• Proceedings of the KIPE Conference
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• 2016.11a
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• pp.171-173
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• 2016

일반적으로 대형 버스 및 트럭 등 같은 경우, 부하가 아주 크다. 또한 내리막길이나 장거리 운행 시에 잦은 제동으로 인하여 마찰을 이용한 기존 방식의 브레이크들은 브레이크 파열 및 페이드 현상 때문에 제동 안전성에 문제가 있다. 이러한 제동 부담을 분담하기 위해 현재 보조브레이크(리타더)가 필수적이며, 엔진 계통의 보조브레이크가 아닌 비접촉식 브레이크 같은 친환경 보조브레이크가 요구되고 있다. 그리고 차량 제동시 발생하는 기계에너지를 전기에너지로 회생하여 에너지효율을 향상시키려는 연구가 현재 활발히 진행되고 있다. 본 논문에서는 와전류를 이용한 전자기형 리타더에서 발생되는 전기에너지를 회수하기 위한 전압 제어 방법을 다룰 것이다. 리타더의 제동에너지를 전기에너지로 회생하기 위해 L-C 공진회로로 구성하였다. 리타더를 자여자 유도발전기(Self-Excited Induction Generator)로 모델링 하였고 이를 토대로 시뮬레이션 및 실험을 진행하였다. 자여자 유도발전기의 구동 조건에 대해서 언급하고 이를 파라미터에 따라 3-D map으로 만들었다. 또 회로 중의 FET 게이트에 전압을 인가하는 제어장치의 구동펄스에 따라 바뀌는 공진회로의 전압을 분석하였으며, 이 전압을 제어하기 위하여 PI 제어기를 이용한 알고리즘을 제안하였다. 이 전압을 3상 AC/DC컨버터를 통과한 후 DC/DC컨버터를 통하여 차량 내부의 배터리에 충전되는데 제어를 위해 3상 AC/DC에서의 전압 리플을 MA(Moving Average) 방식의 필터를 사용하여 DC/DC컨버터의 입력에 맞도록 제어하였다. 이와 같이 전자기형 리타더에서 유도되는 전압을 제어기의 제어 펄스에 따라 제어할 수 있으며 Matlab Simulink를 이용하여 리타더의 모델과 그 제어기의 타당성을 보였다. 또 실제 M-G Set 실험을 통하여 그 연관성을 확인하였다.

• Journal of Broadcast Engineering
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• v.10 no.4 s.29
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• pp.632-642
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• 2005

This paper presents a new vertex selection scheme for the polygon-based contour approximation. In the proposed method, the entire contour is partitioned into partial segments and they are approximated adaptively with variable accuracy. The approximation accuracy of each segment is controlled based on its relative significance. By computing the relative significance with the texture degradation in the approximation error region, the visual quality enhancement in the reconstructed frames can be achieved under the same amount of the contour data. For this purpose, a decision rule for $d_{max}$ is derived based on inter-region contrasts. In addition, an adaptive vertex selection method using the derived rule is proposed. Experimental results are presented to show the superiority of the proposed method over conventional methods.

• The Journal of the Korea Contents Association
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• v.7 no.1
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• pp.124-130
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• 2007

A rectangular coaxial line is mainly utilized as a transition structure from a coaxial line to a rectangular waveguide. A TEM cell is also widely used to measure the EMC characteristics of a DUT. In order to understand the operations of a rectangular coaxial line and a TEM cell, it is essential to analyze the dispersion relations of a rectangular coaxial line and a TEM cell. In this paper, we present simple yet accurate dispersion relations of the TE and TM higher modes based on the TEM mode. Manipulating a mode-matching technique and a Green's function approach allows us to obtain the analytic dispersion equations of a rectangular coaxial line and a TEM cell. In our approach, a rectangular coaxial line is divided into four L-blocks and its electromagnetic fields representations are easily obtained with a superposition. To verify the convergence of our dispersion relations, we perform numerical computations and compare our results with those of FDTD.

• Journal of Life Science
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• v.28 no.12
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• pp.1507-1515
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• 2018

Benign prostatic hyperplasia (BPH) is characterized by prostatic hypertrophy mainly in the elderly. Corni Fructus is reportedly effective in the prevention and treatment of various diseases, but its efficacy on BPH has not been previously studied. In the present study, we investigated whether or not a Corni Fructus water extract (CF) could prevent testosterone-induced prostatic hyperplasia in rats. To induce BPH, castrated rats were subcutaneously injected with testosterone propionate (TP). CF was administered daily by oral gavage, along with the TP injections, and finasteride, a selective inhibitor of $5{\alpha}$-reductase type 2, was used as a positive control. The results show that CF significantly reduces prostate weight and histopathologic changes while also decreasing levels of serum dihydrotestosterone, similar to the finasteride-treated group. CF also suppresses TP-induced $5{\alpha}$-reductase expression and concentration in prostate tissue and serum, respectively. Furthermore, CF markedly inhibited TP-induced expression of the androgen receptor (AR) and the steroid receptor coactivator 1, an AR coactivator, which was associated with a decrease in prostate-specific antigen levels in both serum and prostate tissue. In conclusion, the results of this study indicate that CF weakens BPH status by inactivation of $5{\alpha}$-reductase and AR.

• Korean Journal of Food Science and Technology
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• v.47 no.3
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• pp.388-393
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• 2015

This study aimed to investigate the therapeutic effect of rutin against whole-body ${\gamma}$-irradiation in BALB/c mice. BALB/c mice were randomly divided into four groups and exposed to 6 Gy ${\gamma}$-irradiation. One hour later, mice were orally administered rutin (50 and 100 mg/kg) for seven consecutive days. ${\gamma}$-Irradiation (6 Gy) resulted in cellular damage as manifested by elevated levels of plasma hepatic marker enzymes and lipid peroxidation in liver tissue, accompanied with decreased spleen and thymus indices, and white blood cell count. In addition, ${\gamma}$-irradiation significantly decreased the levels of antioxidant enzymes such as superoxide dismutase, glutathione peroxidase and catalase. Rutin treatment significantly protected against ${\gamma}$-irradiation-induced cellular damage, which was evident by the improvement in the status of most of the investigated parameters. Therefore, rutin has beneficial effects against radiation-induced damage.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.12
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• pp.1889-1895
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• 2014

Radiation-induced hydrocarbon contents of dried anchovy, jiri anchovy, and large-eyed herring were evaluated following electron-beam irradiation at doses of 1, 3, 5, 7, and 10 kGy. GC/MS identification of the induced hydrocarbons by irradiation was conducted after lipid separation by soxtec, followed by florosil column chromatography. 1-Tetradecene ($C_{14:1}$) and pentadecane ($C_{15:0}$) derived from palmitic acid, 1-hexadecene ($C_{16:1}$) and heptadecane ($C_{17:0}$) from stearic acid, and 8-heptadecene ($C_{17:1}$) and 1,7-hexadecadiene ($C_{16:2}$) from oleic acid were the major induced hydrocarbons in irradiated dried anchovy, jiri anchovy, and large-eyed herring samples. At the same irradiation dose, concentration of induced hydrocarbons differed from fatty acid composition and increased in accordance with radiation dose level. Radiation-induced hydrocarbons, such as 1-tetradecene ($C_{14:1}$), 1-hexadecene ($C_{16:2}$), 8-heptadecene ($C_{17:1}$), and 1,7-hexadecadiene ($C_{16:2}$), were confirmed as irradiation marker compounds. Therefore, these marker compounds could be used to distinguish electron-beam irradiated dried anchovy, jiri anchovy, and large-eyed herring from non-irradiated ones.

• Journal of Korean Society for Geospatial Information Science
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• v.21 no.4
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• pp.3-12
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• 2013

In order to evaluate dredging results scientifically the system which can manage and estimate working process by monitoring dredging process in real-time needs to be constructed. We constructed real-time dredging management system for guidance of a dredging vessel and for survey of dredging construction. This system was designed to have functions of dredger location by GPS, ship direction measurement by GPS/Gyroscope combination, Grab position measurement, dredging depth measurement and correction. In addition, we developed the programs for controlling and operating the constructed system. The system could induce the vessel to accurate position and conduct dredging according to plan and the effectiveness of the system was evaluated through the results of application to actual dredging construction site.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.1
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• pp.1-7
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• 2007

This study introduces an elastic parabolic cable element for initial shaping analysis of cable-stayed bridges. First, an elastic catenary cable theory is shortly summarized by deriving the compatibility condition and the tangent stiffness matrices of the elastic catenary cable element. Next, the force-deformation relations and the tangent stiffness matrices of the elastic parabolic cable elements are derived from the assumption that sag configuration under self-weights is small. In addition the equivalent cable tension is defined in the chord-wise direction. Finally, to confirm the accuracy of this element, initial shaping analysis of cable-stayed bridges under dead loads is executed using TCUD in which stay cables are modeled by an elastic parabolic cable and an elastic catenary cable element, respectively. Resultantly it turns that unstrained lengths of stay cables, the equivalent cable tensions, and maximum tensions by the parabolic cable element are nearly the same as those by the catenary cable elements.

• Journal of Acupuncture Research
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• v.27 no.3
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• pp.1-13
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• 2010

목적 : 이 연구는 봉약침의 봉독과 그 주요성분인 멜리틴이 NF-${\kappa}B$의 활성억제와 세포자멸사 관련 단백질의 발현 조절을 통하여 세포자멸사를 유도함으로써 전립선 암세포주인 PC-3 세포의 성장을 억제하는지를 확인하고 해당 기전을 살펴보고자 하였다. 방법 : 봉독이나 멜리틴을 처리한 후 PC-3의 성장억제를 관찰하기 위해 WST-1 assay, CCK-8 assay를 시행하였고, 세포자멸사 조절단백질의 변동 관찰에는 western blot analysis를 시행하였고, 세포자멸사와 연관된 NF-${\kappa}B$의 활성 변화를 관찰하기 위해 EMSA를 시행하였으며, PC-3에서 봉독이나 멜리틴과 NF-${\kappa}B$의 상호작용을 관찰하기 위해 transient transfection assay를 시행하여 세포생존율과 NF-${\kappa}B$의 활성 변동을 측정하였다. 결과 : PC-3 세포에 봉독이나 멜리틴을 처리한 후, 전립선암세포의 성장, 세포자멸사의 유발, 세포자멸사 관련 단백질의 발현, NF-${\kappa}B$의 활성, NF-${\kappa}B$의 p50, $IKK{\alpha}$, $IKK{\beta}$ 치환 후 NF-${\kappa}B$의 활성과 PC-3 세포 증식에 미치는 영향을 관찰하여 다음과 같은 결과를 얻었다. 1. PC-3 세포에서 봉독이나 멜리틴을 처리한 후 세포자멸사가 유도되어 세포성장이 억제되었고, 세포자멸사 관련 단백질 중 분리된 PARP, caspase-3, -9는 유의한 증가를, Bcl-2, XIAP, cXIAP2는 유의한 감소를 나타내었다. 2. PC-3 세포에서 봉독이나 멜리틴을 처리한 후 NF-${\kappa}B$의 활성은 유의한 감소를 나타내었다. 3. PC-3 세포에서 NF-${\kappa}B$의 p50, $IKK{\alpha}$, $IKK{\beta}$를 치환하여 작용기를 없애고 봉독이나 멜리틴을 처리하였을 경우에도 NF-${\kappa}B$의 활성이 유의한 감소를 나타내었다. 결론 : 이상의 결과는 봉독이나 멜리틴이 NF-${\kappa}B$의 활성 억제를 통하여 인간 전립선암세포주인 PC-3의 세포자멸사를 유발함으로써 증식억제 효과가 있음을 입증한 것으로, 전립선암의 예방과 치료에 대한 효과적인 치료제 개발에 도움이 될 것으로 기대된다.

• Journal of Advanced Navigation Technology
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• v.21 no.1
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• pp.84-89
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• 2017

This paper presents a dual-wideband bandpass filter (BPF) with high band-to-band isolation and skirt selectivity using distributed composite right/left-handed (CRLH) transmission line (TL) quad-mode resonators (QMRs). The results of the proposed distributed CRLH TL unit cell analysis are used to establish the scattering parameters and the resonance frequencies of the QMR constituting the dual-wideband BPF. A novel dual-wideband bandpass filter is designed and fabricated, using the derived scattering characteristics. The measured results show that the fabricated dual-wideband bandpass filter has an insertion loss of less than 1.08dB in the lower band, and of 2.01dB in the upper band, a bandwidth of 2.8-5.52GHz and 9.68-12.26GHz, and a band-to-band isolation of more than 38dB, from 6.34-8.42GHz.