• IEIE Transactions on Smart Processing and Computing
• /
• v.3 no.6
• /
• pp.425-429
• /
• 2014

This paper proposes a DC-DC Buck-Converter with DT-CMOS (Dynamic Threshold-voltage MOSFET) Switch. The proposed circuit was evaluated and compared with a CMOS switch by both the circuit and device simulations. The DT-CMOS switch reduced the output ripple and the conduction loss through a low on-resistance. Overall, the proposed circuit showed excellent performance efficiency compared to the converter with conventional CMOS switch. The proposed circuit has switching frequency of 1.2MHz, 3.3V input voltage, 2.5V output voltage, and maximum current of 100mA. In addition, this paper proposes a SCP (Short Circuit Protection) circuit to ensure reliability.

• Proceedings of the KIEE Conference
• /
• 1997.11a
• /
• pp.618-620
• /
• 1997

A $50{\times}50{\mu}m^2$ aluminum micromirror array is fabricated using shadow evaporation process. The fabrication process is very simple with use of shadow evaporation process, and the micromirror array has a high fill-factor. The static and dynamic characteristics such as deflection angle vs. applied voltage, step response, and frequency response are measured using a contact free optical measurement technique. The downward threshold voltage was 8 V, step response time was $13.5{\mu}s$ when 32 V step voltage applied, and a resonance observed at 11kHz. The lifetime of micromirror with anti-stiction coating was tested and micromirror operated successfully over 200 million cycles of touch-down operations.

• Journal of applied mathematics & informatics
• /
• v.29 no.3_4
• /
• pp.721-741
• /
• 2011

In this paper we have considered a dynamical mathematical model of the sub-populations of potential smokers (non-smokers), smokers, smokers who temporarily quit smoking, smokers who permanently quit smoking and a class of smoking associated illness by introducing time dependent parameters and distributed time delay to acquire smoking habit. Here, we have established some sufficient conditions on the permanence and extinction of the smoking class in the community by using inequality analytical technique. We have introduced some new threshold values $R_0$ and $R^*$ and further obtained that the smoking class in the community will be permanent when $R_0$ > 1 and the smoking class in the community will be going to extinct when $R^*$ < 1. By Lyapunov functional method, we have also obtained some sufficient conditions for global asymptotic stability of this model. Computer simulations are carried out to explain the analytical findings. The aim of the analysis of this model is to identify the parameters of interest for further study, with a view to informing and assisting policy-maker in targeting prevention and treatment resources for maximum effectiveness.

• Journal of Korea Water Resources Association
• /
• v.33 no.S1
• /
• pp.101-110
• /
• 2000

This paper introduces the equivalent frequency response method(EFRM) into runoff analysis. This EFRM originally had been developed to analyze dynamic behavior of nonlinear elements such as threshold and saturation in control engineering. Many runoff models are described by nonlinear ordinary of partial differential equations This paper presents that these nonlinear differential equations can be converted into semi-linear ones based on EFRM. The word of "a semi-linear equation" means that the coefficients of derived equations depend on average rainfall.

• The KIPS Transactions:PartC
• /
• v.11C no.3
• /
• pp.345-352
• /
• 2004

Recently, contents distribution technologies have been used to cope with the explosive demand for Web services. In this paper, we addressed the issue of the optimal placement of replicas in the environment where Web contents are replicated. We placed replicas so that clients can have access to replicas with the proper delay and bandwidth. We attempted to solve the problem via dynamic programming considering cost of delay and traffic We have come up with time complexity that is less than $O(n^2)$. We defined the threshold and proved that our algorithm guarantees the reliable services.

• Proceedings of the KIEE Conference
• /
• 2002.11c
• /
• pp.609-612
• /
• 2002

In this paper, a 12-bit 100-MHz CMOS current steering digital-to-analog converter is designed. In the D/A converter, a driver circuit using a dynamic latch is implemented to obtain low glitch and thermometer decoder is used for low DNL errors, guaranteed monotonicity, reduced stitching noise. And a threshold voltage-compensated current source. The D/A converter is designed with 0.35-$\mu m$ CMOS technology at 3.3 V power supply and simulated with HSPICE. The maximum power dissipation of the designed DAC is 143 mW.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.22 no.1
• /
• pp.104-115
• /
• 1997

This paper investigates PN code acquistion algorithm and demodulation performance of the RAKE receiver in the DS/CDMA(direct sequence code division multiple access) sysytems under a multipath fading channel with multiusers. To speed up the acquisition process, PN matched filter is applied and postdetection integration technique comable withthe dynamic threshold set method is proposed. the Maximum-Likelihood algorithmin serial fashion is able to find PN code delay estimates for the RAKE branches using sliding window in a multipath fading channel. The correct acquistion probability and mean acquistion time are used as a performance measure of the system using the Monte Carlo method. The performance of the RAKEreceiver, afte the code acquisition is achieved is the CDMA systems, is also investigated for three major combining techniques.

• Journal of Korean Vacuum Science & Technology
• /
• v.3 no.1
• /
• pp.66-73
• /
• 1999

In this paper, the design of one-chip FED system integrated with driving circuits in reported on the basis of MOSFET controlled FEA (MCFEA). To integrate a MOSFET with a FEA efficiently, a new fabrication process is proposed. It is confirmed that the MOSFET with threshold voltage of about 2volts controls the FEA emission current up to 20 ${\mu}$A by applying driving voltage of 15 volts, which is enough current level to utilize the MCFEA as a pixel for FED. The drain breakdown voltage of the MOSFET is measured to be 70 volts, which is also high enough for 60 volt operation of FED. The circuits for row and column driver are designed stressing on saving area, reducing malfunction probability and consuming low power to maximize the merit of on-chip driving circuits. Dynamic logic concept and bootstrap capacitors are used to meet these requirements. By integrating the driving circuit with FEA, the number of external I/O lines can be less than 20, irrespectively of the number of pixels.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2000.01a
• /
• pp.37-38
• /
• 2000

The ZnS:Tb thin-film electroluminescent devices were grown by atomic layer deposition with utilizing single-layer aluminum oxide and/or multilayered tantalum aluminum oxide, $Ta_xAl_yO$, as upper and lower insulating layers. These devices were investigated in terms of the luminescent and electrical characteristics. From this analysis, the devices using the $Ta_xAl_yO$ instead of $Al_2O_3$ were observed to have a lower threshold voltage for emission due to the higher relative dielectric constant of $Ta_xAl_yO$ insulators than that of the $Al_2O_3$ device. And there was a large amount of dynamic space charge generation in the phosphor of the device with the $Ta_xAl_yO$ insulators seemingly due to electron multiplication such as trap ionization.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.54 no.4
• /
• pp.251-258
• /
• 2005

Automatic document classification may differ significantly according to the characteristics of documents that are subject to classification, as well as classifier's performance. This research identifies e-mail document's characteristics to apply a three-step preprocessing algorithm that can minimize e-mail document's atypical characteristics. In the first 5go, uncertain based sampling algorithm that used Mean Absolute Deviation(MAD), is used to address the question of selection learning document for the rule generation at the time of classification. In the subsequent stage, Weighted vlaue assigning method by attribute is applied to increase the discriminating capability of the terms that appear on the title on the e-mail document characteristic level. in the third and last stage, accuracy level during classification by each category is increased by using Naive Bayesian Presumptive Algorithm's Dynamic Threshold. And, we implemented an E-Mail Recommendtion System using a three-step preprocessing algorithm the enable users for direct and optimal classification with the recommendation of the applicable category when a mail arrives.