• Journal of the Korean Institute of Telematics and Electronics S
• /
• v.35S no.11
• /
• pp.12-18
• /
• 1998

In non-geostationary orbit(NGSO) satellite communication links, satellite's elevation angle at terminal is changed continuously because of the satellite movement relative to earth surface. Therefore the characteristics of the fade-effected signal received by a terminal from a NGSO satellite is also varied continuously even if the terminal is operated at fixed location. In this paper, we determine a general statistic model for the fading characteristics over NGSO satellite communication links and set up the parameters of the fading model in terms of the elevation angle according to various propagation environment and find the parameter values using the data of fading margin for commercial NGSO mobile satellite communication systems. And the fading charateristics for each environment are analyzed using this model. These results can be applied to develop the compensation algorithm and to analyze the performance of the transmission schemes for NGSO mobile satellite communication systems.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.46 no.8
• /
• pp.86-94
• /
• 2009

An idea to improve the performance of error correction with the amplification of input symbol errors is proposed to ease the mismatching problem which occurs in the hardware implementation of the differential analog PRML decoder. The differential analog PRML decoder is the decoder with two blocks of trellis diagram one of which is without branches of "0" and the other one is without the branches of "1". Decoding is performed by comparing the outputs of two blocks. The decoding error is likely to occur when the difference of two outputs is very small and the hardware implementation is not precise due to mismatching. The proposed idea is to increase the discrimination margin for the output "0" and "1" by amplifying the symbol error while the larger path metrics are saturated. To show the performance improvement of decoding with the proposed idea, simulation results are included

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.46 no.8
• /
• pp.71-78
• /
• 2009

An 8${\times}$8-Gb/s/channel 4-PAM transceiver was designed for high speed memory applications by using 70nm DRAM process with 1.35V supply. An asymmetric 4-PAM signaling scheme is proposed to increase the voltage and time margin of upper and lower eyes in 3-class eye opening. A mathematical basis shows that this scheme statistically reduces 33% of reference noise effect in a receiver. Also, an adaptive pre-emphasis scheme, which utilizes a lone-bit pulse with integrator at the receiver, is introduced to reduce ISI for a simple DRAM channel. In this scheme, an integrating clock timing calibration by using a pre-determined pattern is proposed for the optimum ISI measurement.

• Korean Journal of Pharmacognosy
• /
• v.44 no.2
• /
• pp.125-130
• /
• 2013

Samchulgeonbi-tang (SC) is well-known traditional herbal medicine which is composed of fourteen medicine herbs. SC has been used for the treatment of the chronic gastritis, indigestion, gastric ulcers, gastroptosis and diarrhea disease. The variation in the amount of bioactive components of SC and its fermentation SC with ten Lactobacillus strains were investigated via high-performance liquid chromatography coupled with diode array detection (HPLC-DAD). Simultaneous qualitative and quantitative analysis of seven bioactive compounds; paeoniflorin, liquiritin, hesperidin, liquiritigenin, kaempferol, atractylenolide III, magnolol were achieved by comparing their retention times ($t_R$) and UV spectra with those of the standard compounds. In the results, the amount of paeoniflorin and hesperidin were 7.967 mg/g, 7.251 mg/g that were the main compounds in SC. The amounts of liquiritigenin was increased by all ten Lactobacillus strains, except strain 128. Especially, the liquiritigenin amount was highest in SC fermented with strain 145 (0.201 mg/g), which was increased by 158.39% compared to SC (0.081 mg/g). In the fermented SC using strains 344, almost components were increased than non-fermented SC, except paeoniflorin and kaempferol. Thus, these results considered that the strains 145 and 344 are most excellent fermentation strains among the 10 species of fermentation strains.

• The Korea Journal of Herbology
• /
• v.22 no.2
• /
• pp.97-102
• /
• 2007

Objectives : This study presents a high performance liquid chromatography - electrospray ionization-mass spectrometer (HPLC-MS/MS) methods for the quantitative and qualitative analysis of various active components in Samul-tang, which is composed of four crude herbs. Methods : HPLC-ESI-MS/MS for the determinations of paeoniflorin and 5-HMF (5-hydroxymethyl 2-furaldehyde) in the Samul-tang, the separation method was performed on an COSMOS1L 5C18-AR-Il (2.0 X 150 mm I.D.) column by gradient elution with 0.1% acetic acid and 5% CH3CN in water (A)-0.1% acetic acid and 5% H20 in CH3CN (B) as the mobile phase at a flow-rate of 300 ${\mu}L/min$ with detection at quadrupole mass spectrometer. The all marker substances were always detected as the base peaks in the positive ion mode. Results : The paeoniflorin of Paeoniae Radix in Samul-tang showed a strong base peak [M+H2O]+ in the positive detection mode to give the following as; paeoniflorin (498.109 [M+H2O]+, 479.8 [M]+, 301 [M-glucose]+, 179.3 [glucose]+). Based on the HPLC retnetion time and MS of standard compounds confirmed the identity of active compounds in Rehmanniae Radix Preparata as follows; 5-HMF (127.0[M+H]+, 109.3 [M-OH]+) in the positive ion mode. Conclusion : According to the above results, HPLC-ESI-MS method permits assignment of tentative structures such as paeoniflorin and 5-HMF in the Samul-tang.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.06a
• /
• pp.153-153
• /
• 2009

We investigated the dependence of the memory margin of the Cap-less memory cell on the strain of top silicon channel layer and also compared kink effect of strained Cap-less memory cell with the conventional Cap-less memory cell. For comparison of the characteristic of the memory margin of Cap-less memory cell on the strain channel layer, Cap-less transistors were fabricated on fully depleted strained silicon-on-insulator of 0.73-% tensile strain and conventional silicon-on-insulator substrate. The thickness of channel layer was fabricated as 40 nm to obtain optimal memory margin. We obtained the enhancement of 2.12 times in the memory margin of Cap-less memory cell on strained-silicon-on-insulator substrate, compared with a conventional SOI substrate. In particular, much higher D1 current of Cap-less memory cell was observed, resulted from a higher drain conductance of 2.65 times at the kink region, induced by the 1.7 times higher electron mobility in the strain channel than the conventional Cap-less memory cell at the effective field of 0.3MV/cm. Enhancement of memory margin supports the strained Cap-less memory cell can be promising substrate structures to improve the characteristics of Cap-less memory cell.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.12 no.2
• /
• pp.184-192
• /
• 2001

In this paper, we analyze the result of the conduced emission and susceptibility tests performed on the KOMPSAT-I ETB Platform. The ETB platform consists of the EM (Engineering Model) boxes developed to perform the electrical functional test. During the conducted emission test, we measured the instant waveform in time domain when each switch was turn on, and spectrum of the noise in the frequency range of 10 Hz up to100 MHz fur the steady state of the ETB. During the conducted susceptibility test, no malfunction and no serious damage of the electronic box were observed when a simulated noise waveform was applied to the DC power bus. The simulated waveform was obtained by adding the 6 dB-system margin to the worst case waveform measured from the conducted emission. This test was performed as co-development of the KOMPSAT-I with TRW in USA.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.16 no.7 s.98
• /
• pp.732-739
• /
• 2005

In this paper, the design and implementation of the Ka-band(20/30 GHz) waveguide diplexer with an E-plane T-junction are described. The waveguide diplexer consists of a transmit filter and a receive filter combined to the antenna port via an E-plane T-junction. The reason why the E-plane T-junction structure was selected is to reduce PIM(Passive Intermodulation) level as the split-plane is located in the low electrical current zone. The optimization was performed using the equivalent circuit so that the computation time might reduce. The structure of the diplexer was designed to handle high power and the multipaction analysis was performed. The multipaction margin was greater than 12 dB and satisfied with ESA/ESTEC recommendation. The manufactured diplexer shows minimum return loss of 22 dB, maximum insertion loss of 0.20 dB and maximum isolation of -40 dB for both transmitted receive bands. Those mean the analysis results of the waveguide diplexer were well agreed with the electrical performance test.

• The Korea Journal of Herbology
• /
• v.22 no.3
• /
• pp.77-83
• /
• 2007

Objectives : The purpose of this study was to examine the effects of the Hominis placenta extracts on improvement of senile osteoporosis (Type 2) in SAM P6. In traditional Oriental medicine, Placenta (Jahageo) is indicated for insufficiency of blood and tidal fever due to steaming bone disorder. Methods : At 10 weeks after birth, Placenta ex. was given 100 mL, 200 ml/kg/day, i.p. 3 times a week for 4 weeks in SAM P6 mice. And then we measured complete blood cells, blood urea nitrogen, creatinine, inorganic phosphate and total iron. In addition, we tested bone mineral density (BMD) using the soft X-ray. Results : As a result, in SAM P6, injection of Placenta ex. (200 mL) increased in RBC, HB and PLT, in comparison with control group. It was also found that the inorganic phosphate levels increased significantly in the injection groups of the Placenta ex. from that of the control group, but blood urea nitrogen was no significant. Moreover, Placenta ex. were showed a trend of increase in bone mineral density (BMD) of the vertebrae lumbales and tibia in P6 mice. Conclusions : These findings suggest that Placenta ex. are effective in preventing bone loss in SAMP6.

• Aerospace Engineering and Technology
• /
• v.9 no.2
• /
• pp.161-167
• /
• 2010

CEU(Camera Electronic Unit) loaded in optical satellite for a high resolution image acquisition is composited with CC(Camera Controlloer), FPA(Focal Plane Assembly) and CEUP(CEU Power supply). EMC test and analysis results are explained in this paper. CE, CS, RE and RS test is performed in the 1st EMC test, RE, RS test which is not complied and influence considerably after shielding structure is performed in the 2nd EMC test. An effect due to the noise of CEU in the GPS/S-band receiving band is analyzed based on 2nd EMC test results. Margin more than 6dB is guaranteed when CEU is shielded.