• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.691-693
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• 2017

A novel structure of fast locking phase locked loop (PLL) with time difference detector and Lock status indicator (LSI) is proposed in this paper. Fast locking time is achieved using LSI. It has been simulated and proved by HSPICE in a CMOS $0.18{\mu}m$ 1.8V process.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.697-699
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• 2017

A novel structure of phase locked loop (PLL) which has small size with D Flip-Flop and sub charge pump has been proposed. The area of loop filter usually occupying the larger portion of the chip is minimized using a single small capacitor. It has been simulated and proved by HSPICE in a CMOS $0.18{\mu}m$ 1.8V process.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.2042-2043
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• 2007

고압회전기의 운전중 부분방전을 효과적으로 측정하고 진단하기위해 고정자 권선과 슬롯사이에 취부 되는 방향성 결합기형태의 부분방전센서가 일부 사용되고 있다. 기존 결합기형 센서는 마이크로스트립 등의 전송선로 타입으로, 센서 출력 단자의 효과적인 매칭을 목표로 설계되었으나, 센싱도체의 폭이 좁아 권선으로부터 효과적인 커플링이 힘들다. 본 논문에서는 고정자 권선 및 슬롯 구조의 전계분포 계산결과를 바탕으로 부분방전 신호 측정에 효과적인 형태의 센서를 설계하였다. 제작된 센서를 실제와 동일한 고정자 권선 및 슬롯 구조에서 타 센서와 비교하여 성능을 시험한 결과, 기존 마이크로스트립타입의 센서와 상용센서에 비해 좋은 감도를 가지는 것으로 나타났다.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1065-1067
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• 2005

본 논문은 기존의 가스차단기와는 다른 차단동작을 가지는 새로운 형태의 가스차단기에 대한 특징을 검토한 것이다. 기존의 차단기에서 움직이던 가동부가 고정되고, 반대로 고정부이던 피스톤이 움직인다. 또한 기존 차단기의 고정부였던 고정 아크접점에 MDDM(Motor direct drive mechanism)을 채용하고, 반대편에 피스톤과 연결되는 소형 유압식 조작기를 설치함으로서 양방향 차단기(dual motion circuit breaker)를 구현하였다. 국내에서는 처음으로 MDDM을 실제 차단기에 적용한 사례로 판단되며, 기본 차단동자특성을 분석하여 향후 초고압 차단기에 적용할 수 있는 가능성을 검토하였다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.1
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• pp.27-41
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• 2011

This research proposes new tram signal coordination model, called MAXBAND MILP-Tram for a passive tram signal priority strategy. The proposed model was formulated based on the MAXBAND model that was a traditional arterial signal optimization model. The model could calculate the bandwidth solutions for both general-purpose-lane traffic and median-tram-lane traffic. Lower progression speed are applied for the tram traffic considering lower running speed and dwell time at the stations. A phase sequence procedure determines the green times and left-turn phase sequences for tram traffic in median tram lane. To estimate the performance of the MILP-Tram model, the control delay of trams were estimated using the micro simulation model, VISSIM. The analysis results showed 57 percent decrease of the tram compared to the conventional signal timing model. The delay for car, however, increased 18 percent. The sensitivity analysis indicated that the passive tram signal priority strategy using the offset and phase sequence optimization was effective in reducing the person delay under the congested traffic condition.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.4
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• pp.446-452
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• 2008

This study was conducted to research the biosorption characteristics using algae, Spirulina platensis, for the removal of Pb and Cu ions in wastewater. Both of free algal cell and immobilized algae by Ca-alginate were used as bioadsorbent, and experiment was proceed in batch reactor for Pb and Cu ions removal, respectively. In the biosorption of Pb and Cu ions by free Spirulina platensis cell, the adsorption equilibrium reached within 20 minute. The higher adsorbed amount of Pb and Cu was shown as increasing of initial concentration of Pb and Cu, and pH of solution, respectively, and the optimum pH was 4.5$\sim$5.0. Under the conditions of initial concentration of Pb or Cu are 200 mg/L, the maximum amounts of Pb and Cu adsorbed to the unit weight of Spirulina platensis were 86.43 and 57.02 mg/g, respectively, and these values were 1.94 and 1.48 times higher than those of activated carbon under same conditions, respectively. The biosorption kinetics of Pb and Cu ions by free Spirulina platensis cell fitted very well to the Freundlich and Langmuir isotherm. The maximum amount of Pb or Cu adsorbed to the unit mass of adsorbent by the Langmuir isotherm($q_{max}$) represented as 95.24 and 62.50 mg/g, respectively. The FT-IR results of free Spirulina platensis biomass showed that biomass has different functional groups and these functional groups are able to react with metal ions in aqueous solution. In the biosorption of Pb and Cu ions by Ca-alginate immobilized algae Spirulina platensis, the adsorption equilibrium reached within 40 min. and observed a little diffusion limitation differed from the free algal cell adsorption.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.1
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• pp.93-98
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• 2020

Lesch-Nyhan syndrome is a rare X-linked, recessively inherited disorder of purine metabolism, caused by complete absence of the enzyme hypoxanthine-guanine phosphoribosyl transferase. This syndrome is characterized by 3 major features: neurological dysfunction, hyperuricemia, and cognitive and behavioral disturbances (e.g., self-mutilation, which begins at 2 to 3 years of age). Uncontrollable self-mutilation begins with biting of the perioral tissues and extends into patterns such as finger biting and head hitting. This report describes the case of a 31-month-old boy who was diagnosed with Lesch-Nyhan syndrome with severe lip injuries caused by self-mutilative behaviors. The behaviors were blocked with a semi-fixed lip bumper for a short period. The device was applied to the patient on the day of the visit without the requirement for an oral impression. It was easy to manage oral hygiene and adjust the device because it was detachable by clinicians and guardians. Therefore, a semi-fixed lip bumper may be useful as an interim appliance to block selfmutilative behaviors in children with Lesch-Nyhan syndrome.

• KSBB Journal
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• v.11 no.1
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• pp.22-29
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• 1996

Immobilized bioprocess was carried out for continuous production of cyclosporin A (CyA) produced intracellularly as a secondary metabolite by a filamentous fungus, Tolypocladium inflatum. Immobilization procedure for entrapping conidiospores of the producer was significantly simplified by use of a modified immobilization technique. A newly-designed immobilized perfusion reactor system (IPRS) showed good process benefits as demonstrated by the role of the high density immobilized cells as an efficient biomass generator, continuously supplying highly active CyA-producing free cells (1.0g/$\ell$/hr) even at very high dilution rate ($0.1hr^{-1}$). IPRS bioprocess was possible since efficient decantor system developed in our laboratory separated the sloughed-off free cells from the immobilized biomass effectively, thus overcoming wash-out phenomenon frequently encountered in continuous free cell cultures. Furthermore the released-free cells remaining in the bulk solution did not appear to cause substrate mass transfer limitation which was often experienced in suspended mycelial fungal cell fermentations. The primary reason for this was that the suspension broth of the IPRS mainly consisted of roundshaped short mycelial fragments and conidiospores, still remaining Newtonian even at high cell density. In parallel with IPRS bioprocess development, other key factors to be considered necessarily for significant increase in CyA productivity would be strain improvement and medium optimization for the immobilized cells.

• The korean journal of orthodontics
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• v.40 no.5
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• pp.325-333
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• 2010

Objective: The aim of this study was to illustrate the circumferential comfortable retainer (CCR) as a removable maxillary retainer with good potential patient compliance and to evaluate the discomfort of the retainers including distorted speech, gagging sensation and appliance discomfort. Methods: Sixty-six orthodontic patients (male, 23; female, 43; mean age, $23.42{\pm}10.19$ years) who received orthodontic treatment with fixed orthodontic appliances were randomly assigned to two groups after debonding, a conventional wraparound retainer (CWR) group that fully covers the palate with an acrylic plate and a highly polished surface, and a circumferential comfortable retainer (CCR) group which has a horseshoe shaped base plate with three folds on the anterior region. A questionnaire that had a visual analog scale (VAS) which consists of a 100-mm horizontal line with 2 end-points labeled "no discomfort" on the left and "worst discomfort" on the right, with regard to distorted speech, gagging sensation and discomfort, was administered to patients after 4 weeks of retainer wear. The Mann-Whitney test was used to test the hypothesis that there was no difference between the two retainers. Results: Comparing distorted speech and discomfort, the CCR group significantly had lower values than the CWR group ($p$ < 0.05). Comparing gagging sensation, the CCR group had lower values than the CWR group but there were no statistically significant differences between groups ($p$ = 0.146). Conclusions: In conclusion, the results suggest that the circumferential comfortable retainer (CCR) might facilitate patient compliance and thereby improve the maintenance of the fixed orthodontic treatment outcome.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.3
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• pp.569-575
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• 2005

The aim of this study was to compare the efficiency of sonic and manual toothbrush in decreasing plaque accumulation in young orthodontic patients. Twenty one healthy orthodontic patients attending department of pediatric dentistry at Samsung Medical Center were chosen for the study. The subjects were randomly assigned to either sonic or manual toothbrush and instructed to brush for 2 minutes. Plaque score was assessed with the modified Visible Plaque Index (VPI) before and after brushing. Each brush was repeated twice. A mean plaque reduction of sonic toothbrush was 61.79%(${\pm}7.95$) compared to 69.19%(${\pm}10.08$) of manual toothbrush(p<0.05). With the sonic toothbrush, male presented a mean plaque reduction of 63.07%(${\pm}8.64$) while female presented 60.39%(${\pm}7.30$). For manual toothbrush, male presented 69.33%(${\pm}10.14$) and female presented 69.03%(${\pm}10.55$) reduction of plaque accumulation(p>0.05). There was no statistically significant correlation between age and plaque removal efficacy in this study(p>0.05). Manual toothbrush was significantly more efficient in removing plaque than the sonic toothbrush in young fixed orthodontic patients.