• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.3
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• pp.206-213
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• 2022

This paper presents setting up a laboratory-scale testbed to estimate the aging of power MOSFET devices and integrated power modules by measuring its on-state voltage and current. Based on the aging mechanisms of the component inside the power module (e.g., bond-wire, solder layer, and semiconductor chip), a system to measure the on-state resistance of device-under-test (DUT) is designed and experimented: a full-bridge circuit applies current stress to DUT, and a temperature chamber controls the ambient temperature of DUT during the aging test. The on-state resistance of SiC MOSFET measured by the proposed testbed was increased by 2.5%-3% after 44-hour of the aging test.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.8
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• pp.808-820
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• 2014

In this paper, we fabricated two on-wafer type DUT(Device-Under-Test)s; a 10-dB attenuator and an amplifier using commercially available MMIC and we proposed the measurement method of the noise parameters for the two fabricated DUTs. Since the 10-dB attenuator DUT is a passive device, its noise parameters can be accurately determined when its S-parameters are measured. In the case of the amplifier DUT, its noise parameters are available in the datasheet. Hence, the measured noise parameters using the proposed method can be assessed by comparing with the known noise parameters. The noise parameter measurement method having been presented by the authors requires the S-parameters of the 8-port network used in the measurement and limited to coaxial type DUTs. When on-wafer probes are included in the 8-port network, the 8-port S-parameters requires the measurements with different kinds of connectors. In this paper, we obtained the 8-port S-parameters using the Smart-Cal function in the network analyzer. The measured noise parameters shows about ${\pm}0.2dB$ fluctuations for $NF_{min}$. Other noise parameters with the frequency change show good agreement with the expected results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.7
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• pp.491-499
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• 2018

The conventional calibration method for a noise figure analyzer is to use a noise source. This method is accompanied by a significant irregular ripple in the measurement results, because it does not consider the mismatch of the noise source and noise figure analyzer during calibration. A novel calibration method of the noise figure analyzer is proposed that considers the mismatch between the noise power and noise figure analyzer. A novel noise correlation matrix measurement technique using this method is also proposed. The method determines the noise correlation matrix and the gain of the uncorrected noise figure analyzer using uncorrected noise powers. Then, having determined the gain and noise correlation matrix, the effects of noise figure analyzers were corrected in the measurement results of the noise correlation matrix for the device under test (DUT). Through the proposed method, the measured noise parameters of a DUT showed the same degree of irregular ripples as the result of using the relative noise ratio.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.27 no.4
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• pp.217-227
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• 2015

In this study, two-dimensional physical experiment was carried out to examine the applicability of the three formulas(Takahashi and Shimosako, 1994; Tabet-Aoul and Lambert, 2003; Li, 2007), which were proposed to calculate the wave forces acting on perforated caisson breakwaters. In order to quantitatively compare the measured with the estimated values based on the wave formulas, the refined index of agreement and the coefficient of determination were calculated, by which the degree of agreement was evaluated. Among the three wave formulas, DUT formula (Li, 2007) showed the smallest deviation from the measured forces, whereas Takahashi formula (Takahashi and Shimosako, 1994) showed the largest deviation. Meanwhile, comparison of the magnitude of the measured wave forces with those from the three formulas revealed that DUT formula slightly underestimate, while the others overestimate the measured forces.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.7
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• pp.3268-3283
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• 2018

With the advent of the Information Age, the source identification of digital images, as a part of digital image forensics, has attracted increasing attention. Therefore, an effective technique to identify the source of digital images is urgently needed at this stage. In this paper, first, we study and implement some previous work on image source identification based on sensor pattern noise, such as the Lukas method, principal component analysis method and the random subspace method. Second, to extract a purer sensor pattern noise, we propose a sample selection method to improve the random subspace method. By analyzing the image texture feature, we select a patch with less complexity to extract more reliable sensor pattern noise, which improves the accuracy of identification. Finally, experiment results reveal that the proposed sample selection method can extract a purer sensor pattern noise, which further improves the accuracy of image source identification. At the same time, this approach is less complicated than the deep learning models and is close to the most advanced performance.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.1
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• pp.47-52
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• 2002

It was virtually declared that measurement science must abandon the error analysis of measurement when ISO had published "Guide to Expression of uncertainty in Measurement" International inclination of measurement field in order to guarantee the traceability and confidence of measurement results discards the error concept and instead analyzes the measurement uncertainty. In this paper we establish a mathematical model of measurement and analyze all uncertainty factors as possible as for yielding the measurement uncertainty in the course of the calibration of RF multimeter using Transfer Standard, Thermal Voltage Converter We produce the expanded uncertainty by analyzing cable effects, correlation of thermocoupler and DC meter, DC source, RF source, attenuator, reflection coefficients and DUT.s and DUT.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.3
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• pp.259-262
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• 2013

Multi-site testing is considered as a solution to reduce test costs. This paper presents a new channel sharing architecture that enables I/O pins to share automatic test equipment (ATE) channels using simple circuitry such as tri-state buffers, AND gates, and multiple-input signature registers (MISR). The main advantage of the proposed architecture is that it is implemented on probe cards and does not require any additional circuitry on a target device under test (DUT). In addition, the proposed architecture can perform DC parametric testing of the DUT such as leakage testing, even if the different DUTs share the same ATE channels. The simulation results show that the proposed architecture is very efficient and is applicable to both wafer testing and package testing.

• Journal of electromagnetic engineering and science
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• v.15 no.4
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• pp.258-265
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• 2015

A de-embedding method for multiport networks, especially for coupled odd interconnection lines, is presented in this paper. This method does not require a conversion from S-parameters to T-parameters, which is widely used in the de-embedding technique of multiport networks based on cascaded simple two-port relations, whereas here, we apply an operation to the S-matrix to generate all the uncoupled and coupled coefficients. The derivation of the method is based on the relations of incident and reflected waves between the input of the entire network and the input of the intrinsic device under test (DUT). The characteristics of the intrinsic DUT are eventually achieved and expressed as a function of the S-parameters of the whole network, which are easily obtained. The derived coefficients constitute ABCD-parameters for a convenient implementation of the method into cascaded multiport networks. A validation was performed based on a spice-like circuit simulator, and this verified the proposed method for both uncoupled and coupled cases.

• Journal of the Korean Home Economics Association
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• v.36 no.9
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• pp.49-62
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• 1998

This paper investigates the parenting stress of fathers who have preschooler. At first, a causal model constructed, including the parenting stress as a dependent variable and the psychological characteristics of paternal self-esteem and parenting efficacy as parameters. Based on the change of parenting stress, self-esteem and parenting efficacy according to various pertinent to fathers, the causal effect of various variables effecting on the paternal parenting stress is analyzed. The SPSS PC program was used for the statistical analysis, where fully exploited were frequencies, percentages, means, standard deviations, Cronbach α, one-way analysis(ANOVA), path analysis. The results can be summarized into 3 parts, in conclusion: 1) The younger a father is, the higher paternal self-esteem becomes. Paternal self-esteem trend was there, for a father who is a member of large family, and for a father whose education level is high, and for a father whose occupation is professional. Regarding parenting sense of competence, a father shows confidence when he has more income, more educated and less children. 2) The variable analysis effecting on the parenting stress dut to the paternal environment shows that a father feels more stress when his income is less and his spouse is working. The sub-factor analysis on the parenting stress shows that 'typical stress dut to the parenting' increases when his income is less and his spouse is working, and 'pressures pertaning to the parental role and distress' increases for a father with less income, working spouse, less educated and non-professional job. Further 'guilty to the parenting by others' shows higher for a father with less income and a working spouse. 3) The path analysis, which were performed to check the causality of the parenting stress dut to various variables, shows that the self-esteem and the parenting efficacy are significant factors directly effecting on the paternal parenting stress, and the job-satisfaction and marriage-satisfaction are significantly effecting on the parenting stress both directly and indirectly.

• Journal of Korea Society of Industrial Information Systems
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• v.21 no.1
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• pp.61-70
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• 2016

This paper describes a new PMU(parametric measurement unit) design technique for automatic test equipment(ATE). Only one DDA(differential difference amplifier) is used to force the test signals to DUT(device under test), while conventional design uses two or more amplifiers to force test signals. Since the proposed technique does not need extra amplifiers in feedback path, the proposed PMU inherently guarantees stable operation. Moreover, to measure the response signals from DUT, proposed technique also adopted only one DDA amplifier as an IA(instrument amplifier), while conventional IA uses 3 amplifiers and several resistors. The DDA adopted two rail-to-rail differential input stages to handle full-range differential signals. Gain enhancement technique is used in folded-cascode type DDA to get open loop gain of 100 dB. Proposed PMU design enables accurate and stable operation with smaller hardware and lower power consumption. This PMU is implemented with 0.18 um CMOS process and supply voltage is 1.8 V. Input ranges for each force mode are 0.25~1.55 V at voltage force and 0.9~0.935 V at current force mode.