• Wind and Structures
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• v.31 no.5
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• pp.419-430
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• 2020

Weibull distribution is a conspicuous distribution known for its accuracy and its usage for wind energy analysis. The two and three parameter Weibull distributions are adopted in this study to fit wind speed data. The daily mean wind speed data of Ennore, Tamil Nadu, India has been used to validate the procedure. The parameters are estimated using maximum likelihood method, least square method and moment method. Four statistical tests namely Root mean square error, R2 test, Kolmogorov-Smirnov test and Anderson-Darling test are employed to inspect the fitness of Weibull probability density functions. The value of shape factor, scale factor, wind speed and wind power are determined at a height of 100m using extrapolation of numerical equations. Also, the value of capacity factor is calculated mathematically. This study provides a way to evaluate feasible locations for wind energy assessment, which can be used at any windy site throughout the world.

• Journal of Mechanical Science and Technology
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• v.18 no.12
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• pp.2250-2257
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• 2004

The accurate wind speed information at the hub height of a wind turbine is very essential to the exact estimation of the wind turbine power performance testing. Several methods on the site calibration, which is a technique to estimate the wind speed at the wind turbine's hub height based on the measured wind data using a reference meteorological mast, are introduced. A site calibration result and the wind resource assessment for the TaeKwanRyung test site are presented using three-month wind data from a reference meteorological mast and the other mast temporarily installed at the site of wind turbine. Besides, an analysis on the uncertainty allocation for the wind speed correction using site calibration is performed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.7
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• pp.1780-1786
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• 1995

The main goal of the present study is to establish the techniques and methodolgies of turbine performance test through evaluating the objective turbine test piece, and checking the reliability of the self-developed test facility by performing a series of turbine tests under ambient temperature condition. A high speed coupling, a lubrication system and a test bed of the test facility were modified through a series of preliminary test in order to reduce the vibration and oil leakage. The flowrate control of the test facility and data acquisition were accomplished by using a software called "Labview" The measurement of shaft horse power and control of rotational speed according to the conditions of turbine rotation were performed by a separate system. The preliminary evaluation of the measured data suggests that the developed test facility and the test technique can be used reliably for the performance test of turbines with the minor improvement.provement.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.672-675
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• 2001

In this paper, we propose that the calculation method for accurate wind speed using interpolation methods, and the finding method for accurate wind direction using interpolation polynomial, so we make better performance for 3-Cup Anemometer by the proposed methods. We embody the 3-Cup Anemometer with photo sensor to measure wind direction and wind speed. In order to more accurate wind speed and wind direction, we present the methods to overcome the limitations of system memory and of the sensor measurement error by 8 bit gray code (as substitute 360 degrees for 256 degrees data).

• New & Renewable Energy
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• v.10 no.2
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• pp.19-28
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• 2014

Wind power generation of 5 MW wind turbine was predicted by using wind measurement data from HeMOSU-1 which is at south west coast of Korea. Time histories of turbulent wind was generated from 10-min mean wind speed and then they were used as input to Bladed to estimated electric power. Those estimated powers are used in both polynominal regression and neural network training. They were compared with each other for daily production and yearly production. Effect of mean wind speed and turbulence intensity were quantitatively analyzed and discussed. This technique further can be used to assess lifetime power of wind turbine.

• Journal of Korean Society of Transportation
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• v.14 no.2
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• pp.7-29
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• 1996

Traffic flow characteristics is analysed on eight multi-lane roads which are unsignalized in urban areas. Data of traffic flow rates by classification and average speed were gathered every ten minutes interval for twenty-four hours. Machine (NC-90A) was used to acquire the field data. The major purpose of this study is to build up speed-density models on urban arterial roads. Five different kinds of models were tested. Those models are Greenshields' model, Greenberg's model, modified Greenberg's model, Underwood's model and Drake's model. The modified Greenberg's model fits best at six points and the Greenshield's model fits best two points out of eight points. The breakpoint(Kb) of modified Greenberg's model is between 10 and 32 pcphpl. Capacity drawn from speed-volume relationships were appeared to be arround 2,000 and 2,200 pcphpl at the Hannam Bridge and the Hannam Overpass and 1,100 and 1,700 pcphpl at Namsan Tunnel(No1) and the beginning point of Gyeong-Bu Expressway.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.1
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• pp.123-128
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• 2006

The proposed mathematical model of the starter-generator system incorporates the motor speed, battery voltage and the desired current to estimate the moment generation capabilities of the starter-generator and the actual current of the battery system. The fundamentals for this mathematical modeling are the simulated results of the experimental data. These pertinent data are used in establishing the governing equations for the determination of motor moments, actual battery currents and efficiencies of the system's operation at different loading characteristics and speed regions. The derived equations will be used into simulation programs to predict the fuel efficiency, vehicle characteristics of a hybrid electric vehicle equipped with a transmission starter-generator which will be developed.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2534-2536
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• 2002

This paper presents the design of high speed bit and word processor for sequence logic control using a FPGA. This FPGA is able to execute sequence instruction during program fetch cycle, because the program memory was separated from the data memory for high speed execution at 40MHz clock. Also this processor has 274 instructions set with a 32bit fixed width, so instruction decoding time and data memory interface time was reduced. This FPGA was synthesized by V600EHQ240 and Foundation tool of Xilinx company. The final simulation was successfully performed under Foundation tool simulation environment. And the FPGA programmed by VHDL for a 240 pin HQFP package. Finally the benchmark was performed to prove that the designed for bit and word processor has better performance than Q4A of Mitsubishi for the sequence logic control.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.10a
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• pp.357-360
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• 2004

Electronic Data Interchange (EDI) between a number of companies goes on increasing on the internet. Although a conventional EDI system reduces business process efforts, time, resources, etc., important information is easily and frequently exposed by well trained hackers and crackers, which inflict a severe loss on the company and even put the company under a crisis. This study integrates the conventional EDI system and Virtual Private Net (VPN) to maximize an overall efficiency of speed and security in data transaction by the level of importance. The EDI system properly interfaced to IPSec and L2TP of VPN allows us to select two modes: the one focuses on a high speed with a low or a medium level security or the other does on a high level security with a low or a medium level speed. Both the company and the end users get a lot of tangible and intangible advantages by integrating the EDI system and VPN.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.3121-3123
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• 2000

Power line communications is a topic which has been studied for many years, However. the technology has not been widely adopted for data networking in homes and small businesses due to low speed. low functionality. and other barriers. Recently. with a proper technology. it is shown that the power line infrastructure can also be served as a high-speed communications medium. This paper describes a transmission scheme for power lines that is based on orthogonal frequency division multiplex(OFDM) technique. This technique can be used for high-speed data communication over the power line. This paper also presents an adaptive tracking algorithm which allocate bits and power adaptively according to the channel characteristics. The performance of the proposed scheme has been demonstrated by some simulations with taking modeled channel conditions into account.