• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.6
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• pp.504-509
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• 2011

The conducting current of non-uniform plasma immersed electrode consists of ion current and secondary electron emission current caused by the impinging ion current. The ion current is determined by the ion dose passing through the sheath in front of electrode and the ion distribution in front of the electrode plays an important role in the secondary electron emission. The investigation of the distributed plasma and secondary electron effect on electrode ion current was carried out as the stainless steel electrode plugged with quartz tube was immersed in the inductively coupled Ar plasma using the antenna powered by 1 kw and the density profile was measured. After that, the negative voltage was applied by 1 kV~6 kV to measure the conduction current for the analysis of ion current.

• Journal of the Semiconductor & Display Technology
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• v.16 no.4
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• pp.91-96
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• 2017

In this computational study of optical fiber manufacturing, WOW (wet-on-wet) double coating process on freshly drawn glass fiber has been numerical modelled and simulated using a simplified geometry of typical optical fiber coating apparatus. The numerical domain includes primary and secondary coating dies along with secondary coating cup and the interface between primary and secondary coating liquids are investigated using level set method. Coating liquid viscosity is an important parameter and its dependence on temperature is also considered. Since there would be possibility for pressure and temperature of primary coating liquid to be increased substantially at high fiber drawing speed, the effects of increased pressure and temperature of primary coating liquid are examined on flow patterns of coating liquids in secondary coating cup. In case that both pressure and temperature of primary coating liquid are high enough, liquid interface becomes noticeably unstable and this flow instability could adversely affect the uniform coatings and final quality of produced optical fiber.

• ETRI Journal
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• v.45 no.1
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• pp.28-44
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• 2023

We propose short packet communication in an underlay cognitive radio network assisted by an intelligent reflecting surface (IRS) composed of multiple reconfigurable reflectors. This scheme, called the IRS protocol, operates in only one time slot (TS) using the IRS. The IRS adjusts its phases to give zero received cumulative phase at the secondary destination, thereby enhancing the end-to-end signal-to-noise ratio. The transmitting power of the secondary source is optimized to simultaneously satisfy the multi-interference constraints, hardware limitations, and performance improvement. Simulation and analysis results of the average block error rates (BLERs) show that the performance can be enhanced by installing more reconfigurable reflectors, increasing the blocklength, lowering the number of required primary receivers, or sending fewer information bits. Moreover, the proposed IRS protocol always outperforms underlay relaying protocols using two TSs for data transmission, and achieves the best average BLER at identical transmission distances between the secondary source and secondary destination. The theoretical analyses are confirmed by Monte Carlo simulations.

• Journal of Communications and Networks
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• v.16 no.2
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• pp.227-237
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• 2014

Throughput scaling laws for two coexisting ad hoc networks with m primary users (PUs) and n secondary users (SUs) randomly distributed in an unit area have been widely studied. Early work showed that the secondary network performs as well as stand-alone networks, namely, the per-node throughput of the secondary networks is ${\Theta}(1/\sqrt{n{\log}n})$. In this paper, we show that by exploiting directional spectrum opportunities in secondary network, the throughput of secondary network can be improved. If the beamwidth of secondary transmitter (TX)'s main lobe is ${\delta}=o(1/{\log}n)$, SUs can achieve a per-node throughput of ${\Theta}(1/\sqrt{n{\log}n})$ for directional transmission and omni reception (DTOR), which is ${\Theta}({\log}n)$ times higher than the throughput with-out directional transmission. On the contrary, if ${\delta}={\omega}(1/{\log}n)$, the throughput gain of SUs is $2{\pi}/{\delta}$ for DTOR compared with the throughput without directional antennas. Similarly, we have derived the throughput for other cases of directional transmission. The connectivity is another critical metric to evaluate the performance of random ad hoc networks. The relation between the number of SUs n and the number of PUs m is assumed to be $n=m^{\beta}$. We show that with the HDP-VDP routing scheme, which is widely employed in the analysis of throughput scaling laws of ad hoc networks, the connectivity of a single SU can be guaranteed when ${\beta}$ > 1, and the connectivity of a single secondary path can be guaranteed when ${\beta}$ > 2. While circumventing routing can improve the connectivity of cognitive radio ad hoc network, we verify that the connectivity of a single SU as well as a single secondary path can be guaranteed when ${\beta}$ > 1. Thus, to achieve the connectivity of secondary networks, the density of SUs should be (asymptotically) bigger than that of PUs.

• Journal of Microbiology and Biotechnology
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• v.21 no.1
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• pp.5-13
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• 2011

In this study, seven Trichoderma species (33 strains) were classified using secondary metabolite profile-based chemotaxonomy. Secondary metabolites were analyzed by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS-MS) and multivariate statistical methods. T. longibrachiatum and T. virens were independently clustered based on both internal transcribed spacer (ITS) sequence and secondary metabolite analyses. T. harzianum formed three subclusters in the ITS-based phylogenetic tree and two subclusters in the metabolitebased dendrogram. In contrast, T. koningii and T. atroviride strains were mixed in one cluster in the phylogenetic tree, whereas T. koningii was grouped in a different subcluster from T. atroviride and T. hamatum in the chemotaxonomic tree. Partial least-squares discriminant analysis (PLS-DA) was applied to determine which metabolites were responsible for the clustering patterns observed for the different Trichoderma strains. The metabolites were hetelidic acid, sorbicillinol, trichodermanone C, giocladic acid, bisorbicillinol, and three unidentified compounds in the comparison of T. virens and T. longibrachiatum; harzianic acid, demethylharzianic acid, homoharzianic acid, and three unidentified compounds in T. harzianum I and II; and koninginin B, E, and D, and six unidentified compounds in T. koningii and T. atroviride. The results of this study demonstrate that secondary metabolite profiling-based chemotaxonomy has distinct advantages relative to ITS-based classification, since it identified new Trichoderma clusters that were not found using the latter approach.

• Journal of the Korea Convergence Society
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• v.11 no.4
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• pp.311-321
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• 2020

The purpose of this study was to analyze the recognition of secondary pre-physical education teachers' recognition for the learning athletics using Q methodology. P-sample was composed of 28 pre-secondary P·E teachers. The selected Q samples were arranged in the normal distribution form. The collected data were analyzed by factor analysis through varimax rotation using QUANL PC program. This study found four types of recognition on learning athletics. Type I is defined 'the type of recognition for education value.' Type II is defined 'the type of emphasizing assistant activities.' Type III is defined 'the type of an appeal difficulty to learn athletics skill.' Type IV is defined 'the type of emphasizing the basic movement value.' Based of the results of this study, the implications and direction to future research on athletics activities are suggested.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.5
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• pp.631-640
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• 2013

This paper provides a comparison of the J-integral estimation method under combined primary and secondary stress in the R6, RCC-MR A16 code. The comparisons of each code are based on finite element analysis using ABAQUS with regard to the crack shape, crack depth, and magnitude of secondary load. The estimate of the R6 code is conservative near $L_r=1$, and that of the RCC-MR A16 code is conservative near $L_r=0$. As a result, this paper proposes a modified method of J-integral estimation in the R6, RCC_MR A16 code. The J-integral using the modified method corresponds to the finite element analysis result.

• Journal of the Korean Data and Information Science Society
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• v.28 no.6
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• pp.1539-1545
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• 2017

In this paper, we analyze and discuss the trend of the probability and statistics problems that have been made in the public secondary school teacher employment exam for mathematics teachers. In order to properly teach the national mathematics curriculum in 2015 in terms of content and function, we investigate the probability and statistics contents that a mathematics teachers should know. We also analyze the contents and trends of the items that have been submitted for 15 years in public secondary school teacher employment exam, and discuss the contents, scope, level and direction of the future contents. In conclusion, considering the significance of the Big Data in the 4th industrial revolution, the problems of statistical thinking of data and probability, exploratory data analysis, sample survey, and statistical inference are needed more.

• Journal of Digital Convergence
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• v.19 no.4
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• pp.339-347
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• 2021

The purpose was to analyze the trend of sport pedagogy in secondary teacher certification examination based on the secondary teacher qualification criterion in Korea Institute for Curriculum and Evaluation since abolition of multiple-choice questions from 2014 to 2020. The result showed the questions for sport pedagogy were 48 question since 2014, and found 83 sub-questions. The implications are as follows. First, the frequency of sub-questions in sport pedagogy has increased, causing an integrated question. Second, the serious unbalanced issue of questions for examination was presented. Third, dependence on specific domains was excessively high. Fourth, the confusion caused by the overlapped domains with the content knowledge of physical education subject was intensified. Therefore, evaluation factors based on 2016 KICE classification table should be clear and field application questions should be developed.

• Journal of Veterinary Clinics
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• v.39 no.5
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• pp.235-239
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• 2022

A 10-year-old neutered male Siberian Husky presented with paraparesis and severe lethargy. On physical examination, the patient was unable to weight-bear and walk and exhibited significant muscle mass loss in both hindlimbs and generalized truncal alopecia with a dull coat of hair. On neurological examination, cranial lumbar vertebral pain, hind limb cross-extensor reflex, delayed hindlimb postural reaction, upper motor neuron bladder dysfunction, and total absence of cutaneous trunci reflex were identified. Computed tomography revealed diffuse idiopathic skeletal hyperostosis and spondylosis deformans of the cervical and thoracolumbar vertebrae. In addition, a generalized decrease in bone mineral density of the vertebrae was identified. Magnetic resonance imaging showed hyperplasia of the epidural fat compressing the spinal cord in the thoracolumbar region and concurrent mild multiple intervertebral disc herniations. No specific findings were observed in cerebrospinal fluid analysis. Blood analysis of thyroid function revealed decreased total T4 and free T4 levels, and increased TSH levels. The patient was tentatively diagnosed with spinal epidural lipomatosis (SEL) secondary to hypothyroidism. The patient was treated with levothyroxine, firocoxib, and gabapentin. Clinical signs gradually improved, and the patient showed normal ambulation 40 days after treatment initiation. SEL is extremely rare in dogs. To the best of our knowledge, this is the first case report of SEL secondary to hypothyroidism that was treated conservatively. Secondary SEL can be sufficiently managed by treating the underlying cause, if possible.