• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.555-560
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• 2003

Korean High Speed Train(KHST) has been tested on the high speed test line in Osung site of Korea High Speed Rail Construction Authority (KHRC). since it was developed as G7 Project Plan In 2002. This paper introduces the dynamic test devices in KHST and shows the comparison between the results of test and theoretical computing results which derive from the new model for KHST dynamic behavior. Previous computer simulation model for KHST was developed to review wether the vehicle system was satisfied with the dynamic performance requirements during the design procedure. But It should be applied the results of the parts test for suspension elements in order to compare between the results of computation and real test. Using VAMPIRE Program made by AEA Technology in UK. the new model also was modified. This paper shows that the static wheel loads calculated from new model is similar to test results. For test on high speed line, we prepared the test devices for evaluating the dynamic performances. which was consisted of the accelerometers( based on Kisler Co.) and the data aquisition systems (based on National instrument Co.), and test program coded by LabView 6i program. These lest devices and programs are flexible to extension the channels for adding sensors and connect to the ethernet network. The acceleration of car bodies, bogie frames and axle boxes were compared between the results of computation and test at 150km/. This paper shows that the results of test were high in high frequency band range but similar frequency band range. It might be considered that these differences were caused by the test which did not performed at constant speed for comparison analysis. Also. It will be able to understand the differences and make better results through a lot of tests planed in future.

• Journal of The Korean Association of Information Education
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• v.19 no.4
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• pp.467-480
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• 2015

According to the 2015 Revised Curriculum, elementary school students will study software education for only 17 hours. Under these guidelines, it is impossible for student to achieve the objectives of software education. Therefore, we developed the software education curriculum model for elementary schools. After analyzing international and domestic trend in software education curricula, we developed a framework for software education that is divided into three parts: software, computer systems, and fusion activity. Each part has seven, color-coded levels that resemble a rainbow. This allows students to move to the next level after completing the achievement goals of the previous level, regardless of their grade. We expect that this model will be used in the future to develop textbooks, teaching materials, and tools for software education.

• The Journal of Information Systems
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• v.29 no.1
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• pp.75-91
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• 2020

Purpose Retrofit, defined to be addition of new technologies or features to the old system to increase efficiency or to abate GHG emissions, is considered as an important alternative for the old coal-fired power plant. The purpose of this study is to propose mathematical method to model multiple alternative retrofit in Generation Capacity Expansion Planning(GCEP) problem, and to get insight to the retrofit patterns from realistic case studies. Design/methodology/approach This study made a multi-alternative retrofit GECP model by adopting some new variables and equations to the existing GECP model. Added variables and equations are to ensure the retrofit feature that the life time of retrofitted plant is the remaining life time of the old power plant. We formulated such that multiple retrofit alternatives are simultaneously compared and the best retrofit alternative can be selected. And we found that old approach to model retrofit has a problem that old plant with long remaining life time is retrofitted earlier than the one with short remaining life time, fixed the problem by some constraints with some binary variables. Therefore, the proposed model is formulated into a mixed binary programming problem, and coded and run using the GAMS/cplex. Findings According to the empirical analysis result, we found that approach to model the multiple alternative retrofit proposed in this study is comparing simultaneously multiple retrofit alternatives and select the best retrofit satisfying the retrofit features related to the life time. And we found that retrofit order problem is cleared. In addition, the model is expected to be very useful in evaluating and developing the national policies concerning coal-fired power plant retrofit.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.4
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• pp.260-267
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• 2017

Quantum-inspired Genetic Algorithm (QGA) is a probabilistic search optimization method combined quantum computation and genetic algorithm. In QGA, the chromosomes are encoded by qubits and are updated by quantum rotation gates, which can achieve a genetic search. Asset-based weapon target assignment (WTA) problem can be described as an optimization problem in which the defenders assign the weapons to hostile targets in order to maximize the value of a group of surviving assets threatened by the targets. It has already been proven that the WTA problem is NP-complete. In this study, we propose a QGA and a hybrid-QGA to solve an asset-based WTA problem. In the proposed QGA, a set of probabilistic superposition of qubits are coded and collapsed into a target number. Q-gate updating strategy is also used for search guidance. The hybrid-QGA is generated by incorporating both the random search capability of QGA and the evolution capability of genetic algorithm (GA). To observe the performance of each algorithm, we construct three synthetic WTA problems and check how each algorithm works on them. Simulation results show that all of the algorithm have good quality of solutions. Since the difference among mean resulting value is within 2%, we run the nonparametric pairwise Wilcoxon rank sum test for testing the equality of the means among the results. The Wilcoxon test reveals that GA has better quality than the others. In contrast, the simulation results indicate that hybrid-QGA and QGA is much faster than GA for the production of the same number of generations.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.12 s.354
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• pp.1-8
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• 2006

In this paper, we propose carrier phase synchronization algorithm which are base on turbo coded system for DVB-RCS. There have been two categories of phase estimator, single estimator outside turbo code decoder and multiple estimators inside turbo code decoder. In single estimator, we use the estimation algorithm that ML(Maximum Likelihood) and LMS(Least Mean Square), also three different soft decision methods are proposed. Multiple estimator apply PSP(Per Survivor Processing) algorithm additionally. We compared performance between single estimator and Multiple estimator in AWGN channel. We presented the two methods of PSP algorithm for performance elevation. First is the Bi-directional channel estimation and second is binding method.

• Korean Journal of Child Studies
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• v.36 no.5
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• pp.75-94
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• 2015

This study examined short-term longitudinal reciprocal relationships between maternal parenting behavior and preschoolers' compliance/noncompliance, as well as stability in both maternal parenting behavior and preschoolers' compliance/noncompliance over time. The sample which was used for this study was taken from a two-wave (one year apart) longitudinal study of preschool-aged children and their mothers (N = 53 dyads). At both times, mothers and their children were invited to a laboratory and engaged in 25 minutes of play involving three episodes of mother-child interaction. Maternal parenting behavior and preschoolers' compliance/noncompliance during play were coded using the Dyadic Parent-Child Interaction Coding System-III (DPICS-III). Maternal codes included positive, neutral, and negative parenting behaviors and child codes were comprised of compliance and noncompliance. The results revealed that during the play session, maternal neutral and negative parenting behavior and preschoolers' compliance were stable over time. In addition, T1 maternal negative parenting behavior was significantly related to T2 child compliance/noncompliance. However, T1 child compliance/noncompliance were not significantly associated with T2 maternal parenting behavior. These findings suggest that during the preschool period, there are unidirectional effects from mothers to children.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.3A
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• pp.225-234
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• 2008

Orthogonal Frequency Division Multiplexing (OFDM) systems utilizing direct conversion receiver suffer from frequency selective (FS) and frequency independent (FI) phase and gain imbalances caused by imperfect local oscillator and low pass filter. In this paper, we analyze the impacts of the transmit/receive IQ imbalances on the system and propose the estimation and compensation schemes for those imbalances. The preamble signals coded by Alamouti scheme in the frequency domain could be used in the estimation of relatively large IQ imbalances with FS and FI characteristics and the estimation results are used for the compensation of distortions caused by the FI and FS IQ imbalances. The optimal maximum likelihood (ML) receiver or suboptimal ordered successive interference cancallation (OSIC) receiver utilizing the estimation results show symbol error rate (SER) performance improvement compared to zero-forcing (ZF) technique due to diversity gain inherent in the frequency domain IQ imbalances combined with the frequency selective channels.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.5C
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• pp.479-486
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• 2010

In this paper, we propose a novel low-complexity Alamouti coded orthogonal frequency division multiplexing (OFDM) scheme for asynchronous cooperative communications. Exploiting the combination of OFDM symbols at the source node and simple operations including sign change and complex product at the relay node, the proposed scheme can achieve cooperative diversity gain without use of time-reversion and shifting operations that the conventional scheme proposed by Li and Xia needs. In addition, by using the cyclic prefix (CP) removal and insertion operations at the relay node, the proposed scheme does not suffer from a considerable degradation of bit-error-rate (BER) performance even though perfect timing synchronization is not achieved at the relay node. From the simulation results, it is demonstrated that the BER performance of the proposed scheme is much superior to that of the conventional scheme in the presence of timing synchronization error at the relay node. It is also shown that the proposed scheme obtains two times higher diversity gain compared with the conventional scheme at the cost of half reduction in transmission efficiency.

• The Korean Journal of Franchise Management
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• v.12 no.2
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• pp.35-49
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• 2021

Purpose: The major objective of this study is to develop a model for the impact of franchisors' Gapjil (verbal·nonverbal Gapjil, abusing bargaining position, refusing transaction, false or exaggerated information, restrictive practices, unfair damage compensation) on franchisee's recontract intention. We also examine the mediating role of economic satisfaction and social satisfaction in the relationship between franchisors' Gapjil and franchisee's contract intention. Research design, data, and methodology: Data were collected from franchisee owners located nationwide in Korea. Out of 256 questionaires distributed, a total of 256 questionnaires were returned. After excluding 10 invalid respondent questionnaires, we coded and analyzed 246 valid questionnaires (effective response rate of 96.09%) using frequency, confirmatory factor analysis, correlations analysis, and structural equation modeling with SPSS 22.O and SmartPLS 3.0. Results: The findings of this study are summarized as follows: First, among the Gapjil of the franchisors, restrictive practices and unfair damage compensation had negative effects on economic and social satisfaction, but verbal and nonverbal Gapjil for economic and social satisfaction was not significant. Second, abusing bargaining positions and false or exaggerated information had negative effects on social satisfaction, but for economic satisfaction, found to be insignificant. Third, economic and social satisfaction had positive effects on the franchisee's recontract intention to the franchisor. Conclusion: The following implications of this study are as follows. First, the construct of Gapjil that occurs between the franchisors and the franchisees was first presented, and the franchisors' Gapjil is divided into interpersonal Gapjil and structural Gapjil. Second, the Gapjil of the franchisors can be an important predictor variable in maintaining and developing a long-term relationship between the franchisors and the franchisees. Third, solving conflict due to the Gapjil problem between franchisors and franchisees can be an important factor for franchisors and franchisees to co-survive and thrive in Korean franchise system. Fourth, this study suggest that managing the Gapjil of the franchisors was a important antecedent factor in maintaining long-term relationship between the franchisors and the franchisees. Therefore, this study will help franchisors formulate effective symbiotic marketing strategies to satisfy relationships with franchisees and consequently enhance long-term orientation.

• Journal of Biomedical Engineering Research
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• v.42 no.4
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• pp.175-185
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• 2021

Purpose: Vital sign are used to help assess the general physical health of a person, give clues to possible diseases, and show progress toward recovery. Researchers are using vital sign data and AI(artificial intelligence) to manage a variety of diseases and predict mortality. In order to analyze vital sign data using AI, it is important to select and extract vital sign data suitable for research purposes. Methods: We developed a method to visualize vital sign and early warning scores by processing retrospective vital sign data collected from EMR(electronic medical records) and patient monitoring devices. The vital sign data used for development were obtained using the open EMR big data MIMIC-III and the wearable patient monitoring device(CareTaker). Data processing and visualization were developed using Python. We used the development results with machine learning to process the prediction of mortality in ICU patients. Results: We calculated NEWS(National Early Warning Score) to understand the patient's condition. Vital sign data with different measurement times and frequencies were sampled at equal time intervals, and missing data were interpolated to reconstruct data. The normal and abnormal states of vital sign were visualized as color-coded graphs. Mortality prediction result with processed data and machine learning was AUC of 0.892. Conclusion: This visualization method will help researchers to easily understand a patient's vital sign status over time and extract the necessary data.