• 한국전자파학회논문지
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• 제15권9호
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• pp.809-819
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• 2004

본 논문에서는 M/W 중계 주파수의 증설 또는 신규 수용을 가급적 배제하고 필요 회선을 B-WLL 또는 광통신망으로 대체 가능성을 품질 및 경제성 측면에서 분석하였다. 품질 목표에서는 매체간 비교를 위한 전제조건 및 분석방법을 도출하였다. 그리고 E1급을 기준으로 비트오율(BER) $10^{-6}$ 을 만족하도록 기준을 설정하고, 매체별로 가용도에 대한 거리를 산출하였다. 또한 경제성 측면에서는 광통신, M/W, B-WLL 시스템의 기본 구성 단위를 기반으로 서비스 기간, 장비용량, 전송거리, 대용량 전송으로 분류하고 다양한 광전송 회선 및 B-WLL 구성에 대해 분석하였다. 목표 가용도를 99.999 %로 설정시 B-WLL로 M/W를 반경 1.6 km까지 대체 가능하다는 것을 알 수 있었다. 또한 광으로 대체할 경우, 광 관로용의 전주 임대 시에는 서비스 기간에 관계없이 M/W보다 경제성이 있으며, 광 관로 자체를 굴착할 경우에는 고려 방법 중의 어느 경우에 대해서도 경제성이 없는 것으로 판명되었다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.1392-1397
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• 2008

This study is to measure the change of the $CO_2$ and floating dust concentration depending on the volume of the ventilation and the state of on/off the ventilation for the estimation of the air pollution in classroom. The results could be summarized as follows: the test cell was the two full scaled model and the one is set up with ventilation system another was not. the volume of classroom is 170.1m3 and the number of persons are 35. 1)when the ventilation system was not installed, The experimental results of the $CO_2$ concentration showed the average of 2,150ppm and the maximum of 2,740ppm in the classroom. This was the higher than 1,000ppm, the standard value of ASHRAE and the enforcement regulations of School Sanitation Code in Ministry of Education & Human Resources Development, 1000ppm. The $CO_2$ concentration was relatively increasing during school hours. 3)In case of the volume of ventilation of $800m^3$/h, the $CO_2$ concentration of classroom showed the average of 962 ppm and the maximum of 1,380 ppm. This was higher than 1,000ppm, the standard of ASHRAE and the enforcement regulations of School Sanitation Code in Ministry of Education & Human Resources Development. 4)The floating dust(PM10) was the maximum of 0.52 mg/$m^3$, the minimum of 0.25 mg/$m^3$, and the average of 0.32 mg/$m^3$ in case of the ventilation system off. Those were higher than the standard value 0.15 mg/$m^3$. In case of the ventilation system on, the floating dust(PM10) was the maximum of 0.174 mg/$m^3$ , the minimum of 0.048 mg/$m^3$, and the average of 0.078 mg/$m^3$. These were the lower than 0.15 mg/$m^3$, the standard of the enforcement regulations of School Sanitation Code in Ministry of Education & Human Resources Development. 5)The concentrations of $CO_2$ and PM10 were largely depending on the number of students and the ventilation system, The installation of the ventilation system is necessary for the amenity environment and the management of the indoor air quality.

• Journal of Astronomy and Space Sciences
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• 제36권2호
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• pp.75-86
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• 2019

UV Psc is a typical RS CVn type system undergoing dynamic chromosphere activity. We performed photometric observations of the system in 2015 and secured new BVR light curves showing well-defined photometric waves. In this paper, we analyzed the light curves using Wilson-Devinney binary code and investigated the orbital period of the system. The combination of our light curve synthesis with the spectroscopic solution developed by previous investigators yielded the absolute parameters as: $M_1=1.104{\pm}0.042M_{\odot}$, $R_1=1.165{\pm}0.025R_{\odot}$, and $L_1=1.361{\pm} 0.041L_{\odot}$ for the primary star, and $M_2=0.809{\pm}0.082M_{\odot}$, $R_2=0.858{\pm}0.018R_{\odot}$, and $L_2=0.339 {\pm}0.010L_{\odot}$ for the secondary star. The eclipse timing diagram for accurate CCD and photoelectric timings showed that the orbital period may vary either in a downward parabolic manner or a quasi-sinusoidal pattern. If the latter is adopted as a probable pattern for the period change, a more plausible account for the cyclic variation may be the light time effect caused by a circumbinary object rather than an Applegate-mechanism occurring via variable surface magnetic field strengths.

• 한국농공학회지
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• 제41권1호
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• pp.60-71
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• 1999

This study was performed to improve underirable warm greenhouse environment by fog cooling system in summer season. The resultsof droplet size analysis and cooling effects for fog cooling system are summarized as follows ; 1. At the pump pressure of 70kgf/$\textrm{cm}^2$ , the mean (SMD) drop size was 22.6${\mu}{\textrm}{m}$ and the maximum and minimum drop size was 45.68${\mu}{\textrm}{m}$ and 1.73${\mu}{\textrm}{m}$ , respectively, and almost all of the drop size was less than 40${\mu}{\textrm}{m}$. 2. The temperature of fog cooling greenhouse with 60% shading was dropped more than 2$^{\circ}C$ below the ambient temperature , while the greenhouse temperature without shading was 1$^{\circ}C$ higher than the ambient temperature. 3. It was found that fog spraying intervals were significantly influential on cooling effect. 4. When the greenhouse was ventilated sufficiently by natural vent system, green house temperature could be maintained by 2.5$^{\circ}C$ lower than the ambient temperature, while it was difficult to drop the greenhouse temperature below ambient temeperature without sufficient ventilation. 5. It was found that the temperature of experimental greenhouse could be maintained 3$^{\circ}C$ to 14$^{\circ}C$ lower that of control greenhouse though there were variations depending on experimental and weather conditions.

• 한국조명전기설비학회지:조명전기설비
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• 제7권4호
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• pp.42-50
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• 1993

본 연구에서는 자동동조 퍼지 PID 제어 앨고리즘을 사용하여 유도전동기 구동방법을 제안하였다. 퍼지제어에서는 수학적인 모델링이 없이 경험적인 정보를 이용하면 제어가 가능하며 퍼지룩업 테이블을 적절히 이용하면 실시간 제어도 가능한 것이 특징이라 볼 수 있다. 또한, 퍼지규칙을 몇 개의 영역으로 구획하여 시스템의 변화가 발생되고, 또 파라미터의 변화가 유도 전동기 구동 특성에 크게 영향을 주는 것을 감안, 본 시스템의 고성능, 고정도제어를 위하여 퍼지 앨고리즘을 적용하여 파라미터가 자동동조 기능을 갖는 유도전동기의 구동 시스템을 설계, 제작하였으며 그 특성을 기존의 PID 제어방식과 비교하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1845-1850
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• 2011

Permanent Magnet Synchronous Motor(PM motor) of Advanced EMU is the direct drive morot(DDM) without using reduction gear and Interior buried Permanent Magnet Synchronous Motor(IPMSM). Propulsion system for IPMSM control is composed 1C1M. 1C1M is good for each motor control and anti slip/slide. Propulsion control system have completed running test on field and reliability test is in progress.

• Journal of applied mathematics & informatics
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• 제1권1호
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• pp.55-74
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• 1994

We consider an M/G/1 queueing system with multiple priority classes of jobs. Considered preemptive rules are the preemptive-resume preemptive-repeat-identical, and preemptive-repeat-different policies. These three preemptive rules will be analyzed in parallel. The key idea of analysis is based on the consideration of a busy period as composite of delay cycle. As results we present the exact Laplace-Stieltjecs(L.S) transforms of residence time and completion time in the system.

• Current Optics and Photonics
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• 제7권4호
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• pp.354-361
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• 2023

We present the optical design and experimental verification of resolving performance of a 3× long wavelength infrared (LWIR) zoom camera for drones. The effective focal length of the system varies from 24.5 mm at the wide angle position to 75.1 mm at the telephoto position. The design specifications of the system were derived from ground resolved distance (GRD) to recognize 3 m × 6 m target at a distance of 1 km, at the telephoto position. To satisfy the system requirement, the aperture (f-number) of the system is taken as F/1.6 and the final modulation transfer function (MTF) should be higher than 0.1 (10%). The measured MTF in the laboratory was 0.127 (12.7%), exceeds the system requirement. Outdoor targets were used to verify the comprehensive performance of the system. The system resolved 4-bar targets corresponding to the spatial resolution at the distance of 1 km, 1.4 km and 2 km.

• International journal of advanced smart convergence
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• 제11권3호
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• pp.1-6
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• 2022

In this paper, we estimate the mean number of objects in the M/H₂/1 model for web service when the mean object size in the M/H₂/1 model is equal to that of the M/G/1/PS and M/BP/1 models. To this end, we use the mean object size obtained by assuming that the mean latency of deterministic model is equal to that of M/H₂/1, M/G/1/PS, and M/BP/1 models, respectively. Computational experiments show that if the shape parameter of the M/BP/1 model is 1.1 and the system load is greater than 0.35, the mean number of objects in the M/H₂/1 model when mean object size of M/H₂/1 model is the same as that of M/G/1/PS model is almost equal to the mean number of objects in the M/H₂/1 model when the mean object size of M/H₂/1 model is the same as that of M/BP/1 model. In addition, as the upper limit of the M/BP/1 model increases, the number of objects in the M/H₂/1 model converges to one, which increases latency. These results mean that it is efficient to use small-sized objects in the web service environment.

• 한국식품영양과학회지
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• 제39권3호
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• pp.356-362
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• 2010

동결건조된 솔잎(Pinus densiflora needles)으로부터 냉수(PD-CW), 열수(PD-HW)와 메탄올추출물(PD-M)을 분획하여 in vitro에서 Peyer's patch를 경유한 장관면역 활성을 측정한 결과, PD-M 획분에서 유력한 골수세포 증식활성을 나타내었다. 메탄올 추출방법을 확립하기 위하여 MeOH 추출물을 균질화, 교반 또는 환류 등의 방법으로 조제하였을 때, 환류방법으로 조제된 MeOH 추출물에서 유의적(p<0.05)으로 가장 높은 장관면역 활성을 in vitro에서 확인할 수 있었다. 솔잎으로부터 분획된 PD-M을 마우스에 경구 투여하고 Peyer's patch를 분리하여 ex vivo에서의 장관면역 활성도 관찰하였다. 다양한 농도로 1주일 동안 PD-M을 경구투여 한 결과, 1.0 g/kg of BW/day의 용량으로 경구투여 한 C3H/He 마우스의 Peyer's patch로부터 얻은 세포배양 상등액에서 saline 대조군보다 2.5배의 높은 장관면역 활성을 보여주었다(p<0.05). 또한 다양한 농도로 경구투여 된 Peyer's patch 세포의 배양액을 이용하여 측정한 IL-6 생산능은 1.0 g/kg of BW/day의 용량에서 1.13배로 증가하였으나 GM-CSF는 처리 용량에 따라 유의적인 값을 보이지는 않았다. 이러한 결과는 PD-M의 경구투여가 Peyer's patch 세포로부터 GM-CSF와 IL-6 등의 조혈세포 증식인자의 분비를 촉진함을 나타내는 것이며, 이러한 cytokine들이 골수세포 증식의 조절인자로서 작용함을 보여주는 것으로 생각한다.