• Journal of Korean Society of Transportation
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• v.13 no.4
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• pp.117-132
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• 1995

Peak-period congestion is a frequent occurrence on many freeways. Entrance-metering is an effective strategey in improving urban freeway traffic condition. This paper describes the prodecure to develop a computer program for proparing optimum ramp-metering stategies. Four existing ramp-metering optimaization models wer reviewed and evaluated in regared to their theories and actural performances. A optimization model was proposed in this paper. Final model takes aform of quadratic programming. The performance of the propeosed model wastest using FREFLO.

• Proceedings of the KIEE Conference
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• summer
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• pp.734-736
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• 2004

The main objective of this study is to applicate net metering system in residential sector. The net metering system can be considered as a kind of tariff system suitable for self generation using renewable energies in our country.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.6
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• pp.96-109
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• 2019

Roundabouts are actively installed to reduce unnecessary congestion and reduce traffic accidents. However, it is difficult to apply more than 450 cars per, hour. In addition, there is a downside to the concentration of delays in certain directions depending on traffic conditions. To compensate for these shortcomings, signal metering was introduced. Signal metering is a technique that gives red signals to adjacent left traffic flow in the event of a delay in a particular direction. The purpose of this study is comparing the effect of signal metering in conventional and special types (turbo roundabout, flower roundabout) of roundabout. VISSIM API is used for analysis. The analysis result show that only conventional roundabout signal metering algorithm reduce delay time per vehicle. As the result of the turbo roundabout and flower roundabout signal metering algorithm increase delay time per vehicle, signal metering algorithm can be applied in conventional roundabout.

• Journal of Biosystems Engineering
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• v.30 no.5 s.112
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• pp.261-267
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• 2005

In order to save labor and cost, direct seeding has been considered as an important alternative to the machine transplanting in rice cultivation. As current seeders for direct seeding of rice seeds drill irregular amount of seeds under various operating conditions, conventional drilling should be turned to precision planting which enables accurate placement of proper amount of rice seeds at equal intervals within rows. In this study, design, construction and performance evaluation of a precision seed metering device for planting of rice seeds were carried out. As prototype, the conventional roller type seed metering device was modified for planting: increasing diameter of metering roller, setting 2 or 4 seed cells on metering roller, adding seed discharging lid and its driving cam mechanism. Through performance tests for prototype and the current seed metering device, number of seeds in a hill, planting space and its error ratio, coefficient of variation of planting space (planting accuracy), and seeding length of $90\%$ of seeds in a hill divided by planting space (planting precision) at setting planting spaces of 15, and 20cm, seeding heights of 10, and 20cm, and seeding speeds of 0.1, 0.2, and 0.5m/s were investigated. Prototype showed better seed planting performance than the current seed metering devices. When setting planting space of 15 cm and seeding height of 10cm, prototype with 2 seed cells showed that variations of planting space and seeding lengths of $90\%$ of seeds in a hill at up to seeding speed of 0.5m/s were within 0.9cm, and 3.6cm, respectively.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.2
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• pp.361-367
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• 2019

Ramp metering is a traffic management technique that reduces the congestion of Expressway by controlling vehicles entering the highway. It is widely used outside the country, and Korea is also operating in seven sites (Seoul Ring Expressway). Ramp metering has the advantage of reducing congestion of Expressway, but there are disadvantages, as queuing occurs because vehicles are waiting for ramp, and the ramp queue affects adjacent roads at rush hour. To solve this problem, we improved the ramp metering algorithm to reduce the metering rate more spaces on ramp and to increase the metering rate less spaces. In order to evaluate this, the combined evaluation index was used and it was found that the result satisfied the equity and efficiency at the same time.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.3 s.168
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• pp.101-106
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• 2005

It needs to accumulate a store of know-how on the design, precision processing and appraisement for metering pump which is a kind of gear pump fer synthetic fibers. But the period and cost fur development is not effective, because designers experience many trial and error for the pump design and manufacturing process. Therefore, in order to curtail the period and cut down expenses, the analysis and simulation system is required for a designed metering pump. In this study, the pump simulation software was developed with the visual C++ language and the image processing algorithm, and was investigated through a discharge test for the planetary gear type metering pump.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1143-1147
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• 2004

A mechanical type pulsation dampener for the diaphragm metering pump has been developed. The pulsation pressure is an inevitable phenomenon for the positive displacement pump such as cam operated or solenoid operated metering pump. The pulsation pressure of the metering pump could be the noise source and would be harmful for the piping system which delivers hydraulic fluid. Developed pulsation dampener consists of three coil springs which have different spring constant and height each other. Depending on pressure magnitude of the piping system, total hydraulic pressure on damping diaphragm which compresses coil springs will be varied. Force equilibrium of the pulsation dampener will be set by manual by adjusting the compressed coil spring height. During the discharge stroke, pulsation dampener stores potential energy that is released as the pumping diaphragm back to an initial position during the suction stroke.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.2
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• pp.35-40
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• 2007

The gaseous fuel injection (GFI) type in LPG fuel supply system has more advantage than the liquified fuel injection type from the viewpoint of durability and cost reduction. But in GFI system, to control pressure and temperature of gaseous fuel is needed to get precision fuel metering for the compressible characteristic of gaseous fuel. In this study, the effects of pressure and temperature on the fuel metering was simulated by commercial flow network analysis package, Flowmaster. And the fuel composition effects on the fuel metering were also studied to figure out the fuel metering characteristics.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.246-251
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• 2000

In the present study, the analysis on heat and fluid flow in the single screw extruder is carried out by simultaneously considering the metering section and the die. The finite difference method and the finite volume method are applied to the metering section and the die, respectively. The zonal method is used to couple the metering section and the die. To investigate the effect of die on the characteristics of heat and fluid flow in the single screw extruder, the pressure back flow is included in the analysis. The screw-tip rotation is also considered by employing the quasi 3-dimensional die model. The present results are compared with the numerical and experimental data available in the literatures.

• Journal of Digital Convergence
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• v.11 no.5
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• pp.291-298
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• 2013

Metering scheme is composed of servers, clients, and an audit agency who collects the information for the clients which have been processed by servers. Although many efficient and secure metering schemes have been proposed in the literature, they do not consider the client privacy issue. To mitigate this limitation of the related work, we propose a metering scheme to protect the privacy of clients in internet. More specifically, we apply RSA based blind signature to the interaction between client and audit agency. If a client spends metering information to the server more than twice, the identity of the client is revealed by the server or audit agency.