• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.52-55
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• 2004

In this paper, we examined channel charge which occurs in electron accumulation after electron velocity saturation. Generally, short gate GaAs MESFET show, saturated electron velocity leading to current salutation. When electron velocity is saturated, deletion layer is stil open channel and it play a key role in deciding saturation current mode we proposed channel charge model in channel after electron velocity saturation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.1
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• pp.42-47
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• 2010

The power burden of high-$T_c$ superconducting (HTSC) elements comprising superconducting fault current limiter (SFCL) using magnetic coupling of shunt reactors was analyzed. The magnetically coupled shunt reactors play a role in distributing the even power burden between HTSC elements comprising the SFCL, which contributes to the effective current limiting and recovery characteristics of the SFCL. It was confirmed through the comparative analysis on the SFCLs with both the magnetically coupled and the magnetically uncoupled shunt reactors that the magnetically coupled shunt reactors could improve the SFCL's performance by equalizing the power burden of HTSC elements.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.3
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• pp.234-240
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• 2019

In this work, the magnetic arc reduction phenomena encountered in AC relay contacts were analyzed. To this end, arc duration, instantaneous voltage, and current changes due to changes in the magnetic field were observed. The arc generated at the contact point was affected by the magnitude of the applied magnetic field; the voltage and current waveforms rapidly intersected, resulting in a decrease in arc duration and arc energy. Furthermore, the orientation of the N pole of the magnetic field was found to play a role in the effectiveness of potential arc prevention.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.4
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• pp.755-762
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• 2021

This study is a study for the utilization of marine information and communication technology of Masan port in order to play a pivotal role in the economy of Masan port as a base port for entering the southern coast area. It aims to examine the utilization of marine information technology to be pursued in the mid- to long-term based on the current status of Masan port and the ICT being applied.

• Progress in Superconductivity and Cryogenics
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• v.25 no.2
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• pp.1-4
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• 2023

Over the past decade, the exploration of high-temperature superconductivity and the discovery of a wide range of exotic superconducting states in Fe-based materials have propelled condensed matter physics research to new frontiers. These materials exhibit intriguing phenomena arising from their multiband electronic structure, strongly orbital-dependent effects, extremely small Fermi energy, electronic nematicity, and topological aspects. Among the various factors influencing their superconducting properties, high magnetic fields play a crucial role as a control knob capable of disrupting the subtle balance between the spin, charge, lattice, and orbital degrees of freedom, leading to the emergence of various exotic superconducting states. In this review, we provide an overview of the current understanding of the exotic superconducting states observed in Fe-based superconductors, with a particular focus on FeSe and Sr₂VO₃FeAs, under the influence of high magnetic fields.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.6
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• pp.1371-1378
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• 2023

Kiosks are gaining popularity as an essential tool that offers unmanned services and payment systems, and their use is rapidly increasing in the service industry. However, the use of kiosks can be challenging for the elderly who are not accustomed to digital technology and touchscreens. Consequently, this study develops an educational program that utilizes metaverse technology to enhance the digital skills and kiosk service accessibility of older adults. This research has created an educational system that allows the elderly to learn digital skills and kiosk access through play.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.37 no.5
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• pp.476-485
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• 2024

Understanding the structure-property relationship in functional materials is crucial as microstructural features such as nano-precipitates, phase boundary, grain boundary segregation, and grain boundary phases play a key role in their functional properties. Atom probe tomography (APT) is an advanced analytical technique that allows for the three-dimensional (3D) mapping of atomic distributions and the precise determination of local chemical compositions in materials. Moreover, it offers sub-nanometer spatial resolution and chemical sensitivity at the tens of parts per million (ppm) level. Owing to its unique capabilities, this technique has been employed to uncover the 3D elemental distributions in a wide range of materials, including alloys, semiconductors, nanomaterials, and even biomaterials. In this paper, various kinds of examples are introduced for elucidating structure-property relationships on functional materials by utilizing the atom probe tomography.

• International Journal of Computer Science & Network Security
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• v.22 no.10
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• pp.322-332
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• 2022

The current research aimed to ascertain the effectiveness of the early intervention program based on electronic games in developing the visual perception of children with intellectual disabilities within the age group of (2-5) years, using the quasi-experimental approach with one group, and the study sample consisted of (11) children with disabilities. Simple and medium intellectuals enrolled in the early intervention program at the Successful Communication Center for Day Care in Makkah Al-Mukarramah and were deliberately selected. To achieve the research objectives, the researchers prepared and applied the visual perception scale after ensuring its validity and stability. Three electronic games were also designed and applied to the sample for (17) sessions. The results showed the effectiveness of the electronic games program in developing the visual perception of children with intellectual disabilities within the age group (2-5) years and maintaining this improvement over time. Where the results showed that there were statistically significant differences at the level (α = 0.05) between the grades of the group children in the pre and post-measurements on the visual perception skills scale for children with intellectual disabilities in the post-measurement after applying the program, in favor of the post measurement. The results also showed that there were no statistically significant differences at the level (α = 0.05) between the grades of the group children in the two post and follow-up measurements on the visual perception skills scale for children with intellectual disabilities in the follow-up measurement which indicates the long-term impact of the program. The researchers recommend the necessity of activating educational programs based on various electronic games to develop the visual perception of children with intellectual disabilities and employ them effectively in the educational process for children with intellectual disabilities.

• Journal of Aerospace System Engineering
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• v.17 no.6
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• pp.35-45
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• 2023

In this paper, we analyze the influence of indirect lightning strikes based on the structure of shielded cables used in an aircraft and propose a cable structure to enhance shielding effectiveness. Cables in an aircraft account for the largest proportion among components and play a crucial role in connecting aircraft frames and electronic devices; thus, making them highly influential. In particular, indirect lightning strike noise can lead to malfunctions and cause damage in aircraft electronic equipment, making the utilization of shielded cables essential for mitigating damage caused by indirect lightning strike noise. We conducted an analysis of the impact of indirect lightning strikes on aircraft shielded cables considering factors, such as the presence of shielding layers, core, and insulation in the cable structure. Furthermore, we validated our findings through simulations and experiments by applying the internationally recognized standard for indirect lightning, RTCA DO-160G Sec. 22.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.628-632
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• 2003

An intelligent miniature humanoid robot system is designed and implemented as a platform for researching walking algorithm. The robot system consists of a mechanical robot body, a control system, a sensor system, and a human interface system. The robot has 6 dofs per leg, 3 dofs per arm, and 2 dofs for a neck, so it has total of 20 dofs to have dexterous motion capability. For the control system, a supervisory controller runs on a remote host computer to plan high level robot actions based on the vision sensor data, a main controller implemented with a DSP chip generates walking trajectories for the robot to perform the commanded action, and an auxiliary controller implemented with an FPGA chip controls 20 actuators. The robot has three types of sensors. A two-axis acceleration sensor and eight force sensing resistors for acquiring information on walking status of the robot, and a color CCD camera for acquiring information on the surroundings. As an example of an intelligent robot action, some experiments on playing soccer are performed.