• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.7
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• pp.417-427
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• 2016

This paper is the first investigation of the steady flow characteristics of an SI engine with a semi-wedge combustion chamber as a function of the port shape. For this purpose, the planar velocity profiles were measured at the 1.75B position by particle image velocimetry. The flow patterns were examined with both a straight and a helical port. Two swirls were observed up to 4 mm valve lift with the straight port and up to 2 mm with the helical one; however, only one swirl was present after these lifts. The flow characteristics changed suddenly between 4 and 5 mm lift in the straight port; on the other hand, the change with lift was gradual with the helical port - the transition points between flow regimes were different with the port shapes. In addition, the centers of the swirls were relatively far from the cylinder center so that the effect of eccentricity may not be negligible at 1.75B, regardless the shape. The eccentricity values with the straight port were especially high - over 0.5 for all lifts. Finally, real velocities were found to be much lower than those predicted by the assumption of ISM evaluation, with the profiles differing qualitatively as well.

• Korean Journal of Materials Research
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• v.18 no.4
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• pp.222-227
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• 2008

In this study, $BaTiO_3$ thin films were grown by RF-magnetron sputtering, and the effects of a post-annealing process on the structural characteristics of the $BaTiO_3$ thin films were investigated. For the crystallization of the grown thin films, post-annealing was carried out in air at an annealing temperature that varied from $500-1000^{\circ}C$. XRD results showed that the highest crystal quality was obtained from the samples annealed at $600-700^{\circ}C$. From the SEM analysis, no crystal grains were observed after annealing at temperatures ranging from 500 to $600^{\circ}C$; and 80 nm grains were obtained at $700^{\circ}C$. The surface roughness of the $BaTiO_3$ thin films from AFM measurements and the crystal quality from Raman analysis also showed that the optimum annealing temperature was $700^{\circ}C$. XPS results demonstrated that the binding energy of each element of the thin-film-type $BaTiO_3$ in this study shifted with the annealing temperature. Additionally, a Ti-rich phenomenon was observed for samples annealed at $1000^{\circ}C$. Depth-profiling analysis through a GDS (glow discharge spectrometer) showed that a stoichiometric composition could be obtained when the annealing temperature was in the range of 500 to $700^{\circ}C$. All of the results obtained in this study clearly demonstrate that an annealing temperature of $700^{\circ}C$ results in optimal structural properties of $BaTiO_3$ thin films in terms of their crystal quality, surface roughness, and composition.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.2
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• pp.97-107
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• 2017

This study is the second investigation on the steady flow characteristics of an SI engine with a semi-edge combustion chamber as a function of the port shape with varying evaluation positions. For this purpose, the planar velocity profiles were measured from 1.75B, 1.75 times of bore position apart from the bottom of head, to 6.00B positions using particle - image velocimetry. The flow patterns were examined with both a straight and a helical port. The velocity profiles, streamlines, and centers of swirl were almost the same at the same valve lift regardless of the measuring position, which is quite different from the case of the pent-roof combustion chamber. All the eccentricity values of the straight port were out of distortion criterion 0.15 through the lifts and the position. However, the values of the helical port exceeded the distortion criterion by up to 4 mm lift, but decreased rapidly above the 3.00B position and the 5 mm lift. There always existed a relative offset effect in the evaluation of the swirl coefficient using the PIV method due to the difference of the ideal impulse swirl meter velocity profile assumption, except for the cylinder-center-base estimation that was below 4 mm of the straight port. Finally, it was concluded that taking the center as an evaluation basis and the assumption about the axial velocity profile did not have any qualitative effect on swirl evaluation, but affected the value owing to the detailed profile.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.311-316
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• 2017

The network analysis method has emerged as a new methodology for various disciplines, due to its ability to provide a representative knowledge network of references, co-authors and keywords. Bulletproof technology is an interdisciplinary field involving various disciplines, such as material mechanics, structural mechanics, and ballistics, so it is essential to keep up with the recent trends in technological research. In this research, the recent R&D trends in the field of bulletproof materials were analyzed using keyword based network analysis. From the results, the core keywords were identified as 'Composite', 'Model' and 'Head' using the scholar search engine, google scholar. The centrality analysis for the core keywords showed that bulletproof technology has developed in 3 different areas, viz. material, structure and effects. To the best of our knowledge, this is the first application of (network analysis?) to bulletproof technology. Moreover, we are also convinced that the results of this study will be useful for defense technology planning and determining the direction of R&D in the field of bulletproof technology.

• 재활복지
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• v.21 no.1
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• pp.27-46
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• 2017

The purpose of this study is to develop tool for the assessment of employment preparedness for people with visual impairments. First, we developed a draft assessment factors. Expert opinion survey, delphi survey, pilot test were conducted to modify contents of the factors. Actual assessments were carried out to test the reliability and validity of the developed tool targeting job seeker with visual disabilities. The total number of valid samples are 253. Principal component analysis, confirmatory factors analysis, and correlation analysis were used for the validity test. Chronbach' alpha analysis was used for the reliability test. As a result of the reliability analysis, the reliability coefficient showed good level of 0.88-0.92. As a result of the factor analysis, it was confirmed that the composition concept of 9 factors were well reflected. The correlation coefficient between employment preparedness tool and job screening tool was 0.501, Which was statistically significant. Therefore, it was evaluated as having a concurrent validity. Finally, it was confirmed that the assessment of employment preparedness for people with visual impairments was valid as assessment tool.

• The Journal of the Convergence on Culture Technology
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• v.7 no.4
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• pp.75-83
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• 2021

This study will analyze the meaning of the signifiant, which occupies an absolute position in Lacanian psychoanalysis, and will prove the slip of meaning and signification that are accompanied together at the same time when the signifiant was utter through the subject. By directly citing the part where Lacan explained signification in his seminars and Écrits, I would like to examine how signifiant is carried out in everyday conversation. In addition, the dialogue that takes place in our discourse has the purposefulness and groundless purposelessness of the signifiant. Understanding this purpose is the core part that Lacanian psychoanalysis aims to pursue, and it discovers the cracks of the hidden meaning in the relationship between the signifiant and the signifiant connected to the next, presenting that the signifiant which arouses unrelenting fantasy of the subject is the practical ruler of body and mind. This thesis is aimed to present the above points mentioned above, and as an alternative to overcome the limitations of the signifiant, the ruler in discourse, this study would like to suggest the autonomy as a subject resisting against "Where it was, I must come into being," pursued by Lacan psychoanalysis.

• Journal of the Korean Society for information Management
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• v.39 no.1
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• pp.309-330
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• 2022

Intellectual structure analysis, which quantitatively identifies the structure, characteristics, and sub-domains of fields, has rapidly increased in recent years. Analysis techniques traditionally used to conduct intellectual structure analysis research include bibliographic coupling analysis, co-citation analysis, co-occurrence analysis, and author bibliographic coupling analysis. This study proposes a novel intellectual structure analysis method, Keyword Bibliographic Coupling Analysis (KBCA). The Keyword Bibliographic Coupling Analysis (KBCA) is a variation of the author bibliographic coupling analysis, which targets keywords instead of authors. It calculates the number of references shared by two keywords to the degree of coupling between the two keywords. A set of 1,366 articles in the field of 'Open Data' searched in the Web of Science were collected using the proposed KBCA technique. A total of 63 keywords that appeared more than 7 times, extracted from 1,366 article sets, were selected as core keywords in the open data field. The intellectual structure presented by the KBCA technique with 63 key keywords identified the main areas of open government and open science and 10 sub-areas. On the other hand, the intellectual structure network of co-occurrence word analysis was found to be insufficient in the overall structure and detailed domain structure. This result can be considered because the KBCA sufficiently measures the relationship between keywords using the degree of bibliographic coupling.

• Journal of the Korean earth science society
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• v.44 no.3
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• pp.236-252
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• 2023

Both Earth science II and Korean geography textbooks emphasize the importance of content related to 'geology of the Korean Peninsula'. This study aimed to analyze the differences in the content related to the 'geology of the Korean Peninsula' presented in the textbooks, and to find out whether these differences are consistent with the latest scientific knowledge in any inconsistencies are found. For this purpose, seven textbooks (four Earth science II and three Korean geography) published under the 2015 revised curriculum were selected as the subject of analysis, and the difference in the description of the tectonic provinces of the Korean Peninsula, geologic time scale, and explanatory texts of geological characteristics between Earth science II and Korean geography textbooks were compared. As a result of the analysis, there are some cases of inconsistencies between Earth science II and Korean geography textbooks in terms of terminologies, names, and distribution ranges related to the tectonic provinces of the Korean Peninsula. The Korean geography textbooks had inconsistencies in the geochronologic data of the rocks as they cited outdated data. In addition, inconsistencies were found in the explanatory texts describing the 'distribution of rocks on the Korean Peninsula', 'characteristics of the Pyeongan Supergroup', and 'great hiatus of the Paleozoic Era'. Both Earth science and Geography have many concepts in common, therefore, effort is needed to minimize the differences in content. It is important to select the content appropriately which should reflect the latest scientific knowledge and presents the concepts consistently.

• Journal of Korean Library and Information Science Society
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• v.54 no.3
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• pp.321-346
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• 2023

A data paper describing research data helps credit researchers producing the data while helping other researchers verify previous research and start new research by reusing the data. Publishing a data paper and depositing data to a public data repository are increasing with these benefits. A domestic academic society that plans to publish data papers faces challenges, including timely acquiring tremendous knowledge concerning data paper structures and templates, peer review policy and process, and trustworthy data repositories, as a data paper has different characteristics, unlike a research paper. However, the need for more research and information concerning the critical elements of data paper and the peer-review process makes it difficult to operate for data paper review and publication. To address these issues, we propose essential concepts of the data paper and the data paper peer-review, including the process model of the peer-review with in-depth analysis of five data journals' data paper templates, articles, and other guides worldwide. Academic societies intending to publish or add data papers as a new type of paper may establish policies and define a peer-review process by adopting the proposed conceptual models, effectively streamlining the preparation of data paper publication.

• Journal of the Korean Society for information Management
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• v.41 no.2
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• pp.295-316
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• 2024

Analyzing research trends is essential for the sustainable development of a discipline and is important for understanding the value of prior research and laying the groundwork for subsequent research. This study aims to draw implications for the future direction of convergence research on the disclosure of information from various disciplines by comparing and analyzing the trends in disclosure of information research in Korea. For this purpose, we analyzed the publication frequency of information disclosure papers listed in the Korea Citation Index (KCI) from 2002 to 2023 and the publication trend by discipline as a time series. In addition, we compared the keyword relationships and specialized research topics of each discipline by applying network analysis and LDA topic modeling techniques to the names and keywords of papers in law, public administration, and library and information science. As a result of the analysis, the law focuses on legal regulations and policy improvement, public administration focuses on changing social needs and administrative operation methods, and LIS focuses on practical approaches to record management and disclosure of information. Based on this, future research directions include combining policy research in law with social change research in public administration and developing realistic policies and operational guidelines from the practical perspective of LIS. Such convergent research will enable the systematic and efficient implementation of disclosure of information systems, contributing to the guarantee of the public's right to know and the enhancement of state transparency.