• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.309-310
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• 2008

In this paper, we propose a novel D-ATR (Differential-Average Transmitted Reference) scheme for UWB (Ultra Wide Band) based on impulse radio. The proposed scheme utilizing differential coding at transceiver, does not cause half loss of data rate unlike the conventional TR (Transmitted Reference) and ATR (Average TR) systems which transmit additional reference signals. In addition, the proposed scheme may provide improved BER (Bit Error Rate) performance by averaging the received reference signals like the conventional ATR. The proposed D-ATR receiver produces the averaged reference template by considering both the detected data bit and the differential coding rule.

• Journal of the Korean Society of Safety
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• v.32 no.5
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• pp.54-61
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• 2017

The purpose of this study is to develop standard reference materials for safety control of construction materials considering the required performance of standard materials including flow performance incorporating particles. The flow characteristics of concrete are very complicated depending on mixing proportions of constituent materials, admixtures, amount of mixing, type of mixer, time of mixing, temperature and so forth. Uncertainties and multidimensional properties of concrete have been evaluated through various studies but there are few researches for the development of standard reference material. In this study, based on the rheological concept, the flow performance of construction materials was evaluated to understand the properties of standard reference materials and was finally obtained representing materials which simulate the standard reference materials.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.486-488
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• 2007

The Grid Reference System, which was firstly used in SPOT series, has been successfully adapted in KOMPSAT-1 and KOMPSAT-2 program, which identifies the geographical location to make image collection plans and manage the database of satellite images. Each Grid Reference System for KOMPSAT-1 and KOMPSAT-2 was designed based on system parameters related to each KOMPSAT-1 and KOMPSAT-2 and this fact leads to the need for the design of the Grid Reference System for KOMPSAT-3 (KGRS-3, hereafter), which reflects system parameters for KOMPSAT-3. The (K, J) coordinate system has been defined as the Grid Reference System for KOMPSAT-3 using heritages from KOMPSAT-1 and KOMPSAT-2 programs. The numbering of K begins with the prime meridian of K = 1 with running eastward on earth increasingly, and the numbering of J uses a value of J = 1000 at all points on the equator and begin with running northward increasingly. The Grid Reference System for KOMPSAT-3 is to be implemented in Ground Segment of KOMPSAT-3 system.

• Journal of the Institute of Convergence Signal Processing
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• v.8 no.4
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• pp.297-306
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• 2007

Model reference control is control method such that overall response of a plant plus controller approaches that of a given reference model. The reference model provides desired trajectory the plant should follow. There are many kinds of control methods in MRC. However, this paper focuses on Model Reference Sliding Mode Control. The plant of these controls is an uncertain and linear system varying in time, of second order, and with SISO. In this paper, a design scheme of reference model is proposed for MRSMC. The scheme determines reference model based on the information on bounded control inputs, reference inputs and system parameters. It is used to choose a Fixed Reference Model in the process of controller design, to update Variable Reference Model when stepwise reference inputs change and to update Instant Reference Model at every sampling time. The simulation results show that the proposed method yields better control performance than the conventional MRC subject to the stepwise reference input when applied to the position control system for motor system.

• Nutritional Sciences
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• v.6 no.3
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• pp.185-188
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• 2003

The Dietary Reference Intakes which were developed by the Food and Nutrition Board, National Academy of Sciences of the United States, and Health Canada provide a good deal of information on nutritional requirements which apply to Korea. In addition, the processes of evidence based review of information on nutrient needs, dietary excess, and the assessment and planning of dietary intakes may be useful in Korea as well as North America. However, other aspects of the Dietary Reference Intakes may not be appropriate. This article discusses these issues.

• Journal of the Korean Data and Information Science Society
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• v.17 no.4
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• pp.1387-1395
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• 2006

This paper considers testing for the ratio of two exponential means. We propose a solution based on a Bayesian decision rule to this problem in which no subjective input is considered. The criterion for testing is the Bayesian reference criterion (Bernardo, 1999). We derive the Bayesian reference criterion for testing the ratio of two exponential means. Simulation study and a real data example are provided.

• Journal of Power System Engineering
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• v.11 no.3
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• pp.66-72
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• 2007

This study proposed new method to decide the reference model necessary for design PID controller. In generally, control design problems using the reference model have the following two factors. One factor is that numerical model of the controlled system can be obtained extremely, and the other is that specification for the closed-loop dynamic performance is pure moderate. Therefore, the control design procedure is essentially based on the partial reference model matching which offers a reasonable method to simplify the design and the controller configuration under the controlled system uncertainty. ITAE(Integral of time-multiplied absolute error) performance index and Kitamori method etc. which were used a reference model method had a limit to settling time and rising time of reference model that it arrived to steady state response according to the controlled system. On this study, if it only knew peak time of overshoot and settling time by measurement signal of the controlled system, it can be made the reference model easily. We proposed new method to improve performance index of the reference model superior to existing reference model index and illustrate the numerical simulation results to show the effectiveness of proposed control method design.

• Journal of Power Electronics
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• v.18 no.5
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• pp.1398-1408
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• 2018

In order to further improve the steady-state control performance of model predictive torque control (MPTC), a double-vector-based model predictive torque control without a weighting factor is proposed in this paper. The extended voltage vectors synthesized by two basic voltage vectors are used to increase the number of feasible voltage vectors. Therefore, the control precision of the torque and the stator flux along with the steady-state performance can be improved. To avoid testing all of the feasible voltage vectors, the solution of deadbeat torque control is calculated to predict the reference voltage vector. Thus, the candidate voltage vectors, which need to be evaluated by a cost function, can be reduced based on the sector position of the predicted reference voltage vector. Furthermore, a cost function, which only includes a reference voltage tracking error, is designed to eliminate the weighting factor. Moreover, two voltage vectors are applied during one control period, and their durations are calculated based on the principle of reference voltage tracking error minimization. Finally, the proposed method is tested by simulations and experiments.

• Journal of the Korean Society for Railway
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• v.12 no.5
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• pp.694-699
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• 2009

This paper presents a synchronous-reference-frame-based control of single-phase UPQC(Unified Power Quality Conditioner) to improve power quality in ac electrified railway systems. The proposed synchronous-reference-frame-based UPQC can compensate the voltage distortion, the voltage sag, the harmonic currents, and the reactive power instantaneously. The simulation results show that the UPQC can compensate the harmonic supply voltages, the voltage sag, the harmonic load currents, and the reactive power in electrified railway systems. Validity and effectiveness of the proposed UPQC control method based on the synchronous-reference-frame is illustrated through the simulation results.

• The Journal of the Acoustical Society of Korea
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• v.27 no.5
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• pp.221-228
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• 2008

To estimate array shape with reference sources in SONAR systems, nearfield signal modeling is required for the reference sources near a towed array. Array shape estimation method based on the nearfield signal modeling generally exploits the spatial covariance matrix of the received reference sources. Among those method, nearfield eigenvector method uses the eigenvector corresponding to the maximum eigenvalue as a steering vector of the reference source. In this paper, we propose a simplified subspace fitting method based on the nearfield signal modeling with spherical wave modeling. Furthermore, we analyze performance of the array shape estimation methods based on the nearfield signal modeling for various environments. The results of the numerical experiments indicate that the simplified subspace fitting method and the nearfield eigenvector method with single reference source shows almost similar performance. Furthermore, the simplified subspace fitting method with 2 reference sources consistently estimates the shape of the array regardless of the incident angle of the reference sources, whereas the nearfield eigenvector method cannot apply for the case of 2 reference sources.