• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05c
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• pp.124-130
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• 2003

Zinc Oxide(ZnO) thin films on Si (100) substrate were deposited by RF magnetron sputter with changing sputtering conditions such as argon/oxygen gas ratios, RF power, and substrate temperature, chamber pressure and target-substrate distance. To analyze a crystallographic properties of the films, $\theta/2\theta$ mode X-ray diffraction, SEM, and AFM analyses. C-axis preferred orientation, resistivity. and surface roughness highly depended on $Ar/O_2$ gas ratios. The resistivity of ZnO thin films rapidly increased with increasing oxygen ratio and the resistivity value of $9{\times}10^7{\Omega}cm$ was obtained at a working pressure of 10 mTorr with $Ar/O_2$=50/50. The surface roughness was also improved with increasing oxygen ratio and the ZnO films deposited with $Ar/O_2$=50/50 showed the excellent roughness value of $28.7{\AA}$.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1190-1192
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• 2003

This paper presents a novel single-stage high frequency resonant inverter link type DC-DC converter using zero voltage switching with high input power factor. The proposed high frequency resonant converter integrates half-bridge boost rectifier as power factor corrector (PFC) and half-bridge resonant converter into a single stage. The input stage of the half-bridge boost rectifier is working in discontinuous conduction mode(DCM) with constant duty cycle and variable switching frequency. So that boost converter make the line current follow naturally the sinusoidal line voltage waveform. Experimental results have demonstrated the feasibility of the proposed DC-DC converter. This proposed converter will be able to be practically used as a power supply in various fields as induction heating applications, DC-DC converter etc.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.1
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• pp.81-88
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• 2007

In this paper, a new single-phase utility-interactive inverter system for residential power generation with fuel cell is proposed. The proposed inverter system is not only capable of working in both stand-alone and grid-connected mode, but also ensures smooth and automatic transfer between the two modes of operation. The proposed control method has little steady-state error and good transient response characteristic. Also, the control method can be implemented using low-cost, fixed point DSP since it has simpler structure, smaller amount of calculation, and smaller number of sensors. The controller for the proposed utility-interactive inverter system is described, and the validity is verified through simulation and experiment.

• The KIPS Transactions:PartC
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• v.13C no.4 s.107
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• pp.455-460
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• 2006

Currently, the IETF group is working on service differentiation in the Internet. However, in wireless environments such as Ad-hoc networks, where channel conditions are variable and bandwidth is scarce, the Internet differentiated services are suboptimal without lower layers' support. The IEEE 802.11 standard for Wireless LANs is the most widely used WLAN standard today. 1t has a mode of operation that can be used to provide service differentiation, but it has been shown to perform badly. In this paper, we present a new service differentiation scheme for support QoS in the wireless IEEE 802.11, which is based on a multiple queuing system to provide priority of user's flow. We simulate and analyze the performance of our algorithm and compare its performance with the original IEEE 802.11b protocol. Simulation results show that our approach increases overall throughput in the MAC layer.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.465-470
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• 2002

A novel phased array antenna system for space-borne polarimetric SAR is proposed and completed in this paper.The antenna system assures polarimetric and multi-mode capability of SAR. It has broadband, high polarization isolation and high port to port isolation. The antenna system is composed of broadband polarimetric microstrip antenna, T/R modules and multifunction beam controller nit. The polarimetric microstrip antenna has more than 100MHz bandwidth at L-band with -30dB polarization isolation and high port to port isolation. The microstrip element and T/R module's structure and characteristics, the subarray's performances measuring results are presented in detail in this paper. A design scheme on beam controller of the phased array antenna is also proposed and completed, which is based on Digital Signal Processing (DSP) chip -TMS320F206. This beam controller unit has small size and high reliability compared with general beam controller. In addition, the multifunction beam controller unit can acquire and then send the T/R module's working states to detection system in real time.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.295-298
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• 2005

High temperature deformation behavior of $\alpha\;and\;\beta$ phase of Ti-6Al-4V was investigated within the framework of a self-consistent approach at various temperature ranges. To examine the flow behavior of u-phase, Ti-7.0Al-1.5V alloy was used, whose chemical composition is close to that of the $\alpha$ phase in Ti-6Al-4V at hot working temperatures. The flow stress of $\beta$ phase was predicted by using self-consistent approach. The flow stress of $\alpha$ phase was higher than that of $\beta$ phase above $750^{\circ}C$, while the $\beta$ phase revealed higher flow stress than a phase at $650^{\circ}C$. It was found that the relative strength and strain rate ratio between $\alpha\;and\;\beta$ phase significantly varied with temperature. From this approach, the mode for grain matrix deformation was proposed as a mixed type of both iso-stress and iso-strain rate modes.

• ALGAE
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• v.28 no.2
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• pp.131-147
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• 2013

Major progress has been made in the past decade towards understanding of the biosynthesis of red carotenoid astaxanthin and its roles in stress response while exploiting microalgae-based astaxanthin as a potent antioxidant for human health and as a coloring agent for aquaculture applications. In this review, astaxanthin-producing green microalgae are briefly summarized with Haematococcus pluvialis and Chlorella zofingiensis recognized to be the most popular astaxanthin-producers. Two distinct pathways for astaxanthin synthesis along with associated cellular, physiological, and biochemical changes are elucidated using H. pluvialis and C. zofingiensis as the model systems. Interactions between astaxanthin biosynthesis and photosynthesis, fatty acid biosynthesis and enzymatic defense systems are described in the context of multiple lines of defense mechanisms working in concert against photooxidative stress. Major pros and cons of mass cultivation of H. pluvialis and C. zofingiensis in phototrophic, heterotrophic, and mixotrophic culture modes are analyzed. Recent progress in genetic engineering of plants and microalgae for astaxanthin production is presented. Future advancement in microalgal astaxanthin research will depend largely on genome sequencing of H. pluvialis and C. zofingiensis and genetic toolbox development. Continuous effort along the heterotrophic-phototrophic culture mode could lead to major expansion of the microalgal astaxanthin industry.

• Journal of Korea Society of Industrial Information Systems
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• v.13 no.2
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• pp.1-7
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• 2008

This paper presents a method to design a repetitive controller that is robust to variations in the system parameters. The uncertain parameters are specified probabilistically by their probability distribution functions. Instead of working with the distribution functions directly, the repetitive controller is designed from a set of models that are generated from the specified probability functions. With this multiple-model design approach, any number of uncertain parameters that follow any type of distribution functions can be treated. furthermore, the controller is derived by minimizing a frequency-domain based cost function that produces monotonic convergence of the tracking error as a function of repetition number. Numerical illustrations show how the proposed multiple-model design method produces a repetitive controller that is significantly more robust than an optimal repetitive controller designed from a single nominal model of the system.

• Journal of Fashion Business
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• v.6 no.3
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• pp.15-27
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• 2002

A uniform is generated in the course of confirming a singular mode of dress that is adopted by a community for a specific purpose. In particular, women's uniform has a close relations to their position in the community they belong to. And women's uniform has closely been associated with finding ways into their communities over the centuries, and is part of women's development process. Women's history of using organized uniforms has not been longer than men's. Their realm of activities began to be enlarged due to the World War, and women's uniform has gradually settled down and moved toward diversity. The origin of many uniforms worn by today's women can be traced back to the end of the last century, and this fact indicates that women started to find their ways into many new fields at that time. There has been a lot of changes until current women's uniforms come out. It's intended in this study to contribute to designing more creative and productive women's uniform, by taking a careful look at typical early uniforms for service personnels, nannies, nurses and soldiers that are an indication of their work and working environment.

• Journal of Fashion Business
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• v.4 no.1
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• pp.97-111
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• 2000

The term Japonism was coined in France where the predilection for Japanese art forms was immediately apparent, influencing Impressionism, Symbolism, Post-Impressionism, and later the Art Nouveau movement, all of which reflect aspects of Japanese art adapted to Western style. The 1968 May Revolution in Paris changed traditional thinking and shifted the center of fashion of the 1970's from haute couture to pret-a porter. At about the same time, having recovered from the destruction of war, Japan started to emerge as a leading economic force. The Japanese clothing designers, who were inspired by their own traditions, began to present their collections in the West. Hanae Mori's dresses with Japanese floral motifs were the first to appear. The West was captivated by the colorfully layered clothing of Kenzo Takada inspired by peasant and working class kimonos. And Issey Miyake was acclaimed for his innovative concepts of ‘one piece of cloth'. In the 1980s Rei Kawakubo and Yohji Yamamoto achieved recognition with their deconstructivist and minimalist approaches to fashion. The clothing proposed by these Japanese designers has transcended not only national and sexual boundaries, but also those of accepted materials in which to work. These designs suggest new possibilities and are unrestricted by preconceived ideas of kimono or of Western clothing. The emergence of Japanese designers as a powerful creative force in the late twentieth century has created a new dimension to the term Japonism in fashion. By integrating the clothing traditions of the West and Japan, while at the same time departing from them, a new international genre of clothing has been created.