• 한국농공학회지
• /
• 제20권3호
• /
• pp.4739-4749
• /
• 1978

This studies were conducted to derive synthetic unitgraphs and triangular unitgraphs correlated with watershed characteristics which can be used to the estimation and control of flood for the rational development of Agricultural water resources. Derived Synthetic unitgraphs and Triangular unitgraphs can be applied to the ungaged watersheds were compared with average unitgraphs by observed data. Seven small watersheds were selected as studying basins Han, Geum, Nakdong, Yeongsan and Inchon river system. The results summarized for these studies are as follows: 1. Average unitgraphs by observed data and dimensionless unitgraphs for synthesis were derived for all river systems. 2. Peak discharge per unit area of the unitgraph, qp, was derived as qp=10-0.389-0.0424Lg with a high significance. 3. Formulas for the base width of unitgraph of 50 and 75 percent for peak flow for each water systems was adopted as Table 5. 4. The base length of the unitgraph, Tb, in hours in connection with time to peak, Tp, in hours was expressed as Tb =4.3Tp. 5. Peak discharge, Qp, were obtained as Table 6 by the Triangular form to all subwatersheds. 6. Relative errors in the peak discharge of the synthetic unitgraphs showed to be 7.3 percent to the peak of observed average unitgraphs except errors of peak discharge for Yeongsan river system. This indicates that Synthetic unitgraphs for the small watersheds of Han, Geum, Nakdong and Inchon river systems can be applied to the ungaged watersheds. On the other hand, It was confirmed that the accuracy of Instantaneous Unit Hydrograph with only 1.6 percent as relative errors was approaching more closely to the observed average unitgraph than that of synthetic unitgraph with relative errors. 23.9 percent for Yeongsan river system. 7. Errors in the peak discharge of the triangular unitgraph to the observed average unitgraph showed to be 0.6 percent to 7.5 percent which can be regarded as a high precision within the range of 200 to 500$\textrm{km}^2$ in area. On the contrary, application of triangular unitgraph within the range of 200$\textrm{km}^2$ in area has defined as a unsuitable method because of high relative errors, 26.4 percent to 61.6 percent.

• Geomechanics and Engineering
• /
• 제31권5호
• /
• pp.529-543
• /
• 2022

The lattice-spring-based synthetic rock mass model (LS-SRM) technique has been extensively employed in large open-pit mining and underground projects in the last decade. Since the LS-SRM requires a complex and time-consuming calibration process, a robust approach was developed using the Response Surface Methodology (RSM) to optimize the calibration procedure. For this purpose, numerical models were designed using the Box-Behnken Design technique, and numerical simulations were performed under uniaxial and triaxial stress states. The model input parameters represented the models' micro-mechanical (lattice) properties and the macro-scale properties, including uniaxial compressive strength (UCS), elastic modulus, cohesion, and friction angle constitute the output parameters of the model. The results from RSM models indicate that the lattice UCS and lattice friction angle are the most influential parameters on the macro-scale UCS of the specimen. Moreover, lattice UCS and elastic modulus mainly control macro-scale cohesion. Lattice friction angle (flat joint fiction angle) and lattice elastic modulus affect the macro-scale friction angle. Model validation was performed using physical laboratory experiment results, ranging from weak to hard rock. The results indicated that the RSM model could be employed to calibrate LS-SRM numerical models without a trial-and-error process.

• Advances in nano research
• /
• 제6권1호
• /
• pp.1-19
• /
• 2018

Iron oxide nanoparticles excite researcher interest in biomedical applications due to their low cost, biocompatibility and superparamagnetism properties. Magnetic iron oxide especially magnetite ($Fe_3O_4$) possessed a superparamagnetic behaviour at certain nanosize which beneficial for drug and gene delivery, diagnosis and imaging. The properties of nanoparticles mainly depend on their synthesis procedure. There has been a massive effort in developing the best synthetic strategies to yield appropriate physico-chemical properties namely co-precipitation, thermal decomposition, microemulsions, hydrothermal and sol-gel. In this review, it is discovered that magnetite nanoparticles are best yielded by co-precipitation method owing to their simplicity and large production. However, its magnetic saturation is within range of 70-80 emu/g which is lower than thermal decomposition and hydrothermal methods (80-90 emu/g) at 100 nm. Dimension wise, less than 100 nm is produced by co-precipitation method at $70^{\circ}C-80^{\circ}C$ while thermal decomposition and hydrothermal methods could produce less than 50 nm but at very high temperature ranging between $200^{\circ}C$ and $300^{\circ}C$. Thus, co-precipitation is the optimum method for pre-compliance magnetite nanoparticles preparation (e.g., 100 nm is fit enough for biomedical applications) since thermal decomposition and hydrothermal required more sophisticated facilities.

• 한국방송∙미디어공학회:학술대회논문집
• /
• 한국방송공학회 1999년도 KOBA 방송기술 워크샵 KOBA Broadcasting Technology Workshop
• /
• pp.133-140
• /
• 1999

In this paper, we propose a method of image-based three-dimensional modeling for realistic facial expression. In the proposed method, real human facial images are used to deform a generic three-dimensional mesh model and the deformed model is animated to generate facial expression animation. First, we take several pictures of the same person from several view angles. Then we project a three-dimensional face model onto the plane of each facial image and match the projected model with each image. The results are combined to generate a deformed three-dimensional model. We use the feature-based image metamorphosis to match the projected models with images. We then create a synthetic image from the two-dimensional images of a specific person's face. This synthetic image is texture-mapped to the cylindrical projection of the three-dimensional model. We also propose a muscle-based animation technique to generate realistic facial expression animations. This method facilitates the control of the animation. lastly, we show the animation results of the six represenative facial expressions.

• 식물병연구
• /
• 제12권3호
• /
• pp.260-266
• /
• 2006

Pythium spp. 균에 의해 발생되는 피시움마름병(Pythium blight)은 골프장 퍼팅 그린에서 문제가 되는 대표적 병해이다. 본 연구에서는 Pythium aphanidermatum를 피시움마름병 병원균으로 하여 생물학적 방제법에 이용할 수 있는 길항 미생물을 1차 선발하였고, 선발된 길항 미생물에 대해 폿트 수준의 생물 검정 실험을 실시하였다. 두 실험을 동해 선발된 미생물 중에서 Relative Performance Indies 값을 기준으로 가장 우수한 것을 선별하여 피시움마름병에 대한 길항 미생물로 최종 선발하였고, 동정한 결과 Bacillus subtilis로 밝혀졌다. 최종 선발된 미생물은 B. subtilis GB-0365라 명명하였고, 화학 농약에 대한 내성 실험과 혼용 처리에 따른 효과를 검정하여 화학 농약과 시간의 차이를 두고 교호 살포할 경우 방제효과가 보다 높게 나타났다. 골프장의 간이 묘포장에서 자연 발생된 피시움마름병에 대한 B. subtilis GB-0365의 방제효과를 검증한 결과, 무처리 대비 방제가는 56.4%, 화학 농약 대비 방제가는 60.9%로 우수한 방제 효과을 가진 것으로 판명되었다.

• 한국세라믹학회지
• /
• 제25권5호
• /
• pp.479-487
• /
• 1988

In this study we studied the function of Glycerol as a DCCA(Drying Control Chemical Additives) in the preparation of silica bulk glas through Sol-Gel method. We used TEOS(Tetra Ethyl Ortho Silicate) and maintained the mixing ratio of TEOS : H2O : EtOH : HCI as 1 : 4 : 4 : 0.0007(mol) and varied glycerol input quantity from 0.1vol% considering the ethnaol input quantity as 100vol%. We investigated the changes from Sol-Gel Synthetic solutions to the glass using DT-TG, FT-IR and other instruments. The results obtained from this experiment showed that the dried gels made from the synthetic solutions containing 0.1-1.0vol% of glycerol were easily heat-treated up to 85$0^{\circ}C$ so that transparant bulk silica glass was prepared.

• 한국연소학회:학술대회논문집
• /
• 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
• /
• pp.59-60
• /
• 2012

This paper describes gas turbine combustion characteristics of synthetic gas which is mainly composed of hydrogen and carbon monoxide. The combustion characteristics such as combustion instability, NOx and CO emission, temperatures at turbine inlet, liner and dump plane, and flame structure were investigated when changing when changing $H_2:CO$ ratio, dilution ratio, and $CH_4:syngas$ ratio. From the results, quantitative relationships are derived between key aspects of combustion performance, notably NOx emission. It is concluded that NOx emission of syngas is strongly influenced by the diluent heat capacity and combustion instability. Moreover, NOx control method using diluents such as $N_2$, $CO_2$, steam is verified.

• ETRI Journal
• /
• 제38권2호
• /
• pp.337-346
• /
• 2016

We propose a data-driven kinematic control method for a robotic spatial augmented reality (RSAR) system. We assume a scenario where a robotic device and a projector-camera unit (PCU) are assembled in an ad hoc manner with loose kinematic specifications, which hinders the application of a conventional kinematic control method based on the exact link and joint specifications. In the proposed method, the kinematic relation between a PCU and joints is represented as a set of B-spline surfaces based on sample data rather than analytic or differential equations. The sampling process, which automatically records the values of joint angles and the corresponding external parameters of a PCU, is performed as an off-line process when an RSAR system is installed. In an on-line process, an external parameter of a PCU at a certain joint configuration, which is directly readable from motors, can be computed by evaluating the pre-built B-spline surfaces. We provide details of the proposed method and validate the model through a comparison with an analytic RSAR model with synthetic noises to simulate assembly errors.

• 한국전자파학회논문지
• /
• 제21권9호
• /
• pp.955-964
• /
• 2010

본 논문에서는 기 개발된 능동형 SAR(Synthetic Aperture Radar) 안테나의 송수신 모듈 출력에서 발생하는 이득과 위상 오차를 보정하는 방법에 대해 소개한다. 먼저 오차에 대해 정의하고, 시범 측정을 통해 획득한 측정값을 바탕으로 오차의 특성을 분석한 뒤, 이를 보상하기 위한 송수신 모듈의 제어 방법을 제안하였다. 16조의 송수신 모듈로 구성된 안테나에서 보정 전 이득은 28.2~29.0 dBm, 위상은 $101.7^{\circ}{\sim}165.2^{\circ}$의 분포를 보였으나, 보정후 이득은 27.4~28.0 dBm, 위상은 $116.1^{\circ}{\sim}120.0^{\circ}$의 분포를 나타내었다. 이러한 송수신 모듈의 출력 분포를 바탕으로 배열 이론을 적용하여 안테나 빔 패턴을 생성하고 비교함으로써 제안한 보정 방법이 능동형 SAR 시스템의 성능 만족에 효과적임을 검증하였다.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2003년도 ICCAS
• /
• pp.752-757
• /
• 2003

Recently, 3D structure recovery through self-calibration of camera has been actively researched. Traditional calibration algorithm requires known 3D coordinates of the control points while self-calibration only requires the corresponding points of images, thus it has more flexibility in real application. In general, self-calibration algorithm results in the nonlinear optimization problem using constraints from the intrinsic parameters of the camera. Thus, it requires initial value for the nonlinear minimization. Traditional approaches get the initial values assuming they have the same intrinsic parameters while they are dealing with the situation where the intrinsic parameters of the camera may change. In this paper, we propose new initialization method using the minimum 2 images. Proposed method is based on the assumption that the least violation of the camera’s intrinsic parameter gives more stable initial value. Synthetic and real experiment shows this result.