• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.164.2-164.2
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• 2012

인공위성레이저추적(SLR, Satellite Laser Ranging) 시스템은 인공위성까지 레이저를 발사하여 되돌아오는 시간간격을 측정함으로서 위성까지의 거리를 측정하는 시스템으로 현존하는 인공위성 궤도결정 시스템으로는 가장 정밀하다. 한국천문연구원은 우주추적 및 감시의 필요성이 증가함에 따라 2008년부터 40cm급 이동형 인공위성레이저추적 시스템을 개발을 시작하였고, 현재 개발을 완료하여 시험운영 중에 있다. 시스템 개발 과정 중에 발생할 수 있는 문제점들을 최소화하기 위해, 설계 단계에서 부품을 포함한 광기계 구조물에 대한 구조해석과, 실험실 프로토타입 구성 등을 실시하였다. 제작된 각 서브시스템별 조립 및 평가는 한국천문연구원이 보유한 광학계 조립 및 평가 시설을 이용하였다. 개발된 이동형 레이저 추적 시스템의 광학부는 추적마운트에 장착되었고, 현장 시험관측을 통해 수신광학계 및 광신호유도계의 정렬 및 제어항목 교정 등을 실시하였으며, 성공적으로 시험 영상 관측을 완료하였다. 이 발표에서는 이동형 레이저 추적 시스템 광학계의 개발 과정과 그 결과에 대해 보고한다.

• Journal of Environmental Health Sciences
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• v.32 no.5 s.92
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• pp.440-445
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• 2006

Acetaminophen (paracetamol), generally used as a pain reducing agent, has good analgesic efficacy in toothaches and headaches, but is of little use in inflammatory and visceral pain. This study was performed to analyze the level of acetaminophen in the Kyongahn river and to investigate the ecological risks of target compounds. Sampling sites were Haesil, Soopyo, Wangsan, Kyongahn, Jiwol, Kwangdong, Paldang and they were analyzed in June and August, 2005. Acute toxicity of acetaminophen wwas evaluated for Daphnia magna. From the ecotoxicological results, environmental risk assessments were performed for acetaminophen residues in Kyongahn river to predict their potential adverse effect. Acetaminophen was detected at Kyonahn river, $0.439{\mu}g/l$). The toxic concentration of acetaminophen calculated with 48-h $LC_{50}$ values as 16.9 mg/l. These results indicated that acetaminophen had no significant ecotoxicological impact on short-term acute exposure.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.11
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• pp.45-52
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• 2005

In this paper, we propose the PLL system of the local oscillator system for the millimeter wave band's radio astronomy receiving system. The development of the proposed local oscillator system based on the YIG oscillator VCO with $26.5\~40GHz$ specification. This system consists of the oscillator part including the YIG VCO, the harmonic mixer, and the isolator, the RF processing part including the triplexer, limiter, and RF discrimination processor, and the PLL system including YIG modulator and controller. Based on this configuration, we verify the frequency and power stability of the developed local oscillator system according to some temperature variation. From this test results we confirm the stable output frequency and power characteristic peformance of the developed LO system at constant temperature.

• Journal of Wetlands Research
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• v.11 no.1
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• pp.29-37
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• 2009

This study was conducted on the marsh of Paldang dam and Gyungan-cheon, Gyeonggi-do province. 6 species bred on the emergent plants and the nests of Common Coots Fulica atra, Common Moorhens Gallinula chloropus, Great Reed-Warblers Acrocephalus orientalis, Yellow Bitterns Ixobrychus eurhythmus, Little Grebes Podiceps ruficollis and Great Crested Grebes Podiceps cristatus were found. The main vegetations of the nests were Narrow Leaf Cattails Typha angustata, Reeds Phragmites communis, and Wild Rices Zizania latitolia. Particularly, Narrow Leaf Cattails were the most favorite plants for breeding birds. Few nests were found on the emergent plants covered with rubbish, or on high density. And no nests found on the inside shrubs. The mean density of nests on the marsh was 3.1 nests per ha and the nests were highest in Non-island as 17 nests per ha. The nest density on the area of Sonae-islands was higher than the area of Kyangdong-kyo bridge. This would be related on the bulk of narrow-leaf cattails and the quality of water.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.1
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• pp.89-102
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• 2010

Future uncertainty on water demand caused by future climate condition and water consumption leads a difficulty to determine the reservoir operation rule for supplying sufficient water to users. It is, thus, important to operate reservoirs not only for distributing enough water to users using the limited water resources but also for preventing floods and drought under the unknown future condition. In this study, the reservoir storage is determined in the first stage when future condition is unknown, and then, water distribution to users and river stream is optimized using the available water resources from the first stage decision using 2-stage stochastic linear programming (2-SLP). The objective function is to minimize the difference between target and actual water storage in reservoirs and the water shortage in users and river stream. Hedging rule defined by a precaution against severe drought by restricting outflow when reservoir storage decreases below a target, is also applied in the reservoir operation rule for improving the model applicability to the real system. The developed model is applied in a system with five reservoirs in the Han River basin, Korea to optimize the multi-reservoir system under various future water demand scenarios. Three multi-purposed dams - Chungju, Hoengseong, and Soyanggang - are considered in the model. Gwangdong and Hwacheon dams are also considered in the system due to the large capacity of the reservoirs, but they are primarily for water supply and power generation, respectively. As a result, the water demand of users and river stream are satisfied in most cases. The reservoirs are operated successfully to store enough water during the wet season for preparing the coming drought and also for reducing downstream flood risk. The developed model can provide an effective guideline of multi-reservoir operation rules in the basin.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.11 s.353
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• pp.210-215
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• 2006

In this paper, we develop the PLL system of the local oscillator system using Gunn oscillator VCO for millimeter wave band receiving system. The local oscillator system consists of the $86{\sim}115GHz$ Gunn. diode oscillator part, the RF processing part including the diplexer and the harmonic mixer, and the DPLL system including Gunn modulator and controller. Based on this configuration, we verify the frequency and power stability of the developed local oscillator system. We developed system which applied to DPLL technique instead of the existing analog PLL method to accomplish this purpose. The developed system for this purpose is tested the frequency and power stability for a long time to confirm performance. Since we confirmed this system that had frequency characteristic of within ${\pm}10Hz$, very fine output drift power characteristic of $0.2{\sim}0.3dBm$ and about 200MHz locking range, it verified suitable for cosmic radio receiving system through the test result.

• Korean Journal of Environmental Agriculture
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• v.1 no.2
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• pp.116-122
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• 1982

Investigation on the water quality of Hwangguji River and experiment on the effects of nitrogen and soil improvements were carried out in the paddy field irrigated with polluted water of the river. The obtained results are as follows: 1) Amount of COD and $NH_4-N$ in water of the river were 54 ppm, 65 ppm, during the seeding time, and were 52 ppm, 512 ppm during the transplanting time respectively. Their concentrations were over the standard levels. It seemed that the water pollution was mainly caused by organic waste matters. 2) It seemed that the effective nitrogen level was $7{\sim}8$kg/10a in the paddy field irrigated with polluted water of the river. 3) The rice yields of potassium twice quantity application plot with N.P.K. fertilizer, the calcium application plot with N.P.K. fertilizer and the combined plot with potassium, wallarstonite, calcium and fresh straw, were increased 4, 5 and 8%, respectively, than that of the N.P.K. fertilizer standard level plot.

• The Journal of the Acoustical Society of Korea
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• v.22 no.8
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• pp.727-739
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• 2003

In this paper, we propose a generation method of regression classes for adaptation in the HM-Net (Hidden Markov Network) system. The MLLR (Maximum Likelihood Linear Regression) adaptation approach is applied to the HM-Net speech recognition system for expressing the characteristics of speaker effectively and the use of HM-Net in various tasks. For the state level sharing, the context domain state splitting of PDT-SSS (Phonetic Decision Tree-based Successive State Splitting) algorithm, which has the contextual and time domain clustering, is adopted. In each state of contextual domain, the desired phoneme classes are determined by splitting the context information (classes) including target speaker's speech data. The number of adaptation parameters, such as means and variances, is autonomously controlled by contextual domain state splitting of PDT-SSS, depending on the context information and the amount of adaptation utterances from a new speaker. The experiments are performed to verify the effectiveness of the proposed method on the KLE (The center for Korean Language Engineering) 452 data and YNU (Yeungnam Dniv) 200 data. The experimental results show that the accuracies of phone, word, and sentence recognition system increased by 34∼37%, 9%, and 20%, respectively, Compared with performance according to the length of adaptation utterances, the performance are also significantly improved even in short adaptation utterances. Therefore, we can argue that the proposed regression class method is well applied to HM-Net speech recognition system employing MLLR speaker adaptation.

• Journal of Life Science
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• v.25 no.1
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• pp.93-100
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• 2015

Pachymic acid (PA) is a lanostane-type triterpenoid derived from the Poria cocos mushroom. Several beneficial biological features of PA provide medicine with a wide variety of valuable effects, such as anticancer and anti-inflammatory activity; it also has antioxidant effects against oxidative stress. Nonetheless, the biological properties and mechanisms that produce this anti-cancer action of PA remain largely undetermined. In this study, we investigated the pro-apoptotic effects of PA in T24 human bladder cancer cells. It was found that PA could inhibit the cell growth of T24 cells in a dose-dependent manner, which was associated with the induction of apoptotic cell death, as evidenced by the formation of apoptotic bodies and chromatin condensation and accumulation of cells in the sub-G1 phase. The induction of apoptotic cell death by PA was connected with an up-regulation of pro-apoptotic Bax and Bad protein expression and down-regulation of anti-apoptotic Bcl-2 and Bcl-xL proteins, and inhibition of apoptosis family proteins. In addition, apoptosis-inducing concentrations of PA induced the activation of caspase-9, an initiator caspase of the mitochondrial-mediated intrinsic pathway, and caspase-3, accompanied by proteolytic degradation of poly (ADP-ribose)-polymerase. PA also induced apoptosis via a death receptor-mediated extrinsic pathway by caspase-8 activation, resulting in the truncation of Bid and suggesting the existence of cross-talk between the extrinsic and intrinsic pathways. Taken together, the present results suggest that PA may be a potential chemotherapeutic agent for the control of human bladder cancer cells.

• Journal of the Institute of Convergence Signal Processing
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• v.9 no.1
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• pp.62-74
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• 2008

In this paper, we would like to propose the design of symmetric digital filter core in order to use in the radio astronomy. The function of FIR filter core would be designed by VHDL code required at the Data Acquisition System (DAS) of Korean VLBI Network (KVN) based on the FPGA chip of Vertex-4 SX55 model of Xilinx company. The designed digital filter has the symmetric structure to increase the effectiveness of system by sharing the digital filter coefficient. The SFFU(Symmetric FIR Filter Unit) use the parallel processing method to perform the data processing efficiently by using the constrained system clock. In this paper, therefore, for the effective design of SFFU, the Unified Synthesis software ISE Foundation and Core Generator which has excellent GUI environment were used to overall IP core synthesis and experiments. Through the synthesis results of digital filter core, we verified the resource usage is less than 40% such as Slice LUT and achieved the maximum operation frequency is more than 260MHz. We also confirmed the SFFU would be well operated without error according to the SFFU simulation result using the Modelsim 6.1a of Mentor Graphics Company. To verify the function of SFFU, we carried out the additional simulation experiments using the pseudo signal to the Matlab software. From the comparison experimental results of simulation and the designed digital FIR filter, we confirmed the FIR filter was well performed with filter's basic function. So we verified the effectiveness of the designed FIR digital filter with symmetric structure using FPGA and VHDL.