• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2000.04a
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• pp.110-110
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• 2000

Cantilever-shaped lateral field emitters were fabricated and their electrical characteristics were tested. As shown in Fig.1, poly-silicon cantilevers were fabricated by the surface micromachining and they were used to the vacuum magnetic field sensors. The tunneling devices were vacuum sealed with the tubeless packaging method, as shown in Fig.2 and Fig.3. The soda-lime glasses were used for better encapsulation, so the sputtered silicon and the glass layers on the soda-lime glasses were bonded together at 1x10$^{-6}$ Torr. The getter was activated after the vacuum sealing fur the stable emissions. The devices were tested outside of the vacuum chamber. Through vacuum packaging, the tunneling sensors can be utilized. Fig.4 shows that the sensor operates with the switching of the magnetic field. When the magnetic field was applied to the device, the anode currents were varied by the Lorentz force. The difference of anode currents can be varied with the strength of the applied magnetic field.

• International journal of advanced smart convergence
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• v.2 no.1
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• pp.1-5
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• 2013

This study proposes a remote monitoring of patients and emergency notification system with a camera and pulse wave sensor for U-Healthcare. The proposed system is a server client model based U-Healthcare system which consists of wireless clients that have micro-controller, embedded-board for patient status monitoring and a remote management server. The remote management server observes the change of pulse wave data individually in real-time sent from the clients that is to be remote-monitored based on the pulse wave data stored by users and divides them into caution section and emergency section. When the pulse wave data of a user enters an emergency situation, the administrator can make a decision based on the real-time image information and pulse rate variability. When the status of the monitored patient enters the emergency section, the proposed U-healthcare system notifies the administrator and relevant institutions. An experiment was conducted to demonstrate the pulse wave recognition of the proposed system.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1499-1500
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• 2008

최근에 LCD의 후면광원으로 LED를 채용하는 경우가 증가하고 있다. 이러한 LED를 Back Light으로 사용할 경우 일정한 휘도의 유지와 색좌표의 보정은 고급제품의 경우 채용이 증가하고 있다. 본 연구에서는 LCD Monitor용 LED BLU의 CMS(Color Management System)을 개발하기 위하여 1.5W R,G,G,,B가 하나의 PKG에 들어있는 LED를 이용하여 Direct type의 Back Light Unit을 개발하였다. 방열 및 휘도 균일도를 고려하여 LED part를 설계, 개발하였고 LED를 PWM으로 구동하기 위하여 Switching circuit이 포함되는 구동회로 부분을 설계, 개발 하였다. 또한 Color Sensor와 CMS IC를 사용하여 Color를 Control하고 휘도도 컨트롤하는 제어회로 부분도 개발을 하였다. CMS 기능의 제어회로 부분을 개발하기 위하여 MicroController를 사용하였으며 CMS IC와의 통신을 위한 부분도 개발하였다. 이러한 구성을 개발하여 시제품을 직접 제작하였다. 평가를 위하여 성능시험을 실시하였고 광학적인 평가도 시행하였다. 제작된 시제품은 L558 x W359 x H30 으로 하였다. 휘도는 목표휘도를 이루었으며 균일도는 85% 이상이 되었다.

• Journal of Advanced Navigation Technology
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• v.16 no.5
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• pp.839-845
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• 2012

This paper deals with the design and development of the remote control and measurement systems by Embedded Web Server. The remote control and measurement systems are implemented by Cortex M-3 ARM micro-controller. The user application software for the control and measurement system user, and the firmware software of device drivers for peripherals such as a digital input/output device, AD/DAC(Analog to Digital/Digital to Analog Converter), LCD, and temperature/humidity sensor are developed in Eclipse environment using Codesourcery C, Java script, and HTML. The experimental result of the proposed control and measurement systems implemented in this paper is evaluated via real-time experiments, which works well as designed.

• Journal of Advanced Navigation Technology
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• v.12 no.6
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• pp.653-658
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• 2008

The automotive environment is particularly demanding on connector performance, and is characterized by large temperature changes, high humidity and corrosive atmospheres. Fretting is a contact damage process that occurs between two contact surfaces. Fretting corrosion refers to corrosion damage at the asperities of contact surfaces. This damage is induced under load and in the presence of repeated relative surface motion, as induced for example by vibration. This paper critically reviews the works published previously on fretting corrosion of electrical connectors. Various experimental approaches such as testing machines, material selection, testing environments, acceleration testing techniques and preventing methods are addressed. Future research prospects arc suggested.

• Korean Journal of Computational Design and Engineering
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• v.17 no.3
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• pp.156-163
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• 2012

Real-time three-dimensional shape measurement is becoming increasingly important in various fields, including medical sciences, high-technology industry, and microscale measurements. However, there are not so many 3D profile tools specially designed for specifically narrow space, for example, to scan the tooth shape of a human jaw. In this paper, a real-time 3D intraoral scanner is proposed for the measurement of tooth profile in the mouth cavity. The proposed system comprises a laser diode beam, a micro charge-coupled device, a graticule, a piezoelectric transducer, a set of optical lenses, and a polhemus device sensor. The phase-shifting technique is used along with an accurate calibration method for the measurement of the tooth profile. Experimental and theoretical inspection of the phase-to-coordinate relation is presented. In addition, a nonlinear system model is developed for collimating illumination that gives the more accurate mathematical representation of the system, thus improves the shape measurement accuracy. Experiment results are presented to verify the feasibility and performance of the developed system. The experimental results indicate that overall measurement error accuracy can be controlled within 0.4 mm with a variability of ${\pm}0.01$.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.189.1-189.1
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• 2014

Lead zirconium titanate (PZT) is usually used as bulk and thin films. Due to high flexibility and piezoelectric, ferroelectric and pyroelectric properties, PZT fiber has attracted in a variety of fields such as sensor devices, non-electromechanical systems and non-volatile ferroelectric memory devices. And PZT fiber can be numerously synthesized and almost with the diameter of PZT fiber thicker than $10{\mu}m$. However, the electrospinnig method is cost effective and convenient. PZT obtained by electrospinning methodhas the diameter from sub-micro to nanometer. In this paper, the PZT/PVP nanofibers were synthesized with three precursors, lead nitrate, zirconium ethoxide and titanium isopropoxide. And the PZT nanofibers were fabricated after removal of PVP by annealing process at various temperature. The obtained PZT nanofibers were characterized by means of X-ray photoelectron spectroscopy (XPS) for chemical properties, X-ray diffraction (XRD) for crystallinity and phase, scanning electron microscopy (SEM) for morphologies. The diameter of PZT nanofibers were measured with SEM. From the SEM images, we confirmed that diameter of PZT nanofibers was hundreds of nanometers and decreased with increasing the annealing temperature. When the annealing temperature increased, the crystallinity of PZT nanofibers changed from pyrochlore to perovskite structure.

• KIEAE Journal
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• v.6 no.4
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• pp.25-32
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• 2006

Mock-up model can be applied to measure accurate performance data but difficult to apply the variables in experiment. There can be a slight experiment errors in Scale model, but various parameters can be applied for a objective experiment. This paper aims to compare the daylighting performance in 1, 1/5, 1/10 scale model of offices and analyze the experiment errors to certificate the influence of model experiment. To analyse daylighting performance, a comparison of a Mock-up model, sized $12.0m(w){\times}7.2m(l){\times}3.7m(h)$, designed for experimentation of daylighting systems and its 1:5, 1:10 scale model. It has an identical configuration of reference room and the test room. For the test room, the lightshelf system was designed as Micro-4 reflective material. To assess work plane illuminance and light factor, photometric sensors of each room were installed at work-plane(6 points) and exterior horizontal illuminance (1 point). And luminance of window, rare of the room was measured under clear sky. It is to be monitored by Agilent data logger, photometric sensor Li-cor and the Radiant Imaging ProMetric 1400. Comparisons with a light factor, increase-decrease ratio and luminance are discussed.

• Journal of Sensor Science and Technology
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• v.21 no.1
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• pp.53-58
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• 2012

Biological and chemical assays(e.g., clinical tests for medical diagnosis) are needed to handle small liquid volume with high accuracy and high reliability. Many micro-dispensing systems using various actuation methods have been developed and applied. In this research, we confirm repeatability of the cartridge-type dispensing system with various measuring methods for guarantee of an acceptable reliability. We systematically examine the dispensed volume variation and dispense rate during 500,000 shots of sequential actuation. Using the same method, we confirm the repeatability of dispensed volume while varying operating conditions and design parameter(i.e., outlet size) of the dispensing system. Also, we examine the consistency of the dispensed volume of droplet while varying the operating pressures. Furthermore, we repeatedly measure differences between an actual dispensed volume and a target volume. According to our results, it is expected that the stable and reliable performance of our dispensing system can effectively be used in various applications containing bio-solutions.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.6
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• pp.539-546
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• 2014

This paper describes an ultra-precision electronic clinometer, which is based on the capacitive-based fluid type, for detection of small inclination angles. The main parts of the clinometer low-noise electronics are two capacitance measurement circuits for converting the capacitances of the capacitors of the clinometer into voltages, and a differential amplifier for obtaining the difference of the capacitances, which is proportional to the input inclination angle. A 16 bit analog to digital (AD) converter is also embedded into the same circuit board, whose output is sent to a PC via RS-232C, for achieving a small noise level down to tens of ${\mu}v$. A compensation method, which is referred to as the delay time method for shortening the stabilization time of the sensor was also discussed. Experimental results have shown the possibility of achieving a measurement resolution of $0.0001^{\circ}$ as well as the quick measurement with the delay time method.