• The Journal of the Korea institute of electronic communication sciences
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• v.4 no.3
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• pp.217-223
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• 2009

Recently, the development of the various network method can generate serious social problems. So, it is highly required to control security of network. These problems related security will be developed and keep up to confront with anti-security field such as hacking, cracking. The way to preserve security from hacker or cracker without developing new cryptographic algorithm is keeping the state of anti-cryptanalysis in a prescribed time by means of extending key-length. In this paper, the proposed montgomery multiplication structured unit array method in carry generated part and variable length multiplication for eliminating bottle neck effect with the RSA cryptosystem. Therefore, this proposed montgomery multiplier enforce the real time processing and prevent outer cracking.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.3
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• pp.35-46
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• 1999

A derotator VLSI which compensates for the frequency and phase errors of a received signal in digital communication systems was developed employing a CORDIC algorithm. The CORDIC circuit directly rotates the input signal according to the phase error information, thus is much simpler than the conventional derotator architecture which consists of a DDFS (Direct Digital Frequency Synthesizer) and a complex multiplier. Since a derotator needs only small phase error accumulation, a fast direction sequence generation method which exploits the linearity of the arctangent function in small angles is utilized in order to enhance the operating speed. The chip was designed and implemented using a $0.6\mu\textrm{m}$ triple metal CMOS process by the full custom layout method. The whole chip size is $6.8\textrm{mm}^2$ and the maximum operating frequency is 25 MHz.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.8
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• pp.1488-1494
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• 2008

This paper is to design and implement a low power noncoherent BFSK receiver intended for future deep space communication using Xilinx System generator. The receiver incorporates a 16 point Fast Fourier Transform(FFT) for symbol detection. The design units of the receiver are digital design for better efficiency and reliability. The receiver functions on one bit data processing and supports main data rate 10kbps. In addition CORDIC algorithm is used for avoiding complex multiplications while computing FFT and multiplication of twiddle factor for low power is substituted by rotators. The design and simulation of the receiver is carried out in Simulink then the Simulink model is translated to the hardware model to implement FPGA using Xilinx System Generator and to verify performance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.71-80
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• 2016

Purpose: The aim of this study was to identify sexual experiences and associated factors among middle and high school students in Korea. Methods: Data were analyzed from 74,186 participants who completed the 2012 Korea Youth Risk Behavior Web-based Survey. Descriptive statistics were used to identify the condition of sexual behavior, and a complex sample logistic regression was used to examine the factors related to sexual behavior. Results: Data showed that 4.3% of adolescents had engaged in sexual intercourse (5.9% of males and 2.6% of females). According to the logistic regression analysis for complex samples, the school level, socioeconomic status, experience of part time work, and living with parents, were all factors associated with the decision to engage in sexual intercourse among boys and girls. In particular, sex education in schools was associated with a reduced risk of sexual intercourse. Conclusion: The results of this study highlight the importance of developing a program that focuses on enhancing sex education and promoting refusal and better decision-making skills in order to effectively reduce the likelihood of sexual experience among adolescents in Korea.

• Korean Journal of Social Welfare Studies
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• v.47 no.4
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• pp.361-388
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• 2016

The purpose of the study was to conduct an empirical study on the scope and level of social exclusion experienced by persons with psychosocial disabilities. The Wave 6 data of the Panel Survey of Employment for the Disabled were used to investigate the current status of social exclusion in life areas including income, education, work, housing, health, social network, social participation, and discrimination (N=4,161). A series of logistic regressions were executed, with the psychosocial disability(PD) group being the reference; the reverse odds rations of different disability groups were compared against the PD reference group (OR=1). The results showed that compared with all others, the PD group was about 2 to 11 times more likely to have risks in income, work, and housing; and that compared to other groups except for the autism/developmental disability group, they were about 6 to 10 times more likely to have risks in social network, social participation and discrimination. In conclusion, the authors urged the need for legal mandates to have community based mental health services and welfare services for the disabled more available to the PD groups and the necessity to eliminate various discriminatory legislations that are violating human and social rights of the persons with PDs.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.1
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• pp.101-106
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• 2020

This paper relates with the VS-QE-MMA (Varying Stepsize-Quantized Error-MMA) based on the varying stepsize for improving the equalization performance in the QE-MMA adaptive equalization algorithm that is possible to reducing the intersymbol interference occurred at channel. The SE-MMA use the high-order statistics of transmitted signal and sign of error signal. The QE-MMA was appeared for the H/W implementation easiness substitutes the multiplication and substraction into the shift and substraction in the updating the tap coefficient based on the power-of-two operation of error signal magnitude. The QE-MMA gives degradation of equalization performance due to the such simplification of arithmetic operation. For improving this problem, the propose algorithm, namely VS-QE-MMA, applies the varying stepsize of the nonlinear transformation of error signal. It was confirmed by simulation that the VS-QE-MMA gives better performance than current QE-MMA in the same channel and signal to noise ratio. As a result of simulation, the VS-QE-MMA has more better performance in the every performance index, and it was also confirmed that the varying stepsize effect can be obtained in the greater than 10dB of signal to noise ratio.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.11C
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• pp.1107-1119
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• 2006

Data transmission experiences multiplicative distortion in frequency nonselective fading channel. This distortion occurs in OFDM communication channel and can be compensated using an equalizer. Usually, in the case of LMS equalizer, eigenvalue distribution of training signal is enlarged. Large eigenvalue distribution causes principally the performance of a communication system to be deteriorated. This paper proposes a new algorithm that shows the same performance as the existing fast wavelet transform algorithm with less computational complexity. The proposed algorithm was applied to an adaptive equalizer of OFDM communication system. Matlab simulation results show a better performance than the existing one. The proposed algorithm was implemented in VHDL and simulated.

• Journal of the Korean Institute of Telematics and Electronics
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• v.20 no.6
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• pp.6-10
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• 1983

In this paper, an implementation method for digital filters using the residue arithmetic is proposed. This method can be used for processing digital signals with larger number of bits by applying the idea of the bit-slice algorithm, while previous residue digital filters can process digital signals with only a small number of bits. Furthermore, high-speed residue addition, subtrac-tion, and multiplication using look-up tables make it possible to get more flexible filters. Everything that is mentioned above is proved by implementing a cascade fourth-order Butterworth lowpass digital filter using this method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.11 no.4
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• pp.251-258
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• 1986

There is much redundancy in image data such as TV signals and many techniques to redice it have been studied. In this paper, Hadamard transform is studied through computer simulation and experimental model. Each element of hadamard matrix is either +1 or -1, and the row vectors are orthogonal to another. Its hardware implementation is the simplest of the usual orthogonal transforms because addition and sulbraction are necessary to calculate transformed signals, while not only addition but multiplication are necessary in digital Fourier transform, etc. Linclon data (64$ imes$64) are simulated using 8th-order and 16th-order Hadamard transform, and 8th-order is implemented to hardware. Theoretical calculation and experimental result of 8th-order show that 2.0 bits/sample are required for good quality.

• Journal of Korean Society of Transportation
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• v.27 no.2
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• pp.107-115
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• 2009

Traffic islands were introduced for drivers and pedestrians to use the road in a safe and orderly way and were also a specified zone between traffic lanes to divide conflicting traffic flows and to provide pedestrian refuge. However, existing research and relevant standards described its purpose and effects only but not a safety standard to decide whether the traffic island warranted. This study was to introduce a parameter which had a high relationship with accidents by analyzing road and traffic conditions and traffic accident data at urban intersections. Based on the relationship between the parameter and the traffic accidents at the intersection, a pedestrian accident probability model was made by using a logit model. In addition, the study reviewed a pedestrian accident probability corresponding to traffic volume and size of the intersection during design of the intersection and then suggested the effectiveness of the traffic island in terms of traffic safety. In conclusion, when a large-scale intersection has significant traffic volumes, a high probability of traffic island-induced pedestrian accidents appears, while in the case of small volumes, the probability is low. Targeted design and operations of a traffic islands is necessary, because its introduction itself does not enhance pedestrian safety in all cases at all intersections. This study can be a useful reference for further development to set up a scheme of the traffic islands in terms of traffic safety.