• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.1
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• pp.8-13
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• 2016

A pattern-switchable origami antenna is designed with paper using inkjet-printing technology. The proposed antenna can be switched between loop and dipole antenna modes by folding and unfolding the paper, respectively. The proposed antenna is designed for the resonant frequencies of both modes to be 1.85 GHz. Eutectic gallium-indium liquid metal is introduced in order to avoid cracks in the conductive ink when the paper is folded. The performance of the proposed antenna is demonstrated through simulation and measurement results and antenna gain of dipole-mode and loop-mode are -4 dBi and -5 dBi, respectively. Also, the nulls of both dipole and loop modes compensate nulls from each mode.

• Journal of the Korea Society of Computer and Information
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• v.13 no.6
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• pp.87-94
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• 2008

Iris diagnosis is an alternative medicine technique whose proponents believe that patterns, colors, and other characteristics of the iris can be examined to determine information about a patient's systemic health. However, because most of previous studies only find a sign pattern in a gray iris image, they are not enough to be used for a iris diagnosis system. In this paper, we developed an iris diagnosis system based on a color image processing and iris medical information stored in database. The system includes four modules : input module with an iris camera, iris signs extraction module, medical database, output module with printing. Based on a color image processing approach, this paper presents the extraction algorithms of 7 major iris signs and correction manually for improving the accuracy of analysis. We can use the iridology and patient's health DB in the stage of signs analysis. Compared with the existing system, the developed system can be applied to an iris diagnosis system since it provides various additional functions.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.431-431
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• 2011

Graphene, two dimensional sheet of sp2-hybridized carbon, has attracted an enormous amount of interest due to excellent electrical, chemical and mechanical properties for the application of transparent conducting films, clean energy devices, field-effect transistors, optoelectronic devices and chemical sensors. Especially, graphene is promising candidate to detect the gas molecules and biomolecules due to the large specific surface area and signal-to-noise ratios. Despite of importance to the disease diagnosis, there are a few reports to demonstrate the graphene- and rGO-FET for biological sensors and the sensing mechanism are not fully understood. Here we describe scalable and facile fabrication of rGO-FET with the capability of label-free, ultrasensitive electrical detection of a cancer biomarker, prostate specific antigen/${\alpha}1$-antichymotrypsin (PSA-ACT) complex, in which the ultrathin rGO sensing channel was simply formed by a uniform self-assembly of two-dimensional rGO nanosheets on aminated pattern generated by inkjet printing. Sensing characteristics of rGO-FET immunosensor showed the highly precise, reliable, and linear shift in the Dirac point with the analyte concentration of PSA-ACT complex and extremely low detection limit as low as 1 fg/ml. We further analyzed the charge doping mechanism, which is the change in the charge carrier in the rGO channel varying by the concentration of biomolecules. Amenability of solution-based scalable fabrication and extremely high performance may enable rGO-FET device as a versatile multiplexed diagnostic biosensor for disease biomarkers.

• The Research Journal of the Costume Culture
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• v.25 no.6
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• pp.741-756
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• 2017

The natural resources of Jeju are recognized as the new regional image of that clean island. Reflecting these trends, this study is initiated to develop a textile design with the motive of persimmon, a natural resource of Jeju, and to apply it to infant's and children's clothes. Its purpose is to highlight the image of persimmon, a traditional dye, as a regional signature for Jeju. Product development procedure included, understanding the use of persimmon for fashion products, analyzing Infants' and Children's designer collections over the last three seasons (focused on 2014S/S, 2015S/S, and 2016S/S), and surveying the Children's Clothes market for persimmon dyeing in Jeju. The conclusion was that, the natural resources of Jeju are highly valuable, and should be applied to textile design and apparel products for children. Utilizing Jeju persimmon was actively studied, but, the market for the Jeju persimmon natural - dyeing products is extremely limited. Moreover, the apparel products for infants and children represent old-fashioned styles, despite their higher prices. Therefore, using the formative characteristics of persimmon for each theme was suggested for development of patterns for textile design. Pattern designs were expressed using textured textile screen-printing, embroidery and $appliqu{\acute{e}}$ for infants' and children's clothes. In this study, a total of 10 items were prepared as apparel products for infants and children. All items were designed considering mix-and-match, potential, with each other or with regular mass-market products. These results are expected to contribute to highlighting the unique image of Jeju and to help promote fashion culture products.

• Korean Journal of Materials Research
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• v.19 no.8
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• pp.437-442
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• 2009

This paper describes an improved strategy for controlling the adhesion force using both the antiadhesion and adhesion layers for a successful large-area transfer process. An MPTMS (3-mercaptopropyltrimethoxysilane) monolayer as an adhesion layer for Au/Pd thin films was deposited on Si substrates by vapor self assembly monolayer (VSAM) method. Contact angle, surface energy, film thickness, friction force, and roughness were considered for finding the optimized conditions. The sputtered Au/Pd ($\sim$17 nm) layer on the PDMS stamp without the anti-adhesion layer showed poor transfer results due to the high adhesion between sputtered Au/Pd and PDMS. In order to reduce the adhesion between Au/Pd and PDMS, an anti-adhesion monolayer was coated on the PDMS stamp using FOTS (perfluorooctyltrichlorosilane) after $O_2$ plasma treatment. The transfer process with the anti-adhesion layer gave good transfer results over a large area (20 mm $\times$ 20 mm) without pattern loss or distortion. To investigate the applied pressure effect, the PDMS stamp was sandwiched after 90$^{\circ}$ rotation on the MPTMS-coated patterned Si substrate with 1-${\mu}m$ depth. The sputtered Au/Pd was transferred onto the contact area, making square metal patterns on the top of the patterned Si structures. Applying low pressure helped to remove voids and to make conformal contact; however, high pressure yielded irregular transfer results due to PDMS stamp deformation. One of key parameters to success of this transfer process is the controllability of the adhesion force between the stamp and the target substrate. This technique offers high reliability during the transfer process, which suggests a potential building method for future functional structures.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.56-59
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• 2011

The process conditions for high efficiency industrial crystalline Si solar cells with selective emitter were optimized. In the screen printed solar cells, the sheet resistance must be 50-60V/sq. because of metal contact resistance. But the low sheet resistance causes the increase of the recombination and blue response at the short wavelength. Therefore, the screen printed solar cells with homogeneous emitter have limitations of efficiency, and this means that the selective emitter must be used to improve cell efficiency. This work demonstrates the feasibility of a commercially available selective emitter process, based on screen printing and conventional diffusion process. Now, we improved cell efficiency from 18.29% to18.45% by transition of heavy emitter pattern and shallow emitter doping condition.

• Journal of Digital Convergence
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• v.11 no.11
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• pp.143-153
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• 2013

Big data is expected to bring forth enormous public good as well as economic opportunity. However there is ongoing concern about privacy not only from public authorities but also from private enterprises. Big data is suspected to aggravate the existing privacy battle ground by introducing new types of privacy risks such as privacy risk of behavioral pattern. On the other hand, big data is asserted to become a new way to by-pass tradition behavioral tracking such as cookies, DPIs, finger printing${\cdots}$ and etc. For it is not based on a targeted person. This paper is to find out if big data could contribute to catching out behavioral patterns of consumers without threatening or damaging their privacy. The difference between traditional behavioral tracking and big data analysis from the perspective of privacy will be discerned.

• Journal of the Korean Society of Costume
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• v.60 no.10
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• pp.100-117
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• 2010

This thesis has three main purposes: first, will show kinds, patterns, types, expression techniques of modern korean women's trimmings by every ten years. Second, it is to trace the effect of each decade on women's Hanbok trimming designs. Third, it will point out factors. that caused the change of modern Korean women's Hanbok trimming design patterns. Henceforth, there comes the result of the research and analysis. Trimming design patterns of modern women's Hanbok can be divided into three categories temporally: The first period of from 1910s to the first half of 1950s saw that design patterns did not changed much from traditional ones. It is because there were many catastrophes such as the invasion of Japanese Empire and Korean War. The compound design had expressed people's wish to earn many sons and babies at the end of Joseon Dynasty. But it turned to wishing luck for individuals affected by individualism and liberalism imported from the west. Realistic designs are the most frequently used and the least lines made up patterns. The second period of from the latter half of 1950s to 1970s saw that women wore their Jeogories and Chimas as suits. Screen printing technique enabled for various design patterns to come out. And the development of textile industry introduced various expression techniques such as making lace, meshing, flocking, burn-out etc cetera. The third period of 1980s saw that Hanbok became a kind of luxurious clothe as people's living standard rose. Hanbok again came into the spotlight, Hanbok designers came forward and their individualities are respected. The characteristic expression technique of grey-dying and geometric design patterns are more frequently used for the simple and modern beauty.

• Journal of IKEEE
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• v.25 no.4
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• pp.607-612
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• 2021

This paper presents a novel CPW-fed UWB monopole paper antenna made by paper and copper tape. Through the simulation, the optimized antenna design parameters were obtained, and an antenna having an omni-directional radiation pattern and a gain of 2.2 dBi or more in the UWB frequency band of 3.1-10.6 GHz was designed. The antenna was manufactured using general A4 paper and copper tape, and the measurement result satisfies the return loss of -10dB or less in the UWB frequency band and confirm that the return loss characteristic was maintained even when the antenna plane was bent by 3 mm in the longitudinal direction. The proposed antenna is a wearable device that can provide services in the UWB band, and can be manufactured inexpensively by printing it with a conductive print on paper. So it can be used as a wearable antenna for UWB communication in various application fields such as logistics and disposable terminals.

• Journal of IKEEE
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• v.26 no.2
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• pp.205-210
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• 2022

We demonstrated roll-to-roll microcontact printed (mCP) microlens array (MLA) to enhance the light extraction of organic light emitting diodes (OLEDs). The commercially provided microlens array is used as a template for polydimethylsiloxane (PDMS) roll stamp. The fluorinated film is formed on the PDMS roll stamp from fluorinated ink with low boiling point and printed onto the bottom side of the organic light emitting diode without high pressure and high thermal treatment. With optimized concentration of ink, the pattern which is almost identical to that of the template MLA was successfully printed. Due to the structure and low optical absorbance of microcontact printed MLA, the external quantum efficiency of OLED was improved by about 18%.