• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.1
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• pp.60-64
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• 2020

In this study, to develop angle ring pressboards for high voltage transformers, the radius and thickness are modified under the conditions of temperature and humidity. In particular, a pressboard with a thickness of 6 mm and a radius at the angled part were investigated based on the simulation of the principal stress from the angled optimization profile shape. As a result, by the appropriate application of a higher temperature, the solid insulation can be improved to reduce the moisture content for an optimized profile angle of a high voltage transformer. This also results in the improvement of the safety factor by 25%. It is determined that the electrical insulation properties of pressboards in high voltage transformers can be enhanced by improving their properties.

• Journal of the Korean Society of Safety
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• v.25 no.1
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• pp.65-71
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• 2010

In this study, a series of finite element analysis using LUSAS were performed in order to assess the quantitative effects of repair and retrofit of stringer in steel plate girder railway bridge with fatigue cracks. And cutoff types of end part of upper flange were considered as right-angled type and round-angled type. Also, as a method of repair and retrofit of fatigue cracks in stringer, perforation of stop-hole and installation of bracket were considered. From the analysis result, it was possible to assess the fatigue safety and fatigue life of stringer with fatigue cracks, and to estimate the stress intensity factor range in cut-off part of stringer using J-integral method. Also, according to the method of perforation of stop-hole and installation of bracket, it was possible to calculate the crack propagation life at the cut-off part of stringer.

• The KSFM Journal of Fluid Machinery
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• v.9 no.6 s.39
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• pp.9-16
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• 2006

Performance characteristics of an axial flow fan having distorted inlet flow have been investigated using numerical analysis as well as experiment. Two kinds of hub-cap, rounded and right-angled front shape, are tested to investigate the effect of inlet flow distortion on the fan performance. Numerical solutions are validated in comparison with experimental data measured by a five-hole probe downstream of the fan rotor. It is found from the numerical results that non-uniform axial inlet velocity profile near the hub results in the change of inlet flow angle. Large recirculation flow upstream the fan rotor for the right-angled hub-cap induces a negative incidence, thus invokes separated flow on the blade surfaces and deteriorates the performance of fan rotor.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.113-116
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• 2006

In this paper, the fairing effects on the aerodynamics stability of basic plate-girder sections are investigated trough wind tunnel tests. As basis sections, two types of $\pi$-type shape sections with aspect ratios(D/B) of 1/5 and 1/10 are employed as the basic sections. And three types of triangular fairings are applied such as right-angled triangle(F1), inverted right-angled triangle(F2) and regular triangle(F3). The effects of attack angle on the dynamic response of each section are also investigated. As the results of experiments, fairings F2 is most effective to suppress flutter phenomenon or vortex induced vibration among three types of fairings.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.7 no.2
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• pp.95-104
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• 1996

The effects of involved parameters to the voltages induced at both ends of an angled two-wire transmission line are investigated for the incidence of an arbitrary plane wave. The minimum level of the induced voltages is found in case that both ends of the transmission line are terminated by the ma- tching loads and the azimuth angle of the incident wave is equal to the elevation angle. A graphical technique is also developed to estimate the induced voltages at the change of the wire radius or tilt angle between two wires.

• Journal of KSNVE
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• v.9 no.3
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• pp.509-516
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• 1999

The ESPI (Electronic Speckle Pattern Interferometry) algorithm has been simulated to calculate vibrational modes of a thin right-angled STS304 plate. The phase transformation of the reference wave of the ESPI is carried out only one time during vibration in order to clarify ESPI speckle patterns. Two dimensional vibrational modes are calculated from one ESPI pattern before vibration onset and two ESPI patterns during vibrations but with and without the phase transformation. The ESPI harmonic results are compared with those derived from the finite element method (FEM), and they agree very well. Additionally a phase unwrapping algorithm has been newly developed to derive a displacement map from an ESPI phase map.

• Bulletin of the Society of Naval Architects of Korea
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• v.20 no.2
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• pp.43-49
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• 1983

Stiffened plates, mostly used in the major part of ship and airplane structures, have been studied by various way-theoretical and experimental. In case of the fore and aft parts of the parallel middle body of ship structure, the stiffeners are not right-angled to the plate but acute angled. This paper presents the analysis of plates having included stiffeners by Finite Strip Method. The results of calculation show the influence of inclined angle which is less than $10^{\circ}$is ignorable. It is recommended that, when the inclined angle is over $20^{\circ}$, the section modulus of stiffener should be increased.

• 유체기계공업학회:학술대회논문집
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• 2003.12a
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• pp.627-630
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• 2003

This work presents a numerical procedure to optimize the shape of three-dimensional channel with angled ribs mounted on one of the walls to enhance turbulent heat transfer. The response surface method is used as an optimization technique with Reynolds-averaged Navier-Stokes analysis of flow and heat transfer. SST turbulence model is used as a turbulence closure. The width-to-height ratio of the rib, rib height-to-channel height ratio, pitch-to-rib height ratio and attack angle of the rib are chosen as design variables. The objective function is defined as a linear combination of heat-transfer and friction-loss related terms with weighting factor. D-optimal experimental design method is used to determine the data points. Optimum shapes of the channel have been obtained for the weighting factors in the range from 0.0 to 1.0.

• Structural Engineering and Mechanics
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• v.7 no.3
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• pp.331-344
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• 1999

This paper provides an analysis of the transient behaviour of a right-angled bent cantilever beam subjected to a suddenly applied force at its tip perpendicular to its plane. Based on a rigid, perfectly plastic material model, a double-hinge mechanism is required to complete the possible deformation under a rectangular force pulse (constant force applied for a finite duration) with a four-phase response mode. The kinematics of the various response phases are described and the partitioning of the input energy at the plastic hinges during the motion is evaluated.

• Communications for Statistical Applications and Methods
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• v.28 no.2
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• pp.161-169
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• 2021

The two-dimensional confusion matrix used in credit assessment, biostatistics, and many other fields consists of true positive, true negative, false positive, and false negative. Their rates, such as the true positive rate (TPR), true negative rate (TNR), false positive rate, and false negative rate, can be applied to measure its accuracy. In this study, we propose the TPR-TNR plot, a graphical method that can geometrically describe and explain these rates based on the confusion matrix. The proposed TPR-TNR plot consists of two right-angled triangles. We obtain that the TPR and TNR describe the acute angles of right-angled triangles in the plot. These acute angles can be used to determine optimal thresholds corresponding to lots of accuracy measures.