• Journal of Biosystems Engineering
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• 제26권6호
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• pp.517-524
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• 2001

Steep and narrow ramp installed in the paddy field makes it difficult and sometimes dangerous to drive agricultural machines on it. Because agricultural machinery become larger and heavier, it is necessary to revise design standard for ramp to provide safe travel. This study was conducted to revise the design standard fur paddy field ramp, especially for its width and slope. A mathematical model predicting travelling path of a tractor on paddy field ramp and farm road was developed and simulated. To verify this model, field tests were carried out. The model could predict trvelling path with RMS Error of 12.5cm and 8.2cm, which were judged to be adoptable fur determining the width of paddy field ramp. By applying this model to 110ps tractor, which was assumed to be the largest tractor in Korea, width of paddy field ramp was determined as over 3.6m. The slope of paddy field ramp, which provided tractor with 10% of the total weight of the tractor and the mounted implement as reaction force at front wheel against ground was analyzed by considering weight transfer effect on a ramp. The result showed that adequate slope of paddy field ramp was 14°.

• Journal of Information Processing Systems
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• 제17권6호
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• pp.1127-1137
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• 2021

Given the different effects of agricultural mechanization on various stages of wheat planting in Henan, this article selects 78 observation samples from Henan, a major wheat-growing province. It uses different research methods (multiple linear regression, social network analysis model, multi-layer sensory nerves network) to conduct a comparative study, and the calculation results of the model show that the experimental results have a strong convergence and consistency. Agricultural mechanization services have significant effects on the three stages of wheat planting: harvesting, plowing and sowing. A higher degree of mechanized service in several stages can reduce the cost of growing wheat on family farms.

• 한국산림과학회지
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• 제97권6호
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• pp.661-668
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• 2008

본 연구는 임업기계화 사업을 추진함에 있어서 임업기계화 사업에 미치는 영향요인을 분석하고, 이들 요인이 사업의 결과 및 효과에 어느 정도 영향을 미치는지 그 관계를 분석하여 향후 임업기계화 사업의 성공적인 집행을 위한 유용한 정책 자료를 제공하고자 수행되었다. 연구방법은 이들 요인들 상호간의 구조관계를 공변량구조모형인 LISREL을 활용하여 분석하였으며, 자료 수집은 임업기계화 사업을 추진 운영하고 있는 사업담당자를 대상으로 설문조사를 실시하였다. 임업기계화 사업성과와 정책만족도, 교육훈련에 관한 응답결과는 보통으로 나타났으며, 정책의 일관성과 법률 및 제도 정비와 임업기계의 보급은 보통보다 낮은 것으로 나타났다. 향후 임업기계화 정책 추진에서 법률 및 제도 정비를 통한 일관성 있는 정책과 임업기계의 보급률을 높이는 정책을 추진할 필요가 있는 것으로 나타났다. 또한 임업기계화 사업에서 정책기반, 임업기계보급과 교육훈련 모두 정책성과에 정(+)의 영향을 미치는 것으로 나타났으며, 정책성과는 정책만족도에 정(+)의 영향을 미치는 것으로 나타났다. 따라서 향후 임업기계화 정책사업을 성공적으로 추진하고 정착시키기 위해서는 임업기계화 정책기반 조성도 중요하지만 더욱 많은 임업기계의 보급 및 오퍼레이터의 교육 훈련이 필요하다는 것을 알 수 있었다.

• Journal of Biosystems Engineering
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• 제43권4호
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• pp.369-378
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• 2018

Purpose: The aim of this study was to construct a saponin content-predicting model using shortwave infrared imaging spectroscopy. Methods: The experiment used a shortwave imaging spectrometer and ENVI spectral acquisition software sampling a spectrum of 910 nm-2500 nm. The corresponding preprocessing and mathematical modeling analysis was performed by Unscrambler 9.7 software to establish a ginsenoside nondestructive spectral testing prediction model. Results: The optimal preprocessing method was determined to be a standard normal variable transformation combined with the second-order differential method. The coefficient of determination, $R^2$, of the mathematical model established by the partial least squares method was found to be 0.9999, while the root mean squared error of prediction, RMSEP, was found to be 0.0043, and root mean squared error of calibration, RMSEC, was 0.0041. The residuals of the majority of the samples used for the prediction were between ${\pm}1$. Conclusion: The experiment showed that the predicted model featured a high correlation with real values and a good prediction result, such that this technique can be appropriately applied for the nondestructive testing of ginseng quality.

• Agricultural and Biosystems Engineering
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• 제2권1호
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• pp.31-36
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• 2001

Based on the viscous flow characteristics of gas through capillary tube, a simple and cheap gas mixing system was developed for controlling gas compositions in CA chambers. The gas flow rate through capillary tube had a linear relationship with pressure, (length)$^{-1}$ and (radius)$^4$ of capillary tube, which agreed well with Hagen-Poiseuille’s law. The relationship between flow rate and combined parameters was described as Q=0.000209724($\pi$ r$^4$P/$\mu$L) and the coefficient of determination was 0.9984. The developed system could control gas concentrations in CA chambers within $\pm$0.3% deviation compared to the preset concentrations. It was possible to predict the required time and required gas flow rate for exchanging the gs in CA chamber to a certain concentration of gas by using the mathematical model developed in this study.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2000년도 THE THIRD INTERNATIONAL CONFERENCE ON AGRICULTURAL MACHINERY ENGINEERING. V.III
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• pp.513-520
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• 2000

An integrated grader which measures soluble solid content, color and weight of fresh apples was developed by NAMRI. The prototype grader consists of the near infrared spectroscopy and machine vision system. Image processing system and an algorithm to evaluate color were developed to speed up the color evaluation of apples. To avoid the light glare and specular reflection, an half-spherical illumination chamber was designed and fabricated to detect the color images of spherical-shaped apples more precisely. A color revision model based on neural network was developed. Near-infrared(NIR) spectroscopy system using NIR reflectance method developed by Lee et al(1998) of NAMRI was used to evaluate soluble solid content. In order to observe the performance of the grader, tests were conducted on conditions that there are 3 classes in weight sorting, 4 classes in combination of color and soluble solid content, and thus 12 classes in combined sorting. The average accuracy in weight, color and soluble solid content is more than about 90 % with the capacity of 3 fruits per second.

• Journal of Biosystems Engineering
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• 제41권3호
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• pp.184-192
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• 2016

Purpose: To solve the decay phenomenon of Hanfu apples that occurs during storage and obtain the best environmental parameters for preserving Hanfu apples using Fluent. Methods: Preservation storage was designed by analyzing the characteristics of Hanfu-apple storage and the natural environment in northeast China. The boundary conditions and simulation of a preservation model were established. Results: Compared with the initial values, the hardness decreased by $1.95kg/cm^2$, the sugar-acid ratio decreased by 20.43, and weight-loss rate was 3.98%. Conclusion: The results for the temperature field and velocity field of the empty storage were analyzed using Fluent. Hanfu apples can maintain good quality during the period of storage, according to our analysis of the Hanfu-apple hardness, weight loss, and change in the sugar-acid ratio during the 90-day preservation period.

• Advances in aircraft and spacecraft science
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• 제7권3호
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• pp.215-228
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• 2020

As is shown in the paper, the Koltunov-Rzhanitsyn singular kernel of heredity (when constructing mathematical models of the dynamics problem of the hereditary theory of viscoelasticity) adequately describes real mechanical processes, best approximates experimental data for a long period of time. A mathematical model of the problem of the flutter of viscoelastic plates moving in a gas with a high supersonic velocity is given. Using the Bubnov-Galerkin method, discrete models of the problem of the flatter of viscoelastic plates flowed over by supersonic gas flow are obtained. A numerical method is developed to solve nonlinear integro-differential equations (IDE) for the problem of the hereditary theory of viscoelasticity with weakly singular kernels. A general computational algorithm and a system of application programs have been developed, which allow one to investigate the nonlinear dynamic problems of the hereditary theory of viscoelasticity with weakly singular kernels. On the basis of the proposed numerical method and algorithm, nonlinear problems of the flutter of viscoelastic plates flowed over in a gas flow at an arbitrary angle are investigated. In a wide range of changes in various parameters of the plate, the critical velocity of the flutter is determined. It is shown that the singularity parameter α affects not only the oscillations of viscoelastic systems, but the critical velocity of the flutter as well.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1999년도 동계 학술대회 논문집
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• pp.130-138
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• 1999

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1998년도 하계 학술대회 논문집
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• pp.72-82
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• 1998