• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.58.4-58.4
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• 2019

We present the application of the Point Spread Function (PSF) deconvolution method to the astronomical Integral Field Unit (IFU) Spectroscopy data focus on the restoration of the galaxy kinematics. We apply the Lucy-Richardson deconvolution algorithm to the 2D image at each wavelength slice. We make a set of mock IFU data which resemble the IFU observation to the model galaxies with a diverse combination of surface brightness profile, S/N, line-of-sight geometry and Line-Of-Sight Velocity Distribution (LOSVD). Using the mock IFU data, we demonstrate that the algorithm can effectively recover the stellar kinematics of the galaxy. We also show that lambda_R_e, the proxy of the spin parameter can be correctly measured from the deconvolved IFU data. Implementation of the algorithm to the actual SDSS-IV MaNGA IFU survey data exhibits the noticeable difference on the 2D LOSVD, geometry, lambda_R_e. The algorithm can be applied to any other regular-grid IFS data to extract the PSF-deconvolved spatial information.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.2
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• pp.27-32
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• 2004

Absolute optical angle sensor is described that is an essentially digital opto-electronic device. Its purpose is to resolve the relative and absolute angle position of coded disk using Pseudorandom-code and Geometry-code. In this technique, the angular position of disk is determined in coarse sense first by Pseudorandom-code. A further fine angular position data based on Pixel count is obtained by Geometry-code which result 0.006$^{\circ}$ resolution of the system provided that 7 ${\mu}{\textrm}{m}$ line image sensor are used. The proposed technique is novel in a number of aspects, such that it has the non-contact reflective nature, high resolution of the system, relatively simple code pattern, and inherent digital nature of the sensor. And what is more the system can be easily modified to torque sensor by applying two coded disks in a manner that observe the difference in absolute angular displacement. The digital opto-electronic nature of the proposed sensor, along with its reporting of both torque and angle, makes the system ideal for use in intelligent vehicle systems. In this communication, we propose a technique that utilizes Pseudorandom-code and Geometry-code to determine accurate angular position of coded disk. We present the experimental results to demonstrate the validity of the idea.

• Journal of the Korean Society of Safety
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• v.16 no.1
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• pp.25-30
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• 2001

This paper studies the effect of vibration characteristics of tube line conveying fluid with the power steering system of bus. We modelled fluid-filled tube line using I-DEAS software to investigate vibration characteristics of the power steering tube line. And we obtained the natural frequency of tube line through finite element analysis. Analytic solutions were compared with experimental solutions to verify finite element model. We tested the tube line to examine an effect of pressure pulse by vane pump and variation of geometry of tube. From both the experimental results and the modeling results for vibration characteristics of the tube line conveying fluid, we confirmed that vibration characteristics induced by pulse propagated along the power steering tube line and resonance occurred around the natural frequency with pulse excitation.

• Transactions of Materials Processing
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• v.24 no.2
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• pp.107-114
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• 2015

The current study presents a geometric measurement and analysis of the section profile for a feature line surface on an automotive outer panel. A feature line surface is the geometry which is a visually noticeable creased line on a smooth panel. In the current study the section profile of a feature line surface is analyzed geometrically. The section profile on the real press panel was measured using a coordinate measuring machine. The section profiles from the CAD model and the real panel are aligned using the same coordinate system defined by two holes near the feature line. In the aligned section profiles the chord length and height of the curved part were measured and analyzed. The results show that the feature line surface on the real panel is doubled in width size.

• Communications of Mathematical Education
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• v.37 no.4
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• pp.635-652
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• 2023

This study conducts a comprehensive analysis of the curricular progression of the concepts and learning sequences of 'lines', specifically, 'line segments', 'straight lines', and 'rays', at the elementary school level. By examining mathematics curricula and textbooks, spanning from 2nd to 7th and 2007, 2009, 2015, and up to 2022 revised version, the study investigates the timing and methods of introducing these essential geometric concepts. It also explores the sequential delivery of instruction and the key focal points of pedagogy. Through the analysis of shifts in the timing and definitions, it becomes evident that these concepts of lines have predominantly been integrated as integral components of two-dimensional plane figures. This includes their role in defining the sides of polygons and the angles formed by lines. This perspective underscores the importance of providing ample opportunities for students to explore these basic geometric entities. Furthermore, the definitions of line segments, straight lines, and rays, their interrelations with points, and the relationships established between different types of lines significantly influence the development of these core concepts. Lastly, the study emphasizes the significance of introducing fundamental mathematical concepts, such as the notion of straight lines as the shortest distance in line segments and the concept of lines extending infinitely (infiniteness) in straight lines and rays. These ideas serve as foundational elements of mathematical thinking, emphasizing the necessity for students to grasp concretely these concepts through visualization and experiences in their daily surroundings. This progression aligns with a shift towards the comprehension of Euclidean geometry. This research suggests a comprehensive reassessment of how line concepts are introduced and taught, with a particular focus on connecting real-life exploratory experiences to the foundational principles of geometry, thereby enhancing the quality of mathematics education.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.2
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• pp.64-72
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• 2001

Weld line is one of serious troubles which are observed in a plastic part manufactured by a injection molding process. This is caused by many process factors, which are molding pressure, temperature, velocity, location of a injection gate, mold geometry and material properties. investigation on the effects of these process factors to the appearance of a weld line was carried out using a finite element method. Filling and packing analyses were carried out by modifying both the configuration of the injection gates and cavity thickness. Proper locations of the injection gates could be determined by considering molding pressure, temperature, velocity and frozen layer, and whereby the weld line was controled. In order to make a weak appearance of the weld line, flow velocity and flow front in a cavity were also investigated by modifying a cavity thickness. As a result, flow front was extended around the corner in the cavity by changing the flow velocity and hence the appearance of the weld line was much weakened.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.604-609
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• 2001

This numerical analysis uses the lifting surface method and frequency-domain panel method based on the linear compressible aerodynamic theory. Increased knowledge of flow conditions within mixed-flow fan should indicates means of improving performance of these turbomachines. Thus, only an approximate solution is obtained whose prime intent is to recognize the most significant characteristics of the "ideal" geometry. For a given set of operating condition, the flow conditions within mixed-flow fan depend on the geometry of the machine (three-dimensional flow effects) and on the properties of the fluid. But most treatments of the problem have been concerned with the two-dimensional flow effects for incompressible, non-viscous fluids. Interest in the field of mixed-flow fan resulted in the undertaking of a program to develop reliable design procedures that would avoid the need for lengthy development work.

• Publications of The Korean Astronomical Society
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• v.22 no.4
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• pp.89-95
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• 2007

The warm ionized medium (WIM) outside classical H II regions is a fundamental gas-phase constituent of the Milky Way and other late-type spiral galaxies, and is traced by faint emission lines at optical wavelengths. We calculate the photoionization models of the WIM in the Galaxy by a stellar UV radiation with the effective temperature 35,000 K assuming not only spherical geometry but also plane parallel geometry, and compare the results with the observed emission line ratios. We also show the dependence of the emission line ratios on various gas-phase abundances. The emergent emission-line ratios are in agreement with the average-values of observed ratios of [S II] ${\lambda}6716/H{\alpha}$, [N II] ${\lambda}6583/H{\alpha}$, [O I] ${\lambda}6300/H{\alpha}$, [O III] ${\lambda}5007/H{\alpha}$, He I ${\lambda}5876/H{\alpha}$. However, their extreme values could not be explained with the photoionization models. It is also shown that the addition of all stellar radiation from the OB stars in the Hipparcos stellar catalog resembles that of an O7-O8 type star.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.12
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• pp.801-807
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• 2016

This paper aims to compare and study the cooling performance of a battery system in accordance with the inlet and outlet geometry of the air passage in an EV. The arrangement and the heat source of the battery module were fixed, and the inlet/outlet area and its geometry were varied with the analysis of the cooling performance. The results of this study provide suggestions for the air flow stream line inside of a battery, the velocity field, and the temperature distributions. It was confirmed that the volume flow rate of air should be over $400m^3/h$, in order to satisfy conditions under $50^{\circ}C$, which is the limit condition for stable operation. It was also revealed that the diffuser outlet geometry can improve the cooling performance of battery system.

• Journal of the Korean Society for Railway
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• v.17 no.2
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• pp.106-113
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• 2014

In this study, a practical evaluation technique to detect the deterioration of railroad lines by means of train performance and track geometry measures is suggested. A train that has a specific performance and is running the straight line can make minimum travel time (ideal time). But the actual travel time will be increased by the track geometry and various speed limitations. By comparing these travel times, we can easily define the degree of line deterioration. This method does not require complex vehicle performance measures and/or specifications that exceed those of typical Train Performance Simulations (TPS). For this reason, ease of use is ensured and the results are similar to those obtained by running a TPS for practical evaluations.