• ETRI Journal
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• v.45 no.2
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• pp.213-225
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• 2023

Physical layer security (PLS) can improve the security of both terrestrial and nonterrestrial wireless communication networks. This study proposes a simplified framework for nonterrestrial cyclic prefixed orthogonal variable spreading factor (OVSF)-encoded multiple-input and multiple-output nonorthogonal multiple access (NOMA) systems to ensure complete network security. Various useful methods are implemented, where both improved sine map and multiple parameter-weighted-type fractional Fourier transform encryption schemes are combined to investigate the effects of hybrid PLS. In addition, OVSF coding with power domain NOMA for multi-user interference reduction and peak-toaverage power ratio (PAPR) reduction is introduced. The performance of $\frac{1}{2}$-rated convolutional, turbo, and repeat and accumulate channel coding with regularized zero-forcing signal detection for forward error correction and improved bit error rate (BER) are also investigated. Simulation results ratify the pertinence of the proposed system in terms of PLS and BER performance improvement with reasonable PAPR.

• Korean Journal of Clinical Pharmacy
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• v.18 no.1
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• pp.1-5
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• 2008

The goal of this research was to find out the effect of dispensing error prevention program on the incidence of the error in a university hospital pharmacy in Daegu. Dispensing error in this research was defined as the error identified during double-checking process, so it does not mean that the wrong dispensing was administered to patient. Drug name error was the most frequently found error, accounting for about one third of all dispensing errors, and was followed by counting error, strength error, dosage form error, and others. Similar drug name was identified as the most frequent reason for the error, taking up about two thirds of all drug name errors. In this research, six months of dispensing error prevention program resulted in statistically significant reduction of dispensing error by 42 percent. Therefore, it is recommended that hospital pharmacy implement such prevention program regularly to reduce the incidence of the error. Finally, it appears that drug approval authority should closely check the similar drug names and have power to command pharmaceutical company to change the name if pertinent.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.7
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• pp.891-897
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• 2013

The power system frequency plays an important role in monitoring and controlling the power system. The frequency can be measured through discrete Fourier transform (DFT) coefficients of its positive fundamental frequency. The accuracy of the frequency estimate is severely affected by noise in the power system signal and the leakage effect of the negative fundamental frequency in DFT. This paper proposes a DFT-based frequency estimation algorithm to cope with the noise as well as the leakage effect. In this algorithm, two suitable digital filters are introduced to reduce efficiently frequency estimate error due to the noise. These filters are designed to use a digital bandpass filter and a second-degree integrator. The effectiveness of the proposed algorithm in reduction of frequency estimate error is verified through simulations on noise, harmonics and frequency deviation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.4
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• pp.785-796
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• 2009

In this paper, propose for mobile robot path planning and the reduction in sleep caused by a sleep history suggested a way to compensate for record sensor error. The proposed path plan reduces the robot slip to smooth a potential barrier in the potential field method, and compensates the tachometer error by robot slip using the fuzzy logic system. The efficiency of the proposed method is verified by means of simulations and experiments for path plan and slip revision.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.12
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• pp.827-833
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• 2004

In active noise control (ANC) systems, the error-reduction performance of the conventional Filtered-X Least Mean Square (FXLMS) algorithm may be affected by nonlinear distortions in the secondary path such as in the power amplifiers, loudspeakers and transducers. In this paper, a nonlinear FXLMS algorithm with high error-reduction performance is proposed to compensate for undesirable nonlinearities in the secondary-path of ANC systems by employing the inverse Volterra filtering approach. In particular, the proposed approach is based on the utilization of the conventional P-th order inverse approach to nonlinearity compensation in the secondary path of ANC systems. Finally, the simulation results showed that the proposed approach yields a better nonlinearity compensation performance for the ANC systems with a nonlinear secondary path than the conventional FXLMS.

• Proceedings of the KIEE Conference
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• 2001.11c
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• pp.352-355
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• 2001

In this paper, we proposed measurement error reduction technique for the semiconductor device DC characteristic measurement system. Implemented system is composed of 4 SMUs, 2 VSUs, and 2 VMUs. Various efforts in hardware and software have been made to reduce the measurement errors due to the leakage current in measurement circuits. Internal and external sources of errors in measurement system especially in pA range measurement have been identified and removed. Experimental results show that the implemented system can be measure the DC characteristic of semiconductor devices in pA level.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.9
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• pp.65-72
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• 2011

A binary integration is one of sub-optimal pulse integration which decides detection based on discriminating m successful detections out of n trials in radar systems using multiple pulse repetition frequencies. This paper introduces target measurement error reduction technique to reduce azimuth errors in suboptimal binary integration radar which applies the near value by m rather than the optimal m and verifies the performance by analyzing the experimental data measured from real radar.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.608-612
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• 2000

Active control of sound radiation(using active structural acoustic control) from a vibrating rectangular plate by a steady-state harmonic point force disturbance is experimentally studied. Control structural input are achieved by two piezoceramic actuators bonded to the surface of the panel. Two accelerometers are implemented as error sensors. Estimated radiated sound signals using vibro-acoustic path transfer function are used as error signals. The vibro-acoustic path transfer function represents system between accelerometers and microphones. The control approach are based on a multi-channel filtered-x LMS algorithm. The results demonstrate that attenuation of sound levels of 3dB, 13dB are achieved.

• Communications for Statistical Applications and Methods
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• v.13 no.1
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• pp.49-60
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• 2006

There are six approaches to constructing standardized coefficient for logistic regression. The standardized coefficient based on Kruskal's information theory is known to be the best from a conceptual standpoint. In order to calculate this standardized coefficient, the coefficient of determination based on entropy loss is used among many kinds of coefficients of determination for logistic regression. In this paper, this standardized coefficient is obtained by using four kinds of coefficients of determination which have the most intuitively reasonable interpretation as a proportional reduction in error measure for logistic regression. These four kinds of the sixth standardized coefficient are compared with other kinds of standardized coefficients.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.1
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• pp.11-19
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• 1992

This paper proposes a reduced order method which reduces passband error by changing controllability and observability gramian based on weighted functions in the linear time invariant system. In the case that the 4-order model is the reduced to 3-order model in the low-pass filter, the QEI in the proposed method is improved to 6.15724 compared to 10.16464 in the balanced realization method and the sensitivity is improved to 5.45962 compared to 7.790568. The frequency property curves show that the proposed method is superior to the balanced realization method.