• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.12
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• pp.1275-1281
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• 2001

Aqueous polymer solutions are known to have small pressure reduction. Paraffin slurries are known to have high thermal capacity. Paraffin particles are mixed into an aqueous polymer solution to make a new heat transfer fluid having high thermal capacity but low pressure reduction. The heat transfer characteristics of the new slurry was tested in a circular tube having a constant heat transfer boundary condition. The new slurry was found to have high Nusselt numbers as well as high thermal capacity and low pressure reduction in the laminar flow. The trends of the Nusselt numbers along the heating test section were studied for various heating conditions.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.69-72
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• 2002

본 논문에서 화자공간모델 evolution에 기반한 continuous density hidden Markov model (CDHMM)의 online 적응에 대한 새로운 기법을 제안한다. 학습화자의 a priori knowledge을 나타내는 화자공간모델은 factor analysis (FA) 또는 probabilistic principal component analysis (PPCA)와 같은 은닉변수모델(latent variable model)에 의해 효과적으로 나타내어진다. 은닉 변수모델은 화자공간모델뿐아니라 CDHMM 파라메터의 ajoint prior분포를 표시함으로, maximum a posteriori(MAP)적응기법에 직접 적용되어진다. 화자공간모델의 hyperparameters와 CDHMM파라메터를 동시에 순차적으로 적응하기 위해 quasi-Bayes (QB)추정 기술에 기반한 online 적응기법을 제안한다. 연속숫자음 인식과 관련된 화자적응 실험을 통해 제안된 기법은 적은 적응데이터에서 좋은 성능을 나타내며, 데이터가 증가함에 따라 성능이 지속적으로 증가함을 보여준다.

• Journal of Korea Multimedia Society
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• v.20 no.1
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• pp.66-73
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• 2017

Due to the recent rapid changes in society and wide spread of information devices, diverse digital information is utilized in a variety of economic and social analysis. Information related to the crime statistics by type of crime has been used as a major factor in crime. However, statistical analysis using only the structured data has the difficulty in the investigation by providing limited information to investigators and users. In this paper, structured data and unstructured data are analyzed by applying Korean Natural Language Processing (Ko-NLP) and the Latent Semantic Analysis (LSA) technique. It will provide a crime profile optimum system that can be applied to the crime profiling system or statistical analysis.

• International journal of advanced smart convergence
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• v.8 no.2
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• pp.39-46
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• 2019

Human mobility estimation plays a key factor in a lot of promising applications including location-based recommendation systems, urban planning, and disease outbreak control. We study the human mobility estimation problem in the case where recent locations of a person-of-interest are unknown. Since matrix decomposition is used to perform latent semantic analysis of multi-dimensional data, we propose a human location estimation algorithm based on matrix factorization to reconstruct the human movement patterns through the use of information of persons with correlated movements. Specifically, the optimization problem which minimizes the difference between the reconstructed and actual movement data is first formulated. Then, the gradient descent algorithm is applied to adjust parameters which contribute to reconstructed mobility data. The experiment results show that the proposed framework can be used for the prediction of human location and achieves higher predictive accuracy than a baseline model.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.27 no.6
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• pp.513-522
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• 1998

우리나라의 여름 기후는 고온 다습한 특징을 갖고 있다. 고온 다습한 지역에서는 습도가 쾌적성을 결정하는데 중요한 요소가 되기 때문에, 습도가 높으면 온도가 그다지 높지 않더라도 쉽게 무더위를 느낀다. 이러한 계절적 특성을 없애 쾌적한 생활을 영위하기 위하여 생활의 질적 향상과 더불어 공조장치의 수요가 매년 두드러지게 증가하고 있다. 특히, 실내의 경우에는 공조장치 중 대표적인 에어컨(air conditioner)으로 냉방을 행함으로써 고온 다습한 여름철의 거주공간을 개선하고 있다. 그러나 고온 다습한 환경하에서의 과다한 에어컨 사용은 인체의 온열 환경적 측면에서 오히려 불리하다. 왜냐 하면, 에어컨에서는 여름철에 잠열(latent heat)을 고려해야 함에도 불구하고 단지 현열비(sensible heat factor)로 취출온도를 결정하고 있기 때문이다. 그 결과, 실내가 과다하게 냉각되어 재실자에게 불쾌감은 물론, 심지어 냉방병도 초래할 수가 있다.

• Asia pacific journal of information systems
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• v.29 no.2
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• pp.181-202
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• 2019

The purpose of this study is to explore the effect of different types of simultaneous presentation (i.e., reviewer information, textual and visual content, and similarity between textual-visual contents) on review usefulness and review enjoyment in online restaurant reviews (ORRs), as they are interrelated yet have rarely been examined together in previous research. By using Latent Dirichlet Allocation (LDA) topic modeling and state-of-the-art machine learning (ML) methodologies, we found that review readability in textual content and salient objects in images in visual content have a significant impact on both review usefulness and review enjoyment. Moreover, similarity between textual-visual contents was found to be a major factor in determining review usefulness but not review enjoyment. As for reviewer information, reputation, expertise, and location of residence, these were found to be significantly related to review enjoyment. This study contributes to the body of knowledge on ORRs and provides valuable implications for general users and managers in the hospitality and tourism industries.

• Journal of Science Education
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• v.41 no.1
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• pp.16-35
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• 2017

This study attempted to investigate the relationship among engineering students' creativity, engineering education accreditation, gender, and academic year. To be specific, fist, we examined the validity and reliability of the instrument for measuring engineering students' creativity by conducting Rasch analysis. Second, we compared level of creativity in terms of gender, academic year, and engineering education accreditation by using three-way ANOVA. Third, correlations among four constructs of creativity were examined. Fourth, latent classes with respect to creativity within the participants were identified using polytomous latent class analysis (poLCA). Data were collected from 2098 engineering students by using instrument for measuring four different constructs (creative cognition, creative tendency, collaboration, environment). By using Rasch analysis, validity and reliability of instrument for measuring creativity were confirmed. And the results of three-way ANOVA showed that there were significant difference in creativity in terms of gender. Female students showed the low level of creativity compared with male students. Also there were significant difference in creativity except creative cognition factor in terms of academic year. But there were no significant difference in creativity between students who participated engineering education accreditation program and the others. All constructs of creativity were significantly correlated with each others. Lastly, poLCA results showed that there were three distinct subgroups within engineering students in terms of the level of creativity. In the subgroup with low creativity, there were more female and first year students. Based on these findings, we discussed education for engineering students' creativity.

• Journal of Adhesion and Interface
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• v.5 no.1
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• pp.3-11
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• 2004

In this work, the cure behaviors of the DGEBA/PMR-15 blends initiated by N-benzylpyrazinium hexafluoroantimonate (BPH) as a cationic latent catalyst were performed in DSC and DMA analyses. And, the thermal stabilities were carried out by TGA analysis and their mechanical interfacial properties of blends were measured in the context of critical stress intensity factor ($K_{IC}$). As a result, the curing activation energy ($E_a$) determined from Ozawa's equation in DSC and the relaxation activation energy ($E_r$) from DMA were increased with increasing PMA-15 content. Also, the thermal stabilities obtained from the integral procedural decomposition temperature (IPDT) and the glass transition temperature ($T_g$) were highly improved with increasing the PMR-15 content, which were probably due to the high heat resistance. And, the $K_{IC}$ showed a similar behavior with $E_a$, which was attributed to the improving of the interfacial adhesion or hydrogen bondings between intermolecular chains.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.11 no.2
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• pp.107-114
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• 2017

Results of the analysis have revealed that the students were basically divided into three groups depending on goodness-of-fit index and latent class division factor. Type 1 was regarded as a low dependence group (50.1%) with all low indexes while Type 2 was classified as a high dependence group (10.7%) with all high indexes. As for Type 3, it was titled intermediate dependence group (39.2%) for the indexes showed a low-to-moderate movement. A multinomial logistic regression analysis was carried out to forecast smart phone dependence characteristics and as a consequence, when the high dependence group was compared to the intermediate dependence group, as self-esteem and peer attachment increased and deceased respectively, a chance of one being classified into the intermediate dependence group rose. In an investigation to compare the high dependence group with the low dependence group, it was confirmed that the greater the self-esteem, the shorter the peer socializing time, the lower the neglect degree and the lower the peer attachment, a chance for one belonging to the low dependence group increased. This study also offered implications, limits and directions in follow-up research.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.7
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• pp.267-278
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• 2017

The aim of this paper was to develop a scale for measuring gender identity among sports participants (114 male, 193 female). Gender similarities and latent mean analysis was used to validate the gender identity measurement method. Data processing was carried out by way of frequency analysis, exploratory and confirmatory factor analysis, reliability, correlation, normal distribution of questions, and latent mean analysis using SPSS 18.0 and AMOS 18.0. The results of this study were as follows: First, the equivalence had revealed the configurable, metric, and scalar invariance of the scale that can be used in multi-groups in the same way. Second, women had a more open inclination than men when it came to participating in sports activities (p<.001). Third, women participating in sports activities tended to be more conservative than men (p<.001). Fourth, women who participated in sports activities showed a higher subjective tendency than men (p<.001). Fifth, there was no statistical difference in the outward tendency when participating in sports activities (p<.05). The results of this study suggest that gender identity among sports participants is not influenced by the changing times and the advancement of women in society.