• Journal of IKEEE
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• v.22 no.3
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• pp.638-644
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• 2018

In this paper, we develop a measurement system that uses 3D Scintillator and NaI(TI) Detector to 3-dimensionally identify the location of multiple radiation sources in moving vehicle loads. The radiation measurement system consists of radiation measurement (plastic scintillator), 2-channel Pulse Counter Board, nuclide analysis (NaI(TI) detector) and 1 channel MCA Board. The source locator algorithm calculates the coordinate value of the ratio of the CPS value($1/r^2$) of the source according to the angle(${\theta}$) in inverse proportion to the square of the distance(X, Y) through the SVM classification. The coordinate values are input every predetermined period of the spectrum, and after analyzing the spectrum per unit cycle, the position of the nuclide at the time is calculated by determining whether or not the nuclide is present in the remaining part except for the background area. As a result of the position discrimination test, the error within the international standard of ${\pm}1m$ was shown. Thus, the utility of the proposed system has been demonstrated.

• Korean journal of communication and information
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• v.66
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• pp.28-58
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• 2014

South Korean broadcasting industry has been under a significant level of structural change since the permission of new general programming channels in the end of 2010. One of the most characteristic features of the change may be the exodus of core manpower from the in-house productions of major terrestrial broadcasters which have been maintaining their dominant power over broadcasting content market based on their systems of tight vertical integration. This paper sheds light on the presence of a purposeful 'mechanism design' that aims to the expansion of market logics in South Korean broadcasting sector by promoting commercial media conglomerates, and analyses how this external design has been actualized while being interlocked with various internal factors of the broadcasting industry. This paper shows that on the backdrop of the mechanism design, some of new media conglomerates has successfully provided various incentives in contrast with those disincentive of terrestrial broadcasters, which in turn, has facilitated the exodus of elite producers. This paper, however, raises a set of questions about whether this relocation process of creativity led by commercial media conglomerates would, in the long term, guarantee more opportunities and potentials for the producers, as promised. As part of conclusion, inherent problems of present mechanism design are highlighted.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.3
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• pp.99-105
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• 2015

This paper deals with the mMMA (modified MMA) which possible to improving the convergence speed that employing the serial connecting form of two stage digital filter instead of signal filter of MMA adaptive equalizer without applying the variable step size for compensates the intersymbol interference by channel distortion in the nonconstant modulus signal. The adaptive equalizer can be implemented by signal digital filter using the finite order tap delay line. In this paper, the equalizer is implemented by the two stage serial form and the filter coefficient are updated by the error signal using the same algorithm of MMA in each stage. The fast convergence speed is determined in the first stage, and the residual isi left at the output of first stage output is minimized in the second stage filter. The same digital filter length was considered in single stage and two stage system and the performance of these systems were compared. The performance index includes the output signal constellation, the residual isi and maximum distortion, MSE that is measure of the convergence characteristics, the SER. As a result of computer simulation, mMMA that has a FIR structure of two stage, has more good performance in every performance index except the constellation diagram due to equalization noise and improves the convergence speed about 1.5~1.8 time than the present MMA that has a FIR structure of single stage.

• Journal of Broadcast Engineering
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• v.13 no.2
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• pp.188-199
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• 2008

In conventional video coding, encoder complexity is much higher than that of decoder. However, investigations for lightweight encoder to eliminate motion prediction/compensation claiming most complexity in encoder have recently become an important issue. The Wyner-Ziv coding is one of the representative schemes for the problem and, in this scheme, since encoder generates only parity bits of a current frame without performing any type of processes extracting correlation information between frames, it has an extremely simple structure compared to conventional coding techniques. However, in Wyner-Ziv coding, channel decoding errors occur when noisy side information is used in channel decoding process. These channel decoding errors appear more frequently, especially, when there is not enough correlation between frames to generate accurate side information and, as a result, those errors look like Salt & Pepper type noise in the reconstructed frame. Since this noise severely deteriorates subjective video quality even though such noise rarely occurs, previously we proposed a computationally extremely light encoding method based on selective median filter that corrects such noise using spatial correlation of a frame. However, in the previous method, there is a problem that loss of texture from filtering may exceed gain from error correction by the filter for video sequences having complex torture. Therefore, in this paper, we propose an improved lightweight encoding method that minimizes loss of texture detail from filtering by allowing information of texture and that of noise in side information to be utilized by the selective median filter. Our experiments have verified average PSNR gain of up to 0.84dB compared to the previous method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.10C
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• pp.995-1006
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• 2003

It is well know that in the wireless communication systems the transmitted signals can suffer from multipath fading due to the wave propagation characteristics and the obstacles over the paths, resulting in serious reduction in the power of the received signals. However, it is possible to take advantage of the inherent diversity imposed in the multipath reception if the underlying channel can be properly estimated. One of the diversity reception methods in this case is Rake processing. In this paper we study the Rake receivers for the direct-sequence spread-spectrum communication systems utilizing PN (pseudo noise) sequences to achieve spread spectrum. A conventional Rake receiver can use the finite-duration impulse (FIR) filter followed by the PN sequence demodulator, where the FIR filter coefficients are the reverse-ordered complex conjugate values of the fading channel impulse response estimates. Here, we propose a new Rake processing method by replacing the aforementioned PN code sequence with a new set of optimum demodulator coefficients. More specifically, the concept of the new optimum Rake processing is first introduced and then the optimum demodulator coefficients are theoretically derived. The performance obtained using the new optimum Rake processing is also calculated. The analytical results are verified by computer simulation. As a result, it is shown that the new optimum Rake processing method improves the MSE performance more than 10 dB over the conventional one using the fixed PN sequence demodulator. It is also shown that the new optimum Rake processing method improves the MSE performance about 10 dB over the Adaptive Correlator that performs the combining of the multipath components and PN demodulation concurrently. And finally, the MSE performance of the optimum Rake demodulator is very close to the MSE performance of OPSK demodulator under the AWGN channel.

• Journal of Digital Convergence
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• v.20 no.4
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• pp.45-54
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• 2022

This study examines the actual operation and performance of the public participation platform by analyzing various public participation processes from 2018 to 2021, when 'Gwanghwamun 1st Street', a representative public participation platform operated by the Ministry of Public Administration and Security, was launched. Through this, the influencing factors that were able to successfully induce the process of policyization through public participation were derived as follows. First, online participation channels were diversified to encourage public participation. Second, it is also important that the public opinion contest and compensation for public review were implemented to encourage and expand public participation. Third, the participation of experts was encouraged to refine and refine the people's ideas. Through these research results, it is judged that the Korean government will be able to contribute to inducing the policyization process through continuous public participation. In deriving success factors for policyization through public participation in the future, how influencing factors such as the public participation process, communication through online channels, and collaboration with experts affect the public participation process using quantitative analysis techniques A study to prove it will have to be conducted subsequently.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.2C
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• pp.170-183
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• 2002

This paper proposes an efficient frequency and symbol synchronization structure which could solve problems of the conventional methods to implement DVB-T receive modem which adopted OFDM transmission method. The main considerations of frequency synchronization algorithms are that the frequency tracking performance is not stable enough, and lots of symbols are required, especially when the decimal part of normalized frequency offset (which original frequency offset is divided by the subcarrier spacing) is around $\pm$0.5 to solve these problems, we propose an efficient frequency offset is divided by the subcarrier spacing) is around $\pm$0.5 by using the average of coarse synchronization over several symbol. Also, we suggest a new symbol synchronization structure which is easy to implement without performance degradation in multipath fading channel with only coarse symbol synchronization by making window offset to the range of guard interval in contrast to the conventional structure of dividing symbol synchronization in fine and coarse mode during synchronization. By extensive simulation, we have shown the superiority of the proposed schemes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.4B
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• pp.291-297
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• 2002

Due to the increasing demand for high data multimedia service, there has been progressing study of adaptive smart antenna to increase both the performance and capacity using limited wireless resource. IS-95 scheme in the origin of cdma2000 of IMT-2000 standard uses signals of spreading and Walsh-Orthogonal Modulation in reverse link. But, in the case of reverse lint there exists difficulty in synchronous of signals transmitted from users. Therefore, orthogonality between users is not satisfied. So, asynchronous MC-CDMA scheme may yield low performance. In this paper, MC/DS-CDMA scheme to reverse link transmission in adaptive array antenna environment is proposed for spreading the S/P-converted data streams using a given spreading code. Due to frequency diversity effect, simulation results show that the proposed system provides improved BER performance and narrow band interference supple psi on.

• Journal of Advanced Navigation Technology
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• v.10 no.2
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• pp.103-113
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• 2006

The numerical methods of finding the optimal position of optical phase conjugator (OPC) and the optimal fiber dispersions are proposed, which are able to effectively compensate overall channels in $8{\times}40$ Gbps WDM system with non zero-dispersion shifted fiber (NZ-DSF) as an optical fiber. And BER characteristics in the system with two induced optimal parameters are compared with those in the system with the currently used mid-span spectral inversion (MSSI) in order to confirm the availability of the proposed methods. It is confirmed that two optimal parameters depend on each other, but less related with the searching procedure. The methods proposed in this research will be expected to alternate with the method of making a symmetrical distribution of power and local dispersion in real optical link which is a serious problem but the condition in the case of applying the OPC into multi-channels WDM system.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.8
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• pp.9-15
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• 2010

This paper presents an analysis of asynchronous multicarrier-code division multiple access (MC-CDMA) uplink systems over frequency-selective multipath fading channels when the frequency offsets (FOs) of all users are random variables and the frequency offset for the desired user is compensated. The effect of a residual frequency offset(RFO) on the average bit error rate (BER) is evaluated by the semi-analytical method, then the approximated BER performance is obtained as a closed-form expression. Moreover, the signal to noise ratio (SNR) loss caused by RFO is evaluated. Derived results show that the performance degradation due to RFO is negligible if the estimation error of RFO for the desired user is less than the normalized value of 0.1.