• Title/Summary/Keyword: Solar Activity

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The Study on Activity Star Problem and Optimum Construction Method Through the Defect Case of Zero Energy House in the Existing Building (기축건물의 제로에너지 하우스 하자 사례를 통한 공종별 문제점 및 최적구축 방안에 관한 연구)

  • Kim, Sun-Geun;Kwon, Soon-Wook
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.28 no.4
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    • pp.262-270
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    • 2015
  • In this paper existing buildings, not a new buildings and house for living people not just a displaying and a viewing, created by the imagine effect or virtual simulation was applied various Active and Passive elements. After constructing zero-energy houses, through default case happened during operation period it is described problems and solutions about field part, work classification, installation by Location part, and Installation equipment part. Since then, to take advantage of this thesis, it's the purpose of this paper using as the baseline data for building a zero-energy house in another similar case.

Numerical Study on Human Thermal Comfort in a Passenger Train (기차 승객의 온열 쾌적성에 관한 수치해석)

  • Kim, Man-Hoe
    • Transactions of the Korean Society of Automotive Engineers
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    • v.24 no.1
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    • pp.82-89
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    • 2016
  • This paper presents computational fluid dynamics (CFD) analysis on passenger thermal comfort in a train. Human thermal comfort in vehicles depends mainly on air temperature, mean radiant temperature, air velocity, humidity, and direct solar flux, as well as the level of activity and thermal properties of clothing and seat. The velocity and temperature distribution in a train with and without passengers are reported. The thermal comfort in a passenger train are also presented based on PMV and PPD indices with 16 segments of the human body.

Object Tracking Based on Weighted Local Sub-space Reconstruction Error

  • Zeng, Xianyou;Xu, Long;Hu, Shaohai;Zhao, Ruizhen;Feng, Wanli
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.2
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    • pp.871-891
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    • 2019
  • Visual tracking is a challenging task that needs learning an effective model to handle the changes of target appearance caused by factors such as pose variation, illumination change, occlusion and motion blur. In this paper, a novel tracking algorithm based on weighted local sub-space reconstruction error is presented. First, accounting for the appearance changes in the tracking process, a generative weight calculation method based on structural reconstruction error is proposed. Furthermore, a template update scheme of occlusion-aware is introduced, in which we reconstruct a new template instead of simply exploiting the best observation for template update. The effectiveness and feasibility of the proposed algorithm are verified by comparing it with some state-of-the-art algorithms quantitatively and qualitatively.

QZSS TEC Estimation and Validation Over South Korea

  • Byung-Kyu Choi;Dong-Hyo Sohn;Junseok Hong;Woo Kyoung Lee
    • Journal of Positioning, Navigation, and Timing
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    • v.12 no.4
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    • pp.343-348
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    • 2023
  • The ionosphere acts as the largest error source in the Global Navigation Satellite System (GNSS) signal transmission. Ionospheric total electron content (TEC) is also easily affected by changes in the space environment, such as solar activity and geomagnetic storms. In this study, we analyze changes in the regional ionosphere using the Qusai-Zenith Satellite System (QZSS), a regional satellite navigation system. Observations from 9 GNSS stations in South Korea are used for estimating the QZSS TEC. In addition, the performance of QZSS TEC is analyzed with observations from day of year (DOY) 199 to 206, 2023. To verify the performance of our results, we compare the estimated QZSS TEC and CODE Global Ionosphere Map (GIM) at the same location. Our results are in good agreement with the GIM product provided by the CODE over this period, with an averaged difference of approximately 0.1 TECU and a root mean square (RMS) value of 2.89 TECU.

Synthesis and Photodecomposition of N-Doped $TiO_2$ Surface Treated by Ammonia (암모니아 표면처리 된 질소 도핑 $TiO_2$ 광촉매의 합성 및 광분해반응)

  • Kim, Yesol;Bai, Byong Chol;Lee, Young-Seak
    • Applied Chemistry for Engineering
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    • v.23 no.3
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    • pp.308-312
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    • 2012
  • Nitrogen doped $TiO_2$ photocatalysts were prepared by ammonia for exploring the visible light photocatalytic activity. To explore the visible light photocatalytic activity of the nitrogen doped $TiO_2$ photocatalyst, the removal of methylene blue dye was investigated under the sunlight. SEM images showed that the flocculated particle sizes of N-doped $TiO_2$ decreased due to the reaction with ammonia. XRD patterns demonstrated that the samples calcined at temperatures up to $600^{\circ}C$ and doped with nitrogen using ammonia clearly showed rutile as well as anatase peaks. The XPS results showed that the nitrogen composition onto $TiO_2$ increased according to the reaction time with ammonia. Photocatalytic activity of the nitrogen doped $TiO_2$ was better than that of undoped $TiO_2$. Nitrogen doping onto the $TiO_2$ also affected the crystal type of $TiO_2$ photocatalyst.

Effects of Chronic Chitosan Salt Supplementation on Blood Pressure, Plasma Component, and Lipid Profile in Healthy Male and Female Adults

  • Kim, Hag-Lyeol;Son, Yeon-Hee;Kim, Seon-Jae;Kim, Du-Woon;Ma, Seung-Jin;Cho, Geon-Sik;Kim, In-Cheol;Ham, Kyung-Sik
    • Food Science and Biotechnology
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    • v.16 no.2
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    • pp.249-254
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    • 2007
  • The effects of chronic chitosan salt supplementation on the systolic (SBP) and diastolic blood pressure (DBP), and physiological parameters were investigated in healthy male and female adult. Chitosan salt was conducted by measuring various health-related factors such as body composition, plasma $Na^+$, $Cl^-$, lipid, and lipoproteins profiles, glutamic oxaloacetic transaminase (GOT), and glutamic pyruvic transaminase (GPT) activity. Chitosan salt supplementation no significant differences before and after supplement in body composition variables and in SBP and DBP in either male or female. Plasma sodium and chlorine concentration no significant changes during chitosan salt supplementation, and no significant difference between two genders. Plasma GOT and GPT activity no different before and after supplement in either male or female. GOT activity significantly higher for male before supplement (p<0.05), and 2 weeks after supplement (p<0.01). The lipid and lipoproteins profiles of plasma no significant changes during chitosan salt supplementation in either male or female subjects. In summary, the chronic intake of chitosan salt did not affect the SBP or DBP, and posed no health risks.

Seasonal and Latitudinal Variations of the F2-Layer during Magnetic Storms

  • Park, Yoon-Kyung;Kwak, Young-Sil;Ahn, Byung-Ho
    • Journal of Astronomy and Space Sciences
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    • v.30 no.4
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    • pp.231-239
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    • 2013
  • To identify seasonal and latitudinal variations of F2 layer during magnetic storm, we examine the change of daily averages of foF2 observed at Kokubunji and Hobart during high (2000~2002) and low (2006~2008) solar activity intervals. It is found that geomagnetic activity has a different effect on the ionospheric F2-layer electron density variation for different seasons and different latitudes. We, thus, investigate how the change of geomagnetic activity affects the ionospheric F2-layer electron density with season and latitude. For this purpose, two magnetic storms occurred in equinox (31 March 2001) and solstice (20 November 2003) seasons are selected. Then we investigate foF2, which are observed at Kokubunji, Townsville, Brisbane, Canberra and Hobart, Dst index, Ap index, and AE index for the two magnetic storm periods. These observatories have similar geomagnetic longitude, but have different latitude. Furthermore, we investigate the relation between the foF2 and the [O]/[$N_2$] ratio and TEC variations during 19-22 November 2003 magnetic storm period. As a result, we find that the latitudinal variations of [O]/[$N_2$] ratio and TEC are closely related with the latitudinal variation of foF2. Therefore, we conclude that the seasonal and latitudinal variations of foF2 during magnetic storm are caused by the seasonal and latitudinal variations of mean meridional circulation of the thermosphere, particularly upwelling and downwelling of neutral atmosphere during magnetic storm.

Synthesis of functional ZnO nanoparticles and their photocatalytic properties

  • Nam, Sang-Hun;Kim, Myoung-Hwa;Lee, Sang-Duck;Kim, Min-Hee;Boo, Jin-Hyo
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.02a
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    • pp.54-54
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    • 2010
  • Zinc oxide is metal oxide semiconductor with the 3.37 eV bandgap energy. Zinc oxide is very attractive materials for many application fields. Zinc Oxide has many advantages such as high conductivity and good transmittance in visible region. Also it is cheaper than other semiconductor materials such as indium tin oxide (ITO). Therefore, ZnO is alternative material for ITO. ZnO is attracting attention for its application to transparent conductive oxide (TCO) films, surface acoustic wave (SAW), films bulk acoustic resonator (FBAR), piezoelectric materials, gas-sensing, solar cells and photocatalyst. In this study, we synthesized ZnO nanoparticles and defined their physical and chemical properties. Also we studied about the application of ZnO nanoparticles as a photocatalyst and try to find a enhancement photocatalytic activity of ZnO nanorticles.. We synthesized ZnO nanoparticles using spray-pyrolysis method and defined the physical and optical properties of ZnO nanoparticles in experiment I. When the ZnO are exposed to UV light, reduction and oxidation(REDOX) reaction will occur on the ZnO surface and generate ${O_2}^-$ and OH radicals. These powerful oxidizing agents are proven to be effective in decomposition of the harmful organic materials and convert them into $CO_2$ and $H_2O$. Therefore, we investigated that the photocatalytic activity was increased through the surface modification of synthesized ZnO nanoparticles. In experiment II, we studied on the stability of ZnO nanoparticles in water. It is well known that ZnO is unstable in water in comparison with $TiO_2$. $Zn(OH)_2$ was formed at the ZnO surface and ZnO become inactive as a photocatalyst when ZnO is present in the solution. Therefore, we prepared synthesized ZnO nanoparticles that were immersed in the water and dried in the oven. After that, we measured photocatalytic activities of prepared samples and find the cause of their photocatalytic activity changes.

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Eco-friendly Smart Outdoor Jacket Production and Usability Evaluation (환경 친화적 스마트 아웃도어 재킷제작 및 사용성 평가)

  • Lee, Jeong Ran
    • Journal of the Korean Society of Clothing and Textiles
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    • v.38 no.6
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    • pp.845-856
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    • 2014
  • This study focused on the production and usability evaluation of smart outdoor jackets that are designed to provide convenience to middle-aged people by embedding devices for lighting and location tracing. The results were as follows. 1. Jacket power supplier was a assembled system composed of battery, charger, controller and switch. A solar cell was attached on the upper arm, and a wire type EL on the center line of a raglan sleeve along with a GPS on the left sleeve with a transparent vinyl pocket. The total weight of the jacket embedded with devices was 385-520g. 2. Operation of function, activity, acceptability, safety, convenience for device use, appearance, practical maintenance were selected based on an analysis of evaluation criteria of previous smart wear research. Criteria were narrowed to three major categories of satisfaction, appearance and maintenance. 3. Use satisfaction criterion consisted of wearable device functionality and physical, psychological use convenience. The evaluation indicated actual functionality. EL functions were especially effective and necessary. Convenience of use showed that a smart jacket was thought to be safe and the size was moderate regardless of age and gender. Outer appearance was satisfactory and respondents praised the color. The practical maintenance evaluation indicated that there was no challenge in doing the laundry since the solar battery and GPS were detachable. The practical use of smart outdoor jackets confirmed by fabric that was washable and dried quickly.

MODIFIED CONVOLUTIONAL NEURAL NETWORK WITH TRANSFER LEARNING FOR SOLAR FLARE PREDICTION

  • Zheng, Yanfang;Li, Xuebao;Wang, Xinshuo;Zhou, Ta
    • Journal of The Korean Astronomical Society
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    • v.52 no.6
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    • pp.217-225
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    • 2019
  • We apply a modified Convolutional Neural Network (CNN) model in conjunction with transfer learning to predict whether an active region (AR) would produce a ≥C-class or ≥M-class flare within the next 24 hours. We collect line-of-sight magnetogram samples of ARs provided by the SHARP from May 2010 to September 2018, which is a new data product from the HMI onboard the SDO. Based on these AR samples, we adopt the approach of shuffle-and-split cross-validation (CV) to build a database that includes 10 separate data sets. Each of the 10 data sets is segregated by NOAA AR number into a training and a testing data set. After training, validating, and testing our model, we compare the results with previous studies using predictive performance metrics, with a focus on the true skill statistic (TSS). The main results from this study are summarized as follows. First, to the best of our knowledge, this is the first time that the CNN model with transfer learning is used in solar physics to make binary class predictions for both ≥C-class and ≥M-class flares, without manually engineered features extracted from the observational data. Second, our model achieves relatively high scores of TSS = 0.640±0.075 and TSS = 0.526±0.052 for ≥M-class prediction and ≥C-class prediction, respectively, which is comparable to that of previous models. Third, our model also obtains quite good scores in five other metrics for both ≥C-class and ≥M-class flare prediction. Our results demonstrate that our modified CNN model with transfer learning is an effective method for flare forecasting with reasonable prediction performance.