• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.45 no.2
• /
• pp.92-96
• /
• 2008

Practical communication systems need to operate at various different rates. This paper describes and analyzes low-density parity check codes for various different rates. From a specific mother code, it allows LDPC codes for different rate. The advantage of this technique is that each different rate LDPC codes have a same block length as mother code though the rate changes so it can make up for the weak points of puncturing and shortening which reduce their block length as the rate changes. Row-splitting method is to split the row, so that the rate changes from a higher rate to lower rate and cause of its own property, it can overcome the defect of row-combining method.

• Journal of Korea Society of Industrial Information Systems
• /
• v.20 no.6
• /
• pp.21-27
• /
• 2015

We analyze the problem that is occurring when using parity mode transformation required for 9 bit serial communication under Linux environment and propose the solution. The parity mode change is used for 9 bit serial communication in the Linux that by nature supports only 8 bit serial communication. delay (around OS tick) arises. Our analysis shows that the cause is minimum length of waiting time to transmit data remained in Tx FIFO buffers. A modified Linux serial driver proposed in this paper decreases the delay less than 1ms by using accurate time delaying. Despite various system communication interfaces, enormous existing standards and system have adopted RS-232 serial communication, and the part of them have communicated by 9bit serial.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.35 no.11C
• /
• pp.901-906
• /
• 2010

Low density parity check (LDPC) code, first introduced by Gallager and re-discovered by MacKay et al, has attracted researcher's interest mainly due to their performance and low decoding complexity. It was remarkable that the performance is very close to Shannon capacity limit under the assumption of having long codeword length and iterative decoder. However, comparing to turbo codes widely used in the current mobile communication, the encoding complexity of LDPC codes has been regarded as the drawback. This paper proposes a solution for DVB-S2 LDPC encoder to reduce the encoder latency. We use the fast IRA encoder that use the transformation of the parity check matrix into block-wise form and the partial parallel process to reduce the number of system clocks for the IRA code encoding. We compare the proposed encoder with the current DVB-S2 encoder to show that the performance of proposal is better than that of the current DVB-S2 encoder.

• Journal of Dairy Science and Biotechnology
• /
• v.34 no.3
• /
• pp.193-198
• /
• 2016

This study examined changes in the components of dairy cow colostrum 1-5 days post delivery and between 1-5 days post-delivery, the contents of major proteins were largest on the first day, but declined gradually over time. Immunoglobulin, lactoferrin, bovine serum albumin, and lactoperoxidase exhibited the highest concentrations one day post-delivery. However, these levels decresed significantly on the second day and remained at a low level on the third. An examination of daily changes in colostrum composition in dairy cows after delivery, according to parity, could not detect changes in the levels of most proteins.

• Journal of Broadcast Engineering
• /
• v.17 no.1
• /
• pp.122-128
• /
• 2012

Because of the system delay caused by the number of feedback retransmission in Distributed Video Coding (DVC) scheme, it is difficult to realize practical DVC in many cases. In this paper low feedback retransmission Distributed Source Coding (DSC) scheme is proposed for practical DVC scheme based on Low-Density Parity-Check (LDPC) codes because DVC system is an specific application of DSC system. This DSC scheme is achieved by using different LDPC codes optimized in each different compression rate and using source revealing scheme. Optimized LDPC codes provide us much better decoding performance which causes the 57% reduced number of iteration. Consequently, the number of feedback retransmission is decreased by 50%.

• Korea journal of population studies
• /
• v.17 no.2
• /
• pp.77-97
• /
• 1994

Despite the fact that the national family planning program in korea has accomplished its primary goals of fertility reduction and universal contraceptive use, the induced abortion is still high and there has been an increasing trend in the population sex ratio at birth. It seems that the changes in the imbalance of sex ratio have originated from traditonal boy preference. This indicates that much of the current family planning program can be overhauled, so that the program quality could be better controlled, by preventing the number of unwanted pregnancies and the imbalance of sex ratios. This paper aims, therefore, to examine the determinants of induced abortion through the investigation of pregnancy outcomes and their changes over time and to study the interaction between induced abortion, boy preference and the imbalance of sex ratio in Korea. The abortion rate had increased rapidly until the mid-1980s when there were about the same number of abortions as live births. Thereafter, the abortion rate has been maintained at this high level. By parity it shows a much higher abortion rate for a higher parity at all time. From the first parity, the sex composition of previous children stands out as the most important factor in deciding the pregnancy outcome at all time. The probability of a pregnancy ending in an abortion increases substantially when parents already had a son. The decline of the desired family size and the sustained strong son preference has made the sex of children a more important factor in the determination of the pregnancy outcome. Women's education has had consistently positive effects on the probability of a pregnancy ending in an abortion, but the effect shows a steady decline over time. The premarital pregnancy and urban residence also increase the abortion probability. This study suggests that the main concerns of the family planning program should be to strengthen the social support policies so as to weaken the son preference value leading to a balanced sex ratio and prevention of induced abortions.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2009.10a
• /
• pp.405-409
• /
• 2009

In this paper, the effects of LLR (Log-Likelihood Ratio) approximation on LDPC (Low-Density Parity-Check) decoder performance are analyzed, and optimal design conditions of LDPC decoder are derived. The min-sum LDPC decoding algorithm which is based on an approximation of LLR sum-product algorithm is modeled and simulated by MATLAB, and it is analyzed that the effects of LLR approximation bit-width and maximum iteration cycles on the bit error rate (BER) performance of LDCP decoder. The parity check matrix for IEEE 802.11n standard which has block length of 1,944 bits and code rate of 1/2 is used, and AWGN channel with QPSK modulation is assumed. The simulation results show that optimal BER performance is achieved for 7 iteration cycles and LLR bit-width of (7,5).

• International Area Studies Review
• /
• v.13 no.3
• /
• pp.827-848
• /
• 2009

The purposes of this study are followings. First, I will compare the effects of wive's characteristics with the effects of the husbands' characteristics on the contraceptive use. Second, I will analyzed whether the determinants of the contraceptive use have changed according to parties. Third, I will analyzed whether the determinants of the contraceptive use at each parity have changed according to periods-especially, after and before economic crisis. According to expectation, the ratios using the contraception are affected by the wive's and husband's demographic characteristics, the determinants affecting the contraceptive use have changed by both parity and periods. The other findings are follows. First, women's employment status have positive effects on the contraceptive use, regardless parties and periods. Second, the ideology emphasizing the relationship between parents and children, rather than the ideology emphasizing the relationship between husband and wife, is more like to affect the contraceptive use.

• Animal Bioscience
• /
• v.34 no.4
• /
• pp.575-583
• /
• 2021

Objective: The aim of the study was to determine the effect of parity and the stage of lactation on the metabolic profile of cows based on the basic chemical milk components and the blood parameters. Methods: The study material consisted of high-yielding Holstein-Friesian cows. In total, 473 cows were examined. According to the parity, cows were divided into four groups: primiparous (P), and multiparous in the second (M2), in the third (M3), and in subsequent lactations (M4). The feeding of cows was based on total mixed ration (TMR) ad libitum. Milk and blood samples were collected individually from each cow three times per standard lactation period. Results: Greater exacerbation of changes in the dynamics of the blood plasma parameters examined was proved for multiparous cows. The highest value of β-hydroxybutyrate acid (0.946 mmol/L) was found for multiparous cows from group M3 at the beginning of lactation. However, it was still in the normal range. The results showed aspartate aminotransferase, and gamma-glutamyl transferase (GGT) activities in dairy cows during lactation had significant variations taking in to account stage of lactation. The highest activity of GGT was found in the group of the oldest cows and measured from 26.36 U/L at the beginning of lactation to 48.75 U/L at the end of the lactation period. Conclusion: The time-related changes in the concentrations of the biochemical parameters described differ markedly among lactating cows, though the housing conditions on the research dairy farm are highly standardised. This indicates that the ability to cope with metabolic stress is mainly affected by the individual predispositions of cows and feed nutrient supply in different stage of lactation. Especially, the feed nutrient supply (in net energy for lactation), which was the best in TMR 1 in comparison TMR 3.

• International Area Studies Review
• /
• v.21 no.4
• /
• pp.141-158
• /
• 2017

The purpose of this study is to firstly estimate the inflation rate of North Korea using relative purchasing power parity. Most of the existing studies use North Korean rice prices as proxy to explain changes in North Korean prices. In this study, North Korea's price was estimated by applying purchasing power parity, which was used to estimate the price of socialist countries in the past, to North Korea. Second, it analyzes the impact of North Korea's price inflation after the institutional change of currency reform. We looked at the movements of North Korean prices after the institutional change of currency reform and compared it with the post-monetary reform of other socialist countries. We examine the impact of currency reform on North Korea, focusing on the price. As a result, after the currency reform in 2009, North Korea experienced hyperinflation. The North Korean inflation rate in the model was 3,010.0% in 2010, 195.0% in 2011, 68.0% in 2012 and 48.3% in 2013. After the currency reform of North Korea, the inflation rate is much higher than the socialist countries such as China and Vietnam who had experienced currency reform before. North Korea's monetary reforms are considered to have failed because of the side effects of hyperinflation.