• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.2
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• pp.157-161
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• 1999

We investigated the effect of mechanical back side damage in Czochralski silicon wafer. The intensity of mechanical damage was evaluated by minority carrier recombination lifetime by laser excitation/microwave reflection photoconductance decay ($\mu$-PCD) technique, wet oxidation/preferential etching methods, near surface micro defect (NSMD) analysis, and X-ray section topography. The data indicate that the higher the mechanical damage intensity, the lower the minority carrier lifetime, and NSMD density increased proportionally, also correlated to the oxidation induced stacking fault (OISF) density. Thus, NSMD technique can be used separately from conventional etching method in OISF measurement.

• Journal of the Korean Society of Propulsion Engineers
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• v.13 no.1
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• pp.43-50
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• 2009

The characteristics at the intermediate operation point of the turbopump-gas generator(TP-GG) coupled test were investigated by analytical method. The pump outlet pressure, gas generator mixture ratio, gas generator pressure, and temperature were examined considering risk minimization of test. The engine system shows different behavior from the TP-GG coupled test at the intermediate operation point since the combustion pressure feeds back to the flow rate in the lines. The advanced valve changes in the combustor line helps less risky mode transition.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.7
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• pp.624-630
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• 2006

ZnO deposition parameters are not independent and have a nonlinear and complex property. To propose a method that could verify and predict the relations of process variables, neural network was used. At first, ZnO thin films were deposited by using RF magnetron sputtering process with various conditions. Si, GaAs, and Glass were used as substrates. The temperature, work pressure, and RF power of the substrate were $50\sim500^{\circ}C$, 15 mTorr, and $180\sim210W$, respectively : the purity of the target was ZnO 4 N. Structural properties of ZnO thin films were estimated by using XRD (0002) peak intensity. The structure of neural network was a form of 4-7-1 that have one hidden layer. In training a network, learning rate and momentum were selected as 0.2, 0.6 respectively. A backpropagation neural network were performed with XRD (0002) peak data. After training a network, the temperature of substrate was evaluated as the most important parameter by sensitivity analysis and response surface. As a result, neural network could capture nonlinear and complex relationships between process parameters and predict structural properties of ZnO thin films with a limited set of experiments.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.4
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• pp.154-157
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• 2006

This paper is proposed hybrid artificial intelligent(HAI) controller for high performance of induction motor drive. The design..of this algorithm based on fuzzy-neural network(FNN) controller that is implemented using fuzzy control and neural network. This controller uses fuzzy rule as training patterns of a neural network. Also, this controller uses the back-propagation method to adjust the weights between the neurons of neural network in order to minimize the error between the command output and actual output. A model reference adaptive scheme is proposed in which the adaptation mechanism is executed by fuzzy logic based on the error and change of error measured between the motor speed and output of a reference model. The control performance of the adaptive FNN controller is evaluated by analysis for various operating conditions. The results of experiment prove that the proposed control system has strong high performance and robustness to parameter variation, and steady-state accuracy and transient response.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.13 no.3
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• pp.419-427
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• 2006

Purpose: This descriptive survey was done to assess how rural women with osteoarthritis perceive their symptoms, what are their treatment preferences, and how they manage their illness. Method: Individual interviews were carried out with 205 women with osteoarthritis living in rural areas. Structured questionnaires were used and the interviewers were 7 trained research assistants. Descriptive statistics were used for data analysis with SPSS win 11.5 program. Results: Of the respondents, 68.8% were overweight and 15.1% were obese, 86.9% reported pain in the knees, low back, and shoulders and the average pain score was 66.06. Those knowing the exact diagnosis accounted for 73.7% of the respondents but only 49.7% reported receiving medical treatments, and 40.2% who received treatment adhered to their prescription. Folk medicines were used by 14.1% of the respondents, but 65.2% among them reported that folk medicines were not effective. Exercise 2.03 times per week was reported by 17.1% of the respondents and 48.6% reported preferring to walk. Conclusion: Women with osteoarthritis in rural areas need a rehabilitative care program focused on exercise. The community health care system in the rural area should deliver optimal health care for this population. The results of this study can be used as a basis for planning intervention programs for women with osteoarthritis in the rural area.

• Journal of The Korean Association of Information Education
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• v.18 no.4
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• pp.633-644
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• 2014

In this research, focusing on the public data access function and the communication function of SNS's, an educational program was implemented for the PC and mobile environments. The program offers functionality to share short messages with friends so that problems can be solved while communicating these messages back and forth. With each visiting page, a method for communication was provided, and each room had a announcements page, Q&A section, discussion forum, and file sharing space to facilitate more communication, and by adding the 'search for friends', and 'recommended friends' functionality, it was possible to study with friends and other unknown people using the program. The applications of the educational program were proposed through the analysis of survey results of elementary and high school students of the program.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.4
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• pp.521-526
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• 2015

Research on how to use the biological characteristics of human to confirm the identity of the individual is being actively conducted. Electrocardiogram(: ECG) based biometric system is difficult to counterfeit and does not cause skin irritation on the subject. It can be easily combined with conventional biometrics such as fingerprint and face recognition to give multimodal biometric systems. In this thesis, biometric identification method analysing ECG waveform characteristics from Discrete Wavelet Transform(DWT) coefficients is suggested. Feature selection is performed on the 9 coefficients of DWT using the correlation analysis. The verification is achieved by using the error back propagation neural networks. Using the proposed approach on 24 subjects of MIT-BIH QT Database, 98.88% verification rate has been obtained.

• Journal of the Korean Society of Costume
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• v.56 no.7 s.107
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• pp.68-84
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• 2006

The aim of this study is to examine a structure of trousers worn by males in the western world during the 17th and 18th centuries in order to understand the characteristics of evolution in construction. it mainly examined engravings from these era because they provided me fine and detailed portrayals of what it needed to observe. Then, it classified them into models according to each era. it supplemented a flaw of depending on single type of studying material by examining other types of historical materials such as historical paintings and documents for comparative analysis of materials and decorations and previous studies on preserved historical documents to observe the examples of structures of trousers. Secondly, it studied both historical documents and previous studies on the trousers patterns used back in those days, analyzed the characteristics of each designing method by actually draping these patterns, and observed the differences in these completed patterns to understand the characteristics of changes in fashion design skill. As for the changes in length, these patterns show only a slight difference around above and below the knee line. However, the widths of waist, hip, girth and hem were significantly altered over the years to reduce wrinkles and the cutting lines became more refined to make the clothes fit to the body. As a result, a simple but fine patterning technique was born. In particular, new methods in cutting and sewing were invented for detailed parts such as waist, pocket, front and slit.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.3
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• pp.465-471
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• 2013

Flow rate control is the uppermost concern for a trochoid hydraulic pump. Cavitation within the flow field of the pump has the greatest effect on the flow control during high-speed pump rotation of approximately 3500~4000 RPM. In this paper, based on AMESim$^{(R)}$ and Solid Works$^{(R)}$, we will present a method to simulate cavitation by analyzing the control factors of a trochoid pump, including the hydraulic pressure change at the outlet, flow rate based on the rotation speed of the inner rotor, leakage through the gap between the outer and inner rotors, and discharging angle of the outlet. The proposed methodology of the [cavitation simulation will enable field engineers to more easily design trochoid pumps, and will allow more concrete control over the flow rate of the pump by realizing an analysis model similar to the actual product model.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.8
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• pp.96-103
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• 2009

The roll forming process is commonly used for the conventional 'Fe' metal products such as a furniture drawer guide or an up-down slide guide. Recently its applications are variously expanded to the sanitary facilities or electronic devices. It is essentially required the cleanness for the high technology application and any corrosion or rust are not allowed. Therefore, in those applications the stainless steel materials are strongly demanded as the substitution of 'Fe' steel. However the mechanical properties of stainless steel are not suitable for forming process compared with those of 'Fe' steel. Up to now, the conventional F.E.M.(Finite Element Method) has been used to analyze and design the roll forming process. The purpose of this research is to obtain the proper production process and the shape of rolls to manufacture the high precision slide rails made of stainless steel material. The commercial program, SHARPE-RF, is used to analyze the entire roll forming process. The results show that the rolling process and the roll design by F.E.M. are useful from the good agreement between the shapes of products estimated by F.E.M. and those of the actual products.