• ETRI Journal
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• v.34 no.2
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• pp.184-189
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• 2012

In this paper, we propose a novel approach to statistical model-based voice activity detection (VAD) that incorporates a second-order conditional maximum a posteriori (CMAP) criterion. As a technical improvement for the first-order CMAP criterion in [1], we consider both the current observation and the voice activity decision in the previous two frames to take full consideration of the interframe correlation of voice activity. This is clearly different from the previous approach [1] in that we employ the voice activity decisions in the second-order (previous two frames) CMAP, which has quadruple thresholds with an additional degree of freedom, rather than the first-order (previous single frame). Also, a soft-decision scheme is incorporated, resulting in time-varying thresholds for further performance improvement. Experimental results show that the proposed algorithm outperforms the conventional CMAP-based VAD technique under various experimental conditions.

• Geotechnical Engineering
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• v.13 no.1
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• pp.85-100
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• 1997

The heterogeneity of hydraulic conductivity of Metropolitan Waste Landfill is analized by using geostatistical methods and the contaminant transport analysis is performed by using heterogeneous hydraulic conductivity. The hydraulic conductivity data are obtained from laboratory pressurized permeability tests and the insitu, Slug test. Geostatistical methods used in this analysis are Ordinary Kriging and conditional simulation. It is concluded that the heterogeneities of hydraulic conductivity obtained from conditional simulation are greater than those from Ordinary Kriging analysis. The movement of the contaminant on the hydraulic conductivity with greater heterogeneity obtained from conditional simulation is faster than that observed in Ordinary Kriging analysis.

• Communications for Statistical Applications and Methods
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• v.22 no.4
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• pp.377-387
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• 2015

The area under the ROC curve can be represented by both Mann-Whitney and Wilcoxon rank sum statistics. Consider an ROC surface and manifold equal to three dimensions or more. This paper finds that the volume under the ROC surface (VUS) and the hypervolume under the ROC manifold (HUM) could be derived as functions of both conditional Mann-Whitney statistics and conditional Wilcoxon rank sum statistics. The nullhypothesis equal to three distribution functions or more are identical can be tested using VUS and HUM statistics based on the asymptotic large sample theory of Wilcoxon rank sum statistics. Illustrative examples with three and four random samples show that two approaches give the same VUS and $HUM^4$. The equivalence of several distribution functions is also tested with VUS and $HUM^4$ in terms of conditional Wilcoxon rank sum statistics.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.340-343
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• 2005

A realization for digital multimedia receiving system using Conditional Access System is presented in this paper. The key word for descrambling is make from smart card and Conditional Access System, a Stabilization is grow up in the method. It is possible to decoding that of average 15 fame/second of H.264 video format and that 24Khz${\sim}$48Khz audio sample rate using dual processor that of high performance DSP and RISC. This system is evaluated correct descrambling procedure in test stream added that signed user data.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.5
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• pp.985-996
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• 2019

This paper analyzes the source code of FIPS-OpenSSL cryptographic module approved as FIPS cryptographic module in USA and shows how the selftest requirements are implemented as software cryptographic library with respect to pre-operational test and conditional tests. Even though FIPS-OpenSSL follows FIPS 140-2 standard, lots of security requirements are similar between FIPS 140-2 and Korean cryptographic module validation standards. Therefore, analysis from this paper contributes to help Korean cryptographic module vendors develop correct and secure selftest functions on their own cryptographic modules, which results in reducing the test period.

• Proceedings of the Korean Statistical Society Conference
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• 2000.11a
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• pp.33-38
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• 2000

Krishnamoorphy and Raghavarao(1993) invented exact binomial and asymptotically normal test procedures for truthful answering in the repeated randomized response models under the assumption that two repeated response measures are independent. Under the same assumption, Lakshmi and Raghavarao(1992) suggested asymptotic chi-square test for respondents' truthful answering in the same models. In this article we detect the factors and the conditions with which two response variables might be independent, and find the condition for independence in the repeated randomized response models with considering untruthful answer. But, the condition of independence make the randomized model no meaning. Under the assumption of conditional independence between two response variables, we can apply the same logical statements on deriving the tests for truthful answering in the repeated randomized response models as in Krishnamoorphy and Raghavarao(1993).

• 한국연소학회:학술대회논문집
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• 2006.04a
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• pp.121-127
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• 2006

It has become inevitable to search for alternative fuels due to severe energy crisis these days. Use of alternative fuels, which are typically of lower quality, tends to increase environmental pollution, including formation of nitrogen oxides (NOx). In this paper performance of vacuum residue has been investigated experimentally as well as numerically in typical operating conditions of a furnace. Heat release reaction is modeled as sequential steps of devolatilization, simplified gas phase reaction and char oxidation as that for pulverized coal. Thermal and fuel NOx are predicted by conditional estimation of elementary reaction rates and are compared against measured experimental data. On the overall reasonable agreement is achieved for spatial distributions of major species, temperature and NOx for all test cases.

• Journal of Korea Water Resources Association
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• v.39 no.12 s.173
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• pp.997-1012
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• 2006

We have presented a nonparametric stochastic approach for the SOI(Southern Oscillation Index) series that used nonlinear methodology called Nonlinear AutoRegressive(NAR) based on conditional kernel density function and CAFPE(Corrected Asymptotic Final Prediction Error) lag selection. The fitted linear AR model represents heteroscedasticity, and besides, a BDS(Brock - Dechert - Sheinkman) statistics is rejected. Hence, we applied NAR model to the SOI series. We can identify the lags 1, 2 and 4 are appropriate one, and estimated conditional mean function. There is no autocorrelation of residuals in the Portmanteau Test. However, the null hypothesis of normality and no heteroscedasticity is rejected in the Jarque-Bera Test and ARCH-LM Test, respectively. Moreover, the lag selection for conditional standard deviation function with CAFPE provides lags 3, 8 and 9. As the results of conditional standard deviation analysis, all I.I.D assumptions of the residuals are accepted. Particularly, the BDS statistics is accepted at the 95% and 99% significance level. Finally, we split the SOI set into a sample for estimating themodel and a sample for out-of-sample prediction, that is, we conduct the one-step ahead forecasts for the last 97 values (15%). The NAR model shows a MSEP of 0.5464 that is 7% lower than those of the linear model. Hence, the relevance of the NAR model may be proved in these results, and the nonparametric NAR model is encouraging rather than a linear one to reflect the nonlinearity of SOI series.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.23 no.1
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• pp.134-145
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• 2024

The purpose of this study was to propose a framework for developing test scenarios for issuance of conditional driver's licenses. The framework was composed of five stages. Initially, we reviewed the literature on traffic crash characteristics in terms of accident frequency and severity regarding the main factors of crashes caused by older drivers. In the second stage, the characteristics of crashes attributed to non-elderly, early elderly, and late elderly drivers were analyzed using data obtained from the Traffic Accident Analysis System (TAAS), and crash types for elderly drivers were derived. In the third stage, black box videos of high-risk crash types were analyzed to derive crash stories that described the circumstances in which crashes occurred. In the fourth step, crash situations were classified by rating the types of crash stories derived to develop various scenarios. Step 5 involved creating a scenario by applying the PEGASUS 5-Layer format, which has recently been used to develop test scenarios for autonomous vehicles. The results of this study are expected to be used as a basis for developing driving ability evaluation scenarios for the issuance of conditional driver's licenses.

• Communications for Statistical Applications and Methods
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• v.8 no.2
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• pp.311-317
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• 2001

It is necessary to check the linearity of selected covariates in regression diagnostics. There are various graphical methods using residual plots such as partial residual plots, augmented partial residual plots and combining conditional expectation and residual plots. In this paper, we propose the modified pseudolikelihood ratio test statistics based on these residual plots to test linearity of selected covariate. These test statistics which measure the distance between the nonparametric and parametric models are derived as a ratio of quadratic forms. The approximate distribution of these statistics is calculated numerically by using three moments. The power comparison of these statistics is given.