• Journal of Korean society of Dental Hygiene
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• v.19 no.5
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• pp.859-871
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• 2019

Objectives: The present study aimed to evaluate the usability, quality, and usefulness of the mobile application, CAMBRA-kids, for caries management in preschoolers. Methods: Ninety-one caregivers and preschoolers participated in the user evaluation of CAMBRA-kids. The evaluators assessed the usability, quality, and usefulness of CAMBRA-kids. The collected data were analyzed using R studio 1.2.1335 for Windows (RStudio Inc. 2018, Boston, MA, USA). The evaluations for usability, quality, and usefulness were analyzed with descriptive statistics, Kruskal-Wallis rank sum test, and Wilcoxon rank sum test. Results: On user evaluation, the quality and usefulness of the application scored >3 points, and majority of the users rated the quality and usefulness of the application as high. The quality of the application's system was the highest at 3.68 points, and the actual usage of the application was the lowest at 3.10 points. The application had the highest technological aspect score of 3.20, whereas the content related to oral health information had the lowest score of 3.10/5. Although the application showed no statistically significant differences in the quality and usefulness according to general characteristics, there was a statistically significant difference (p<0.05) between the two when compared between the caries risk group. For all items, the protector of the high-risk group evaluated the quality and usefulness of the application highly. The moderate risk group gave the lowest evaluation score for the application's quality and usefulness. The usability score of the application, according to the user version of the mobile application rating scale (uMARS), was 3.25, and the average engagement score was 2.82 (56.31%). The highest subscale score was 3.63. Conclusions: In this study, we found suitable quality, usability, and usefulness of the mobile application, CAMBRA-kids. In future, the use of this application will contribute to the prevention of dental caries among preschoolers.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.7 no.2
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• pp.27-34
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• 2013

Most of existing biomedical signal measurement devices measure and evaluate biomedical signal only in a single device. Also, even if the device is multi-functional, those biomedical signals can be measured by selection of the user. In this paper, we implemented wristband-style biomedical signal measurement device for u-healthcare system to solve the problem above. Implemented device uses 4 infrared sensors to measure the pulse, 2 electrodes to measure the skin conductivity, and 3-axis accelerometer to measure momentum. Also, we propose a communication packet frame for transmitting biomedical signal data to PC or mobile device, using Zigbee. Studies show that our device has the error rate of less than twice for pulse measurement, 85.6%, 84.7% reliability for momentum measurement, and the skin conductivity has changed according to the user's physical status.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.11a
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• pp.1151-1153
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• 2007

P2P 및 Mobile Network, Reputations System 등의 분산 시스템은 sybil attack 에 노출되어 있다. sybil attack 은 한 명의 사용자가 다수의 식별자를 가진 것으로 위장하여 시스템 내에서 마치 실제 다수의 사용자인 양 시스템을 악용하는 공격방법이다. sybil attack 을 막기 위한 다양한 노력이 진행되었고, 최근에 SybilGuard 라는 social network 를 이용한 방어 방법이 제시되었다. SybilGuard 는 악의적인 사용자를 막기 위하여, Random Walk 의 변형이면서 결정적인 경로의 특징을 가지는 임의경로(Random Route)를 사용하여 악의적인 사용자의 sybil attack 을 방어한다. SybilGuard 는 sybil node 의 개수를 제한하고, 이들을 하나의 동일한 그룹으로 분류할 수 있도록 하여 시스템 내에서 가짜 식별자의 개수를 제한한다. 이를 위해 각 노드가 시스템에 돌어올 때 Verifier(V)노드가 이들 노드를 확인하게 되는데, 이를 위해 시스템 내의 선한 노드(Honest Node)를 사용하여 이들을 확인한다. 이 때, honest node 들은 verifier 의 요청에 따라 확인요청을 수행하게 되는데, social network 의 특성상 몇몇 노드들은 사회적인 명망으로 매우 큰 링크수를 가지게 될 것이며, 따라서 이들 노드들이 처리해야할 요청의 양이 매우 많아지게 될 것이다. 따라서 이들 honest node 들 간에 로드분포를 균등하게 하는 것이 요구되며, 이 논문에서는 부하 조절을 하기 위한 기법을 제시하고, 이들을 평가한다.

• Information Systems Review
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• v.22 no.3
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• pp.15-30
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• 2020

In the real estate industry, the latest changes in the Fourth Industrial Revolution, such as big data analytics, machine learning, and VR (virtual reality), combine to bring about industry change. Proptech is a new term combining properties and technology. This study aims to derive and analyze from a comprehensive perspective the quality factors (systems, services, interfaces, information) for mobile real estate brokerage services that are well known and used in the domestic market. The surveys in this study were conducted online and offline and a total of 161 samples were used for statistical analysis. As a result, all hypotheses were approved to except system quality and service quality. The results show that the domestic proptech companies who are mostly focused on real estate brokerage services, peer-to-peer lending, advertising platforms and apartments need to grow in various fields of proptech business of other countries including Europe, USA and China.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.3
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• pp.227-247
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• 2015

An X-band $8{\times}16$ dual-polarized active phased array antenna system has been implemented based on the substrate integrated waveguide(SIW) technology having low propagation loss, complete EM shielding, and high power handling characteristics. Compared with the microstrip case, 1 dB less is the measured insertion loss(0.65 dB) of the 16-way SIW power distribution network and doubled(3 dB improved) is the measured radiation efficiency(73 %) of the SIW sub-array($1{\times}16$) antenna element. These significant improvements of the power division loss and the radiation efficiency using the SIW, save more than 30 % of the total power consumption, in the active phased array antenna systems, through substantial reduction of the maximum output power(P1 dB) of the high power amplifiers. Using the X-band $8{\times}16$ dual-polarized active phased array antenna system fabricated by the SIW technology, the main radiation beam has been steered by 0, 5, 9, and 18 degrees in the accuracy of 2 degree maximum deviation by simply generating the theoretical control vectors. Performing thermal cycle and vacuum tests, we have found that the SIW array antenna system be eligible for the space environment qualification. We expect that the high efficiency SIW array antenna system be very effective for high performance radar systems, massive MIMO for 5G mobile systems, and various millimeter-wave systems(60 GHz WPAN, 77 GHz automotive radars, high speed digital transmission systems).

• Bulletin of the Korean Chemical Society
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• v.34 no.6
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• pp.1783-1790
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• 2013

A simultaneous analytical method has been developed for the fluorimetric determination of haloacetonitriles (HANs) [dichloroacetonitrile (DCAN), trichloroacetonitrile (TCAN), dibromoacetonitrile (DBAN), haloacetamides [dichloroacetamide (DCAD), and trichloroacetamde (TCAD)] in drinking water by using the combined on-line perconcentration/reversed phase liquid chromatography (RPLC)-postcolumn detection system. This on-line perconcentration system was achieved by employing a precolumn packed with a commercial solid phase extraction (SPE) sorbent for the enrichment and purification of the target analytes. The haloacetonitriles and haloacetamides were separated on CN analytical column in a 7.5% methanol-0.02 M phosphate buffered mobile phase at pH 3. The column effluents were reacted with postcolumn reagents of ophthaldialdehyde (OPA) and sulfite ion at pH 11.5, to produce a highly fluorescent isoindole fluorophore, which were measured with a fluorescence detector. Under the optimized conditions for RPLC and the postcolumn derivatization system all of the coefficient of determination of the standard calibration curves for the target analytes were over 0.99 and had a linear range from 5 to 100 ${\mu}g/L$. The detection limits showed 1.6 ${\mu}g/L$ for DCAD, 0.1 ${\mu}g/L$ for TCAD, 0.6 ${\mu}g/L$ for DCAN, 1.6 ${\mu}g/L$ for TCAN and 1 ${\mu}g/L$ for DBAN, and the recoveries were ranged from 64 to 99% except for DCAD with precisions less than 4.9% in distilled water, and from 72(${\pm}4%$) to 116%(${\pm}2%$) in tap water.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.447-448
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• 2007

Product development is consisting by trend that accommodate almost function digital cam in camera phone that can speak of Mobile appliance, and competition about number of elemental area of image sensor is consisting for market prior occupation between these. Propose in this research and small size camera phone self-focusing adjustment actuator that do city manufacture is similar with general storehouse pickup actuator drive way, but selected in cylindrical to reduce space that lens holder occupies because there is restriction loading of lens and space enemy. Target number of research established that execute drive displacement more than $600{\mu}m$ in 2.75V that is house voltage that is used in Mobile device that is general. Also, described about maximum transfer displacement characteristic, displacement response characteristic, hysteresis, response characteristic, smallest transfer step characteristic, actuator's drive characteristic that is manufactured to examination item of maximum consumption electric power by special quality estimation system that apply laser displacement sensor that produce itself to evaluate city manufactured actuator's special quality.

• KSBB Journal
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• v.18 no.2
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• pp.100-106
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• 2003

An on-line frontal analysis HPLC system was developed to determine the unbound concentration of (S)-perillyl alcohol, an potential anti-cancer agent, in human serum albumin (HSA) solution, The analysis was performed on a Develosil 100 Diol 5 (10 cm x 4.6 mm I.D.) high-performance frontal analysis (HPFA) column. Sodium phosphate solution was used as the mobile phase (pH 7.4, ionic strength 0.17) at a flow rate of 1 $m\ell$/min. UV wavelength was set at 205 nm. A injection volume of 600${mu}ell$ was chosen to ensure the compound eluted formed a zonal peak with a plateau. By Scatchard analysis, it was found that the binding constant(K) and binding number(n) of (S)-perillyl alcohol to molecular HSA were 2.05 x $10^6$ [$M{-1}$], 0.00428, respectively.

• Proceedings of The KACE
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• 2017.08a
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• pp.231-234
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• 2017

4차 산업혁명 시대에 접어드는 중심에 살고 있는 청소년들에게 스마트미디어는 삶의 가장 중요한 일부분이다. 미래창조과학부에서 발표한 2016년 조사에서 만 6세 이상 85%(2015년 대비 2.5%p${\uparrow}$)가 스마트 기기를 보유하고 있는 것으로 나타났다. 스마트기기의 보유율 증가는 게임 플랫폼으로 접근성이 높아지는 것을 의미하고 모바일 게임에 대한 과몰입 위험도가 커진다. 많은 연구와 논쟁이 이루어지는 온라인 게임에 대한 과몰입 대비에 비해 모바일 게임 과몰입 대책은 전무한 실정이다. 본 연구에서는 게임 과몰입에 가장 취약한 중학생을 대상으로 모바일 게임 제어 시스템을 통해 학생들이 자기 주도적으로 모바일 게임 과몰입에서 벗어날 수 있게 유도하였다. 학생들이 해당 시스템을 평상시에 활용했을 때 효율성과 실제 구현에 있어 고려해야 할 사항에 대해 알아보고자 한다.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.4
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• pp.592-596
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• 2009

DAFC(direct alcohol fuel cell) takes the same structure and operational principle with PEMFC(Proton exchange membrane fuel cell). However, DAFC, which uses liquid alcohol instead of hydrogen as fuel, is able to be used as a portable power for small-scaled electronic devices such as MP3, PMP, and mobile phone because alcohol is quite convenient steady-state compound to carry and store it. This paper presents the OCV(open circuit voltage) characteristics of the cases which are alcohol species and different weight rate of ethanol, respectively. The OCV of methanol fuel cell is slightly higher 0.2V than ethanol one, and 8% wt. rate ethanol is rated as the most appropriate fuel for DAFC.