• The Transactions of the Korean Institute of Electrical Engineers
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• v.31 no.7
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• pp.1-10
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• 1982

This paper derives the algorithm to estimate the operating cost, its marginal cost, and the reliability indices for the long term planning of power system. Treating the load duration curve and the system in the stochastic sense takes the place of the inverted load duration curve, effective load duration curve, and the numerical integration in the conventional methods. The time and accuracy of computation are substantially improved due to the fact that all expressions are represented by simple analytic form instead of the existing recursive form.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.7-12
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• 2000

The automatic turbine startup system provides turbine control based on thermal stress. During the startup, control system monitors and evaluates main components of turbine using damage mechanism and life assessment. In case of valve chest, the temperature of inner/outer wall is measured by thermo-couples and the safety of these values are evaluated by using allowable ${\Delta}T$ limit curve during the startup. Because allowable ${\Delta}T$ limit curve includes life assessment, it is possible to apply this curve to turbine control system. In this paper, low cycle fatigue damage and combined rupture and low cycle fatigue damage criterion proposed for yielding the allowable ${\Delta}T$ limit curve of CV(control valve) chest. To calculate low cycle fatigue damage, the stress analysis of valve chest has peformed using FEM. Automatic turbine startup to assure service life of CV was achieved using allowable ${\Delta}T$ limit curve.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.1
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• pp.22-30
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• 1999

This paper presents an efficient algorithm to estimate the maximum load level for heavily loaded power systems with the load-generation vector obtained by ELD (Economic Load Dispach) and/or short term load forecasting while utilizing the elliptic pattern of the P-e curve. It is well known the power flow equation in the rectangular corrdinate is jully quadratic. However, the coupling between e and f makes it difficult to take advantage of this quadratic characteristic. In this paper, the elliptic characteristics of P-e curve are illustrated and a simple technique is proposed to reflect the e-f coupling effects on the estimation of maximum loadability with theoretical analysis. An efficient estimation algorithm has been developed with the use of the elliptic properties of the P-e curve. The proposed algorithm is tested on IEEE 14 bus system, New England 39 bus system and IEEE 118 bus system, which shows that the maximum load level can be efficiently estimated with remarkable improvement in accuracy.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.9
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• pp.3087-3103
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• 2022

Nearest neighbor query in location-based services has become a popular application. Aiming at the shortcomings of the privacy protection algorithms of traditional ciphertext nearest neighbor query having the high system overhead because of the usage of the double Hilbert curves and having the inaccurate query results in some special circumstances, a privacy protection algorithm of ciphertext nearest neighbor query which is based on the single Hilbert curve has been proposed. This algorithm uses a single Hilbert curve to transform the two-dimensional coordinates of the points of interest into Hilbert values, and then encrypts them by the order preserving encryption scheme to obtain the one-dimensional ciphertext data which can be compared in numerical size. Then stores the points of interest as elements composed of index value and the ciphertext of the other information about the points of interest on the server-side database. When the user needs to use the nearest neighbor query, firstly calls the approximate nearest neighbor query algorithm proposed in this paper to query on the server-side database, and then obtains the approximate nearest neighbor query results. After that, the accurate nearest neighbor query result can be obtained by calling the precision processing algorithm proposed in this paper. The experimental results show that this privacy protection algorithm of ciphertext nearest neighbor query which is based on the single Hilbert curve is not only feasible, but also optimizes the system overhead and the accuracy of ciphertext nearest neighbor query result.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.4
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• pp.308-313
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• 2012

Robust tuning rules of the motion profile are proposed to minimize the residual vibration. For asymmetric S-curve profile, tuning rules are analytically formulated using Laplace-domain approach. When the system modeling is known exactly, by placing a single zero of the motion profile on the pole of the system, the residual vibration can be perfectly eliminated under undamped system. However, if there are some amounts of the modeling errors, the residual vibration significantly increases. To track this issue, the robust tuning rules against modeling error are discussed. One of the proposed robust tuning rules is placing the multiple zeros of the motion profile on the pole of the system, and the other is placing the zeros of the motion profile around the pole of the system. Thanks to the proposed robust tuning rules, motion profile becomes more robust to modeling errors while minimizing the residual vibration. By simulation, the effectiveness of the proposed robust tuning rules is verified.

• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.2
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• pp.21-30
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• 2007

A practical method to design the input shaping which generates control command is proposed in this paper, We suggest an experimental technique considering human operator's target tracking error to improve aiming accuracy which significantly affects hit probability. It is known that stabilization performance is one of the most important factors for ground combat vehicle system. In particular, stabilization error of the manual target tracking system mounted on moving vehicle directly affects hit probability. To reduce this error, we applied input command shaping method using preprocessing filtering and functional curve fitting. First of all, we construct the human operator model to consider effects of human operator on our system. Input shaping curve is divided into several regions to get rid of the above problems and to improve the system performance. At example design part, we chose three steps of functional command curve and determine the parameters of the function by the proposed design method. In order to verify the proposed design method, we carried out the experiments with real plant of a fighting vehicle.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.171-173
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• 1997

This study proposes a method for evaluating composite power system effective load duration curve(CMELDC) al load points. The concept of ELDC in power system planning is very useful and important in HLI as well as HLII. Effective load duration curve of composite power system can be obtained from convolution integral processing or both probability function of unarrival power and load duration curve at load points. The characteristics and effectiveness of this methodology arc illustrated by case studyings of simple system.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.1071-1074
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• 2005

The ECC(Elliptic Curve Cryptogrphics), one of the representative Public Key encryption algorithms, is used in Digital Signature, Encryption, Decryption and Key exchange etc. The key operation of an Elliptic curve cryptosystem is a scalar multiplication, hence the design of a scalar multiplier is the core of this paper. Although an Integer operation is computed in infinite field, the scalar multiplication is computed in finite field through adding points on Elliptic curve. In this paper, we implemented scalar multiplier in Elliptic curve based on the finite field $GF(2^{163})$. And we verified it on the Embedded digital system using Xilinx FPGA connected to an EISC MCU(Agent 2000). If my design is made as a chip, the performance of scalar multiplier applied to Samsung $0.35\;{\mu}m$ Phantom Cell Library is expected to process at the rate of 8kbps and satisfy to make up an encryption processor for the Embedded digital information home system.

• Journal of the Korea institute for structural maintenance and inspection
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• v.6 no.3
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• pp.119-128
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• 2002

This study discusses the issues related to the accuracy of deflection measurement and unstable energy in the testing of FRC. Some deflection methods may include large extraneous deformations. A faulty load-deflection curve will be obtained if an unstable deflection measuring system is used, and inaccurate toughness evaluation can result from this faulty curve. Some load-deflection curve of FRC may be attributed to unstable region of the load-deflection curve. If the unstable region is not correctly evaluated toughness indices from the curve would inappropriately represent true indices. In this paper, the discussion will focus on the effects of the deflection measuring system both on the measurement of the load-deflection response of FRC and the evaluation of FRC toughness and the effects of the unstable region and the management method of unstable region on toughness evaluation of FRC. It is observed that ASTM toughness indices which is based on measured deflection at first cracking is influenced significantly by extraneous deformation of deflection measurement. Extraneous deformation in deflection measurement, however result in negligible errors in toughness evaluation if JSCE and JCI definitions are used.

• The Journal of Korean Institute for Practical Engineering Education
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• v.4 no.1
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• pp.165-172
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• 2012

For practical education, many practices using various practical equipments have to be provided to students. In this study, the application of learning curve to represent student's learning process in a practical education using a equipment was studied. Learning curve model was originally developed in production management and based on human performance in human factors aspects. In this study, the application of learning curve model was studied on the eye tracking system, which is used to evaluate the usability of a product in design area. As a case study for its applicability, practical education for eye tracking system was provided to three students and then task completion times were measured for hardware system setup and gaze image recording. Learning curves were estimated for two tasks and then task completion times were predicted using the learning curves. Through ANOVA(analysis of variance) and correlation analysis, the applicability of learning curve to practical education was analysed. As the result, learning curve could be effectively applied to practical eduacation using equipment.