• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.10
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• pp.1422-1432
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• 1993

Nonlinear mapping function of the HCNN( Hidden Control Neural Network ) can change over time to model the temporal variability of a speech signal by combining the nonlinear prediction of conventional neural networks with the segmentation capability of HMM. We have two things in this paper. first, we showed that the performance of the HCNN is better than that of HMM. Second, the HCNN with its prediction error measure given by weighted distance is proposed to use suitable distance measure for the HCNN, and then we showed that the superiority of the proposed system for speaker-independent speech recognition tasks. Weighted distance considers the differences between the variances of each component of the feature vector extraced from the speech data. Speaker-independent Korean digit recognition experiment showed that the recognition rate of 95%was obtained for the HCNN with Euclidean distance. This result is 1.28% higher than HMM, and shows that the HCNN which models the dynamical system is superior to HMM which is based on the statistical restrictions. And we obtained 97.35% for the HCNN with weighted distance, which is 2.35% better than the HCNN with Euclidean distance. The reason why the HCNN with weighted distance shows better performance is as follows : it reduces the variations of the recognition error rate over different speakers by increasing the recognition rate for the speakers who have many misclassified utterances. So we can conclude that the HCNN with weighted distance is more suit-able for speaker-independent speech recognition tasks.

• The KIPS Transactions:PartB
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• v.12B no.7 s.103
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• pp.829-840
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• 2005

Word Sense Disambiguation(WSD) is one of the most difficult problem in Korean information processing. We propose a WSD model with the capability to filter semantic information using the specific characteristics in dictionary dictions, and nth added information, useful to sense determination, such as statistical, distance and case information. we propose a model, which can resolve the issues resulting from the scarcity of semantic information data based on the word hierarchy system (thesaurus) developed by Ulsan University's UOU Word Intelligent Network, a dictionary-based toxicological database. Among the WSD models elaborated by this study, the one using statistical information, distance and case information along with the thesaurus (hereinafter referred to as 'SDJ-X model') performed the best. In an experiment conducted on the sense-tagged corpus consisting of 1,500,000 eojeols, provided by the Sejong project, the SDJ-X model recorded improvements over the maximum frequency word sense determination (maximum frequency determination, MFC, accuracy baseline) of $18.87\%$ ($21.73\%$ for nouns and inter-eojeot distance weights by $10.49\%$ ($8.84\%$ for nouns, $11.51\%$ for verbs). Finally, the accuracy level of the SDJ-X model was higher than that recorded by the model using only statistical information, distance and case information, without the thesaurus by a margin of $6.12\%$ ($5.29\%$ for nouns, $6.64\%$ for verbs).

• Journal of Broadcast Engineering
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• v.15 no.1
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• pp.122-132
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• 2010

AT-DMB system has been developed to increase data rate up to double of conventional T-DMB in the same bandwidth while maintaining backward compatibility. The AT-DMB system adopted hierarchical modulation which adds BPSK or QPSK signal as enhancement layer to existing DQPSK signal. The enhancement layer signal should be small enough to maintain backward compatibility and to minimize the coverage loss of conventional T-DMB service coverage. But this causes the enhancement layer signal of AT-DMB susceptible to fading effect in transmission channel. A turbo code which has improved error correction capability than convolutional code, is applied to the enhancement layer signal of the AT-DMB system for compensating channel distortion. However there is a need for other solutions for better reception of AT-DMB signal in receiver side without increasing transmitting power. In this paper, we propose adaptive array antenna system with Eigen-space beamforming algorithm which benefits beamforming gain along with diversity gain. We analyzed the reception performances of AT-DMB system in indoor and mobile environments when this new smart antenna system and algorithm is introduced. The computer simulation results are presented along with analysis comments.

• The Transactions of the Korea Information Processing Society
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• v.7 no.11S
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• pp.3702-3713
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• 2000

Telecommunications standards have two different types of regulations: one is a law. enacted by government which all telecommunications related industries must observe. The other is a recommendatory standards. formulated by either government agency or some standardization organizations. Observation of these standards is not obligatory. However, technical standards are strict laws and ordinances based on common judgement and various conditions for evaluation of levels and limits. This paper deals with enhancing productivity of enactment and revision of technical standards. Through database of above related information we secure information continuity and public property of cyber space for the public. In this paper. we also classify recent data within the website in and out of the country offering four different methods of information retrieval and management system. The four retrieval methods suggested in this paper are itemized keyword retrieval. hierarchical retrieval, regulatory keyword retrieval and chronological keyword retrieval. These various retrieval methods provide the public with information of enactment and amendment of laws and regulations in the cyber space. thereby guarantees the sharing of information. Finally the important feature of the information retrieval system implemented in this paper is the online updating capability of law and regulations through the internet.

• Journal of Korea Water Resources Association
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• v.39 no.1 s.162
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• pp.59-68
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• 2006

To assess the water resources sustainability, many indicators and methodologies have been suggested by international organizations and developed in other countries. However, in the previous studies, some of indicators were unsuitable for assessing the sustainability of water use and management in Korea. Thus, in this study nSl(Water Resources Sustainability Index), a multi-variable index, was created by consideration of environmental, social, and economical criteria. Relative weights for components, indicators and sub-indexes, were determined by employing the Analytic Hierarchy Process. In order to extract the indicators related with water resources sustainability, the data related with water resources and indicators suggested in various field were compared and thoroughly reviewed. These indicators were classified into four groups; Economic Efficiency Index, Social Equity Index, Environmental Conservation Index, and Maintenance Capability Index. The weight of each component were decided by the survey of 127 specialists in water resources and sustainability. The result of survey represented that efficiency and equity of water use and water quality for river restoration are major issues in enhancing the water resources sustainability In addition, it was found that investment and public participation should be considered for sustainable water use.

• Journal of Korea Society of Industrial Information Systems
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• v.4 no.1
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• pp.34-51
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• 1999

The effective use of IT(information technology) will increasingly become one of the key determinants for successful informationalization in govermental organization And the ability of the public officials in using IT or operating information system is essential to the effective use of IT. This study focuses on constructing a theoretical base of developing the education and training system for enhancing the IT ability of the public officials. In order to achieve this research goal, first this study suggests four categories of IT education and training for (1) the basic capability of IT use (2) the skills of operating information system (3) the management competence of performing strategic use of IT, (4) the expert skills for specific IT, and then derives concrete items for each category. With respect to these items, we empirically investigate the degree of necessity and the effective way of education and training according to tasks, positions and ability of the public officials. The data analyses are based on questionnaires responded by 300 public officials who attend the education and training programs held by the Training Institute of Ministry of Information and Communication. The results of this study can provide the theoretical basis for constructing the IT education and training system which is applicable to most of Korean organizations. Also they can be used as a practical guideline in developing and promoting specific IT education and training programs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.102-111
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• 2016

This study aims to identify the characteristics of the regional innovation system(RIS) and the determinants of innovation performance of SMEs. Data were collected from a questionnaire survey on 64 SMEs in the Daejeon and Chungcheong regions to uncover the relationship between capabilities, regional innovation capacities and innovation performance. The moderating effects of regional innovation capacities on the relationship between firms' innovation capabilities and performance were also tested. Empirical results revealed that R&D, marketing and entrepreneurial orientation had positive effects. The moderating effect of regional innovation capabilities on the relationship between entrepreneurial orientation (risk taking) and performance was also confirmed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.520-526
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• 2016

This study aims to develop a distress prediction model, in order to evaluate the distress prediction power for first-class hotels and to calculate the average financial ratio in the Seoul area by using the financial ratios of hotels in 2015. The sample data was collected from 19 first-class hotels in Seoul and the financial ratios extracted from 14 of these 19 hotels. The results show firstly that the seven financial ratios, viz. the current ratio, total borrowings and bonds payable to total assets, interest coverage ratio to operating income, operating income to sales, net income to stockholders' equity, ratio of cash flows from operating activities to sales and total assets turnover, enable the top-level corporations to be discriminated from the failed corporations and, secondly, by using these seven financial ratios, a discriminant function which classifies the corporations into top-level and failed ones is estimated by linear multiple discriminant analysis. The accuracy of prediction of this discriminant capability turned out to be 87.9%. The accuracy of the estimates obtained by discriminant analysis indicates that the distress prediction model's distress prediction power is 78.95%. According to the analysis results, hotel management groups which administrate low level corporations need to focus on the classification of these seven financial ratios. Furthermore, hotel corporations have very different financial structures and failure prediction indicators from other industries. In accordance with this finding, for the development of credit evaluation systems for such hotel corporations, there is a need for systems to be developed that reflect hotel corporations' financial features.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.182-188
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• 2016

A decoy is a weapon system that can protect vessels from an enemy's torpedo. Thus, the decoy should be able to operate in the field without any failure. Because the decoy can be inoperable once its sealing is broken and water permeates inside the system, the hermetic sealing capability considering the operational environment is mandatory. To be hermetically sealed, a rubber-type O-ring is generally used in a decoy system. The sealed performance of rubber-type products, however, tends to age and deteriorate with time. Therefore, the O-ring needs to be maintained or changed periodically. This paper proposes a method to estimate the proper maintenance period using the hardness and elongation percentage, which represents the performance of the O-ring product and test data from Accelerated Life Test (ALT) of the product. The O-ring used in this paper is a NBR type, and the temperature was chosen to be the main accelerating factor as referenced in many studies. The criteria for the failure of the O-ring was set for the product to be 50% degraded compared to the initial performance. In addition, the Korean standard KS M 6518 was adopted and referenced for the preparation of test samples and the calculation of estimates. The O-ring's predicted life was simulated by analyzing the test results from a computer program, and the optimized maintenance period for the product was determined.

• Experimental and Molecular Medicine
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• v.50 no.12
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• pp.12.1-12.14
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• 2018

Osteoporosis develops with high prevalence in both postmenopausal women and hypogonadal men. Osteoporosis results in significant morbidity, but no cure has been established. Mesenchymal stem cells (MSCs) critically contribute to bone homeostasis and possess potent immunomodulatory/anti-inflammatory capability. Here, we investigated the therapeutic efficacy of using an infusion of MSCs to treat sex hormone-deficient bone loss and its underlying mechanisms. In particular, we compared the impacts of MSC cytotherapy in the two genders with the aim of examining potential gender differences. Using the gonadectomy (GNX) model, we confirmed that the osteoporotic phenotypes were substantially consistent between female and male mice. Importantly, systemic MSC transplantation (MSCT) not only rescued trabecular bone loss in GNX mice but also restored cortical bone mass and bone quality. Unexpectedly, no differences were detected between the genders. Furthermore, MSCT demonstrated an equal efficiency in rectifying the bone remodeling balance in both genders of GNX animals, as proven by the comparable recovery of bone formation and parallel normalization of bone resorption. Mechanistically, using green fluorescent protein (GFP)-based cell-tracing, we demonstrated rapid engraftment but poor inhabitation of donor MSCs in the GNX recipient bone marrow of each gender. Alternatively, MSCT uniformly reduced the $CD3^+T$-cell population and suppressed the serum levels of inflammatory cytokines in reversing female and male GNX osteoporosis, which was attributed to the ability of the MSC to induce T-cell apoptosis. Immunosuppression in the microenvironment eventually led to functional recovery of endogenous MSCs, which resulted in restored osteogenesis and normalized behavior to modulate osteoclastogenesis. Collectively, these data revealed recipient sexually monomorphic responses to MSC therapy in gonadal steroid deficiency-induced osteoporosis via immunosuppression/anti-inflammation and resident stem cell recovery.