• Current Optics and Photonics
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• v.6 no.1
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• pp.10-14
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• 2022

Low-threshold optical bistability is essential for practical nonlinear optical applications. Many bistable optical devices based on high-quality-factor resonators have been proposed to reduce the threshold intensity. However, demonstrating high-quality-factor resonance requires complex fabrication techniques. In this work, we numerically demonstrate optical bistability with bound states in the continuum in a simple one-dimensional Si photonic crystal. The designed structure supports bound states in the continuum, producing an ultrahigh quality factor without tough fabrication conditions. The threshold intensity of the designed device is 150 MW/cm² at the optical communication wavelength. This scheme may lead to a new class of nonlinear photonics.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.1
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• pp.13-20
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• 2015

Existing LDMOS power amplifier that used class-AB and doherty system shows 55% of efficiency in 60MHz narrow band. Because RRH has been applied to power amplifier at base station. It is required that over 100MHz expanded band and more than 60% high efficiency power amplifier. In this paper we designed class-J power amplifier using LDMOS FET which has over 60% high efficiency characteristic in 200MHz. The output matching circuit of designed class-J power amplifier has been optimized to contain pure reactance at second harmonic load and has low quality factor Q. As a measurement result of the amplifier, when we input continuous wave signal, we checked 62~70% of power added efficiency(PAE) in 2.06~2.2GHz including WCDMA frequency as a 10W class-J power amplifier.

• Journal of Korean Clinical Health Science
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• v.1 no.3
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• pp.49-61
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• 2013

Purpose. The purpose of this study is to analyze difference in quality of life related to health according to our country's social stratification. Methods. This study had analytical subjects as 7,992 adults(4,557 men, 3,435 women), who are included in a variable by social stratification among 15,691 people in the age group of 20~69 years old as examinees, based on the 4th Korea National Health and Nutrition Examination Survey. Results. This study obtained the following results. First, seeing the score of health-related life quality by social stratification, namely, the distribution of EQ-5D index, the new middle class(class II) was the highest(men with 0.966 point, women with 0.955 point). The agricultural self-employed class(class V) was indicated to be the lowest(men with 0.918 point, women with 0.866 point). In general, the more belonging to low social stratification led to having shown the lower aspect in EQ-5D index value. Second, as for the results of the hierarchical regression analysis, the factors of contributing to difference by social stratification in health-related quality of life were chronic disease, job stress, education, and income level in both men and women. The health behavior was grasped to be a factor of contributing only to women. Conclusions. To reduce difference in health-related quality of life according to social stratification in the future, the continuous investment is needed for supporting socially high-quality education and economic stability. The sphere of health will need to be given priority to the prevention of chronic disease and the development in effective management policy for the lower classes.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.6
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• pp.901-910
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• 2002

This study is to classify somatotypes of the upper class boys in elementary school. The study is conducted through anthoropometric measurements and photometric measurements. The subjects are 320 boys in the age group of 10 to 11 years old. The following conclusions are drawn from this study. 1. The height items are increased along with age increase. The increases in the factors, which specify vertical sizes such as height and length, are a little larger than those of breadth, depth, and girth, which specify ; horizontal sizes. 2. The factor analysis on anthropometric measurements and photometric measurements reveals five somatic composition factors and those factors comprised 79.60% of total variance. 3. The torso shapes of the upper class boys in elementary school are classified into three categories. The first type is taller and heavier than the average elementary school upper class boys and has the highest rising shoulders. The shape of the back is about average and the chest is developed above average. The curvature of the lower back is gentle and lower abdomen protrudes the most of the three types. The second type is tall and slightly heavier than average and shoulders are raised a little. The shoulder blades protrude about average and the curvature of lower back is the most developed of all. The cheat is developed about average and the abdomen is a little protruding. The third type is the most common with the smallest height of the three and skinny with dropped shoulders. The chest is somewhat flat and the shoulder blades protrude about average.

• Journal of Korean Neurosurgical Society
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• v.41 no.5
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• pp.283-290
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• 2007

Objective : This study was designed to analyze seizure outcome and to investigate the prognostic factors for predicting seizure outcome according to the preoperative evaluations, surgical procedures, topectomy sites and histopathological findings in patients with extratemporal lobe epilepsy [ETLE]. Methods : This study comprised 63 patients with ETLE who underwent surgery. Preoperative evaluations included semiologic analysis, chronic video-EEG monitoring, and neuroimaging studies. Surgical procedures consisted of topectomy in 51 patients, corpus callosotomy in 9, functional hemispherectomy in 2, and vagus nerve stimulation [VNS] in 1. Histopathological findings were reviewed. Postoperative seizure outcomes were assessed by Engel's classification at the average follow up period of 66.8 months. Chi-square test was used for statistics. Results : Total postoperative seizure outcomes were class I in 51 [80%] patients, class II in 6 [10%], class III in 6 [10%]. Patients with structural abnormalities on neuroimaging study showed class I in 49 [88%] patients [p<0.05]. Patients with focal and regional ictal EEG onset revealed class I in 47 [90%] patients [p<0.05]. Semiologic findings, surgical procedures, topectomy sites and histopathological findings did not show statistical correlation with seizure outcome [p<0.05]. Conclusion : A good seizure outcome was obtained in patients with ETLE. The factors for favorable seizure outcome are related to the presence of structural abnormalities on neuroimaging study, and focal and regional ictal EEG onset.

• The korean journal of orthodontics
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• v.47 no.4
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• pp.248-255
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• 2017

Objective: The purpose of this study was to investigate whether the craniofacial patterns of Korean children with snoring and adenotonsillar hypertrophy (ATH) could be categorized into characteristic clusters according to age. Methods: We enrolled 236 children with snoring and ATH (age range, 5-12 years) in this study. They were subdivided into four age groups: 5-6, 7-8, 9-10, and 11-12 years. Based on cephalometric analysis, the sagittal and vertical skeletal patterns of each individual were divided into Class I, II, and III, as well as the normodivergent, hypodivergent, and hyperdivergent patterns, respectively. Cluster analysis was performed using cephalometric principal components in addition to the age factor. Results: Three heterogeneous clusters of craniofacial patterns were obtained in relation to age: cluster 1 (41.9%) included patients aged 5-8 years with a skeletal Class I or mild Class II and hyperdivergent pattern; cluster 2 (45.3%) included patients aged 9-12 years with a Class II and hyperdivergent pattern; and cluster 3 (12.8%) included patients aged 7-8 years with a Class III and hyperdivergent pattern. Conclusions: This study found that the craniofacial patterns of Korean children with snoring and ATH could be categorized into three characteristic clusters according to age groups. Although no significantly dominant sagittal skeletal discrepancy was observed, hyperdivergent vertical discrepancy was consistently evident in all clusters.

• The Journal of the Korea Contents Association
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• v.16 no.1
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• pp.167-178
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• 2016

This research is to understand the causal relationship between class participation motivation, acting expressiveness and psychological happiness through the class of the college students majoring in acting. For this purpose, the simple random sampling method was used and the college students majoring play and acting in the college located in Seoul and Gyeonggi-do as a sample group and total 499 questionnaires were used. For the questions, 73 questions of which the reliability and validity is examined were used. As for a data processing method, it used the statistical package of IBM STATISTICS SPSS 22 and AMOS 22 and analyzed the results by applying the descriptive statistics analysis, confirmatory factor analysis, reliability analysis and structural equation model. The conclusion of this research is as follows. Intrinsic motivation and extrinsic motivation among the class participation motivation of the college students majoring in acting have a significant effect on all sub factors of acting expressiveness and psychological happiness statically, and a motivation has no effect on it. Both personality and expressive impulse of acting expressiveness have an effect on a psychological happiness, and mobility has no effect on it.

• 대한공업교육학회지
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• v.37 no.2
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• pp.127-146
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• 2012

The purpose of this study is to exploring the procedure of developing hands-on activity and provide the generalized development procedure adjusted for the technology subject. The research method for this study is mainly based on document and experience. exploration of hands-on activity and development procedure of hands-on activity given by preceded researchers and the common factor was derived from them. For the result of the study. first. the concept of experience and hands-on activity was examined and the procedure of developing hands-on activity in technology education was reviewed. Second. suggested 3 steps for the procedure of developing hands-on activity in technology education ; preparation. development. improvement and the detailed steps. Third. presented contents included for hands-on activity task materials. For the teachers. those are ; hands-on activity subject. readings before the class. object for the course class. main activity in class courses. material. tools and facility. design brief. reference data. score sheet. detailed class process. For the students. those are; subject for class. matters to be attended to. portfolio and etc.

• Journal of Digital Convergence
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• v.19 no.5
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• pp.269-277
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• 2021

The purpose of the study is to explore the effect of university's managing and system support in online classes on learning participation mediated by learning presence and to examine the structural relationship between the factors. In order to achieve the purpose of the study, 135 students who take online "College English 2" classes were analyzed for the fitness of the research model and the path and structural analysis through a confirmative factor of the structural equation model. As a result of the study, first, the university's managing support for online class showed a positive effect to learning presence. Second, the university's managing support for online classes completely mediated learning presence and had a positive effect on learning participation. This study can clarify the structural relationship between environmental factors which are online class support and learners' characteristics in university online class, learning presence, and learning participation and can broaden the understanding of learning participation in online classes. It gives the implications that should be considered in teaching and learning design.

• Journal of fish pathology
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• v.27 no.1
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• pp.1-9
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• 2014

The olive flounder, Paralichthys olivaceus is susceptible to viral hemorrhagic septicaemia virus (VHSV) at $15^{\circ}C$ but no mortality at $20^{\circ}C$ even though the virus can grow well in vitro at $20^{\circ}C$. Thus, we designed an experiment to know immune response of olive flounder against VHSV when the host reared at $15^{\circ}C$ or $20^{\circ}C$. cDNA microarray analysis was performed to compare the gene expression patterns of the kidney cells between the host reared at $15^{\circ}C$ or $20^{\circ}C$. The expression of MHC class I, IL-8, myeloperoxidae and endonuclease G-like having function for the antigen presentation and chemokine-factor were up-regulted both the $15^{\circ}C$ and $20^{\circ}C$ during VHSV infection. MHC class II gene existing on antigen-presenting cells and B cell lymphocytes, immunoglobulin (Ig) genes and phagocytosis related genes were down-regulated at $15^{\circ}C$ but highly expressed at $20^{\circ}C$. It can be thought that innate immune related antigen presentation by MHC class I and phagocytosis reaction against VHSV are efficiently occur both the temperature but macrophage or B cell related antigen presentation via MHC class II fails to induce downstream immune reactions (adaptive immunity) to make antibody, and it can be one of the reason that causes high mortality only at $15^{\circ}C$.