consideration of the image transmission and the transformation. As a result it confirmed that the multimedia fingerprint code inserted in image is detected 60% upper at AWGN 7dB and detected completely 100% at AWGN 10dB upper on PSNR 30, 40, 70 and 80 of Stirmark attacks.

• Journal of the Korean Society of Radiology
• /
• v.15 no.3
• /
• pp.307-312
• /
• 2021

In nuclear medicine, radioactive isotope tracers are administered to the human body to obtain and evaluate disease morphological information and biological function information. Dose calibrator is a device used to measure the radioactivity of a single nuclide in medical institutions. Administration of the correct dose to the human body acts as an important factor in diagnosis and treatment, and measurement through a dose calibrator before administration is the most important factor. Dose calibrator performs daily quality control after installation in each medical institution. Quality control is a means of guaranteeing quality control after installation, and is essential for improving the quality of treatment and promoting patient safety. Therefore, accurate and standardized performance evaluation methods should be established. In this study, 3D printing was used for quantitative evaluation of quality control by increasing the accuracy and standardization of quality control. When the 3D printer was installed and reproducibility was tested, the error range of the expected value and reading value decreased by 0.302% in the F-18 nuclide and 0.09% in the ^99mTc-pertechnate nuclide than when the 3D printer was installed. The error rate for other nuclides was also found to have a low error rate for reproducibility tests when 3D printing was installed.

• The Research Journal of the Costume Culture
• /
• v.26 no.6
• /
• pp.919-933
• /
• 2018

Recently, the textile and fashion industry has adopted 3D printing technology, through which filaments are accumulated continuously in the form of sections to produce digitalized three-dimensional fashion products. Little research has been done regarding the consumer perspectives on 3D printed fashion product. Therefore, the purpose of this study was to investigate the effects of consumer innovativeness, uniqueness, and perception factors on consumer attitudes and purchasing intentions for 3D printed fashion products. A questionnaire was given to consumers living in Seoul and Kyunggi, South Korea. The data obtained from the 159 completed questionnaires was analyzed by regression analysis, factor analysis, and Cronbach's alpha using SPSS 24.0. The results were as follows: First, consumer innovativeness and uniqueness, in descending order, positively affect the perceived social image. Consumer innovativeness positively affects perceived aesthetics and consumer uniqueness positively affects perceived novelty. Second, social image has a positive effect on consumer attitudes to 3D printed fashion products. Third, consumer attitude positively affects purchasing intentions towards 3D printed fashion products. Fourth, consumer innovativeness and uniqueness, in descending order, have a positive effect on consumer attitudes and purchasing intentions for 3D printed fashion products. Fifth, social image and novelty, in descending order, positively affect purchase intentions for 3D printed fashion products. Therefore fashion firms should develop their marketing strategy to focus on innovative, unique consumers as a main target and aim to enhance buyers' social image by using 3D printed fashion products.

• Journal of the Korean Society of Radiology
• /
• v.15 no.5
• /
• pp.697-704
• /
• 2021

It is hard to get Filaments which are materials of the 3D printing Fused Deposition Modeling(FDM) method as radiation shielding in Korea. and also related research is insufficient. This study aims to provide basic data for the development of radiation shields using 3D printing by evaluating the physical properties and radiation shielding capabilities of filaments containing metal particles. after selecting five metal filaments containing metal particle reinforcement materials, the radiation shielding rate was calculated according to the Korean Industrial Standard's protective equipment test method to evaluate physical properties such as tensile strength, density, X-ray Diffraction(XRD), and weight measurement using ASTM's evaluation method. In the tensile strength evaluation, PLA + SS was the highest, ABS + W was the lowest, and ABS + W is 3.13 g/cm³ which value was the highest among the composite filaments in the density evaluation. As a result of the XRD, it may be confirmed that the XRD peak pattern of the particles on the surface of the specimen coincides with the pattern of each particle reinforcing material powder metal, and thus it was confirmed that the printed specimen contained powder metal. The shielding effect for each 3D printed composite filament was found to have a high shielding rate in proportion to the effective atomic number and density in the order of ABS + W, ABS + Bi, PLA+SS, PLA + Cu, and PLA + Al. In this study, it was confirmed that the metal particle composite filament containing metal powder as a reinforcing material has radiation shielding ability, and the possibility of using a radiation shielding filament in the future.

• Journal of the Korea Society of Computer and Information
• /
• v.24 no.11
• /
• pp.61-69
• /
• 2019

In this paper, we propose a multisensory(i.e., visual-auditory-tactile) based AR system for the education of cultural heritage. The proposed system provides a multisensory interaction by designing a user to experience with a 3D printed artifact which is mapped by a virtual 3D content of digital heritage. Compared with the existing systems of cultural heritage education based on augmented reality(AR) technology, this system focused on not only providing learning experience via a sense of visual and auditory, but also a sense of tactile. Furthermore, since this systems mainly provided the direct interactions using a 3D printed model, it gives a higher degree of realism than existing system that use touch or click motions on a 2D display of mobile phones and tablets. According to a result of user testing, we concluded that the proposed system delivered the excellent presence and learning flow to users. Particularly, from the usability evaluation, a 3D printed target artifact which is similar in shape to original heritage artifact, achieved the highest scores among the various tested targets.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.16 no.9 s.100
• /
• pp.926-931
• /
• 2005

In this paper, the printed-sleeve monopole antenna which has the small size and the broadband characteristics, is presented and its radiation characteristics are investigated. To conform the broadband characteristics of the proposed antenna, the experimental antenna is designed, fabricated, and its radiation characteristics are measured in PCS band (1.75 GHz${\~}$1.87 GHz). It is shown that the designed antenna has the non-directional pattern in the horizontal plane, the directional pattern in the vertical plane, VSWR less than 1.5, and gain in 2.14 dBi${\~}$3.4 dBi. From these results, the proposed antenna is conformed as a broadband antenna which can be used for the mobile communication indoor antenna extensively.

• Journal of Korea Multimedia Society
• /
• v.14 no.3
• /
• pp.414-422
• /
• 2011

The paper is for top and bottom symmetrical phase controlled loop antenna using for multi-media devices. We developed a top and bottom phase control loop pattern arrangement methods for loop antenna in mobile devices like as a cell phone and PCS, WCDMA. In the loop antenna pattern, arrange close adhesive the loop antenna pattern $180^{\circ}$ cycle in wave length, the radiated electro-magnetic wave from close adhesive loop pattern in $180^{\circ}$ become to coherent wave than the phase controlled loop antenna has high efficiency and high radiation gain. To acquire a wide band width on phase controlled loop antenna, we arrange a top and bottom symmetrical architecture loop pattern that bas a $180^{\circ}$ wave length in each layer. Top and bottom each layer bas a U form pattern separated $90^{\circ}$ wave length each other. This architecture cause a well balanced electro-magnetic flow control that acquired wide bandwidth resonance response in loop pattern antenna. In experiment, we designed a WCDMA mobile multi-media antenna in $40mm{\times}6mm$ area thickness 0.2mm, in that passive experiment the radiation efficiency is over 50% and over 0dBi radiation average gain was acquired, in the active experiment in real multi-media device we acquired -4dBi average gain and 43% transmit/receive efficiency.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.22 no.11
• /
• pp.1101-1110
• /
• 2011

This paper presents a printed, wideband folded monopole antenna for laptop and tablet computer applications. The proposed antenna is designed to cover bandwidth(2.3~10.6 GHz) of Bluetooth, WiMAX, and UWB system by using the printed folded monopole antenna having asymmetrical line width coupling with a parasitic inverted- L element. Also, wireless LAN band(5.15~5.85 GHz) which interferes with UWB system is rejected by inserting half-wavelength open stub in the folded monopole antenna. -10 dB bandwidth of the fabricated wideband antenna is 2.27~10.6 GHz (4.7:1) and -10 dB band-rejected bandwidth is measured as 700 MHz(5.15~5.85 GHz, 12.72 %). The gain and efficiency of the antenna except for the rejected band are higher than 3.93 dBi and 91.89 % and are measured as -2 dBi and 14.65 % at 5.5 GHz which is band-rejected frequency. The size of the antenna is suitable to install for small space of tablet and laptop computers as 12.75(1 ${\lambda}$/10)${\times}$12(1 ${\lambda}$/11) $mm^2$(${\lambda}$ is free space wavelength at 2.3 GHz). Therefore, we verified that the designed antenna is appropriate for wideband antenna of tablet and laptop PC applications.