• ETRI Journal
• /
• v.21 no.2
• /
• pp.9-21
• /
• 1999

In this paper, to enhance the performance of ${\pi}$/4-DQPSK (${\pi}$/4-differential quadrature phase shift keying), the scheme using nonredundant multiple error correction is proposed and investigated. This scheme for the differential detection of ${\pi}$/4-DQPSK uses the signal output which is delayed for more than two time slots as the parity check bit and applies it to nonredundant multiple error correction. The proposed system was used for studying the performance of ${\pi}$/4-DQPSK with Nonredundant Error Correction (NEC) in additive white Gaussian noise (AWGN) and Nakagami fade modeled mobile communication channel, and it was observed that the performance increased as the error correction capability increased.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.07b
• /
• pp.1212-1216
• /
• 2003

In this study, the ${\pi}/4$ shift QPSK(quadrature phase shift keying) with NEC(nonredundant error correction) on the multipath channel can detect the burst error as well as random error one by using the second and L-th order phase difference. Therefore, the BER(bit error rate) performance in ${\pi}/4$ shift QPSK is more improved than that of the ${\pi}/4$ shift QPSK without NEC structure. Also, this performance become a bit better in Rayleigh fading channel.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.60 no.10
• /
• pp.1978-1983
• /
• 2011

BLDC motor is used in a wide variety of industrial and servo applications. Its features and advantages mainly consist in high value of torque/inertia ratio, high efficiency with speed range and high dynamic performance. This paper deals with the speed control of a trapezoidal type brushless DC motor using Fuzzy PI controller. The conventional PI controller has been widely used in industrial applications. If we select a optimal PI control gain, the PI controller shows very good control performance. But it is very difficult to find the optimal PI control gain. Fuzzy control does not need any model of plant and is basically adaptive and gives robust performance for plant parameter variation. Therefore the combinations of conventional PI controller and fuzzy controller seem to be very effective. This paper deals with PI controller with 4-rule based fuzzy controller. The proposed fuzzy PI controller increases the control performance of the conventional PI controller. Simulation and experimental results show that fuzzy PI controller has a good robustness regarding the improper tuned PI controller.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.6 no.4
• /
• pp.535-543
• /
• 2002

In this paper, we propose $\pi$/8 shift 8PSK and trellis-coded $\pi$/8 shift 8PSK-OFDM techniques by applying $\pi$/4 shift QPSK to trellis-coded modulation (TCM), and performing signal set expansion and set partition correspondingly based on phase difference. In our Viterbi decoding algorithm, up to L phase differences from successively received symbols are employed in the new branch metrics. Such sliding multiple symbol detection (SMSD) method provides improved bit-error-rate (BER) performance in the differential detection of the trellis-coded $\pi$/8 shift 8PSK-OFDM signals. The performance improvements are achieved for different communication channels without sacrificing bandwidth and power efficiency. It thus makes the proposed modulation and sliding detection scheme more attractive for power and band-limited systems.

• Journal of the Korean Magnetics Society
• /
• v.10 no.1
• /
• pp.30-36
• /
• 2000

SmCo films were deposited on Si(100) substrate by a Nd-YAG pulsed laser ablation of the targets of Sm$\_$100-x/Co$\_$x/ (73$\leq$x$\leq$93) at the substrate temperature of 600∼700$\^{C}$ and the laser beam energy density of Q switching mode or fixed Q mode. The magnetic properties of the films obtained from the Q switching mode exhibited a 4 $\pi$ Ms of 5200∼7700 Gauss, iHc of 190-250 Oe, and 4$\pi$M$\_$r//4$\pi$M$\_$s/ of 0.4∼0.74, respectively, while the fixed Q mode gave the magnetic properties of corresponding films of a 4$\pi$M$\_$r//4$\pi$M$\_$s/ = 0.32∼0.91 and iHc of 430-6290 Oe, respectively. The fixed Q mode gave the better magnetic properties of the SmCo films which seems to be due to a formation of magnetically hard minor phases in droplet of Sm-rich intermetallics. However, the resultant rough surface of the SmCo films is a problem to be solved by a continued study.

• Journal of the Korea Fashion and Costume Design Association
• /
• v.7 no.1
• /
• pp.65-75
• /
• 2005

The purpose of this paper is to understand the formal characteristics of Pi-Ling by investigating the Pi-Ling(披領)'s system of Qing Dynasty. As a research document, Qing-Huidian-Tu(淸會典圓) has been used. The following results were found out in this research; 1) The form of Pi-Ling was horizontally wide and both sides were narrow and sharp. There was a circular hole in the center of Pi-Ling. It was worn around the neck by a button in its front center. 2) materials: The materials of Pi-Ling were the leather of marten or sea-lion, satins, and silk. 3) The color of Pi-Ling was purple or blue. 4) Moving dragons(行龍) were used on the pattern of Pi-Ling. And the Pi-Ling of low level officials had no patterns.

• Journal of Korea Entertainment Industry Association
• /
• v.14 no.4
• /
• pp.199-209
• /
• 2020

"Positive Influence(PI)" of popular star has recently emerged as a social concern, but the lack of prior research has led to confusion over its concept and range of activity. On this point, this study carried out to lay the groundwork for discussions on the systematization of related theories, focused on identifying the current situations by analyzing articles for 15 months from January 2019 to March 2020 when related reports were in full swing. As a result of the analysis of the remarks from the entertainers mentioned in the articles, they were not clearly aware of the concept while doing good deeds under the name of PI in light of the study outcome by Aegean and Singer(2013). The motivations for good deed were classified into six types, including difficulty empathy, fandom reward, participation urge, nidana emphasis, experience subjugation, and memory evocation in the order of frequency of cases. Specific behaviors of PI were followed by donations of money and valuables for 54.4 percent, participation of social agendas for 14.0 percent, volunteering for 13.2 percent, joining campaign for 11.4 percent, other good deeds for 4.0 percent, and philanthropy for 3.0 percent. In occupational analysis, the concentration of donations was also evident. Their activities in the fields of human rights sensitivity, environmental protection and self-management, which are expected to have great effects with their influence, have been extremely poor. The results of the study first require academia to establish a interdisciplinary concept for PI. It also suggests that entertainers and their agencies should take far more strategic approach to evolve the PI event in a way that utilizes the advantages of each job group, such as actors, singers and comedians, and expands the diversity of areas.

• Korean Journal of Veterinary Research
• /
• v.35 no.1
• /
• pp.107-113
• /
• 1995

Four Holstein calves 7-day-old were infected with C parvum oocysts for parasitological and pathological investigations of bovine cryptosporidiosis. Of those calf 1 was orally administered with $7{\times}10^6$ oocysts of C parvum isolated from a Korean mouse (VRI-CN91), and calf 2 with same number of C parvum oocysts provided by Washington State University(WSU). The rest (calf 3 and 4) were orally administered with $1{\times}10^8$ oocysts of VRI-CN91 strain. Calf 1 commenced to discharge oocysts in feces at days 6 post inoculation(PI), and it reached a peak $1.4{\times}10^7$ oocysts per gram of feces(OPG) on day 8 PI. Calf 2 commenced to discharge oocysts in feces at day 4 PI, and it reached a peak $3.75{\times}10^6$ OPG on day 7 PI. Calf 3 and 4 commenced to discharge oocysts in feces at day 3 and day 4 PI, and it reached a peak on day 7 PI (calf 3, $7.8{\times}10^6$ OPG; calf 4, $1.7{\times}10^6$ OPG). Clinically, the calves began to show mucoid-watery diarrhea at day 3 to 5 PI, and the sign lasted 5 to 7 days. Calf 2 died on day 9 PI with a severe dehydration. On necropsy the intestine was found to be congested and hemorrhagic. Protozoan oocysts were observed mainly in the ileum and occasionally in jejunum. The results in the present study indicate that the Korean isolate was pathogenic in calves.

• Journal of Life Science
• /
• v.32 no.10
• /
• pp.762-770
• /
• 2022

Hyperglycemia in type 2 diabetes can be alleviated by promoting cellular glucose uptake. Betulinic acid (3β,-3-hydroxy-lup-20(29)-en-28-oic acid) is a pentacyclic lupane-type triterpenoid compound. Although there have been studies on the antidiabetic activity of betulinic acid, studies on cellular glucose uptake are lacking. We investigated the effects of betulinic acid on glucose uptake and its mechanism of action in 3T3-L1 adipocytes. Betulinic acid significantly stimulated glucose uptake in 3T3-L1 adipocytes by increasing the phosphorylation of the insulin receptor substrate 1-tyrosine (IRS-1tyr) in the insulin signaling pathway, which in turn stimulated the activation of phosphoinositide 3-kinase (PI3K) and the phosphorylation of protein kinase B (Akt). The activation of PI3K and Akt by betulinic acid translocated glucose transporter 4 to the plasma membrane (PM-GLUT4), thereby increasing the expression of PM-GLUT4 and thus stimulating cellular glucose uptake. Betulinic acid also significantly increased the phosphorylation/activation of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase. The activation of PI3K and AMPK by betulinic acid was confirmed using the PI3K inhibitor wortmannin and the AMPK inhibitor compound C. The increase in glucose uptake induced by betulinic acid was significantly decreased by wortmannin and compound C in the 3T3-L1 adipocytes. These results suggest that betulinic acid stimulates glucose uptake by activating PI3K and AMPK in 3T3-L1 adipocytes.

• Journal of Bio-Environment Control
• /
• v.21 no.1
• /
• pp.33-38
• /
• 2012

Growth response of 'Sambokkul' watermelon grafted onto different rootstocks including 4 $Citrullus$ rootstocks and 3 other cucurbitaceous rootstocks was evaluated at two different temperature regimes. Significant reduction in plant growth rate was observed in plants grown at low temperatures (LT) as compared to those grown at normal or optimal temperatures. Relative growth reduction were 40~47% for vine length, 39~51% for total leaf area, 38~59% for shoot fresh weight, and 57~87% for plant dry weight, respectively. Watermelon rootstock PI 482322 showed comparable plant growth as the most popular rootstock 'Shintozwa' even at LT. 'Sambokkul' watermelon grafted onto watermelon hybrids, 'PI 271969 ${\times}$ PI 296341' and 'PI 271769 ${\times}$ Calhoun Gray', showed comparable plant growth as 'FR Dantos' bottle gourd rootstock. Index of growth ability at LT, which was calculated on the basis of reduced rate of vine length, dry weight and leaf area, was significantly high in $C.$ $martinezii$, 'Shintozwa', PI 482322, and 'PI 271769 ${\times}$ PI 296341' rootstocks (50% or higher) and low in own-rooted 'Sambokkul' or in watermelon plants on 'Knight' rootstock. Watermelon hybrids, 'PI 271969 ${\times}$ PI 296341' and 'PI 271769 ${\times}$ Calhoun Gray', showed better or at least comparable growth at low temperatures as compared to 'FR Dantos', confirming the feasibility of using watermelon rootstocks even in low temperature conditions.