• Journal of the Korean Society for Railway
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• v.16 no.3
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• pp.226-232
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• 2013

Recently, CO2 reduction policies are being promoted as parts of ESSD(Environmentally Sound and Sustainable Development), and many local governments are interested in monorails as a new means of transport. Here we report on a feasibility study for introducing a monorail system by considering the travel demands in the Mt. Bomun area in Daejeon, based on the area's population. The feasibility of a monorail system on Mt.Bomun varies with respect to the demographic scale, mode shares, and operational distances. The strategies introduced here will help identify any tourist spots where local governments are trying to introduce monorail systems as a new system of transit.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.574-577
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• 2010

이번 연구에서는 저속 비압축성 유체-구조 연성을 고려한 위상 최적화을 위해 새로운 모노리틱 해석을 개발한다. 이 새로운 해석 기법에서는 기존의 유체-구조 연성 시스템 해석 기법에서 유체와 구조 영역을 분리하고 연성 조건을 만족시키는 것과 다르게 하나의 일치된 해석 방정식을 유체 영역과 구조 영역에 동일하게 적용한다. 또한, 경계조건을 만족시키기 위하여 단일화 된 해석 방정식의 물성치를 바꾸어주는 새로운 방식을 제시하였다. 이 새로운 방법에서는 유체, 구조 영역을 분리하지 않고 Navier-Stoke's 방정식과 선형 탄성식을 동시에 사용하였다. 또한, 유체-구조 영역이 연성 해석 중 변화하는 것을 반영하기 위하여 구조 변위를 이용하여 Deformation tensor를 계산하였고 이를 이용하여 변형 후에서의 Navier-Stoke 방정식의 미분을 계산하는 방법을 제안하였다. 그리고, 정상 상태 유체를 가정하고 속도에 비례하는 마찰힘인 Darcy's force 항을 Navier-Stoke 방정식에 넣고 이 마찰 힘의 크기를 변화시킴으로 해서 유체 방정식에서의 연성 경계 조건을 만족시켰다. 선형 탄성 방정식에서 Divergence이론을 이용해서 경계에서 작용하는 외력이 하는 일을 내부 시스템에 하는 일로 계산하였다. 개발된 모노리스 해석 방법을 이용하여 저속 비압축성 유체가 구조에 미치는 압축력을 계산하였고 이용하여 컴플라이언트 미케니즘을 설계하였다.

• Transactions of the KSME C: Technology and Education
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• v.3 no.2
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• pp.131-140
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• 2015

The mono-ski for the paraplegia designed to skiing is formed as seat bucket on the sled. The impact force transferred by snow surface during skiing is absorbed by the leg joints of normal human, but it is transferred to the human body on the seat when using mono-ski. Most of commercially available mono-ski have absorbing device and link mechanism between seat and ski mount in order to complement it. In this study we developed the comfort evaluation model that could provide skiing simulation of mono-ski with hydraulic damper and analyzed vibrational acceleration occurred during skiing uneven surface. The evaluation method used in this study is the international standard BS6841. We evaluated comfort performance of mono-ski in accordance with nozzle adjustment of hydraulic damper.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.11
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• pp.1299-1308
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• 2007

In this paper, we propose the calibration method of monopulse slope to minimize the variation of angle estimate in frequency agile noncoherent monopulse system. We analyze the monopulse slope characteristics of antenna and RF receiver including the phase and gain imbalances of each receiving channel and present the calibration method to minimize the phase and gain imbalances of RF receiver channels including antenna. In addition, we present the calibration method using channel switching to minimize the gain imbalance of IF receiver channels. The measured average monopulse slope within the frequency bandwidth is -0.96, the maximum variation of angle estimate is similar to theoretical value, $0.15^{\circ}$ at ${\pm}2^{\circ}$ azimuth and $0.03^{\circ}$ at $0^{\circ}$ azimuth.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.1
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• pp.26-33
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• 2006

This study investigated the characteristics of the biofilm removal by free chlorine or monochloramine. The simulated drinking water distribution pipes on which biofilms had been formed were supplied with tap water containing 0.5, 1.0, 2.0 mg/L of free chlorine or monochloramine residuals. The biofilm removal was characterized by measurement of attached HPC and biomass on pipe surfaces. Chlorine was more effective in both inactivation of attached viable heterotrophic bacteria and removal of biofilm biomass compared to monochloramine. Biofilm matrix was not much eliminated from the surfaces by monochloramine disinfection. Free chlorine residual of 2.0 mg/L was found to be effective in biomass removal. However, biofilm level as low as $10CFU/cm^2$ of attached HPC and $5{\mu}g/cm^2$ of biomass still remained on the surfaces at 2.0 mg/L of chlorine residual. The measurement of biomass appeared to be a useful means in evaluating the characteristics of biofilm removal.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.2
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• pp.192-196
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• 2007

In this study, a formation of N-nitrosodimethylamine(NDMA), a disinfection by-product, was investigated as a result of monochloramine addition in water. The NDMA formation was studied in terms of pH, dimethylamine(DMA), monochloramine concentration, and nitrogen composition in monochloramine. At a fixed DMA concentration of 0.01 mM or 0.05 mM, the NDMA formed concentration was quite different when the monochloramine to DMA ratio is less or greater than 1. The NDMA formation increased with increasing pH and a ratio of nitrogen composition in monochloramine to total nitrogen composition. At pH 7 and 8, more than five times higher NDMA formation was produced as a result of five times increase in DMA concentration. It was likely that monochloramine could be related to stimulate NDMA formation, if monochloramine may be produced with chlorine disinfection, in water treatment systems.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.5
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• pp.514-520
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• 2015

Sidelobe canceller(SLC) requires main beam pattern(SUM beam) and auxiliary beam patterns for rejection of sidelobe noise jammer. For best performance of sidelobe noise jamming cancellation of adaptive SLC, gain dominant region of each auxiliary beam pattern shall not be overlapped one another in elevation/azimuth regions of sidelobe of main beam, and beam patterns of auxiliary channels should have low gains in regions of mainlobe of main beam. In the monopulse radar, the difference beam patterns for monopulse processing have these properties. This paper proposes the method using data from the difference channel for monopulse processing as data from auxiliary channel for sidelobe cancellation. For the proposed SLC, the results of simulation and performance analysis was presented. If the proposed method is used in the monopulse radar, SLC can be constructed by using basic SUM and difference channels without extra channel composition.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.1
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• pp.229-236
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• 2017

In general, an error budget of monopulse radar is proposed by manufacturer who assuming that all of external enviromental error resources such as multipath, glint, dynamic lag variation are removed. So until now, a measurement uncertainty of monopulse radar can be discussed including external enviromental error resources. In this paper, it is described that which kinds of error resource can effect on monopulse radar measurement uncertainty for different target property. To prove it experimentally, at first a simulation result is described assuming that all of external enviromental error resources are removed. It only includes receiver thermal noise. And then, monopulse radar measurement uncertainty estimation results tracking on calibration target which is fixed on specific position, calibration sphere which is moving slowly, weapon systems firing test which is moving fast are described quantitativly. All of these targets have different dynamic property.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.1
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• pp.53-64
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• 2004

This paper proposes a monopulse beamforming network to estimate a target angle in interference conditions. The proposed system estimates the target direction of arrival (DOA) with two separate beamformings for azimuth and elevation with a planar may. The elevation is extracted from adaptive beamforming in the azimuth direction and the azimuth from adaptive beamforming in the elevation direction. Unlike conventional monopulse beamforming techniques using complex correction formulas or a cascaded architecture of an adaptive array and a mainlobe canceller, the proposed system is very efficient from the computational complexity. The advantage is from fact that the monopulse ratio of the proposed system does not depend on the adapted weights. Moreover, the proposed system can estimate the DOA of the target even for multiple mainlobe interferences since it does not need my kinds of mainlobe maintenance technique.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.12 s.91
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• pp.1190-1198
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• 2004

In this paper, meander-line planar monopole antenna mounted on PCS/IMT-2000/WLAN handset for SAR reduction is designed. Frequency characteristics and SAR value optimized with various design parameters are analyzed and designed. Designed internal monopole antenna mounted on the handset is simulated. The 1 g and 10 g peak average SARs of internal monopole antenna are 0.656 and 0.387 W/kg respectively. And internal monopole antenna and external monopole antenna attached on the handset are tested. As a result, internal monopole antenna 1 g and 10 g peak average SARs are 0.686 and 0.356 W/kg. And external monopole antenna's results are 1.33 and 0.812 W/kg, respectively. So internal monopole antenna has a about $50\%$ SAR reduction in comparison with external monopole antenna.