• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.24-24
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• 2003

Since Rice bacterial grain rot (RGBR) was reported at 1986 in Korea, it has been severely occurred in 1994, 1995, 1998, and especially around 16,609 ha in 2000, and became a major disease in rice cultivation field. This study was focused on investigation of ecology of RGBR, weather conditions that affect development of epidemics, and development of an effective RGBR forecast system based on weather conditions during the rice heading period.(중략)

• Journal of Biosystems Engineering
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• v.34 no.5
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• pp.325-330
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• 2009

This study was performed to develop accelerated life test methods for agricultural tractor transmission receiving variable load. To acquire parameters for calculation of accelerated life test, endurance tests were performed under different torque conditions. Test results showed that the shape factor of Weibull distribution was 1.5 and fatigue damage exponent was 5.4. The calculated test time was 5,877 hours under the conditions of average life (MTBF) 3,000 hours and 90% reliability for one test sample. According to the linear cumulative damage rule, test time could be reduced using increased test load. Test time could be reduced by 252 hours when 1.2 times of the rated load compared with 0.67 times of the rated equivalent load calculated by load spectrum of the agricultural tractor. Calculated acceleration coefficient was 23.3.

• The Korean Journal of Applied Statistics
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• v.10 no.1
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• pp.15-27
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• 1997

Randomized block design (RBD) with three replication is very frequently adopted in agricultural experiments of the Rural Development Administration of Korea. Even though it works well in field trials of traditional crops, it may not accomodate trial site conditions and/or experimental environment. In this research report, we deal with two such cases. The first case is for a crop experiment in green houses. In house conditions, RBD may not be appropriate since it cannot reflect two directions of the yield gradient. So, a Latin square design is suggested as an alternative. The second case is for local field experiments of the newly-inbred rice. RBD with three replications is used without doubt for decades, even though the site layout is not appropriately shaped for the design. In this case, we suggest the RBD in two blocks with multiple replicates for control varieties as an alternative. To improve the quality of statistical experimental designs in over one-thousand agricultural trials performed annually in the Rural Development Administration, we need to re-train agricultural researchers on the design and analysis of experiments and call for concerns of Korean statisticians.

• Structural Engineering and Mechanics
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• v.53 no.3
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• pp.411-427
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• 2015

Based on linear elastic theory of quasicrystals, various equations and solutions for quasicrystal beams are deduced systematically and directly from plane problem of two-dimensional quasicrystals. Without employing ad hoc stress or deformation assumptions, the refined theory of beams is explicitly established from the general solution of quasicrystals and the Lur'e symbolic method. In the case of homogeneous boundary conditions, the exact equations and exact solutions for beams are derived, which consist of the fourth-order part and transcendental part. In the case of non-homogeneous boundary conditions, the exact governing differential equations and solutions under normal loadings only and shear loadings only are derived directly from the refined beam theory, respectively. In two illustrative examples of quasicrystal beams, it is shown that the exact or accurate analytical solutions can be obtained in use of the refined theory.

• Journal of Sericultural and Entomological Science
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• v.46 no.2
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• pp.80-88
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• 2004

Insect diapause is a delay in development evolved in response to regulatory recurring periods of adverse environmental condition. Diapause has evolved in most insect species to ensure survival under unfavorable environmental conditions and to syncronize of the growth rate of the population. It is not referable to immediately prevailing adverse environmental condition, and thus differs from a delay produced by currently adverse conditions such as low temperatures. This paper was mainly based on the study of Denlinger.

• Journal of Mushroom
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• v.12 no.2
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• pp.88-95
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• 2014

Auricularia auricula-judae is an edible mushroom, which is known as wood ear, free ear, black ear mushroom, and free jelly fish. This study was carried out to obtain the basic information for mycelial culture conditions of Auricularia auriculajudae. According to colony diameter and mycelial density, the media for suitable mycelial growth were PDA and MCM. The optimum temperature for mycelial growth was $25{\sim}30^{\circ}C$. Carbon and nitrogen sources were mannose and malt extract, respectively. The optimum C/N ratio was in the range of 10 to 1 with 2% glucose. Other minor components for the optimal growth were thiamine-HCl and biotin as vitamins, succinic acid and lactic acid as organic acids, and $MgSO_4{\cdot}7H_2O$ and $KH_2PO_4$ as mineral salts.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.1063-1072
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• 1996

Fruit harvesting robots should have more diversity and flexibility in the working conditions and environments than industrial robots. This paper presents an efficient optimization algorithm for redundant manipulators to avoid obstacles using dynamic performance criteria, while the optimization schemes of the previous studies used the performance criteria using kinematic approach. Feasibility and effectiveness of this algorithm were tested through simulations on a 3-degrees-of-freedom manipulator made for this study. Only the position of the end-effector was controlled , which requires only three degrees of freedom. Remaining joints, except for the wrist roll joint, which does not contribute to the end-effector linear velocity, provide two degrees of redundancy. The algorithm was effective to avoid obstacles in the workspace even through the collision occurred in extended workspace, and it was found be to a useful design tool which gives more flexibility to design conditions nd to find the mechanical constraints for fruit harvesting robots.

• Proceedings of the Korean Society of Community Living Science Conference
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• 2011.10a
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• pp.117-117
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• 2011

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.371-374
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• 1999

Mountain agricultural land should become to the land use considering natural environmental conditions with characteristics of natural suitability . In this study , an evaluation of natural suitability was done for Pyongchang-gun , Kangwon-Do which has a lot of mountain agricultural lands using GIS according to the kind of land use (paddy, field, ordinary upland field, grassland, orchard land, forest).

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2003.10a
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• pp.144-144
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• 2003