• Korean Journal of Computational Design and Engineering
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• v.11 no.5
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• pp.327-334
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• 2006

Recently, security incidents are growing rapidly in which internal employees let the drawing leak out to competitors or other countries. This type of security incidents has a characteristic that it occurs less frequently than other types of security incidents such as network or server security incident, but the damage is a lot more serious. The existing information security technologies to prevent internal information from being leaked out are only applicable to general documents(office documents, web pages and image files in which data are encrypted one by one). However, architectural drawings made up of collection of files with various formats(extensions) have problems with the process speed of en(de) cryption and accuracy, so the developments of security technologies by new methods are required. In this study, we design and develop a security technology based on work area with which users can protect the leakage of critical information in the kernel level while maintaining their work environment when they have to use sharing information that cannot be managed by the unit of file. As a result, we developed the "Virtual Secure Disk" which allows only authorized users and applications to have an access to drawings, and have verified its security by applying it to the actual company.

• Convergence Security Journal
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• v.13 no.4
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• pp.41-46
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• 2013

Routing protocol using in the existing wire network cannot be used as it is for efficient data transmission in MANET. Because it consists of only mobile nodes, network topology is changing dynamically. Therefore, each mobile node must perform router functions. Variety of routing attack like DoS in MANET is present owing to these characteristic. In this paper, we proposed cooperative-based detection method to improve detection performance of flooding attack which paralyzes network by consuming resource. Accurate attack detection is done as per calculated adaptively threshold value considered the amount of all network traffic and the number of nodes. All the mobile nodes used a table called NHT to perform collaborative detection and apply cluster structure to the center surveillance of traffic.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.51 no.1
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• pp.18-27
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• 2002

This paper presents an implementation of digital high-performance speed sensorless control system of an induction motor drives with Direct Torque Control(DTC). The system consists of closed loop stator flux and torque observer, speed and torque estimators, two hysteresis controllers, an optimal switching look-up table, IGBT voltage source inverter, and TMS320C31 DSP controller board. The stator flux observer is based on the combined current and voltage model with stator flux feedback adaptive control for wide speed range. The speed estimator is using the model reference adaptive system(MRAS) with rotor flux linkages for speed turning signal estimation. In order to prove the suggested speed sensorless control algorithm, and to obtain a high-dynamic robust adaptive performance, we have some simulations and actual experiments at low(20rpm) and high(1000rpm) speed areas. The developed speed sensorless system are shown a good speed control response characteristic, and high performance features using 2.2[kW] general purposed induction motor.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.11
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• pp.729-736
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• 2000

This paper deals with the characteristic analysis of magnetizer for convergence purity magnet by the finite element method. The analysis utilizes combined method of the time-stepped finite element analysis and the Preisach model with hysteresis phenomena. In the finite element analysis, the non-linearity and the eddy current of the magnetizing fixure and permanent-magnet are taken account. The magnetization distribution in the permanent magnet is determined by using Preisach model which are composed of Everett function table and the first order transition curves is obtained by the Vibrating Sample Magnetometer. The calculated flux density values on the surface of the permanent magnet are led to the approximated gauss density values measured by the gauss meter. As a result, winding current, copper loss, eddy current loss of the magnetizing yoke, flux plot, surface gauss plot, temperature rise of the coil and resistor variation, vector diagram of magnetization distribution are shown.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.821-824
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• 2006

The purpose of this thesis is to grasp the actual conditions of enjoins the computer games of full 5 years old children in a kindergarten as basical datas to explore ways of program which protects overimmersion in the Internet games. we used 'The early children's actual renditions of enjoying the computer games' making up a question papers which are established questions by me based on the characteristic of research object and preceding research about diagnosis table of addicted internet in Young and passed confidence and propriety.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.147-149
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• 2005

On this study, we optimized maximizing thrust force of weight ratio and minimizing detent force of weight ratio at the TFLM(Transverse Flux Linear Motor) using design of experiments by the table of orthogonal array, characteristic function and analysis of means(ANOM), For two functions or more, the effectiveness of design change can be evaluated in accordance with change in design parameters. Also, The stator and mover weight of TFLM is reduced by up to 20 percent while its thrust force of weight ratio and detent force of weight improved. From now on, we are going to apply the required technique to design various uses and shares of the TFLM.

• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.161-164
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• 2001

This paper presents a digital speed sensorless control system for Reluctance Synchronous Motor (RSM) drives with direct torque control (DTC). The system consist of stator flux observer, rotor speed estimator, torque estimator two hysteresis band controllers, an optimal switching look-up table. IGBT voltage source inverter, and TMS320C31DSP controller by using fully integrated control software. The stator flux observer is based on the combined voltage and current model with stator flux feedback adaptive control that inputs are current and voltage sensing of motor terminal with estimated rotor angle for wide speed range. The rotor speed is estimated by the observed stator flux-linkage space vector. The estimated rotor speed can be determinated by differentiation of the rotor position used only in the current model part of the flux observer for a low speed operating area. In order to prove the suggested speed sensorless control algorithm. There are some simulation and testing at actual experimental system. The developed digitally high- performance speed sensorless control system are shown a good speed control response characteristic results and high Performance features using 1.0Kw RSM.

• Journal of the Korean Geotechnical Society
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• v.28 no.9
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• pp.23-30
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• 2012

This paper is research results of slope stability analysis associated with seepage infiltration for unsaturated soil in debris-flow occurrence slopes. Site investigations were carried out in two slopes, located at Inje in Kangwon province where debris flow occurred in 2006 and at Yangpyung in Kyeunggi province where it occurred in 2010. For unsaturated soil sampled at the zone of debris-flow initiation, soil water characteristic curves with tempe pressure cells and shear strength parameters with newly designed shear strength apparatus were obtained respectively. The commertially available software SEEP/W was used to analyze seepage infiltration in unsaturated soil, based on their properties obtained from test results and the actual rainfall data at the moment of debris flow occurrence, and slope stability analysis with the program of SLOPE/W, associated with results of seepage analysis, was performed to simulate slope failure. As results of this research, seepage infiltration to unsaturated soil due to intensive rainfall was found to cause increase of ground water table as well as degree of saturation. Through this research slope stability analysis for unsaturated soil, considering the actual rainfall characteristic, might be a reasonable method of investigating characteristics of debris flow behavior, in particular, the moment of debris flow occurrence.

• Journal of Biomedical Engineering Research
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• v.21 no.4
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• pp.411-417
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• 2000

This paper describes the analysis of the oscillometric method based on the shape of arterial pressure and proposal of a new algorithm for estimating the blood pressure by computer simulation. In the first step, the arterial pressure model which is able to control the shape of arterial pressure was designed and then we simulated the oscillometric model using both the existing exponential model showing the static arterial pressure-volume relation and the designed arterial pressure model. By analyzing the correlation of characteristic ratio based on the shape of arterial pressure, we could find that the characteristic ratio was not the only standard parameter for estimating systolic and diastolic pressure. We were able to estimate the shape of arterial pressure by computing the correlation of arterial pressure shape with oscillation shape. Finally, we proposed an algorithm which is able to estimate systolic and diastolic pressure according to pressure(Pp) table constructed from the relation of maximum amplitude of oscillation and arterial pressure shape. We tested 60 arterial pressure waveforms having various arterial pressure shape and pulse. As a results, the absolute deviation average values of the estimation of systolic, diastolic and mean pressure were 1.62%, 2.40% and 2.20%, respectively. In conclusions, the proposed algorithm showed the possibility of usefullness in estimating the blood pressure.

• Journal of Internet Computing and Services
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• v.12 no.4
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• pp.61-71
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• 2011

The Smart Network Project is planned for achieving the Internet advanced country by adjusting the Government Future Internet Development as a national agenda. The future Internet is defined as diverse alternative technology and services that can provide optimal services for individual characteristic and situation in anywhere, anytime throughout convergence of communication, broadcasting, and computing to solve the current limitation of the Internet. This paper is to analyze the economic effects of the smart network build-up. For the economic effect analysis, we reclassified the smart network industry classification system and re-drew up 2011 Inter-industry Relations Table by using the Inter-industry Relations Table issued by the Bank of Korea and the RAS techniques. And we analyzed the economic effects that can be drawn from the investment of the smart network industry. As a result, the gross production inductive effect which appears with the economic effect of the smart network establishment project from 2011 to 2015 came out to be about 72 trillion 808.2 billion KW, added value inductive effect of 44 trillion 192.9 billion KW and the employment inductive effect of the job creation of about 412 thousands people. Afterward, it is anticipated that the smart network build-up project to contribute to the improvement of Koreans' daily life. Moreover, this research will be used as a valued basic material in the pursuit of the future network projects.