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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of Sensor Science and Technology
Journal Basic Information
Journal DOI :
The Korean Sensors Society
Editor in Chief :
Volume & Issues
Volume 7, Issue 6 - Nov 1998
Volume 7, Issue 5 - Sep 1998
Volume 7, Issue 4 - Jul 1998
Volume 7, Issue 3 - May 1998
Volume 7, Issue 2 - Mar 1998
Volume 7, Issue 1 - Jan 1998
Selecting the target year
PZT5 spherical hydrophone simulation using a coupled FE-BE method
Jarng, Soon-Suck ;
Journal of Sensor Science and Technology , volume 7, issue 6, 1998, Pages 377~385
This paper describes the application of a coupled finite element-boundary element method to obtain the steady-state response of a hydrophone. The particular structure considered is a flooded piezoelectric spherical shell. The hydrophone is three-dimensionally simulated to transduce an incident plane acoustic pressure onto the outer surface of the sonar spherical shell to electrical potentials on inner and outer surfaces of the shell. The acoustic field formed from the scattered sound pressure is also simulated. And the displacement of the shell caused by the externally incident acoustic pressure is shown in temporal motion. The coupled FE-BE method is described in detail.
Phase Transition and Relaxation Properties of Nonlinear-Optical KTP Single Crystal
Choi, Byung-Chun ;
Journal of Sensor Science and Technology , volume 7, issue 6, 1998, Pages 386~393
We have carried out the measurements of complex dielectric constants with impedance/gain-phase analyzer using capacitor method and the experiments of high temperature X-ray powder diffraction with X-ray diffractometer using
scan method for the KTP single crystal which has the premium nonlinear optical properties. From the results of high temperature X-ray powder diffraction experiments, we have found that KTP does not undergo structural phase transition below
. It is clear that KTP undergoes structural phase transition around
and belongs to orthorhombic above
still. However, we have applied phenomenological relation of dielectric relaxation to the results of complex dielectric measurement and have found that relaxation mechanism of KTP well satisfies the Cole-Cole relation over the temperature range from
. And also the relaxation time well satisfies the Vogel-Fulcher relation. It is regarded that the hopping and thermally activated diffusion mechanism may control the conduction behavior of KTP above
A High Speed Vision Algorithms for Axial Motion Sensor
Mousset, Stephane ; Miche, Pierre ; Bensrhair, Abdelaziz ; Lee, Sang-Goog ;
Journal of Sensor Science and Technology , volume 7, issue 6, 1998, Pages 394~400
In this paper, we present a robust and fast method that enables real-time computing of axial motion component of different points of a scene from a stereo images sequence. The aim of our method is to establish axial motion maps by computing a range of disparity maps. We propose a solution in two steps. In the first step we estimate motion with a low level computing for an image point by a detection estimation-structure. In the second step, we use the neighbourhood information of the image point with morphology operation. The motion maps are established with a constant computation time without spatio-temporal matching.
An Automatic AC-DC Transfer Error Measurement System
Kwon, Sung-Won ; Cho, Y.M. ; Kim, K.T. ; Kang, J.H. ; Park, Y.T. ;
Journal of Sensor Science and Technology , volume 7, issue 6, 1998, Pages 401~408
A dual-channel automatic ac-dc voltage transfer error measurement system in which the output voltages of two thermal voltage converters which are ac voltage standard are directly measured at the same time to reduce the output voltage drift is described. Forward-reverse measurement method by using a two-channel scanner is used to cancel the offset voltage of the voltmeters. The agreements of the 4-V TVC comparison results between other national standards institute and Korea Research Institute of Standards and Science were less than about
in the frequency range of
, and were less than about
. Measurement uncertainty is reduced significantly from
of manual system to
of new system(up to 100 kHz) typically and great increase in comparison efficiency has been achieved by this system.
Color Temperature Measurement and Classification of Ambient Light Sources Using two Color Sensors, Yellow and Cyan
Choi, Duk-Kyu ; Kwon, Yong-Dae ; Kwon, Ki-Ryong ; Sohng, Kyu-Ik ;
Journal of Sensor Science and Technology , volume 7, issue 6, 1998, Pages 409~417
Originally, the reference white of the NTSC system used to be CIE illuminant C of 6774K. However, that of color television receiver has been adjusted to 9300K as a result of consumer preference for a very bluish white for monochrome television. Recent studies have revealed that the preferred color temperature of display white should be 3000K or 4000K higher than that of surround illuminant. Therefore it is required to classify ambient lighting source. In this paper, a efficient method that can distinguish the ambient incandescent lamp from fluorescent lamp under television viewing condition is developed using only two color sensors, yellow and cyan. Experimental results show that the proposed method is very useful for the discrimination of ambient lighting source, fluorescent of 6000K and incandescent lamp of 3000K. The system was also tested for mixture of these light sources.
Calibrating Stereoscopic 3D Position Measurement Systems Using Artificial Neural Nets
Do, Yong-Tae ; Lee, Dae-Sik ; Yoo, Seog-Hwan ;
Journal of Sensor Science and Technology , volume 7, issue 6, 1998, Pages 418~425
Stereo cameras are the most widely used sensing systems for automated machines including robots to interact with their three-dimensional(3D) working environments. The position of a target point in the 3D world coordinates can be measured by the use of stereo cameras and the camera calibration is an important preliminary step for the task. Existing camera calibration techniques can be classified into two large categories - linear and nonlinear techniques. While linear techniques are simple but somewhat inaccurate, the nonlinear ones require a modeling process to compensate for the lens distortion and a rather complicated procedure to solve the nonlinear equations. In this paper, a method employing a neural network for the calibration problem is described for tackling the problems arisen when existing techniques are applied and the results are reported. Particularly, it is shown experimentally that by utilizing the function approximation capability of multi-layer neural networks trained by the back-propagation(BP) algorithm to learn the error pattern of a linear technique, the measurement accuracy can be simply and efficiently increased.
The characteristics of electrochemical etch-stop in THAH/IPA/pyrazine solution
Chung, G.S. ; Park, C.S. ;
Journal of Sensor Science and Technology , volume 7, issue 6, 1998, Pages 426~431
This paper describes electrochemical etch-stop characteristics in THAH/IPA/pyrazine solution. I-V curves of n- and p-type Si in THAH/IPA/pyrazine solution were obtained. OCP(Open Circuit Potential) and PP (Passivation Potential) of p-type Si were -1.2 V and 0.1 V, and of n-type Si were -1.3 V and -0.2 V, respectively. Both n- and p-type Si, etching rates were abruptly decreased at potentials anodic to the PP. The etch-stop characteristics in THAH/IPA/pyrazine solution were observed. Since accurate etching stop occurs at pn junction, Si diaphragms having thickness of epi-layer were fabricated. Etching rate is highest at optimum etching condition, TMAH 25wt.%/IPA 17vol.%/pyrazine 0.1g/100ml. thus the elapsed time of etch-stop was reduced.
The electro-optical characteristics of PDLC
Kim, Won-Jae ; Park, Se-Kwang ;
Journal of Sensor Science and Technology , volume 7, issue 6, 1998, Pages 432~436
Recently, the PDLC(Polymer Dispersed Liquid Crystal) is being developed lively to make a large display device using a liquid crystal. Because of low light loss, high brightness, and simple fabrication process, it is made easily to large display device, In this study, the response time and light transmittance by the applied voltage is measured to analyze the electro-optical characteristics of PDLC. The He-Ne laser is applied to the PDLC cell, the light transmittance is measured using the photodiode and the result is analyzed and displayed graphically by the digital oscilloscope. The result of comparison between the PDLC and the present LCD is used to study the potential as a display device.
Design Method for Shape Memory Alloy Actuator with Bias Spring
Lee, Seung-Ki ; Na, Seung-Woo ;
Journal of Sensor Science and Technology , volume 7, issue 6, 1998, Pages 437~445
The actuator using shape memory alloy spring with bias spring can act as a bidirectional actuator due to the restoring force of the bias spring. In the design of shape memory actuator with bias spring, the required design specifications are the generated force and the necessary stroke. To fulfill these requirements, shape memory alloy spring and bias spring should be designed carefully considering the specified application. In this paper, the novel design method for shape memory alloy actuator with bias spring, which does not require any assumptions from experience, has been proposed and verified by the test of fabricated shape memory alloy actuator. The experimental results show good agreements with calculated values, which guarantees the practical validity of our proposed design method.
Mechanical Properties of Conductive Polymer as Actuator Materials with Change of Polymerization Condition
Choi, Young ; Lee, Seung-Ki ;
Journal of Sensor Science and Technology , volume 7, issue 6, 1998, Pages 446~451
Recently, conductive polymer is known to be direct-drive active material which can convert electrical energy directly into mechanical energy. In this paper, the polymerized thickness of polypyrrole is measured with change of polymerization conditions and the mechanical bending is analyzed for various polymerized thickness. In order to detect of mechanical bending, bending beam method using the bridge shaped sample is used. Thickness of polypyrrole is proportional to polymerization time in fixed current density. Also it shows a linear relation with the applied current except high current density. Maximum displacement appears at the thickness of
which has been polymerized at
and for 120min and actuated at the frequency of 0.1Hz.