• Journal of Biosystems Engineering
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• v.24 no.5
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• pp.383-390
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• 1999

When a tractor travels slope lands, problems of operator safety and the reduction of job efficiency usually occur. Therefore, maintaining the tractor body being horizontal is critical to improve the security of traveling and the job performance. An experiment was made in a soil bin using the experimental model system built and equipped with a leveling control system. Adaptability of the control system was tested and investigated by analyzing system response in time and frequency domains. Control response time of hydraulic cylinder with 10lpm flow rate on a step input of 10$^{\circ}$slope was about 0.42sec. And it showed a linearly increasing trend without any hunching state. A steady state error of 0.6$^{\circ}$occurred but it was negligible. The hydraulic control system showed a little phase differences within the range of 0.4Hz input frequency. The experimental model showed that implementation of the proposed tractor control system to on slope lands tractor was feasible.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.473-478
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• 1998

Dead animals amended with agricultural rersidues are utilized ai a compost to promote soil fertility and reduce environmental pollution by traditional methods of livestock mortalities. The full-scale bin composting swine mortality in roofed system with three amendments was very successful in reaching sufficient temperature above 55$^{\circ}C$ long enough for pathogen kill. The average temperature of tile compost material in dead swine amended with corn stover increased rapidly to 64$^{\circ}C$ on the 2nd day after primary composting and dropped to near ambient temperature on the 140th day of composting. The composting temperature of corn stover and wheat straw is more efficient for swine carcass composting than that of sawdust.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.251-258
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• 2008

The use of reinforced earth walls in permanent structures is getting it's popularity. Despite a number of advantages of reinforced earth walls over conventional concrete retaining walls, there exit concerns over long-term residual deformation when subjected to repeated and/or cyclic loads, during their service period. In this investigation, the effect of preloading in reducing long term residiual deformation of back-to-back reinforced soil wall under sustained and/or repeated loading enviormentment using a series of reduced-scale model tests. It is found that the preloading technique can be an effective means of controlling residual deformations of reinforced soils under varisous loading conditions.

• Agricultural and Biosystems Engineering
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• v.1 no.2
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• pp.67-72
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• 2000

A dynamic draft model is necessary to analyze mechanics of tillage and to design optimal tillage tools. In order to deal with draft dynamics, a neural network paradigm was applied to develop dynamic draft models. For the development of the models, three kinds of tillage tools were used to measure drafts in the soil bin and a time lagged recurrent neural network was developed. The neural network had a structure to predict dynamic draft, having a function of one-step-ahead prediction. A procedure for network prediction model identification was established. The results show promising modeling of the dynamic drafts with developed neural network.

• Journal of Biosystems Engineering
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• v.16 no.1
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• pp.9-17
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• 1991

A dynamometer was designed and constructed to measure three directional forces and moments of pull type implement with eliminating the interference between the forces. The dynamometer consists of a linear motion bearing, self-aligning bearings, universal joints, and cantilevers where strain gages were attached. A data acuquisition system was developed to collect data and to analyze them. The data acuquisition system consists of the dynamometer, a potentiometer to measure the implement depth, strain amplifiers, a A/D converter, and an IBM-AT compatible microcomputer. Program, written in C language, was developed to read data from tranducers with given interval, to calculate forces and moments, to display them on screen, and to store them on disk. The calibration results showed that cantilevers had good linearity and there was no interference among directional forces. When applied loads were reduced with constant rate, hysteresis was appeared on the dynamometer. It might to be reduced by using ball bearings instead of self-aligning bearings.

• Biomolecules & Therapeutics
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• v.29 no.1
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• pp.1-10
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• 2021

COVID-19 has caused extensive human casualties with significant economic impacts around the globe, and has imposed new challenges on health systems worldwide. Over the past decade, SARS, Ebola, and Zika also led to significant concerns among the scientific community. Interestingly, the SARS and Zika epidemics ended before vaccine development; however, the scholarly community and the pharmaceutical companies responded very quickly at that time. Similarly, when the genetic sequence of SARS-CoV-2 was revealed, global vaccine companies and scientists have stepped forward to develop a vaccine, triggering a race toward vaccine development that the whole world is relying on. Similarly, an effective and safe vaccine could play a pivotal role in eradicating COVID-19. However, few important questions regarding SARS-CoV-2 vaccine development are explored in this review.

• Geomechanics and Engineering
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• v.24 no.4
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• pp.337-348
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• 2021

Brillouin Optical Frequency Domain Analysis (BOFDA) is a distributed fiber optic sensing (DFOS) technique that has unique advantages for performance monitoring of piles. However, the complicated production process and harsh operating environment of offshore PHC pipe piles make it difficult to apply this method to pile load testing. In this study, sensing cables were successfully pre-installed into an offshore PHC pipe pile directly for the first time and the BOFDA technique was used for in-situ monitoring of the pile under axial load. High-resolution strain and internal force distributions along the pile were obtained by the BOFDA sensing system. A finite element analysis incorporating the Degradation and Hardening Hyperbolic Model (DHHM) was carried out to evaluate and predict the performance of the pile, which provides an improved insight into the offshore pile-soil interaction mechanism.

• The Korean Journal of Mycology
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• v.51 no.2
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• pp.141-146
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• 2023

Stem rot symptoms were observed in Gondre (Cirsium setidens) plants growing in a vinyl greenhouse in Taebaek, Korea during a disease survey in June 2022. The plants presented with dark brown to black rot on the stems at or above the soil line. Severely diseased plants displayed wilt and blight. Disease incidence among these plants ranged from 1 to 5%. Three isolates of Rhizoctonia sp. were obtained from the stem lesions of diseased plants. All isolates were identified as Rhizoctonia solani AG-2-2(IV) based on the morphological and cultural characteristics, results of the anastomosis test, and phylogenetic analysis. The pathogenicity of the isolates to Gondre plants was confirmed using an artificial inoculation test. The lesions induced by the inoculation test were similar to those observed in the investigated vinyl greenhouse. Here, we report a case of R. solani AG-2-2(IV) causing stem rot in Gondre.

• The Korean Journal of Mycology
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• v.50 no.1
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• pp.61-64
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• 2022

In July and September 2020, a severe outbreak of stem rot was observed on bonnet bellflower (Codonopsis lanceolata) plants in a farm located in Chuncheon, Gangwon Province, Korea. The symptoms initially appeared on the stem at or above the soil line. Later, the infected stem completely rotted and blighted. The incidence of diseased plants in the field was 2-30%. Ten isolates of Rhizoctonia sp. were obtained from the stem lesions of diseased plants. All isolates were identified as Rhizoctonia solani AG-4 based on the morphological characteristics and anastomosis test. Three isolates of R. solani AG-4 were tested for pathogenicity on bonnet bellflower plants through artificial inoculation. All tested isolates induced stem rot symptoms on the inoculated plants. The symptoms were similar to those observed in plants from the farm. This is the first report of R. solani AG-4 causing stem rot in bonnet bellflower.

• The Korean Journal of Mycology
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• v.50 no.2
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• pp.143-147
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• 2022

Sclerotinia rot symptoms were observed in stringy stonecrop (Sedum sarmentosum) plants growing in vinyl greenhouses in Yeoju and Icheon, Gyeonggi Province, Korea, during disease surveys in spring 2019 and 2020. The initial symptoms were soft rot on stems and leaves at or above the soil line. Furthermore, the symptoms progressed upwards, and the infected plant parts exhibited white to grayish-yellow discoloration. The infestation of diseased plants in the vinyl greenhouses was 1-5% at the two locations examined. Eight isolates of Sclerotinia sp. were obtained from lesions of the diseased plants. The isolates were identified as Sclerotinia sclerotiorum based on their morphological and molecular characteristics. In addition, artificial inoculation tested three isolates of S. sclerotiorum for pathogenicity on stringy stonecrop plants. All the tested isolates caused Sclerotinia rot symptoms in the inoculated plants. The symptoms were similar to those observed in plants from the vinyl greenhouses investigated. This study is the first report of S. sclerotiorum causing Sclerotinia rot in stringy stonecrop.