• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.14 no.7
• /
• pp.2957-2980
• /
• 2020

Ensemble clustering commonly integrates multiple basic partitions to obtain a more accurate clustering result than a single partition. Specifically, it exists an inevitable problem that the incomplete transformation from the original space to the integrated space. In this paper, a novel ensemble clustering algorithm using a newly reconstructed mapping coefficient (ECRMC) is proposed. In the algorithm, a newly reconstructed mapping coefficient between objects and micro-clusters is designed based on the principle of increasing information entropy to enhance effective information. This can reduce the information loss in the transformation from micro-clusters to the original space. Then the correlation of the micro-clusters is creatively calculated by the Spearman coefficient. Therefore, the revised co-association graph between objects can be built more accurately because the supplementary information can well ensure the completeness of the whole conversion process. Experiment results demonstrate that the ECRMC clustering algorithm has high performance, effectiveness, and feasibility.

• Journal of the Korean Society of Industry Convergence
• /
• v.26 no.4_1
• /
• pp.517-527
• /
• 2023

Many techniques have been proposed and investigated for microlens array manufacturing in three-dimensional (3D) structures. We present fabricating a microlens array using selective laser etching and a CO₂ laser. The femtosecond laser was employed to produce multiple micro-cracks that comprise the predesigned 3D structure. Subsequently, the wet etching process with a KOH solution was used to produce the primary microlens array structures. To polish the nonoptical surface to the optical surface, we performed reflow postprocessing using a CO₂ laser. We confirmed that the micro lens array can be manufactured in three primary shapes (cone, pyramid and hemisphere). Compared to our previous study, the processing time required for laser processing was reduced from approximately 1 hour to less than 30 seconds using the proposed processing method. Therefore, micro lens arrays can be manufactured using our processing method and can be applied to mass productionon large surface areas.

• Polymer(Korea)
• /
• v.32 no.4
• /
• pp.334-339
• /
• 2008

Recently electro spinning is a widely used simple technique to prepared micro- to nanometer-sized fiber of various polymers. In general, a normal multiple-nozzle electro spinning system has been difficult to achieve high production-rate fabricating micro/nanofibers due to the interference of electric field between individual nozzles in the process. To reduce the interference effect of electric field between nozzles, we developed a multi-nozzle electrospinning system supplemented with auxiliary electrodes. Poly($\varepsilon$-carprolactone)(PCL), which has good mechanical property and biocompatibility, was electrospun by the multi-nozzle electro spinning system. Electrospinnability, product rate, and size uniformity of spun fibers for the system with and without auxiliary electrodes were characterized. As a result, the multi-nozzle electrospinning system supplemented with auxiliary electrodes provides excellently stable processability and showed high mass productivity of PCL-nanofibers relative to a normal multi-nozzle electro spinning system.

• Korean Journal of Materials Research
• /
• v.15 no.9
• /
• pp.589-593
• /
• 2005

Nanoimprinting lithography (NIL) is known as a suitable technique for fabricating nano and micro structures of high definition. Hot embossing is one of NIL techniques and can imprint on thin films and bulk polymers. Key issues of hot embossing are time and expense needed to produce a stamp withstanding a high temperature and pressure. Fabrication of a metal stamp such as an electroplated nickel is cost intensive and time consuming. A ceramic stamp made by silicon is easy to break when the pressure is applied. In this paper, a plastic stamp using a high temperature epoxy was fabricated and tested. The plastic stamp was relatively inexpensive, rapid to produce and durable enough to withstanding multiple hot embossing cycles. The merits of low viscosity epoxy solutions were a fast degassing and a rapid filling the microstructures. The hot embossing process with plastic stamp was performed on PMMA substrates. The hot embossing was conducted at 12.6 bar, $120^{\circ}C$ and 10 minutes. An imprinted PMMA wafer was almost same value of the plastic stamp after 10 times embossing. Entire fabrication process from silicon master to plastic stamp was completed within 12 hours.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.20 no.10
• /
• pp.88-94
• /
• 2021

Machining operations require the removal of chips to keep the water-soluble cutting oil clean and fresh throughout the operation time. Water-soluble cutting oil for metal processing is diluted using a 3-8% solution in water which is generally replaced every three to six months. This study aims to develop multiple purification devices to efficiently remove fine contaminating particles from water-soluble cutting oil. The 2D concept designs were created using AutoCAD. The designs were drawn using the 3D modelling feature of CATIA. Flow analysis was performed in a bubble purifier using Ansys computational fluid dynamics (CFD). This analysis has aided in improving the design and structure of the device to create the final prototype. Experiments were conducted to check the prototype's performance. Comparisons of the effects of each process variable on the experiment was carried out using ANOVA.

• Elastomers and Composites
• /
• v.44 no.3
• /
• pp.222-231
• /
• 2009

Shirasu-porous-glass (SPG) membrane emulsification is highly attractive in the field of toner industries, foods and drug delivery systems because of its easy control of particle size in micro-scale, narrow size distribution and multiple emulsion. The particle size and morphology of emulsion droplets can be controlled by changing the type of initiators, additives, monomers, crosslinkers and inhibitors in SPG membrane emulsification. In this paper, principles of SPG membrane emulsification, influence of process parameters and industrial applications have been addressed.

• Proceedings of the Membrane Society of Korea Conference
• /
• 1996.06a
• /
• pp.177-189
• /
• 1996

Raverase osmosis or ultrafiltration systems have generally been regarded as hard to validate about WFI production. Though the Japanese and US Pharmacopoeias have allowed distillation and RO to be applied to WFI production process, only water stills, especially multiple effects have practically been employed for parenteral water production. On the other hand, the latest analysis has shown that even distillate contains such volatile organic matters as trihalomethanes and traces of heavy metals at a little higher concentration than supposed. The JP requires TOC to be monitored in WFI process based on RO or UF systems to control the concentration below 300ppb, but very few monographs or papers have so far been published about the concentrations of organic volatile matters in distillate. (See table 1-1) Therefore, this paper proposes a new applicable WFI systems based on the result of purified water analysis with some membranes used in the process. A well combined membrane system with other units could be expected to provide less amount of impurities in membrane-treated water than in distillate.

• Design & Manufacturing
• /
• v.12 no.2
• /
• pp.46-50
• /
• 2018

Recently, as machine components and products are getting smaller, it is demanded to develop superprecision production technologies multilaterally. Along with the advancement of production technology, people are paying keener attention to the development of eco-friendly technology and efficient processing technology. Particularly, in many industries related to automobiles, shipbuilding, or airplane components, it is demanded to obtain technology to process multiple micro-holes. On account of this trend, micro-hole processing employing high-power electron beams is rising nowadays, and more interest is being shown in it, too. In Korea, however, the process of manufacturing vaporized amplification sheets influencing high-power electron beam processing technology and the processability considerably has not been developed sufficiently yet. Therefore, this study has applied vaporized amplification sheets manufactured to analyze the processability of high-power electron beams and examine necessity for vaporized amplification sheets.

• Journal of the Korean Society for Precision Engineering
• /
• v.23 no.4 s.181
• /
• pp.183-190
• /
• 2006

Digital 3D Real Object Duplication System (RODS) consists of 3D Scanner and Solid Freeform Fabrication System (SFFS). It is a device to make three-dimensional objects directly from the drawing or the scanning data. In this research, we developed an office type SFFS based on Three Dimensional Printing Process and an industrial SFFS using Dual Laser. An office type SFFS applied sliding mode control with sliding perturbation observer (SMCSPO) algorithm for control of this system. And we measured process variables about droplet diameter measurement and powder bed formation etc. through experiments. In case of industrial type SFFS, in order to develop more elaborate and speedy system for large objects than existing SLS process, this study applies a new Selective Dual-Laser Sintering (SDLS) process and 3-axis Dynamic Focusing Scanner for scanning large area instead of the existing f lens. In this process, the temperature has a great influence on sintering of the polymer. Also the laser parameters are considered like that laser beam power, scan speed, and scan spacing. Now, this study is in progress to evaluate the effect of experimental parameters on the sintering process.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.5
• /
• pp.475-480
• /
• 2017

In this paper, the conductivity of the fine pattern is improved in the insulating substrate by laser-induced forward transfer (LIFT) process. The high laser beam energy generated in conventional laser induced deposition processes induces problems such as low deposition density and oxidation of micro-patterns. These problems were improved by using a polymer coating layer for improved deposition accuracy and conductivity. Chromium and copper were used to deposit micro-patterns on silicon wafers. A multi-pulse laser beam was irradiated on a metal thin film to form a seed layer on an insulating substrate(SiO2) and electroless plating was applied on the seed layer to form a micro-pattern and structure. Irradiating the laser beam with multiple scanning method revealed that the energy of the laser beam improved the deposition density and the surface quality of the deposition layer and that the electric conductivity can be used as the microelectrode pattern. Measuring the resistivity after depositing the microelectrode by using the laser direct drawing method and electroless plating indicated that the resistivity of the microelectrode pattern was $6.4{\Omega}$, the resistance after plating was $2.6{\Omega}$, and the surface texture of the microelectrode pattern was uniformly deposited. Because the surface texture was uniform and densely deposited, the electrical conductivity was improved about three fold.