• Journal of Satellite, Information and Communications
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• v.12 no.2
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• pp.83-88
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• 2017

In this paper, we propose a three-element CRPA array with improved low-elevation gain. The proposed antenna consists of a feed patch and a radiating patch, and the feed patch is connected by a coaxial cable. The radiating patch is electromagnetically coupled to the feed patch, which allows to improve the low-elevation gain of the antenna. To demonstrate the suitability of the proposed antenna, the antenna characteristics are measured in a full anechoic chamber. The resulting bore-sight gain is 2.8 dBic with an axial ratio of 2.7 dB, and the average gain at the low-elevation direction of $75^{\circ}$ is -1.4 dBic. The results verify that the proposed antenna is suitable for CRPA arrays with anti-jamming capability.

• Journal of Korean Biological Nursing Science
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• v.21 no.3
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• pp.169-177
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• 2019

Purpose: The purpose of this paper was to identify blood pressure, interdialytic weight gain, thirst and intradialytic discomfort in subjects after applying individual low-sodium dialysis fluid (1,2,3 mEq/L) to hemodialysis patients for 12 weeks. Methods: This study was a non-equivalent pre-post design. For 12 weeks, dialysate concentration was maintained at 1 mEq/L or 2 mEq/L or 3 mEq/L based on average sodium concentration of each individual, and the difference was compared after applying individually. Results: Change in blood pressure significantly decreased in the group where in pre-hemodialysis systolic pressure decreased the gradient of sodium concentration in serum sodium and dialysis solution by 2mEq/L. Interdialytic weight gain, and thirst showed significant decrease in all three groups. But in all three groups, intradialytic discomfort among dialysis showed no significant changes. Conclusion: Although application of low sodium dialysis fluid showed no change in intradialytic discomfort, lowered blood pressure, thirst, and interdialytic weight gain, which could be used for individual showing increased interdialytic weight gain and increased blood pressure. There is need for continued study on this.

• 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.

• The Journal of Korea Robotics Society
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• v.17 no.2
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• pp.221-229
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• 2022

Sliding mode control (SMC) is a robust control method to control a robot arm with nonlinear properties. A high switching gain of SMC causes chattering problems, although the SMC allows the adequate control performance by giving high switching gain, without the exact robot model containing nonlinear and uncertainty terms. In order to solve this problem, SMC with sliding perturbation observer (SMCSPO) has been researched, where the method can reduce the chattering by compensating the perturbation, which is estimated by the observer, and then choosing a lower switching control gain of SMC. However, optimal gain tuning is necessary to get a better tracking performance and reducing a chattering. This paper proposes a method that the Q-learning automatically tunes the control gains of SMCSPO with an iterative operation. In this tuning method, the rewards of reinforcement learning (RL) are set minus tracking errors of states, and the action of RL is a change of control gain to maximize rewards whenever the iteration number of movements increases. The simple motion test for a 7-DOF robot arm was simulated in MATLAB program to prove this RL tuning algorithm. The simulation showed that this method can automatically tune the control gains for SMCSPO.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.5
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• pp.23-30
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• 2000

To compensate the nonlinearity of electroabsorption modulator(EAM) resulting from its near exponential transfer function, a semiconductor optical amplifier(SOA) that has a log transfer function is used. Since the transfer function of SOA is inverse to that of EAM, the intermodulation distortion(IMD) of EAM can be reduced by cascading SOA to EAM. Also, the RF gain can be increased by the optical gain of SOA. For these reasons, spurious free dynamic range(SFDR) of EAM is enhanced by connecting SOA to EAM in series and operating in gain salutation region. To improve the nonlinearity compensation of EAM, the increased gain of SOA is required and the slope of gain saturation, the ratio of gain to input SOA power, needs to be steep. However, signal spontaneous beat noise that is the dominant system noise increases in proportion to the gain such that the SFDR of EAM is reduced. The higher the gain of SOA is, the more ASE is increased. Thus the noise level of system is increased and the following SFDR of EAM is decreased. The slope of gain saturation region and ASE of have trade-off relation and the optimization is achieved at 8㏈ optical gain. 9㏈ enhancement of SFDR of EAM is obtained. This scheme is easy to embody the linear EAM and the integration with three components (DFB-LD, EAM and SOA) offers many merits, such as low insertion loss, low chirping and low polarization sensitivity.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.4
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• pp.9-16
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• 2013

Long term evolution (LTE) and LTE-Advanced (LTE-A) systems adopt closed-loop multiple-input multiple-output antenna techniques. Equal gain transmission which has equal gain property is the key factor in their codebook design. In this paper, a novel differential codebook structure which maintains the codebook design requirements of LTE or LTE-A systems. Especially, eight-phase shift keying (8-PSK) constellations are used as elements of codewords, which not only maintain equal gain property but also reduce the computation complexity of precoding and decoding function blocks. The equal gain property is very important to uplink because the performance of uplink is very sensitive to the peak-to-average power ratio (PAPR). Moreover, the operation of the proposed differential codebook is explained as a rotation-lock structure. As the results of computer simulations, the steady-state throughput performance of the proposed codebook shows at least 0.9dB of SNR better than those of the conventional LTE codebook with the same amount of feedback information.

• Korean Journal of Poultry Science
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• v.21 no.2
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• pp.83-92
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• 1994

In order to study performance enhancing effects of supplementary antibiotics (avoparcin, nosiheptide and enramycin), two feeding trials were conducted. In Experiment 1, 1, 040 male Arbor Acres were reared in floor pens for 6 wk. Chicks were assigned to one of the following four treatments: Basal diet(B), B+avoparcin 10 ppm, B+nosiheptide 2.5 ppm and B+enramycin 5 ppm. Each treatment had five replications of 52 chicks each. In Experiment 2, two antibiotics (avoparcin and enramycin) were compared in $2{\times}2$ (antibiotics$\times$sex) factorial design. One thousand broiler chicks were reared in floor pens for 6 wk. Each of the 4 treatments had five replications of 50 chicks each. The results of Experiment 1 showed that antibiotic treatments (enramycin, avoparcin and nosiheptide) significantly(P <0.05) improved weight gain. Feed/gain ratio of avoparcin treatment and enramycin treatment tended to he lower than the control but they were not statistically significant. Dressing percentages were high in avoparcin and enramycin treatments compared to the control and nosiheptide treatment. The number of E. coli and Cl. perfringens in ileum and cecal contents were decreased by antibiotic treatments. Moisture contents in excreta of the birds were not significantly affected by the treatments. Leg abnormality and mortality were not significaniy different among treatments. In Experiment 2, weight gain was significantly (P<0.01) different between sexes, but not between antibiotic treatments. Significant effects of antibiotics (P<0.01), sex (P<0.01) and interaction (P<0.05) were shown in feed in take. Feed/gain ratio of avoparcin treatment was significantly (P<0.01) lower than that of enramycin treatment. leg abnormality and mortality were not significantly different among treatments but those in male broiler tended to be higher than in female broilers. It was concluded that nonsystemic antibiotics supplemented to the broiler diets suppress undesirable microorganisms and improve broiler performace in general and avoparcin was most effective in improving feed/gain ratio.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.5 no.2
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• pp.61-67
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• 2012

In this paper, In this paper, we consider a dynamic range in the frequency converter to obtain a high conversion gain and linearity while operating area proposed to broaden the design. Super-heterodyne RF Front-End style was applied to the active mixer stage, GaAs devices were used. Circuit design easy and simple forms benefit circuit is constructed in the drain mixer, passive mixer with the operating area were compared and analyzed. The simulation results of the conversion gain of 2.4dB and 0.2dBm about a gain-compression point, and showed the dynamic range of 71.9dB, when compared with passive mixers, dynamic range of approximately 6dB improvement was identified. Measurements of an approximately 2dB conversion gain and-1.0dBm of the gain-compression point, and confirmed that the active area of 71.1dB. When compared with passive mixers, dynamic range of is reduced by approximately 8dB has been improved.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.9
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• pp.1305-1309
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• 2005

Experiments were conducted to determine the efficacy of modified montmorillonite nanocomposite (MMN) to reduce the toxic effects of aflatoxin (AF) in growing/finishing pigs. 96 weaned pigs were assigned to four dietary treatment groups (0 g of MMN and 0 mg of AF/kg feed, 3 g of MMN/kg feed, 0.1 mg of AF/kg feed, and 3 g of MMN plus 0.1 mg of AF/kg feed). Body weight gain (BW gain), feed/gain ratio, serum biochemical values and enzyme activities were evaluated. Compared with the control, AF alone markedly reduced BW gain and resulted in a significantly higher feed/gain ratio. There were no differences in BW gain and feed/gain ratio between 0.3% MMN or 0.3% MMN plus AF and the control. These results suggested that the deleterious effects of AF were ameliorated by MMN addition. AF intake markedly increased relative organ weights of liver, kidney, spleen and pancreas, and resulted in significant alterations of serum parameters. However, these parameters for pigs fed diets containing MMN and AF returned to normal values, indicating that MMN had the ability to recover the AF-decreased performance, organ damage and to correct aberrations in serum parameters. These findings in our study suggested that MMN can effectively modulate the toxicity of AF in growing/finishing pigs and may offer a novel approach to the preventive management of aflatoxicosis in animals.

• YAKHAK HOEJI
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• v.52 no.4
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• pp.288-292
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• 2008

Olanzapine, an atypical antipsychotic, has been widely used for the treatment of schizophrenia and bipolar disease. Although olanzapine is less associated with extrapyramidal symptoms and neuroleptic malignant syndrome compared to existing typical antipsychotics, the use of this drug has a problematic side effect of weight gain, which may cause metabolic syndrome such as type 2 diabetes. However, there are few hospitals practicing body weight monitoring of the patients on olanzapine or other atypical antipsychotics. The goal of this study was to identify the incidence and severity of weight gain associated with the use of the drug in Korea. We performed body weight monitoring of the patients who were on the drug in a hospital setting. Mean of the weight gain (as of one-month-transformation) was 4.33 and 3.39 kg for the male and female patients, respectively. The incidence in the young patients was higher than that observed in the old patients, and the severity was the highest in patients in their thirties followed by twenties or younger. This result suggests that the pattern of the weight gain associated with the use of olanzapine in Korea is similar to the reports performed and documented in US and European countries. Therefore, it appears that healthcare professionals in Korea should also watch on the weight gain issue in patients who are on olanzapine or other atypical antipsychotics.