• International Journal of Railway
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• v.4 no.1
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• pp.12-18
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• 2011

The ATS system is used to provide wayside signaling. Currently, the oscillation frequency is set at 78[kHz] in the normal state. As the on-board receiver crosses over the wayside transmitter, the oscillation frequency is changed by capacitors of the wayside transmitter in a manner dependent on the train speed. As the oscillation frequency is changed, the waveform is modified in the wayside transmitter as well as in the on-board receiver. When there are other signal systems such as a ATO system present near the wayside transmitter, frequency interference occurs. This phenomenon arises since other signals or communication frequencies present will be included in the waveform. Trains often stop due to these other frequencies included in the waveform. In this paper, a model of the interaction between the wayside transmitter and on-board receiver is suggested and frequency response in the wayside transmitter and on-board receiver in the presence of the other signals are estimated by the coupling coefficient. Also, the coupling coefficients are estimated, and the optimal value is proposed.

• International journal of advanced smart convergence
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• v.9 no.4
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• pp.42-51
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• 2020

In this paper, the authors propose the pseudo complex correlation coefficient (PCCC) of the two complex random variables (RV), because the four real correlation coefficients (RCC) of the corresponding four real RVs cannot be obtained only from the complex correlation coefficient (CCC) of given two complex RV. Such observation is motivated by the general statement; "The complex jointly-Gaussian random M-vector cannot be completely described by the complex covariance matrix, even though the real Gaussian random 2M-vector can be completely descried by the real covariance matrix. Therefore, in order to describe completely the complex jointly-Gaussian random M-vector, we need an additional matrix, namely the complex pseudo-covariance matrix, along with the complex covariance matrix." Then, we apply PCCC to correlated information sources (CIS) for non-orthogonal multiple access (NOMA) in 5G system, and investigate impact of the proposed PCCC on the achievable data rate of the stronger channel user in the conventional successive interference cancellation (SIC) NOMA with CIS. It is shown that for the given same CCC, the achievable data rates with the different PCCC are different, because the corresponding RCC are different. We also show that as the absolute value of the same CCC increases, the impact of the different PCCC becomes more significant.

• Current Optics and Photonics
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• v.7 no.5
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• pp.529-536
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• 2023

The Morlet wavelet transform method is proposed to analyze a single interferogram with spatial carrier frequency that is captured by an optical interferometer. The method can retain low frequency components that contain the phase information of a measured optical surface, and remove high frequency disturbances by wavelet decomposition and reconstruction. The key to retrieving the phases from the low-frequency wavelet components is to extract wavelet ridges by calculating the maximum value of the wavelet transform amplitude. Afterwards, the wrapped phases can be accurately solved by multiple iterative calculations on wavelet ridges. Finally, we can reconstruct the wave-front of the measured optical element by applying two-dimensional discrete cosine transform to those wrapped phases. Morlet wavelet transform does not need to remove the spatial carrier frequency components manually in the processing of interferogram analysis, but the step is necessary in the Fourier transform algorithm. So, the Morlet wavelet simplifies the process of the analysis of interference fringe patterns compared to Fourier transform. Consequently, wavelet transform is more suitable for automated programming analysis of interference fringes and avoiding the introduction of additional errors compared with Fourier transform.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.6
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• pp.636-642
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• 2019

In this paper, we analyzed BER (Bit Error Rate) communication performance according to the detection order of MMSE (Minimum Mean Square Error) based soft decision interference cancellation. As the detection order method, antenna index order method, absolute value magnitude order method of channel elements, absolute value sum order method of channel elements, and SNR (Signal Noise Ratio) order method are proposed. BER performance for the scheme was measured and analyzed. As a simulation environment, 16-QAM (Quadrature Amplitude Modulation) modulation is used in an uncoded environment of an M×M multiple-input multiple-output system, and an independent Rayleigh attenuation channel is considered. The simulation results show that the performance gain is about 1.5dB when the SNR-based detection order method is M=4, and the performance gain is about 3.5dB when M=8 and about 3.5dB when M=16. The more BER performance was confirmed, the more the detection order method of the received signal prevented the interference and error spreading occurring in the detection process.

• Cross-Cultural Studies
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• v.29
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• pp.153-176
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• 2012

This study focused on concretely how minority group's attitude accepting han-zu's culture changes. In the past, minority group's culture and han-zu's culture were acculturated spontaneously, not forcibly. But as the people's republic of china was founded and control of chinese government was intensified, control and interference of minority group area became aggressive, and acculturation became compulsory. However, after chinese economic reform, by economic affluence and modernization and urbanization according to economic affluence, acculturation of minority group's culture and han-zu's culture is changing from forced acculturation to spontaneous acculturation. Still there are some areas where mutual friction lasts because of forced acculturation. But except some areas the stream is changing rapidly to spontaneous acculturation. In the text, this study investigated process and present state of acculturation focused on hui-zu that implemented aggressive acceptance of han-zu's culture relatively early. Then this study investigated yi-zu society and cultural change focused on their spontaneous acculturation. In the modern society setting a high value on convenience and personal happiness rather than ideology and value, value of race becomes less attractive to young people of minority group who know modern civilization and convenience of city. In this respect, maybe hui-zu society is future of yi-zu society and minority group society.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.9
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• pp.2927-2941
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• 2022

The primary task of machine fault diagnosis is to judge whether the current state is normal or damaged, so it is a typical binary classification problem with mutual exclusion. Mutually exclusive events and out-of-domain detection have one thing in common: there are two types of data and no intersection. We proposed a fusion model method to improve the accuracy of machine fault diagnosis, which is based on the mutual exclusivity of events and the commonality of out-of-distribution detection, and finally generalized to all binary classification problems. It is reported that the performance of a convolutional neural network (CNN) will decrease as the recognition type increases, so the variational auto-encoder (VAE) is used as the primary model. Two VAE models are used to train the machine's normal and fault sound data. Two reconstruction probabilities will be obtained during the test. The smaller value is transformed into a correction value of another value according to the mutually exclusive characteristics. Finally, the classification result is obtained according to the fusion algorithm. Filtering normal data features from fault data features is proposed, which shields the interference and makes the fault features more prominent. We confirm that good performance improvements have been achieved in the machine fault detection data set, and the results are better than most mainstream models.

• Korean Journal of Clinical Laboratory Science
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• v.55 no.1
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• pp.45-51
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• 2023

Canine parvovirus type 2 (CPV-2) and canine coronavirus (CCoV) are major pathogens that can induce gastroenteritis in dogs. They are highly contagious and have a high morbidity rate. There are no specific treatments available for them to date. Therefore, rapid and accurate diagnosis becomes essential. The rapid diagnostic test (RDT) for animals can be used widely in the field because it is fast and easy to use for diagnosis. Thus, this study aimed to clinically evaluate and confirm the clinical utility of CPV-2/CCoV RDT. The parameters evaluated included the limit of detection (LoD), cross-reactivity, interference, sensitivity, specificity, negative likelihood ratio (NLR), and kappa value. The results revealed that the LoD values for CPV-2 and CCoV were 9.7×10 50% tissue culture infectious dose (TCID₅₀)/mL and 2.5×10² TCID₅₀/mL, respectively. There was no cross-reactivity with nine pathogens or interference by interfering materials. The RDT showed a sensitivity of 90.0%, a specificity of 100.0%, NLR of 0.1, and a kappa value of 0.90 for diagnosing both viruses. In conclusion, CPV-2/CCoV RDT is useful as a screening test because of its high sensitivity, specificity, kappa value, and low NLR.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.6
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• pp.2381-2391
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• 2013

In general, ground's thermal properties, types of heat exchanger, operational method, thermal interference between piles can be considered as key factors which affect the thermal performance of energy pile. This study focused on the effect of these factors on the performance by a numerical model reflecting a real ground condition. Depending on the degree of saturation of ground, pile's heat transfer rate showed a maximum difference of three times, and the thermal resistance of pile made a maximum difference of 8.7%. As for the type of heat exchanger effects on thermal performance, thermal efficiency of 3U type energy pile had a higher value than those of W and U types. The periodic operation (8 hours operation, 16 hours pause) can preserve about 20% of heat efficiency compared to continuous operation, and hence it has an advantage of preventing the thermal accumulation phenomenon. Thermal interference effect in group piles may vary depending on the ground condition because the extent decreases as the ground condition varies from saturated to dry. The optimal separation distance that maintains the decreasing rate of heat efficiency less than 1% was suggested as 3.2D in U type, 3.6D in W type, and 3.7D in 3U type in a general ground condition.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.4
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• pp.539-549
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• 1999

In this paper, the bit error rare (BER) performance of DS/CDMA DQPSK communication system in the presence of multi access interference, impulsive noise and Nakagami fading is investigated. The DS/CDMA DQPSK communication system adopts Maximum Ratio Combining (MRC) diversity reception and error correcting BCH code technique to enhance system performance. Using the derived error probability equation, the error rate performance of DS/CDMA DQPSK communication system has been evaluated and shown in figures to discuss as a function of impulsive index(A), Gaussian noise to impulsive noise power ratio($\Gamma$'), multi access interference(Κ), Nakagami fading parameter(m), the number of diversity branch (Ｌ), the number of error correction symbol (t), PN code sequence length(N) and $E_b/N_0$. The error performance of DS/CDMA-MDPSK signals improve by adopting MRC diversity and BCH(15,7) coding technique in the environment of impulsive noise plus Nagakami fading. From the results, we known that proposed system is affected by multi access interference, impulsive noise and Nakagami fading in radio communication system environment. Also, BER performance of DS/CDMA DQPSK communication system cam be improved increasing either the power of desired signal or the value of Gaussian noise to impulsive noise power ratio. And BCH(15,7) code technique is more effective to restrain the affection of multi access, interference, impulsive noise and Nakagami fading in DS/CDMA DQPSK communication system than MRC diversity reception technique.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.4
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• pp.427-438
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• 1998

The bit error rate(BER) performance of Trellis Coded QPSK signal in the presence of cochannel interference (CCI) and Rician fading is investigated. The trellis coded QPSK system adopts Maximum Ratio Combining (MRC) diversity reception and Reed-Solomon code to enhance system performance. Using the derived error probability equation, the error performance of trellis coded QPSK system has been evaluated and shown in figures to discuss as a function of signal power to noise power ratio (SNR), signal power to interference power ratio(SIR), direct to indirect signal power ratio ($K_R$), the number of diversity branch (M), the frame length of Reed-Solomon code (n), the number of error correction symbol (t), and the number of state of trellis encoder. From the results, we know that proposed system is affected by cochannel interference and fading in microcell environment. Also, BER performance of Trellis Coded QPSK system can be improved as increasing either the power of desired signal or the value of SIR. And the BER floor in microcellular system is caused by the cochannel interference and it occurs at high BER when SIR is low. And Reed-Solomon code (n=15, t=2) is more effective to restrain the affection of CCI and fading than MRC diversity reception (M=2).