• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.1
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• pp.17-24
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• 2006

This study was performed to figure out spray behavior and fuel atomization characteristics of a piezo-driven injector and a solenoid-driven injector in the common-rail injection system under the same design parameters and test conditions. The process of spray injection was visualized by using the spray visualization system composed of a Nd:YAG laser and an ICCD camera. The atomization characteristics were investigated in terms of axial mean velocity, Sauter mean diameter(SMD) and droplet distributions obtained from a phase Doppler particle analyzer system. Compared with solenoid-driven injector, the piezo-driven injector has short injection delay and reaches quickly to the maximum injection value. Spray tip penetration shows some difference, however, spray angle of piezo-driven injector is wider than that of solenoid-driven injector. Sauter mean diameter of piezo-driven type injector is smaller than that of solenoid-driven type.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.202-208
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• 2008

The objectives of this study are to collect the population of each cooling system for gas and electric driven systems, and propose sample design for five cooling systems; ice storage systems, system air-conditioning system, turbo system as electric driven cooling systems, and absorption system and Gas driven Heat Pump (GHP) system as gas driven cooling systems. The sample design are carried out based on types of business, capacity, installation region and year. This study proposes criterion of the sample design for cooling systems for each energy source.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.195-200
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• 2009

The objectives of this study are to analyze of energy consumption and operation conditions of each cooling system for gas and electric driven systems, and to compare operating cost for five different cooling systems; ice storage system, system air-condition, turbo chiller as the electric driven cooling systems, and absorption chiller and Gas driven Heat Pump (GHP) as the gas driven cooling systems. The sample designs are carried out based on the types of business, capacity, installation region and year.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.945-952
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• 1994

In this paper, a mathematical model for a belt driven system is proposed to analyse the vibtation characteristics of the driving units with belts and the free and forced vibration analyses are carried out. The mathematical model for model for the belt-driven system includes belts,pulleys, spindle and bearings. Using the Hamilton principle, the 4 nonlinear governing equations and the 12 nonlinear boundary conditions are derived. To linearize and discretize the nonlinear govering equations and boundary conditions, the perturbation method and Galerkin method are used. Also, the free vibration analyses for the various parameters of the belt driven system, which are belt tension, belt length, material property of belt, belt speed and pulley mass are made. The forced vibration analyses of the system are made and the dynamic responses for the main parmeters are analysed with the belt driven system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.11
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• pp.4720-4738
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• 2015

Proper management on user-driven virtual circuits (VCs) is essential for seamless operation of virtual networks. The Network Provisioning System (NPS) is useful software for creating user-driven VCs automatically and must take fault management into account for physical layer impairments on user-driven VCs. This paper addresses a user-driven and trusty protection management in an NPS with an open standard Network Service Interface (NSI), as a contribution to show how to implement the user-driven and trusty protection management required for user-driven VCs. In particular, it provides a RESTful web service Interface for Configuration and Event management (RICE) that enable management of a distinguished data and control plane VC status between Network Service Agents (NSAs) in the event of a node or link fault and repair in a domain. This capability represents a contribution to show how network and protection events in a domain can be monitored between NSAs (NPSs with the NSI) in multiple domains. The implemented NPS controls and manages both the primary and backup VC with disjoint path in a user-driven manner. A demonstration to verify RICE API's capability is addressed for the trusty protection in the dynamic VC network.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.4
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• pp.1251-1262
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• 1996

In this paper, a mathematical model for a belt driven system is proposed to analyse the vibration characteristics of the driving units with belts and the free and forced vibraiton anlyses are carried out. The mathematical model for a belt-driven system includes belts, pulleys, spindle and bearings. By using Hamilton's principle, four nonlinear governing equations and twelve nonlinear boundary conditions are derived. To linearize and discretize the nonlinear governing equations and boundary conditions, the perturbation method and Galerkin method are used. Also, the free vibration analyses for various parameters of a belt driven system, which are the tension of a belt, the length of a belt, the material properties of belts, the velocity of a velt and the mass of pulley are made. The forced vibration analyses of the system are performed and the dynamic responses for main parameters are anlysed with a belt driven system.

• Proceedings of the IEEK Conference
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• 2001.06b
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• pp.301-304
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• 2001

The analog multiplier is very useful building block in many circuits such as filter, frequency-shifter, and modulators. In recent year, The main design issue of circuit designer is low-voltage/low-power system design, because of all systems are recommended very integrated system and portable system In this paper, the proposed the four-quadrant analog multiplier is using the bulk-driven techniques. The bulk-driven technique is very useful technique in low-voltage system, compare with gate-driven technique. therefore the proposed analog multiplier is operated in 1V supply voltage. And the proposed analog multiplier is low power dissipation compare with the others. therefor the proposed analog multiplier is convenient in low-voltage/low-power in system.

• Restorative Dentistry and Endodontics
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• v.13 no.2
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• pp.253-263
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• 1988

In order to study the cleansing effect of air-driven sonic system, the author prepared root canals on 48 extracted human permanent single rooted teeth using hand instrumentation and aforementioned method, half and half of the cases. In order for comparison of the degree of remnant debris and cleanliness, the cross sections at 3mm and 7mm levels from the apex were stereomicroscopically observed and scored in accordance with predetermined degree. The obtained results were as follows: 1. Air-driven sonic system was more effective in cleansing root canal than hand instrumentation at apical 3mm level. (p < 0.01) 2. Air-driven sonic system was more effective in cleansing root canal than hand instrumentation at apical 7mm level. (p < 0.01) 3. In hand instrumentation, Helisonic file was more effective in cleansing root canal than Rispisonic file. (p < 0.05) In air-driven sonic system, on the other hand, there were no significant difference between the two files.

• Journal of Information Technology Services
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• v.7 no.4
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• pp.231-246
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• 2008

This paper suggests an e-learning system model, a goal-driven personalized e-learning system, which increase the effectiveness of learning. An e-learning system following this model makes the learner choose the learning goal. The learner's choice would lead learning. Therefore, the system enables a personalized adaptive learning, which will raise the effectiveness of learning. Moreover, this paper proposes a SCORM standard, which modifies SCORM 2004 that has been insufficient to implement the "goal driven personalized e-learning system." We add a data model representing the goal that motivates learning, and propose a standard for statistics on learning objects usage. We propose each standard for contents model and sequencing information model which are parts of "goal driven personalized e-learning system." We also propose that manifest file should be added for the standard for contents model, and the file which represents the information of hierarchical structure and general learning paths should be added for the standard for sequencing information model. As a result, the system could sequence and search learning objects. We proposed an e-learning system and modified SCORM standards by considering the many factors of adaptive learning. We expect that the system enables us to optimally design personalized e-learning system.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.3
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• pp.351-358
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• 2006

The capability of high pressure injection with small fuel quantify at all engine operating conditions is one of the main feature in common rail fuel injection system, which is used in small and light-duty Diesel engine. The key parameter for the better atomized fuel sprays and multiple injections of this common rail fuel injection control, that can be freely selected irrespective of the engine speed and load is the mechanism controlling the needle energizing and movement in high pressure Diesel injector. In the electro-hydraulic injector, the injection nozzle is being opened and closed by movement of the injector's needle which is balanced by pressure between the nozzle seat and the needle control chamber. This study describes the macroscopic spray structure characteristics of the common rail Diesel injectors with different electric driving method i.e. the solenoid-driven and piezo-driven type. The macroscopic spray characteristics such as spray tip speed. spray tip penetration and spray cone angle were investigated by the high speed spray, which is measured by the back diffusion light illumination method with optical system for the high speed temporal photography in a constant volume chamber pressurized by nitrogen gas. As the results, the prototype piezo-driven injector system was designed and fabricated for the first time in domestic case and the effect of injector's needle response driven by different drive type was compared between the solenoid and piezo-driven injector It was found therefore. that the piezo-driven injector showed faster needle response and had better needle control capability by altering the electric input value than the solenoid-driven injector.