• Spatial Information Research
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• v.18 no.4
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• pp.23-32
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• 2010

Water mains underground facilities are essential components to make up urban infrastructure. In order to manage these water mains underground facilities systematically and scientifically, GIS (Geographic Information System) had been constructed. For the sake of construction of GIS for water mains underground facilities, an exact underground detection and the construction of DB (Data Base) for buried water mains underground facilities should be preceded. In this study, in order to find out the ways to improve exact detection rate of data, the statistical analysis for the causes of detection raw degradation was done, and standardization methods of detection through a case study were suggested, When water mains underground facilities were measured, the detection of non-metallic water pipes was not carried out. The reason was that the results of detection was uncertain and detection was difficult because the assessment of public measurements was vulnerable. Moreover, due to the absence of standardized operating regulations for detection, systematic surveys weren't conducted. In this study, methods to standardize works over the detection of water mains underground facilities were presented so that we can improve the detection rate when we are doing that. As the proposals to improve detection rate, effective performance assessment over non-metallic pipes were presented, and related issues to supplement work regulations of public survey were described systematically.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.1
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• pp.171-184
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• 2010

In this work, we develop a novel channel power allocation method for the real-time multimedia over the wireless network environment. Since each frame has different effect on the user perceivable QoS, improving packet loss does not necessarily coincide with perceivable improvements in QoS. A new channel power control scheme is suggested based on the quantified importance of each frame in terms of user perceivable QoS. Dynamic programming formulation is used to obtain optimal transmit power which minimizes power consumption and maximizes user perceivable QoS simultaneously. The experiment is performed by using publicly available video clips. The performance is evaluated using network simulator version 2 (NS 2) and decoding engine is embedded at the client node, and calculated PSNR over the every frame transmitted. Through the semantics aware power allocation (SAPA) scheme, significant improvement on the QoS has been verified, which is the result of unequal protection to more important packets. SAPA scheme reduced the loss of I frame by upto 27% and reduced power consumption by upto 19% without degradation on the user perceivable QoS.

• Bulletin of the Korean Chemical Society
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• v.32 no.12
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• pp.4205-4209
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• 2011

The $Li_2Mn_{0.5}Fe_{0.5}SiO_4$ silicate was prepared by blending of $Li_2MnSiO_4$ and $Li_2FeSiO_4$ precursors with same molar ratio. The one of the silicates of $Li_2FeSiO_4$ is known as high capacitive up to ~330 mAh/g due to 2 mole electron exchange, and the other of $Li_2FeSiO_4$ has identical structure with $Li_2MnSiO_4$ and shows stable cycle with less capacity of ~170 mAh/g. The major drawback of silicate family is low electronic conductivity (3 orders of magnitude lower than $LiFePO_4$). To overcome this disadvantage, carbon composite of the silicate compound was prepared by sucrose mixing with silicate precursors and heat-treated in reducing atmosphere. The crystal structure and physical morphology of $Li_2Mn_{0.5}Fe_{0.5}SiO_4$ was investigated by X-ray diffraction, scanning electron microscopy, and high resolution transmission electron microscopy. The $Li_2Mn_{0.5}Fe_{0.5}SiO_4$/C nanocomposite has a maximum discharge capacity of 200 mAh/g, and 63% of its discharge capacity is retained after the tenth cycles. We have realized that more than 1 mole of electrons are exchanged in $Li_2Mn_{0.5}Fe_{0.5}SiO_4$. We have observed that $Li_2Mn_{0.5}Fe_{0.5}SiO_4$ is unstable structure upon first delithiation with structural collapse. High temperature cell performance result shows high capacity of discharge capacity (244 mAh/g) but it had poor capacity retention (50%) due to the accelerated structural degradation and related reaction.

• Journal of Digital Contents Society
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• v.19 no.8
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• pp.1603-1615
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• 2018

In order to achieve the low complexity and area, power in the design of Optical Image Stabilization (OIS) suitable for the smart phone, this paper presents the following design explorations, such as; optimization of gyroscope sampling rate, simple and accurate gyroscope filters, and reduced operating frequency of motion compensation, optimized bit width in ADC and DAC, evaluation of noise effects due to PWM driving. In experiments of gyroscope sampling frequencies, it is found that error values are unvaried in the frequency above 5KHz. The gyroscope filter is efficiently designed by combining the Fuzzy algorithm, to illustrate the reasonable compensation for the angle and phase errors. Further, in the PWM design, the power consumption of 2MHz driving is shown to decrease up to 50% with respect to the linear driving, and the imaging noises are reduced in the driving frequency above 2MHz driving frequency. The operating frequency could be reduced to 5KHz in controller and 10KHz in driver, respectively, in the motion compensation. For ADC and DAC, the optimized exploration experiments verify the minimum bit width of 11bits in ADC as well as 10bits in DAC without the performance degradation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.spc1
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• pp.211-215
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• 2005

Three curcuminoids [curcumin (CUR), demethoxycurcumin(DEM), bisdemethoxycurcu in (BIS)] are major yellow pigments in turmleric (Curcuma longa L.) root. Contents of curcuminoids in turmeric roots collected from 6 locations were analyzed using, high performance liquid chromatography (HPLC) equipped with reversed-phase column, an UV-Vis detector at 420nm, and eluted with a mixture of acetonitrile: $0.1\%$ acetic acid in water (50 : 50, v/v) as mobile phase. The stability of curcuminoid pigments in $80\%$ methanol extract solution were investigated during storage in a freezer at $-20^{\circ}C$, room temperature in the dark, and light condition. Calibration curves for the determination of curcuminoids were made with significant linearity $(r^2=0.999**)$. Average content of total curcuminoids was 171.5 mg/g, with 91.6 mg/g of CUR, 56.9 mg/g of DEM, and 23.0 mg/g of BIS. Amount of curcuminoids during storage in a freezer was almost not changed while those in room temperature wert reduced and rapid degradation appeared after 60 days. Within 90 days, about $50\%$ curcuminoid decreased in the dark and about $70\%$ in the light condition, indicating the decomposition of curcuminoid pigments followed under light and heat.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.5
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• pp.13-18
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• 2016

In Long Term Evolution-Advanced (LTE-A), small cell enhancement(SCE) has been developed as a cost-effective way of supporting exponentially increasing demand of wireless data services and satisfying the user quality of service(QoS). However, there are many problems such as the transmission rate and transmission quality degradation due to the dense and irregular distribution of a large number of small cells. In this paper, we propose a clustering based interference management scheme in dense small cell network. We divide the small cells into different clusters according to the reference signal received power(RSRP) from user equipment(UE). Within a cluster, an almost blank subframe(ABS) is implemented to mitigate interference between the small cells. In addition, we apply the power control to reduce the interference between the clusters. Simulation results show that proposed scheme can improve Signal to Interference plus Noise Ratio(SINR), throughput, and spectral efficiency of small cell users. Eventually, proposed scheme can improve overall cell performance.

• Journal of the Economic Geographical Society of Korea
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• v.4 no.2
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• pp.79-96
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• 2001

This paper introduces a new type of industrial cluster developed at the CBD of Seoul. Conventionally, clusters are said to be consisted of hi-tech, often If activities, manufacturing industries or artisan craft industries with increasing vertical integration and performance usually supported by venture capitals and favorable business infrastructure, not to mention governments', be it central or local, incentive plans. The study area, Cheonggyechon region has long been a traditional CBD frame of Seoul, Korea, being troubled by deterioration, traffic jams, and environmental degradation as most inner cities experience. Recently. this region has transformed to the most dynamic and productive area not by IT industries but by apparel and fashion activities. The study of the developmental trajectory and key characteristics for this kind of industrial cluster can give us insight both for the transition of inner city and for the cluster theory. This Paper firstly briefly Profiles the growth of the Cheonggyechon region over the past decade. It then shows the current spatial and business structure of the new industrial cluster, focusing on the fact that transactions costs are reduced, the creation and flow of information improves. and the local institutions are prone to be most responsive to the new cluster's specialized needs. The third section presents the key components of the customized production-distribution-shopping cluster development process, emphasizing the localized networking. social capital, spontaneous institutionalization of associational economic climate, and cultural economy based on place-specific inertia. The paper concludes with some comments about the prospects and perils of the new industrial cluster of Seoul.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.4
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• pp.381-391
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• 2010

In this paper, a novel frequency reconfigurable active array antenna(RAA) system, which can be reconfigurable for three reconfigurable frequency bands, is proposed by using commercial RF MEMS switches. The MEMS switch shows excellent insertion loss, linearity, as well as isolation. So, the system performance degradation of the reconfigurable system by using MEMS switches can be minimized. The proposed frequency reconfigurable active antenna system is consisted with the noble frequency reconfigurable front-end amplifiers(RFA) with the simple reconfigurable impedance matching circuits(RMC), reconfigurable antenna elements(RAE), as well as a reconfiguration control board(RCB) for MEMS switch control. The proposed RAA system can be reconfigurable for three frequency bands, 850 MHz, 1.9 GHz, and 3.4 GHz, with $2{\times}2$ array of the RAE having broadband printed dipole antenna topology. The validity of the proposed RFA as well as RAA is also presented with the experimental results of the fabricated systems.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.1 no.2
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• pp.125-136
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• 1997

Digestion of a municipal wastewater sludge by the anaerobic sequencing batch reactor(ASBR) was investigated to evaluate the performance of the ASBR process at a critical condition of high-solids-content feed. The reactors were operated at an HRT of 10 days with an equivalent loading rate of 0.8-1.5 gVS/L/d at $35^{\circ}C.$ The main conclusions drawn from this study were as follows: 1. Digestion of a municipal wastewater sludge was possible using the ASBR in spite of high concentration of settleable solids in the sludge. The ASBRS with 3- and 4-day cycle period showed almost identical high digestion performances. 2. No adverse effect on digestion stability was observed in the ASBRS in spite of withdrawal and replenishment of $30\%\;or\;40\%$ of liquid contents. A conventional anaerobic digester could be easily converted to the ASBR without any stability problem. 3. Flotation thickening occurred in thicken step of the ASBRS throughout steady state, and floating bed volume at the end of thicken period occupied about $70\%$ of the working volume of the reactor. Efficiency of flotation thickening in the ASBRS could be comparable to that of additional gravity thickening of a completely mixed digester. 4. Solids were accumulated rapidly in the ASBR during start-up period. Solids concentrations in the ASBRS were 2.6 times higher than that in the completely mixed control reactor at steady state. Dehydrogenase activity had a strong correlation with the solids concentration. Dehydrogenase activity of the digested sludge in the ASBR was 2.9 times higher than that of the sludge in the control reactor, and about 25 times higher than that of the subnatant in the ASBR. 5. Remarkable increase in equivalent gas production of $52\%$ was observed at the ASBRS compared with the control reactor in spite of similar Quality of clarified effluent from the ASBRS and control reactor. The increase in gas production from the ASBRS was believed to be combined results of accumulation of microorganisms, higher driving force applied, and additional long-term degradation of organics continuously accumulated.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.9
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• pp.1273-1279
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• 2016

The objectives of this study were to determine an optimal cultivation time for populations of yeast and lactic acid bacteria (LAB) co-cultured in fermented milk and effects of soybean meal fermented milk (SBMFM) supplementation on rumen degradability in beef cattle using nylon bag technique. The study on an optimal cultivation time for yeast and LAB growth in fermented milk was determined at 0, 4, 8, 24, 48, 72, and 96 h post-cultivation. After fermenting for 4 days, an optimal cultivation time of yeast and LAB in fermented milk was selected and used for making the SBMFM product to study nylon bag technique. Two ruminal fistulated beef cattle ($410{\pm}10kg$) were used to study on the effect of SBMFM supplementation (0%, 3%, and 5% of total concentrate substrate) on rumen degradability using in situ method at incubation times of 0, 2, 4, 6, 12, 24, 48, and 72 h according to a Completely randomized design. The results revealed that the highest yeast and LAB population culture in fermented milk was found at 72 h-post cultivation. From in situ study, the soluble fractions at time zero (a), potential degradability (a+b) and effective degradability of dry matter (EDDM) linearly (p<0.01) increased with the increasing supplemental levels and the highest was in the 5% SBMFM supplemented group. However, there was no effect of SBMFM supplement on insoluble degradability fractions (b) and rate of degradation (c). In conclusion, the optimal fermented time for fermented milk with yeast and LAB was at 72 h-post cultivation and supplementation of SBMFM at 5% of total concentrate substrate could improve rumen degradability of beef cattle. However, further research on effect of SBMFM on rumen ecology and production performance in meat and milk should be conducted using in vivo both digestion and feeding trials.