• Korean Journal of Medicinal Crop Science
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• v.10 no.3
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• pp.200-205
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• 2002

Platycodin D was isolated from n-butanol extract of Platycodi radix(Platycodon grandiflorum and identified by the spectroscopic analysis using $^1H$ and $^{13}C$ NMR techniques. A new method of analysis of platycodin D by high performance liquid chromatography(HPLC) was established using a reversed phase system with YMC-Pack ODS-AM( 250 X 4.6 mm) column and 30% acetonitrile as a mobile phase. Evaporative light scattering detector was used as detector. The kinds of extraction solvents and methods were examined to determine the efficient extraction condition and HPLC analysis was carried out to establish the optimum drying condition for the root of Platycodon grandiflorum. The contents of Platycodin D was highest as 0.083% when platycodon roots were dried at $60^{\circ}C$ using dry oven.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.7B
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• pp.1384-1392
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• 1999

A high compression rate is required to transmit video sequences over low bit rate networks such as low bit rate communication channels. When highly compressed videos are transmitted over mobile channels of high error rate, bitstreams corrupted by channel errors are not only difficult to be decoded, but also have fatal effects on the other parts of the bitstreams. In this Paper, we propose an error concealment algorithm for recovering the blocks which can not be decoded due to damaged bitstreams. The proposed error concealment algorithm recovers the damaged blocks using the information of adjacent blocks which are correctly decoded. In the proposed algorithm, the motion vector of the damaged block is estimated using the overlapped block motion compensation(OBMC) and block boundary matching(BBM) techniques. Experiment results show that the proposed algorithm exhibits better performance in PSNR than existing error concealment methods.

• Journal of the Korea Convergence Society
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• v.11 no.10
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• pp.81-88
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• 2020

This purpose of this study is to develop content that enables repetitive carving practice of the maxillary right central incisor (MRCI) based on augmented reality (AR). For a step-by-step practice of achieving the tooth shape, after creation of the storyboard from the square box shape in step 1 to the completed MRCI block in step 16, three-dimensional (3D) modeling data reflecting the characteristics of the mesial, distal, lingual, and labial surface of the MRCI were generated. An application was built in which 3D modeling data were output on the screen of the learner's mobile device, and image markers suitable for 3D modeling in steps 1 to 16 of the MRCI model were respectively generated. Using this information, the learner could carve a high-quality MRCI by repeatedly performing the tooth shape carving exercises. With AR, we intend to contribute to improved tooth morphology carving skills by linking the theory and practical techniques for a beginners in dentistry.

• Journal of Communications and Networks
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• v.18 no.5
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• pp.837-845
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• 2016

Providing a customer with tailored location-based services (LBSs) is a fundamental problem. For location-estimation techniques with radio-based measurements, LBS applications are widely available for mobile devices (MDs), such as smartphones, enabling users to run multi-task applications. LBS information not only enables obtaining the current location of an MD but also provides real-time push-pull communication service. For indoor environments, localization technologies based on radio frequency (RF) pattern-matching approaches are accurate and commonly used. However, to survey radio information for pattern-matching approaches, a considerable amount of time and work is spent in indoor environments. Consequently, in order to reduce the system-deployment cost and computing complexity, this article proposes an indoor positioning approach, which involves using Asus Xtion to facilitate capturing RF signals during an offline site survey. The depth information obtained using Asus Xtion is utilized to estimate the locations and predict the received signal strength (RF information) at uncertain locations. The proposed approach effectively reduces not only the time and work costs but also the computing complexity involved in determining the orientation and RF during the online positioning phase by estimating the user's location by using a smartphone. The experimental results demonstrated that more than 78% of time was saved, and the number of samples acquired using the proposed method during the offline phase was twice as much as that acquired using the conventional method. For the online phase, the location estimates have error distances of less than 2.67 m. Therefore, the proposed approach is beneficial for use in various LBS applications.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.1
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• pp.9-15
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• 2008

Mokumegane is one of the sophisticated metal craft techniques enabling wood grain surface effect. To embody the mokumegane, an ingot of well-bonded stacked metal plates has been required. Traditionally prepared mokumegane ingots were bonded using charcoal which enables reduction atmosphere, but sometimes end up with collapse of bonding interface due to the lack of reliable process control. We proposed a systematic vacuum direct bonding process for ingots. First, we confirmed copper//copper homogeneous plate bonding at $900^{\circ}C$ by applying uniaxial press of 2.5kg. We observed 80min required to obtain 90%-bonding ratio and the diffusion coefficient would be enhanced up to 100 times due to surface effect. Second, by considering enhanced diffusion behavior, we also obtained optimum bonding condition in copper/silver heterogeneous plates that ensures 90%-bonding ratio at $700^{\circ}C$ for 10min with apply uniaxial press. A 7-layered copper/silver ingot is prepared successfully, and eventually the prototype mokumegane cases for mobile phone were fabricated with these ingot.

• Journal of Broadcast Engineering
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• v.12 no.2
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• pp.120-127
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• 2007

In this paper, we describe a new 1/4 rate robust modulation techniques for Enhanced-x VSB system which is fully backward compatible with ATSC 8-VSB standard. 1/4 rate mode Enhanced-xVSB system provides broadcasters with a wide choice of trade-offs of data rate vs amount of robustness of enhanced data for pedestrian/mobile services. Lab test results of proposed Enhanced-x VSB 1/4 rate mode robust stream are a significantly improved multipath as well as AWGN reception performance for Enhanced-x VSB receiver. We suggest an Enhanced-x VSB terrestrial broadcasting system for ATSC HDTV and pedestrian/portable TV simultaneous broadcasting service providing.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.1
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• pp.58-63
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• 2010

In this paper, we proposed a wearable respiration measurement system with textile capacitive pressure sensor. Belt typed textile capacitive pressure sensor approach of respiration measurement, from which respiration signatures and rates can be derived in real-time for long-term monitoring, are presented. Belt typed textile capacitive pressure sensor has been developed for this measurement system. the distance change of two plates by the pressure of motion has been used for the respiration measurement in chest area. Respiration rates measured with the textile capacitive pressure sensor was compared with standard techniques on 8 human subjects. Accurate measurement of respiration rate with developed sensor system is shown. The data from the method comparison study is used to confirm theoretical estimates of change in capacitance by the distance change. The current version of respiratory rate detection system using textile capacitive pressure sensor can successfully measure respiration rate. It showed upper limit agreement of $3.7997{\times}10^{-7}$ RPM, and lower limit of agreement of $-3.8428{\times}10^{-7}$ RPM in Bland-Altman plot. From all subject, high correlation were shown(p<0.0001). The proposed measurement method could be used to monitor unconscious persons, avoiding the need to apply electrodes to the directly skin or other sensors in the correct position and to wire the subject to the monitor. Monitoring respiration using textile capacitive pressure sensor offers a promising possibility of convenient measurement of respiration rates. Especially, this technology offers a potentially inexpensive implementation that could extend applications to consumer home-healthcare and mobile-healthcare products. Further advances in the sensor design, system design and signal processing can increase the range and quality of the rate-finding, broadening the potential application areas of this technology.

• Korean Journal of Environmental Agriculture
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• v.25 no.4
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• pp.359-364
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• 2006

Reversed-phase high-performance liquid chromatography (HPLC) techniques were developed to quantify abamectin (ABM) in paprika (Capsicum annum). Separation was achieved on a $C_{18}$ ODS column with a mobile phase of acetonitrile/water (96/4, v/v) mixture in an isocratic elution at the flow tate of 1.2 mL/min for avermectins (AVMs). The retention times were 8.0 and 9.7mins for AVM $B_{lb}$ and AVM $B_{1a}$, respectively. Residual AVMs (sum of AVM $B_{1a}$, AVM $B_{1b}$ and 8,9-Z-AVM $B_{1a}$) in the vegetable were extracted with acetonitrile, and the silica solid-phase extraction cartridges were used to purify the extract. AVMs were derivatized using trifluoroacetic acid and 1-methylimidazole, and the derivatives were determined with a fluorescence detector (excitation at 365 nm and emission at 470 nm). High and consistent recoveries, ranging from 93% to 115%, were obtained for AVM $B_{1a}$ and 8, 9-Z-AVM $B_{1a}$ at fortified levels of $20{\mu}g/kg\;and\;200{\mu}g/kg$ for paprika. The limit of quantitation (LOQ) was $2{\mu}g/kg$. The residual levels of AVMs in paprika in a field experiment from one day to seven days after the last application decreased from 18.40 to $7.59{\mu}g/kg$. The half-life $(T_{1/2})$ of AVMs in paprika was 1.47 days.

• Journal of Broadcast Engineering
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• v.15 no.6
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• pp.749-756
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• 2010

The signal space diversity is one of the promising transmission techniques in next generation mobile TV service. However, DVB-T2 does not consider the multiple antennas (MIMO) so that the cyclic Q-delay method, a component interleaver in DVB-T2, causes a critical issue in detecting symbols at the receiver side by increasing the inter-symbol dependency. To solve this problem, the component-swapping technique is proposed, which limits the inter-symbol dependency in order to reduce detection complexity. In this paper, the achievable gain of a component-swapping technique combined with 16K LDPC code defined in DVB-T2 is evaluated by computer simulations. From the results, the gain is confirmed in terms of BER and receive complexity compared to legacy component interleaver methods.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.129-130
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• 2018

Big data analysis is a technique for effectively analyzing unstructured data such as the Internet, social network services, web documents generated in the mobile environment, e-mail, and social data, as well as well formed structured data in a database. The most big data analysis techniques are data mining, machine learning, natural language processing, and pattern recognition, which were used in existing statistics and computer science. Global research institutes have identified analysis of big data as the most noteworthy new technology since 2011. Therefore, companies in most industries are making efforts to create new value through the application of big data. In this study, we analyzed using the Social Matrics which a big data analysis tool of Daum communications. We analyzed public perceptions of "Artificial Intelligence" keyword, one month as of May 19, 2018. The results of the big data analysis are as follows. First, the 1st related search keyword of the keyword of the "Artificial Intelligence" has been found to be technology (4,122). This study suggests theoretical implications based on the results.