• International Journal of Reliability and Applications
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• v.7 no.2
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• pp.141-153
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• 2006

In this paper, we present the U-Statistic test for testing exponentiality against new renewal better than used (NRBU) based on a goodness of fit approach. Selected critical values are tabulated for sample sizes n=5(1)30(10)50. The asymptotic Pitman relative efficiency relative to (NRBU) test given in the work of Mahmoud et all (2003) is studied. The power estimates of this test for some commonly used life distributions in reliability are also calculated. Some of real examples are given to elucidate the use of the proposed test statistic in the reliability analysis. The problem in case of right censored data is also handled.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.3
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• pp.44-53
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• 2008

In this paper, we present the design of delta-sigma modulation-based class-D amplifier for driving headphones in portable audio applications. The presented class-D amplifier generates PWM(pulse width modulation) signals using a single-bit fourth-order high-performance delta-sigma modulator. To achieve a high SNR(signal-to-noise ratio) and ensure system stability, the locations of the modulator loop filter poles and zeros are optimized and thoroughly simulated. The test chip is fabricated using a standard $0.18{\mu}m$ CMOS process. The active area of the chip is $1.6mm^2$. It operates for the signal bandwidth from 20Hz to 20kHz. The measured THD+N(total harmonic distortion plus noise) at the $32{\Omega}$ load terminal is less than 0.03% from a 3V power supply.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.11
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• pp.6-12
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• 2010

A sigma-delta modulator based class-D audio amplifier is presented. Parallel digital input is serialized to two-bit output by a fourth-order digital sigma-delta noise shaper. The output of the digital sigma-delta noise shaper is applied to a fourth-order analog sigma-delta modulator whose three-level output drives power switches. The pulse density modulated (PDM) output of the power switches is low-pass filtered by an LC-filter. The PDM output of the power switches is fed back to the input of the analog sigma-delta modulator. The first integrator of the analog sigma-delta modulator is a hybrid of continuous-time (CT) and switched-capacitor (SC) integrator. While the sampled input is applied to SC path, the continuous-time feedback signal is applied to CT path to suppress the noise of the PDM output. The class-D audio amplifier is fabricated in a standard $0.13-{\mu}m$ CMOS process and operates for the signal bandwidth from 100-Hz to 20-kHz. With 4-${\Omega}$ load, the maximum output power is 18.3-mW. The total harmonic distortion plus noise and dynamic range are 0.035-% and 80-dB, respectively. The modulator consumes 457-uW from 1.2-V power supply.

• Journal of IKEEE
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• v.22 no.3
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• pp.565-569
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• 2018

For the conventional power MOSFET (metal-oxide semiconductor field-effect transistor) device structure, there exists a tradeoff relationship between specific on-state resistance (Ron,sp) and breakdown voltage (BV). In order to overcome this tradeoff, a super-junction (SJ) trench MOSFET (TMOSFET) structure with uniform or non-uniform doping concentration, which decreases linearly in the vertical direction from the N drift region at the bottom to the channel at the top, for an optimal design is suggested in this paper. The on-state resistance of $0.96m{\Omega}-cm2$ at the SJ TMOSFET is much less than that at the conventional power MOSFET under the same breakdown voltage of 100V. A design methodology for the edge termination is proposed to achieve the same breakdown voltage and on-state resistance as the main body of the super-junction TMOSFET by using of the SILVACO TCAD 2D device simulator, Atlas.

• Journal of Educational Research in Mathematics
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• v.27 no.2
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• pp.171-189
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• 2017

By designing and applying the lesson helping to discover the power laws, we tried to investigate the characteristics on the class. To do this, we designed a discovery lesson on the power laws and applied to 54 8th grade students. As results, we could observe the overproduction of monotonous laws, tendency to vary the type of development and increase error to students without prior learning experience, and various errors. All participants failed to express the generalization of $a^m{\div}a^n$ and some participants expressed an incomplete generalization using variables partially for the base or power. We could also observe an error of limited generality or a representation error which did not use the equal sign or variables. In the survey of students, there were two contradictory positions to appeal to the enjoyment of the creation and to talk about the difficulty of creation. Based on such results, we discussed the pedagogical implications relating to the discovery of power laws.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.268-269
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• 2006

The estimation of applicability $SrTiO_3:Pr^{3+}$, Al to a class low-voltage flat-panel displays based on field emission effect, which have average value anode voltage $U_a=300V$ and current density $j=100\;mA/sm^2$ at duty 240, has given positive result. In the same time observably for the most effective sample in similar conditions of excitation high brightness - more than $500\;Kd/m^2$ and linear brightness dependences from current density and voltage allows to decrease greatly the power which consumed by the device.

• International Journal of Reliability and Applications
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• v.8 no.1
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• pp.27-39
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• 2007

Based on goodness of fit new testing procedures are derived for testing exponentiality against harmonic new renewal better than used in expectation (HNRBUE). For this aging properties, a nonparametric procedure (U-statistic) is proposed. The percentiles of this test statistic are tabulated for sample sizes n=5(1)30(10)50. The Pitman asymptotic efficiency (PAE) of the test is calculated and compared with, the (PAE) of the test for new renewal better than used (NRBU) class of life distribution [see Mahmoud et al (2003)]. The power of this test is also calculated for some commonly used life distributions in reliability. The right censored data case is also studied. Finally, real examples are given to elucidate the use of the proposed test statistic in the reliability analysis.

• Journal of IKEEE
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• v.7 no.1 s.12
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• pp.72-79
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• 2003

Classical designs of optical transimpedance preamplifier for p-i-n photodiode receiver circuits generally employ common source transimpedance input stages. In this paper, we explore the design of a class of current-mode optical transimpedance preamplifier based upon common gate input stages. A feature of current-mode optical transimpedance preamplifier is high gain and high bandwidth. The bandwidth of the transimpedance preamplifier can also be increased by the capacitive peaking technique. In this paper we included the development and application of a circuit analysis technique based on the minimum noise. We develop a general formulation of the technique, illustrate its use on a number of circuit examples, and apply it to the design and optimization of the low-noise transimpedance amplifier. Using the noise minimization method and the capacitive peaking technique we designed a transimpedance preamplifier with low noise, high-speed current-mode transimpedance preamplifier with a 1.57GHz bandwidth, and a 2.34K transimpedance gain, a 470nA input noise current. The proposed preamplifier consumes 16.84mW from a 3.3V power supply.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.755-758
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• 2002

This paper presents a second-generation CMOS current conveyor (CCII) consisting of a rail-to-rail complementary N- and P-channel differential input stage for the voltage input, a class AB push-pull stage for the current input, and current mirrors far the current outputs. The CCII was implemented using a double-poly triple-metal 0.6 ${\mu}$m n-well CMOS process, to confirm its operation experimentally. A prototype chip achieves a rail-to-rail swing ${\pm}$2.4 V under ${\pm}$2.5 V power supplies and shows the exact voltage and current following performances up to 100 MHz. Because of its high performances, the CCII proposed herein is quite useful for a building block of current-mode circuits. The applications of the proposed CCII to current-mode filters are also described.

• Communications for Statistical Applications and Methods
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• v.23 no.3
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• pp.215-230
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• 2016

The powers of some tests for independence hypothesis against positive (negative) quadrant dependence in generalized Farlie-Gumbel-Morgenstern distribution are compared graphically by simulation. Some of these tests are usual linear rank tests of independence. Two other possible rank tests of independence are locally most powerful rank test and a powerful nonparametric test based on the $Cram{\acute{e}}r-von$ Mises statistic. We also evaluate the empirical power of the class of distribution-free tests proposed by Kochar and Gupta (1987) based on the asymptotic distribution of a U-statistic and the test statistic proposed by $G{\ddot{u}}ven$ and Kotz (2008) in generalized Farlie-Gumbel-Morgenstern distribution. Tests of independence are also compared for sample sizes n = 20, 30, 50, empirically. Finally, we apply two examples to illustrate the results.