• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.11
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• pp.1471-1476
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• 2018

In this paper, a high-gain antenna for satellite communication is proposed. The proposed antenna consists of septum polarizer, circular waveguide, Hat-feed structure that has a high-gain and efficiency. Especially, it is smaller and lighter than the conventional satellite communication antennas by applying a hat-feed structure. The measured results show that received gain of proposed antenna is better than 29.9 dBi and transmitted gain of proposed antenna is better than 30.5 dBi. The co-polarized and cross-polarized radiation patterns comply with ITU-RR Ap.8 and ITU-R S.731-1 that are recommended by International Telecommunication Union. The designed high-gain antenna for satellite communication is expected to be used for OTM and airborne satellite systems.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.7
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• pp.19-26
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• 2018

This study tested 25 lightweight aggregate concrete (LWAC) mixtures using the expanded bottom ash and dredged soil granules to examine the compressive strength gain of such concrete with different ages. The test parameters investigated were water-to-cement ratios and the natural sand content for the replacement of lightweight fine aggregate. The compressive strength gain rate in the basic equation specified in fib model code was experimentally determined in each mixture and then empirically formulated as a function of the water-to-cement ratio and oven-dried density of concrete. When compared with 28-day compressive strength, the tested LWAC mixtures exhibited relatively low gain ratios (0.49~0.82) at an age of 3 days whereas the gain ratios (1.16~1.41) at 91 days were higher than that (1.05~1.15) of the conventional normal-weight concrete. Thus, the fib model equations tend to overestimate the early strength gain of LWAC but underestimate the long-term strength gain. The proposed equations are in good agreement with the measured compressive strength development of LWAC at different ages, indicating that the mean and standard deviation of the normalized root mean square errors determined in each mixture are 0.101 and 0.053, respectively.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.1
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• pp.90-97
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• 2017

In this paper, we propose a new array antenna scheme which has an improved side lobe level (SLL) as well as a simplified feeding network and a high gain. The proposed array scheme is based on a non-uniformly excited sub-array. For analysis, we use an array factor of sub-array antenna. In the simulation results, the simulated SLL and gain provide more than 18.43 dB and 26.63 dBi, respectively. For the verification of the proposed design scheme, the prototype antenna with $16{\times}8$ radiating elements was designed by the proposed array scheme. The measured SLL and gain are more than 19.85 dB and 25.53 dBi, respectively. This measurement result indicates that the proposed array scheme is reasonable.

• Journal of Electrical Engineering and Technology
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• v.4 no.3
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• pp.401-404
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• 2009

A simple analytical expression for a current gain of IGBT is derived in terms of the device parameters as well as a gate length dependent parameter, which allows for the determination of the current components of the device as a function of its gate length. The analytical results are compared with those from simulation results. A good agreement is found.

• Journal of Animal Science and Technology
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• v.62 no.2
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• pp.247-262
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• 2020

Birth weight and subsequent weight gain is of critical importance in the survival and performance of piglets on a commercial swine farm setting. Oropharyngeal microbiome could influence immunity, and feeding behavior thus impacting health and weight gain. We used 16S rRNA gene sequencing to profile the composition and predicted metabolic functionality of the oropharyngeal microbiota in 8 piglets (4 with a birthweight ≤ 1.0 kg and 4 with a birthweight ≥ 1.7 kg) at 11, 26, and 63 days of age. We found 9 genera that were significantly associated with average daily gain (ADG) at 11 days (false discovery rate, FDR < 0.05) and 26 days of age (FDR < 0.1), respectively. The microbial functional profile revealed several pathways associated with ADG (FDR < 0.05). Among these, pathways related to degradation of catechols showed a positive association with ADG at 11, 26, and 63 days of age, implying a potential to breakdown the host-derived catecholamines. We also noted that pathways related to the biodegradation of nucleosides and nucleotides increased with ADG during the pre-weaning phase, while those involved in their biosynthesis decreased. Our findings provide insights into the oropharyngeal microbial memberships and metabolic pathways that are involved in a piglet's weight gain. Thus, providing a basis for the development of strategies aimed at improving weight gain in pigs.

• Journal of the Korean Institute of Intelligent Systems
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• v.9 no.4
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• pp.384-388
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• 1999

This paper describes an approach for synthesizing a modularized gain scheduled PD type fuzzy logic controller(FLC) of nonlinear magnetic bearing system where the gains of FLC are on-line adapted according to the operating point. Specifically the systematic procedure via root locus technique is carried out for the selection of the gains of FLC. Simulation results demonstrate that the proposed gain scheduled fuzzy logic controller yields not only maximization of stability boundary but also better control performance than a single operating point (without gain scheduling)fuzzy controller.

• The Journal of the Korea Contents Association
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• v.7 no.8
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• pp.199-206
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• 2007

Capital gain comes from the transfer gain which is occurring by transferring assets except inventory assets. Our government recently has made capital gain tax on real estates and imposed as classified income tax by including it into aggregate income so that provide function of tax and curb property speculation. However the present income tax law imposes capital gain tax on capital profit including real estate and securities, while this law and the special tax treatment control law implement non-taxation and tax exemption too widely. That is to say, the system of capital gain tax can hinder the fair tax because it has various exemption terms including the non-taxation principle on a house for a family and the special tax treatment law. And also it has a problem in the sense of equity because it imposes tax by progressive tax rate on the subjects of capital gain tax considering them as the profit of that year, which were transferred, so there is difference between the income which has been made for a long time and the income made for a short time even in the same capital gain. Therefore this study identifies some issues surrounding the present capital gain tax system and focuses on presenting reasonable development plan.

• Journal of the Optical Society of Korea
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• v.16 no.1
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• pp.53-56
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• 2012

We have developed a slab-type Nd:YAG gain module based on the techniques of conduction cooling and end pumping. The Nd:YAG slab is end-capped on both ends by undoped pure YAG and is pumped through the end-caps by stacked arrays of laser diode bars. The slab's surfaces of total internal reflection are in contact on both sides with microchannel cooling blocks which are cooled by water circulation. The power oscillator based on the gain module generates more than 400 W at 1-kW pumping with a slope efficiency of 55%. The small-signal gain of the gain module is 10 in a single zig-zag pass, and the amplified beam shows a near diffraction-limited beam quality.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.2
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• pp.10-20
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• 1997

This paper describes the design, the manufacture and the development of th eautomatic gain control unit which ajdusts the gain of IF processor in the high sensitive & multifunctional receiver unit (HMR) for pulse doppler radar system. Accodording to the effective distnce of target, radar cross section, and a lot of external environments (such as clutter), the receiving stage of RADAR system often deviates from dynamic range. To solve this kind o fproblem, continuous/pulse wave AGC are realized, make it possible to control the gain characteristics of receiver stably, and can increase dynamic range linearly by adjusting the gain slope of receiver which is limited by 1-dB gain compression point. In this study, AGC unit is designed to regulate the total gain of receiver by using te analog feedback theory. It also has rapid enough response to process pulse signal. This study presents the gain control method of IF, the real manufacture technique (the package-type components) and the measurement performance of AGC.

• Journal of the Korea Institute of Military Science and Technology
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• v.23 no.1
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• pp.11-17
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• 2020

This study proposes a novel structure for the cross-eye, one of the representative jamming techniques of monopulse sensors. The proposed jammer tranceivers are composed of multi-channels with phased array antenna. We named this structure PRCJ(Phased array Retrodicetive Cross-eye Jammer). In this structure, formulas for calculating cross-eye gain and distance error are derived. We compare the properties of PRCJ with two-element retrodiredtive cross-eye jammer(TRCJ). PRCJ can achieve higher J/S because this structure can steer the spatially combined jamming signal in the direction of the incident monopulse signal. Because of the multiple channels in the phased array, it also increases the degree of freedom of channel matching. Finally, We preform a statistical analysis of the cross-eye gain according to the amplitude and phase errors. From this results, It has been found that PRCJ can get higher cross-eye gain than TRCJ.