• Journal of Animal Science and Technology
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• v.47 no.1
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• pp.107-114
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• 2005

Experiments were carried out to evaluate the air speed distribution of an enclosed nursery pig bay in summer and winter. The data taken by experiments were compared to validate with the calculated air speeds by a commercial CFD code, FLUENT. Air basically enters into the bay through perforated circular ducts overhanged on the ceiling, leaves through a exhaust fan attached on the end-wall of the bay. Air speeds were measured as 2 ${\sim}$ 2.5 mls at the perforated holes in the duct in winter and 7 mls in summer. The validation showed that a CFD simulaton is one of feasible methods to predict airspeed distribution in the nursery pig bay.

• Journal of Drive and Control
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• v.20 no.1
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• pp.16-26
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• 2023

Although the upland field area of Korea is high as 44.8%, the platform optimized for the upland field is insufficient. It is necessary to develop an optimized platform for the upland field because the upland field environment is an irregular environment with many slopes. In addition, due to the characteristic of agricultural operations, the traction power and torque of the platform have to be sufficient. Therefore, in this study, a simulation model that can predict the traction power and driving torque of a crawler-type platform for the upland field was developed and validated using the specifications of the crawler platform. The simulation model was developed using Amesim (19.1, Siemens, Germany). The development of the model was conducted using the specifications of the platform. A measurement system was developed to validate the simulation model. The traction power data of the simulation model was validated with the traction force and vehicle speed. The driving torque data of the simulation model was validated with the torque of the sprocket on the crawler system. As a result of the analysis, the error between measurement and simulation results occurred within 10%, and it was determined that the traction power and driving torque prediction of the crawler platform using this model was possible.

• 한국약용작물학회:학술대회논문집
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• 2008.05a
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• pp.190-191
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• 2008

• Weed & Turfgrass Science
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• v.1 no.4
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• pp.38-43
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• 2012

This study was conducted to predict the yield response of red pepper and to determine the economic weed threshold levels for red pepper cultivation field from competition with the most serious weeds, Amaranthus patulus and Digitaria ciliaris in Youngyang of Korea. Crop yield as a function of weed density was predicted by using a rectangular hyperbola, and their economic threshold levels were determined by using the equation developed by Cousens (1987). The red pepper yield loss models of weeds were predicted as y=304.7/(1+0.063x), $R^2$=0.967 in D. ciliaris and y=281.3/(1+0.1723x), $R^2$=0.952 in A. patulus. Economic thresholds calculated using Cousens' equation were negatively related with the competitiveness of weed. Economic thresholds of each weed were calculated as 18.2 plant $100m^{-2}$ in D ciliaris, and 7.2 plant $100m^{-2}$ in A. patulus.

• Journal of Drive and Control
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• v.21 no.3
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• pp.72-76
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• 2024

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11c
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• pp.698-706
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• 2000

It is very difficult to mechanize tomato harvesting because identifying a tomato partly covered with leaves and stalks is not easy. This research was conducted to develop tomato harvesting robot which can identify a target tomato, determine its three dimensional position, and harvest it in a limited time. Followings were major findings in this study. The first visual system of the harvesting robot was composed of two CCD cameras, however, this could not detect tomatoes which are not seen on the view finder of the camera especially those partly covered by leaves or stalks. The second visual device, combined with two CCD cameras and pan/tilt procedures was designed to minimize the positioning errors within ${\pm}10mm$, but this is still not enough to detect tomatoes partly covered with leaves etc. Finally, laser distance detector was added to the visual system that could reduce the position detecting errors within 10mm in X-Y direction and 5mm in Z direction for the partly covered tomatoes.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.6
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• pp.872-876
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• 2006

The objective of this study was to evaluate Biocom (a protein source containing a high level of glutamine and alanyl-glutamine) as a replacement for glutamine (Gln) in nursery pig diets. Forty-two pigs (fourteen pigs per treatment) weaned at 28 d of age were used in a 28-d performance trial using three dietary treatments: control (no Gln), control supplemented with Gln or Biocom. The control diet was composed of corn, soybean meal, whey and fish meal. Individual body weight, pen feed disappearance and diarrhea were monitored. On d 0, 2, 7 and 14 postweaning, respectively, five pigs per treatment were selected and bled from the anterior vena cava to obtain five replicate samples of blood on each dietary treatment for determination of blood biochemical index. Dietary supplementation of Gln and Biocom did not influence performance, plasma Gln and total serum protein concentration (p>0.05). However, the addition of Gln and Biocom could prevent serum urea nitrogen and serum cortisol from increasing on d 2 postweaning (p<0.05). There were no significant differences (p>0.05) in any of the examined parameters between Gln- and Biocom-supplemented diets. In conclusion, dietary Gln did not influence the performance of early-weaned piglets owing to the complex diet containing whey, but could prevent the increase of serum urea and cortisol. Biocom could be used as a replacement for free pure Gln without any negative effect on early-weaned piglets.

• BMB Reports
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• v.40 no.3
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• pp.419-425
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• 2007

In vitro directed evolution through DNA shuffling is a powerful molecular tool for creation of new biological phenotypes. E. coli $\beta$-galactosidase and $\beta$-glucuronidase are widely used, and their biological function, catalytic mechanism, and molecular structures are well characterized. We applied an in vitro directed evolution strategy through DNA shuffling and obtained five mutants named YG6764, YG6768, YG6769, YG6770 and YG6771 after two rounds of DNA shuffling and screening, which exhibited more $\beta$-glucuronidase activity than wild-type $\beta$-galactosidase. These variants had mutations at fourteen nucleic acid sites, resulting in changes in ten amino acids: S193N, T266A, Q267R, V411A, D448G, G466A, L527I, M543I, Q626R and Q951R. We expressed and purified those mutant proteins. Compared to the wild-type protein, five mutant proteins exhibited high $\beta$-glucuronidase activity. The comparison of molecular models of the mutated and wildtype enzymes revealed the relationship between protein function and structural modification.

• Journal of Forest and Environmental Science
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• v.25 no.3
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• pp.147-155
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• 2009

Higher plants provide valuable genetic assay systems for screening and monitoring environmental pollutants. They are now recognized as excellent indicators of mutagenic effects of environmental chemicals and are applicable for the detection of environmental mutagens both indoor and outdoor. 2,4-dichlorophenoxyacetic acid (2,4-D) is a herbicide commonly used in agriculture. The residues of 2,4-D are present in air, water, soil and edible plants. It constitutes a real hazard to the public health because it's wide spread use in agriculture. Genotoxic effects of 2,4-D on plant cells and potential of higher plants as a biomonitoring system for detecting chemical mutagens are evaluated. It is recommended that higher plant systems have been accepted by regulatory authorities as an alternative biomonitoring system for the detection of possible genetic damage resulting from pollution and the use of environmental chemicals.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.8
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• pp.1076-1079
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• 2002

The DNA fingerprint polymorphism and the genetic relationship were studied by RAPD technology on Chaidamu goat (CG), Chaidamu Cashmere goat (CCG) and Liaoning Cashmere goat (LCG) from Chaidamu Basin of Qinghai province, China. The results showed that: The amplified bands were all 94 in 3 goat populations by using 8 random primers, and the DNA polymorphism frequencies of CG, CCG and LCG were 0.8404, 0.8617 and 0.8511, respectively, and the length of these DNA fragments were 176-2937 bp. The mean heterozygosities of the 3 goat populations were 0.5148, 0.5142 and 0.5075, respectively. The genetic relationship between CCG and CG or LCG were similar (Gst=4.37% and 3.79%; $D_{ij}=0.0109$ and 0.0106), and that between CG and LCG was further (Gst=13.14%; $D_{ij}=0.0230$). These results also showed that the genetic relationship between CCG and LCG was the closest, then CG and LCG, and CG and CCG was distant.