• Journal of Korean Society for Quality Management
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• v.45 no.2
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• pp.191-207
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• 2017

Purpose: To develop an interactive version of the conventional process capability-based approach, called 'Interactive Process Capability-Based Approach (IPCA)' in multi-response surface optimization to obtain a satisfactory compromise which incorporates a decision maker(DM)'s preference information precisely. Methods: The proposed IPCA consists of 4 steps. Step 1 is to obtain the estimated process capability indices and initialize the parameters. Step 2 is to maximize the overall process capability index. Step 3 is to evaluate the optimization results. If all the responses are satisfactory, the procedure stops with the most preferred compromise solution. Otherwise, it moves to Step 4. Step 4 is to adjust the preference parameters. The adjustment can be made in two modes: relaxation and tightening. The relaxation is to make the importance of one of the satisfactory responses lower, which is implemented by decreasing its weight. The tightening is to make the importance of one of the unsatisfactory responses higher, which is implemented by increasing its weight. Then, the procedure goes back to Step 2. If there is no response to be adjusted, it stops with the unsatisfactory compromise solution. Results: The proposed IPCA was illustrated through a multi-response surface problem, colloidal gas aphrons problem. The illustration shows that it can generate a satisfactory compromise through an interactive procedure which enables the DM to provide his or her preference information conveniently. Conclusion: The proposed IPCA has two major advantages. One is to obtain a satisfactory compromise which is faithful to the DM preference structure. The other is to make the DM's participation in the interactive procedure easier by using the process capability index in judging satisfaction/unsatisfaction. The process capability index is very familiar with quality practitioners as well as indicates the process performance levels numerically.

• Proceedings of the KSRS Conference
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• v.1
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• pp.150-152
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• 2006

The DISCOVER Project (${\underline{D}}istributed$ ${\underline{I}}nformation$ ${\underline{S}}ervices$ for ${\underline{C}}limate$ and ${\underline{O}}cean$ products and ${\underline{V}}isualizations$ for ${\underline{E}}arth$ ${\underline{R}}esearch$) is a NASA funded Earth Science REASoN project that strives to provide highly accurate, carefully calibrated, long-term climate data records and near-real-time ocean products suitable for the most demanding Earth research applications via easy-to-use display and data access tools. A key element of DISCOVER is the merging of data from the multiple sensors on multiple platforms into geophysical data sets consistent in both time and space. The project is a follow-on to the SSM/I Pathfinder and Passive Microwave ESIP projects which pioneered the simultaneous retrieval of sea surface temperature, surface wind speed, columnar water vapor, cloud liquid water content, and rain rate from SSM/I and TMI observations. The ocean products available through DISCOVER are derived from multi-sensor observations combined into daily products and a consistent multi-decadal climate time series. The DISCOVER team has a strong track record in identifying and removing unexpected sources of systematic error in radiometric measurements, including misspecification of SSM/I pointing geometry, the slightly emissive TMI antenna, and problems with the hot calibration source on AMSR-E. This in-depth experience with inter-calibration is absolutely essential for achieving our objective of merging multi-sensor observations into consistent data sets. Extreme care in satellite inter-calibration and commonality of geophysical algorithms is applied to all sensors. This presentation will introduce the DISCOVER products currently available from the web site, http://www.discover-earth.org and provide examples of the scientific application of both the diurnally corrected optimally interpolated global sea surface temperature product and the 4x-daily global microwave water vapor product.

• Fashion & Textile Research Journal
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• v.16 no.2
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• pp.326-332
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• 2014

To develop cool touch feeling fabrics for summer clothing material, it was manufactured several compositions of woven fabrics, having rayon multi-filament yarn (non-twisted) as warp and various kinds of yarn, such as viscose rayon multi-filament yarn (twisted), tencel$^{(R)}$ spun yarn, PET high absorbance quick dry filament yarn, and PET based rayon-like yarn, as weft. After preparing the fabrics, basic properties of the fabrics were investigated, such as air-permeability, tensile strength, absorption rate, drying rate, etc. Also, surface warm / cool sensations of the woven fabrics were assessed by Qmax Warm / Cool Touch Tester. It was observed that the fabrics composed of viscose rayon multi-filament yarn (warp) and PET high absorbance quick dry filament yarn (weft) showed excellent surface cool touch sensation-the highest Qmax value. This is because the fabric having flat shaped PET high absorbance quick dry filament shows the largest contact area with Qmax measuring plate. And, the fabric also showed superior high absorbance and quick dry property as expected. In addition, we treated phase change material (PCM) on the surface of the fabric composed of viscose rayon multi-filament yarn (warp) and PET high absorbance quick dry filament yarn(weft) to improve the cool touch feeling. However, the surface cool touch feeling was impaired by resin treated with PCM during the finishing process.

• Journal of the Korean Applied Science and Technology
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• v.31 no.4
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• pp.679-687
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• 2014

In this study, a new paint which is able to resist the cavitation erosion is tried to be developed by using urethane added with nano particles such as multi-wall and single-wall carbon nano tube and spherical and fiber type graphite. The new paint synthesized was characterized with physical properties and resistivity to cavitation erosion($t_{50}$). Among nano particles, fiber type graphite($t_{50}$ 292min) showed high hardness and wear resistance compared with spherical type($t_{50}$ 182min). For carbon nano tube, single-wall type($t_{50}$ 286min) was higher than multi-wall type in wear resistance. Fiber-type graphite was the best nano-particle for paint with resistivity to cavitation erosion. In the application test of paint, the manually painted sample showed surface with smooth but the surface of sample prepared with spray was not smooth. During spray, dust was fixed on the surface.

• Journal of the Korean institute of surface engineering
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• v.34 no.5
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• pp.409-413
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• 2001

In this study, high rate deposition of thick CrNx films was carried out by crossed field unbalanced magnetron sputtering for the special application such as piston ring employed in automobile engine. For the high rate deposition and thick CrNx films formation with thickness of 30$\mu\textrm{m}$, high power density of $35W/cm^2$ in each target was induced and the multi-layer films of Cr/CrN and $\alpha$-Cr/CrN were synthesized by control of $N_2$ flow rate. The dynamic deposition rate of Cr and $\alpha$-CrN film was reached to 0.17$\mu\textrm{m}$/min and 0.12$\mu\textrm{m}$/rnin and the thick CrN$_{x}$. film of 30$\mu\textrm{m}$ could be obtained less than 5 hours. The maximum hardness was obtained above 2200 kg/mm$^2$ and adhesion strength was measured in about 70N, in case of multi-layers films. And the friction coefficient was measured by 0.4, which was similar to the value of CrN single-layer film.m.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.130-130
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• 2016

Bioinspired hierarchical nanostructures for self-cleaning s-tnwjurface and SERS substrates are investigated. The multi-level hierarchy is combined with CuO nanowire and additional nanoscale structures. CuO nanowire, which has extremely high aspect ratio, serves as a base structure of multi-level hierarchy and additional flower like structures are placed on the CuO nanowires. Since as-fabricated CuO nanostructures are hydrophilic, the surface is coated with perfluorooctyltrichlorosilane in order to change its wetting property to hydrophobic. While those CuO based nanostructures have a sufficient roughness for superhydrophobic characteristics, hierarchical nanoflowers on nanowire structures lead to a self-cleaning surface. Furthermore, flower like nanostructures provide reentrant curvatures, thus enabling oleophobic property. The surfaces has a repellency even for a tiny droplet (10 nL) of low surface tension liquids (~35 mN/m). On the on hands, nanoflowers provide many number of nanoscale gaps. After a thin layer of silver is deposited on the surface of CuO nanostructures, those nanoscale gaps act as hot-spot for surface enhanced Raman scattering (SERS). To analyze SERS enhancement of the surfaces, Raman shift is measured with varying molar density of 4-Mercaptopyridine from mM to pM. From these results, hierarchical CuO nanostructures are suitable for self-maintenance and cost effective SERS sensing applications.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.6 s.144
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• pp.583-592
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• 2005

The turbulent free surface flow around a self-propelled KRISO 138K LNG Carrier is numerically simulated using the finite volume based multi-block RANS code, WAVIS developed at HRISO. The realizable k-$\varepsilon$ turbulence model with a wail function is employed for the turbulence closure. The free surface is captured with the Level-Set method and body forces are used to model the effects of a propeller without resolving the detail blade flow. In order to obtain an accurate free surface solution and stable convergence, the computations are executed with a proper fine grid refinement around the free surface and with an adoption of implicit discretization scheme for the Level-Set formulation. The computed velocity vectors at the several stations and wave patterns show a good agreement with the experimental results measured at the KRISO towing tank.

• Korean Chemical Engineering Research
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• v.50 no.3
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• pp.403-409
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• 2012

Polyurethane prepolymers were prepared from poly (carbonate diol), isophrone diisocyanate, and dimethylol propionic acid. Then, aniline terminated waterborne polyurethane dispersion (ATWPUD) was synthesized by capping aniline on the NCO group of the prepolymer. Subsequently, ATWPUD was mixed with multi-walled carbon nanotube (MWCNT) to yield coating solutions, and the mixture was coated on the polycarbonate substrate. The surface resistance ($10^{7.6}{\sim}10^{7.7}{\Omega}/cm^2$) of coating films from ATWPUD showed better conducting properties than that ($10^{10.9}{\Omega}/cm^2$) from pure waterborne polyurethane dispersion (WPUD) when MWCNT was mixed. Also, the surface resistance of coating films was increased, but the pencil hardness and adhesion were decreased with increasing the amount of MWCNT added in the ATWPUD.

• Korean Journal of Materials Research
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• v.31 no.7
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• pp.420-426
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• 2021

Graphene, a new material with various advantageous properties, has been actively used in various fields in recent years. Applications of graphene oxide are increasing in combination with other materials due to the different properties of graphene oxide, depending on the number of single and multiple layers of graphene. In this study, single-layer graphene oxide and multi-layer graphene oxide are spray coated on polystyrene, and the physicochemical properties of the coated surfaces are characterized using SEM, Raman spectroscopy, AFM, UV-Vis spectrophotometry, and contact angle measurements. In single-layer graphene oxide, particles of 20 ㎛ are observed, whereas a 2D peak is less often observed, and the difference in surface height increases according to the amount of graphene oxide. Adhesion increases with an increase in graphene oxide up to 0.375 mg, but decreases at 0.75 mg. In multi-layer graphene oxide, particles of 5 ㎛ are observed, as well as a 2D peak. According to the amount of graphene oxide, the height difference of the surface increases and the adhesive strength decreases. Both materials are hydrophilic, but single-layer graphene oxide has a hydrophilicity higher than that of multi-layer graphene oxide. We believe that multi-layer graphene oxide and single-layer graphene oxide can be implemented based on the characteristics that make them suitable for application.

• Membrane and Water Treatment
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• v.1 no.1
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• pp.61-74
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• 2010

This paper will integrate models at different levels (from filtration, backwashing to chemical cleaning and membrane lifetime) that can be used to minimize overall operating costs of a dead-end ultra filtration process that is used for the purification of surface water. Integration of the models leads to a multi-level optimization problem (at different levels different objectives should be reached). This problem is solved as a MINLP. Systematic modelling and optimization of membrane systems is not extensively discussed in the scientific literature. In this paper the first steps are taken in the formulation of proper models and the use of systems engineering tools to come to real optimal operating conditions. The optimized variables are used to calculate fouling profiles which can subsequently be used as inputs for a control system that actually enforces the profiles to a real pilot plant.