• Title/Summary/Keyword: A-Light curve

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Light Curve Analyses of the Eclipsing Binaries in the Small Magellan Cloud (소마젤란 은하에 있는 식쌍성의 광도곡선 분석)

  • Kang, Young-Woon
    • Journal of Astronomy and Space Sciences
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    • v.25 no.2
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    • pp.77-86
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    • 2008
  • Large survey observations such as the EROS, the MACHO and the OGLE projects have discovered a large number of eclipsing binaries in the extra galaxies and published their light curves. The light curves of the eclipsing binaries provide fundamental stellar parameters so that accumulation of the light curves will be very useful for the research of the stellar astronomy. However it requires a lot of time to analyze the light curves. Therefore we developed new method to analyze the large number of light curves in the relatively short time period and found the photometric solution by analyzing the light curves of 20 eclipsing binaries, whose mass ratio can be determined by photometic method, in the Small Magellan Cloud.

Research on Lighting Performance Evaluation for Different Curvature Reflection Rate in Residential Space (주거공간 내 광선반 곡률 형태에 따른 채광성능평가 연구)

  • Oh, Sangwon;Lee, Heangwoo;Kim, Yongseong;Seo, Janghoo
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.27 no.6
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    • pp.328-336
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    • 2015
  • Currently, 22% of the total energy consumption of buildings in Korea is used for lighting. Light-shelves have garnered attention as a way to reduce consumption, but there are few studies on the types of curve and curvature, which limits the improvement of light-shelf performance and its design. This study constructed a test bed of actual residential types to evaluate the performance. Outcomes of light usage, according to variables of light-shelves, were used as indicators of performance evaluation. The results are as follows:1) Performance evaluation was conducted on flat-type light-shelves to verify performance of curvature-shelves, which are movable with a width of 200 mm, and the most ideal angle and specification per solar term are calculated. 2) The (-) shaped curvature contributed to a reduction in energy consumption and an improvement of evenness. 3) In case of light-shelves with (-) shaped curvature, an increased angle not exceeding $80^{\circ}$ of the arc contributed to an improvement of light penetration. 4) Appropriate specifications of curved light-shelves include movable types with widths of 200 mm, and angle ranges of $20^{\circ}{\sim}60^{\circ}$. 5) Light energy consumption of a movable light-shelf with curvature and width of 200 mm were reduced by 17% and 7.8% compared to a $0^{\circ}$ fixed and a movable light-shelf, respectively.

A PERFORMANCE IMPROVEMENT OF ANEL SCHEME THROUGH MESSAGE MAPPING AND ELLIPTIC CURVE CRYPTOGRAPHY

  • Benyamina Ahmed;Benyamina Zakarya
    • International Journal of Computer Science & Network Security
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    • v.23 no.3
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    • pp.169-176
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    • 2023
  • The vehicular ad hoc network (VANET) is currently an important approach to improve personal safety and driving comfort. ANEL is a MAC-based authentication scheme that offers all the advantages of MAC-based authentication schemes and overcomes all their limitations at the same time. In addition, the given scheme, ANEL, can achieve the security objectives such as authentication, privacy preservation, non-repudiation, etc. In addition, our scheme provides effective bio-password login, system key update, bio-password update, and other security services. Additionally, in the proposed scheme, the Trusted Authority (TA) can disclose the source driver and vehicle of each malicious message. The heavy traffic congestion increases the number of messages transmitted, some of which need to be secretly transmitted between vehicles. Therefore, ANEL requires lightweight mechanisms to overcome security challenges. To ensure security in our ANEL scheme we can use cryptographic techniques such as elliptic curve technique, session key technique, shared key technique and message authentication code technique. This article proposes a new efficient and light authentication scheme (ANEL) which consists in the protection of texts transmitted between vehicles in order not to allow a third party to know the context of the information. A detail of the mapping from text passing to elliptic curve cryptography (ECC) to the inverse mapping operation is covered in detail. Finally, an example of application of the proposed steps with an illustration

CCD PHOTOMETRY OF CONTACT BINARY WZ Cephei (접촉쌍성 WZ Cephei의 CCD 측광관측)

  • Lee, Woo-Baik;Kang, Young-Woon;Oh, Kyu-Dong
    • Journal of Astronomy and Space Sciences
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    • v.25 no.1
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    • pp.19-24
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    • 2008
  • We present the full BVR light curves and five times of minima of WZ Cep to provides a complete photometric solution and to confirm the long term variation of the light curves. Our light curves show symmetry while previous light curves of Hoffmann (1984) show a high degree of asymmetry (the O'Connell effect). The BVR light curves were analyzed by the method of Wilson-Devinney Differential Correction. Our photometric results show a good agreement with those of Djurasevic et al. (1998).

A Study on Gender Expressed in Contemporary Fashion (현대 패션에 표현된 젠더(Gender)에 관한 연구)

  • Park, Mi-Ryung
    • Fashion & Textile Research Journal
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    • v.5 no.4
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    • pp.324-330
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    • 2003
  • The purpose of this study is on the meaning and variety about gender expressed in modern fashion. The results are as follows ; First, the typical masculine gender was authority, discretion as a result of heteropatriarchy focused on the western reason. It was conservative and the symbolic image type of the meaning excluded masculine sexual expression. Dress and its ornament was expressed as the style of straight silhouette, dark color, rough and stiff material. Second, the typical feminine gender was the symbolic image type of a mother and a wife defined relatively by man as a result of western heteropatriarchy and the image type which men regarded women as sexual objects. Dress and its ornament was expressed as the style of silhouette which let bodily curve out, light color, soft material. The most typical item is dress and suit. Third, androgyny has been described as the feminie gender of androgynous, which shows masculine image as the effect of feminism and social success of professional women. Dress and its ornament is expressed as the style of business suit, the symple of typical man's one. The masculine gender of androgynous is showed man's suit as silhouette that let bodily curve out, light color, exposure and soft material, which is the symbol of feminine dress, Fourth, unisex is the area of dress and its ornament used the sexless symbol which there has been no gender more because of the spread of sports and diffusion of leisure in life style.

AT2018cow : Photometric Analysis of Fast-evolving, Luminous and Bluish Transient

  • Paek, Gregory SungHak;Im, Myungshin;Choi, Changsu;Lim, Gu;Kim, Sophia;Paek, Insu;Hwang, Sungyong;Kim, Taewoo
    • The Bulletin of The Korean Astronomical Society
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    • v.43 no.2
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    • pp.53.3-54
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    • 2018
  • On June 16 AT2018cow (ATLAS 18qqn) was discovered as a bright and fast-evolving transient in nearby universe z ~ 0.01. It brightened by more than 4 mag within a day, and its light curve was decayed rapidly and has a high luminous peak which is more luminous than most of core-collapse supernova. It also overall showed a blue color in an unprecedented case of transients. There have been attempts to explain this behavior with existing models, but most of them have been insufficient except for one - tidal disruption by intermediate-mass black hole. We began to monitor this transient from about 4 days after the discovery until August 21 in the optical bands with 1m-class telescopes over the world. Here, we present a light curve of AT2018cow in the B, V, R and I bands, and analyze its photometric properties and compare to other transients and models.

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New Light Curves and Orbital Period Investigations of the Interacting Binary System UV Piscium

  • Jeong, Min-Ji;Han, Wonyong;Kim, Chun-Hwey;Yoon, Joh-Na;Kim, Hyoun-Woo
    • Journal of Astronomy and Space Sciences
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    • v.36 no.2
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    • pp.75-86
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    • 2019
  • UV Psc is a typical RS CVn type system undergoing dynamic chromosphere activity. We performed photometric observations of the system in 2015 and secured new BVR light curves showing well-defined photometric waves. In this paper, we analyzed the light curves using Wilson-Devinney binary code and investigated the orbital period of the system. The combination of our light curve synthesis with the spectroscopic solution developed by previous investigators yielded the absolute parameters as: $M_1=1.104{\pm}0.042M_{\odot}$, $R_1=1.165{\pm}0.025R_{\odot}$, and $L_1=1.361{\pm} 0.041L_{\odot}$ for the primary star, and $M_2=0.809{\pm}0.082M_{\odot}$, $R_2=0.858{\pm}0.018R_{\odot}$, and $L_2=0.339 {\pm}0.010L_{\odot}$ for the secondary star. The eclipse timing diagram for accurate CCD and photoelectric timings showed that the orbital period may vary either in a downward parabolic manner or a quasi-sinusoidal pattern. If the latter is adopted as a probable pattern for the period change, a more plausible account for the cyclic variation may be the light time effect caused by a circumbinary object rather than an Applegate-mechanism occurring via variable surface magnetic field strengths.

Physical parameters of the detached eclipsing binary KIC3858884

  • Lee, Chung-Uk;Kim, Seung-Lee;Lee, Jae-Woo
    • The Bulletin of The Korean Astronomical Society
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    • v.36 no.2
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    • pp.141.2-141.2
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    • 2011
  • We present physical parameters of the detached eclipsing binary KIC3858884, which has a d-Scuti type pulsating secondary component. To derive orbital elements from radial-velocity curve, high-resolution Echelle spectra were obtained at the Bohyunsan Optical Astronomy Observatory in Korea. The BOES spectra and Kepler photometric data were analyzed with JKTEBOP and Wilson-Devinney model for eclipsing light-curve synthesis and Period04 for pulsation frequency analysis. After the iterative curve fitting, we determined physical parameters of KIC3858884 as $M_1=2.02{\pm}0.23M_{\odot}$, $M_2=2.02{\pm}0.16M_{\odot}$, $R_1=3.61{\pm}0.12R_{\odot}$, $R_2=2.84{\pm}0.10R_{\odot}$, respectively.

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SYBR Green I-based Real-time PCR Assay and Melting Curve Analysis for Rapid Detection of Staphylococcus aureus from Raw Milks Samples (Real-time PCR을 이용한 원유시료 유래 황색포도상구균의 신속 검출)

  • Jung, Jae-Hyuk;Jeong, Soon-Young;Lee, Sang-Jin;Choi, Sung-Sook
    • Journal of Food Hygiene and Safety
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    • v.23 no.2
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    • pp.121-128
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    • 2008
  • The aim of this study was to develop a LightCycler-based real time PCR (LC-PCR) assay and to evaluate its diagnostic use for the detection of Staphylococcus aureus in raw milk samples. Following amplification of 113 bp of coa gene encoding an coagulase precursor specific for Staphylococcus aureus, melting curve and DNA sequencing analysis was performed to verify the specificity of the PCR products. Amplification of 209 bp gene encoding an altered penicillin-binding protein, PBP2a (mecA), melting curve analysis and DNA sequencing analysis was performed to verify methicillin resistance Staphylococcus aureus (MRSA). According to this study, 6 of 647 raw milk samples showed S. aureus positive and 2 of them showed a mecA positive and the detection limit was 10 fg of DNA. And we also isolated Staphylococcus chromogenes a causative agent of exudative epidermitis in pigs and cattle from 3 samples.

Optical Sensitivity of TL Glow Peaks Separated Using Computerized Glow Curve Deconvolution for RTL Quartz

  • Kim, Myung-Jin;Kim, Ki-Bum;Hong, Duk-Geun
    • Journal of Radiation Protection and Research
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    • v.43 no.3
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    • pp.114-119
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    • 2018
  • Background: The retrospective dosimetry using RTL quartz can be improved by information for an optical sensitivity of sample connected with the equivalent dose determination. Materials and Methods: The quartz sample from a volcanic rock of Japan was used. After correcting the thermal quenching effect, RTL peaks of quartz were separated by the CGCD method cooperated with the general order kinetics. The number of overlapped glow peaks were ascertained by the $T_m-T_{stop}$ method. The optical sensitivity was examined by comparing the change of intensity on RTL glow peaks measured after exposure to light from a solar simulator with various illumination times. Results and Discussion: Seven glow peaks appeared to be overlapped on the RTL glow curve. The general order kinetics model was appropriate to separate glow peaks. After exposure to light from a solar simulator from a few minutes to 416 hr, the signals for peaks P4 and P5 decayed following the form of $f(t)=a_1e^{-{\lambda}1t}$, while the signals for peaks P6 and P7 decayed by the form of $f(t) = a_1e^{-{\lambda}1t}+a_2e^{-{\lambda}2t}+a_3e^{-{\lambda}3t}$. Conclusion: For dosimetric peaks, the times taken to reduce the RTL signal to half of its initial value were 70 sec for the peak P4, 54 s for the peak P5, 9,840 sec for the peak P6 and 26,580 sec for the peak P7, respectively. We conclude that the optical sensitivity of peaks P4, and P5 gives much higher than that of peaks P6 and P7.