• Journal of the Korean Society of Radiology
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• v.13 no.3
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• pp.445-451
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• 2019

The fluorescence intensity and fluorescence lifetime of $Ba_2GdV_3O_{11}$, a vanadate compound based on $Ba^{2+}$ ion, were investigated by adding $Eu^{3+}$ as a rare earth ion which is an alkaline earth metal, which is distributed around active ions and has a large influence on fluorescent properties when used as a host in a phosphor. $Ba_2GdV_3O_{11}:Eu^{3+}$ phosphor was synthesized by solid state method and the crystallinity of the phosphor was confirmed by X - ray diffraction analysis. The fluorescence properties of the $Ba_2GdV_3O_{11}:Eu^{3+}$ phosphor were measured using optical and laser. The energy transfer and diffusion of the $Ba_2GdV_3O_{11}:Eu^{3+}$ phosphor are highly dependent on the concentration of $Eu^{3+}$. When the concentration of $Eu^{3+}$ is low, it shows strong fluorescence to the CT band. However, as the concentration of $Eu^{3+}$ increases, the fluorescence due to 4f - 4f transition is strong. The concentration of $Eu^{3+}$ ion increased and the energy between ions was diffused, and the lifetime of fluorescence decreased. Energy transfer occurs between two $Eu^{3+}$ ions at low $Eu^{3+}$ concentration and energy diffusion occurs at high $Eu^{3+}$ concentration.

• Industry Promotion Research
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• v.4 no.1
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• pp.29-43
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• 2019

This study is to discusses the relevance of social welfare in Freud's psychoanalytic theory. The results of the study are as follows. First, psychoanalytic theory details the client's family history and personal history to help them identify the characteristics of the problem they have today. At this time, social workers actively listen to clients and try to get various information.Second, when used in psychoanalytic techniques, the resistance of the client can be interpreted and analyzed to help the client maintain friendly relationships with the client.Third, psychoanalytic theory can properly apply the client's current state of mind by understanding the potential conflicts or emotions that exist in the client's unconscious mind. Fourth, during the process of intervention, social workers need to deal well with the client's transition response. This process allows social workers to observe the effect of reducing the stimuli that can cause nervousness in clients.In conclusion, all the techniques of interpretation used in psychoanalytic theory are, after all, techniques that help social workers improve clients' insight into their problems and help clients solve their psychological problems themselves. The psychoanalytic theory is widely applied in social welfare.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.910-917
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• 2018

This paper describes the developments to improve the feeling and safety of the remote control system of unmanned vehicles. Generally, in the case of the remote control systems, a joystick-type device or a simple steering-wheel are used. There are many cases, in which there are operations without considering the feedback to users and driving feel. Recently, as the application area of the unmanned vehicles has been extended, the problems caused by not considering the feedback are emphasized. Therefore, the need for a force feedback-haptic control arises to solve these problems. In this study, the force feedback-haptic control algorithm considering the vehicle parameters is proposed. The vehicle parameters include first the state variables of dynamics, such as the body side-slip angle (${\beta}$) and yawrate (${\gamma}$), and second, the parameters representing the driving situations. Force feedback-haptic control technology consists of the algorithms for general and specific situations, and considers the situation transition process. To verify the algorithms, a simulator was constructed using the vehicle dynamics simulation tool with CAN communication environment. Using the simulator, the feasibility of the algorithms was verified in various scenarios.

• Korean Journal of Materials Research
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• v.31 no.10
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• pp.562-568
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• 2021

(Bi_1/2Na_1/2)TiO₃ (BNT)-based ceramics are considered promising candidates for actuator application owing to their excellent electromechanical strain properties However, to obtain large strain properties, there remain several issues such as thermal stability and high operating fields. Therefore, this study investigates a reduction of operating field in (0.98-x)Bi_1/2Na_1/2TiO₃-0.02 BiAlO₃-xSrTiO₃ (BNT-2BA-100xST, x = 0.20, 0.21, 0.22, 0.23, and 0.24) via analyses of the microstructure, crystal structure, dielectric, polarization, ferroelectric and electromechanical strain properties. The average grain size of BNT-${\underline{2}}$BA-100xST ceramics decreases with increasing ST content. Results of polarization and electromechanical strain properties indicate that a ferroelectric to relaxor state transition is induced by ST modification. As a consequence, a large electromechanical strain of 592 pm/V is obtained at a relatively low electric field of 4 kV/mm in 22 mol% ST-modified BNT-2BA ceramics. We believe that the materials synthesized in this study are promising candidates for actuator applications.

• The Mathematical Education
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• v.61 no.4
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• pp.521-537
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• 2022

The unprecedented COVID-19 pandemic has disrupted, interrupted, and changed the way we normally prepare our teacher candidates in teacher preparation programs. In this paper, we, two mathematics teacher educators (MTEs), reflect our own experiences in appropriating, transforming, reconstructing, and modifying our pedagogies of teacher education in making a transition from face-to-face to online environment during the COVID-19 pandemic. Using a collaborative self-study, we discussed issues, challenges, changes, opportunities, and innovations of teaching an elementary mathematics methods course in the online environment. Using a constant comparison method, we explored the following three themes: (1) using virtual manipulatives; (2) creating collaborative, interactive, and shared learning experiences for preservice teachers; and (3) making preservice teachers engaged in student thinking. These findings indicated that online teaching requires transformative knowledge for teacher educators. Transferring face-to-face to online is not a simple matter of putting the existing content to online; it should focus on pedagogical improvement in teaching mathematics rather than technology's sake or how it can be repurposed in a new online environment in a way that students' learning is optimized. The findings of this study provide implications for unpacking MTEs' technological pedagogical content knowledge (TPACK), creating collaborative learning experiences for preservice teachers, and designing a collaborative self-study between MTEs engaged in the community of professional learning.

• 동북아역사논총
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• no.60
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• pp.196-227
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• 2018

The issues of this study are as follows. First, I will examine the overall situation and transition trends of Tibetan research in Taiwan since the modern period, and examine the development and trends of Tibetan history research in Taiwan. Secondly, in order to satisfy the above, we will analyze trends of Taiwan's major Tibetan research institutes and scholars, and trace their trends and their trajectories. Third, the trend of Tibetan research in Taiwan may be a useful indicator for us to analyze research methods and trends of Taiwanese scholars. If there is a flow of features and transitions, the text will explore the reason. Fourth, one of the implications of this study is that it can trigger an understanding of locality in the structure of the central region, the Han Chinese minority, and the possession and distribution of academic reasoning. In other words, it should be noted that even though the same Tibetan research is conducted, China is in the position of the vested right to distribute 226 | 동북아역사논총 60호the central or ownership, while Taiwan has historical and territorial characteristics that deviate from such a gaze and attitude. Taiwan may be sensitive to the vertical concept understood as a change in the relationship between the state and the center, or whether it is applicable to Tibetan research. If there is such an academic climate, I would like to consider suggestions for us. This may provide a direction to view the academic issues of a few scholars, or even the domestic academic world as an independent object of more specific academic research.

• The Journal of Korean Philosophical History
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• no.35
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• pp.165-188
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• 2012

The purpose of this study is to examine the historical consciousness and view of the three religions (Buddhism, Taoism, and Confucianism) of Won Cheon Seok who lived a period of historical transition from the end of the Goryeo Dynasty to the early Joseon Dynasty. Actively speaking for the public in his time and having the same attitude as the Neo-Confucian scholars in the end of Goryeo Dynasty, he kept criticizing the abuse of the power by powerful families who made the people fall into a state of distress and misery. He believed the dispatch of troops to conquer the Yodong region as a great opportunity to boost the valiant spirit of his country; however, the reality was quite opposite to his expectation as Lee Seong Gye had withdrawn the army troops at the Wihwado causing a great risk to his country. He took a very hard line stance against what Lee Seong Gye did. Although he was a Confucian scholar, he did not ignore Buddhism and Taoism and understood that after all the three religions were based on the same principle. His deep understanding of Buddhism and Taoism as well as Confucianism helped him to make sense of Confucianism even further. He was able to sublimate the worldly anguish coming from the Confucian thinking system by indulging himself deeply into the world view of Buddhism and Taoism. In the end, his view on the three religions was based on the idea that they taught the same principle. His view of the three religions with transactional features has a huge implication for the contemporary society in which various values and multiple cultures coexist and have more common grounds.

• Journal of the Korean Society of Radiology
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• v.15 no.3
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• pp.391-399
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• 2021

Eu²⁺ doped polyphosphate NaSr(PO₃)₃ blue-emitting phosphors were synthesized by the conventional solid state method in a reductive atmosphere. The phase formation of NaSr(PO₃)₃ phosphors were characterized by using the X-ray powder diffraction (XRD) measurement. The photoluminescence emission and excitation spectra of the NaSr(PO₃)₃:Eu²⁺ phosphor, and decay curves were measured. Under the near-UV excitation, the phosphor exhibits a band emission around 420 nm assigned to the 4f⁶5d→f7(8S^7/2) transition of Eu²⁺. The temperature dependent emission spectra and decay curves were measured to elevate the thermal properties of the Eu²⁺ doped phosphors. The as-prepared NaSr(PO₃)₃:Eu²⁺ phosphors show a strong temperature dependent performance, which can serve as a promising temperature sensor.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.1
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• pp.30-38
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• 2022

According to the United Nations Convention on the Law of the Sea (Article 94), the flag state must fulfill its overall role to ensure maritime safety and operate the ship inspection system as a related measure. The Korean government (Ministry of Ocean and Fisheries) has implemented policies for reducing marine accidents to promote maritime safety; however, the target goal has not been achieved. The ship inspection system is a measure to prevent marine accidents, and for the effective operation of the system, a sufficient understanding of the origin of the ship inspection system is required. In this study, the trend of the international ship inspection system was identified by analyzing ship inspection system origins and the history of the system's paradigm shift. The recent international ship inspection system paradigm confirms international standardization and the active safety management of ship companies are becoming increasingly prominent. Based on this, the introduction of the 'PDCA cycle-based self-inspection system' is presented to the current domestic ship inspection system. This is a new type of inspection system that establishes the roles of interested parties based on the basic philosophy of the ISO 9000 series to improve the ef ectiveness of maritime safety. Additionally, the necessity for a non-face-to-face ship inspection system has emerged because of the COVID-19 pandemic. Hence, the transition to a 'mobile application-based ship inspection system' is proposed to accommodate the rapid development of information communications technology.

• Journal of Korea Entertainment Industry Association
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• v.15 no.1
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• pp.27-38
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• 2021

Non-Contact society has arrived due to social distinctions by COVID 19 pandemic. The arrival of the era of non-contact is having a profound impact on educational activities as well as on our social and economic lives. In response to the pandemic situation universities and all other educational institutions have implemented non-contact online classes. In particular arts physical educations and other practical classes are experiencing many difficulties due to the limited environment caused by social distancing from COVID 19 pandemic. Vocal classes are undergoing a transition mainly from 1:1 individual face-to-face lessons or group teaching methods to the non-contact era of online teaching or lesson methods. It is necessary to look at the direction of non-face-to-face practical classes in preparation for accelerated educational innovation. Edu-tech, which innovates technology in the wake of the age of non-contact after COVID 19 pandemic is expected to begin in earnest at school sites in Korea which have remained in the traditional way of education. The purpose of this study is to effectively non-contact vocal instructional methods by cogitating the current state of higher practical education and vocal classes in Korea. In addition, This study conducted two components of satisfied instructions such as 'Priorlearning of monitoring of recorded singing', and 'Immediate analyzing of various vocal contents and supplementary lessons of music theory' with a research on the peos and cons of non-face-to-face vocal class. Over a period of time, The effective non-contact of vocal instructional methods is in need to supplement non-face-to-face vocal class problems and further research and system construction with non-face-to-face vocal class's pros and cons to construct high-quality lecture contents is warranted.