• Animal Bioscience
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• v.36 no.2
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• pp.248-255
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• 2023

Objective: Stress factors such as high temperatures, overcrowding, and diurnal temperature range exert profound negative effects on weight gain and productivity of broiler chickens. The potential of gamma aminobutyric acid (GABA) as an excitatory neurotransmitter was evaluated under various stress conditions in this study. Methods: The experiment was conducted under four different environmental conditions: normal, high temperature, overcrowded, and in an overcrowded-diurnal temperature range. The experimental groups were divided into (-) control group without stress, (+) control group with stress, and G50 group (GABA 50 mg/kg) with stress. Weight gain, feed intake, and feed conversion ratio were measured, and stress reduction was evaluated through hematologic analysis. Results: The effects of GABA on broilers in four experimental treatments were evaluated. GABA treated responded to environmental stress and improved productivity in all the experimental treatments. The magnitude of stress observed was highest at high temperature, followed by the overcrowded environment, and was least for the overcrowded-diurnal temperature range. Conclusion: Various stress factors in livestock rearing environment can reduce productivity and increase disease incidence and mortality rate. To address these challenges, GABA, an inhibitory neurotransmitter, was shown to reduce stress caused due to various environmental conditions and improve productivity.

• Korean Journal of Organic Agriculture
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• v.12 no.1
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• pp.81-92
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• 2004

The effect of feeding extracts from rhus trees on performance of broiler were performed to investigate development of natural antibiotic in process of broilers production. A total of 320 broiler chicks at 7 day of age were fed the commercial diet and water, water containing 0 ppm (control), 300 ppm (T1), 600 ppm (T2) and 1000 ppm (T3) of extracts from rims trees for 7 weeks. The body weight gain and feed conversion ratio were improvement by feeding extracts from rims trees at 7 to 21 days of age (P<0.05), but amount of feed intake and mortality were not different among the four group. When 21 to 35 days of age, body weight gain, amount of feed intake, feed conversion ratio and mortality were almost same results when 7 to 21days of age, but it was not significantly different. When 35 to 49 days of age, body weight gain in T1 and T3 group was significantly improvement than control group (P<0.05), also feed conversion ratio was improve by feeding extracts from rhus trees. There was a decrease in the microflora population of both E coli. and salmonella in the cecum contents and feaces in broilers by feeding extracts from rhus trees. Emission of ammonia and VFA gas from excreta were significantly decreased at 5 to 10 days of storaged period (P<0.05). The digestibility of dry matter, crude fat, and crude ash of feed were tend to increased in broiler feeding extracts from rims trees. Digestibility of crude protein of feed in broiler three treatmental groups was significantly improved (P<0.05) as compared with those in control group. These results indicated that the feeding extracts from rhus trees of 300 to 1000 ppm of broiler production were improvement in th6 body weight gain, feed conversion ratio, and mortality due to increasing nutrients digestibility from feed, decreasing of microflora population of both E coll. and salmonella in the cecum contents and feaces, decreasing emission of ammonia and VFA gas from excreta.

• Animal Bioscience
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• v.36 no.4
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• pp.601-608
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• 2023

Objective: This study was conducted to investigate the effects of energy and protein levels in the diet of Hanwoo heifers on growth response and animal behavior. Methods: Forty heifers were randomly allocated into three experimental groups according to the target daily weight gain in 8 pens (T-0.2, 2 replications; T-0.4 and -0.6, 3 replications) based on similar body weight (BW) and age in months. The target average daily gain (ADG) was set at 0.2 (T-0.2), 0.4 (T-0.4), and 0.6 kg/d (T-0.6), and feed was based on National Institute of Animal Science (NIAS, 2017). In order to minimize hunger stress of T-0.2 and -0.4, the feeding ratio of rice straw was set to 55%, 50%, and 45% for T-0.2, -0.4 and T-0.6, respectively, so that the dry matter (DM) intake for all treatment groups was uniform but the energy and protein levels in the diet were adjusted differently. A total of 6 items (lying, standing, eating, rumination, walking and drinking) of animal behavior were analyzed. Results: During the whole period of the experiment, the ADG of the T-0.2, -0.4 and -0.6 treatments were 0.48, 0.56, and 0.65 kg/d (p<0.05), respectively, showing higher gain than the predicted value, especially for the low target ADG group. Based on these results, regression equations for the total digestible nutrient (TDN) and crude protein (CP) requirements were derived. No behavioral differences were found according to the energy and protein levels in the diet because the DM intake was kept constant by adjusting the roughage and concentration ratio. However, eating time was longer (p<0.05) at T-0.2 than T-0.6 during the whole day. Conclusion: Through this study, it was possible to derive regression equations for predicting TDN and CP requirements according to the target ADG and BW.

• KIEE International Transactions on Electrophysics and Applications
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• v.11C no.4
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• pp.99-106
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• 2001

An overview of Silicon Carbide (SiC) Static Induction Transistor (SIT) development is presented. Basic conduction mechanisms are introduced and discussed, including ohmic, exponential, and space charge limited conduction (SCLC) mechanisms. Additionally, the impact of velocity saturation and temperature effects on SCLC are reviewed. The small-signal model, breakdown voltage, power density, and different gate structures are also discussed, before a final review of published SiC SIT results. Published S-band (3-4 GHz) results include 9.5 dB of gain and output power of 120 W, and L-band (1.3 GHz) results include 400 W output power, 7.7 dB of gain, and power density of 16.7 W/cm.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.4 no.2
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• pp.39-44
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• 1998

We used recording device(EDR-3) to monitor the packages and the vehicle during shipment. Provided we did this enough times, we began to gain statistically valid information which could be used to describe the particular channel of distribution. The event was obviously changed from trip to trip, but in general we could have an idea of what to expect. Considerable amount of time and money were invested to record field data. Although not ideal, it was the best suited approach to gain information regarding a specific distribution channel. Based on the recorded field data, we could make our own packaging vibration testing specification through MIL-STD-810D(Guidance for development of laboratory dynamic test specification). This test specification was proved several times through field tests. As a result, we gained confidence in this revised vibration specification and come to know the development procedures of a laboratory dynamic test specification.

• Journal of the Korean Operations Research and Management Science Society
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• v.18 no.2
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• pp.183-203
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• 1993

One of the most difficult and time-consuming stages in the development of the knowledge-based system is a knowledge acquisition. A splitting algorithm is developed to infer a rule-tree which can be converted to a rule-typed knowledge. A market segmentation may be performed in order to establish market strategy suitable to each market segment. As the sales data of a product market is probabilistic and noisy, it becomes necessary to prune the rule-tree-at an acceptable level while generating a rule-tree. A splitting algorithm is developed using the pruning measure based on a total amount of information gain and the measure of existing algorithms. A user can easily adjust the size of the resulting rule-tree according to his(her) preferences and problem domains. The algorithm is applied to a market segmentation problem of a medium-large computer market. The algorithm is illustrated step by step with a sales data of a computer market and is analyzed.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.1
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• pp.50-56
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• 2014

In this paper, we proposed a Ku-band antenna that can be mounted on UAV. A proposed antenna structure has small size and light weight. It is considered long distance communication environment(LOS) and equipped UAV. Proposed antenna is designed $16{\times}2$ aperture coupled microstrip patch array antenna for high gain characteristics. In the measurement results, VSWR is less than 1.5 and the gain is over 21dBi in the bandwidth. Mechanical specifications of antenna assembly are ${\phi}250{\times}200mm$ of size and 3kg of weight.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.4
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• pp.537-543
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• 2014

RLG(Ring Laser Gyroscope) is a main device of LINS(Laser Inertial Navigation System). RLG has the lock-in region in which there is no output signal. To alleviate the lock-in problem, a mechanical oscillation, the dither motion, is applied on RLG. A LPF(Low Pass Filter) is usually used on the output of RLG and accelerometer to remove the noise that is made by the dither motion. When the LINS is induced the disturbance during the initial alignment, it takes more time on alignment due to the use of the LPF and a fixed gain controller. In this paper, an initial alignment using UKF(Unscented Kalman Filter) is designed and analysed. Analysis include comparison between conventional initial alignment loop using fixed gain type controller and proposed initial alignment using UKF. Moreover, Disturbance inducing test results are demonstrated.

• Korean Journal of Agricultural Science
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• v.48 no.3
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• pp.447-454
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• 2021

This study was conducted to evaluate the effects of different copper sources (inorganic and organic) on the growth performance, fecal copper excretion, intestinal morphology, and health in growing pigs. A total of 40 growing pigs (30.22 ± 1.92 kg) were randomly assigned to 5 dietary treatments: a basal control diet (CON), 4 experimental diets supplemented with either copper sulfate (CuSO₄), Cu-glycine complex (CuGly), Cu-amino acid complex (CuAA), or Cu-hydroxy-4-methylthio butanoate chelate complex (CuHMB) at 100 ppm, respectively. At the end of the study (28 days), fecal and blood samples were collected, and the pigs were slaughtered to determine the intestinal morphology. During the 28 days of the experimental period, pigs fed the inorganic and organic copper showed a higher average daily gain (p < 0.01) and gain feed ratio (p < 0.01). There were no differences in mineral concentrations of the serum; however, the copper concentration of the feces was lower (p < 0.01) in the CuAA and CuHMB groups. The intestinal morphology and blood profiles did not significantly differ between the groups. In conclusion, the organic copper sources (CuAA and CuHMB) can be used as a growth promoter to replace the CuSO₄ without any negative effects on health in growing pigs and to reduce fecal copper excretion.

• Asian-Australasian Journal of Animal Sciences
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• v.8 no.3
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• pp.289-293
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• 1995

The experiment was conducted to study the effect of supplementary urea molasses block lick with rice straw based diet on the performance of sheep. Six indigenous sheep of about two years of age with an average body weight of 12.88 kg, were selected for this experiment They grouped into two by stratified randomization, and the experiment was conducted for a period of 90 days. Sheep of group A was fed rice straw and group B was feed rice straw with urea molasses block lick, beside this both the groups received 66 g wheat bran and 167 g of Ipil-Ipil leaf meat. The study revealed that the average daily gain of live weight per sheep per day was 41 gm and 70 gm in group-A and group-B respectively. From the analysis of variance it was evident that live weight gain in sheep of group B, supplemented with urea molasses block lick was highly significant (p < 0.01). It was also estimated that group A required 8.12 kg DM to gain 1 kg live weight, whereas group B receiving urea molasses block lick required 5.30 kg DM to gain 1 kg live weight. Therefore, feeding rice straw with urea molasses block lick able to utilize more crop-residues efficiently.