• Journal of Korean Society of Transportation
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• v.28 no.3
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• pp.29-37
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• 2010

Ramp metering control is the most representative strategy of uninterrupted flow control and management system. Ramp metering is to adjust vehicles entering an expressway in such a way that expressway mainline maintains flow stability by regulating ramp vehicles. The effect of two metering strategies, single-entry metering and platoon metering, on mainstream under the same metering rate with pre-timed metering are analyzed by micro-simulation. Platoon metering shows lower performance than single-entry metering under the same metering rate in terms of speed, density, and delay, causes earlier breakdown than single-entry metering. It indicates that the selection of metering type has critical importance as the flow of mainline is high.

• Korean Journal of Agricultural Science
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• v.47 no.4
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• pp.829-844
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• 2020

A vacuum metering device for garlic seeds was developed, and its metering performance was tested according to the design factors. Three design factors were as follows: suction surface diameter (Edge), suction surface curvature (Type), and guide height (Guide). The suction surface curvature represents the distance between the center of the grooved suction plate and the bottom of suction plate. The metering rate and multiple metering rate were analyzed as the metering performance of the developed device with two varieties of garlic seeds: Namhae (warm region-adapted garlic) and Uiseong (cold region-adapted garlic). The best metering performance for the Namhae seeds were found with the following conditions: An Edge, Guide and Type of 40, 4, and 35 mm, respectively. In the case of the Uiseong seeds, the best conditions were as follows: An Edge, Guide and Type of 35, 4, and 30 mm, respectively. The guide height was found to be the most influential design factor on the metering performance of the metering rate and multiple rate for both Namhae seeds and Uiseong seeds. Additionally, the interaction between the area of the suction surface and the curvature of the suction surface had some effects on the multiple rate for the Uiseong seeds. It was concluded that the guide height should be 4 mm or higher so that more than 90% of the metering rate could be achieved for the tested garlic seeds with the developed metering device.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.1117-1125
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• 1996

A low-cost and precise metering device, which is suitable to automatic mixing of nutrient-solution for hydroponic culture, was developed for small-scale growers. The metering accuracy of the metering device developed was compared with commercial metering pumps. The mixing performance through the control of EC and pH was also evaluated. The accuracy of the metering device in terms of the full -scale error was $\pm$0.3% , which was much better compared to $\pm$2.45% and $\pm$1.38% for the two types of commercial metering pumps. The mixing system of nutrient-solution with the metering device showed a satisfactory control performance with the accuracies of $\pm$0.05mS/cm and$\pm$0.2pH for EC and pH, respectively.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1997.12a
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• pp.255-262
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• 1997

A low-cost and precise metering device, which is suitable to automatic mixing of nutrient-solution for hydroponic culture, was developed for small-scale growers. The metering device was composed of three parts those were supply pumps, metering cylinders and venturi tube. Those parts were controlled by personal computer with time-based odoff control method. To verify the performance of the developed metering device, the relationship between operating time and discharge was examined and the accuracy of the developed metering device was compared with commercial metering pumps. The results of this study are as follows. 1. The correlation coefficient between the flow rate and operating time was 0.9999, and the linear regression equation computed was y=21.759x, where y is the discharge(g) and x is the operating time(s). 2. The developed device has greater accuracy than commercial metering pumps in terms of the full-scale error. Calculated errors for the developed metering device and two commercial pump were $\pm$0.3 %, $\pm$2.45 % and $\pm$1.38 % respectively. 3. Above results show developed metering device is a useful tool for nutrient-solution control system.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.2
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• pp.1-11
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• 2013

This research proposed integrated expressway traffic management strategy using ramp metering and toll mainline metering. This research suggested a traffic signal optimization model for integrated operation of ramp and mainline metering based on Demand-Capacity Model that is used to optimize allowable input volume for ramp metering in FREQ model. The objective function of this model is sectional throughput volume maximization, and this model can calculate optimal signal timings for mainline metering and ramp metering. This study conducted an effectiveness analysis of integrated metering strategy using PARAMICS and its API. It targeted Seoul's Outer Ring Expressway between Gimpo and Siheung toll gate. As a simulation result, integrated operation of mainline and ramp metering provided more smooth traffic flow, and throughput volume of mainline increased to 14% in congested section. In addition, a queue of 400 meter was formed at metering point of toll gate. This research checked that integrated traffic management strategy facilitates more efficient traffic operation of mainline and ramp from diffused traffic congestion.

• Journal of Biosystems Engineering
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• v.26 no.2
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• pp.115-122
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• 2001

An impact-type seed-metering device was developed for the planting of rice-pellets. In this study, new design of pellet-metering device focused on simplicity and precision seeding for the planting of rice-seed pellets. In addition of seed-metering device, several devices were also developed such as seed-guiding device, seed-supplying tube and furrow opener for precision pellet planting. Field test was conducted to estimate the planting performance of the developed metering device. As a cam rotates, the impact bar of the metering device pushes a rice-seed pellet so that the seed can be discharged from the seed-supplying tube in the impact-type seed-metering device. Results of the tests showed that mean seeding spacing was 12cm at the traveling speed of 1.0m/s, corresponding to a target spacing for planting of rice-seed pellets. Also, both miss-seeded rate and damaged-seed rate were less than 2.0%, indicating acceptable levels for the precision planting. The developed mechanism of the impact-type metering device can be directly applied to the design of metering devices for the precision pellet planting of other crops.

• Journal of Biosystems Engineering
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• v.22 no.4
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• pp.401-410
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• 1997

Scattering of seeds is one of the problems in the hill- dropping planters with a roller-type metering device. For crops like rice, corns and beans, the hill-dropping is own better for a high yield than the drill planting. The roller type metering device has been used for the drill planters and has many advantages. However, it has a problem of scattering of seeds when they are placed on rows. In this study a method was developed to design the roller type metering device fir the precision hill-droppings. Design parameters were derived to configure completely the geometries of the roller and brush. The method was applied to the design of the metering device of the rice seeding machines. The field test showed that the metering device designed by the method made a better performance of seed placement than that made by the precvious one. The method also can be applied to the design of metering devices for the precise hill-droppings of other crops.

• Journal of Biosystems Engineering
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• v.19 no.2
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• pp.91-98
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• 1994

Planting, transplanting, and harvesting are important processes for the successful production of farm products in Korea because those require the high labor intensity during limitted period. Recently, many researches of using automatic control with a microcomputer are carried in the agricultural field, but are not much spread to the seeder development. Automatic sowing technology would be much attractive if there was a way to assure that each seed was count accurately in the seed metering device. Thus, an automatic seed metering device was designed and constructed to be controlled by microcomputer. This device could be improved in not only counting the number of seeds in but also sowing seeds between row spacings. Automatic seed metering device consisted of conveyor belt and temporary storage device. Performance of seed metering device depends on the apparatus including sensor, stepping motor and DC-solenoid. Research contents and results are summarized as follows. 1. The seed metering device involving seed hopper, sorter and temporary storage device was designed and constructed. 2. A seed counting system with six photo electric sensors, designed and built for this project, was adequate for tranferring and counting seeds accurately. 3. Operating algorithm for stepping motor and photo electric DC-solenoid was developed. The Seed metering device proved to be a smooth and accurate operating device using the algorithm. 4. The performance of second prototype metering device was examined with five kinds of seeds ; mung beans, red beans, white beans, black beans and corn to transfer and count the seeds. The error ratio of seed metering was less than 3.5%.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.417-421
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• 1996

A new concept of 22.9kV class revenue metering system based on the optical sensing technique was designed and implemented. This paper reports on the performance of a 22.9kV class three phase optical current/voltage metering scheme and three tariff metering system. This optoelectronic system was designed and developed to advance the state of the art in revenue metering. This paper deals with the characteristics of designed optical CPT (Current and Potential Transformer) and optoelectronic demand meter. The extensive field evaluation of the developed system with the existing oil filled transformer and solid state metering pair is undertaking. Upto now the operation of the optical revenue metering system under the field condition compares favorably with the existing system.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.4
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• pp.321-326
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• 2015

Smart metering is one of the most implementable internet-of-thing service. In order to implement the smart metering, a wireless communication network should be newly designed and evaluated so as to satisfy quality-of-service of smart metering. In this paper, we consider a wireless network for the smart metering implemented with multi-purpose wireless chips and channel coding-functioned micro controllers. Especially, channel coding is newly adopted to improve successful frame transmission probability. Based on the successful frame transmission probability, average transmission delay and delay violation probability are analyzed. Using the analytical results, service coverage expansion is evaluated. Through the delay analysis, service feasibility can be verified. According to our results, channel coding needs not to be utilized to improve the delay performance if the smart metering service coverage is several tens of meters. However, if more coverage is required, chanel coding adoption definitely reduces the delay time and improve the service feasibility.