• Journal of Positioning, Navigation, and Timing
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• v.5 no.4
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• pp.213-219
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• 2016

Most existing studies on the wide-area differential global positioning system (WADGPS) employed a grid ionosphere model for error correction in the ionospheric delay. The present study discusses the application of satellite-based ionospheric delay model that provides an error model as a plane function with regard to individual satellites in order to improve accuracy in the WADGPS. The satellite-based ionospheric delay model was developed by Stanford University in the USA. In the present study, the algorithm in the model is applied to the WADGPS system and experimental results using measurements in the Korean Peninsula are presented. Around 1 m horizontal accuracy was exhibited in the existing planar fit grid model but when the satellite-based model was applied, correction performance within 1 m was verified.

• Textile Coloration and Finishing
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• v.20 no.5
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• pp.7-13
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• 2008

In order to introduce new functions onto textile fabrics, nylon and cotton were treated with green tea extracts. And then the anti-oxidant activity of fabrics treated with the extracts was evaluated by Blois method using DPPH ($\alpha$, $\alpha$-diphenyl- $\beta$-picrylhydrazyl). The anti-oxidant activity was exhibited on the textile fabrics treated as well as by the extracts itself. The cotton fabric treated with 10% o.w.f. of extract appeared to have almost 90% of anti-oxidant activity and 95% was obtained for nylon.

• Steel and Composite Structures
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• v.9 no.5
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• pp.445-455
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• 2009

This study proposes a system identification technique for a fiber-reinforced polymer deck with neural networks. Neural networks are trained for system identification and the identified structure gives training data in return. This process is repeated until the identified parameters converge. Hence, the proposed algorithm is called an iterative neural network scheme. The proposed algorithm also relies on recent developments in the experimental design of the response surface method. The proposed strategy is verified with known systems and applied to a fiber-reinforced polymer bridge deck with experimental data.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.5
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• pp.54-60
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• 2013

There is increasing demand for practical groundings for small-area substations because of the recent revision of Korea's Electrotechnical Regulations, which necessitates the method of evaluating their safety. This paper proposes a practical mesh grounding system for 22.9kV substations and studies how to evaluate its safety. The proposed grounding system is proved to obey the safety criteria of ANSI/IEEE Std. 80 via ANSI/IEEE Std. 80 method and computer simulation.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1143-1145
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• 2000

In this paper, it presents the design and implementation of a Microstep control IC using Programmable Logic Device(PLD). A Microstep driver is implemented with a 5-phase hybrid stepping motor, which has a Pentagon winding, power MOSFETs, and some devices to improve the system characteristics. The Microstep driving method is used for high performance motion control, low vibration and low noise in motor control system. The improvement of the electrical and mechanical driving characteristic of a step motor is achieved by applying microstep driver.

• Proceedings of the KIEE Conference
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• 1994.11a
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• pp.124-129
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• 1994

We have developed a stabilizing SMES with 0.5MJ energy storage capacity through all the research process of the system planning, magnet drawing, which including various kinds of evaluation for the optimized system organization. This research performance is considered to be very distinguished one. Besides, the acquired knowledge and many experiences getting through the performance of the study are much benefitful to other studies concerning with a development of superconducting electrical power machines. This paper gives the general presentation of the study and many kindes of expermental results including analysis of them.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.5
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• pp.829-836
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• 2017

This paper is a study on development of a new structured AMR/AMI(automatic meter reading/advance metering infrastructure) system. The developed system has a faster reading and is cheaper and easier to install compared to the existing AMR/AMI system. The system can be applied to AMR/AMI for five kinds of meters, electricity, gas, water, hot-water and calorie meter, which are used in most Korean households. Test results show that the developed system is both economical and reliable both in theoretical and practical applications. The resuts also show that the developed system is more suitable than existing system for AMR/AMI applications.

• Economic and Environmental Geology
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• v.40 no.6
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• pp.833-841
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• 2007

The groundwater heat pump system(GWHP) is one of the most efficient ground source heat pump system(GSHP) which uses low grade and shallow geothermal energy for cooling and heating purpose. The GWHP system shall be designed properly based on peak block load performance and optimum pumping rate of groundwater comparable to ground coupled heat pump system(GCHP). The optimum pumping rate depends on groundwater temperature at a specific site, size of plate heat exchanger, and total head loss occurred by whole system comprising pumps and pipings. The required optimum flow rates of the system per RT are ranged from 3.8 to 9.8lpm being less than the typical building loop flow of 9.5 to 11.4lpm.

• Journal of Biosystems Engineering
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• v.35 no.2
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• pp.77-84
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• 2010

In this study, we tried to predict tractor power output, fuel consumption rate and work performance indirectly in order to develop an eco driving system. Firstly, we developed equations which could predict tractor power output and fuel consumption rate using characteristic curves of tractor power output. Secondly, with actual engine rpm determined by initial engine rpm and work load, tractor power output and fuel consumption rate were forecasted. Thirdly, with speed signals of GPS sensor system, it was possible to foresee tractor work performance and fuel consumption rate. Lastly, precision of the eco driving system was evaluated through tractor PTO test, and effects of the eco driving system were investigated in the plowing and rotary tilling operations. Engine rpm, power output, fuel consumption rate, work performance and fuel consumption rate per plot area were displayed in the eco driving system. Predicted tractor power outputs in the full load curve were well coincided with the actual power output of prototype, but small differences, 1 to 6 ㎾, were found in the part load curve. Error of the fuel consumption rate was 0.5 L/h, 4.5%, the greatest, and 1 to 3 L/h at the part load curve. It was shown that 69% and 53% of fuel consumption rates could be reduced in plowing and rotary tilling operations, respectively, when the eco driving system was installed in tractor.

• Journal of information and communication convergence engineering
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• v.5 no.2
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• pp.136-139
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• 2007

In this paper we will discuss a general idea about an information system which provides information a user really needs in user's authentication. We will discuss how RFID could be applied for this kind of system especially from the standpoint of using RFID as a way to collect information of personal belongings. Also we will discuss security issues of using RFID as a component of the proposed system because while RFID could provide usefulness, it could also be very dangerous for revealing private information without user's awareness.