• Journal of Life Science
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• v.10 no.2
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• pp.177-181
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• 2000

This study was conducted to estimate the genetic parameters such as combining ability, heritabilities and correlation coefficients forsome agronomic characters by 6$\times$6 dialled crosses of barley. The results obtained were summarized as follows. Mean squares of general combining ability(GCA) and specific combining ability(SCA) were significant for all characters observed. Mean squares of general combining ability for all characters were expressed as higher values than those of specific combining ability. Jecheon #5 showed the high general combining ability effects for culm length, and Waegwanpimack #1 showed the highest general combining ability effects for tiller number. Cygne also showed the high general combining ability effects for spike length and 1,000 grains weight. Furthermore, Plumage was expressed with the highest general combining ability effects for spike length and 1,000 grains weight. Furthermore, Plumage was expressed with the highest general combining ability effects for number of grains per spike. In specific combining ability effects, Samdugjeonbug # 45$\times$Plumage showed the high value for culm length, and Suwon #6 $\times$Waegwanpimack #1$\times$ was expressed with the highest specific combining ability effects for tiller number. Jecheon #5$\times$Plumage also showed the high specific combining ability effects for spike length and number of grains per spike. Suwon #6$\times$Cygne showed the high specific combining ability effects for 1,000 grains weight. The heritabilities of spike length an number of grains per spike were over 90%. In correlation coefficients among characters, relationships between culm length and tiller number, culm length and spike length, culm length and 1,000 grains weight, and spike length and 1,000 grains weight showed highly positively correlation.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.10
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• pp.168-174
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• 2015

In this paper, we analyze the performance of cooperative communication techniques on an underwater channel. By analyzing the BER performance of cooperative transmission protocol and combining types ERC, FRC, SNRC and ESNRC on underwater channel, through the result, we can choose an a proper cooperative technique for an underwater channel. The analysis of BER performance is achieved by a computer simulation.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.10
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• pp.1-13
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• 2022

This paper empirically explores the predicting ability of the newly proposed smooth transition (ST) time-varying combining forecast methods. The proposed method allows the "weight" of combining forecasts to change gradually over time through its unique feature of transition variables. Stock market returns from 7 countries were applied to Ad Hoc models, the well-known Generalized Autoregressive Conditional Heteroskedasticity (GARCH) family models, and the Smooth Transition Exponential Smoothing (STES) models. Of the individual models, GJRGARCH and STES-E&AE emerged as the best models and thereby were chosen for constructing the combined forecast models where a total of nine ST combining methods were developed. The robustness of the ST combining forecasts is also validated by the Diebold-Mariano (DM) test. The post-sample forecasting performance shows that ST combining forecast methods outperformed all the individual models and fixed weight combining models. This study contributes in two ways: 1) the ST combining methods statistically outperformed all the individual forecast methods and the existing traditional combining methods using simple averaging and Bates & Granger method. 2) trading volume as a transition variable in ST methods was superior to other individual models as well as the ST models with single sign or size of past shocks as transition variables.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.11
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• pp.19-23
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• 2010

In this paper, we propose a combining scheme for partial IR based hybrid ARQ in MIMO systems. The proposed combining scheme is a symbol-level combining scheme for repeatedly transmitted systematic symbols in partial IR based hybrid ARQ. In this paper, it is shown that the proposed combining scheme can also enhance the detection performance of the parity symbols that are newly transmitted in each retransmission. Simulation results show that the proposed combining scheme significantly improves the performance of the partial IR based hybrid ARQ compared to the cases of the conventional bit-level combining scheme, especially with the ZF detection.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.4
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• pp.442-450
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• 2008

In this paper, the phase diverisity in a direct-conversion receiver for a UHF RFID reader is analyzed and the optimal I/Q signal combining methods is presented with respect to tag modulation. At first, fading characteristics of a single channel receiver is shown to prove the importance of phase diversity due to the phase relationship between the backscattered signal and the local oscillator. And the optimal signal combining methods are presented in order to overcome the signal power reduction due to phase diversity. In case of ASK, the power combining method is presented for the optimal I/Q combining. And the arctangent and principal component combining methods using covariance matrix of I and Q channels are presented for the optimal I/Q combining in case of PSK. In order to analyze the performance of suggested methods, the selection diversity and the optimal combining methods are compared. According to analysis and simulation results, the optimal combining methods have a maximum 3 dB SNR enhancement than selection diversity.

• Journal of Advanced Navigation Technology
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• v.17 no.3
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• pp.298-305
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• 2013

In this paper, we propose simple combining schemes for sensing ATSC digital television signals with spectral correlation density (SCD). The detection algorithms exploiting the cyclostationarity exhibited by the pilot of ATSC digital television signals usually use the SCD value at a given particular frequency. However, we found that non-zero SCDs are found to be distributed over a certain range of frequencies in multipath fading environment. To utilize a set of non-zero SCD values computed in the vicinity of the pilot location, we formulate a class of combining methods in analogy with the maximal ratio combining, the square law combining and the equal gain combining. We show that the proposed simple combining schemes improve the detection performance by 0.5~1.0dB under multipath fading environments.

• Communications for Statistical Applications and Methods
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• v.22 no.6
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• pp.639-646
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• 2015

We propose simultaneous tests for mean and variance under the normality assumption. After formulating the null hypothesis and its alternative, we construct test statistics based on the individual p-values for the partial tests with combining functions and derive the null distributions for the combining functions. We then illustrate our procedure with industrial data and compare the efficiency among the combining functions with individual partial ones by obtaining empirical powers through a simulation study. A discussion then follows on the intersection-union test with a combining function and simultaneous confidence region as a simultaneous inference; in addition, we discuss weighted functions and applications to the statistical quality control. Finally we comment on nonparametric simultaneous tests.

• Journal of Communications and Networks
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• v.12 no.6
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• pp.616-623
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• 2010

In this paper, exact closed-form expressions for outage probability and bit error probability (BEP) are presented for multi-hop decode-and-forward (DF) relaying schemes in conjunction with cooperative diversity, in which selection combining technique is employed at each node. We have shown that the proposed protocol offers remarkable diversity advantage over direct transmission as well as the conventional DF relaying schemes with the same combining technique. We then investigate the system performance when different diversity schemes are employed. It has been observed that the system performance loss due to selection combining relative to maximal ratio combining is not significant. Simulations are performed to confirm our theoretical analysis.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.4
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• pp.47-52
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• 1998

As to power combining system, it is very important to achieve a high combining efficiency in order to minimize theamount of prime power needed and hence the cooling requirements, all of which translate into reduced cost. The combining efficiency is degraded in practice by variation in the amplitude and phase of the signals to be combined. In this paper, the new power combining newtork is proposed and realized which has the automatic gain and phase control system. This control system makes amplituede and phase variation of its all path equal. When the amplitude and phase variations are within 0~5dB and .+-.50.deg., the results show that high combining efficiency is maintained.

• Journal of Communications and Networks
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• v.9 no.1
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• pp.67-74
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• 2007

The performance of dual diversity receivers operating over correlated Ricean fading channels is analyzed. Using a previously derived rapidly converging infinite series representation for the bivariate Ricean probability density function, analytical expressions for the statistics of dual-branch selection combining, maximal-ratio combining, and equal-gain combining output signal-to-noise ratio (SNR) are derived. These expressions are employed to obtain novel analytical formulae for the average output SNR, amount of fading, average bit error probability, and outage probability. The proposed mathematical analysis is used to study various novel performance evaluation results with parameters of interest the fading severity, average input SNRs, and the correlation coefficient. The series convergence rate is also examined verifying the fast convergence of the analytical expressions. The accuracy of most of the theoretical performance evaluation results are validated by means of computer simulations.