• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.63 no.2
• /
• pp.291-296
• /
• 2014

Most of the statistical signal analysis processed in the time domain and the frequency domain are based on the assumption that the signal is weakly stationary(wide sense stationary). Therefore, it is necessary to know whether the surface EMG signals processed in the statistical basis satisfy the condition of weak stationarity. The purpose of this study is to analyze the accuracy of the Run-test, modified Run-test, RA(reverse arrangement)-test, and modified RA-test for assessing surface EMG signal stationarity. Six stationary and three non-stationary signals were simulated by using sine wave, AR(autoregressive) modeling, and real surface EMG. The simulated signals were tested for stationarity using nine different methods of Run-test and RA-test. The results showed that the modified Run-test method2 (mRT2) classified exactly the surface EMG signals by stationarity with 100% accuracy. This finding indicates that the mRT2 may be the best way for assessing stationarity in surface EMG signals.

• Journal of the Korea Convergence Society
• /
• v.10 no.4
• /
• pp.195-201
• /
• 2019

The purpose of this study was to propose an effective field test for assessing the cardiovascular endurance of soccer players by comparing the shuttle run test and the Yo-Yo intermittent recovery test (Yo-Yo test), which are representative of the aerobic exercise performance test, with the VO2max and other sprint tests. The shuttle run test requires the subject to run continuously without a break interval, while the Yo-Yo test has a break interval, so that they run with the recovery period. Therefore, the Yo-Yo test can be used as an effective field test for evaluating the cardiopulmonary function considering the characteristics of the soccer players of intermittent training.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.22 no.4
• /
• pp.145-151
• /
• 2014

Modern vehicle has a lot of ECU(Electronic Control Unit) products to control many parts such as engine, transmission, brake, body and so on. ECU quality is one of important factors related to vehicle quality and driver's safety. Based on Bath-tub curve which presents failure rate during product lifetime, we designed and applied Accelerated Run-in Test into manufacturing line by simulating stress amount to ECU and developing the required software and efficient test equipment for mass production. This test makes ECU products stressed through electrical and thermal stresses under excessive driving condition, which induce potential initial failure of components in the ECU during production. The outcome until these days proved that Acceleration Run-in Test have reduced initial failure rates and increased quality of ECU products in the field outstandingly.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.63 no.8
• /
• pp.1128-1133
• /
• 2014

Most of the statistical signal analysis processed in the time domain and the frequency domain are based on the assumption that the signal is weakly stationary(wide sense stationary). Therefore, it is necessary to know whether the surface EMG signals processed in the statistical basis satisfy the condition of the weak stationarity. The purpose of this study is to find optimal segment length of surface EMG signal for assessing stationarity with the modified Run-test and RA-test. Ten stationary surface EMG signals were simulated by AR(autoregressive) modeling, and ten real surface EMG signals were recorded from biceps brachii muscle and then modified to have non-stationary structures. In condition of varying segment length from 20ms to 100ms, stationarity of the signals was tested by using six different methods of modified Run-test and RA-test. The results indicate that the optimal segment length for the surface EMG is 30ms~35ms, and the best way for assessing surface EMG signal stationarity is the modified Run-test (Run2) method using this optimal length.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2003.11a
• /
• pp.718-723
• /
• 2003

The number of jet aircraft is increasing. The aircraft noise making people near airports nervous have become a serious social problem. The aircraft noise can be classified into two groups; noise being generated at take-off or landing and noise form run-up test on the ground. In this paper, we consider the aircraft noise from run-up test on the pound and we suggest the noise suppression system.

• Speech Sciences
• /
• v.10 no.1
• /
• pp.95-105
• /
• 2003

This paper describes a new parameter for voice activity detection which serves as a front-end part for automatic speech recognition systems. The new parameter called run-ratio is derived from the runs test statistic which is used in the statistical test for randomness of a given sequence. The run-ratio parameter has the property that the values of the parameter for the random sequence are about 1. To apply the run-ratio parameter into the voice activity detection method, it is assumed that the samples of an inputted audio signal should be converted to binary sequences of positive and negative values. Then, the silence region in the audio signal can be regarded as random sequences so that their values of the run-ratio would be about 1. The run-ratio for the voiced region has far lower values than 1 and for fricative sounds higher values than 1. Therefore, the parameter can discriminate speech signals from the background sounds by using the newly derived run-ratio parameter. The proposed voice activity detector outperformed the conventional energy-based detector in the sense of error mean and variance, small deviation from true speech boundaries, and low chance of missing real utterances

• International Commerce and Information Review
• /
• v.8 no.2
• /
• pp.299-312
• /
• 2006

This study examines the relations among wage differentials, trade, and productivity in Korea, using the methodology of Granger causality and vector error correction modelling. Cointegration test results over the 1975-2004 period indicate that all the test variables are cointegrated. Therefore, wage differentials, trade, and productivity are all related in the long run. We found some evidence on long-run relationship, while there is no short-run relationship between three test variables. First, trade and wage differentials have positively and bi-directionally Granger causality in the long-run. Second, productivity Granger causes negatively wage differentials in the long-run. Finally, productivity Granger causes positively trade in the long-run. These results explain partially the current theoretical predictions for wage inequality as well as supports the productivity-led growth hypothesis in the Korean economy.

• The Journal of Asian Finance, Economics and Business
• /
• v.8 no.3
• /
• pp.139-154
• /
• 2021

This study's impetus is to explore fresh evidence to answer the question, i.e., whether remittances asymmetrically influence financial development in Bangladesh from 1975 to 2019. The study employs several tests, i.e., nonlinear unit root test, Autoregressive Distributed Lagged (ARDL), NARDL, and asymmetric causality test for establishing the pattern of association. Nonlinear unit root tests confirm that variables follow a nonlinear system of being stationary after the first difference. nonlinearity among variables is investigated by performing the BDS test and nonlinear OLS. Directional causality is investigated through both linear and nonlinear effects of remittance inflows by following the non-granger casualty test. The test statistics of Fpass and tBDM showed the Long-run cointegration in the empirical model and positive effect running from remittances inflow to financial development both in the long-run and short-run. Furthermore, the results of a standard Wald test divulge the presence of long-run and short-run asymmetry. Asymmetry causality test established unidirectional causality due to positive and negative shocks in remittances inflows to Bank-based financial development and feedback hypothesis hold for explaining causality between positive and negative shocks in remittance inflows and Stock-based financial development.

• Water for future
• /
• v.18 no.4
• /
• pp.317-325
• /
• 1985

In the analysis, monthly streamflow records atthe gauging station in Nakdong, Han and Geum river were used. Also, the fitness of monthly streamflow to Gamma and Long-normal distribution was tested by Kolomogorv-Smirnov test. The results obtained in this study can be summarized as follws (1) The fitness of monthly streamflow to two-parameter Gamma distribution was tested by Kolomorov-Smirnov test, which fits well to this Gamma distribution (2) The Run-length and Run-sum were simulated by the Gamma model. In this result, run-length and Run-sum of monthly streamflow were fit for Gamma model (3) The mean decreases (increases) the expected surplus (deficit) Run-Sum of the monthly streamflow. The higher the truncation level of negative Run-length and Run-sum the larger is the effect of mean.

• Journal of Electrical Engineering and Technology
• /
• v.8 no.1
• /
• pp.156-162
• /
• 2013

This paper measures the hot spot temperatures in a single-phase, 154 kV, 15/20 MVA power transformer filled with natural ester fluid using optical fiber sensors and compares them with those calculated by conventional heat run tests. A total of 14 optical fiber sensors were installed on the high-voltage and low-voltage windings to measure the hot spot temperatures. In addition, three thermocouples were installed in the transformer to measure the temperature distribution during the heat run tests. In the low-voltage winding, the hot spot temperature was $108.4^{\circ}C$, calculated by the conventional heat run test. However, the hot spot temperature measured using the optical fiber sensor was $129.4^{\circ}C$ between turns 2 and 3 on the upper side of the low-voltage winding. Therefore, the hot spot temperature of the low-voltage winding measured using the optical fiber sensor was $21.0^{\circ}C$ higher than that calculated by the conventional heat run test.