• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.2
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• pp.36-47
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• 2006

The process of dual spin turn maneuver is introduced for attitude acquisition or recovery from flat spin state of a satellite. The physical principle of momentum transfer during dual spin turn is explained clearly. The case studies of special dual spin turn, in addition to the conventional dual spin turn, that are known as an acceptable cases, are performed to investigate the principle of dual spin turn and to provide a physical insight as well as the solution of dual spin turn. This study is done based on case-study simulation, which includes two-state control scheme composed of open-loop maneuver and energy dissipation device. Furthermore, we investigate the stability for the verification of all control cases after implementing two-stage control. We also provide the simulation scenario of flat spin recovery using dual spin turn method as an example.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.6
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• pp.2833-2839
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• 2016

Background: Tobacco use among youth is a major public health problem. Youth outside of formal school settings are often understudied but may be at increased risk. Materials and Methods: A descriptive cross-sectional study was carried out among 326 young people aged 15-24 years in four randomly selected motor parks in Lagos state. Interviewer-administered questionnaires were used to collect data. Results: The mean age of the respondents was $21.0{\pm}2.3yrs$. Many 252 (77.3%) dropped out before the end of the third year of secondary schooling. The majority were aware that active (78.2%), and passive smoking (77.3%) are harmful to health. Nearly two-thirds of the respondents disagreed with an outright ban of cigarettes (63.2%) and restriction of cigarette sales to persons below 18 years (67.9%) while 254 (66.8%) supported a ban on tobacco smoking in enclosed public places. One hundred and fifty (46.0%) respondents had experimented with smoking of which 106 (32.5%) had progressed to become current smokers. Half of the current smokers, 54 (50.9%), felt the need for a cigarette first thing in the morning. A multivariate analysis for smoking initiation, showed that for every increasing year of age, respondents were 1.08 times more likely to have initiated cigarette smoking; males and respondents who lived alone or with peers were 2.34 times and 1.77 times more likely to have initiated smoking respectively; those who consume alcohol and marijuana were 7.27 and 1.89 times respectively more likely to have initiated smoking while those who consumed alcohol were 6.17 times more likely to be current smokers.

• Wind and Structures
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• v.19 no.4
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• pp.421-441
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• 2014

With the assistance of typhoon field data at aerial elevation level observed by meteorological satellites and wind velocity and direction records nearby the ground gathered in Guangzhou Weather Station between 1985 and 2001, some key wind field parameters under typhoon climate in Guangzhou region were calibrated based on Monte-Carlo stochastic algorithm and Meng's typhoon numerical model. By using Peak Over Threshold method (POT) and Generalized Pareto Distribution (GPD), Wind field characteristics during typhoons for various return periods in several typical engineering fields were predicted, showing that some distribution rules in relation to gradient height of atmosphere boundary layer, power-law component of wind profile, gust factor and extreme wind velocity at 1-3s time interval are obviously different from corresponding items in Chinese wind load Codes. In order to evaluate the influence of typhoon field parameters on long-span flexible bridges, 1:100 reduced-scale wind field of type B terrain was reillustrated under typhoon and normal conditions utilizing passive turbulence generators in TJ-3 wind tunnel, and wind-induced performance tests of aero-elastic model of long-span Guangzhou Xinguang arch bridge were carried out as well. Furthermore, aerodynamic admittance function about lattice cross section in mid-span arch lib under the condition of higher turbulence intensity of typhoon field was identified via using high-frequency force-measured balance. Based on identified aerodynamic admittance expressions, Wind-induced stochastic vibration of Xinguang arch bridge under typhoon and normal climates was calculated and compared, considering structural geometrical non-linearity, stochastic wind attack angle effects, etc. Thus, the aerodynamic response characteristics under typhoon and normal conditions can be illustrated and checked, which are of satisfactory response results for different oncoming wind velocities with resemblance to those wind tunnel testing data under the two types of climate modes.

• Journal of IKEEE
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• v.25 no.2
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• pp.362-370
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• 2021

In this paper, we propose the Autonomous Stair-climbing system based on data from ToF sensors and IMU in developing stair-climbing robots to passive wheelchair users. Autonomous stair-climbing system are controlled by separating the timing of landing gear operation by location and utilizing state machines. To prove the theory, we construct and experiment with standard model stairs. Through an experiment to get the Attack angle, the average error of operating landing gear was 2.19% and the average error of the Attack angle was 2.78%, and the step division and status transition of the autonomous stair-climbing system were verified. As a result, the performance of the proposed techniques will reduce constraints of transportation handicapped.

• Journal of the Korean Society of Safety
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• v.36 no.3
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• pp.74-80
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• 2021

Korea Atomic Energy Research Institute (KAERI) has been operating an integral effects test facility, the Advanced Thermal-Hydraulic Test Loop for Accident Simulation (ATLAS), according to APR1400 for transient experimental and design basis accident simulation. Moreover, based on the experimental data, the domestic standard problem (DSP) program has been conducted in Korea to validate system codes. Recently, through DSP-05, the performance of the passive auxiliary feedwater system (PAFS) in the event of multiple steam generator tube rupture (MSGTR) has been analyzed. However, some errors exist in the reference input model distributed for DSP-05. Furthermore, the calculation results of the heat loss correlation for the secondary system presented in the technical report of the reference indicate that a large difference is present in heat loss from the target value. Thus, in this study, the reference model is corrected using the geometric information from the design report and drawings of ATLAS. Additionally, a new heat loss correlation is suggested by fitting the results of the heat loss tests. Herein, MSGTR-PAFS accident analysis is performed using MARS-KS 1.5 with the improved model. The steady-state calculation results do not significantly differ from the experimental values, and the overall physical behavior of the transient state is properly predicted. Particularly, the predicted operating time of PAFS is similar to the experimental results obtained by the modified model. Furthermore, the operating time of PAFS varies according to the heat loss of the secondary system, and the sensitivity analysis results for the heat loss of the secondary system are presented.

• International Journal of Computer Science & Network Security
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• v.22 no.9
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• pp.43-50
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• 2022

For high-quality education of the modern generation of students, forms of organizing the educational process and the latest methods of obtaining knowledge that differ from traditional ones are necessary. The importance of multimedia teaching tools is shown, which are promising and highly effective tools that allow the teacher not only to present an array of information in a larger volume than traditional sources of information, but also to include text, graphs, diagrams, sound, animation, video, etc. in a visually integrated form. Approaches to the classification of multimedia learning tools are revealed. Special features, advantages of multimedia, expediency of use and their disadvantages are highlighted. A comprehensive analysis of the capabilities of multimedia teaching tools gave grounds for identifying the didactic functions that they perform. Several areas of multimedia application are described. Multimedia technologies make it possible to implement several basic methods of pedagogical activity, which are traditionally divided into active and passive principles of student interaction with the computer, which are revealed in the article. Important conditions for the implementation of multimedia technologies in the educational process are indicated. The feasibility of using multimedia in education is illustrated by examples. Of particular importance in education are game forms of learning, in the implementation of which educational elements based on media material play an important role. The influence of the game on the development of attention by means of works of media culture, which are very diverse in form and character, is shown. The importance of the role of multimedia in student education is indicated. In the educational process of multimedia students, a number of educational functions are implemented, which are presented in the article. Recommendations for using multimedia are given.

• International Journal of Advanced Culture Technology
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• v.11 no.3
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• pp.99-105
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• 2023

This thesis discusses a performer's unpredictability and immediacy as a prerequisite quality and/or ability to facilitate his/her professional identity as a doer on stage. To examine the key principles and approaches, this research focuses on addressing a specific aspect of the performer's transformative experience from those, directors, and practitioners' concepts that inform and enhance the performer's passive readiness on stage. To be precise, this research attempt to interrogate and articulate the place and role of a performer's internal readiness and/or that of inner looking. The performer's inner intensity as seed of action signifies that his/her body is being in a state of listening to every tiny moment with his/her heightened awareness which in turn lead the performer's body to meet the demands of theatre, the whole-body engagement. Here, this thesis argues that the key principles of acting/training underlies the importance of a performer's ethical attitude and at the same time his/her responsibility for what the performer's choices and experiences within the performative involvement, that is, a process of preparation, are not technical matter but rather, the concepts, and/or approaches from those theatre artists' practical assumptions highlight a process of thorough encountering and/or listening to his/her body. Inhabiting and/or obtaining the principles through the performer's body means being free from his/her unnecessary trait(s) which in turn initiate and then move the whole body according to what is happening in the series of moment(s) on stage. What is more, such an appropriate psychophysical order reminds us of the significance of the nature of human/performer's body, namely, to being in a state of one's 'own' body as oneness. From this perspective, this thesis further argues that the performer's body necessarily need to be affected and/or triggered in a sense of responding to the given circumstance where the performer is working on in the here and now.

• The Journal of Korean Medical History
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• v.36 no.1
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• pp.31-50
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• 2023

Through this paper, all the provisions of the enforcement statutes stipulated in the Joseon's law code were investigated and major medical issues and interests in the Joseon Dynasty were analyzed. The characteristics of each period reviewed in the text are as follows. The early Joseon Dynasty is divided into three periods. First of all, Joseon filled the gap in the law with the active acceptance of the Ming Dynasty's law code, Daemyeongrul, which conformed to Confucian virtue. Next, the completion of Gyeonggukdaejeon was an opportunity to prepare the basis for Joseon's medical laws. Lastly, from the late 15th century to the 16th century, the existing medicine promotion measures and emphasis on hyangyak(domestic herb) continued. it can be said that Joseon's politicians needed a medical policy based on Confucian virtues and maintained state-led promotion policies, but on the other hand, there was no other alternative to try newly by reflecting the limitations and failures of the policy. The late Joseon Dynasty is also divided into three periods. First of all, the period from the late 16th century to the early 18th century was marked by the growth of families in technical positions. The era of King Yeongjo can be said to be the period of reorganization of medical related laws. Finally, the period after the late 18th century is a period of passive regulation and supplementation. Lastly, the revision of the actual medical law was not made or reflected in era of King Jeongjo. In the case of the early Joseon Dynasty, the policy shifted from state-led to families in technical positions. However, in the 19th century, the weakening of the royal authority led to the weakening of the overall administrative system of the country, and the pharmaceutical policy had to be limited.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.11B
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• pp.980-990
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• 2004

In this paper, we propose the dynamic bandwidth allocation algorithm for the IEEE802.3ah Ethernet Passive Optical Network(EPON) system to provide the fairness among terminals, and evaluate the delay-throughput performance by simulation. For the conventional EPON systems, an Optical Line Termination (OLT) schedules the upstream bandwidth for each Optical Network Unit (ONU), based on its buffer state. This scheme can provide a fair bandwidth allocation for each ONU. However, it has a critical problem that it does not guarantee the fair bandwidth among terminals which are connected to ONUs. For an example, we assume that the traffic from a greedy terminal increases at a time. Then, the buffer state of its ONU is instantly reported to the OLT, and finally the OW can get more bandwidth. As a result, the less bandwidth is allocated to the other ONUs, and thus the transfer delay of terminals connected to the ONUs gets inevitably increased. Noting that this unfairness problem exists in the conventional EPON systems, we propose a fair bandwidth allocation scheme by OLT with considering the buffer state of ONU as welt as the number of terminals connected it. For the performance evaluation, we develop the EPON simulation model with SIMULA simulation language. From the result of the throughput-delay performance and the dynamics of buffer state along time for each terminal and ONU, respectively, one can see that the proposed scheme can provide the fairness among not ONUs but terminals. Finally, it is worthwhile to note that the proposed scheme for the public EPON systems might be an attractive solution for providing the fairness among subscriber terminals.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.5
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• pp.15-21
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• 2009

An Ethernet passive optical network (EPON) is an economical and efficient access network that received significant research attention in recent year. A MAC protocol of the PON, the next generation access network, is based primarily on TDMA (Time Division Multiple Access). In this paper, we addressed the problems of a dynamic bandwidth allocation (DBA) in Fairness and QoS Performance. We augmented the advanced bandwidth allocation algorithms to support efficient resource utilization by reducing the unused remaining bandwidth made by idle state ONUs. Our new proposed advanced bandwidth allocation algorithm can allocate effectively and fairly the bandwidths between end-users.