• Journal of Biosystems Engineering
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• v.40 no.4
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• pp.314-319
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• 2015

Purpose: The ratio of straw to grain mass as a function of cutting height affects combine efficiency and power consumption and is an important input parameter to combine simulation models. An equation was developed to predict straw to grain ratios for wheat as a function of cutting height. Methods: Two mass functions, one for straw and one for grain, were developed using regression techniques and measured data collected in west Texas during the summer, and used to predict the straw to grain ratio. Results: Three equations were developed to facilitate the simulation of a combine during wheat harvest. Two mass functions, one for straw and one for grain, were also developed; a quadratic equation describes the straw mass with an $R^2$ of 0.992. An S-shaped curve describes the mass function for grain with an $R^2$ of 0.957. An equation for straw to grain ratio of wheat was developed as a function of cutting height. The straw to grain ratio has an $R^2$ value of 0.947. Conclusions: In all cases, the equations had $R^2$ values above 0.94 and were significant at the 99.9 percent probability level (alpha = 0.001). Although all three equations are useful, the grain mass and straw to grain ratio equations will have direct application in combine simulation models.

• Journal of Biosystems Engineering
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• v.32 no.3
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• pp.190-196
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• 2007

The purpose of this study is to develop a measurement system of cutter conditions for combine header diagnosis during rice harvesting. A load cell was installed at the locker-arm to measure load fluctuation and an acceleration senor was used to monitor vibration signal of cutter bar. The data were collected from a paddy field during harvesting. The tests were conducted with a normal cutter, a loosened cutter, a broken cutter, and a worn-out connecter pin at the field. The vibration signals converted by FFT (Fast Fourier Transformation), filtered, and normalized. The load data and peak values of vibration signals in four different frequency ranges were used to determine the cutting operation and the cutter conditions of combine. The multiple comparison tests showed that the load data and peak values of vibration signals were important to monitor the cutting operation and cutter conditions of combine header.

• Journal of Biosystems Engineering
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• v.11 no.1
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• pp.76-85
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• 1986

This study was intended to examine the failure characteristics and breakdowns of the head-fed type combines generally used on farms. The failure distribution was assumed to follow Weibull distribution function and the Weibull parameters of the major parts, units and combine as whole were estimated by using the data collected in a survey. A computer program for the estimation of the Weibull parameter was developed. Monte Carlo method was used in predicting the time between failures. The results of study may be summarized as follows: 1. The number of failures per combine was 4.83 times per year and 0.3 times per hectare of combines of different ages. 2. According to the Kolmogorov-Smirnov test method, it was proved that the Weibull distribution function is well fitted to the characteristics of the failure and breakdowns of combines. 3. Weibull parameters of failure distribution of the combine as a whole were estimated to give the shape parameter ${\beta}$=1.3089 and the scale parameter ${\alpha}$=105.2409. The combining area with 80% reliability was 1.1 ha, and the probability of operating the combine without any failure for a year, was $2.76{\times}10^{-4}$. 4. The mean time between failures (MTBF) of the combines was predicted to be 3.2 ha of operation, which corresponds to 32 hours of operation.

• Journal of Biosystems Engineering
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• v.32 no.5
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• pp.332-338
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• 2007

Yield mapping is necessary for precision farming. An on-site rice weighing system for a head-feed combine was developed to measure the total weight of rice grain harvested while the combine was operated. A load cell system was used to monitor rice weights accumulated into the combine grain tank using a load cell. This method gave cumulative grain weight readings as a function of time. The system consisted of a load cell, two supporting brackets, and a computer-based data acquisition system. The weights measured with the system from two fields were compared with those obtained with a commercially available electronic balance. The response of the load cell to varying grain weights was linearly modeled, showing a coefficient of determination of 0.998 and a standard error of ${\pm}4.09kg$.

• Journal of Biosystems Engineering
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• v.6 no.1
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• pp.48-59
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• 1981

The major limiting factor on the determination of combine capacity is the frequent occurence of clogging over the some parts of machine when the crop is wet in the case of Japanese self-feeding type combine. And in the case of American conventional combine having big separating parts, the great grain loss and damage occur when the machine is used for rice harvesting. This experiment was carried out to develop the new type threshing and separating equipment. Proto-type thresher which consist of a conical threshing drum and a conical separating sieve rotating around the threshing cone was constructed and tested. In the case of 800 rpm of threshing cone speed, average threshing loss was below 1 percent, separating loss was about 1 percent, grain damage was about 0.4 percent, and average total power required was about 2.6 PS. This design has some problems such as higher power required or wrapping problems under the conditions of feeding long damp straw. But, compared with the conventional combine or thresher, this machine certainly has some potentials for this approach to combine development. The crop feed rate must be increased through improvement of the feeding portion of the threshing cone. And it is required to investigate further about some parameters causing wrapping phenomena.

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.263-271
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• 2003

In this paper, we presents the results of the leading 2 European projects in the real-time train conflict dection and resolution field. One is MARCO(Multi-level Advanced Railways Conflicts Resolution and Operation Control) and the other is COMBINE(enhanced COntrol center for a Moving Block sigNaling systeEm) project. From the results of the survey, we derive the basic principles in order to use in the similar project of Korea Nation Railway.

• Journal of Biosystems Engineering
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• v.20 no.1
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• pp.36-46
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• 1995

The number of possible working days is one of the major factors for estimating the coverage area of a combine harvester. The percentages of possible working days at 24 locations were presented by analyzing the amount of rainfall during the working periods of rice harvesting from the end of September to the end of October for past 20 years. The percentages of possible working days ranged from 75% to 85% in most cases.

• Journal of Korean Society for Quality Management
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• v.22 no.1
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• pp.54-65
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• 1994

Multivariate exponentially weighted moving average (EWMA) control charts for monitoring the variance-covariance matrix are investigated. Two basic approaches, "combine-accumulate" approach and "accumulate-combine" approach, for using past sample information in the developement of multivariate EWMA control charts are considered. Multivariate EWMA control charts for monitoring the variance-covariance matrix are compared on the basis of their average run length (ARL) performances. The numerical results show that multivariate EWMA control charts based on the accumulate-combine approach are more efficient than corresponding multivariate EWMA control charts based on the combine-accumulate approach.

• Journal of Biosystems Engineering
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• v.14 no.2
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• pp.85-93
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• 1989

This study was intended to develop the system which controls header height of combine automatically by means of sensing the difference between the header and the ground surface. A micro-computer was used for the controller. The sensing unit designed for the study was composed of potentiometer, oscillating link, and gage wheel. An electric-hydraulic circuit was driven by microcomputer to control header height of combine. Performance of the control system was tested by computer simulation, stationary operation of header, and traveling on the simulated ground.

• Journal of Biosystems Engineering
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• v.14 no.2
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• pp.94-103
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• 1989

This study was intended to develop the automatic feeding depth control system of the head-feed combine which could feed the rice head into threshing unit at the optimal depth regardless of plant height and uneven ground surface. In the control system, one-board microcomputer was used for the controller instead of conventional electric circuits. Field test of the combine equipped with the control system was conducted to evaluate its overall performance. It was also investigated how the location and time delay of rice head sensor affect the system performance.