• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.48.4-49
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• 2020

We reconstruct the expansion history of the universe using type Ia supernovae (SN Ia) in a manner independent of any cosmological model assumptions. To do so, we implement a nonparametric iterative smoothing method on the Joint Light-curve Analysis (JLA) data while exploring the SN Ia light-curve hyperparameter space by Markov Chain Monte Carlo (MCMC) sampling. We test to see how the posteriors of these hyperparameters depend on cosmology, whether using different dark energy models or reconstructions shift these posteriors. Our constraints on the SN Ia light-curve hyperparameters from our model-independent analysis are very consistent with the constraints from using different parameterizations of the equation of state of dark energy, namely the flat ΛCDM cosmology, the Chevallier-Polarski-Linder model, and the Phenomenologically Emergent Dark Energy (PEDE) model. This implies that the distance moduli constructed from the JLA data are mostly independent of the cosmological models. We also studied that the possibility the light-curve parameters evolve with redshift and our results show consistency with no evolution. The reconstructed expansion history of the universe and dark energy properties also seem to be in good agreement with the expectations of the standard ΛCDM model. However, our results also indicate that the data still allow for considerable flexibility in the expansion history of the universe. This work is published in ApJ.

• KIISE Transactions on Computing Practices
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• v.22 no.5
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• pp.235-239
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• 2016

'Commit-bug link', the link between commit history and bug reports, is used for software maintenance and defect prediction in bug tracking systems. Previous studies have shown that the links are automatically detected based on text similarity, time interval, and keyword. Existing approaches depend on the quality of commit history and could thus miss several links. In this paper, we proposed a technique to link commit and bug report using not only messages of commit history, but also the similarity of files in the commit history coupled with bug reports. The experimental results demonstrated the applicability of the suggested approach.

• Journal for History of Mathematics
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• v.28 no.6
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• pp.349-363
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• 2015

In this paper, we explore about Korean early childhood mathematics education history. Actually, mathematics education history is mathematics education curriculum's history. Korean education curriculum has been influenced by the US and European prominent educators: Montessori, Piaget, Bruno, and Dewey, etc. We investigate how those philosophy and thoughts were adopted in Korean early childhood mathematics education curriculums from 1st to 2015 amended curriculum. Also, we can see that NCTM's content standards and Korean Nuri curriculum are the same in the basic concepts: number and operations, space and shapes, measurement, understanding of patterns and data collection.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.12
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• pp.1223-1229
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• 2001

Though conventional calorimetry methods such as differential scanning calorimetry (DSC) and differential thermal analysis (DTA) are used generally in measuring heat of fusion, T-history method has the advantages of a simple experimental apparatus and no requirements of sampling process, which is particularly useful for measuring thermal properties of inhomogeneous phase change materials (PCMs) in sealed tubes. However, random criteria (a degree of supercooling) used in selecting the range of latent heat release and neglecting sensible heat during the phase change process can cause significant errors in determining the heat of fusion. In the present study, it was shown that a 40% discrepancy exists between the original T-history and the present methods when analyzing the same experimental data. As a result, a reasonable modification to the original T-history method is proposed.

• Journal of the Korean Society for Library and Information Science
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• v.22
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• pp.331-360
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• 1992

This research presents author co-citation analysis of the subject area in the humanities - Korean history. Three approaches to multivariate analyses were used to display the inter-author relationships in the similarity matrix. Data on co-citation of sixty seven authors for the period of 1980­1989 were extracted from the database constructed by author. The author's name, here refers to a body of writings by a person, is the unit of analysis. The data were subjected to non-metric multidimensional scaling program create two-dimensional map of authors. Authors with similarity are clustered using hierarchical agglomerative procedure and it is found that five clusters in Korean history represent primarily research specializations. Author map of Korean history reveals the first dimension corresponding to subject orientation of authors and the second dimension corresponds to research method or research style. In factor analysis, each factor reflects research specialty made up of authors, and factor locadings demonstrate the breadth or concentration of sixty seven authors' scholarly contributions on Korean history. It is demonstrated that the· specific methodology employed by this research, author co-citation analysis, is useful to represent the intellectual structure of Korean history.

• The KIPS Transactions:PartD
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• v.17D no.2
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• pp.87-102
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• 2010

A vast amount of traffic data is produced every day from detection devices but this data includes a considerable amount of errors and missing values. Moreover, this information is periodically deleted before it could be used as important analysis information. Therefore, this paper discusses the implementation of an integrated traffic history database system that continuously stores the traffic data as a multidimensional model and increases the validity and completeness of the data via a flow of processing steps, and provides a what-if analysis function. The implemented system provides various techniques to correct errors and missing data patterns, and a what-if analysis function that enables the analysis of results under various conditions by allowing the flexible definition of various process related environment variables and combinations of the processing flows. Such what-if analysis functions dramatically increase the usability of traffic data but are not provided by other traffic data systems. Experimantal results for cleaning the traffic history data showed that it provides superior performance in terms of validity and completeness.

• The KIPS Transactions:PartA
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• v.14A no.1 s.105
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• pp.55-62
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• 2007

Uptime of embedded processors for mobile devices are dependent on battery consumption. Especially the large portion of power consumption is known to be due to cache management in embedded processors. This paper proposes an energy efficient data cache structure for high performance embedded processors. High performance prefetching data cache issues prefetching instructions before issuing demand-fetch instructions based on reference predictions. These prefetching instruction bring reduction on memory delay by improving cache hit ratio, but on the other hand those increase energy consumption in proportion to the number of prefetching instructions. In this paper, we adopt tag history table on prefetching data cache for reducing energy consumption by minimizing parallel tag comparison. Experimental results show the proposed data cache improves performance on energy consumption as well as memory delay.

• Journal of Korean Medical classics
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• v.33 no.4
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• pp.67-81
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• 2020

Objectives : This research aims to suggest a automatic data extract method for herbal formula combinations from medical classics' texts. Methods : This research was carried out by using Access of Microsoft Office 365 in Windows 10 of Microsoft. The subject text for extraction was 『Euijongsonik』. Using data sets of herb and dosage terminology, herbal medicinals and their dosages were extracted. Afterwards, using the position value of the character string, the formula combinations were automatically extracted. Results :The PC environment of this research was Intel Core i7-1065G7 CPU 1.30GHz, with 8GB of RAM and a Windows 10 64bit operation system. Out of 6,115 verses, 19,277 herb-dosage combinations were extracted. Conclusions : In this research, it was demonstrated that in the case of classical texts that are available as data, knowledge on herbal medicine could be extracted without human or material resources. This suggests an applicability of classical text knowledge to clinical practice.

• Journal of Preventive Medicine and Public Health
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• v.50 no.5
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• pp.294-302
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• 2017

Objectives: The objectives of this study were to investigate the agreement between medical history questionnaire data and claims data and to identify the factors that were associated with discrepancies between these data types. Methods: Data from self-reported questionnaires that assessed an individual's history of hypertension, diabetes mellitus, dyslipidemia, stroke, heart disease, and pulmonary tuberculosis were collected from a general health screening database for 2014. Data for these diseases were collected from a healthcare utilization claims database between 2009 and 2014. Overall agreement, sensitivity, specificity, and kappa values were calculated. Multiple logistic regression analysis was performed to identify factors associated with discrepancies and was adjusted for age, gender, insurance type, insurance contribution, residential area, and comorbidities. Results: Agreement was highest between questionnaire data and claims data based on primary codes up to 1 year before the completion of self-reported questionnaires and was lowest for claims data based on primary and secondary codes up to 5 years before the completion of self-reported questionnaires. When comparing data based on primary codes up to 1 year before the completion of selfreported questionnaires, the overall agreement, sensitivity, specificity, and kappa values ranged from 93.2 to 98.8%, 26.2 to 84.3%, 95.7 to 99.6%, and 0.09 to 0.78, respectively. Agreement was excellent for hypertension and diabetes, fair to good for stroke and heart disease, and poor for pulmonary tuberculosis and dyslipidemia. Women, younger individuals, and employed individuals were most likely to under-report disease. Conclusions: Detailed patient characteristics that had an impact on information bias were identified through the differing levels of agreement.

• Journal of Physiology & Pathology in Korean Medicine
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• v.25 no.4
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• pp.734-742
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• 2011

The purpose of this study was to investigate the distribution and correlation of stroke risk factor according to age with stroke patients. This study was based on clinical data registered in Daejeon Oriental Medical Hospital from November 2006 to December 2010. Study subjects consisted of 779 patients with stroke within 1 month and they were classified according to age and existence of past history such as hypertension, diabetes mellitus, ischemic heart diseaseand stroke family history. Stroke family history was distributed differently according to age unlike past history and in their 50's showed a particularly high rate. There was not statistically significant correlation between stroke family history and past history except for only between stroke family history and diabetes mellitus in the patients in their 80's and more. There was statistically significant correlation between hypertension and diabetes mellitus and especially in the patients in their 60's and 70's. There was statistically significant correlation between hypertension and ischemic heart disease and especially in the patients in their 80's and more. There was statistically significant correlation between diabetes mellitus and ischemic heart disease in the patients in their 60's. There was statistically significant correlation among hypertension, diabetes mellitus and ischemic heart disease, but stroke family history and past history had independence, so management and research for this subject should be required further and further.