• The Korean Journal of Applied Statistics
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• v.33 no.6
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• pp.723-738
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• 2020

In this paper, we study a method to discriminate between trend stationary and difference stationary processes. Since a crucial ingredient of this discrimination is to determine the existence of unit root, we can use a unit root testing strategy. So, we introduce a discrimination based on unit root testing and propose the method using the adaptive lasso. Our Monte Carlo simulation experiments show that the adaptive lasso improves the discrimination accuracy when the process is trend stationary, but has lower accuracy than unit root strategy where the process is difference stationary.

• Journal of Digital Convergence
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• v.20 no.3
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• pp.275-281
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• 2022

This paper intends to provide a more effective understanding of the management performance (survival and growth) of startups and to suggest methods that can be applied to empirical research related to startups in the future. Therefore, in this study, the effect of entrepreneurship, trend analysis, and government support on business performance (non-financial and financial) is studied. A total of 220 questionnaires were received, and 215 were adopted except for 5 insincere questionnaires. Therefore, it was evaluated based on statistical data of 215 companies surveyed by startup officials. The questionnaire was analyzed using the SPSS 28.0 statistical program. The results of the study confirmed that all three items of the hypothesis, government support, entrepreneurship, and trend analysis of start-ups all play a positive role regardless of the difference in financial and non-financial management performance.

• Journal of the Korea Society of Computer and Information
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• v.28 no.10
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• pp.55-65
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• 2023

In this paper, we apply KeyBERT(Keyword extraction with Bidirectional Encoder Representations of Transformers) algorithm-driven topic extraction and topic frequency analysis to deep learning and reinforcement learning research to discover the rapidly changing trends in them. First, we crawled abstracts of research papers on deep learning and reinforcement learning, and temporally divided them into two groups. After pre-processing the crawled data, we extracted topics using KeyBERT algorithm, and then analyzed the extracted topics in terms of topic occurrence frequency. This analysis reveals that there are distinct trends in research work of all analyzed algorithms and applications, and we can clearly tell which topics are gaining more interest. The analysis also proves the effectiveness of the utilized topic extraction and topic frequency analysis in research trend analysis, and this trend analysis scheme is expected to be used for research trend analysis in other research fields. In addition, the analysis can provide insight into how deep learning will evolve in the near future, and provide guidance for select research topics and methodologies by informing researchers of research topics and methodologies which are recently attracting attention.

• Journal of the Korea Society of Computer and Information
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• v.29 no.1
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• pp.263-271
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• 2024

This paper analysis of spatial differences in the efficiency of regional industrial enterprises in China from 2011 to 2021. The efficiency analysis uses the DEA-CCR model. The input variables for efficiency analysis are total assets and annual average employees, and the output variables are revenue from principal business and total profits. Using trend surface analysis and gravity center model, to analysis the spatial differences of efficiency in different regions. From the results of the gravity center model, the coordinates of the gravity center of China's regional industrial enterprise efficiency in 2011 are 112.303°E & 34.239°N, and 2021 are 111.753°E & 33.791°N, which indicates that the gravity center of the efficiency of China's regional industrial enterprises in the 2011-2021 period generally moves to the southwest. From the results of the trend surface analysis, the efficiency of industrial enterprises in China's regional industrial enterprises appears to show spatial differences in both the eastwest and the northsouth directions.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.1985-1988
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• 1997

This paper comprises of details of the infrastructure issues of demonstration schemes for EVs worldwide. The aim of the paper is to highlight the different approaches being lused and to assess their effectiveness.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.27 no.1
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• pp.24-31
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• 2004

With Zohar(1980)'s research on safety climate and industrial safety, occupational safety and health literatures begin to emphasize the influence of organizational context. Based on this research trend, this paper tried to review the relationship between individual/ organizational factors and occupational accidents. Based on the responses from 643 manufacturing workers, this paper reviewed the relationship between antecedents(safety knowledge, safety motivation, safety education, and safety precaution activity) and safety consequences(accident parts, accident number, resting days). The results of statistical analysis showed that many antecedents have significantly negative relationships with safety consequences.

• Journal of the korean Society of Automotive Engineers
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• v.26 no.1
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• pp.76-82
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• 2004

In this paper, the trend of quality management system that suppliers in the automotive industry are adopting, the classification system of suppliers and car manufacturers requirements for quality are described. Due to the complexity of the requirements for quality, the introduction of an active quality management system which can meet all conditions is a difficult task. Thus, to cope with this difficulty, this paper shows the optimal requirements that suppliers have to consider when they are introducing quality management system and the discriminated strategies to assure parts quality by supplier model.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.260-264
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• 2005

This paper gives a basic information of live line maintenance technique of UHV T/L and introduce a technical background and trends of domestic and abroad. The importance of live line maintenance technology getting increased because the change of power system environment and maintenance conditions in korea. this paper explain the present state of the development of live line maintenance technique in korea and show a difference with advanced countries.

• Journal of Korean Society for Quality Management
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• v.28 no.4
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• pp.99-105
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• 2000

This paper attempts to apply Markove chain theory to literary works. the objective of this paper is to show the trend of authors and his works by way of Markovian Models. In this introductory research, it is useful to make simple criteria as virtue and evil, good and bad, justice and injustice, positive and negative, man and woman, etc. Markovian transition matrixes which are derived by M.L.E. and A.U.E are almost same. In case of Hamlet, we are able to know the author of Hamlet or his works are inconsistent and fickle.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.3
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• pp.39-47
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• 1999

This paper presents the survey of technical trend in AD converters for wireless communication systems. This paper provides explanations about the performance measure of ADC in wireless communication application and the relation ship between BER versus effective resolution and sampling speed. The survey suggests that at least one step analog frequency down conversion is required for software defined radio systems due to current technological limit.