• Journal of Applied Reliability
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• v.14 no.4
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• pp.225-229
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• 2014

A one-shot device is defined as a product, system, weapon, or equipment that can be used only once. After use, the device is destroyed or must undergo extensive rebuild. Determining the reliability of a one-shot device poses a unique challenge to the manufacturers and users due to the destructive nature and costs of the testing. This paper presents a reliability growth prediction for a one-shot system. It is assumed that 1) test duration is discrete(i.e. trials or rounds); 2) trials are statistically independent; 3) the number of failures for a given system configuration is distributed according to a binomial distribution; and 4) the cumulative expected number of failures through any sequence of configurations is given by AMSAA model. When the system development is represented by three configurations and the number of trials and failures during configurations are given, the AMSAA model parameters and reliability at configuration 3 are estimated by using a reliability growth analysis software. Further, if the reliability growth predictions do not meet the target reliability, the sample size of an additional test is determined for achieving the target reliability.

• Imaging Science in Dentistry
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• v.49 no.1
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• pp.35-43
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• 2019

Purpose: The goal of this study was to assess the accuracy and reliability of a low-cost portable scanner (Scanify) for imaging facial casts compared to a previously validated portable digital stereophotogrammetry device (Vectra H1). This in vitro study was performed using 2 facial casts obtained by recording impressions of the authors, at King's College London Academic Centre of Reconstructive Science. Materials and Methods: The casts were marked with anthropometric landmarks, then digitised using Scanify and Vectra H1. Computed tomography (CT) scans of the same casts were performed to verify the validation of Vectra H1. The 3-dimensional (3D) images acquired with each device were compared using linear measurements and 3D surface analysis software. Results: Overall, 91% of the linear Scanify measurements were within 1 mm of the corresponding reference values. The mean overall surface difference between the Scanify and Vectra images was <0.3mm. Significant differences were detected in depth measurements. Merging multiple Scanify images produced significantly greater registration error. Conclusion: Scanify is a very low-cost device that could have clinical applications for facial imaging if imaging errors could be corrected by a future software update or hardware revision.

• Journal of Biosystems Engineering
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• v.23 no.4
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• pp.381-390
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• 1998

An algorithm to extract the 3-D geometric information of a static object was developed using a set of 2-D computer vision system and a laser structured lighting device. As a structured light pattern, multi-parallel lines were used in the study. The proposed algorithm was composed of three stages. The camera calibration, which determined a coordinate transformation between the image plane and the real 3-D world, was performed using known 6 pairs of points at the first stage. Then, utilizing the shifting phenomena of the projected laser beam on an object, the height of the object was computed at the second stage. Finally, using the height information of the 2-D image point, the corresponding 3-D information was computed using results of the camera calibration. For arbitrary geometric objects, the maximum error of the extracted 3-D feature using the proposed algorithm was less than 1~2mm. The results showed that the proposed algorithm was accurate for 3-D geometric feature detection of an object.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.7
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• pp.308-314
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• 2005

The 2 GHz film bulk acoustic wave resonator(FBAR), one of the most necessary device of the next generation mobile communication system, consisted of solidly mounted resonator(SMR) structure using Brags reflector, was researched in this paper The FBAR applied SiO$_{2}$ and W had large difference of the acoustic impedance to reflector Al to electrode and ZnO to piezoelectric layer. Specially, the FBAR applied the two-step deposition method to improve the c-axis orientation and increase reproducibility of the fabrication device had good performance. The electrical properties of plasma such as impedance, resistance, reactance, $V_{pp},\;I{pp}$, VSWR and phase difference of voltage and current, was analyzed and measured by RF sensor with the variable experiment process factors such as gas ratio, RF power and base vacuum level about concerning the thickness, c-axis orientation, adhesion and roughness. The FBAR device about the optimum condition resulted reflection loss(S$_{11}$) of -17 dB, resonance frequency of 1.93 GHz, electric-mechanical coefficient(k$_{eff}$) of 2.38 $\%$ and Qualify factor of 580. It was seen better qualify than the common dielectric filter at present and expected on business to the filter device of 2 GHz bandwidth with the MMIC technology.

• Journal of Sensor Science and Technology
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• v.8 no.2
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• pp.163-170
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• 1999

A programmable A/D converter for an embedded fiber-optic combustion pressure sensor has been designed with 8 N and P channel MOSFETs, respectively. A local field enhancement for reducing programming voltage during writing as well as erasing an EEPROM device is introduced. In order to observe linear programmability of the EEPROM device during programming mode, a cell is developed with a $1.2\;{\mu}m$ double poly CMOS fabrication process in MOSIS. It is observed that the high resolution, of say 10mVolt, is valid in the range 1.25volts to 2volts. The experimental result is used for simulating the programmable 8 bit A/D converter with Hspice. The A/D converter is demonstrated to consume low power, $37\;{\mu}W$ by utilizing a programming operation. In addition, the converter is attained at the conversion frequency of 333 MHz.

• Nanomaterials
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• v.10 no.4
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• pp.764-767
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• 2020

Since the great success of graphene, atomically thin layered nanomaterials-called two-dimensional (2D) materials-have attracted tremendous attention due to their extraordinary physical properties. In particular, van der Waals heterostructured architectures based on a few 2D materials, named atomic scale Lego, have been proposed as unprecedented platforms for the implementation of versatile devices with a completely novel function or extremely high performance, shifting the research paradigm in materials science and engineering [1]. Thus, diverse 2D materials beyond existing bulk materials have been widely studied for promising electronic, optoelectronic, mechanical, and thermoelectric applications. In particular, this Special Issue includes the recent advances in unique preparation methods, such as exfoliation-based synthesis and the vacuum-based deposition of diverse 2D materials, as well as their device applications based on their interesting physical properties. This editorial consists of the following two sections: Preparation Methods of 2D Materials and Properties of 2D Materials.

• Korean Journal of Optics and Photonics
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• v.10 no.3
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• pp.248-253
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• 1999

In this paper, we have investigated a fiber type active coupler which utilizes the mode coupling between the side polished single mode optical fiber and the active multimode planar waveguide. The proposed device can be used for not only tunable wavelength filter or optical intensity modulator but also a tool for measuring optical properties of guiding material such as refractive index, birefringence, electro-optic coefficient, and thermo-optic coefficient. We gave designed and optimized a coupler structure using the BPM and fabricated the device using thermo-optic polymer as active planar waveguide overlay. The device showed that insertion loss was less then 0.5 dB, extinction ratio was -13 dB at the resonance wavelength, and the wavelength tunablity due to thermo-optic effect was -1.5 nm/$^{\circ}C$. The active coupler using thermo-optic effect can be used as a wavelength tunable filer, an optical intensity modulator and an optical sensor. pulses that are subsequently compressed by a dispersive optical fiber. Experimental results show that $sech^2$ shape pulses with a pulse width of ~14 ps and a time bandwidth product of ~0.34 are successfully generated at 10 GHz repetition rate. In contrast to other methods, such as higher order soliton compression, this approach does not depend on the optical power and thus shows promise for application to low-power lasers.

• Korean Journal of Computational Design and Engineering
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• v.15 no.3
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• pp.222-233
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• 2010

Developed in this research is a TP (tangible prototyping) system, which consists of two modules; (1) a virtual reality model to evaluate the functions and appearance of the product, and (2) a haptic device to emulate tactile and kinesthetic properties of mechanical dial knobs. As an example, a washing machine is modeled using a commercial CAD system and transformed in VRML and X3D formats. Some dynamic behaviors and kinematic characteristics are programmed using X3D script and Java. Various haptic behaviors of the dial are generated by modulating torque profile according to the rotation angle. A torque profile measuring system is developed to evaluate the behaviors of the haptic dial physically. Haptic sensibility evaluations are accomplished using the TP by semantic differential method.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.4
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• pp.514-519
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• 2006

SrS:Cu, Cl thin films have been grown by the hot wall technique with S furnace placed on the outside of the growth chamber in order to investigate the crystallographic and optical characteristics. The films have a good crystallinity independent of CuCl wall temperature and PL characteristics showed a peak assigned by the transition form $3d^94s^1\;(^3Eg)$ to $3d^{10}\;(^1A_{1g})$ of $Cu^+$ center. It has also been found that. from the PLE spectra, $Cu^+$ luminescent centers are doped in the host materials. The EL emission from SrS:Cu-based device showed a greenish-blue but shifted to short wavelength compared to SrS:Ce-based EL. The device was obtained the maximum luminance of $110cd/m^2$ and the maximum luminous efficiency of $0.1\;lm/W$ at $V_{40}$.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.12
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• pp.60-68
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• 1993

Thw VLSI device of submicron level trends to have a low level of reliability because of hot carriers which are caused by short channel effects and which do not appear in a long-channel MOSFET operated in 5V. In order to minimize the generation of hot carrier, much research has been made into various types of drain structures. This study has suggested CG MOSFET (Concaved Gate MOSFET) as new drain structure and compared its electrical characteristics with those of the conventional MOSFET and LDD-structured MOSFET by making use of a simulation method. These three device were assumed to be produced by the LOCOS process and a computer-based analysis(PISCES-2B simulator) was carried out to verify the hot electron-resistant behaviours of the devices. In the present simulation, the channel length of these devises was 1.0$\mu$m and their DC characteristics, such as VS1DT-IS1DT curves, gate and substrate current, potential contours, breakdown voltage and electric field were compared with one another.