• Journal of Biosystems Engineering
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• v.6 no.1
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• pp.39-47
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• 1981

For purpose of investigation the proper paddy field condition in performance of rice transplanter according to the various elapsed times (0.5, 1, 1.5, 2 days) after puddling and plowing (12, 15, 18 cm depth), this experiment was carried out on the paddy field located in Chil Am Dong, Jin Ju City, from April to May in 1980. The results are summarized as follows; 1. The practical working power for the elapsed time 0.5 days and plowing depth 18cm was about 0.8 ps, which was the highest among the plots, so the power out-put(2.5~3.5 p.s) of these engines are considered to be enough for the transplanting under these field conditions. 2. The percentage of slip increased proportional1y to the plowing depth and decreased proportionally to the elapsed time after puddling, and the highest and lowest percentages of slip were 42.5% in elapsed time 0.5 days, plowing depth 18 cm, and 26.5% in elapsed time 2 days, plowing depth 12 cm, respectively. 3. In the plot of elapsed time 2 days and plowing depth 12 cm, the planting distance was 13.9 cm, which was closed to the proper planting distance 14 cm. 4. The percentage of missing hill was lowest(1.5%) in the plot of elapsed time 2 days and plowing depth 12 cm. 5. The planted depth in the plot of the elapsed time 2 days and plowing depth 15 cm was 2. 95 cm, which was closed to the proper planting depth 3 cm. 6. The angle of planting postures in the plot of elapsed time 2 days and plowing depth 12 cm was $89^{\circ}$, which was closed to the desirable posture angle $90^{\circ}$. 7. The deviation from the straight transplanting line was lowest in the plot of the elapsed time 2 days and plowing depth 12 cm. 8. From the results above mentioned, it is recommended that the field condition under the elapsed time 2 days and plowing depth 12 cm is the most favorable one for the working performance of rice thansplanter.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.6
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• pp.352-360
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• 2002

This study was carried out to find out the effect of Milk vetch(Astragalus sinicus L.) on growth, and yield of rice, physicochemical properties of soil, reduction rate of nitrogen fertilization, and soil improvement under the different plowing time with Milk vetch cultivated in paddy field, plowing at maximum blooming, last blooming, fruiting stages. The fresh weight of Milk vetch at each plowing time of maximum blooming, last blooming and fruiting stage was 22,500, 20,000, $12,500kg\;ha^{-1}$ respectively. Content of total nitrogen at three plowing times was 2.95, 2.66, and 2.47% and the C/N ratio were 15.7, 18.0, and 19.2, respectively. Physico-chemical properties of soil were improved in cultivated milk vetch, the content of T-N. OM and porosity ratio were increased while the content of $P_2O_5$ and bulk density, solidphase ratio were decreased compared to noncultivated milk vetch. Content of $NH_4-N$ in soil was highest plowing at maximum blooming stage and appeared an increasing tendency according to increased nitrogen level. Amount of nitrogen fertilizer by rice was highest plowing at maximum blooming stage and appeared an increasing tendency according to increased nitrogen level. Nitrogen-use efficiency was high in $33kg\;ha^{-1}$ nitrogen level at three plowing times. The number of spikelets per $m^2$ was high in plowing at maximum blooming stage, last blooming stage and the percentage of ripeness was high in fruiting stage of milk vetch. So the rice yield was increased 9%, 8% in $55kg\;ha^{-1}$ nitrogen level plowing at maximum blooming stage, last blooming stage and 1% in $77kg\;ha^{-1}$ nitrogen level plowing at fruiting stage compared to conventional cultivation.

• Magazine of the Korean Society of Agricultural Engineers
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• v.12 no.3
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• pp.2019-2028
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• 1970

1. Experiments were made for the efficient plowing method by the 4 wheel tractor, the results are as follow; 1) In case of plowing of inner side of the field, the efficient turning method to be the smallest turning time is the $\Omega$-shaped turning method in the turning distance less than 2r (r is the minimum turning radius of the tractor), and also, it is the U-shaped turning method in the turning distance larger than 2r. 2) 2.5r is most efficient in the unit turning section 'w' on plowing of the inner side of the field. 3) In case of plowing of outer side of the field, intermitted plowing method is efficient in case of W>-0.0345 L + 35.84, and also, semi-followed plowing method is efficient in case of W<-0.0345 L + 35.84. 4) The smaller the width of outer side of outer side of the field 'I' is, the higher is the plowing efficiency, and it is estimated that the minimum value 2r is suitable to 'I' in plowing of inner side and outer side of the field. 2. Study on the correlation between the unit field and plowing efficiencies obtained the following results; 1) plowing efficienies increase generally according as length-width ratio L/W and area A increase. 2) Percent of increase of plowing efficiencies decreases generally according as length-width ratio and area enlarge. 3) The limit that change of T is large owing to L/W is 6 for 20 a, 5 for 30 a, 4 for 50 a, 3 for 80 a, less than 2.5 for 100 a, generally, in L/W-T curve. 4) Rate of change of T-A curve is similar to rate of change of $T=A-\frac{2}{3}$ curve in spite of influence of L/W. 5) In case that length-width ratio is more than 3, effects of increase of 10 a area influenced upon plowing efficiencies are as much as effects of about 5 increase of length width ratio without correlation of size of the field. 6) In case that length-width ratio is 2 to 3, effects of increase of 10 a area influenced upon plowing efficiencies are as much as effects of about 4 to 2 increase of length-width ratio without correlation of size of the field, and the effects decrease according as not only length-width ratio decreases but also area increases, generally.

• Magazine of the Korean Society of Agricultural Engineers
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• v.12 no.3
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• pp.2035-2042
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• 1970

Korean Janggi and Western plow to have developed for a long time in the east and west were tested and compared in their draft resistance. The charaderistic of Korean Janggi and plow to be able to make deep plowing, on of the most important factors influeneed the increased yield, were ofserved. The study was undertaken to obtain these basic factors' to device and construct the deep plowing Janggi. The results were as follow; 1. The draft resistance of Korean Janggi far less than that of plow and on the dry field, the influence of soil moisture contant to the draft resistance was larger in the Korean Janggi than in the western plow, but on the rice paddy, there was not differences between them. 2. The plow was more stable than that of Janggi in their operation. 3. The relation ship between the specific draft resistance and plowing depth was shown bygthe carved equation. $$K=Ax+\frac{B}{x}+C$$(K ; specific draft restance, x; plowing depth) A, B, C; Constant controled by soil and instrument factor) 4. Minimam values of the specific draft resistance were as follow; a. On the dry field; Korean Janggi; x = $8{\sim}14cm$ $4K=280{\sim}330gr/cm^2$$ Westean plow; x=$10{\sim}12cm$ $$K=480{\sim}490gr/cm^2$$ 6. On the rice paddy; Korean Janggi; x=$8{\sim}12cm$ $$K=255{\sim}280gr/cm^2$ Western plow; x=$7{\sim}10cm$ $$K=415{\sim}420grc/m^2$$

• Journal of Biosystems Engineering
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• v.25 no.3
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• pp.195-202
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• 2000

This study was conducted to recognize a possibility that cone index can be used as a means of evaluating the tillage workability. Cone indexes were measured every 24 hours after rainfall at the experimental plots, and the rotary and plowing operations were conducted at the same time. The workability was evaluated on a basis of three categories of good, fair and poor depending on the quality of the performed works. Although the workability was affected by many factors such as soil type, moisture content ground slope and weather condition, the duration and amount of rainfall were of most influence. Results of the study showed that a good workability was resulted from the cone indexes greater than an average of 552 kPa for rotary operations and 671 kPa for plowing operations. Fair work was obtained with cone indexes greater than an average of 331 kPa for rotary operations and 459 kPa for plowing operations. The cone indexes less than an average of 171 kPa and 149 kPa resulted in poor workabilities for rotary and plowing operations, respectively. The experimental results may provide a general guideline for evaluating the tillage workability by cone index.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.5
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• pp.489-496
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• 2006

The random-based cleaning algorithm is a simple algorithm widely used in commercial vacuum cleaning robots. This algorithm has two limitations, that is, cleaning takes a long time and there is no guarantee that the cleaning will cover the whole cleaning area. This has lead to customer dissatisfaction. Thus, in recent years, many intelligent cleaning algorithms that takes into consideration information gathered from the cleaning area environment have been proposed. The plowing-based algorithm, which is the most efficient algorithm known to date when there are no obstacles in the cleaning area, has a deficiency that when obstacle prevail, its performance is not guaranteed. In this paper, we propose the Group-k algorithm that is efficient for that situation, that is, when obstacle prevail. The goal is not to complete the cleaning as soon as possible, but to clean the majority of the cleaning area as fast as possible. The motivation behind this is that areas close to obstacles are usually difficult for robots to handle, and hence, many require human assistance anyway In our approach, obstacles are grouped by the complexity of the obstacles, which we refer to as 'complex rank', and then decide the cleaning route based on this complex rank. Results from our simulation-based experiments show that although the cleaning completion time takes longer than the plowing-based algorithm, the Group-k algorithm cleans the majority of the cleaning area faster than the plowing algorithm.

• Journal of Biosystems Engineering
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• v.23 no.6
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• pp.539-548
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• 1998

This study was intended to develop a load spectrum acting on a transmission of agricultural tractors. Transmission loads were measured at the input shaft of the transmission and final drive shaft of the tractors. The measurement were conducted in five field conditions at two speed levels under plowing operations in Korea. Two torque transducers were developed for the respective load measurements and other necessary instrumentations were made to collect the data and store them in a data logger. The time-histories of the torque loads were analyzed and transformed into the load spectra using the rainflow counting and Smith-Watson-Topper methods. Comparisons of the load spectra developed under different conditions were made to investigate their characteristics. The effects on the load levels of soil and plowing speeds were also investigated. Finally, a load spectrum combining the results of the spectrum analysis was developed and proposed as a load source for the reliability test of transmissions.

• Journal of The Korean Society of Grassland and Forage Science
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• v.27 no.3
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• pp.209-218
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• 2007

This experiment was conducted to investigate effect of plowing frequency and sowing dates on the agronomic characteristics, feed value, weed yield and palatability of silage corn. Treatments were a basal treatment(C: May 5 seeding, plowing once, weeding control once), T1(May 12 seeding, plowing twice, weeding control 0 time), T2(May 19 seeding, plowing three times, weeding control 0 time, T3(May 26 seeding, plowing four times, weeding control 0 time) and T4(June 2 seeding, plowing five times, weeding control 0 time). The experiment was performed at the College of Life and Natural Sciences of Sangju University in Sangju in 2006. The plant height and ear height showed highly in order to C > T1 > T2 > T3 > T4 treatment, leaf length was the highest at T2 (96.0cm). Leaf width and number of dead leaf were the highest at C and T3 (11.2cm), C, C and T1 (4.6), respectively. Stem diameter was the highest at T3 as 31mm, while T2 was the lowest as 25mm (p<0.05). Ear circle showed highly in order of C > T1 > T4 > T3 > T4 (p<0.05), and tip filling degree was the highest at C treatment as 8.8, while T4 treatment was the lowest as 6.0 (p<0.05). The stem hardness and grain hardness were C < T1 < T2 < T3 < T4 (p<0.05). Stem saccharinity was T1(6.1%) was the highest, while T2(3.0%) was the lowest(P<0.05). Fresh yield of weed was the lowest at C treatment as 500 kg/ha, but T1 treatment was the highest as 44,100 kg/ha (p<0.05). Weed coverage rate showed highly in order of T1 > T2 > T3 > T4 > C treatment (p<0.05). Fresh yield of corn was the highest at C treatment as T3,550 kg/ha, but T4 treatment was the lowest as 65,500 kg/ha (p<0.05). Dry matter yield of corn showed highly in order of C(26,978 kg/ha) > T1(26,130 kg/ha) > T2(20,255 kg/ha) > T3(20,255 kg/ha) > T4(17,508 kg/ha) treatment (p<0.05). Crude protein content was T1(7.69%) > T4(7.42%) > T2(6.34%) > T3(5.99%) > C(5.91%) treatment (p<0.05), and Crude fat content showed highly in order of C (2.13%) > T1(2.04%) > T2(1.96%) > T3(1.95%) > T4(1.84%) treatment. Relative palatability of Holstein, Korean native goat and spotted deer was the highest at C treatment, but Korean native cattle was the highest at T1 treatment.

• Journal of Biosystems Engineering
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• v.2 no.1
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• pp.49-54
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• 1977

In order to obtain the field efficiency of the power tiller plowing on the various size of and its length-width field tests were performed with 8ps.10ps. power tiller popularly used in the korean rural area, and Satoh 5ps. made in Japan, Land Master 5ps. made in England were tested to compare with the field efficiency of the above power tillers. The results obtained in this tests were as follows ; 1. In considering of the resting time and the refueling time and others, the field efficiency of Satoh was the highest among the power tillers as to be 80%, at the 8ps. power tiller 76.5%, at the 10ps. power tiller 79.3% and the lowest field efficiency was obtained at the Land Master as 75.7%. 2. The field efficiency of the each power tiller increased as the ratio of the length to width of the field was increased. 3. The increasing rate of field efficiency was much bigger in the below the ratio of 5 : 1 but at the upper ratio increased above, the ratio was nearly constant. 4. The field efficiency of the power tiller was higher at the smaller power tiller than the larger, except the Land Master , because of easily operating and turning of the power tiller by virtue of its lighter weight.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.32 no.2
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• pp.137-145
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• 2022

Objectives: This study aimed to identify PM₁₀ mass concentration levels and conduct peak identification during five tasks in agricultural works. Methods: We investigated five agricultural tasks in 12 farms, which were harvesting, plowing, sowing, planting, and decapitation. All samples were measured by using the portable aerosol spectrometer(PAS 1.108) and the aerosol monitor(SidePak AM520). The collected data were compared with the national PM₁₀ concentrations. They were calculated to descriptive statistics, independent t-test, or ANOVA, and the peak identification on time series graph. Results: The ten investigated farms showed no significant difference with the national PM₁₀ concentrations, but the two greenhouses(AM, 143.31, 85.16 ㎍/m³) showed significant difference(p<0.05). As a result of the peak identification, the harvesting tasks showed repeated peak occurrence with the background concentration level of about 50 ㎍/m³. For plowing and sowing tasks, the peak occurred intermittently when the working was conducted near the sampling sites. Among the five tasks, the arithmetic mean of the harvesting task was 138.84±294.71 ㎍/m³, which was significantly higher than the other tasks(p<0.05). In addition, the case of using a tractor was higher than the case of not using the tractor(p<0.05), and the driver's seat showed the highest concentration(AM, 95.81 ㎍/m³). Conclusions: Works in greenhouses might have exposure to PM₁₀, while outdoor works is similar to general atmospheric PM₁₀ concentration levels. However, there is a possibility of intermittent exposure to high concentrations of PM₁₀ depending on the characteristics of agricultural tasks.