• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.101.5-101
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• 2002

A vehicle simulator is made here to simulate the lateral control of vehicles. Dead-reckoning sensors which consist of gyroscopes and accelerometers are utilized for the positioning of it. A significant side-slip occurs when the developed vehicle is drove autonomously. To cope with the side-slip, the vehicle is steered to follow the reference yaw rate which is generated by the relationship between the target point and the position of vehicle. The experimental results show the good performances of lane tracking and the passenger comfort.

• Korean Journal of Chemical Engineering
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• 제36권3호
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• pp.356-367
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• 2019

This work presents an advanced and systematic approach to analytically design the optimal parameters of a two parameter second-order internal model control (IMC) filter that satisfies operational constraints on the output process, the manipulated variable as well as rate of change of the manipulated variable, for a first-order plus dead time (FOPDT) process. The IMC parameters are designed to minimize a control objective function composed of the weighted sum of the error between the process variable and the set point, and the rate of change of the manipulated variable, and to satisfy the desired constraints. The feasible region of the constrained IMC control parameters was graphically analyzed, as the process parameters and the constraints varied. The resulting constrained IMC control parameters were also used to find the corresponding industrial proportional-integral controller parameters of a Smith predictor structure.

• Journal of Climate Change Research
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• 제6권1호
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• pp.33-40
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• 2015

Forests are to be recognized as an important carbon sink under the UNFCCC that consist of above- and below-biomass, dead organic matter (DOM) such as dead wood and litter, and soil organic matter (SOM). In order to asses for DOM and SOM, however, it is relevant to land-use change matrices over last 20 years for each land-use category. In this study, a land-use change matrix was produced and its uncertainty was assessed using a point sampling technique with permanent sample plots in national forest inventory at Chungbuk province. With point sampling estimated areas at 2012 year for each land-use category were significantly similar to the true areas by given six land-use categories. Relative standard error in terms of uncertainty of land-use change among land-use categories ranged in 4.3~44.4%, excluding the other land. Forest and cropland covered relatively large areas showed lower uncertainty compared to the other land-use categories. This result showed that selected permanent samples in the NFI are able to support for producing land-use change matrix at a national or province level. If the $6^{th}$ NFI data are fully collected, the uncertainty of estimated area should be improved.

• Progress in Medical Physics
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• 제7권1호
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• pp.79-89
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• 1996

The purpose of this study was to examine the dead time effects and derive the correction factor. Using the thyroid probe and lucite cylindrical phantom, $^{99m}Tc$ 10.50mCi and $^{123}I$ 2.08mCi were counted with medical spectrometer at intervals of 2 hours for 43hrs and 79 hours. respectively. $^{123}I$ 2.06mCi was counted at intervals of 6 hours for 910 hours. To measure the starting point of dead time effect, the radioactivity was measured with dose calibrator in each time. The dead time effects started at about 0.80mCi at all distances for $^{99m}Tc$, and about 1.00mCi for $^{123}I$. The radioactivity corresponding to 20％ counts loss is 1.29(center), 1.28(2cm), 1.31(4cm), 1.13(6cm)mCi for $^{99m}Tc$ and 1.39mCi for $^{123}I$. The correction factors for 2mCi of radioactivity as an example were 1.52(center), 1.52(2cm), 1.50(4cm), 1.58(6cm) for $^{99m}Tc$ and 1.58 for $^{123}I$.

• Journal of Biosystems Engineering
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• 제32권5호
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• pp.284-291
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• 2007

This study was to investigate performance of position, basic controls and additional control for man-machine interface on a 3-point hitch of a tractor. The developed additional control was one-touchup, backup, turnup, liftarm limited, PTO on/off and an external control. As a result of experiment, maximum steady state error of response system was lower than $0.8^{\circ}$ and this result showed the function operated normally because the dead band of system set was ${\pm}1^{\circ}$. There was no abnormal situation by switch operation and sensor signal during the performance test. The results of experiment showed the characteristics of the response was sufficient to be used as the position and additional control system for tractors.

• Journal of Power Electronics
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• 제19권1호
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• pp.119-133
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• 2019

Although the dual modulation wave method can solve the low-frequency neutral point potential (NPP) fluctuation problem for three-level neutral point clamped converters, it also increases the switching frequency and limits the zero-sequence voltage. That makes it harmful when dealing with the NPP drift problem if the converter suffers from a long dead time or asymmetric loads. By introducing two degrees of freedom (2-DOF), an NPP control based on a search optimization method can demonstrate its ability to cope with the above mentioned two types of NPP problems. However, the amount of calculations for obtaining an optimal 2-DOF is so large that the method cannot be applied to certain industrial applications with an inexpensive digital signal processor. In this paper, a novel optimal 2-DOF-based NPP control is proposed. The relationships between the NPP and the 2-DOF are analyzed and a method for directly determining the optimal 2-DOF is also discussed. Using a direct calculation method, the amount of calculations is significantly reduced. In addition, the proposed method is able to maintain the strongest control ability for the two types of NPP problems. Finally, some experimental results are given to confirm the validity and feasibility of the proposed method.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.586-590
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• 1990

In this paper we describe the shape measuring technique and system with a non-contractive sensor, composed of slit-ray projector and solid-state camera. For improving the accuracy and preventing measuring dead point, this sensor part is attached to the end of robot, and each sensing is executed after one step moving. By patching these sensing data, whole measuring data is constructed. The calibration between sensor and world coordinate is implemented through the specific calibration block by transformation matrix method. The result of experiment was satisfactory.

• Structural Monitoring and Maintenance
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• 제4권1호
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• pp.17-31
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• 2017

Since extensometers are used to determine the absolute deformation of foundation and abutments and all results are obtained in reference to the base rod, the accuracy of these results has been constantly a subject of debate. In this regard, locating and installing extensometers outside the range of effect zone is also another challenge. The main purpose of this paper is to investigate and modify extensometers results based on the mentioned issues. For this aim, the concrete RCC Zhaveh dam in Iran was selected as the case study. To study the results of extensometers installed in this dam, first, the 3DEC_DP 5.00 software was applied for numerical modeling. Parameters such as discontinuities, dead load and piezometric pressure in the interface of concrete and rock were considered. Next, using the results obtained from 6 extensometers in foundation and abutments and 4 clinometers in dam body, the numerical model was calibrated through back analysis method. The results indicate that the base rod is moved and is not recommended being used as the base point. In other words, because installation of base anchor outside the range of effect zone is not possible due to the operational and economic considerations, the obtained results are not accurate enough. The results indicate a considerable 2-3 mm displacement of the base rod (location of the base anchor) in reference to the real zero point location, which must be added to the base rod results.

• Journal of Korean Society for Geospatial Information Science
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• 제3권2호
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• pp.213-220
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• 1995

Map Matching is the method for correcting the current position from dead reckoning in Car Navigation System. In this paper, we proposed the new map matching algorithm that can correct the positioning error caused by sensors and digital map data around the cross road area. To do this, first we set the error boundary of the cross road area by combining the relative error of moving distance and the absolute error of road length, second, we find out the starting point of turning within the determined error boundary of the cross point area, third, we compare the turning angle of the car to the angle of each possible road, and the last, we decide the matched road. We used wheel sensor as a speed sensor and used optical fiber gyro as a directional sensor, and assembled the sensors to the notebook computer. We testified our algorithm by driving the Daejeon area-which is a part of south Korea-as a test area. And we proved the efficiency by doing that.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.1105-1109
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• 1995

A CCD-camera, which is structured with vision system, was used to realize automatic seam-tracking system and 3-D information which is needed to generate torch path, was obtained by using laser-slip beam. To extract laser strip and obtain welding-specific point, Adaptive Hough-transformation was used. Although the basic Hough transformation takes too much time to process image on line, it has a tendency to be robust to the noises as like spatter. For that reson, it was complemented with Adaptive Hough transformation to have an on-line processing ability for scanning a welding-specific point. the dead zone,where the sensing of weld line is impossible, is eliminated by rotating the camera with its rotating axis centered at welding torch. The camera angle is controlled so as to get the minimum image data for the sensing of weld line, hence the image processing time is reduced. The fuzzy controller is adapted to control the camera angle.