• Journal of Biosystems Engineering
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• 제23권6호
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• pp.629-634
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• 1998

Factory-style plant production system aims to produce the standardized horticultural products with high quality and cleanness. In Korea, researches for year-round leaf vegetables production system are in progress and the most of them are focused on environment control. Automating technologies for harvesting, transporting and grading need to be developed. A lettuce harvesting system applicable to the plant factory was studied. It was composed of an articulated robot with a cutter and a gripper, lettuce feeding conveyor and air blower. Success rate of the developed system was 94.7 %. The system carried out harvesting a lettuce smoothly and the harvesting time was about 6 seconds per lettuce. The results showed a feasibility of robotic lettuce harvesting.

• 한국작물학회지
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• 제29권3호
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• pp.261-266
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• 1984

보리 수확의 기계화를 위한 작업기술체계를 확립하고자 대맥 강보리를 공시품종으로 1982∼'83 2개년에 걸쳐 기종 및 수확시기에 따른 작업능률, 종실손실정도 및 곡물품위 등을 대상으로 일련의 시험을 수행한 바 그 결과를 요약하면 다음과 같다. 1. 출수 30일후 종실의 수분함량은 54.3％ 줄기는 59.5％로 이들은 일수가 경과함에 따라 직선적인 감소를 보였는데 특히 출수후 35∼40일 사이에서 일당 감소율이 각각 3.1％, 3.9％로 가장 컸다. 2. 관행(인력)에 비해 수확 및 탈곡작업시간은 평균 콤바인 93％, 바인다 81％, 초예기 44％를 절감시킬 수 있었고, 소요경비도 콤바인 44.5％, 바인다 36.5％, 초예기 20.0％를 각각 절약할 수 있었다. 3. 수량에 대한 10a당 평균 손실률은 인력이 5.8％로 가장 적었고 다음이 바인다로 7.0％, 콤바인 9.1％, 초예기가 13.8％로 가장 많았으며 수확시기별로는 출수후 일수가 더함에 따라 다소 증가하는 경향이었다. 4. 수확시기에 있어서 출수후 30일을 제외하고는 종실이 지녀야 할 일반적인 품위에 대한 차이가 미미한 점으로 볼 때 기계를 이용한 수확작업은 출수후 35일이 경과한 시기로서 작업능률 즉 소요시간, 경비 및 손실량 등의 관련요인들을 가장 유리하게 발현시킬 수 있었다.

• Journal of Biosystems Engineering
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• 제35권6호
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• pp.367-372
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• 2010

Consumption of pepper, a major spice vegetable used for seasoning Kimchi, continues to increase, but cultivation is in decline due to shortage of rural labor in Korea. The 39.2% of total labor requirement for conventional pepper cultivation was available for harvesting work. Therefore conventional manual harvesting should be turned to mechanical harvesting for labor-saving, cost-reducing and easy work. Surveys on conventional pepper cultivation patterns, labor requirements for various pepper cultivation works, and farmers' opinions on the mechanization of pepper harvesting were conducted to obtain basic informations. The labor requirement for pepper harvesting was 954 h/ha out of a total labor requirement of 2,436 h/ha for pepper cultivation. Harvesting was the hardest work, and hiring workmen for harvesting was also difficult. Farmers preferred to develop a small-scale pepper harvester using agricultural tractor or cultivar. Most farmer agreed to change cultivation pattern for mechanization of pepper harvesting, but hesitated to adopt new one-time-harvesting pepper varieties.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2000년도 THE THIRD INTERNATIONAL CONFERENCE ON AGRICULTURAL MACHINERY ENGINEERING. V.II
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• pp.354-362
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• 2000

In Korea, researches on year-round leaf vegetables production system are in progress, most of them focused on environmental control. Therefore, automation technologies for harvesting, transporting, and grading are in great demand. A robot system for harvesting lettuces, composed of a 3-DOF (degree of freedom) manipulator, an end-effector, a lettuce feeding conveyor, an air blower, a machine vision system, six photoelectric sensors, and a fuzzy logic controller, was developed. A fuzzy logic control was applied to determine appropriate grip force on lettuce. Leaf area index and height were used as input variables and voltage as an output variable for the fuzzy logic controller. Success rate of the lettuce harvesting was 94.12%, and average harvesting time was approximately 5 seconds per lettuce.

• Journal of Biosystems Engineering
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• 제25권1호
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• pp.63-70
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• 2000

In Korea, researches for year-round leaf vegetables production system are in progress and the most of them are focused on environment control. Automation technologies for harvesting , transporting and grading need to be developed. This study was conducted to develop harvesting process automation system profitable to a competitive price. 1. Manipulator and end-effector are to be designed and fabricated , and fuzzy logic controller for controlling these are to be composed. 2. The entire system constructed is to be evaluated through a performance test. A robot system for harvesting a lettuce was developed. It was composed of a manipulator with 20DOF (degrees of freedom) an end-effector, a lettuce feeding conveyor , an air blower , a machine vision device, 6 photoelectric sensors and a fuzzy logic controller. A fuzzy logic control was applied to determined appropriate grip force on lettuce. Leaf area index and height index were used as input parameters, and voltage was used as output parameter for the fuzzy logic controller . Success rate of the lettuce harvesting system was 93.06% , and average harvesting time was about 5 seconds per lettuce.

• 한국위성정보통신학회논문지
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• 제11권2호
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• pp.60-64
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• 2016

본 논문에서는 multi-tag를 사용하는 backscatter communication에 MIMO beamforming 기술을 적용하여, 수신신호의 BER과 energy harvesting을 효율을 증대시키고자 한다. multi-tag와 Hybrid-AP(H-AP) 사이의 communication을 통해 기본 채널 정보를 얻었으며, 얻은 채널정보를 이용하여, Spatial Channel Model(SCM)의 전송 시나리오에 맞는 파라미터를 설정하고 SCM 채널을 생성하였다. 그리고 MIMO Beamforming 기술을 이용하여, H-AP는 각 tag에 SINR을 올리기 위한 optimal power를 갖는 신호를 보낸다. tag에서는 optimal power를 갖는 신호를 수신하여 backscatter communication을 수행하고, receiver에서는 multi-tag가 보내는 backscatter 신호를 수신하여 time switching 기법으로 Energy harvesting을 수행한다. 따라서 Receiver에서 energy harvesting 효율과 backscatter 신호의 BER 성능 향상을 시뮬레이션을 통해 확인할 수 있었다.

• Journal of Biosystems Engineering
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• 제19권1호
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• pp.17-21
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• 1994

This reasearch was performed to provide the fundamental intonation for the mechanization of Korean pine cone harvest when the shoot shearing method is adopted. Shear force and stress of pine cone shoots were measured and analyzed for this purpose. Samples are selected along their harvesting time and tested in 17 levels of shoot diameter from 10 to 26mm with 1mm increment. 1) Shear force-deformation characteristics showed that shoot reached its rupture point after 2 to 4 of bio-yield points. It was supposed that these multiple bio-yield points were caused by the discrete compression of wood parts which are composed of water, nutrient, resin, etc. 2) Required shear force to shear shoot was proportional to the square of shoot diamter, however, shear force for shoots of early harvesting time(Aug. 31) was proportional to the shoot diameter. Variance of shear force was increased as the harvesting time was delayed. Shear forces were distributed from 468N(Aug. 31, 12mm dia) to 4153N(Aug. 31, 26mm dia) disregarding the sampling date. 3) The average shear stresses by sampling dates were 744,822, and 883N/m2, respectively, and for the earlier shoot samples shear stress was quite smaller than the others. Shear stress was proportional to shoot diameter squared, and the effect of shoot diameter on the shear stress was decreased as harvesting time was delayed.

• 한국작물학회지
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• 제46권1호
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• pp.64-67
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• 2001

Snap bean is a new corp in Korea but believed to have a great deal of potentials for both domestic and overseas markets. The present study was performed to obtain the basic information about growth- and quality-related characteristics and to determinate the optimum seeding date and harvesting time for snap bean. Pod yield was significantly affected by seeding date. The highest pod yield was obtained from March 20 for determinate type and April 4 for indeterminate one, respectively, with the range of 13.0-23.7 t/ha. The pod length of indeterminate type was over 13cm, and the pod length was over 5 grams. The pod width for tested varieties was less than 1.0cm. Considering the pod growth characters such as pod length, pod width, and pod weight, the optimum harvesting time for immature pods of snap bean was supposed to be from 15 to 20 days after flowering. The daily yield of snap bean was begun to sharply increase from 15 days after the first flowering and the maximum yield was recorded at 30 days after flowering. For the accumulated yield, nearly 90% of total yield was obtained in 42 days after flowering.

• Journal of Communications and Networks
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• 제16권3호
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• pp.293-300
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• 2014

As energy harvesting communication systems emerge, there is a need for transmission schemes that dynamically adapt to the energy harvesting process. In this paper, after exhibiting a finite-horizon online throughput-maximizing scheduling problem formulation and the structure of its optimal solution within a dynamic programming formulation, a low complexity online scheduling policy is proposed. The policy exploits the existence of thresholds for choosing rate and power levels as a function of stored energy, harvest state and time until the end of the horizon. The policy, which is based on computing an expected threshold, performs close to optimal on a wide range of example energy harvest patterns. Moreover, it achieves higher throughput values for a given delay, than throughput-optimal online policies developed based on infinite-horizon formulations in recent literature. The solution is extended to include ergodic time-varying (fading) channels, and a corresponding low complexity policy is proposed and evaluated for this case as well.

• 한국연초학회지
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• 제14권2호
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• pp.144-150
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• 1992

This study was carried out to investigate the effect of yield and quality on the harvesting time and methods of stalk cutting in Burley Tobacco.3 harvesting methods and 4 harvesting times of stalk cutting were compared to priming. The yield and quality were high when cut the stalk after second priming in stalk curing. It was also desirable that cut the stalk after second priming in stalk curing. It was also desirable that cut the stalk on 30 days after topping for standard fertilization(N-P2O5-K2O= 17.5-17.5-35.0kg/10a) plot, and 30-35 days after topping for 30% increased fertilization.