• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.5
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• pp.19-25
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• 2004

In this paper, we propose optimal and suboptimal serial code acquisition schemes for chip-asynchronous direct-sequence spread-spectrum systems. The conventional serial code acquisition scheme is to compare each value of correlator outputs with a threshold individually. However, such a scheme is optimum only under the chip-synchronous assumption which is actually very difficult to be held prior to acquisition at the receiver because the signal-to-noise ratios before despreading are very low. In this paper, an optimal serial code acquisition scheme is derived based on the maximum-likelihood criterion under the more realistic and general chip-asynchronous environments. A suboptimal scheme, which is simpler but yields comparable performance to the optimal one, is also derived based on the criterion of local detection power Numerical results show that, under the chip-asynchronous environments, both the optimal and suboptimal serial code acquisition schemes outperform the conventional serial code acquisition scheme.

• Journal of the Institute of Convergence Signal Processing
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• v.20 no.1
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• pp.57-62
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• 2019

In this paper, oneM2M based data monitoring and acquisition system is designed and implemented to measure and transmit the voltage, current, temperature, acceleration and vibration of the motor. The proposed system can detect electrical faults (overcurrent, reverse phase, phase loss, ground fault) and mechanical faults (MC counter, motor operation time, bearing and winding temperature, motor speed, insulation resistance). The system consists of sensor data collection, web server, php, database, wired/wireless communication system. The insulation resistance and the motor speed were measured, and the experimental results were similar for both the test resistance value and the reference input value.

• Journal of the Korean Institute of Telematics and Electronics
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• v.19 no.5
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• pp.55-67
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• 1982

In this Paper new results relating to the acquisition behavior of a class of first-and secondorder digital phase-locked loops (DPLL) originally proposed by Reddy and Cupta are presented in the absence of noise. It has been found that the number of quantization levels L and the number of phase error states N play important roles in acquisition. For a given L-level quantizer, as N increases, the acquisition time increases, and the lock range decreases. However, the deviation of the steady state phase error decreases in this case. When L increases, the acquisition time decreases, and the lock range increases. However, variation of L affects little for the steady state phase error. In addition, the effects of a loop filter on acquisition have also been considered. One can get smaller acquisition time and larger lock range as the filter parameter value becomes larger. However, deviation of the steady state phase error increases in that case. Analytical results have been verified by computer simulation.

• Journal of the Korean Society of Systems Engineering
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• v.8 no.1
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• pp.51-62
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• 2012

The System Engineering(SE) and the Earned Value Management System(EVMS), as parts of the scientific project management methodology, have been applied to Surion Helicopter R&D Program. The concept and application process of SE methodology, requirements management and applications output by DOORS program are described in this study. The concept and application process of EVMS, analysis results of schedule/cost variance for Surion RF equipment are also discussed in this study. Though the Surion R&D program is still on-going, it is found that the measures of effectiveness of SE and EVMS applications are verified.

• Asia Marketing Journal
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• v.20 no.4
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• pp.21-47
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• 2019

This study empirically examines the synergy effect of a corporate-level loyalty program on customer equity (CE) known as the lifetime value of current and future customers (Blattberg et al. 2009). A corporate-level loyalty program refers to a company-wide integration loyalty program at the corporate-level in which subsidiaries (multi-divisions) participate as program members. It does not merely examine whether there is an integration effect of a corporate-level loyalty program from the CE perspective, but it provides practical implications for a firm's strategic focus by identifying which value creation channels (i.e., acquisition, retention, and cross-selling), brand characteristics (i.e., size of the customer base before integration, diversity of products, and sales channel type), and consumer characteristics (i.e., customer relationship stage, transaction amount before integration, transaction period, and number of purchased brands) are affected the most by the synergy effect.

• English Language & Literature Teaching
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• v.13 no.3
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• pp.1-22
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• 2007

The study examined the effects of explicit derivational morphology instruction (henceforth DMI) on the incidental vocabulary acquisition and reading comprehension of 132 Korean 1st-year high school students who responded to a battery of tests (two vocabulary tests and a reading comprehension test). Multiple statistical tools were used to analyze the data: Analysis of Covariance (ANCOVA), Analysis of Variance (ANOVA), Simple Regression Analysis, Tests of Simple Main Effects, and effect size computation using Cohen's d. The results indicated that (a) DMI enhanced students' ability to infer word meanings in context, (b) DMI promoted high proficiency students' reading comprehension, whereas it impeded intermediate proficiency students' reading comprehension, (c) vocabulary knowledge has a strong positive predictive value for reading comprehension, and (d) the gaps of vocabulary knowledge across proficiency levels were still substantial, despite the observation that DMI promoted students' vocabulary acquisition. These results have a bearing on English as Foreign Language (EFL) reading pedagogy.

• Journal of electromagnetic engineering and science
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• v.5 no.1
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• pp.26-30
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• 2005

It is important to know phase offsets of PN(Pseudo Noise) sequences in spread spectrum communications since the acquisition is equivalent to making a phase offset between a receiving PN sequence and a PN sequence of local PN generator be identical. In this paper, a phase offset enumeration method for PN sequences with error detection, and its application to the synchronization are proposed. The phase offset enumeration for an n-tuple PN sequence and its error detection are performed when one period of the sequence is received. Once the phase offset of the receiving sequence is calculated, we can easily accomplish the synchronization by initializing shift registers of a local PN generator according to the phase offset value. The mean acquisition time performance of the proposed scheme was derived analytically. Since this synchronization scheme can be realized by using simple circuit and acquires very rapid acquisition in high SNR but shows performance degradation in low SNR, it can be especially useful in indoor and office environments.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.501-504
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• 2005

In general, most incomplete communication link setup between satellite and ground station right after separation from launcher come from less accurate orbital vector ground station uses to track the satellite because only predicted orbital state vector is available during first few orbits. This paper describes the developed procedure for successful initial acquisition for KOMPSAT-2 using scanning functions ofK13 antenna system with predicted orbital information. Azimuth scan, raster scan, spiral scan functions were tested with KOMPSA Tl under intentionally degraded orbital information for antenna operation. Through tests, spiral scan function was decided to be best search scan among 3 scans. Developed procedure can assure the successful acquisition only if azimuth offset and time offset value are within +/-2deg and +/-30sec, respectively.

• Korean Journal of English Language and Linguistics
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• v.1 no.3
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• pp.497-508
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• 2001

This study tested whether non-native speakers approximated native-like locus equation slopes. Russian learners of English acquired native-like values of the locus equation slope for the English bilabial, and English learners of Russian made slight modifications to the locus equation slope of the Russian bilabial. The acquisition of the locus equations occurred gradually with experience. While English speakers, with limited experience with Russian, failed to approximate Russian-typical value of the locus equations slope, Russian speakers, with more extensive experience with English, succeeded in approximating the locus equation for English bilabial. The observation of locus equation transfer effect supports for the locus equation hypothesis as the unit of acquisition over CV-by-CV learning.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.707-710
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• 2003

3kW grid-connected photovoltaic (PV) system and data acquisition system are constructed for performance analysis of PV system at field demonstration test center of Gwang-Ju in Korea. As climatic and irradiation conditions are varied, operation characteristics of the PV system are collected and analyzed in data acquisition system. From these results, the performances of PV system have simulated and evaluated using simulation tool in comparison with actual value of data acquisition system of field demonstration test center. Furthermore, performance of total PV system e.g. electric power and loss factor at the site are reviewed.