• Journal of KIEE
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• v.10 no.1
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• pp.7-15
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• 2000

Source separation is a statistical method, the goal of which is to separate the linear instantaneous mixtures of statistically independent sources without resorting to any prior knowledge. This paper addresses a source separation algorithm which is able to separate the mixtures of sub- and super-Gaussian sources. The nonlinear function in the proposed algorithm is derived from the generalized Gaussian distribution that is a set of distributions parameterized by a real positive number (Gaussian exponent). Based on the relationship between the kurtosis and the Gaussian exponent, we present a simple and efficient way of selecting proper nonlinear functions for source separation. Useful behavior of the proposed method is demonstrated by computer simulations.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.165-165
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• 2023

Streamflow prediction is a critical task in water resources management and essential for planning and decision-making purposes. However, the streamflow prediction is challenging due to the complexity and non-linear nature of hydrological processes. The transfer learning is a powerful technique that enables a model to transfer knowledge from a source domain to a target domain, improving model performance with limited data in the target domain. In this study, we apply the transfer learning using the Informer model, which is a state-of-the-art deep learning model for streamflow prediction. The model was trained on a large-scale hydrological dataset in the source basin and then fine-tuned using a smaller dataset available in the target basin to predict the streamflow in the target basin. The results demonstrate that transfer learning using the Informer model significantly outperforms the traditional machine learning models and even other deep learning models for streamflow prediction, especially when the target domain has limited data. Moreover, the results indicate the effectiveness of streamflow prediction when knowledge transfer is used to improve the generalizability of hydrologic models in data-sparse regions.

• The Journal of the Acoustical Society of Korea
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• v.23 no.2E
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• pp.56-67
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• 2004

Despite abundant research outcomes of blind source separation (BSS) in many types of simulated environments, their performances are still not satisfactory to be applied to the real environments. The major obstacle may seem the finite filter length of the assumed mixing model and the nonlinear sensor noises. This paper presents a two-step speech enhancement method with multiple microphone inputs. The first step performs a frequency-domain BSS algorithm to produce multiple outputs without any prior knowledge of the mixed source signals. The second step further removes the remaining cross-channel interference by a spectral cancellation approach using a probabilistic source absence/presence detection technique. The desired primary source is detected every frame of the signal, and the secondary source is estimated in the power spectral domain using the other BSS output as a reference interfering source. Then the estimated secondary source is subtracted to reduce the cross-channel interference. Our experimental results show good separation enhancement performances on the real recordings of speech and music signals compared to the conventional BSS methods.

• Journal of Biomedical Engineering Research
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• v.29 no.4
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• pp.329-336
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• 2008

Recently, causality analysis of source time series extracted from EEG or MEG signals is becoming of great importance in human brain mapping studies and noninvasive diagnosis of various brain diseases. Two approaches have been widely used for the analyses: one is independent component analysis (ICA), and the other is multiple signal classification (MUSIC). To the best of our knowledge, however, any comparison studies to reveal the difference of the two approaches have not been reported. In the present study, we compared the performance of the two different techniques, ICA and MUSIC, especially focusing on how accurately they can estimate and separate various brain electrical signals such as linear, nonlinear, and chaotic signals without a priori knowledge. Results of the realistic simulation studies, adopting directed transfer function (DTF) and Granger causality (GC) as measures of the accurate extraction of source time series, demonstrated that the MUSIC-based approach is more reliable than the ICA-based approach.

• Journal of the Korean Geographical Society
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• v.47 no.4
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• pp.625-640
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• 2012

The purpose of this study is to introduce the current status of geography education research in South Korea. This article consists of mainly two parts: 1) source of knowledge and 2) content of knowledge in geography education research. The main academic journals are introduced as the sources of knowledge. The research trends in these journals are discussed as the content of knowledge. We classified geography education research into three types based on the framework suggested by Bednarz (2000): 1) nature of geographic knowledge, learning, and curriculum, 2) teacher education in geography, and 3) strategies in the geography classroom. Relevant research regarding each category is introduced. We hope this study serves as an access point where geography educators in South Korea and other countries facilitate interactions with each other.

• Journal of KIISE:Software and Applications
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• v.29 no.1_2
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• pp.42-52
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• 2002

Information extraction(IE) is a process of recognizing and fetching particular information fragments from a document. In previous work, most IE systems generate the extraction rules called the wrappers manually, and although this manual wrapper generation may achieve more correct extraction, it reveals some problems in flexibility, extensibility, and efficiency. Some other researches that employ automatic ways of generating wrappers are also experiencing difficulties in acquiring and representing useful domain knowledge and in coping with the structural heterogeneity among different information sources, and as a result, the real-world information sources with complex document structures could not be correctly analyzed. In order to resolve these problems, this paper presents an agent-based information extraction system named XTROS that exploits the domain knowledge to learn from documents in a semi-structured information source. This system generates a wrapper for each information source automatically and performs information extraction and information integration by applying this wrapper to the corresponding source. In XTROS, both the domain knowledge and the wrapper are represented as XML-type documents. The wrapper generation algorithm first recognizes the meaning of each logical line of a sample document by using the domain knowledge, and then finds the most frequent pattern from the sequence of semantic representations of the logical lines. Eventually, the location and the structure of this pattern represented by an XML document becomes the wrapper. By testing XTROS on several real-estate information sites, we claim that it creates the correct wrappers for most Web sources and consequently facilitates effective information extraction and integration for heterogeneous and complex information sources.

• The Journal of Information Systems
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• v.11 no.1
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• pp.29-49
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• 2002

Recently the paradigm of business management has changed. The businesses have restored to ERP or BPR to integrate their information system. But now they are trying to find out a new competitiveness in tacit knowledge of individuals. The creative company has come to put much weigh on the value of their employee′s "non-patternized" knowledge. And this trend has seen a development into a theory of knowledge management in which "non-patternized" knowledge, along with explicit knowledge, is also considered as a source of competitiveness. With the hypothesis that the recognition of the knowledge management and the utilization of the information technology will have influence on the integration of the integrating the information system information system into a new phase, this study carries out a research on the effects of knowledge management and information technology on management achievement. According to this study the distribution of knowledge has an effect on the integration of information system and management achievement. The asset of knowledge, however, has little effect on them. This means that the recognition of the asset of knowledge alone can't affect the management achievement, but when combined with the recognition of the distribution of knowledge, it can have influence on the management achievement. Thus, a company has to enhance the recognition of the distribution of knowledge. And with this, a company can have a business management based on management achievement and the integration of information system utilizing information technology and the recognition of knowledge management. A company has to promote it business achievement by integrating the information system utilizing information technology and recognizing knowledge management.

• Science of Emotion and Sensibility
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• v.5 no.4
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• pp.33-43
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• 2002

The world is in the great change by the digital revolution and is changing fast to knowledge-based society beyond information society. That is to say, Knowledge is the most powerful source of competitiveness. This change of environment needs new paradigm in design. As of today, There is need to study systematically and approach practically about knowledge management. So that, we are intend to reconstruct theoretical system from design-oriented viewpoint and propose knowledge-creation paradigm through the importing technique of knowledge management into design. This study is to develop theoretical frame work of knowledge management in design as a basic study on the implementation of knowledge management for design. By the method of study for this, It was studied literature and precedent. Further more, proposed the appropriate direction of knowledge management implementation in design. Also, It was composed knowledge management system of the infra system, information system, decision-making support system and knowledge competency. Finally, The technical feature of knowledge management system was analyzed from a information technology point of view.

• Knowledge Management Research
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• v.24 no.4
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• pp.1-22
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• 2023

Knowledge management can be defined as the valuable storing and creation of new knowledge, as well as the sharing of this knowledge to be applied in all areas of an organization's management activities (Turban et al., 2003). In a knowledge-based society where intangible intellectual assets are the source of competitive advantage rather than tangible assets, knowledge management activities are emphasized in both academia and industry. This study analyzes research on "knowledge management" keyword indexed in the Korean Citation Index (https://kci.go.kr), operated by the National Research Foundation of Korea (NRF), to identify related research trends in Korea and suggest future directions for knowledge management activities. The results show that knowledge management is being researched through the integration of various fields and theories, indicating the potential for expanding research topics and fostering interdisciplinary collaboration. Furthermore, the study of knowledge management often include the keyword 'innovation', emphasizing its significant role in organizational and technological innovations. The analysis of keywords by year also reveals that they reflect the major environmental changes of each period, demonstrating the increasing importance of knowledge management in the era of the Fourth Industrial Revolution.

• Journal of Korean Library and Information Science Society
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• v.30 no.2
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• pp.155-178
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• 1999

Ciatation analysis is a information analysis method based on the phenomenon of citing previous documents in the source document. There are many well-known studies exploring citation analysis and it applications. This paper does not attempt to review this extensive area of applications, but to demonstrate the sociological aspect of citation analysis. Specifically, this paper have reviewed the citation analysis as a quantitative method for the studies of sociology of knowledge. For this, I have described various basic methods such as citation behavior, citation count, impact factor, citation relationship etc. And I have classified into four applied areas of sociology of knowledge; (1) flow of knowledge resources, (2) evaluation of knowledge resources, (3) evaluation of knowledge community, and (4) utilization in terms of knowledge policy. Finally, I have clarified the some limitations and shortcomings of citation analysis that have addressed by citation and citation analysis itself.