• Journal of Digital Convergence
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• v.17 no.6
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• pp.211-217
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• 2019

This study suggested the alternatives for improving consumers' engagement with digital signage (DS) by analyzing the researches of the effectiveness of DS in marketing and public areas, which is recognized as an essential communication tool for commercial or public matters. According to the results, affective DS ad content of DS resulted in positive shoppers' buying behaviors and perceiving buying environment; DS was also effective for public affairs, which how proper channel and message for the target public resulted in solving community problems. However, it was rare to measure precisely the level of consumers' engagement with DS content and what DS content aroused higher engagement in both areas. Thus, DS content should be more customized based on multiple converged contents for consumers' engagement and the research efforts of DS should be focused on the development of not only its device technology, but also creative content.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.39.1-39.1
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• 2018

We present our observational attempts to precisely measure the central mass of a proto-brown dwarf candidate, L328-IRS, in order to investigate whether L328-IRS is in the substellar mass regime. Observations were made for the central region of L328-IRS with the dust continuum and CO isotopologue line emission at ALMA band 6, discovering the detailed outflow activities and a deconvolved disk structure of a size of ${\sim}87AU{\times}{\sim}37AU$. We investigated the rotational velocities as a function of the disk radius, finding that its motions between 130 AU and 60 AU are partially fitted with a Keplerian orbit by a stellar object of ${\sim}0.30M_{\odot}$, while the motions within 60 AU do not follow any Keplerian orbit at all. This makes it difficult to lead a reliable estimation of the mass of L328-IRS. Nonetheless, our ALMA observations were useful enough to well constrain the inclination angle of the outflow cavity of L328-IRS as ${\sim}66^{\circ}$ degree, enabling us to better determine the mass accretion rate of ${\sim}8.9{\times}10^{-7}M_{\odot}yr-1$.From assumptions that the internal luminosity of L328-IRS is mostly due to this mass accretion process in the disk, or that L328-IRS has mostly accumulated the mass through this constant accretion rate during its outflow activity, its mass was estimated to be ${\sim}0.012-0.023M_{\odot}$, suggesting L328-IRS to be a substellar object. However, we leave our identification of L328-IRS as a proto-brown dwarf to be tentative because of various uncertainties especially regarding the mass accretion rate.

• International Area Studies Review
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• v.21 no.4
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• pp.65-83
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• 2017

As Global value chain(GVC) is deepening, the importance of intermediated good trade is growing in international trade issues. Such facts lead to much discussions about the relation between Global Outsourcing and pollution. This study analyzed the effect of Global outsourcing on Environment using the data including 21 industries for 2004-14. $CO_2$ intensity is used as a proxy for the environment variable and to measure Global outsourcing and I employed the method suggested by Feenstra and Hanson(1999), Amiti and Wei(2006). To examine the effect Global outsourcing on the Environment more precisely, this paper controlled the factors that can affect the environment level on the basis of the theory suggested by Copeland and Taylor(1994). In the methodology, System GMM is employed to solve endogenous problem. The results show that for overall industries, Global outsourcing effect cannot be identified and for polluting industries, the result is identical. However, Global outsourcing has a negative effect on the pollution level for China and developing countries. In other words, as Global outsourcing is increasing, the national pollution level is decreasing.

• Journal of the Korean Society of Safety
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• v.35 no.6
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• pp.78-84
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• 2020

The F&EI technique is one of the risk assessments with many advantages. It can save time and effort compared to quantitative risk assessment (QRA). By using the evaluation result of this technique, it is possible to check the effectiveness of the investment cost. In addition, a relative risk ranking can be created and used to establish the facility management cycle and to prioritize investment. However, evaluating the target process can be evaluated more than the actual risk since the LCCF, a loss prevention measure, is too limited. In addition, calculating premiums via this method can result in excessive premiums, making it difficult to evaluate the risk precisely. Therefore, new safety guard was added to the LCCF of the F&EI risk assessment with reference to HAZOP and LOPA techniques. Newly added LCCFs are Deflagration arrester, Check valve, SIS, and Vacuum beaker, etc. As a case study, F&EI risk assessment was performed on Acetone storage tank of a API (Active pharmaceutical ingredient) plant to compare actual MPPD. The estimated loss amount was 592,558$ for the existing technique and 563,571$ for the improved technique, which was reduced by about 5% compared to the previous one.This proved that a more precise evaluation is possible and that the efforts for safety at the workplace are reflected in the evaluation results.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.52.1-52.1
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• 2021

We present the results of multi-epoch, multi-frequency monitoring of a blazar 4C +29.45, which was regularly monitored as part of the Interferometric Monitoring of GAmma-ray Bright AGNs program - a key science program of the Korean Very long baseline interferometry Network (KVN). Observations were conducted simultaneously at 22, 43, 86 and 129 GHz during the 4 years from December 2012 to December 2016. We also used additional data from the 15 GHz Owens Valley Radio Observatory (OVRO) monitoring program. From the 15 GHz light curve, we estimated the variability time scales of the source during several radio flux enhancements. We found that the source experiencesd 6 radio flux enhancements with variability time scales of 9-187 days during the observing period, yielding corresponding variability Doppler factors of 9-27. From the multi-frequency simultaneous KVN observations, we were able to obtain accurate radio spectra of the source and hence to more precisely measure the turnover frequencies 𝜈_r of synchrotron self-absorbed (SSA) emission with a mean value of ${\bar{\nu}_r}=28.9GHz$. Using jet geometry assumptions, we estimated the size of the emitting region at the turnover frequency. Taking into account these results, we found that the equipartition magnetic field strength is up to two orders of magnitudes higher than the SSA magnetic field strength (0.6-99 mG). This is consistent with the source being particle dominated.

• Journal of the Institute of Convergence Signal Processing
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• v.24 no.1
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• pp.15-20
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• 2023

In general, maintaining an incorrect sitting posture for a long time is widely known to adversely affect the spine. Recently, several researchers have been interested in the causal relationship between incorrect sitting posture and spinal diseases, and have been studying methods to precisely measure changes in sitting or standing posture to prevent spinal diseases. In previous studies, we have developed a sensor device capable of measuring real-time posture change, applied a momentum calculation algorithm to improve the accuracy of real-time posture change measurement, and verified the accuracy of the postural change measurement sensor. In this study, we developed a posture measurement and analysis device that considers changes in the center of body pressure through the developed sitting pressure measurement, and it confirmed the sensor as an auxiliary tool to increase the accuracy of posture correction training with improving the user's visual feedback.

• Journal of The Korean Association For Science Education
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• v.26 no.7
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• pp.826-834
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• 2006

The purpose of this study is to examine the pre-service teachers' concept of measurement uncertainty. The subject of this study were 27 pre-service middle-school teachers in Seoul. They carried out open-ended inquiry tasks and surveyed two kinds of open questionnaires, and interviewed several persons. We analysed their behavior and responses. Through the analysis, we summarize pre-service teachers' concept about measurement uncertainty with representation data, precision and accuracy, error analysis, propagation of uncertainty. The results show that the teachers' concept is different from scientists' concept. They make a mistake in using term of precision and accuracy and pay no attention to measure precisely. Also they only point out sources of error but don't consider how the error affects the results of experiment. The results of study will give! 1 some implications for the curriculum and teaching material developers in order that pre-service teacher and student gain scientific concept.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.559-563
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• 2015

Monitor of All-sky X-ray Image (MAXI) is a Japanese X-ray all-sky surveyer mounted on the International Space Station (ISS). It has been scanning the whole sky since 2009 during every 92-minute ISS rotation. X-ray transients are quickly found by the real-time nova-search program. As a result, MAXI has issued 133 Astronomer's Telegrams and 44 Gamma-ray burst Coordinated Networks so far. MAXI has discovered six new black holes (BH) in 4.5 years. Long-term behaviors of the MAXI BHs can be classified into two types by their outbursts; a fast-rise exponential-decay type and a fast-rise flat-top one. The slit camera is suitable for accumulating data over a long time. MAXI issued a 37-month catalog containing 500 sources above a ~0.6 mCrab detection limit at 4-10 keV in the region ${\mid}{b}{\mid}$ > $10^{\circ}$. The SSC instrument utilizing an X-ray CCD has detected diffuse soft X-rays extending over a large solid angle, such as the Cygnus super bubble. MAXI/SSC has also detcted a Ne emission line from the rapid soft X-ray nova MAXI J0158-744. The overall shapes of outbursts in Be X-ray binaries (BeXRB) are precisely observed with MAXI/GSC. BeXRB have two kinds of outbursts, a normal outburst and a giant one. The peak dates of the subsequent giant outbursts of A0535+26 repeated with a different period than the orbital one. The Be stellar disk is considered to either have a precession motion or a distorted shape. The long-term behaviors of low-mass X-ray binaries (LMXB) containing weakly magnetized neutron stars are investigated. Transient LMXBs (Aql X-1 and 4U 1608-52) repeated outbursts every 200-1000 days, which is understood by the limit-cycle of hydrogen ionization states in the outer accretion disk. A third state (very dim state) in Aql X-1 and 4U 1608-52 was interpreted as the propeller effect in the unified picture of LMXB. Cir X-1 is a peculiar source in the sense that its long-term behavior is not like typical LMXBs. The luminosity sometimes decreases suddenly at periastron. It might be explained by the stripping of the outer accretion disk by a clumpy stellar wind. MAXI observed 64 large flares from 22 active stars (RS CVns, dMe stars, Argol types, young stellar objects) over 4 years. The total energies are $10^{34}-10^{36}$ erg $s^{-1}$. Since MAXI can measure the spectrum (temperature and emission measure), we can estimate the size of the plasma and the magnetic fields. The size sometimes exceeds the size of the star. The magnetic field is in the range of 10-100 gauss, which is a typical value for solar flares.

• Journal of the Korean Vacuum Society
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• v.19 no.4
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• pp.249-255
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• 2010

Methods of the characteristics evaluation of turbo-molecular pumps (TMP) are well-defined in the international measurement standards such as ISO, PNEUROP, DIN, JIS, and AVS. The Vacuum Center in the Korea Research Institute of Standards and Science (KRISS) has recently designed, constructed, and established the integrated characteristics evaluation system of TMPs based on the international documents by continuously pursuing and acquiring the reliable international credibility through measurement perfection. The measurement of TMP pumping speed is normally performed with the throughput and orifice methods dependent on the mass flow regions. However, in the UHV range of the molecular flow region, the high uncertainties of the gauges, mass flow rates, and conductance are too critical to precisely accumulate reliable data. In order to solve the uncertainty problems of pumping speeds in the UHV range, we introduced a SRG with 1% accuracy and a constant volume flow meter (CVFM) to measure the finite mass flow rates down to $10^{-1}$ Pa-L/s with 3% uncertainty for the throughput method. In this way we have performed the measurement of pumping speed down to $10^{-4}$ Pa with an uncertainty of less than 6% for a 1000 L/s TMP. In this article we suggest that the CVFM has an ability to measure the conductance of the orifice experimentally with flowing the known mass through the orifice chambers, so that we may overcome the discontinuity problem encountering during introducing two measurement methods in one pumping speed evaluation sequence.

• The Journal of Engineering Geology
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• v.12 no.4
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• pp.405-419
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• 2002

Fracture roughness of rock specimens is observed by a new confocal laser scanning microscope (CLSM; Olympus OLS1100). The wave length of laser is 488 nm, and the laser scanning is managed by a light polarization method using two galvano-meter scanner mirrors. The function of laser reflection auto-focusing enables us to measure line data fast and precisely. The system improves resolution in the light axis (namely z) direction because of the confocal optics. Using the CLSM, it is Possible to measure a specimen of the size up to $10{\;}{\times}{\;}10{\;}cm$ which is fixed on a specially designed stage. A sampling is managed in a spacing $2.5{\;}\mu\textrm{m}$ along x and y directions. The highest measurement resolution of z direction is $10{\;}\mu\textrm{m}$, which is more accurate than other methods. Core specimens of coarse and fine grained granite are provided. Fractures are artificially maneuvered by a Brazilian test method. Measurements are performed along three scan lines on each fracture surface. The measured data are represented as 2-D and 3-D digital images showing detailed features of roughness. Line profiles of the coarse granites represent more frequent change of undulation than those of the fine granite. Spectral analyses by the fast Fourier transform (FFT) are performed to characterize the roughness data quantitatively and to identify influential frequency of roughness. The FFT results suggest that a specimen loaded by large and low frequency energy tends to have high values of undulation change and large wave length of fracture roughness.