• Korean Journal of Mathematics
• /
• v.21 no.1
• /
• pp.75-80
• /
• 2013

Let T be a bounded linear operator on a complex Hilbert space $\mathfrak{H}$. An operator T is called class A operator if ${\mid}T^2{\mid}{\geq}{\mid}T{\mid}^2$ and is called class $A({\kappa})$ operator if $(T^*{\mid}T{\mid}^{2{\kappa}}T)^{\frac{1}{{\kappa}+1}}{\geq}{\mid}T{\mid}^2$ for a positive number ${\kappa}$. In this paper, we show that ${\sigma}$ is continuous when restricted to the set of class $A({\kappa})$ operators.

• Proceedings of the KSME Conference
• /
• 2002.08a
• /
• pp.819-822
• /
• 2002

It is necessary for the numerical simulation of 3-dimensional incompressible isotropic decaying turbulence to construct 3-dimensional initial velocity field which resembles the fully developed turbulence. Although the previous velocity field generation method proposed by Rogallo(1981) satisfies continuity equation and 3-dimensional energy spectrum, it has limitation, as indicated in his paper, that it does not produce the higher velocity moments(e. g. velocity derivative skewness) characteristic of real turbulence. In this study, a new velocity field generation method which is able to control velocity derivative skewness of initial velocity field is proposed. Brief descriptions of the new method and a few parameters which is used to control velocity derivative skewness are given. A large eddy simulation(LES) of isotropic decaying turbulence using dynamic subgrid-scale model is carried out to evaluate the performance of the initial velocity field generated by the new method. It was shown that the resolved turbulent kinetic energy decay curve and the resolved enstrophy decay curve from the initial field of new method were more realistic than those from the initial field of Rogallo's method. It was found that the dynamic model coefficient from the former was initially half the stationary value and experienced relatively short transition period, though that from the latter was initially zero and experienced relatively longer transition period.

• Journal of Communications and Networks
• /
• v.17 no.2
• /
• pp.172-183
• /
• 2015

To provide an efficient link maintenance approach, we propose a cross layer medium access control (LM-MAC) protocol for multichannel cognitive radio ad hoc networks. Link establishment and reliable transmission are two key problems for a perfect link maintenance mechanism. Since the cognitive user (CU) pairs have to reestablish their links each frame, in the proposed MAC protocol, three different access modes are designed to guarantee transmission efficiency in continuous frames. To enhance the transmission reliability, each CU will create a father spectrum list (FSL) after joining in the network. FSL is divided into three groups of sub-channels with different functions to compensate the packet loss caused by the primary users' appearance and the deep fading. Meanwhile, since the transmitter and the receiver will share the same FSL, periodical cooperative sensing is adopted to further optimize the former problem. Finally, compared with the existing opportunistic multichannel (OMC)-MAC protocol, the proposed LM-MAC protocol achieves better system performance in terms of saturation throughput, continuity and access delay.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
• /
• v.28 no.2
• /
• pp.96-105
• /
• 2017

Objectives: The purpose of this study is to investigate the professional knowledge and perceptions of the early screening of Autism Spectrum Disorder (ASD) in practitioners who have contact with patients with ASD. Methods: A survey was carried out among 674 practitioners in total, where practitioners are defined as those who work at primary medical centers, public institutions, educational institutions and treatment institutions. The survey was carried out both online and offline, and it mainly focused on 1) knowledge about ASD symptoms, 2) knowledge about the early screening of ASD, 3) measures taken after ASD detection, 4) thoughts on the development of early screening tools for ASD, and 5) the current status of ASD treatment. The data collected were analyzed through descriptive statistics, analysis of frequency and cross tabulation analysis using SPSS WIN 22.0. Results: The results of this study suggest that the practitioners were not aware of the exact symptoms of ASD and their professional knowledge and the environment for early screening were insufficient. Furthermore, very few and inappropriate measures were taken after the detection of ASD. In addition, there was a high demand for early ASD screening tools to be used on site and, regarding treatment, the significance of the implementation of evidence based treatments as well as the continuity of relevant research came to the fore. Conclusion: It seems that there is a lack of knowledge and perception of the early screening of ASD and that education and training among practitioners is urgently required. This issue is discussed in more detail in the paper.

• Journal of the Daesoon Academy of Sciences
• /
• v.26
• /
• pp.111-142
• /
• 2016

'In-Jon(人尊)' is one of a concept which constitute the mainstay of Daesoon thought. To be superficial, the concept is appeared to be limited at a area of anthropology, but In-Jon is a large concept which includes ontology and epistemology. Because the essence of human being is connected with God and the such possibility is related to the mission of human being's subject who exists in world. Advanced researches to analysis of in-jon tend to focus on rise of human status but this study do on universal subject not particular subject. This is to elaborate the point of issue. The point of view as rise of human status overlooks problem of relationship between human entities. who ingenerate hierarchy. In-jon is the universal subject of philosophical subject concepts which western philosophy have taken as main problem since Descartes. So we have to consider In-jon to be conceptual continuity concerning stream of history of ideas and communicate with ideas. A precedent study on 'injon' concept has weak conceptual analysis, which only emphasizes the greatness of mankind as compared with others. But that can't reveal In-jon based on the Daesoon thought. So I try to engraft the concept on development of subject ideas to get academic objectivity. In-jon is great in having universal subject to expand the authority of God to all creation. That is the last goal which subject can reaches through the development. Considering this regard the research direction of this study is very encouraging and significant. Western philosophy has important philosopher of the three, Descartes, Kant, Hegel. Those are a spectrum who show an aspect of subject ideas. The subject idea has become the middle of philosophical system since Descartes in modern. It is the right and necessary process to philosophy because human being has spirit or reason connected with God. So In-jon in Daesoon thought is academic concept comprising ontological and epistemological properties. So I try to analyse In-jon through that and have In-jon join the ranks of mainstream academics in this paper

• Korean Journal of Remote Sensing
• /
• v.39 no.6_2
• /
• pp.1541-1551
• /
• 2023

Radiometric calibration is a fundamental step in ocean color remote sensing since the step to derive solar radiance spectrum in visible to near-infrared wavelengths from the sensor-observed electromagnetic signals. Generally, satellite sensor suffers from degradation over the mission period, which results in biases/uncertainties in radiometric calibration and the final ocean products such as water-leaving radiance, chlorophyll-a concentration, and colored dissolved organic matter. Therefore, the importance of radiometric calibration for the continuity of ocean color satellites has been emphasized internationally. This study introduces an approach to improve the radiometric calibration algorithm for the visible bands of the Geostationary Ocean Color Imager-II (GOCI-II) satellite with a focus on stability. Solar Diffuser (SD) measurements were employed as an on-orbit radiometric calibration reference, to obtain the continuous monitoring of absolute gain values. Time series analysis of GOCI-II absolute gains revealed seasonal variations depending on the azimuth angle, as well as long-term trends by possible sensor degradation effects. To resolve the complexities in gain variability, an azimuth angle correction model was developed to eliminate seasonal periodicity, and a sensor degradation correction model was applied to estimate nonlinear trends in the absolute gain parameters. The results demonstrate the effects of the azimuth angle correction and sensor degradation correction model on the spectrum of Top of Atmosphere (TOA) radiance, confirming the capability for improving the long-term stability of GOCI-II data.

• ETRI Journal
• /
• v.42 no.5
• /
• pp.669-685
• /
• 2020

5G AgiLe and fLexible integration of SaTellite And cellulaR (5G-ALLSTAR) is a Korea-Europe (KR-EU) collaborative project for developing multi-connectivity (MC) technologies that integrate cellular and satellite networks to provide seamless, reliable, and ubiquitous broadband communication services and improve service continuity for 5G and beyond. The main scope of this project entails the prototype development of a millimeter-wave 5G New Radio (NR)-based cellular system, an investigation of the feasibility of an NR-based satellite system and its integration with cellular systems, and a study of spectrum sharing and interference management techniques for MC. This article reviews recent research activities and presents preliminary results and a plan for the proof of concept (PoC) of three representative use cases (UCs) and one joint KR-EU UC. The feasibility of each UC and superiority of the developed technologies will be validated with key performance indicators using corresponding PoC platforms. The final achievements of the project are expected to eventually contribute to the technical evolution of 5G, which will pave the road for next-generation communications.

• Journal of Korea Entertainment Industry Association
• /
• v.15 no.5
• /
• pp.85-98
• /
• 2021

The present thesis is a study about a character actor's characterization from the concept of 'star persona'. Conducted in 2020, this is a follow-up study about a personality actor's characterization. Lee Sung-min was selected due to his wide acting spectrum among domestic actors and his brilliant expression of differing characters as a character actor. The study discusses characterization methods for character actors on the basis of his role of high-ranking North Korean bureaucrat 'Ri Myung-un' in the film 'The Spy Gone North'. Stanislavski claimed that character building or characterization was the pinnacle of the acting art. However, such an expression of personality requires hard work and devotion from an actor. The actor Lee Sung-min practiced the North Korean dialect in order to act the role, and added the way the elite speak in North Korea to this dialect. He achieves a style of acting that raises tensions within the drama by spitting out lines in one breath and by making the audience fixate their gaze within character solo shots for which the character's emotions and lines serve as the core, with the purpose of maximizing dramatic tension and situational reality. Continuity and angle also serve extremely important roles in terms of expressing a character's personality development, affect, and emotions. The present thesis discussed the character development methods for a character actor's role of 'Ri Myung-un' in the film 'The Spy Gone North'.

• Journal of Navigation and Port Research
• /
• v.35 no.1
• /
• pp.45-49
• /
• 2011

The recent trend for numerical experiment requires more higher resolution and accuracy. Generally, in the wave field calculation, it starts with a large region formulation first and follows by a separated detailed region formulation by more denser grids for the main interest area considering the geographical and bathymetrical variation. The wave fields resulted from the large region calculation is being introduced into the detail region calculation as the incident waves. In this process there exists a problem of continuity. In order to get over such problem, method of variable gridding system or spectrum sampling, etc., is being used. However, it seems not enough to examine and analyze the related numerical errors. Therefore, it is investigated in this study the field applicability of the most pervasive use of wave model, the nested SWAN model. For this purpose, we made model experiment for two coastal harbours with different tidal environment, and compared and analyzed the result. From the analysis, it was found that both the extracted values, near the boundaries of the large and detail region and the nested formulation of SWAN model, show almost the same and no different between those with different tidal environment conditions. However it is necessary for reducing the numerical errors to set the boundaries for the detailed region outside of the rapid bathymetric change and deeper region.