• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2000년도 THE THIRD INTERNATIONAL CONFERENCE ON AGRICULTURAL MACHINERY ENGINEERING. V.II
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• pp.438-445
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• 2000

Positioning garlic cloves in upright standing in garlic field has been regarded as a very important job because it affects clove rooting, growing and, eventually, quality and yield in garlic production, Because of the geometrical uniqueness and irregularity of garlic cloves in shape, the planting operation has been conducted by manual work that needs a tremendous human labors and increases garlic production cost. The overall objective of this research was to develop garlic planting machine through investigating physical properties of garlic and designing clove upright positioning device after figuring out the factors affecting metering device and upright clove positioning mechanism. With the outcomes of the metering and posture positioning experiment, a garlic clove planter having twelve planting rows was developed for 37kW type tractor and feasibility test was carried out in the field. And, According to the performance test and cost analysis, the planter could accomplish planting operation of one hectare plot in 6.3 hours giving 48 times better efficiency, 6.3hrs/ha, and 74.2% of production cost reduction effect, 1,092,546won/ha, than the manual works of 299hrs/ha and 282,258won/ha. And, break-even point ofthe planter was calculated as of 2.71 hectares.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1996년도 International Conference on Agricultural Machinery Engineering Proceedings
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• pp.1031-1040
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• 1996

Spawn bottle cutting and spawn cake shredding machine has been developed to save the farm labor and operating cost for mushroom growing farmers. The prototype can cut the bottom and side of the bottle while shredding the spawn cake by one farmer. The cutting plastic shell is done by two couples of high speed disc saws that can cut cross section and lengthwise two side of the bottle, while spawn cake shredding is done by spike teethed rotating drum and wiremesh concave. The optimum speed of cutting disc saw was observed 1.700rpm both the cross cutting saw and lengthwise cutting saw in consideration of the cutting accuracy. And the location for the instalation of cross cutting disc saw was considered as around 4 mm above the table bottom , while the optimum clearance between two edges of lengthwise cutting disc saw was showed 86mm. For the sawdust spawn cake shredder , proper size of spawn sawdust granule was observed in the 15 x 15mm size withmesh concave with the shredding rum speed of 500rpm. The prototype can be reduce 73 per cent of working hours with the working cost reduction of 49 per cent compare with those of conventional operation.

• Journal of Biosystems Engineering
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• 제27권6호
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• pp.547-556
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• 2002

Upright positioning of garlic cloves in mechanical planting has been considered as an essential process because pose of garlic affects not only initial budding and rooting of garlics but quality and yield. Due to the geometrical uniqueness and irregularity of garlic cloves in shape, manual planting operation has been conducted. The overall objective of this research was to determine design factors for designing a garlic clove planter The results are summarized as follows : 1. A vibrating-type clove-metering device was designed and tested. Effects of tilted angle of metering plate and magnitude of vibration on metering performance were investigated. The successful planting rates of the metering device were 96.7% for Hanji varieties. 2. Clove upright-positioning device, posture inducer was designed and tested. When the clearance between the hoppers was set at 4mm, the rates of upright positioning of the device were 92.2% for with Hanji varieties. 3. Optimum metering performance was observed at the plate tilted angle of 80。 with the posture type positioning device.

• Journal of Positioning, Navigation, and Timing
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• 제7권2호
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• pp.91-103
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• 2018

Conventional inertial measurement units cannot be used in the spinning vehicle with high rotation rate due to gyro's narrow operation range. By the way, angular acceleration can be measured using the accelerometer array distributed in the vehicle. This paper derives a mechanization for the gyro-free INS in the navigation frame, and proposes a gyro-free INS algorithm based on the derived mechanization. In addition, the proposed algorithm is used to estimate angular velocity, attitude, velocity, and position of a spinning vehicle with high rotation rate. A MATLAB-based software platform is configured in order to show validation of the proposed algorithm. The reference trajectory of a spinning vehicle at 3 round per second, 30 round per second are set up, and the outputs of accelerometer are generated when triads of accelerometer are located at the origin and all the axes. Navigation results of the proposed algorithm for the generated output are presented. The results show that the proposed navigation algorithm can be applied to the spinning vehicle with high rotation rate.

• 항공우주기술
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• 제1권1호
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• pp.28-41
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• 2002

본 논문의 목적은 실제 관성항법센서를 사용하여 개발된 스트랩다운형 관성항법시스템 및 이용 알고리즘에 대한 성능 및 오차를 평가하는 것이다. 시험은 관성항법센서의 조합을 두가지로 나누어 수행하였는데, 서로 다른 바이어스를 갖는 중급의 가속도계와 저급의 가 속도계가 사용되었으며, 자이로의 경우는 FOG(Fiber Optic Gyro)를 사용하였다(SDINS-1, SDINS-2). 관성항법시스템의 성능을 평가하기 위해서 두가지의 시험이 수행되었으며, 3축 운동 시험대를 이용한 지상정지시험과 차량을 이용한 단거리 주행시험을 수행하였다. 단거 리 주행시험의 결과는 정확도 20 mm를 갖는 DGPS(Differential GPS)의 시험결과와 비교 하였으며, 결과 및 오차를 나타내었다.

• 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.

• 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.

• 한국터널지하공간학회 논문집
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• 제11권2호
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• pp.107-115
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• 2009

최근, 도로의 고속화와 직선화로 인해 대단면 장대터널이 증가하고 있다. 그 때문에 터널굴착시 효율성이 극대화된 방법이 요구되고 있는데, 그 중 카트리지형의 기존 화약류 대신 기계화 장전 시스템을 활용한 벌크에멀젼시스템의 도입이 적극적으로 검토되고 있다. 이 연구는 대단면 장대터널에서의 다양한 효율과 터널발파에서의 새로운 공법인 벌크에멀젼시스템을 소개하고자 한다. 그리고 현장 실험을 통해 커트리지 시스템과 벌크에멀젼 시스템의 효율을 비교해보고자 한다.

• Journal of Forest and Environmental Science
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• 제23권2호
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• pp.109-118
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• 2007

본 연구는 임업노동력 현황과 양성방안을 분석하여 향후 임업노동력의 확보 및 임업기계화의 활성화 등을 위한 정책방안의 기초자료를 제공할 목적으로 수행하였다. 산림작업 종별 총 고용인원과 인건비는 매년 조금씩 증가하고 있는 추세이나 벌채 총 고용인력은 오히려 감소하고 있으며, 전문 기계화작업단 구성과 오퍼레이터의 양성이 필요하겠다. 현재 임업현장의 중심적인 활동을 펴고 있는 영림단의 수와 단원수가 해매다 늘어나고 있고 연간 작업일수와 소득도 늘어나고 있는 실정이다. 그러나 기능인영림단의 월평균 작업일수가 15일로 연간 작업일수가 180일에 불과하였다. 우리나라의 연간 총 숲가꾸기 사업량을 중심으로 기능인영림단 및 단원수를 산출한 결과, 약 349개의 기능인영림단이 필요하고 이에 따른 기능인영림단 1개당 단원수를 12명으로 적용했을 경우, 전체 기능인영림단의 단원수는 약 4,185명이 필요하다는 것을 알 수 있었다. 또한 우리나라의 연간 목재 생산량을 중심으로 타워야더형 임목수확작업시스템을 적용하여 적정 기계화영림단 및 단원수를 산출한 결과, 250개의 기계화영림단이 필요하고 기계화영림단당 단원수를 5명으로 적용했을 경우, 전체 기계화영림단의 단원수는 1,250명이 필요하다는 것을 알 수 있었다.

• 한국식품저장유통학회지
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• 제10권3호
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• pp.297-301
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• 2003

농산물의 저온저장 및 고습조건에서 안전하게 유통할 수 있는 골판지 포장상자를 개발하기 위하여 원지의 구성, 라이너의 발수도, 골형태의 차이에 따라 수분흡습 특성과 압축강도와의 관계를 구명하기 위해 각각 원지특성을 달리하여 이중 양면 골판지를 재료로 사용하여 시험하였다. 온도변화에 따른 골판지 함수율 변화는 골판지 원지 종류, 발수도 차이등에 관계없이 거의 일정한 값을 나타냈다. 상대습도 변화에 따른 골판지의 함수율 변화는 상대습도에 크게 영향을 받는 것으로 나타났으며 골판지의 수분흡습은 발수도 보다는 원지에 구성에 따라 영향을 많이 받는 것으로 나타났다. 또한 수직압축강도는 상대습도가 증가함에 따라 크게 감소하여 상대습도가 수직압축강도에 미치는 영향이 매우 크며 상대습도가 증가함에 따른 수직압축강도의 저하비율은 골판지의 종류에 관계없이 거의 같은 것으로 나타났다. 따라서 저온고습 조건에서 안전하게 내용물을 보호할 수 있는 저온유통용 농산물 골판지 상자의 개선을 위해서는 고품질 원지의 생산기술 개발 및 골판지 상자의 구조개선 연구가 우선되어야 할 것으로 판단된다.