• Journal of Biosystems Engineering
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• v.28 no.4
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• pp.335-342
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• 2003

A simple disposable thick-film potentiometric strip has been developed and evaluated for hydroponics application. The strip consisted of low ion-selective electrodes (ISE) fabricated by screen-printing technology. The electrochemical responses of ion sensors for nitrate, ammonium, potassium, and magnesium were measured with specially designed 16-channel low voltage signal transducers. The analytical characteristics of the sensors were comparable with those of conventional ISE sensors. The thick-film sensors exhibit linear relationships over five concentration decades. The concentration of N $O_3$ - ion in standard solution can be determined by direct potentiometric measurements without any conditioning before measurements. However, measurement of $K^{+}$, N $H_4$$^{+}$, and $Mg^{2+}$ ionic concentrations in nutrient solutions seems not feasible.

• Journal of Power System Engineering
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• v.12 no.1
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• pp.72-79
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• 2008

This paper designs a looper-tension controller for mass-flow stabilization in hot strip finishing mills. By Newton's 2nd law and Hooke's law, nonlinear dynamic equations on the looper-tension system are firstly derived, and linearized by a linearization algorithm using a Taylor's series expansion. Moreover, a tension calculation model is obtained from the nonlinear dynamic equations which is called as a soft sensor of strip tension between two neighboring stands. Next, a looper-tension servo controller is designed by an ILQ(Inverse Linear Quadratic optimal control) algorithm, and it is combined with a minimal disturbance observer which to attenuate speed disturbances by AGC and operator interventions, etc.. Finally, it is shown from by a computer simulation that the proposed ILQ controller with a disturbance observer is very effective in stabilizing the strip mass-flow under some disturbances, moreover it has a good command following performance.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.7 no.3
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• pp.193-200
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• 1996

In this paper, Strip Halo Antenna used for the proximity sensor in 800 MHz band was fabricated by using a dielectric board with the relative dielectric constant of 6.15. Dimensions of the strip halo antenna were optimized by the theoretical simulation and many experiments. The impedance of the strip halo antenna mounted on the proximity sensor with the finite circular groud plane was measured as 16.5 + j1.1[$\Omega$]. The matching characteristic of the strip halo antenna was greatly improved by attaching the matching section designed through experiments to the rear side of dielectric board. The impedance of the strip halo antenna with the matching section was measured as 43.79-j0.04[$\Omega$], and the 3 dB beam width of its radiation pattern was measured about $90^{\circ}$.

• Applied Chemistry for Engineering
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• v.22 no.5
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• pp.522-525
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• 2011

In this study, an established enzyme-linked immunosorbent assay and immuno-chromatography technique are combined to fabricate an immuno-strip sensor for the detection of S. aureus. The immuno-strip is manufactured by using four different functional membranes. The capture antibody is immobilized on the nitrocellulose membrane due to the high affinity and the capillary action through porous membranes induces a flow of sample. A colorimetric signal is appeared according to the enzyme reaction and is analyzed by the digital camera (qualitative analysis) and home-made image analysis software (quantitative analysis). Under the optimal conditions, samples with S. aureus in the range of $2.7{\times}10^4{\sim}2.7{\times}10^7CFU/mL$ can be detected by the colorimetric method within 30 min.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.350-354
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• 1995

The Tension Leveller of Cold Rolling Mill In POSCO performs levelling the strip in high speed line. But minor variations in operating condition of driving machines such as motor, gear box, and support bearings, a small gap-variation of supporter and strip slip by poor roll revolutions can cause serious problems in the quality of strip. In this study, firstly, A condition monitoring standard for each sensor is made through with the detail analysis of vibration and strip slip. Secondly, An automatic monitoring and diagnosing system was developed to monitor the condition of Tension Leveller, and diagnose the cause of abnormal condition. Finally, A diagnosing algorithm for abnormal condition and man-machine interface (MMI) for easy operation are developed.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.75.5-75
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• 2001

In this paper, we study design of a ILQ(Inverse Linear Quadratic optimal control) looper control system for hot strip mills. The looper which is placed between stands plays an important role in controlling strip width by regulating strip tension variation generated from the velocity difference of main work rolls. A Looper servo controller is designed by ILQ control theory which is an inverse problem of LQ(Linear Quadratic optimal control) control. The mathematical model for looper system is obtained by Taylor´s linearization of nonlinear differential equations. Then we designed linear controller for linearization model by using the ILQ control algorithm. Thereafter this controller is applied to the nonlinear model for model identification. As a result, we show the controller´s robustness for the model error, external disturbance and sensor noise.

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.37-40
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• 2008

The purpose of this paper is to extract DEMs from Spot-3 strips using orbit modeling technique. Spot-3 stereo strip images along 420km in distance were used for experiments. The orbit modeling technique has been suggested to establish accurate geometric models for a whole strip taken on the same orbit using only a small number of GCPs on the top area of the strip. This method enables extraction of orientation parameters of the scene along the strip that is needed to generate DEMs. Consequently, we were able to extract DEMs over the areas without accurate GCPs obtained by GPS surveying per each scene. Assessment of accuracy was carried out using USGS DTED. DEMs generated from the orbit modelling technique suggested showed satisfactory performance when quantitative analysis of accuracy assessment was carried out.

• Journal of the Korean Electrochemical Society
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• v.17 no.2
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• pp.130-137
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• 2014

A strip sensor based on $PbO_2$/carbon paste electrode was prepared by a screen-printing method, and employed to electrochemically determine the concentration of fruit sweeteners(i.e. glucose, sucrose, and fructose). The $PbO_2$/carbon paste electrode could monitor electrocatalytic oxidation of organic compounds such as carbohydrates, and measure the levels of natural sweeteners without enzyme. Severe interference from ascorbic acid was effectively reduced by modifying the electrode surface with a Nafion membrane. The response level of the Nafion/$PbO_2$/carbon paste electrode increased in the order of fructose, sucrose, and glucose, which corresponds to the order of sweetness perceived by humans.

• Smart Structures and Systems
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• v.6 no.9
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• pp.1007-1023
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• 2010

This paper describes the development and evaluation of an innovative TDR distributed moisture sensor. This sensor features advantages of being responsive to the spatial variations of the soil moisture content. The geometry design of the sensor makes it rugged for field installation. Good linear calibration is obtained between the sensor measured dielectric constant and soil physical properties. Simulations by the finite element method (FEM) are conducted to assist the design of this sensor and to determine the effective sampling range. Compared with conventional types of moisture sensor, which only makes point measurement, this sensor possesses distributed moisture sensing capability. This new sensor is not only easy to install, but also measures moisture distribution with much lower cost. This new sensor holds promise to significantly improve the current field instruments. It will be a useful tool to help study the influence of a variety of moisture-related phenomena on infrastructure performance.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.180-180
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• 2000

The shape of cold strip for the stainless process has been become issue in quality recently, and hence POSCO (Pohang Iron & Steel Co., Ltd) developed an automatic control system for strip shape in the sendzimir mill. The strip shape is measured by an outward measuring roll and is controlled by As_U roll and first intermediate roll. As_U roll consists of 8 saddles, which are controlled vertically. The fist intermediate rolls, which are controlled horizontally, consist of two pairs of rolls up and down. A developed shape control system is applied to real plant by using fuzzy logic and neural network method to control actuators; As_U roll and first intermediate roll. This system composes mainly of three parts as a real-time system, input to output conditioner board, and man-machine interface. The actual shape is recognized by neural network and converted into symmetric shape. The fuzzy controller, based on the shape from neural network and sensor, controls positions of the As_U roll and first intermediate roll. This paper verifies the shape controller performance. The experiments are made on line for the sendzimir mill. The shape control performance shows very efficient for the target tracking, shape symmetry, and fluctuation of shape.