• Journal of the Korean Solar Energy Society
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• v.23 no.2
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• pp.91-98
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• 2003

Experimental study for a porous aluminum heat dissipator/or heat sink made by casting method is conducted to evaluate the performance of the porous aluminum heat sinks. The parameters applied for the present study are the manufacturing method. various bonding materials for the bottom plate of heat sink, and their different material, pore size, etc.. The casting method for porous aluminum heat sink is suggested for the best performance of heat dissipation in this experiment. The bottom plate applied by melting aluminum is introduced and proved their excellent characteristics compared with brazing, soldering, and bonding methods. In the present experiment, aluminum with different conductivities, such as AC8A and pure aluminum, are tested and the pure aluminums with the higher conductivity than AC8A shows their improvement of the performance. And the proper dimensions related to the pore size and the height of porous aluminum heat sinks are proposed in the present study.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.445-447
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• 2016

SQLite, Realm, etc. are database engines which are suitable for small devices that have large resource restriction and are used a lot in mobile devices based on Linux. These engines are open source programs and have advantages which are lighter weight and faster speed than general purpose databases. This paper implements performance test program and performs performance experiment of SQLite database to test search efficiency in Linux environments. The experiment is processed by comparison with the results of a Oracle database working out at the same environment.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.1
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• pp.57-63
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• 2017

Objective: Two experiments were conducted to determine the effects of adding exogenous phytase and xylanase, individually or in combination, as well as pelleting on nutrient digestibility, available energy content of wheat and the performance of growing pigs fed wheat-based diets. Methods: In Experiment 1, forty-eight barrows with an initial body weight of $35.9{\pm}0.6kg$ were randomly assigned to a $2{\times}4$ factorial experiment with the main effects being feed form (pellet vs meal) and enzyme supplementation (none, 10,000 U/kg phytase, 4,000 U/kg xylanase or 10,000 U/kg phytase plus 4,000 U/kg xylanase). The basal diet contained 97.8% wheat. Pigs were placed in metabolic cages for a 7-d adaptation period followed by a 5-d total collection of feces and urine. Nutrient digestibility and available energy content were determined. Experiment 2 was conducted to evaluate the effects of pelleting and enzymes on performance of wheat for growing pigs. In this experiment, 180 growing pigs ($35.2{\pm}9.0kg\;BW$) were allocated to 1 of 6 treatments according to a $2{\times}3$ factorial treatment arrangement with the main effects being feed form (meal vs pellet) and enzyme supplementation (0, 2,500 or 5,000 U/kg xylanase). Results: In Experiment 1, there were no interactions between feed form and enzyme supplementation. Pelleting reduced the digestibility of acid detergent fiber (ADF) by 6.4 percentage units (p<0.01), increased the digestibility of energy by 0.6 percentage units (p<0.05), and tended to improve the digestibility of crude protein by 0.5 percentage units (p = 0.07) compared with diets in mash form. The addition of phytase improved the digestibility of phosphorus (p<0.01) and calcium (p<0.01) by 6.9 and 7.6 percentage units respectively compared with control group. Adding xylanase tended to increase the digestibility of crude protein by 1.0 percentage units (p = 0.09) and increased the digestibility of neutral detergent fiber (NDF) (p<0.01) compared with control group. Supplementation of the xylanase-phytase combination improved the digestibility of phosphorus (p<0.01) but impaired NDF digestibility (p<0.05) compared with adding xylanase alone. In Experiment 2, adding xylanase increased average daily gain (p<0.01) and linearly improved the feed:gain ratio (p<0.01) compared with control group. Conclusion: Pelleting improved energy digestibility but decreased ADF digestibility. Adding xylanase increased crude protein digestibility and pig performance. Phytase increased the apparent total tract digestibility of phosphorus and calcium. The combination of phytase-xylanase supplementation impaired the effects of xylanase on NDF digestibility.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.4
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• pp.563-567
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• 2006

Two experiments were conducted to compare the effect of various vitamins on performance and digestibility in growing pigs. In experiment 1, a total of 54 pigs ($L{\times}Y{\times}D$, $42.73{\pm}2.40kg$) were assigned to three treatments in a randomized complete block design with three replicates (6 pigs/pen) for 40 days. The three dietary treatments were: 100% fat-soluble vitamins (FSV) and water-soluble vitamins (WSV); 150% FSV and 100% WSV of NRC (1998); and 100% FSV and 150% WSV of NRC (1998). In experiment 2, a total of 180 pigs ($L{\times}Y{\times}D$, $28.20{\pm}3.05 kg$) were assigned to four treatments in a completely randomized design with three replicates for four weeks (15 pigs/pen). The four dietary treatments were, 150% vitamin A and 100% other vitamins, 150% vitamin D and 100% other vitamins, 150% vitamin E and 100% other vitamins, and 150% vitamin K and 100% other vitamins. In experiment 1, there were significant differences in growth performance and digestibility of nutrients among the treatments. The ADG, ADFI and FCR of pigs fed 150% FSV diet were better (p<0.05) than those fed the control diet. However, there were no differences (p>0.05) in ADG, ADFI and FCR between pigs fed the control and 150% WSV diets. Digestibilities of dry matter, gross energy and calcium were improved in 150% FSV treatment group compared with control (p<0.05). However, the improvement was similar when compared with 150% WSV except for Ca. In experiment 2, there were no differences (p>0.05) in ADG, ADFI and FCR and nutrient digestibility between the fat-soluble vitamin treatments when fed at the 150% level. In conclusion, growing pigs were more responsive to additional fat-soluble vitamin supplements over the requirements suggested by NRC (1998) than to water-soluble vitamin supplements as measured by growth performance and digestibility of nutrients.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.157.1-157.1
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• 2016

In this work, we experimentally investigated the solar absorption performance of Cu-based scalable nanostructured surfaces and compared their performance with the conventional TiNOX. We fabricated Cu-based nanostructured surfaces with a controlled chemical oxidation process applicable to a large area or complex geometry. We optimized the process parameters including the chemical compounds, dipping time and process temperature. We conducted both lab-scale and outdoor experiments to characterize the conversion efficiency of each absorber surfaces with single and double glazing setup. Lab-scale experiment was conducted with $50mm{\times}50mm$ absorber sample with 1-sun condition (1kW/m2) using a solar simulator (PEC-L01) with measuring the temperature at the absorber plate, cover glass, air gap and ambient. From the lab-scale experiment, we obtained ${\sim}91^{\circ}C$ and $94^{\circ}C$ for CuO and TiNOX surfaces after 1 hr of solar illumination at single glazing, respectively. To measure the absorber performance at actual operating condition, outdoor experiment was also conducted using $110mm{\times}110mm$ absorber sample. We measured the solar flux with thermopile detector (919P-040-50). From outdoor experiment, we observed ${\sim}123^{\circ}C$ and $131^{\circ}C$ for CuO and TiNOX with 0.6 kW/m2 insolation at double glazing, respectively. We showed that the suggested nanostructured CuO solar absorber has near-equivalent collection efficiency compared with the state-of-the-art TiNOX surfaces even with much simpler manufacturing process that does not require an expensive equipment.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.7
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• pp.993-1000
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• 2011

The aim of this study was to evaluate the potential of fermented red ginseng extract (FRGE) as feed additive in broilers and laying hens. In broilers, 480 Arbor Acre male broilers were randomly allotted to 4 treatments with 6 replications per treatment and 20 chicks per pen. The experiment lasted 5 weeks and dietary treatments were as follows: i) CON, basal diet; ii) FRGE1, basal diet+1 g/kg fermented red ginseng extract; iii) FRGE2, basal diet+2 g/kg fermented red ginseng extract and iv) FRGE3 basal diet+4 g/kg fermented red ginseng extract. Throughout the experiment, no effects were observed (p>0.05) in performance in response to FRGE. At the end of the experiment, FRGE administration improved (p<0.05) the lymphocyte level compared with CON. The relative weight of bursa of fabricius and spleen were increased (p<0.05) by the inclusion of FRGE3. Besides, redness ($a^*$) value for the breast meat was higher (p<0.05) in FRGE1 and FRGE3 treatments than that in CON. In laying hens, 240 ISA brown layers at 35 weeks of age were used in this 8-week trial. Dietary treatments were the same as in the broilers trial with 10 replicates per treatment and 6 layers per replicate. During the entire experiment, there were no significant differences (p>0.05) in performance or egg quality among all the treatments. However, the layers fed diets supplemented with FRGE had higher lymphocyte level (p<0.05) compared with those fed CON. In conclusion, the dietary supplementation with FRGE did not influence performance but improved the lymphocyte level in both broilers and laying hens.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.9
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• pp.1288-1295
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• 2015

In experiment 1, eighty crossbred steers ($239{\pm}15kg$) were used in a 229-d experiment to evaluate the effects of increasing levels of enzymatically hydrolyzed yeast (EHY) cell wall in diets on growth performance feedlot cattle during periods of elevated ambient temperature. Treatments consisted of steam-flaked corn-based diets supplemented to provide 0, 1, 2, or 3 g EHY/hd/d. There were no effects on growth performance during the initial 139-d period. However, from d 139 to harvest, when 24-h temperature humidity index averaged 80, EHY increased dry matter intake (DMI) (linear effect, p<0.01) and average daily gain (ADG) (linear effect, p = 0.01). There were no treatment effects (p>0.10) on carcass characteristics. In experiment 2, four Holstein steers ($292{\pm}5kg$) with cannulas in the rumen and proximal duodenum were used in a $4{\times}4$ Latin Square design experiment to evaluate treatments effects on characteristics of ruminal and total tract digestion in steers. There were no treatment effects (p>0.10) on ruminal pH, total volatile fatty acid, molar proportions of acetate, butyrate, or estimated methane production. Supplemental EHY decreased ruminal molar proportion of acetate (p = 0.08), increased molar proportion of propionate (p = 0.09), and decreased acetate:propionate molar ratio (p = 0.07) and estimated ruminal methane production (p = 0.09). It is concluded that supplemental EHY may enhance DMI and ADG of feedlot steers during periods of high ambient temperature. Supplemental EHY may also enhance ruminal fiber digestion and decrease ruminal acetate:propionate molar ratios in feedlot steers fed steam-flaked corn-based finishing diets.

• Fire Science and Engineering
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• v.23 no.4
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• pp.137-144
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• 2009

This paper was studied on the problem of field inspection tester of the photoelectric type smoke detector. The experiment objects were chosen 3 type's testers such as A type (incense), B type (dimethylpolysiloxane), C type (mixtures of hydrocarbon) which were used for performance checking of the photoelectric type smoke detector for the fire protection. The experimental methods were used reliability verification experiment, performance verification experiment and performance change of fire detector by smoke component. It was confirmed through the experiment that the testers had problems of smoke concentration condition and wind velocity condition and smoke component. Consequently, this paper verified that the field inspection testers of the photoelectric type smoke detector had problems in the inspection of fire protection.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.8
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• pp.1596-1603
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• 2007

In this paper, we experimented by three kind of method for feature parameter, training method and recognition algorithm of most suitable for speech recognition system and considered. We decided speech recognition system of most suitable through two kind of experiment after we make speech recognizer. First, we did an experiment about three kind of feature parameter to evaluate recognition performance of it in speech recognizer using existent MFCC and MFCC new feature parameter that change characteristic space using PCA and ICA. Second, we experimented recognition performance or HMM, SVM and RVM by studying data number. By an experiment until now, feature parameter by ICA showed performance improvement of average 1.5% than MFCC by high linear discrimination from characteristic space. RVM showed performance improvement of maximum 3.25% than HMM in an experiment by decrease of studying data. As such result, effective method for speech recognition system to propose in this paper derives feature parameters using ICA and un recognition using RVM.

• Journal of Ocean Engineering and Technology
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• v.36 no.5
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• pp.326-339
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• 2022

Recently, not only Korea but also the world has been suffering from problems related to coastal erosion. The hard defense method has been primarily used as a countermeasure against erosion. However, this method is expensive and has environmental implications. Hence, interest in other alternative methods, such as the eco-friendly vegetation method, is increasing. In this study, we aim to analyze the hydraulic characteristic of submerged rigid vegetation according to the cross-sectional change through a hydraulic experiment and numerical simulation. From the hydraulic experiment, the reflection coefficient, transmission coefficient, and energy dissipation coefficient were analyzed according to the density, width, and multi-row arrangement of the vegetation zone. From numerical simulations, the flow field, vorticity distribution, turbulence distribution, and wave distribution around the vegetation zone were analyzed according to the crest depth, width, density, and multi-row arrangement distance of the vegetation zone. The hydraulic experiment results suggest that the transmission coefficient decreased as the density and width of the vegetation zone increased, and the multi-row arrangement condition did not affect the hydraulic characteristics significantly. Moreover, the numerical simulations showed that as the crest depth decreased, the width and density of vegetation increased along with vorticity and turbulence intensity, resulting in increased wave height attenuation performance. Additionally, there was no significant difference in vorticity, turbulence intensity, and wave height attenuation performance based on the multi-row arrangement distance. Overall, in the case of submerged rigid vegetation, the wave energy attenuation performance increased as the density and width of the vegetation zone increased and crest depth decreased. However, the multi-row arrangement condition did not affect the wave energy attenuation performance significantly.