• Journal of Institute of Control, Robotics and Systems
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• v.22 no.11
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• pp.888-894
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• 2016

This paper presents the kinematic and dynamic analysis of the robot arm for inspection and rescue operations. The inspection robot arm has Pitch-Pitch-Pitch-Yaw motion for an optimal and stable view of the camera installed at the end of the manipulator. The rescue operation robot arm has Yaw-Pitch-Pitch-Roll motion to handle heavy tools. Additionally, both robot arms are waterproof, as they use the triple-layer O-ring. Furthermore, the dynamic equation including the damping force due to the mechanical seal for waterproofness was derived by using the Newton-Euler method. A control system using the ARM processor was developed and introduced in this paper, and its performance was verified through experiments.

• Particle and aerosol research
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• v.13 no.4
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• pp.173-182
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• 2017

An Eulerian-Lagrangin approach is used to compute particle dispersion from a power plant chimney. For air flow, three-dimensional incompressible filtered Navier-Stokes equations are solved with a subgrid-scale model by integrating the Newton's equation, while the dispersed phase is solved in a Lagrangian framework. The velocity ratios between crossflow and a jet of 0.455 and 0.727 are considered. Flow fields and particle distribution of both cases are evaluated and compared. When the velocity ratio is 0.455, it demonstrates a Kelvin-Helmholtz vortex structure above the chimney caused by the interaction between crossflow and a jet, whereas the other case shows flow structures at the top of the chimney collapsed by fast crossflow. Also, complex wake structures cause different particle distributions behind the chimney. The case with the velocity ratio of 0.727 demonstrates strong particle concentration at the vortical region, whereas the case with the velocity ratio of 0.455 shows more dispersive particle distribution. The simulation result shows similar tendency to the experimental result.

• Journal of The Korean Association For Science Education
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• v.10 no.1
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• pp.57-64
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• 1990

In this study, novices' protocols were investigated on the basis of Mayer's analysis of mathematical problem solving. These protocols were obtained by Jae-Sool Kwon and Seong-Wang Lee(1988) by means of thinking aloud while 20 sophomore students in a department of physics education were solving physics problems on Newton's low of motion. The results of investiqation are as follows; (1) We proposed an effective method in analyzing protocols on physics porblem solving (2) We could find the defective types of knowledge of individuals who got an incorrect solution, through analyzing the cause of failure individually (3) The fact that many students considered first the frictional force as muntiplying the coefficient of friction by perpendicular force rather than as resistance of motion, was found And students' misconception on the coefficient of friction was found. (4) If such analyses of test items and protocols are used in physics education, they will be very useful for finding the faults of problem-solving process, and for setting and scoring subjective problems in physics

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.11a
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• pp.29-34
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• 2004

Numerical and experimental studies on pipeline laying for intake Deep Ocean Water are carried out. In the numerical study, an implicit finite difference algorithm is employed for three-dimensional pipe equations. Fluid non-linearity and bending stiffness are considered and solved by Newton-Raphson iteration. Seabed is modeled as elastic foundation with linear spring and damper. Top tension and general configuration of pipeline at a depth are predicted. It is found that control for tension to prevent being large curvature of pipeline is needed on th steep seabed and, it should be considered 23.5 ton of tension at a top of pipe on the process of pipeline laying at 400m of water depth The largest top tension of pipe on condition of the beam sea during pipe laying is shown from the experiment. The results of this study can be contributed to the design of pipeline laying for upwelling deep ocean water.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.34.2-34.2
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• 2016

X-ray cavities are typically detected as surface brightness depression in X-ray diffuse emission from hot gas in high resolution X-ray images (i.e., Chandra and XMM-Newton). Showing the coincidence of location with radio jets, X-ray cavities imply that the radio jets interact with interstellar/intergalactic medium. It is important to understand them since they can be a clue of understanding AGN feedback to their host galaxies. To understand the physics of the AGN feedback, X-ray cavity has been actively studied while there are only a few statistical studies on X-ray cavity based on small or incomplete samples. Hence, a systematic study with a large sample is needed. With the condition of sufficient X-ray photons to detect surface brightness depression, we constructed a large sample of 133 galaxy clusters, galaxy groups, and individual galaxies to investigate X-ray cavities. We detected 201 cavities from 94 objects using two detection methods (i.e., beta-modeling and unsharp masking method), and confirmed the cavity size-distance relation over a large dynamical range. The size-distance relation does not vary for different environments (i.e., galaxy cluster, groups, and individual galaxies), suggesting that there is little environmental effect on the formation of X-ray cavity.

• Journal of the Korean Institute of Landscape Architecture
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• v.27 no.5
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• pp.170-180
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• 2000

The surface-drainage system, which consists of bio-swale and detention-infiltration Basins and carries out the function of temporary detention-infiltration of runoff, is defined as the "natural drainage system". It is an environmentally sound and economically beneficial practice to reduce run-off by retaining it in swales as much as possible and letting run-off infiltrate into the ground. In order to estimate appropriate capacity of swales, it is necessary to know how long will it take for certain depths of water to infiltrate. The ponding times, or infiltration times, of various depths and of various soil textures, could be estimated with the Green-Ampt Infiltration Model. Included soil textures are loamy sand, sandy loam, loam, silty loam, sandy clay loam and clay loam. Ponding depths are from 10cm to 100cm intervals. Newton-Raphson method is used for the solution of the Green-Ampt equation by a computer program. The computer program was written with the FORTRAN Developer 4.0 v.. Selected ponding depth is acceptable when the sum of the ponding time and the breeding time of mosquitoes is less than the tolerance period of innundation of grasses and trees.and trees.

• Magazine of the Korea Concrete Institute
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• v.8 no.2
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• pp.119-127
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• 1996

Objection of this study is to present the three-dimensional material nonlinear analysis of reinforced concrete. A concrete is idealized with three-dimensional 16-node solid element including triaxial nonlinear stress-strain behavior, cracking, crushing and strain softening: a steel with three-dimensional 3 node truss element including elastic-plastic behavior with strain hardening. The cracked shear retention factor is introduced to estimate the effective shear modulus con sidering aggregate interlock after c:racking and a modified newton method is used to obtain a nu merical solution. Numerical results in a gauss point is displayed graphically. Numerical examples of Krahl's reinforced concrete beam and Hedgreds shell are selected to compare with the experimental and numerical results.

• Journal of Power Electronics
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• v.14 no.3
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• pp.488-498
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• 2014

This paper presents an implementation of selective harmonic elimination (SHE) modulation for a single-phase 13-level transistor-clamped H-bridge (TCHB) based cascaded multilevel inverter. To determine the optimum switching angle of the SHE equations, the Newton-Raphson method is used in solving the transcendental equation describing the fundamental and harmonic components. The proposed SHE scheme used the relationship between the angles and a sinusoidal reference waveform based on voltage-angle equal criteria. The proposed SHE scheme is evaluated through simulation and experimental results. The digital modulator based-SHE scheme using a field-programmable gate array (FPGA) is described and has been implemented on an Altera DE2 board. The proposed SHE is efficient in eliminating the $3^{rd}$, $5^{th}$, $7^{th}$, $9^{th}$ and $11^{th}$ order harmonics, which validates the analytical results. From the results, it can be seen that the adopted 13-level inverter produces a higher quality with a better harmonic profile and sinusoidal shape of the stepped output waveform.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2009.06a
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• pp.287-288
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• 2009

In this paper we developed positioning algorithm considering distributed energy resource of ocean side by load flow calculation using Newton-Rhapson method.

• Nuclear Engineering and Technology
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• v.49 no.6
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• pp.1358-1367
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• 2017

The data integration with modeled predictions (DIMP) model is a promising inverse radiation transport method for solving the special nuclear material (SNM) holdup problem. Unlike previous methods, DIMP is a completely passive nondestructive assay technique that requires no initial assumptions regarding the source distribution or active measurement time. DIMP predicts the most probable source location and distribution through Bayesian inference and quasi-Newtonian optimization of predicted detector responses (using the adjoint transport solution) with measured responses. DIMP performs well with forward hemispherical collimation and unshielded measurements, but several considerations are required when using narrow-view collimated detectors. DIMP converged well to the correct source distribution as the number of synthetic responses increased. DIMP also performed well for the first experimental validation exercise after applying a collimation factor, and sufficiently reducing the source search volume's extent to prevent the optimizer from getting stuck in local minima. DIMP's simple point detector response function (DRF) is being improved to address coplanar false positive/negative responses, and an angular DRF is being considered for integration with the next version of DIMP to account for highly collimated responses. Overall, DIMP shows promise for solving the SNM holdup inverse problem, especially once an improved optimization algorithm is implemented.