• 대한교통학회지
• /
• 제28권3호
• /
• pp.29-37
• /
• 2010

도시고속도로 연결로 접속부 교통혼잡을 해결하기 위한 가장 대표적인 전략은 램프미터링 전략이다. 램프미터링 이란 고속도로의 유입램프에서 램프유입량을 조절하는 것을 말하며, 램프교통량을 제한함으로써 고속도로의 흐름을 정상 교통류로 유지시키는 것을 목적으로 한다. 본 연구에서는 램프미터링 기법중에서 고정식 미터링 방식을 기초로 하여, 동일한 미터링율이 본선에 진입할 때 차량진입방식(단일차량, 차량군)에 따라 본선 교통류에 미치는 영향을 비교분석하고 평가하고자 한다. 연결로 차량의 진입방식별 본선 교통류의 효과를 살펴본 결과, 동일한 미터링율에서 한 주기에 많은 연결로 차량들이 진입하는 다중차량진입방식이 본선교통류의 속도, 밀도, 지체 측면에서 불리한 것으로 분석되었고, 또한 교통와해가 조기에 발생하여 합류용량도 감소시키고 정체로 전이되어 낮은 속도를 갖는 것으로 나타났다. 이러한 결과들은 본선 교통량수준이 높을수록 연결로 진입방식에 따른 미터링 전략이 매우 중요하다는 것을 의미한다.

• 농업과학연구
• /
• 제47권4호
• /
• pp.829-844
• /
• 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.

• 한국농업기계학회:학술대회논문집
• /
• 한국농업기계학회 1996년도 International Conference on Agricultural Machinery Engineering Proceedings
• /
• pp.1117-1125
• /
• 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.

• 한국농업기계학회:학술대회논문집
• /
• 한국농업기계학회 1997년도 동계 학술대회 논문집
• /
• pp.255-262
• /
• 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.

• 한국ITS학회 논문지
• /
• 제12권2호
• /
• pp.1-11
• /
• 2013

본 연구에서는 램프미터링과 요금소 본선미터링을 이용한 고속도로 통합교통관리 전략을 제시하였다. 램프와 본선의 통합 미터링을 위해 FREQ에서 램프미터링 진입허용 교통량의 최적화에 사용되는 Demand-Capacity 모형을 수정하여 최적 신호시간 산정모형을 제시하였다. 본 모형은 구간별 통과교통량을 최대화하는데 목표가 있으며, 본선 요금소 및 램프의 미터링 신호시간을 결정할 수 있다. 서울외곽순환선의 김포요금소~시흥요금소 구간을 대상으로 PARAMICS와 API를 이용하여 시뮬레이션 효과분석을 시행하였다. 시뮬레이션 분석결과, 본선미터링을 통해 램프미터링 단독 운영 대비 본선을 소통원활 상태의 속도로 유지할 수 있었으며, 정체구간에서 본선의 통과교통량이 14% 개선된 결과를 나타내었다. 또한 요금소에서의 신호운영으로 400m의 대기행렬이 발생되나, 정체의 분산으로 인해 본선과 램프 모두에서 보다 효율적 교통운영이 가능함을 확인하였다.

• Journal of Biosystems Engineering
• /
• 제26권2호
• /
• pp.115-122
• /
• 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
• /
• 제22권4호
• /
• pp.401-410
• /
• 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
• /
• 제19권2호
• /
• pp.91-98
• /
• 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
• /
• 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
• /
• pp.417-421
• /
• 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.

• 전기학회논문지P
• /
• 제64권4호
• /
• pp.321-326
• /
• 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.