• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.4
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• pp.819-830
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• 1999

NAVTEX system is an international automated direct-printing service, broadcast on 5181kHz and 490kHz, for the promulgation of navigational and meteorological warnings and urgent information to ships. With our government's adoption of the international convention for SAR(Search and Rescue) in 1993, various trials for the installation of NAVTEX system have been executed by the government committee, relating laboratory and experts. An important consideration of the installation for NAVTEX system is the availability that could broadcast messages written in korean letter. Also, the receiver which can process the signal demodulated from the two frequencies, 518kHz and 490kHz, should be developed and supplied in domestic. In this paper, the code table and algorithm for conversions between NAVTEX characters and Korean Letters are studied, and signal processing techniques of code conversion are developed. Circuit design and implementation of the NAVTEX simulator using the Direct Digital Synthesizer are discussed, code conversion algorithm and signal processing technique of the NAVTEX transmission are programmed in its circuits. For evaluating the its functional characteristics, receiving module which has I-Q channel structure is designed. From the measurements of simulator, the characteristics show the frequency stability of the $(\pm)2Hz$ and Spurious free dynamic range is -63dBc. And the simulator can generate simultaneously wanted signal and several interfere signals. So, its capability is valuable for designers of the transmitting system and NAVTEX receiver, for provider as testing facilities of the type approval.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.251-252
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• 2016

Recently policy and clouding system to mandate the introduction of BIM in construction industry, various sensors technology, BIM in ICT technology and fusion, such as 3D scanning and printing technology has been further activated. However, the expression level of diversification associated with it, plan within one of the BIM project, design, engineering, it is difficult to have a different application has been consistent for each field, such as construction. Thus fell the efficiency of BIM apply, it is difficult to determine the appropriate level of BIM in the business early stage in order destination of position. In this study, in order to solve this problem, by utilizing SLA used in the IT field, it attempts to explore scheme which can be evaluated targeted level of BIM suitable for business in the planning phase.

• IE interfaces
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• v.23 no.1
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• pp.58-67
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• 2010

The purpose of this paper is to present the development processes of the assembly line tester of power transmission for lift truck. Because power transmission is most important part of lift truck, all assembled powertrain parts must be inspected for operational defects, pressures and RPM. Developed assembly line tester is designed to take about 25 minutes for inspecting each assembled power transmission and located it at the end of assembled line. The assembly line no-load tester consists of three parts: (1) the driving hardware part; for installing and operating the transmission. (2) control PCB part; send data from sensors to a computer and control driving part, (3) operation software of no-load tester; for an automatic inspection or manual inspection, for database management and printing transcripts.

• Smart Structures and Systems
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• v.32 no.2
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• pp.111-121
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• 2023

This study proposes an automated assembly performance evaluation method for prefabricated steel structures (PSSs) using machine learning methods. Assembly component images were segmented using a modified version of the receptive field pyramid. By factorizing channel modulation and the receptive field exploration layers of the convolution pyramid, highly accurate segmentation results were obtained. After completing segmentation, the positions of the bolt holes were calculated using various image processing techniques, such as fuzzy-based edge detection, Hough's line detection, and image perspective transformation. By calculating the distance ratio between bolt holes, the assembly performance of the PSS was estimated using the k-nearest neighbors (kNN) algorithm. The effectiveness of the proposed framework was validated using a 3D PSS printing model and a field test. The results indicated that this approach could recognize assembly components with an intersection over union (IoU) of 95% and evaluate assembly performance with an error of less than 5%.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.80-80
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• 2009

$BaTiO_3$ has high permittivity so that has been applied to dielectric and insulator materials in 3D system-level package integration. In order to achieve excellent performance of device, the $BaTiO_3$ layer should be highly dense. In this study, $BaTiO_3$ thick films were prepared by the inkjet printing method using 4 vol.% $BaTiO_3$ colloidal inks and cured at $28^{\circ}C$ for 5 h after infiltration of polymer resin for non-sintered process using 3 vol.% cyanate ester emulsion ink. From the obtained results. packing density was determined to be improved by overlapping rabbit ears which were generated by coffee ring effect. We also calculated the packing densities of the films and correlated these packing densities to the measured permittivity of the films.

• Journal of the Korean Vacuum Society
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• v.7 no.s1
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• pp.20-24
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• 1998

Photploymer films are widely used in printing and electronic industries, and their usage is expanding to encompass holography, data storage and data processing, optical waveguides and compact disks, etc. One of widely used photoplymerization initiator, 20chloro-hexaarylbiimidazole (o-Cl-HABI), is studied by laser flash photolysis in dichloromethane solution in the absence and presence of the visible light photosensitizing dye, 2, 5-bis[(2, 3, 6, 7 -tetrahydro- 1H, 5H -benzo [i, j,] quinolizin -1-yl) methylene]-cyclopenta-none, (JAW). In the presence of JAW, an increase in triarylimidazolyl radicals L.formation is observed in relative to the absence of JAW. The mechanism of this photosensitizing dissociation is concluded as the dissociation of the o-Cl-HABI radical anion formed by the electron transfer from excited singlet state of JAW to o-Cl-HABI. The observed formation of L.radicals exhibits a linear dependence on o-Cl-HABI concentration. The rate constant of electron transfer obtained from this dependence is equal to (1.0$\pm$0.2) x $10^9 M^{-1}s^{-1}$. No reaction between the excited triplet state of JAW and o-Cl-HABI is found.

• The Journal of the Convergence on Culture Technology
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• v.6 no.4
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• pp.123-130
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• 2020

Prior to the introduction of automated systems such as jewelry CAD and CAM, the jewelry manufacturing industry had many originals made by hand. However, after the introduction of the automated system, original craftsmen with high technology have disappeared, and computer designers and 3D printing print engineers are taking their place. The introduction of automated systems such as CAD and CAM in the existing hand-made production line has resulted in diversification of designs and cutting-edge and specialization of jewelry manufacturing. In the domestic jewelry industry, the dependence of automation systems such as CAD and CAM in the manufacturing process continues to increase, and the situation is taking up more and more parts in the jewelry design curriculum of universities. From these results, the CAD/CAM automation system field in the jewelry manufacturing industry becomes an essential and important field in the future.

• Polymer(Korea)
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• v.38 no.6
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• pp.815-819
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• 2014

Scaffolds of tissue engineering should be biocompatible and biodegradable for cell attachment, proliferation and differentiation. In the various scaffold fabrication, 3D printing technique can make the three dimensional scaffold with interconnected pores for cell ingrowth. Polycaprolactone (PCL) is biodegradable polyester with a low melting temperature and has been approved by the Food and Drug Administration (FDA). In this study, PCL scaffold was fabricated by 3D bioprinting system and surface modification of PCL scaffold was controlled by NaOH treatment. Morphological change and wetability of NaOH-treated scaffold were observed by SEM and contact angle measurement system. The remnant of PCL treated with NaOH was measured by ATR-FTIR. In vitro study of scaffolds was evaluated with WST-1 and ALP activity assay. NaOH treatment of PCL scaffolds increased surface roughness, hydrophilicity, cell proliferation and osteogenic differentiation. These results indicate that NaOH-treated PCL scaffold made by 3D bioprinting has tissue engineered potential for the development of biocompatible material.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.551-556
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• 2018

With the rise of the fourth industrial revolution, the importance of establishing R&D strategies to develop ICT technologies such as Big Data, Artificial Intelligence, Robots, the Internet of Objects, and 3D Printing is increasing. In this study, we analyzed the effects of the fourth industrial revolution on society and the present state of the national defense technology planning system, and proposed improvement measures for the utilization of the fourth industrial revolution in the defense industry from the perspective of defense R&D. The current defense R&D strategy focuses on securing the core technologies of each weapon system required by the military through research and development. Under the current system, the role of fourth industrial revolution technology will be confined to some of the weapons systems required by the military. In order to overcome this limitation, we propose a technology roadmap for the future weapons systems.

• Journal of Environmental Health Sciences
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• v.3 no.1
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• pp.27-44
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• 1976

This study was carried out to evaluate the harmful factors in working environments and to investigate the labor productivity after improvement of environments, surveying 93 industrial establishments of 10 industries located in Youngdeungpo industrial area in Seoul. The results obtained were as follows: 1) The highest noise level of 125dB(A) was indicated at the rolling process of transport equipment manufacturing industry. 2) The best illumination level was shown in precise machinery industry and the worst was indicated in rubber products, metallic products and transport equipment manufacturing industries. 3) Thermal conditions were above threshold limit value (TLV) at more than two processes of all industries except printing industry. 4) The highest dust concentration was determined in textile and wearing manufacturing industry. 5) Organic solvents were detected at 52 processes in 93 industrial establishments and 33 processes of them showed higher than TLV. The results about harmful chemicals were as follows: a) sulfur dioxide ($SO_2$)was determined higher than TLV on welding process of metallic product manufacturing industry and heat treatment process of transport equipment manufacturing industry. b) Carbon monoxide (CO) concentration was 700ppm at heat treatment process of transport equipment manufacturing industry, indicating 14 times of TLV. c) vinylchloride concentration in the air of PVC raw material mixing process and PVC preparation process of chemical product manufacturing industry was determined higher than TLV. d) Hydrochloride (HCl) concentration in the air of wire expanding process of transport equipment manufacturing industry was determined higher than TLV. 7) Higher values of lead concentration than TLV were determined at lead welding metallic product manufacturing industry and type planting process of process of printing industry, $1.8mg/m^3$ and $0.3mg/m^3$ respectively. 9) 22, 968 of 52, 855 workers (i.e. 43.5%) in 93 industries were exposed to various harmful agents. 10) It was found that the improvement of illumination in electric apparatus manufacturing industry (from 20~40 lux to 420 lux) resulted in an increase in productivity of 6.5% per capita and a decrease in faulty products of 19%. 11) Improvement of environments using local exhaust ventilation system resulted in a decrease of harmful substances lower than TLV and an increase in productivity of 11.4%. 12) Improvement of shovelling tools based on ergonomics resulted in a reduction in energy expenditure of 25.3% and an increase in productivity of 32.2% per capita.