• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1598-1602
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• 2003

The parallel-type mechanism provides more accurate and stiff motion than the serial-type mechanism. However, in case of using the haptic device, the performance of the force reflection can be deteriorated due to the singular points existing in workspace. In this paper, we propose a redundantly actuated parallel 3-DOF haptic device, which is singularity-free in the workspace and has an improved force reflection capability. In addition, we propose a new force distribution algorithm, which can reflect force of both high and low resolution, using two sets of actuator with different size. Redundant actuators are attached to the base frame in order to minimize the inertia of the system. Moreover, a wire and gear reduction system is employed to achieve high force reflection along with soft feeling. We confirm the performance of the force reflection capability throughout simulation.

• The Journal of Korean Association of Computer Education
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• v.22 no.5
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• pp.27-37
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• 2019

In this study, for the purpose of reflection level analysis of high school students in HW design learning which is based on online simulation, we carried out 5 lessons of HW learning and analyzed there reflection levels for 5 individual time of reflection content. The reflection level analysis results for each time of learning shows that the reflection level of the $3^{rd}$ time learning of D-Flip Flop is the highest score with 1.23. The correlation analysis result between the reflection contents presents that high positive correlation between learning content and task resolving method(r=.781, p<.01), and negative design correlation between task resolving method and alternative resolving method. The HW learning satisfaction survey result shows 4.2, and most of the participant students provided opinions that the HW design learning is required and current learning contents is a bit difficult to follow. We could recognize HW design learning is required to have composition of curriculum with basic and advanced contents, and on-off lines combined.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.12a
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• pp.103-106
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• 2006

Semiconductor laser diode has a reflective facet in a both-ends side fundamentally. Laser performance for improving, Anti-Reflection and High-reflection coating on the facet of semiconductor laser diode. To prevent internal feedback from both facets for realizing superluminescent diode and reducing the reflection-induced intensity noise of laser diode, it's key techniques are AR/HR coatings. In the study AR coating film were manufactured by Ion-Assisted Deposition(IAD) system. Then manufactured coating film measurement electrical properties(L-I-V, Se, Resistor) and Optical properties (wavelength FFP)

• Journal of the Korean School Mathematics Society
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• v.24 no.4
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• pp.369-390
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• 2021

It would be reasonable as a teacher to make efforts not only to reflect on the class on their own but also to improve the teacher' teaching e pertise by reflecting on the class with fellow teachers through lesson reflection sharing. This paper attempted to develop a lesson reflective framework that can provide standards and focus for lesson reflection and lesson sharing. First, based on the class evaluation criteria of previous studies, class reflection elements and a draft of lesson reflection were prepared. In a class conducted on 27 third graders at C High School where the co-researcher worked as a teacher, four peer teachers at the same high school were required to write personal opinions on the class based on the draft of lesson reflection. Based on this, lesson sharing was conducted, and modifications of the lesson reflection framework were developed by analyzing the case of class sharing. The implications of this paper indicate the need to clarify the perspective of viewing the lesson by sharing the intention of each question in advance. In addition to writing lesson reflections, it is necessary to share classes simultaneously.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.11
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• pp.1473-1480
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• 1999

In the case of Impingement of plane moving shock wave over concave or convex double wedges (pseudo-stationary flow) and cylindrical walls (truly non-stationary flow), it Is expected that there are transitions from regular reflection to Mach reflection or vice versa In shock wave reflections. In these connections, it is necessary to verify the various of reflection process and transition angle for the reflection problems In double wedges, and to verify the transition angle, effects of curvature radius and initial wall angle on it for the reflection problems In cylindrical walls. Especially, we focused our attention to confirm the existence of hysteresis phenomenon induced by the different transition processes, and Neumann paradox, which is a small discrepancy between theoretical and experimental transition angles. Experiments were carried out by using the shock tube of $6{\times}6cm^2$, and high speed photographic technique consisted of delay unit, triggering system, light source of Xe lamp and so on was used for flow visualization.

• Korean Journal of Optics and Photonics
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• v.23 no.1
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• pp.36-41
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• 2012

Total external reflection (TER), which does not occur on a dielectric interface, is a unique feature of surface plasmon-polaritons (SPP). We propose an SPP-TER waveguide structure consisting of low-index dielectric nanocore covered with high-index dielectric on a flat metal surface. The SPP mode confined in the nanocore by the TER effect has a mode size much smaller than wavelength scale. Numerical comparison of mode characteristics between the SPP-TER waveguides and other total-internal-reflection-based waveguides such as metal or high-index dielectric nanowires show that the SPP-TER structures can possess higher modal gain for applications of nanocavity lasers.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.807-814
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• 2004

Land seismic reflection survey has been increasingly demanded in various civil engineering works because of its own ability to delineate layers, water table, to detect cavities or fracture zones, to estimate seismic velocities of each layer. However, our shallow subsurface structures are very complex. The relatively thin layer(mostly soil) to the wavelength directly followed by a basic rock with high impedance used to generate complicated surface waves, kind of channel waves with high amplitude that is dominate in entire seismograms and hence the useful reflection events will be almost hopelessly immersed in the undesired surface waves. Thus, it would seem that the use of traditional seismic survey could not be likely to provide in itself a satisfactory information about our exploration targets. This paper hence introduces an efficient measuring strategy illustrating a properly controlled arrangement of the vertical single force sources commonly used, yielding a very sharply elongated form of P-energy with a minimum of S radiation energy, what we call, P-beam source. Abundant experiments of physical modeling showed that in that way the surface waves could be enormously reduced and the reflection events would be additive and thus reinforced. Examples of field data are also illustrated. The contribution of P-beam source will be great in civil engineering area as well as in general geological exploration area.

• 한국초전도학회:학술대회논문집
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• v.10
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• pp.141-144
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• 2000

We report on the influence of d-wave pairing symmetry in high-T$_c$ superconductor by tunneling spectroscopy. The zerobias conductance peak(ZBCP) which is produced by tunneling through the ab-plane is observed on both of metal Au/YBa$_2$Cu$_3$O$_y$(N/S) tunnel junctions and ferromagnet Co/Au/ YBa$_2$Cu$_3$O$_y$(F/N/S) tunnel junctions. The effects of Andreev reflection on the differential conductance of each junctions are dependent on the tunnel direction. For the S/N/F junction, it appears the suppression of the ZBCP due to the suppression of Andreev reflection at the interface between a ferromagnetic material and a d-wave superconductor. By comparing these experimental results with recent theoretical works on Andreev reflection, the existence of Andreev bound state is verified in high-T$_c$ superconductor, due to the d-wave symmetry of the pair potential.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.215-218
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• 2003

We have developed a reflective 3.5" QVGA color TFT-LCD with high reflection within viewing angle. For this, We have introduced new pixel design and asymmetric reflector. Based on these technical concepts, we get a high aperture ratio of 93.5% and much higher reflection up to 64% with a 3.5" prototype panel.

• Journal of the Korean Geophysical Society
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• v.2 no.4
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• pp.241-250
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• 1999

Reflection coefficients of the seafloor have been calculated from the amplitude ratio of secondary to primary water bottom reflection in seismic data obtained from Bransfield Strait, Antarctic Peninsula. Test processing for the coefficients shows that moving average is effective to reduce severe fluctuation of the coefficient measured at each point. Relationship between the coefficients and the properties of water bottom is analyzed to illuminate geological environment. In the central Bransfield Basin, the magnitude of reflection coefficients decreases as it is distant from the sedimentary sources. Reflection coefficients range from 0.12 to 0.2 near the continental slope of the basin, and from 0.1 to 0.12 in the basin floor. In the western Bransfield basin, reflection coefficients between 0.2 to 0.3 are obtained from the area eroded by glacial movement. On the volcanic structures near Deception Island, the coefficients show relatively high values more than 0.2. Paleo-geological structures uplifted by tectonic movement and outcropped by glacial erosion have relatively high coefficients.