• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전기물성,응용부문
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• pp.257-259
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• 2002

In investigating the characteristics of a neural network, the use of planar microelectrode array shows several advantages over normal intracellular recording[1]. A transparent indium tin oxide(ITO) multi-electrode array(MEA) was fabricated and its top surface was insulated with photodefinable polyimide(HD-8001) except the exposed area for interfacing between the ITO electrodes and the neuronal cells. The exposed ITO electrodes were platinized in order to reduce the impedance between the electrodes and electrolyte. The one-minute platinization with $0.99nA/{\mu}m^2$ current density reduced the average impedance of the electrodes from $2.5M\Omega\;to\;90k\Omega$ at 1kHz in normal ringer solution. Cardiac cells were cultured on this MEA as a pilot study before neuron culture. The signals detected by the platinized electrodes had larger amplitudes and improved signal to noise ratio(SNR) compared to non-platinized electrodes. It is clear that microelectrodes need to have lower impedance to make reliable extracellular recordings, and thus platinization is essential part of MEA fabrication. Burst spike of cultured olfactory bulb was also detected with the MEA having platinized electrodes.

• 한국지하수토양환경학회지:지하수토양환경
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• 제19권3호
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• pp.142-152
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• 2014

In this study, generic characteristics of the acid mine drainage (AMD), removal efficiency of iron, aluminium and manganese by chemical treatment, electrolysis and hybrid process using electrolysis after neutralization were evaluated. The pH of AMD was inversely proportional to the rainfall. In dry-season, the average pH of AMD was ranged from 4.5 to 5.5, showing slight variation. However, the pH of AMD was gradually decreased along with rainfall and dropped to 3.02 in September showing the greatest rainfall. Removal efficiency of heavy metals by chemical treatments using three different neutralizing agents or by electrolysis was low. However, a hybrid process performed with electrolysis after addition of neutralization shows higher removal capacity for heavy metal ions than neutralization-alone and electrolysisalone process.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권2호
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• pp.344-358
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• 2011

Wireless tactical network (WTN) is the most important present-day technology enabling modern network centric warfare. It inherits many features from WMNs, since the WTN is based on existing wireless mesh networks (WMNs). However, it also has distinctive characteristics, such as hierarchical structures and tight QoS (Quality-of-Service) requirements. Little research has been conducted on hierarchical protocols to support various QoS in WMN. We require new protocols specifically optimized for WTNs. Control packets are generally required to find paths and reserve resources for QoS requirements, so data throughput is not degraded due to overhead. The fundamental solution is to adopt topology aggregation, in which a low tier node aggregates and simplifies the topology information and delivers it to a high tier node. The overhead from control packet exchange can be reduced greatly due to decreased information size. Although topology aggregation is effective for low overhead, it also causes the inaccuracy of topology information; thus, incurring low QoS support capability. Therefore, we need a new topology aggregation algorithm to achieve high accuracy. In this paper, we propose a new aggregation algorithm based on star topology. Noting the hierarchical characteristics in military and hierarchical networks, star topology aggregation can be used effectively. Our algorithm uses a limited number of bypasses to increase the exactness of the star topology aggregation. It adjusts topology parameters whenever it adds a bypass. Consequently, the result is highly accurate and has low computational complexity.

• 대한조선학회논문집
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• 제53권6호
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• pp.529-535
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• 2016

This study focuses on the comparison of measured data from 6-DOF motion sensor and strain gauge installed in the IBRV ARAON during 2015 summer voyage in the Arctic. Procedures to calculate the global ice load from MotionPak II inertial measurement system and the local load from stain gauge system are discussed. The ship's speed and peak load are determined in the concept of an ice collision "event". It is found that the peak values in the global ice calculated form whole ship motion analysis fall in the range of 1.5~3 times of the local ice load based in strain gauge measurement.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2019년도 춘계학술대회
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• pp.102-102
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• 2019

This study developed a HPLC analysis method for the determination of avicularin (AL) and quercitrin (QT) in Astilbe chinensis by HPLC. HPLC was performed on a Capcell Pak C18 MGII column ($4.6{\times}250mm$, $5{\mu}m$) with a gradient elution of 0.05% (v/v) trifluoroacetic acid (TFA) and acetonitrile at a flow rate of 1.0 mL/min at $30^{\circ}C$ and a UV detection wavelength of 254 nm. The analytical method was validated for its specificity, precision, accuracy, and linearity. The limits of detection and quantitation were AL 0.09 and 0.28 mg/mL, QT 0.03 and 0.09 mg/mL respectively. Calibration curves showed good linearity (AL r2 > 0.99990 and QT r2 > 0.99994), and the precision of analysis was satisfied (less than AL 0.59%, QT 0.63%). Recoveries of quantified compounds ranged from AL 100.57 to 102.08%, QT 99.94 to 100.64%. These results indicate that the developed HPLC method was applied successfully to the detection of AL and QT in A. chinensis.

• 국제강구조저널
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• 제18권4호
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• pp.1177-1190
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• 2018

This study presents an analytical framework for estimating the thermo-mechanical behavior of a composite beam exposed to fire. The framework involves: a fire simulation from which the evolution of temperature on the structure surface is obtained; data transfer by an interface model, whereby the surface temperature is assigned to the finite element model of the structure for thermo-mechanical analysis; and nonlinear thermo-mechanical analysis for predicting the structural response under high temperatures. We use a plastic-damage model for calculating the response of concrete slabs, and propose a method to determine the stiffness degradation parameter of the plastic-damage model by a nonlinear regression of concrete cylinder test data. To validate simulation results, structural fire experiments have been performed on a real-scale steel-concrete composite beam using the fire load prescribed by ASTM E119 standard fire curve. The calculated evolution of deflection at the center of the beam shows good agreement with experimental results. The local test results as well as the effective plastic strain distribution and section rotation of the composite beam at elevated temperatures are also investigated.

• Nutrition Research and Practice
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• 제15권4호
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• pp.456-467
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• 2021

BACKGROUND/OBJECTIVES: The prevalence of morbid obesity in Korean women has consistently been increasing, while the overall prevalence rate of obesity in Korean women seems to be stable. In addition to bariatric surgery, intragastric balloons (IGBs), as a nonsurgical therapy, have been reported to be effective in weight loss. However, the beneficial effects of IGB in Korean women with obesity have not been fully investigated. The aim of this study was to evaluate the changes in fat mass in Korean women with obesity who had undergone IGB treatment for 6 mon. SUBJECTS/METHODS: Seventy-four women with obesity (body mass index [BMI] ≥ 25.0 kg/m²) were recruited. Clinical data, including general information, comorbidities with obesity, anthropometric data, and changes in the body fat composition before and after IGB treatment, were obtained from the subjects. RESULTS: Most subjects had one or more comorbidities, such as osteoarthropathy and woman's disease, and had poor eating behaviors, including irregular mealtimes, eating quickly, and frequent overeating. Body composition measurements showed that weight, fat mass, and waist-hip circumference ratio decreased significantly at 6 mon after IGB treatment. In particular, women with morbid obesity (BMI ≥ 30 kg/m²) showed 33% excess weight loss. There was no significant difference in skeletal muscle mass and mineral contents after IGB treatment. CONCLUSIONS: This study suggested that 6 mon of IGB treatment can be a beneficial treatment for obesity without muscle mass and bone mineral loss.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2009년도 추계학술발표대회
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• pp.819-820
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• 2009

Standish Group 조사에 의하면 1994년부터 2004년까지 10년간 소프트웨어 프로젝트의 원가 초과율이 180%에서 56%로 낮아졌고 납기 초과율은 164%에서 84%로 낮아져 프로젝트의 품질 수준이 높아진 것으로 조사되었다. 이러한 결과의 교훈은 SW 프로젝트를 보다 작은 시간 프레임으로 나눠 짧은 시간 프레임 내에서 설계, 프로토타이핑, 개발, 테스트를 반복적으로 수행하고 소프트웨어가 자라는 방식의 프로세스 적용이라고 설명했는데 이러한 특징을 갖는 것이 바로 애자일(Agile:기민한) 방법론이다.[1] 그렇다면 애자일 방법 적용이 과연 프로세스 품질 성숙도를 어느 정도 충족시킬 수 있는지에 대한 접근도 이제는 필요하다. 본 연구에서는 웹 서비스 제품 개발 프로세스에 Agile 방법론 중 하나인 Scrum 방법론을 적용한 조직의 사례를 통하여 프로세스 품질 성숙도 요소 충족 여부를 분석함으로써 애자일 방법론을 적용한 조직의 프로세스 품질 성숙도 측정에 도움을 줄 수 있을 것이다.

• 천문학회보
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• 제45권1호
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• pp.40.4-40.4
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• 2020

Kyung Hee university invented the Transformable Reflective Telescope (TRT) for optical experiment and education. The TRT kit can transform into three optical configurations from Newtonian to Cassegrain to Gregorian by exchanging the secondary mirror. We designed the Ebert-Fastie spectrograph as an extension of the TRT kit. The primary mirror of the TRT kit serves as both collimator and camera lens, and the reflective grating as the dispersing element is placed along the optical axis of the primary mirror. We designed and fabricated the grating holder and the source units using 3D printer. Baffle was also fabricated to suppress the stray light, which was reduced by 83%. The spectrograph can observe the optical wavelength range (4000Å~7000Å). Measured resolving power (R=λ/Δλ) was ~700 with slit width of 0.18mm. The spectrograph is optimized for f/24, and the spectral pixel scale is 0.49Å/pixel with Canon 550D detector. We present the sample spectra of discharged Ne, Ar and Kr gases. The flexible setting and high performance make this spectrograph a useful tool for education and experiment.

• 대한화장품학회지
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• 제45권4호
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• pp.333-340
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• 2019

본 연구는 노루오줌(Astilbe chinensis) 추출물을 기능성 화장품소재로 개발하기 위해 avicularin, quercitrin을 지표성분으로 선정하고, 품질관리를 위해 high performance liquid chromatography (HPLC)를 이용하여 분석법을 개발하였다. 분석용 칼럼은 Capcell Pak C₁₈ MGII을, 이동상은 0.05% (v/v) trifluoroacetic acid (TFA)와 아세토니트릴을 사용하여 컬럼 온도는 30℃ 에서 유속 1.0 mL/min 로 검출파장은 254 nm에서 검출하였다. International conference on harmonization (ICH) 가이드라인(version 4, 2005)을 근거로 하여 특이성, 직선성, 정밀성, 정확성, 검출한계 및 정량한계를 분석하여 분석방법을 검증하였다. 분석결과, 검출한계 및 정량한계는 avicularin 0.094 및 0.285 mg/mL, quercitrin 0.031 및 0.095 mg/mL로 나타났으며, 검량곡선은 상관계수 값이 avicularin 0.99990, quercitrin 0.99994로 양호한 직선성을 보였고 정밀성 분석결과도 avicularin 0.59%, quercitrin 0.63% 이하로 확인되었다. 또한, 회수율은 avicularin 100.97 ~ 101.77%, quercitrin 100.18 ~ 100.32% 범위로 정확성이 있음을 알 수 있다. 따라서, 본 분석법은 노루오줌 추출물 지표성분의 분석법으로 적합한 시험법임이 검증되었다.