• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.286-287
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• 2012

Reset-first resistive switching mechanism based on reduction reaction in HfO2-x with oxygen drift-diffusion was studied. we first report that the indirect evidence of local filamentary conductive path formation in bulk HfO2 film with local TiOx region at Ti top electrode formed during forming process and presence of anion-migration at interface between electrode and HfO2 during resistive switching through high resolution transmission electron microscopy (HRTEM), electron disperse x-ray (EDX), and electron energy loss spectroscopy (EELS) mapping. Based on forming process mechanism, we expected that redox reaction from Ti/HfO2 to TiOx/HfO2-x was responsible for an increase of initial current with increasing the post-annealing process. First-reset resistive switching in above $350^{\circ}C$ annealed Ti/HfO2 film was exhibited and the redox phenomenon from Ti/HfO2 to TiOx/HfO2-x was observed with high angle annular dark field (HAADF) - scanning transmission electron microscopy (STEM), EDX and x-ray photoelectron spectroscopy. Therefore, we demonstrated that the migration of oxygen ions at interface region under external electrical bias contributed to bipolar resistive switching behavior.

• Journal of the Korean Graphic Arts Communication Society
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• v.29 no.3
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• pp.105-124
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• 2011

TFT-LCD consists of LCD panel on the top, circuit unit on the side and BLU on the bottom. The recent development issues of BLU-dependent TFT-LCD have been power consumption minimization, slimmerization and size maximization. As a result of this trend, LED is adopted as BLU instead of CCFL to increase brightness and to reduce thickness. In liquid crystal displays, the light efficiency is below 10% due to the loss of light in the path from a light source to an LCD panel and presence of absorptive polarizer. This low efficiency results in low brightness and high power consumption. One way to circumvent this situation is to use a reflective polarizer between backlight units and LCD panels. Since a nano-wire grid polarizer has been known as a reflective polarizer, an idea was proposed that it can be used for the enhancement of the brightness of LCD. The use of reflective polarizing film is increasing as edge type LED TV and 3D TV markets are growing. This study has been carried out to fabrication of the nano-wire grid polarizer(NWGP) and investigated the brightness enhancement of LCD through polarization recycling by placing a NWGP between an c and a backlight unit. NWGPs with a pitch of 200nm were fabricated using laser interference lithography and aluminum sputtering and wet etching. And The NWGP fabrication process was using by the UV imprinting and was applied to plastic PET film. In this case, the brightness of an LCD with NWGPs was 1.21 times higher than that without NWGPs due to polarization recycling.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.4
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• pp.1368-1389
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• 2014

Three-dimensional multiple-input multiple-output (3D MIMO) and large-scale MIMO are two promising technologies for upcoming high data rate wireless communications, since the inter-user interference can be reduced by exploiting antenna vertical gain and degree of freedom, respectively. In this paper, we derive the achievable sum rate of 3D MIMO systems employing zero-forcing (ZF) receivers, accounting for log-normal shadowing fading, path-loss and antenna gain. In particular, we consider the prevalent log-normal model and propose a novel closed-form lower bound on the achievable sum rate exploiting elevation features. Using the lower bound as a starting point, we pursue the "large-system" analysis and derive a closed-form expression when the number of antennas grows large for fixed average transmit power and fixed total transmit power schemes. We further model a high-building with several floors. Due to the floor height, different floors correspond to different elevation angles. Therefore, the asymptotic achievable sum rate performances for each floor and the whole building considering the elevation features are analyzed and the effects of tilt angle and user distribution for both horizontal and vertical dimensions are discussed. Finally, the relationship between the achievable sum rate and the number of users is investigated and the optimal number of users to maximize the sum rate performance is determined.

• Journal of Energy Engineering
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• v.24 no.4
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• pp.63-70
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• 2015

Crevices between window and window frame cause not only heat losses but also serve path to sound transmission and infiltration of fine dusts that are harmful to humans. There were many efforts in the past to eliminate these crevices but because of the windows' indispensable function of opening and closing, it was an unsolvable problem. In this study, a new type sliding window is developed by applying horizontally rolling wheels to implement a surface sealing which is excellent for enhancing air tightness. To evaluate the feasibility of the newly developed window, forces for opening and closing, durability and air tightness were testet according to Korean Testing Standards. Force for opening a 2000 N window is 30 N. It endured 100,000 cycles of opening and closing. Infiltration was $0.00m^3/(m^2h)$ for a pressure difference of 10 Pa. Since this window has few moving parts, it has favorable features of low cost and few breakdown.

• Journal of the Korean Geosynthetics Society
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• v.2 no.1
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• pp.47-55
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• 2003

The effects of fiber composition factors of 14 geotextiles which are thickness, porosity, fiber length and diameter etc. on the transmissivity were examined and in-plane permeability of geotextiles under thickness change, transmissivity, confined load were analyzed by the constitutive equations. And the effects of laminar structure on the permittivity of laminar geotextile composites which were manufactured with fiber packing densities were assessed. Transmissivities were increased with thickness of geotextiles and in-plane permeability coefficients were increased with porosity and fiber diameter. The effects of porosity were decreased with normal stress and slightly increased with fiber length. Transmissivities were increased with fiber diameter and showed same tendensy for the same fiber length. Permittivities of laminar geotextile composites were influenced by the waterhead loss in the inner interface and the connection shape of these composites to water path was interpreted as bell mouth type or soft flux pipe type.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.9A
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• pp.758-766
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• 2011

Cooperative communications are adopted as a promising solution to achieve high data rate over large areas in the future 40 wireless system and the relay station (RS) is the key concept in cooperative communications. However, most existing works in this area focus only on optimal RS selections. In addition, there are only few works consider another crucial issue: how many relay stations we need to place. Only when the number of relay stations is defined, the relay station selection can be performed well. In this paper we derive a formula which describes the impact of varying number of RS on end-to-end link throughput assuming a clustering scheme which is based on Voronoi tessellation. In addition to mathematical analysis on the feasibility of the formula, we also examine its performance through a set of simulations under the Erceg path loss model. Simulation results verify that the link throughput gain of our proposed scheme is promising.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.1
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• pp.14-19
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• 2016

In this paper, a wideband slot antenna with corrugated structure antenna is proposed. The proposed antenna consists of a ground plane with corrugated slot and microstrip feed-line. Even with a limited dimension of $70{\times}70{\times}1.6mm$, the proposed antenna has wide bandwidth due to the longer current path formed by the corrugated slot structure. Measured bandwidth(10 dB return loss) and fractional bandwidth of the proposed antenna are 2,180 MHz(2.5~4.68 GHz) and 60.7 % at the center frequency of 3.59 GHz. The proposed antenna has an omni-directional radiation pattern and measured gains and average efficiency were 3.48~5.83 and dBi, 81.55 %, respectively.

• Journal of the Korea Society of Computer and Information
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• v.11 no.5 s.43
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• pp.211-221
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• 2006

Manufacturing Execution System(MES) immediately enables users to share the information of systems industrywide, efficiently manages synthetic information with data collection through treating the data in a fast way, and helps their decision-making. MES for real-time information processing requires certain conditions such as data modeling of RFID, which has recently attracted attentions, and monitoring of each product unit from manufacture to sales. However, in the middle of processing the unit with a RFID tag, transponders(readers) can't often read the tag due to reader's malfunctions, intentional damages, loss and the circumstantial effects; for that reason, users are unable to confirm the location of the product unit. In this case, users cannot avoid tracing the path of units with uncertain clues. In this paper we suggest that the unique MES based on RFID and Bayesian Network can immediately track the product unit, and show how to evaluate it.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.906-911
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• 2008

Because the perimeter of buildings is strongly influenced by solar and the outdoor air temperature, the area has different environmental properties compared to the interior of a building, as in summer heat gain, and in winter heat loss. In particular, if the external wall is glass, the characteristics of the glass material make it pervious to outside conditions, thereby making big changes to the thermal environment. By combining shading device and the efficient exhaust system, an energy saving can be achieved compared to no air barrier systems. The simplified air barrier system is developed with the idea that energy could be conserved by carefully and effectively blowing out the air caught between the glass surface and the roller blind. The way it is configured is therefore by making the roller blind's air-path, and by placing the air output ducts in the most optimum positions. This simplified air barrier system will give improvement in the thermal environment of the parameter area that is strongly affected by solar and the outdoor condition.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.37
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• pp.277-327
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• 2008

This paper is to provide for an analysis on the trade adjustment assistance program and the Case study affected by international trade and FTA. The paper offers a legal study on analysis about Korea's Trade Adjustment Assistance Law for the Manufacturing Industries, USA's TAA. and Japan's law for Industry revival. In general, USA's TAA measures are defined as assistance actions for business enterprises, farmers and manufacturing industries workers. We exclude farmers and fishermen under Korea's Trade Adjustment Assistance Law for the Manufacturing Industries's business enterprises and workers, but we give them the systemic supports under korea's special assistance law for the farmers and fishermen and so on after FTA. Especially this focuses on the trade adjustment assistance case about both Korea's agriculture-farmer assistance from FTA and USA's TAA from workers in layoffs of trade-impacted communities. Korea has provided TAA to the sphere of agriculture after special legislation in Korea-Chile helping closed orchard, modernizing high quality producing facility for agriculture competition, producing superior fruit saplings, and constructing the distribution center in the producing district. But for US-Korea FTA and rapid increase of import by FTA expansion, we must prepare such indemnity systems for loss as cash benefit and wider aids for closed farm. The USA's TAA program targets manufacturing workers affected by international trade, who may have fewer transferable skills and face greater challenges to reemployment than other dislocated workers. A large majority sought some assistance from their one-stop center. Relatively small numbers chose to enroll in training, but those who did it often used this opportunity to chart a new career path. Finally, we learned the importance of education and discipline from USA cases. The fast and accurate information providing can raise efficiencies. The infrastructure can maximize the effect of TAA. The effective application would help us get over difficulties of TAA at hand.