• 천문학회보
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• 제46권2호
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• pp.40.3-41
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• 2021

Minor mergers leave behind long lived, but extremely faint and extended tidal features including tails, streams, loops and plumes. These act as a fossil record for the host galaxy's past interactions, allowing us to infer recent accretion histories and place constraints on the properties and nature of a galaxy's dark matter halo. However, shallow imaging or small homogeneous samples of past surveys have resulted in weak observational constraints on the role of galaxy mergers and interactions in galaxy assembly. The Rubin Observatory, which is optimised to deliver fast, wide field-of-view imaging, will enable deep and unbiased observations over the 18,000 square degrees of the Legacy Survey of Space and Time (LSST), resulting in samples of potentially of millions of objects undergoing tidal interactions. Using realistic mock images produced with state-of-the-art cosmological simulations we perform a comprehensive theoretical investigation of the extended diffuse light around galaxies and galaxy groups down to low stellar mass densities. We consider the nature, frequency and visibility of tidal features and debris across a range of environments and stellar masses as well as their reliability as an indicator of galaxy accretion histories. We consider how observational biases such as projection effects, the point-spread-function and survey depth may effect the proper characterisation and measurement of tidal features, finding that LSST will be capable of recovering much of the flux found in the outskirts of L* galaxies at redshifts beyond local volume. In our simulated sample, tidal features are ubiquitous In L* galaxies and remain common even at significantly lower masses (M*>10^10 Msun). The fraction of stellar mass found in tidal features increases towards higher masses, rising to 5-10% for the most massive objects in our sample (M*~10^11.5 Msun). Such objects frequently exhibit many distinct tidal features often with complex morphologies, becoming increasingly numerous with increased depth. The interpretation and characterisation of such features can vary significantly with orientation and imaging depth. Our findings demonstrate the importance of accounting for the biases that arise from projection effects and surface-brightness limits and suggest that, even after the LSST is complete, much of the discovery space in low surface-brightness Universe will remain to be explored.

• 천문학회지
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• 제35권1호
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• pp.41-57
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• 2002

We have written a code called QDM_sca, which numerically solves the problem of radiative transfer in an anisotropically scattering, spherical atmosphere. First we formulate the problem as a second order differential equation of a quasi-diffusion type. We then apply a three-point finite differencing to the resulting differential equation and transform it to a tri-diagonal system of simultaneous linear equations. After boundary conditions are implemented in the tri-diagonal system, the QDM_sca radiative code fixes the field of specific intensity at every point in the atmosphere. As an application example, we used the code to calculate the brightness of atmospheric diffuse light(ADL) as a function of zenith distance, which plays a pivotal role in reducing the zodiacal light brightness from night sky observations. On the basis of this ADL calculation, frequent uses of effective extinction optical depth have been fully justified in correcting the atmospheric extinction for such extended sources as zodiacal light, integrated starlight and diffuse galactic light. The code will be available on request.

• 한국위성정보통신학회논문지
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• 제9권1호
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• pp.70-73
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• 2014

최근 휴대용 정보전자기기의 비약적인 사용의 증가는 충격에 보다 강한 디스플레이에 대한 연구를 발전시키는 계기가 되었다. 일부 제조회사에서 AMOLED를 사용한 디스플레이에서 유연한 특성을 가진 제품을 선보이고 있으나, 그 사용량에 있어서 압도적으로 많은 부분을 차지하고 있는 것은 LCD 이다. 특히 LCD는 구조적인 문제로 인하여 반드시 후면광원을 사용하여야 하는데, 면발광형식의 조광장치를 얇은 두께로 구현하는데 사용되는 것이 아크릴 재질의 도광판이다. 본 연구에서는 유연하지 않은 메틸메타아크릴레이트에 부틸 아크릴레이트 고무계열의 합성재료를 첨가하여 유연성을 유지하고, 투과율을 90%까지 상승시킨 KURARITY 라는 재질을 사용한 패턴의 설계 및 성형 결과를 통해서 유연한 후면광원의 가능성을 평가하는데 주력하였다. 평가 결과 기존의 광원과 동일한 수준의 밝기 및 휘도 균일도를 얻을 수 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.9-9
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• 2010

In this paper, High Brightness LED driver IC using new current sensing circuit is proposed. This LED driver IC can provide a constant current with high current precision over a wide input voltage range. The proposed current-sensing circuit is composed of a cascode current sensor and a current comparator with only one reference voltage. This IC minimizes the voltage stress of the MOSFET from the maximum input voltage and has low power consumption and chip area by using simple-structured comparator and minimum bias current. The LED current ripple of the designed IC is in ${\pm}5%$ and a tolerance of the average LED current is lower than 2.43%. This shows much improved feature than the previous method. Also, protections for input voltage and operating temperature are designed to improve the reliability of the designed IC. Designed LED driver IC uses $1{\mu}m$ X-Fab. BiCMOS process parameters and electrical characteristics and functioning are verified by spectre(Cadence) simulation.

• 한국태양에너지학회 논문집
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• 제34권4호
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• pp.91-99
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• 2014

The purpose of the study is to apprehend the preference of occupants to colors and installation locations for DSC combined windows and doors, and suggest a concept to optimize the design and function of windows and doors. A miniature model was made applying green, blue, and red colored DSC windows and doors to survey preference about DSC colors and applied location. And a survey was accomplished to 140 subjects by showing pictures of the model and the result of the survey became the basis for suggesting a concept to design DSC integrated windows and doors. Through the survey, blue color and upper part were chosen as the highest level of satisfaction in the situation of external brightness and residence. On the contrary to this, red color was chosen as the lowest level of preference when applied to both of upper and lower parts of winders and doors. Therefore, it's expected that, if various patterns of texture are developed for blue colored DSC, and installation is arranged based on upper part of windows and doors where lighting condition and comfort are less affected, then, conditions of brightness, view, and residents satisfaction will be equally fulfilled.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권3호
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• pp.1043-1064
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• 2020

A kind of Subjective Imaging Effect Assessment (SIEA) method and its applications on intelligent imaging terminal design in engineering site are presented. First, some visual assessment indices are used to characterize the imaging effect: the image brightness, the image brightness uniformity, the color image contrast, the image edge blur, the image color difference, the image saturation, the image noise, and the integrated imaging effect index. A linear weighted function is employed to carry out the SIEA computation and the Analytic Hierarchy Process (AHP) technique is used to estimate its weights. Second, a SIEA software is developed. It can play images after the settings of assessment index or assessment reaction time, etc. Third, two cases are used to illustrate the application effects of proposed method: the image enhancement system design for surveillance camera and the imaging environment perception system design for intelligent lighting terminal. A Prior Sequential Stimulus (PSS) experiment is proposed to improve the evaluation stability of SIEA method. Many experiment results have shown the proposed method can realize a stable system design or parameters setting for the intelligent imaging terminal in engineering site.

• 한국의류학회지
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• 제21권8호
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• pp.1287-1296
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• 1997

The purpose of the study is to make experimental whether three-dimensional body (especially face) has illusion based on theoretical background of form dimensions and color bright among precedent multi-form illusion, using the function of computer simulation. To investigate illusion that factors of clothing design(line, color, material) effect face, as the following is tried to solve giving change to neckline, collar, scarf which is believed to influence near face. How to make experiment as follows watching in order 13 scenes of a pair of with basic design and experiment design. Then the data were subjected to analysis of variance and Duncan's multiple range test. The result of this studying as follows, 1. Face looks larger in complex neckline than simple neckline. The larger collar is the larger face looks. 2. In white jacket, illusion(the lower luminosity of scarf color gets, the brighter face brightness gets) is shown. In black jacket, also illusion(the higher luminosity of scarf color gets, the darker face brightness gets) is shown. 3. In experiment on hardness and softness of face impression according to the material of collar, collar of knit and fur gives us assimilation illusion bring softer impression of face.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2013년도 추계학술대회
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• pp.188-191
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• 2013

본 논문은 수직형 정수처리시설 내의 에너지 절감을 위해 외부의 자연광과 인체감지를 통한 실내 조도 제어용 LED 조명 제어보드를 구성하여 무선 환경에서의 실시간 모니터링을 통해 조명 제어가 가능하도록 구성하였다. 또한, Zigbee 통신을 LED 조명에 적용함으로서 무선 데이터 전송과 능동적 LED 조명 밝기제어가 가능하도록 구성하였다. 제안한 제어방식은 외부의 자연광에 따라 조명의 밝기를 단계별로 디밍 제어하여 조절 및 제어함으로써 실내에너지를 실시간으로 제어하여 에너지 절약 효과를 극대화할 수 있다.

• 천문학회보
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• 제37권2호
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• pp.106.1-106.1
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• 2012

The Gegenschein is a faint glow around the anti-solar point caused by the interplanetary dust particle(IDP)'s back-scattering enhancement. From the previous low resolution observations, the overall morphology of the Gegenschein has been intensively studied. However, sub-degree scale fine structure of the Gegenschein is still not well known, even though the detailed morphology of the Gegenschein within a few degree from the anti-solar point may supply pivotal information about the property of the IDPs. We made optical CCD observations of the Gegenschein between 2003 March and 2006 November. From the observations, we succeeded in making high resolution images of the Gegenschein, with unprecedented 1.'4 resolution. Our results concur with IDP cloud model based on the infrared observations combined with scattering phase function derived from low resolution data. The only exception is the anti-solar point. We found a steep additional brightness enhancement existing at the exact anti-solar point. Plausible explanation of the finding is that the IDPs are significantly larger than observing wavelength, and have irregular morphology or inhomogeneous internal structure. Furthermore, we measured average geometric albedo of the IDPs from the optical brightness of the anti-solar point. The geometric albedo was $0.06{\pm}0.01$, similar to those of comets or C-type asteroids.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.604-609
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• 2002

The passive microwave remote sensing has progressed considerably in recent years. Important earth surface parameters are detected and monitored by airborne and space born radiometers. However the spatial resolution of real aperture measurements is constrained by the antenna aperture size available on orbiting platforms and on the ground. The inverse problem technique is researched in order to improve the spatial resolution of microwave scanning radiometer. We solve a two-dimensional (surface) temperature-imaging problem with a major intention to develop high-resolution methods. In this paper, the scenario for estimation of both radiometer point spread function (PSF) and target configuration is explained. The PSF of the radiometer is assumed to be unknown and estimated from the observations. The configuration and brightness temperature of targets are also estimated. To do this, we deal with the parametric modeling of observation scenario. The performance of developed algorithms is illustrated on two-dimensional experimental data obtained by the water vapor radiometer.