• Journal of Power Electronics
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• 제14권2호
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• pp.369-382
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• 2014

A growing dynamic electrical demand has created an increasing interest in utilizing nonconventional energy sources like Photovoltaic (PV), wind power, etc. In this context, this paper focuses on the design and development of a composite power controller (CPC) in the decoupled double synchronous reference frame (DDSRF) combining the advantages of direct power control (DPC) and voltage oriented control (VOC) for a PV sourced grid connected inverter. In addition, a controller with the inherent active filter configuration is tested with nonlinear and unbalanced loads at the point of common coupling in both grid connected and autonomous modes of operation. Furthermore, the loss and reactive power compensation due to a non-fundamental component is also incorporated in the design, and the developed DDSRF model subsequently allows independent active and reactive power control. The proposed developed model of the controller is also implemented using MATLAB-Simulink-ISE and a Xilinx system generator which evaluate both the simulated and experimental setups. The simulation and experimental results confirm the validity of the developed model. Further, simulation results for the DPC are also presented and compared with the proposed CPC to further bring out the salient features of the proposed work.

• The Journal of Asian Finance, Economics and Business
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• 제7권7호
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• pp.139-147
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• 2020

This paper aims to explore the relationship between the quality of the audit and the level of stock return co-movement in the context of the Vietnamese emerging market. The empirical study is designed based on the quatitative method and deductive approach. The panel dataset includes 256 listed firms from different industries,with 1115 firm-year observations on Ho Chi Minh City Stock Exchange for the period from 2014 to 2018. In the research, we built the econometric regression model, using stock return synchronicity and audit quality as the dependent and independent variable, respectively. Some control variables are also added to the econometric regression models as they are well-documented in prior research to have an effect on stock price synchronicity. To improve the accuracy of the regression coefficients, beside the Ordinary Least Squares, we employ the Random Effects Model and the Fixed Effects Model for better statistical analysis of panel data set. The results show that the quality of the audit is positively correlated to stock price synchronicity. This finding suggests that stock returns of companies with higher quality of the audit are more synchronous with the market. Results for other control variables also support our reasoning for the main findings.

• International Journal of Reliability and Applications
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• 제13권1호
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• pp.37-47
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• 2012

In this article we attempted reliability analysis of a component under the stress-strength pattern with both classical as well as Bayesian techniques. The main focus is made to develop the theory for dealing the reliability problems in various circumstances for bivariate environmental set up in context of Bayesian paradigm. A stress-strength based model describes the life of a component which has strength (Y) and is subjected to stress(X). We develop the Bayes and moment estimators of reliability of a component for each of the three possible conditions, under the assumption that the two stresses (i.e. $X_1$ and $X_2$) on a component are dependent and follow a Bivariate exponential (BVE) of Marshall-Olkin distribution, the strength of a component (Y) following exponential distribution is independent of the stresses. The simulation study is performed with Markov Chain Monte Carlo technique via Gibbs sampler to obtain the estimates of Bayes estimators of reliability, are compared with moment estimators of reliabilities on the basis of absolute biases.

• Journal of Korea Trade
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• 제24권5호
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• pp.18-34
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• 2020

Purpose - In the international shipping industry, arbitration is mainly chosen for resolving maritime disputes. This study investigates the "acceptability" of an international maritime arbitrator based on an existing theoretical model of arbitrator acceptability. Design/methodology - Using structural equation modeling techniques, this study examines a sample of senior managers who engage in the judicial affairs of their international shipping companies to verify a hypothesized model of arbitrator acceptability that covers cultural intelligence, arbitral experience, reputation, practical/legal expertise, and procedural justice as independent variables. Furthermore, the relative "perceived required time" of arbitration is tested as a moderator. Findings - Arbitrator acceptability is significantly influenced by six constructs of arbitrator characteristics: cultural intelligence, arbitral experience, reputation, practical and legal expertise, and procedural justice. Furthermore, the moderating effect of the perceived required time of arbitration is demonstrated in the relationship between arbitrator acceptability and arbitrator characteristics even though these relationships are not equally influenced. Originality/value - The originality of this study can be found in its context, that is, international maritime arbitration. Despite the potential growth of international maritime arbitration, existing studies have mainly focused on domestic arbitration. The findings of this study are expected to provide useful guidelines for nurturing international maritime arbitration in Korea.

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 2000년도 춘계 학술대회 및 국제 감성공학 심포지움 논문집 Proceeding of the 2000 Spring Conference of KOSES and International Sensibility Ergonomics Symposium
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• pp.366-369
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• 2000

This paper examines three algorithms to recognize speaker's emotion using the speech signals. Target emotions are happiness, sadness, anger, fear, boredom and neutral state. MLB(Maximum-Likeligood Bayes), NN(Nearest Neighbor) and HMM (Hidden Markov Model) algorithms are used as the pattern matching techniques. In all cases, pitch and energy are used as the features. The feature vectors for MLB and NN are composed of pitch mean, pitch standard deviation, energy mean, energy standard deviation, etc. For HMM, vectors of delta pitch with delta-delta pitch and delta energy with delta-delta energy are used. We recorded a corpus of emotional speech data and performed the subjective evaluation for the data. The subjective recognition result was 56% and was compared with the classifiers' recognition rates. MLB, NN, and HMM classifiers achieved recognition rates of 68.9%, 69.3% and 89.1% respectively, for the speaker dependent, and context-independent classification.

• 기술혁신연구
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• 제14권2호
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• pp.117-141
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• 2006

The paper describes the status and context of the Chinese Open Source Software (OSS) industry and ecosystem based on the analysis of the components of the China OSS Promotion Union. The analysis involves comparisons of several main Chinese developers of Linux operating system and makers of open source counterpart of the popular Microsoft Office package as well as several main Chinese OSS communities. Comparisons concern the technological and business aspect. The findings reveal peculiarities of the divergence of innovative activities of Chinese companies, as well as indicate that the strong government support may at the same time limit the technology selection under rigid competition, especially as foreign open source companies are found to be more focused on hobbyist developers and are able to maintain larger independent communities. Implications of the paper include the need to coordinate global development efforts and adjust science & technology policies in order to stimulate both the development and the diffusion of open source among Chinese companies and individual hobbyists.

• Journal of Multimedia Information System
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• 제3권2호
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• pp.21-26
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• 2016

Our networked world has been growing exponentially fast. The explosion in volume of machine-to-machine (M2M) transactions threatens to exceed the transport capacity of the networks that link them. Therefore, it is quite essential to reconsider the tradeoff between using many data sets versus using good data sets. We focus on this tradeoff in the context of the quality of information aggregated from many sensors in a noisy environment. We start with a basic theoretical model considered in the famous "CEO problem'' in the field of information theory. From a point of view of large deviations, we successfully find a simple statement for the optimal strategies under the limited network capacity condition. Moreover, we propose an open problem for a sensor network scenario and report a numerical result.

• 한국시뮬레이션학회논문지
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• 제1권1호
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• pp.1-16
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• 1992

This research develops two variance reduction methods for estimating the parameters of the experimental simulation model having multiple design points based on an approach focusing on reduction of the variances of the mean responses across multiple design points. The first method extends a combined approach of antithetic variates and control variates for a single design point to the multipopulation context with independent streams across the design points. The second method extends the same strategy in conjunction with the Schruben-Margolin method for improving the first method. We illustrate an example for implementing the second method. We expect these two approaches may improve the estimation of the parameters of interest compared with the control variates method.

• 한국정보과학회 언어공학연구회:학술대회논문집(한글 및 한국어 정보처리)
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• 한국정보과학회언어공학연구회 2022년도 제34회 한글 및 한국어 정보처리 학술대회
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• pp.437-441
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• 2022

문맥 독립 주장 탐지는 논점에 대한 정보가 주어지지 않은 상황에서 문서 내부의 문장들 또는 단일 문장에 대한 주장을 탐지하는 작업이다. 본 논문에서는 GCN 계층을 통해 얻은 구조 정보와 사전 학습된 언어 모델을 통해 얻은 의미 정보를 활용하는 문맥 독립 주장 탐지 모델을 제안한다. 특히 문장의 전체 구조 정보를 나타내는 부모-자식 그래프와 문장의 특정 구조 정보를 나타내는 조부모-조손 그래프를 활용해 추가적인 구조 정보를 활용하여 주장 탐지 성능을 향상시켰다. 제안 모델은 IAM 데이터셋을 사용한 실험에서 기본 RoBERTa base 모델과 비교하여 최대 2.66%p의 성능 향상을 보였다.

• 경영과정보연구
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• 제35권3호
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• pp.213-230
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• 2016

O2O(Online-to-Offline) 환경에서 기업은 온라인을 통해 고객을 유치하고 결제를 유도한 후 제품을 수령할 때에는 다시 오프라인으로 전환시키는 마케팅방식을 취함으로써 온라인과 오프라인 두 개 채널의 통합을 통한 시너지 효과를 창출하고자 한다. 이처럼 온라인과 오프라인이 공존하는 O2O 환경에서는 공급자가 제공하는 제품 및 서비스의 품질에 대한 소비자의 인지가 기존 온라인이나 오프라인 환경과는 다를 수밖에 없다. 이에 본 연구는 O2O 환경에서의 서비스 품질모델(service quality model)을 개발하고자 한다. 구체적으로 O2O는 오프라인, 온라인, 모바일 상거래가 통합된 환경인만큼 기존연구에서의 오프라인 서비스품질, 온라인 서비스품질, 모바일 서비스품질의 공통적인 서비스품질 요인을 통합하여 1차적인 O2O 서비스품질 모형을 제시한다. 다음으로 O2O 상거래를 이용하여 구매한 경험이 있는 고객을 대상으로 FGI(Focus Group Interview)를 실시하였다. 이는 1차 통합모형에서 제시된 O2O 서비스품질 요인 중 가장 중요하게 인지되는 서비스품질 요인을 규명하고, 또한 O2O만의 고유한 서비스품질 특성을 탐색하고자 하는 과정으로 1차 통합모형과 FGI를 통해 O2O 서비스 품질모델을 제시한다.