• Asian-Australasian Journal of Animal Sciences
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• v.16 no.1
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• pp.70-76
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• 2003

Three experiments were conducted to determine the effects of a sorghum-specific enzyme system, derived from an Aspergillus niger and Bacillus subtilis fermentation extract (carbohydrase activity of 1,650 $\alpha$-amylase units and cellulase activity of 30 fibrinolytic units/mL), on growth performance of finishing pigs. In Exp. 1,192 pigs (average initial BW of 46.1 kg) were fed sorghum-based diets without or with 360 mL of enzyme system per ton of sorghum in a 78 d growth assay. For d 0 to 39, gain/feed was improved (p<0.03) with enzyme supplementation, but ADG was not affected (p>0.15). For d 39 to 78 and overall (d 0 to 78), ADG, gain/feed, and digestibilities of DM and N were not affected (p>0.13) by enzyme supplementation. Backfat thickness, fat-free lean index, and scores for stomach keratinization and ulcers also were not affected (p>0.15) by the dietary treatments. In Exp. 2,168 pigs (average initial BW of 58.4 kg) were fed diets without or with 150, 300, or 450 mL/ton of the same enzyme system used in Exp. 1. Adding as much as 450 mL enzyme system / ton of sorghum did not affect (p>0.15) ADG or gain/feed for d 0 to 29 of the growth assay. However, during d 29 to 63, ADG increased by 11% (linear effect, p<0.02) and gain/feed increased by 10% (linear effect, p<0.06) as enzyme concentration was increased from none to 450 mL/ton of sorghum. For the overall period (d 0 to 63), ADG tended to increase (p<0.08) with enzyme supplementation, but gain/feed and digestibilities of DM and N were not affected (p>0.14). Carcass characteristics (dressing percentage, backfat thickness, and fat free lean index) also were not affected (p>0.20) by addition of the enzyme system. In Exp. 3,176 pigs (average initial BW of 46.7 kg) were fed diets without or with 450, 900, or 1,350 mL/ton of the same enzyme system used in Exp. 1 and 2 in a 71 d growth assay. Adding up to 1,350 mL/ton of enzyme had no effects (p>0.15) on ADG, gain/feed, digestibilities of DM and N, and carcass characteristics (dressing percentage, backfat thickness, and fat-free lean index). In conclusion, finishing pigs fed diets with a sorghum-specific enzyme system showed some positive trends for improved growth performance, but those effects were not large and (or) consistent.

• Journal of the Korean Chemical Society
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• v.10 no.3
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• pp.109-113
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• 1966

By the micro-bioassay method, quantitative studies were made on the increment of body weight and changes in free-lysine and threonine contents in the liver and plasm of rats, when they were fed on sucrose diet added with 0.3% DL-methionine, 0.36% DL-threonine and 0.1% L-tryptophane. The results of the experiment were as follows: (1) The weight gain and growth gain of rats decreased more when they were fed on 0.36% DL-threonine diet (Sth-group) than 0.3% DL-methionine diet (Sm-group). But those gain were increased when they were fed on 0.1% L-tryptophane diet (Str-group). (2) The contents of free-lysine and threonine in plasm and liver of rats were decreased more when they were fed on 0. 36% DL-threonine diet than 0.3% DL-methionine diet. And, those free amino acids were increased greatly when they were fed on 0.1% L-tryptophane diet. (3) The increment of body weight was the biggest when the free amino acid pattern showed that the contents of free-lysine decreased and threonine increased in the plasm and liver of rats being fed on 0.l% L-tryptophane diet.

• Proceedings of the KIEE Conference
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• 2003.11b
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• pp.111-114
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• 2003

In this paper, we consider the stabilization and $H_\infty$ control of linear systems with static output feedback control. The static output feedback control represents the simplest closed-loop control that can be realized in practice, and, moreover, it is less expensive to be implemented and is more reliable. In spite of its advantages, it is one of the open problems which is not sloved analytically or numerically yet. After decompose the closed-loop system into feedback form, by adopting the small gain theorem, we obtain a sufficient condition for stabilization and a sufficient condition for It control expressed as linear matrix inequalites. Finally, we show the usefulness of our results by a numerical example.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.2
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• pp.48-56
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• 1995

The operating characteristics, such as, the threshold gain, lasing frequency, and longitudinal intensity profile, etc., of 1.55$\mu$m DFB laser diode with index and/or gain grating structures and with one side AR-coated mirror have been analyzed. From this analysis, the optimum design parameters have been shown that ${\Delta}{\Omega}$ (the phase difference between index grating and gain grating) is 0 or ${\pi}$, (xL)$_{r}$=1~3 and (xL)$_{i}$=0.5~0.9. It has been also shown that the modal selectivity and intensity uniformity of the DFB lasers with .DELTA..OMEGA.=0 are ~1.2 times better thatn those of the DFB lasers with ${\Delta}{\Omega}$= ${\pi}$.

• Proceedings of the IEEK Conference
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• summer
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• pp.218-220
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• 2004

A new wide-band VCO topology using Miller capacitance is proposed. Contrary to conventional VCO using the Miller capacitance where the variable amplifier gain is negative, the proposed VCO uses both the negative and positive variable amplifier gain to enhance the frequency tuning range significantly. The proposed VCO is simulated using HSPICE. The simulations show that 410MHz and 220MHz frequency tuning range are obtained using the negative .and positive variable amplifier gain, respectively. The tuning range of the proposed VCO is $23\%$ of the center frequency(2.8GHz). The phase noise is -104dBc/Hz at 1MHz offset by simple model. The operating current is only 3.84mA at 2.5V power supply.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.37 no.2
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• pp.83-90
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• 2000

A simple low-cost and small size 1.88-198 GHz Band RF power amplifier module is developed for IMT2000 repeater. The power amplifier consists of two stage amplifiers that the first stage amplifier is drive amplifier using discrete type P-HEMT (ATF-34143, 800 micron gate width, Agilent Technologies) and the second is power amplifier with 300Bm 1dB gain compression point using GaAs FET(EFA240D-SOT89, 2400 micron gate width, Excelics Semiconductor). this power amplifier module feature a 29.5dBm 1dB gain compression point, 29.5dB gain, 42dBm 3rd order intercept point(OIP3) and -10dB/-l2dB input/output return loss over the 1880-1980 MHz. This PA module is fully integrated using MIC technology into a small size and design by full nonlinear design technologies. The dimensions of this PA module are 42(L) $\times$ 34(W) mm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.10
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• pp.1855-1861
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• 2017

In this paper, the gain enhancement of an SDPA using a director and two parasitic patches is studied. The modified balun is used to increase the bandwidth, whereas the director and two parasitic patches are appended to the SDPA to enhance the gain in the middle and high frequency bands. The effects of the distance between the director and parasitic patches on the antenna performance are analyzed, and the SDPA with a gain over 7 dBi at 1.54-2.99 GHz band is designed. The proposed SDPA is fabricated on an FR4 substrate with a dimension of $90mm(L){\times}135mm(W)$ in order to validate its performance. The fabricated antenna shows a frequency band of 1.56-3.10 GHz for a VSWR < 2, and it is confirmed by measurement that gain maintains over 7 dBi in the frequency range of 1.54-3.00 GHz.

• The KIPS Transactions:PartC
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• v.11C no.6 s.95
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• pp.835-842
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• 2004

In this paper, we have analyzed the MC-DS/CDMA system with input signal synchronized completely through adjustment of the gain in the PLL loop, by using the hybrid SC/MRC-(2/3) technique, which is said to one of the optimal diversity techniques under the multi-path fading environment, assuming that phase error is defined to the phase difference between the received signal from the multi-path and the reference signal in the PLL of the receiver. Also, assuming that the regarded radio channel model for the mobile communication is subject to the Nakagami-m fading channel, we have developed the expressions and performed the simulation under the consideration of various factor, in the MC/DS-CDMA system with the hybrid SC.MRC-(2/3) diversity method, such as the Nakagami fading index(m), $the\;number\;of\;paths\;(L_p),$ the number of hybrid SC.MRC-(2/3) $diversity\;branches\;(L,\;L_c),$ the number of users (K), the number of subcarriers (U), and the gain in the PLL loop. As a result of the simulation, it has been confirmed that the performance improvement of the system can be achieved by adjusting properly the PLL loop in order for the MC/DS-CDMA system with the hybrid SC/MRC-(2/3) diversity method to receive a fully synchronized signal. And the value of the gain in the PLL loop should exceed 7dB in order for the system to receive the signal with prefect synchronization, even though there might be a slight difference according to the values of the fading index and the spread processing gain of the subcarrier.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.3
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• pp.461-466
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• 2019

In this paper, we have studied the improvement of gain and bandwidth characteristics by using double feeding and L-shaped inset feed line matching circuit in microstrip stacked patch antenna which is widely used to broaden the gain of general microstrip antenna. The proposed structure is composed of two feeding edges of the main patch antenna, each of them are connected to a feeding line having an L shaped inset feeder. And the parasitic patch is placed at a proper distance above the main patch. The size of the main patch is designed so that the resonance frequency is close to the center frequency of the target frequency band. The experimental results show that the bandwidth was increased more than 180MHz in the 2.3-2.7 GHz band, which is more interesting than the single feed, and the gain improvement of 2.5dBi was obtained at 2.7GHz.

• Journal of Positioning, Navigation, and Timing
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• v.12 no.2
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• pp.101-111
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• 2023

Many spoofing detection studies have been conducted to cope with the most difficult types of deception among various disturbances of GPS, such as jamming, spoofing, and meaconing. In this paper, we propose a spoofing detection scheme based on elevation masked-relative received power between GPS L1 and L2 signals in a system using a multi-band array antenna. The proposed scheme focuses on enabling spoofing to be normally detected and minimizes the possibility of false detection in an environment where false alarms may occur due to pattern distortion among elements of an array antenna. The pattern distortion weakens the GPS signal strength at low elevation. It becomes confusing to detect a spoofing signal based on the relative power difference between GPS L1 and L2, especially when GPS L2 has weak signal strength. We propose design parameters for the relative power threshold including beamforming gain, the minimum received power difference between L1 and L2, and the patch antenna gain difference between L1 and L2. In addition, in order to eliminate the weak signal strength of GPS L2 in the spoofing detection process, we propose a rotation matrix that sets the elevation mask based on platform coordinates. Array antennas generally do not have high usefulness in commercial areas where receivers are operated alone, but are considered essential in military areas where GPS receivers are used together with signal processing for beamforming in the direction of GPS satellites. Through laboratory and live sky tests using the device under test, the proposed scheme with an elevation mask detects spoofing signals well and reduces the probability of false detection relative to that without the elevation mask.