• 전자공학회논문지C
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• 제34C권6호
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• pp.11-21
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• 1997

The delay models for CMOS invertr presented so far predicted the delay time quite accurately whens input transition-time is very small. But the problem that the accuracy is inclined to decrease becomes apparent as input transition tiem increases. In this paper, a delay model for CMOS inverter is presented, which accuractely predicts the delay time even though input transition-time increases. To inverter must be included in modeling process because the main reason of inaccuracy as input transition tiem is the leakage current through the complementary MOS. For efficient modeling, this paper first models the MOSes with simple I-V charcteristic, with which both the pMOS and the nMOS are considered easily in calculating the inverter delay times. This resulting model needs few parameters and re-models each MOS effectively and simply evaluates output voltage to predict delay time, delay values obtained from this effectively and simply evaluates output voltage to predict delay time, delay values obtained from this model have been found to be within about 5% error rate of the SPICE results. The calculation time to predict the delay time with the model from this paper has the speed of more than 70times as fast as to the SPICE.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2009년 춘계학술대회논문집
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• pp.125-129
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• 2009

In this paper automatic 3D wing shape modeling program is introduced. The program is developed in Visual Basic based on Net Framework 3.5 environment by using CATIA COM Library, and it is used together with CATIA system to model 3D wings with or without flaps. With this program users can easily construct wing models by specifying geometry parameters which are usually design variables with the aid of easy-to-use GUI environment, and specifying sectional airfoil data is done either by using analytic shape functions such as NACA series airfoils or by providing input files with point data describing the airfoil shape. When all the input parameters are provided, users can either work further with the model in the CATIA system which would be automatically started by the program or save the resultant model in the format of users choice. Unstructured grid generation program is also briefly described which can make grid generation task for a 3D wing easy and efficient one when used together with the wing modeling program by choosing STL format as the model's output format.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.173-183
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• 2010

Numerical analysis using a three dimensional finite element program(ABAQUS) is a powerful method which can evaluate the soil-pile-structure interaction under the dynamic loading and reduce the computation time significantly, but has not be widely used because modeling a soil-pile system and setting the parameter for the entire model are difficult and a three dimensional finite element program is not user friendly. However, a three dimensional finite element program is expected to be widely used because of advance in research of modeling technique and development of the modeling and visualization. In this study, ABAQUS is used to simulate the 1g shaking table model pile test, and the numerical results are compared with the 1g shaking table test results. The application about the soil stiffness and boundary condition change is estimated and then parametric study for various input acceleration amplitudes, various input frequencies, and various surcharge is carried out.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2012년도 학술발표회
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• pp.35-35
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• 2012

Most grid-based distributed hydrologic models are complex in terms of data requirements, parameter estimation and computational demand. To address these issues, a simple grid-based hydrologic model is developed in a geographic information system (GIS) environment using storage-release concept. The model is named GIS Storage Release Model (GIS-StoRM). The storage-release concept uses the travel time within each cell to compute howmuch water is stored or released to the watershed outlet at each time step. The travel time within each cell is computed by combining the kinematic wave equation with Manning's equation. The input to GIS-StoRM includes geospatial datasets such as radar rainfall data (NEXRAD), land use and digital elevation model (DEM). The structural framework for GIS-StoRM is developed by exploiting geographic features in GIS as hydrologic modeling objects, which store and process geospatial and temporal information for hydrologic modeling. Hydrologic modeling objects developed in this study handle time series, raster and vector data within GIS to: (i) exchange input-output between modeling objects, (ii) extract parameters from GIS data; and (iii) simulate hydrologic processes. Conceptual and structural framework of GIS StoRM including its application to Pleasant Creek watershed in Indiana will be presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 심포지엄 논문집 정보 및 제어부문
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• pp.54-56
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• 2006

To get the robust and reliable input command, we designed shaping function for target tracking system with commander's handle. Input signals of the commander's handle are generated by human operator. It is response of the human to reduce the error between target and gun. But, tracking error while operator aim a moving target manually gives poor system performance. Input noise, particularly, affects hit accuracy as the system performance. We proposed the design method of input command shaping to reduce the Input noise and to improve the operation ability and convenience. We performed the experiments with combat vehicle, example of Target Tracking System, to show the proposed method is efficient and practical.

• 대한전기학회논문지:전력기술부문A
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• 제48권5호
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• pp.607-614
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• 1999

This paper deals with the design problem of the state estimator for servo system. The servo system has input time delay which depends on the computational time of control algorithm. The delayed input is a factor that brings out the state estimation error. So in order to reduce the state estimation error of the system, we propose a state estimator in which the delayed input of the system is considered. For this purpose, discrete time state space model is established accounting for the delayed input and a state estimator is designed based on this model. Kalman filter algorithm is employed in the design of the state estimator. The proposed estimator is used in the speed control of servo system with delayed input. Performance of the proposed state estimator is exemplified via simulations and experiments for servo system. Also, robustness of the proposed estimator to modeling error by variation of the system parameters is also shown in simulations.

• 한국정밀공학회지
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• 제26권9호
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• pp.88-95
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• 2009

Input shaping has been a very effective control method for reducing payload swing in industrial bridge and gantry cranes. However, conventional input shapers often degrade performance when applied to tower cranes because of the nonlinear coupled dynamics between rotational and radial motions in tower cranes. To alleviate this problem, a new input shaper for tower cranes is developed by means of dynamic modeling, analysis and optimization. This work investigates the tower crane dynamics along with parameters of the tower crane varied. A performance index for input shaper design is proposed so as to reduce the coupled residual vibration of a tower crane using only rotational motion of tower crane. The proposed new input shaper is verified to be effective through simulations and experiments.

• 한국대기환경학회지
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• 제24권3호
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• pp.284-299
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• 2008

Emission input modules was developed to produce emission input data and change some profiles for Sparse Matrix Operator Kernel Emissions (SMOKE) using Clean Air Policy Support System (CAPSS)'s activities and previous studies. Specially, this study was focused to improve chemical speciation and temporal allocation profiles of SMOKE. At first, SCC cord mapping was done. 579 SCC cords of CAPSS were matched with EPA's one. Temporal allocation profiles were changed using CAPSS monthly activities. And Chemical speciation profiles were substituted using Kang et al. (2000) and Lee et al. (2005) studies and Kim et al. (2005) study. Simulation in Seoul Metropolitan Area (Seoul, Incheon, Gyeonggi) using MM5, SMOKE and CMAQ modeling system was done for effect analysis of changed input modules of SMOKE. Emission model results adjusted with new input modules were slightly changed as compared to using EPA's default modules. SMOKE outputs shows that aldehyde emissions were decreased 4.78% after changing chemical profiles, increased 0.85% after implementing new temporal profiles. Toluene emissions were decreased 18.56% by changing chemical speciation profiles, increased 0.67% by replacing temporal profiles as well. Simulated results of air quality were also slightly elevated by using new input modules. Continuous accumulation of domestic data and studies to develop input system for air quality modeling would produce more improved results of air quality prediction.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1052-1055
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• 1996

Piezoelectric actuator is widely used in precision positioning applications due to its excellent positioning resolution. However, serious hysteresis nonlinearity of the actuator deteriorates its precise positioning capability. Evenworse, its hysteresis nonlinearity changes as the actuator input frequency varies. In this study, a simple feedforward scheme is proposed and tested through experiments for precision position control when the variance of the system input frequency is significant.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1998년도 추계학술대회 학술발표 논문집
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• pp.433-439
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• 1998

In this paper, we present an approach to the structure identification based on the input space partition methods and to the parameter identification by hybrid learning method in neuro-fuzzy system. The structure identification can automatically estimate the number of membership function and fuzzy rule using grid partition, tree partition, scatter partition from numerical input-output data. And then the parameter identification is carried out by the hybrid learning scheme using back-propagation and least squares estimate. Finally, we sill show its usefulness for neuro-fuzzy modeling to truck backer-upper control.