• Journal of Internet of Things and Convergence
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• v.6 no.4
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• pp.81-87
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• 2020

This paper creates a standard node for acquiring sensor data from various industrial sensors (IoT/non-IoT) for the establishment of Smart Factory Digital Twin, and provides inter-compatible data by linking zones by group/process to secure data stability and to ensure the digital twin (Digital Twin) of Smart Factory. The process of the Zone Master platform contains interface specifications to define sensor objects and how sensor interactions between independent systems are performed and carries out individual policies for unique data exchange rules. The interface for execution control of the Zone Master Platform processor provides system management, declaration management for public-subscribe, object management for registering and communicating status information of sensor objects, ownership management for property ownership sharing, time management for data synchronization, and data distribution management for Route information on data exchange.

• Journal of IKEEE
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• v.26 no.4
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• pp.596-601
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• 2022

The application of the EGR system is increasing according to the recent trend of conversion to green-ships. EGR blower, one of the core parts of the EGR, consists of aerodynamic system and e-motor and inverter and etc. For the e-motor, a permanent magnet type synchronous motor with high energy density and excellent efficiency is applied recently. Small and medium-sized enterprises trying to develop the e-motors, however, for marine inverters mostly developed by global advanced companies due to the rigid classification certification and technical difficulties. One of disadvantage of universal inverters is that when optimal control fails, it is difficult to find the cause from user's point of view. Therefore, in this study, optimal controllers(Current vector contol and Tracking observer) for SPMSM for EGR blower was designed and verified to analyze the causes of failure of optimal control of universal inverter.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.489-489
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• 2023

최근 유량 측정을 위해 사용되는 ADCP를 통해 부가적으로 측정되는 초음파산란도 자료를 활용하여 부유사농도를 측정하는 연구가 수행되고 있다. 이에 국내에서는 국가하천에 설치되어 있는 자동유량관측소의 초음파산란도를 활용하여 연속적인 부유사농도를 측정하는 연구가 수행되고 있다. 이를 통해 10분 단위로 연속적인 유사량 자료를 생산할 수 있을 것으로 기대되며, 현재 유사량 측정결과의 제공을 위해 사용되는 유량-유사량 관계곡선의 산포로 인한 신뢰도 문제를 개선할 수 있을 것으로 기대되고 있다. 그러나, 이미 설치된 자동유량관측소의 H-ADCP 원시데이터를 활용하여 다지점에서 부유사농도를 측정에 대한 분석을 수행하기 위해서는 초음파산란도의 보정, 관계식 개발, 관계식 적용을 통한 유사량 측정 결과의 분석을 위한 소프트웨어 개발이 필요하다. 이에 본 연구에서는 초음파산란도 자료를 이용하여 부유사농도를 분석할 수 있는 소프트웨어 개발하고자 하였다. 개발된 소프트웨어는 Microsoft Visual Studio를 이용하여 C# 언어를 사용하여 개발하였으며, ComponentOne 라이브러리를 활용하여 그래픽 사용자 인터페이스(GUI)를 구현하였다. 소프트웨어의 구성은 H-ADCP 원시자료와 실측 부유사농도 자료와의 시간동기화를 통해 동일시간에서 측정된 자료를 획득, 초음파산란도의 보정과 지표로 활용할 초음파산란도의 측정영역 분석, 초음파산란도-부유사농도와의 다중 회귀를 통한 관계식 개발 및 통계 분석결과 도출, 관계식을 활용한 부유사농도 계산을 수행할 수 있도록 구성하였다. 본 연구를 통해 개발된 소프트웨어를 통해 추후에 시범적용 예정인 자동유량관측소의 초음파산란도를 활용 부유사농도 측정 방법에 대한 분석 효율성을 향상시키고, 지속적인 개선을 통해서 실제 실무에서 활용이 가능할 것으로 기대된다.

• Journal of Korean Library and Information Science Society
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• v.55 no.1
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• pp.173-192
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• 2024

Through a survey of college students, this study explained the process and aspects of how Generation Z interacted with information while collaborating on a daily basis. Applying the Radical Change Theory, the study investigated the platforms through which university students engaged in challenges and their information behaviors. University students primarily participated in challenges using platforms such as Instagram and Naver Blog. In terms of changes in information seeking, which is the first type of information seeking in the theory, a wide and diverse range of information behaviors were observed, with the way of searching for information being quite different from when the digital age arrived 10 years ago. Information sources included not only digitalized ones but also traditional sources such as printed materials and personal contacts. The utilization of various media types was prominent, and collaborative efforts were voluntarily undertaken for challenges. In terms of changing perspectives, type 2 of information behavior, the main motivation for acquiring information and securing knowledge led to participation in the challenge. Participants exhibited a sense of community consciousness, including mutual influence awareness, social participation consciousness, and emotional connection.

• Journal of Aerospace System Engineering
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• v.18 no.3
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• pp.27-33
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• 2024

According to the success of the Nuri Space Launch Vehicle (KSLV-II) and the development goal of the next generation space launch vehicle (KSLV-III), it is expected that the domestic geostationary satellite capability will be increased from (1 to 3.7) ton. Also, it is predicted that substantial ability of about 1 ton can be provided for the space exploration of the Moon, Mars, asteroids, etc. The Goheung space launch site is optimized for sun-synchronous small satellites, and due to the essential precondition that the launch trajectory does not impinge another country's sovereign airspace, it is not satisfactory as a geostationary satellite launching site. Its latitude also requires more energy to shape the rotating orbital plane from the initial injection status. This results in a decreasing factor of economic feasibility, including the operating complexity. Therefore, in parallel with the development of a next generation space launch vehicle, the practical process for acquisition of oversea land or sea space launch site near the Earth's equator and research for the optimization of orbiting methods of geostationary satellite injection must be continued.

• The Journal of Korean Society for Radiation Therapy
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• v.22 no.2
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• pp.145-153
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• 2010

Purpose: To accurately define internal target volume (ITV) for treatment of moving target considering tumor size and respiratory motion, we quantitatively investigated volume of target volume delineated on CT images from helical CT and 4D CT scans. Materials and Methods: CT images for a 1D moving phantom with diameters of 1.5, 3, and 6 cm, acryl spheres were acquired using a LightSpeed $RT^{16}CT$ simulator. To analyze effect of tumor motion on target delineation, the CT image of the phantoms with various moving distances of 1~4 cm, and respiratory periods of 3~6 seconds, were acquired. For investigating the accuracy of the target trajectory, volume ratio of the target volumes delineated on CT images to expected volumes calculated with diameters of spherical phantom and moving distance were compared. Results: Ratio$_{helical}$ for the diameter of 1, 5, 3, and 6 cm targets were $32{\pm}14%$, $45{\pm}14%$, and $58{\pm}13%$, respectively, in the all cases. As to 4DCT, RatioMIP were $98{\pm}8%$, $97{\pm}5%$, and $95{\pm}1%$, respectively. Conclusion: The target volumes delineated on MIP images well represented the target trajectory, in comparison to those from helical CT. Target volume delineation on MIP images might be reasonable especially for treatment of early stage lung cancer, with meticulous attention to small size target, large respiratory motion, and fast breathing.

• The KIPS Transactions:PartC
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• v.16C no.6
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• pp.737-746
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• 2009

Given the increased interest in ubiquitous computing, wireless sensor network has been researched widely. The localization service which provides the location information of mobile user, is one of important service provided by sensor network. Many methods to obtain the location information of mobile user have been proposed. However, these methods were developed for only one mobile user so that it is hard to extend for multiple mobile users. If multiple mobile users start the localization process concurrently, there could be interference of beacon or ultrasound that each mobile user transmits. In the paper, we propose APL(Adaptive Power Control based Resource Allocation Technique for Efficient Localization Technique), the localization technique for multiple mobile nodes based on adaptive power control in mobile wireless sensor networks. In APL, collision of localization between sensor nodes is prevented by forcing the mobile node to get the permission of localization from anchor nodes. For this, we use RTS(Ready To Send) packet type for localization initiation by mobile node and CTS(Clear To Send) packet type for localization grant by anchor node. NTS(Not To Send) packet type is used to reject localization by anchor node for interference avoidance and STS(Start To Send) for synchronization between 모anchor nodes. At last, the power level of sensor node is controled adaptively to minimize the affected area. The experimental result shows that the number of interference between nodes are increased in proportion to the number of mobile nodes and APL provides efficient localization.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.6
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• pp.465-474
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• 2014

To validate the accuracy of the boiling heat flux partitioning model, an experiment was performed to investigate how the wall heat flux is divided into the three heat transfer modes of evaporation, quenching, and single-phase convection during subcooled nucleate boiling on a vertical wall. For the experimental partitioning of the wall heat flux, the wall heat flux and liquid-vapor distributions were simultaneously obtained using synchronized infrared thermometry and the total reflection technique. Boiling experiments of water with subcooling of $10^{\circ}C$ were conducted under atmospheric pressure, and the results obtained at the wall superheat of $12^{\circ}C$ and average heat flux of $283kW/m^2$were analyzed. There was a large difference in the heat flux partitioning results between the experiment and correlation, and the bubble departure diameter and bubble influence factor, which account for a portion of the surrounding superheated liquid layer detached by the departure of a bubble, were found to be important fundamental boiling parameters.

• Journal of Music and Human Behavior
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• v.10 no.2
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• pp.35-54
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• 2013

The purpose of this study was to examine how Korean music therapy students experience growth under clinical supervision. The investigator conducted in-depth qualitative interviews with 9 students from 3 different universities in Seoul who had at least three semesters of clinical supervision. Data was analyzed using a modified grounded theory approach to construct the growth experience of music therapy supervisees. Results suggest that growth can be understood in terms of both personal and professional domains and includes four types of experiences: growth hindering, fostering, mediating, and revealing. In the personal domain, hindering factors are defensiveness, narcissistic trauma, avoidance and anxiety whereas growth fostering and mediating factors include reflection on self, musical self, unconscious drives and conflicting issues as well as self-driven problem solving skills. As a result, growth in the personal domain is associated with increased self-acceptance and self-awareness. Growth in the professional domain is hindered by having trust issues, performance anxiety, identity crisis, and being hypersensitive to the judgment of others. On the other hand, growth is fostered and mediated by opening the self and interacting more with others, building trusting relationships with peers and supervisors, and establishing a new relationship with music, which leads to improved attitude, increased motivation, and more efficient and effective training.

• The Journal of the Korea Contents Association
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• v.16 no.10
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• pp.382-392
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• 2016

This study organize a self-directed learning in complex structures. And based on this, It was developed self-directed learning scale for university students. It was a analyzing literature and reviewing previous studies for developed scale. Therefore, Self-directed learning model was configured into motives, performance behaviors, and learning management behaviors. On the basis of this, the present study constructed 19 sub-factors and developed 114 scale items. First, a preliminary scale was developed and its reliability was assessed by administering the scale to 128 students attending A university. The result showed that the reliability of every sub-factor was good and, therefore, the scale was developed with no item removed. To verify the validity of the scale, this study evaluated reliability and construct validity by administering the scale to 674 students going to A university. The reliability and validity of all sub-factors were found to be good. A confirmatory factor analysis was performed to verify construct validity and the result revealed that the first model was not an appropriate model. For this reason, the first model was modified once by taking the model modification index into account and it was found that ${\chi}^2$ (563.254), CFI=.963, NFI=.951, RMSEA=.064. Thus, the model was verified as a valid model. The results of this study imply that it is possible to point out learners' weaknesses and strengths by measuring activities taking place in the learning process in detail.